WO2004057425A1

WO2004057425A1 - Method for the treatment of a resist system and corresponding device

Info

Publication number: WO2004057425A1
Application number: PCT/DE2003/004236
Authority: WO
Inventors: Wolf-Dieter Domke; Karl Kragler; Klaus Lowack; Siegfried Schwarzl
Original assignee: Infineon Technologies Ag
Priority date: 2002-12-20
Filing date: 2003-12-16
Publication date: 2004-07-08
Also published as: AU2003296546A1; DE10261845A1

Abstract

The invention relates to a method and a device for the treatment of a resist system for the production of a semiconductor element, whereby the resist system (1) comprises polar and/or charged components, characterised in that, after the exposure of the resist system (1) on a substrate (2), the resist system (1) is subjected to an electrical field (10) to influence the movement of the polar and/or charged components of the resist system (1). The lateral diffusion of charged and/or polar components of the resist system can thus be reduced or prevented.

Description

description

Process for treating a resist system and device therefor

The invention relates to a method according to the preamble of claim 1 and an apparatus for carrying out the method / according to claim 29.

So-called chemical amplification resists (CAR) are widely used in microelectronics for various optical lithography processes (wavelengths: 248nm, 193nm, 157 nm). This is e.g. in the article by Hiroshi Ito "Deep-UV resists: Evolution and Status", Solid-State Technology, July'1996, p. 164 ff. Chemically amplified resists, especially with onium compounds as photo acid generators, are also described in Reichmanis et al. "Chemically amplified resists: Chemistry and Processes", Advanced Materials for Optics and Electronics, Vol. 4, 83-93, 1994.

The resist systems can work on the principle of acid catalytic cleavage. In the case of a positive resist, a polar carboxylic acid group is formed from a non-polar chemical group, for example a carboxylic acid tert-butyl ester group, in the presence of a photolytically generated acid (Photo Acid Generator: PAG; photo acid generator).

Added bases can affect the diffusion length of the photo acid produced, which affects both line roughness and sensitivity of the resist system. In a subsequent development step, the exposed resist film is treated with aqueous alkaline developer solutions, the carbonic acid-rich, polar regions being developed away and the unexposed resist regions remaining. Resist materials that can resolve structures down to 65 nm in size will likely be required to manufacture DRAMs by 2007. For the year 2016, even a resolution of 22 nm DRAM 1/2 pitch will be necessary. With the currently used

Exposure wavelengths of 248 or 193 nm or even at the future wavelength of 157 nm, these structures can no longer be generated. For future generations of lithography, optical lithography will therefore advance into the extremely short-wave range of approximately 13.4 nm (EUV) or even into the X-ray range.

As the structure size decreases, the demands placed on the resist material used increase, both in terms of sensitivity and line roughness. In 2007, according to today's planning, only line roughness of less than 4 nm can be tolerated.

After exposure, the resist systems are subjected to a thermal treatment (post exposure bake, PEB). The known chemically amplified resist systems (CAR) have the problem that the free positively charged parts of the resist system (protons) diffuse isotropically through the resist system. This diffusion effect leads to inaccuracies in the structures to be developed and significantly leads to line roughness.

It is known to limit the diffusion of the positive charged parts by adding bases in order to reduce the line roughness. However, the addition of bases means that the exposure dose has to be increased so that the throughput of the system is reduced.

With the exposure dose remaining the same and the exposure wavelengths becoming shorter and shorter, the number of photons per exposure becomes ever smaller, and with it the number of photoacids generated. Loss of photoacids due to added bases during production would further limit the throughput of products (eg wafers). The present invention has for its object to provide a method with which the lateral diffusion of charged and / or polar components of a resist system is reduced or prevented.

This object is achieved according to the invention by a method with the features of claim 1.

In the method according to the invention, after the resist system has been exposed to a substrate, the resist system is exposed to at least one electrical field. As a result, a force is exerted on charged and / or polar components of the resist system, so that the isotropic diffusion movement of the charged components is superimposed by a targeted movement based on the electric field. Through the

The choice of field strength and / or field direction can be used to influence the movement of the polar and / or charged particles, so that the influence of diffusion e.g. can be reduced in the lateral direction.

It is advantageous if at least one electric field is constant in time and space and is homogeneous in the area of the resist system. The polar and / or charged components of the resist system can thus be oriented in the resist system in a homogeneous manner.

It is also advantageous that the at least electric field has a predetermined gradient and / or is designed as an alternating electric field. Even with such a design, the movements of polar and / or charged components of the resist system can be influenced in a targeted manner.

At least one electric field is advantageously designed as a rotating field (rotating field). It is particularly advantageous if the electrical field vector of the at least one rotating field is a plane perpendicular to a resist system and / or a wafer. If the field vector defines a plane perpendicular to the surface, ie the axis of rotation of the field is parallel to the resist system or substrate, then the diffusion zone is deformed into a flattened ellipsoid due to the preferred plane now present. The superimposition of these changed diffusion zones leads to a further increased effective overlap at the edge of exposed structures.

Furthermore, it is advantageous if at least one homogeneous electric field, a gradient field and / or an alternating field has an angle of less than 90 ° to a resist system and / or the substrate.

It is particularly advantageous if at least electrical

Field is aligned substantially perpendicular to the substrate. This suppresses lateral diffusion of the charged and / or polar components of the resist system; the components are oriented essentially vertically, which is advantageous for producing sharp, vertical lines in the resist.

The line roughness is advantageously reduced if the field strength of at least one electrical field is less than 10 ⁵ V / cm.

In a further advantageous embodiment of the resist system, the resist system is exposed to at least one electrical field during a thermal treatment (e.g. baking of the resist system). It is advantageous if, after the thermal treatment, the electric field or the electric fields is or are switched off and the resist system is treated with a developer solution.

The exposure can advantageously be carried out using a mask process or a direct write process, in particular an e-beam or ion beam method.

The method according to the invention can advantageously be used if the resist system is designed as a chemically reinforced system.

An advantageous embodiment of the method according to the invention uses a resist system with at least one polymer or copolymer with at least one acid-labile group. Such a resist system can surprisingly be structured at wavelengths in the range from 0.1 to 150 nm. The acid labile groups are cleaved under the catalytic action of acid and release polar groups which then increase the solubility of the polymer / copolymer in developers, e.g. cause aqueous alkaline developers.

It is advantageous if at least one acid-labile group is an ester group or a lactone group.

By using a copolymer with at least one maleic anhydride segment and at least one methacrylate segment, a substrate can be used in a lithography process even without chemical reinforcing agents

Wavelengths in the range from 0.1 to 150 nm can be structured. The resist system according to the invention has a large process window since, even at high exposure doses, no crosslinking occurs, which leads to an insolubility of the resist. Even if one generally strives to use small exposure doses, the resist system according to the invention is less sensitive to fluctuations in the exposure due to the large process window.

It is particularly advantageous if a t-butyl methacrylate and / or a 2-ethoxyethyl methacrylate is used as the methacrylate segment. The sensitivity of the resist system can be improved if an iodine-containing and / or sulfur-containing photoacid generator is used as a chemical reinforcing agent.

In an advantageous embodiment of the resist system according to the invention, at least one photo acid generator has a perfluoroalkanesulfuonate anion of the form C _n F _{2n + 1} - _x H _x S0 ₃ ^" with n = 1, ..., 10.

At least one photoacid generator advantageously has an iodonium compound. It is particularly advantageous if at least one photoacid generator has a di (tert-butylphenyl) iodonium triflate, di (tert-butylphenyl) iodonium hexaflate, di (tert-butylphenyl) iodonium nonaflate, diphenyliodonium triflate, diphenyliodonium hexafatone or diphenylafonate.

It is also advantageous if at least one photo acid generator has a sulfonium compound, in particular a triphenylsulfonium triflate, triphenylsulfonium hexaflate or triphenylsulfonium nonaflate.

The resist system according to the invention advantageously has a proportion of silicon, which leads to improved etching stability. It is particularly advantageous if the silicon can be introduced into the resist system in the form of a compound having a polymerizable carbon-carbon bond, in particular a trimethylallylsilane.

The sensitivity is increased if, in the process according to the invention, a resist system with a chemical reinforcing agent which contains at least one iodine and / or contains sulfur-containing photo acid generator is used.

The large process window is evident from the fact that the exposure dose in the lithography process according to the invention can be between 0.1 and 300 mJ / cm ² . Even massive overexposure (e.g. by a factor of 250) does not lead to crosslinking of the polymer in the resist system. It is particularly advantageous if the exposure dose during exposure is between 0.5 and 10 mJ / cm ² .

An embodiment of the method according to the invention can be carried out at a wavelength of 0.1 to 150 nm. This covers the EUV range up to the X-ray range. It is particularly advantageous to use a wavelength of 13.4 nm.

The object is also achieved by a device with the features of claim 29.

By using a means for generating an electric field and at least one receiving means for a substrate with a resist system, it is possible to expose the resist system to the electric field in order to cause the movement of charged and / or polar components of the

To influence resist systems.

In an advantageous embodiment, the means for generating an electric field is part of a device for thermal treatment of the resist system, e.g. a chamber for a baking step.

The invention is explained in more detail below with reference to the figures of the drawings using several exemplary embodiments. Show it: Fig. 1 is a schematic representation of the known resist development process;

2 shows a schematic illustration of a first embodiment of the method according to the invention;

Fig. 3 is a schematic representation of a second

Embodiment of the method according to the invention;

4A, 4B show the diffusion behavior in the

Resist system without (a) and with an electric field (b).

5 shows a schematic representation of a device for carrying out the method according to the invention;

Fig. 6 contrast curves for different resist systems.

In Fig. 1 is a known method for creating structures on a substrate 2, e.g. represented a wafer. The arrow on the left indicates successive process steps.

A substrate 2 is here chemically reinforced

Resist system 1 coated and then exposed with an exposure source 30, which has a mask. The mask structure forms in the resist system 1 as a latent image, which is indicated in FIG. 1 by streaking in the resist system 1. Alternatively, the structure can be created using direct writing methods, e.g. an e-beam or an ion beam method.

The resist system 1 with the latent image of the mask is subjected to a thermal treatment step (PEB). During this step, the known processes lead to an undesired isotropic diffusion of the polar acid (Photo Acid Generator: PAG; photo acid generator) with a polar carboxylic acid group. The isotropic diffusion is described in more detail in Fig. 3a.

After the thermal treatment step, the resist system is treated with a development solution in which vertical structures are retained, but which have a high line roughness due to the lateral part of the isotropic diffusion.

The method according to the invention, which is shown schematically in FIG. 2, is intended to avoid this roughness.

The basic sequence corresponds to the method according to FIG. 1. However, during the thermal

Treatment step of the PEB applied an electric field 10, which is perpendicular to the resist system 1 and the substrate 2. The electrical field 10 is designed here as a time-constant field with high homogeneity. The field direction can point up or down, which is symbolized here by an arrow.

Due to the orientation of the electric field, a force is exerted on polar and / or charged components of the resist system 1 (e.g. PAG) along the field lines, so that the isotropic diffusion movement is superimposed by a vertical movement. As a result, the lateral movement is restricted.

In alternative embodiments, the orientation of the electrical field can also be designed differently. The fields can thus lie at an angle to the resist system 1.

The electrical field 10 can also be designed as a rotating field. This is shown in FIG. 3, FIG. 3 being analogous to the arrangement of the field in FIG. Also by the rotating field, an alignment of the Diffusion zones reached. Furthermore, different fields can also be overlaid, in particular also temporally.

This is shown schematically in FIG. 4. 4A and 4B represent sections from a region of the resist system 1. In FIG. 4A, the movements of the polar and / or charged components of the resist system 1 are represented by circles 40. The circles 40 are to be understood here as sectional representations, since the isotropic diffusion region is spherical.

This corresponds to the isotropic diffusion of the components, which has considerable lateral components. The line roughness, shown in Fig. 3a by the thick line on the left edge, is high.

The application of an electrical field 10 according to the invention has the effect that the isotropic diffusion is overlaid by a drift movement of the charged and / or polar components of the resist system 1. The movements of the

Components are distorted into a kind of ellipse 41 in the two-dimensional representation of FIG. 4B, the region having an ellipsoidal shape in spatial terms.

The vertical movement components are now larger than the lateral ones. The superimposition of these deformed diffusion areas leads to a more effective overlap at the edge of exposed structures. This means that the line roughness, symbolized by the thick line drawn on the left edge, is reduced.

5 schematically shows an embodiment of a device according to the invention. A wafer is arranged as substrate 2 in a device for thermal treatment 20. The substrate 2 is here with a

Resist system 1 coated, which has polar and / or charged components. A means 50a, 50b for generating an electric field 10, which essentially functions like a capacitor, is arranged in the device for thermal treatment. The substrate 2 with the resist system 1 is arranged between the capacitor plates 50a, 50b such that the field lines are perpendicular to the resist system 1. If the capacitor plates 50a, 50b are sufficiently large, the electric field is homogeneous, so that the field lines are parallel and produce the desired parallel drift movement, which was described in connection with FIG. 4B. The field is oriented from top to bottom in FIG. 5.

In the following, resist systems 1 are described which can be used as embodiments in the method and the device according to the invention. In principle, the method according to the invention can be carried out with all chemically amplified resist systems. In the following, reference is made to a group of resist systems by way of example.

The resist system described here has a polymer as part of the resist system, the polarity of which can be changed in a targeted manner. The following describes the production of a polymer, which can then be used alone or together with photo acid generators as a resist system.

The polymer is synthesized using radical polymerization. To do this

20.27 g (206 mmol) maleic anhydride,

26.46 g (186 mmol) t-butyl methacrylate, 3.27 g (21 mmol) 2-ethoxyethyl methacrylate,

0.64 g (4 mmol) of α, α 'azoisobutyronitrile as radical initiator and

0.32 g (2 mmol) dodecyl mercaptan as chain regulator in

41.0 g (52 ml) of 2-butanone dissolved and refluxed for 3 hours heated to boiling (80 ° C). Then 4.0 g (5 ml) of methanol (for partial alcoholysis of the anhydride) are added and the reaction solution is refluxed for a further 24 hours (80 ° C.).

The reaction solution is allowed to cool to room temperature and 35.0 g (27.5 ml) of 2-propanol are added with vigorous stirring. The solution obtained is dissolved in a solution of 10.5 g (13.1 ml) of 2-butanone, 337.0 g (429 ml) of 2-propanol and 329.0 g (329, 0 ml) of water.

The polymer precipitates as a fine, white powder. The mixture is left to stir for a further 30 minutes and then the solvent is suctioned off under a slightly reduced pressure over a G3 frit.

The white precipitate is washed with a solution of 16.0 g (20.0 ml) 2-butanone, 111.0 g (141 ml) 2-propanol and 100.0 g (100 ml) water and for 72 hours at 80 ° C dried in a high vacuum. About 38 g (75% of theory) of fine, white powder are obtained as the reaction product. The analysis can be carried out by means of NMR, GPC or DSC.

A section of a structure is shown below as an example of a silicon-containing polymer of the resist system according to the invention:

Alternatively, a silicon-free polymer can be used:

Example 1 (Resist system with polymer without PAG)

5 g of the polymer described above are dissolved in 209 g of 1-methoxy-2-propyl acetate. The solution is then pressure filtered through a Teflon filter with 0.2 μm pores. After a rest period of 24 hours, a first embodiment of the resist system is ready for use. This first embodiment has no photo acid generator.

The resist system is spun onto a silicon wafer (wafer) at 1000-5000 rpm and baked for 90 s at 130 ° C (PAB). The layer thickness of the resist system is approximately 110 nm after spinning on at 3000 rpm. The exposure is carried out with EUV light of the wavelength 13.4 nm. The exposure dose D ₀ is 36.8 mJ / cm ² . After exposure there is a further baking step, for 90 s at 130 ° C (PEB). Development takes place in a 2.38% tetramethylammonium hydroxide solution, then the wafer is rinsed with distilled water and dried.

The effectiveness of this resist system, even without photo acid generators, is clear from FIG. 1.

6 shows points of three contrast curves in which the film thickness in nm is plotted against the exposure dose in mJ / cm ² . The right curve ("without PAG") shows the measured values of Example 1. Even without a photo acid generator, exposure down to exposure doses down to 10 mJ / cm ^{2 is} possible. The sensitivity is therefore in a range that can be used in practice.

Example 2 (resist system with Di (tert.

Butylphenyl) iodonium hexaflate as photo acid generator)

Basically, iodonium compounds have a structure (IR ₂ ) X, where R can be an organic radical, in particular an aryl group. X is a hydroxy group or a monovalent acid residue. Possible structures are, for example:

Whereby substituents R can also be arranged on such a structure:

Straight or branched alkyl groups, such as —CH ₃ , C ₂ H ₅ , isopropyl or, for example, can serve as substituents R.

CH ₃

-C-CH ₃

CH ₃

The substituents R can be identical or identical to one another. As the anion, the photo acid generator can have, for example, a perfluoroalkanesulfuonate of the form C _n F _{2n +} ι-χH _x S0 ₃ ^" with n = 1, ..., 10.

In the first exemplary embodiment, 50 mg of di (tert-butylphenyl) iodonium hexaflate [(tBu-Ph) ₂ J ⁺ , CF ₃ CHF CF ₂ S0 ₃ ^" ] are added to the polymer according to Example 1 as iodonium compound in 209 g of l-methoxy- 2-propyl acetate dissolved.

The solution is then pressure filtered through a Teflon filter with 0.2 μm pores. After a rest period of 24 hours, a first embodiment of the resist system is ready for use.

The resist system is spun onto a silicon wafer (wafer) at 1000-5000 rpm and baked for 90 s at 130 ° C (PAB). The layer thickness of the resist system after spin-coating at 3000 rpm is approximately 110 nm. The exposure is carried out with EUV light of the wavelength 13.4 nm. The exposure dose D ₀ is 1.4 mJ / cm ² . After exposure, there is a further baking step, 90 s at 130 ° C (PEB). The development takes place in a 2.38%

Tetramethylammonium hydroxide solution, then the wafer is rinsed with distilled water and dried.

A second embodiment of the resist system according to the invention is thus produced. Example 3 (Resist system with triphenylsulfonium nonaflate as photo acid generator)

The photo acid generator can also have sulfonium compounds which basically have the form [R ₃ S] ⁺ X ^~ . A possible structure is, for example, a triphenyl sulfonium (TPS):

The aromatic components may also have the substituents R listed in the example above.

A third embodiment of the resist system according to the invention is produced analogously to Example 2, but triphenylsulfonium nonaflate [Ph ₃ S ⁺ , CF ₃ (CF ₂ ) ₃ S0 ₃ ^" ] is used instead of di (tert-butylphenyl) iodonium hexaflate as the photoacid generator. The exposure dose is 2.4 mJ / cm ² in this exemplary embodiment.

Example 4 (Resist system with triphenylsulfonium nonaflate and

Base)

A fourth embodiment of the resist system according to the invention is produced analogously to Example 3, but 3 mg of triphenylsulfonium acetate are additionally added as the base to the solution. The exposure dose is 4.1 mJ / cm ² . The contrast behavior of this embodiment is the middle curve in FIG. 6 ("PAG + Base"). The sensitivity is also maintained by adding small amounts of base, even if the sensitivity is lower than in the curve on the left in FIG. 6, ie when using a polymer according to the invention with PAG without base.

Example 5 (resist system with diphenyl iodonium triflate)

In a fifth exemplary embodiment, a resist system is produced analogously to Example 2, diphenyliodonium triflate [Ph ₂ J ⁺ , CF ₃ SO ₃ ^~ ] being used as the photoacid generator instead of the di (tert-butylphenyl) iodonium hexaflate. The exposure dose is 1.3 mJ / cm ² .

Example 6 (Resist system with triphenylsulfonium triflate)

In a sixth exemplary embodiment, a resist system is produced analogously to Example 2, triphenylsulfonium triflate [Ph ₃ S ⁺ , CF ₃ S0 ₃ ^~ ] being used as the photo acid generator instead of the di (tert-butylphenyl) iodonium hexaflate. The exposure dose is 0.8 mJ / cm ² .

The left curve in FIG. 6 shows a contrast curve that was determined with a resist system according to this exemplary embodiment. This makes it clear that the photo acid generator significantly improves the sensitivity, so that good results are achieved even with small exposure doses.

However, a much higher exposure dose of 250 mJ / cm ² can also be used. The resist system works even at these high doses without causing undesirable cross-linking. Example 7 (Resist system with triphenylsulfonium hexaflate)

In a seventh exemplary embodiment, a resist system is produced analogously to Example 2, with iodonium hexaflate as the photo acid generator instead of the di (tert-butylphenyl) iodonium

Triphenylsulfonium hexaflate [Ph ₃ S ⁺ , CF ₃ CHF CF ₂ S0 ₃ ^~ ] is used. The exposure dose is 1.6 mJ / cm ² .

Examples 2 to 7 listed show some combinations of the photo acid generators. Basically, are possible

Permutations of the triphenylsulfonium, diphenyliodonium and di (tert-butylphenyl) iodonium salts of trifluorosulfonic acid (triflate), hexafluorosulfonic acid (hexaflate) or nonafluorosulfonic acid (nonaflate) are suitable.

The embodiment of the invention is not limited to the preferred exemplary embodiments specified above. Rather, a number of variants are conceivable which make use of the method and the device according to the invention even in the case of fundamentally different types.

LIST OF REFERENCE NUMBERS

1 resist system

2 substrate

10 electric field

20 Thermal treatment device

30 exposure source

40 isotropic diffusion

41 diffusion superimposed by an electric field

50a, b means for generating an electric field, capacitor plates

Claims

claims

1. A method for treating a resist system for the production of a semiconductor component, the resist system having polar and / or charged components, characterized in that after the resist system (1) has been exposed to a substrate (2), the resist system (1) has at least one electrical component Field (10) for influencing the movement of the polar and / or charged components of the resist system (1) is exposed.

2. The method according to claim 1, characterized in that at least one electric field (10) is constant in time and space and is homogeneous in the region of the resist system (1).

3. The method according to claim 1, characterized in that at least one electric field

(10) has a predetermined gradient and / or is designed as an alternating electrical field.

4. The method according to claim 1 or 3, characterized in that at least one electric field (10) is designed as a rotating field.

5. The method according to claim 4, characterized in that the electrical field vector of the at least one rotating field defines a plane perpendicular to a resist system (1) and / or a wafer.

6. The method according to at least one of claims 1 to 4, characterized in that at least one homogeneous electric field, a gradient field and / or an alternating field has an angle less than 90 ° to a resist system (1) and / or the substrate.

7. The method according to at least one of the preceding claims, characterized in that at least one electric field (10) is oriented substantially perpendicular to the substrate (2).

8. The method according to at least one of the preceding claims, characterized in that the field strength of at least one electrical field (10) is less than 10 ⁵ V / cm.

9. The method according to at least one of the preceding claims, characterized in that the resist system (1) is exposed to at least one electric field (10) during a thermal treatment, in particular a baking step.

10. The method according to claim 9, characterized in that after the thermal treatment, the electrical field (10) or the electrical fields (10) is switched off and the resist system is treated with a developer solution.

11. The method according to at least one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the

Exposure takes place with a mask process or a direct writing process, in particular an e-beam or ion beam process.

12. The method according to at least one of the preceding

Claims, characterized in that the resist system (1) is designed as a chemically reinforced system.

13. The method according to at least one of the preceding claims, characterized in that the Resist system (1) has at least one polymer or copolymer with at least one acid-labile group.

14. The method according to claim 10, characterized in that at least one acid-labile group of the resist system is an ester group or a lactone group.

15. The method according to claim 13 or 14, characterized by a resist system (1) with a copolymer with at least one maleic anhydride segment and at least one methacrylate segment.

16. The method according to claim 15, characterized in that the methacrylate segment is a t-

Butyl methacrylate and / or a 2-ethoxyethyl methacrylate.

17. The method according to at least one of the preceding claims, characterized by a resist system (1) with at least one iodine and / or sulfur-containing photoacid generator as a chemical reinforcing agent.

18. The method according to claim 17, characterized in that at least one photo acid generator has a perfluoroalkanesulfuonate anion of the form C _n F _{2n +} ι-χH _x S0 ₃ ^~ with n = 1, ..., 10.

19. The method according to claim 17 or 18, characterized in that at least one photoacid generator has an iodonium compound.

20. The method according to at least one of claims 17 to 19, characterized in that at least one photoacid generator is a di (tert-butylphenyl) iodonium triflate, di (tert-butylphenyl) iodonium hexaflate, di (tert.

Butylphenyl) iodonium nonaflate, diphenyliodonium triflate, Diphenyliodoniumhexaflat or Diphenyliodoniumnonaflat has.

21. The method according to at least one of the preceding claims, characterized in that at least one photoacid generator has a sulfonium compound.

22. The method according to claim 21, characterized in that at least one photo acid generator

Triphenylsulfonium triflate, triphenylsulfonium hexaflate or triphenylsulfonium nonaflate.

23. The method according to at least one of the preceding claims, characterized by a portion

Silicon.

24. The method according to claim 23, characterized in that the silicon can be introduced into the resist system in the form of a compound with a polymerizable carbon-carbon bond, in particular a trimethylallylsilane.

25. The method according to at least one of the preceding claims, characterized in that the polymer before the application of the resist system (1) with a chemical reinforcing agent which is mixed at least one iodine and / or sulfur-containing photoacid generator.

26. The method according to at least one of the preceding

Claims, characterized in that the exposure dose during exposure is between 0.1 and 300 mJ / cm ² .

27. The method according to at least one of the preceding claims, characterized in that the Exposure dose during exposure is between 0.5 and 10 mJ / cm ² .

28. The method according to at least one of the preceding claims, characterized in that the

Wavelength during the exposure is 0.1 to 150 nm, in particular 13.4 nm.

29. Device for carrying out the method according to claim 1,

marked by

a means for generating at least one electric field (10) and at least one receiving means for a substrate (2) with a resist system (1).

30. The device according to claim 29, characterized in that the means for generating an electric field (10) is part of a device for thermal treatment of the resist system (1).