WO2003054630A2

WO2003054630A2 - Device and method for modifying the surface of a workpiece using photonic radiation

Info

Publication number: WO2003054630A2
Application number: PCT/AT2002/000354
Authority: WO
Inventors: Dieter BÄUERLE; Klaus Piglmayer
Original assignee: Austria Wirtschaftsservice Gesellschaft mit beschränkter Haftung
Priority date: 2001-12-21
Filing date: 2002-12-18
Publication date: 2003-07-03
Also published as: AT411755B; AU2002361370A8; ATA20192001A; WO2003054630A3; AU2002361370A1; WO2003054630A8

Abstract

The invention relates to a device and a method for modifying the surface (1') of a workpiece using photonic radiation (2), especially laser radiation. Said device comprises a radiation source (3) and a mask device, said mask device being configured by a support (7), permeable to the radiation (2), to whose side facing the workpiece (1) individual lens elements (9) are adhered and the radiation (2) is bundled into partial beams (10) by the individual lens elements (9).

Description

Device and method for modifying a workpiece surface using photon radiation

The invention relates to a device for modifying a workpiece surface with the aid of photon radiation, in particular laser radiation, with a radiation source and a mask device for the radiation.

In a corresponding manner, the invention relates to a method for modifying a workpiece surface with the aid of photon radiation, in particular laser radiation, which is directed onto the workpiece surface via a mask device.

The processing of materials in the um range and nm range, often called "micro- or nanostructuring", is becoming increasingly important in technology, with so-called optical lithography in particular becoming an interesting area of application in the course of miniaturization in microelectronics is. In addition to electron and ion beam techniques, laser beam technology is also being used more and more frequently here, since it is less expensive in terms of apparatus and money to implement than electron and ion beam techniques. Laser beam technology also offers further advantages, such as, in particular, the type of structuring of the workpiece surface, based on the properties of the laser radiation itself. In this way, photochemical and photothermal deposition and ablation from the surface as well as photophysical deposition of material on the surface (so-called forward transfer) and photophysical ablation or ablation can be accomplished. However, as with electron beam technology, a problem here is that single-step machining with a single beam results in low efficiency. For industrial use, the production of large quantities in a short time would be required, i.e. greater throughput would be desirable.

Mask techniques for micro- and nanostructuring have already been implemented, which often require more than ten complex individual steps, but several structuring can be carried out in parallel. The individual steps can be complex. In detail, the known devices (for example according to R. Völkel et al., "Microlens Lithograph phy and Smart Masks ", Microelectronic Engineering, Vol. 35, 1997, pp. 513-516; JP 5224396 A; and US Pat. No. 6,107,011 A) always about first achieving certain structures in a photoresist layer via an optical lens system, which means that the actual mask device is formed by the photoresist layer. In order to expand the structuring of the imaging field, a lens array with a plurality of individual lens elements is used as the lens system, this lens system, however, being separate from the actual mask structure. to process the respective workpiece surface directly, but rather to produce a mask for a standard multi-step process for structuring, which is only to be carried out afterwards, with low-intensity radiation being used for the exposure of the photoresist layer in the mask production Ä etching steps and rinsing steps necessary to obtain the mask required for the final workpiece modification. The masks produced in this way in a complex manner are also irreversible in nature.

It would be desirable to combine the high throughput of a mask process with the universal possibilities of a single-step machining process.

Certain periodic structures can be generated using photon beams, in particular laser beams, using interference effects. However, this requires a high level of technological effort, and these interference techniques can only be used to a limited extent. In addition, the degree of miniaturization is limited by the wavelength of the radiation used.

In the article by U. Brauch et al., "Optical lithography - a key technology of microstructuring", Laseropto No. 4, Aug. 2000, pp. 59-66, a technique of bundling light by glass fiber tips is proposed, the dimension the glass fiber tips is smaller than the wavelength used in order to achieve a radiation beam in a small area. However, the effort associated with the use of these fine glass fiber tips is very high and the possible uses, particularly in the case of structured processing, are limited. Due to the mechanical dimensions and the dimensions of the glass fiber tips, the desired high number of miniaturized limited illustrations (processing).

It is an object of the invention to provide a device or a method as mentioned above, with which a parallel connection of many single-step processes leading to a high throughput can be achieved while providing the universal possibilities of a single-step machining process.

It is a further object of the invention to develop such a technique which is associated with a comparatively small outlay in terms of apparatus and costs. Furthermore, it is an object of the invention to enable a high degree of adaptation in the various machining processes or general modifications of the workpiece surface - removal as well as material deposition.

The device according to the invention of the type mentioned at the outset is accordingly characterized in that the mask device is formed by individual lens elements which are attached to a carrier which is permeable to the radiation, preferably on its side facing the workpiece, the radiation being able to be bundled into partial beams by the individual lens elements ,

In a corresponding manner, the method according to the invention of the type mentioned at the outset is characterized in that the radiation is divided into partial beams with the aid of individual lens elements provided as a mask device and attached to the radiation-permeable carrier, which are bundled into individual focal points.

In the technique according to the invention, therefore, a special mask device is used, which can also be referred to as a lens device, and in which small bodies are applied as lens elements in a certain, orderly manner on a carrier which is transparent to the radiation, in particular with regard to the short focal distances - on the side of the carrier that faces the workpiece during operation. Each body forms a single lens element through which the respective part of the radiation impinging on the carrier is bundled into a partial beam with a single focal point. As a result, a large number of focus points are obtained which can be used for the desired machining or modification of the workpiece surface, for example the surface of a semiconductor body. If the workpiece surface is brought into the plane in which the focal points lie, multiple processing with quasi-individual beams for the removal of material etc. can be achieved, with material of the workpiece or substrate locally, for example, in the range of nm , can be removed by evaporation.

The invention is based on an effect that has been shown in studies on laser-assisted cleaning of workpiece surfaces, in which contamination on the surface of a workpiece was simulated by small beads, for example with a diameter of less than 100 nm Experiments have shown that the smaller the beads, the more problematic the removal of the beads from the surface, and that these beads, when they are made of an optically transparent material, bundle the incident radiation in a comparable way to lens elements. In laser-assisted cleaning of surfaces, this leads to undesirable phenomena: in many cases, holes are formed in the surface material to be cleaned, since the focus of the radiation by the beads locally evaporates the absorbent material before the beads are flung away. Apart from the cleaning effect, the substrate is damaged. The invention now uses this effect in a positive manner in that the focusing effect of the spheres or, in general, individual lens elements are used specifically for surface treatment. The individual lens elements are attached to the carrier in an array in accordance with the desired processing pattern. The carrier is preferably an optically plane-parallel plate which is transparent to photon radiation, for example made of normal glass, quartz glass, etc. On the side of this plate facing the workpiece or substrate, the individual lens elements are preferably in a single layer, ie in a monolayer , applied. The individual lens elements are in particular small spheres, ellipsoids, that is to say quasi flattened spheres, small cylinders or the like, and they consist, for example, of normal glass, quartz glass or another material which is transparent to the photons, such as Si, CaF ₂ , organic polymers, for example polystyrene, or also from organic materials or conglomerates such as bacteria or viruses etc. The entire arrangement is thus highly transparent. at Irradiation with photon radiation, in particular laser radiation, from the carrier side, the arrangement acts like a combination of a large number of. more or less closely adjacent focusing lenses. The incident radiation passes through the carrier and is focused by the individual lens elements, the particular focus being somewhat outside the individual lens element, for example at a distance of approximately 20% of the radius in the case of spherical individual lens elements.

As such, the surface to be processed can be brought into direct contact with the single lens element matrix, which makes it particularly easy to implement _. leads. The "mask device" only needs to be placed on the workpiece and irradiated from above. Of course, high-purity working conditions and surfaces are desirable.

The spherical or ellipsoidal individual lens elements can be in a maximally dense packing, corresponding to a pattern in which the centers of adjacent, contacting individual lens elements form the corner points of equilateral triangles. The dimensions of the individual lens elements are in the order of magnitude of 100 nm or less up to a few μm, and the processing points on the substrate have dimensions in the nm to μm range.

The individual lens elements normally adhere sufficiently to the support through natural adhesion. However, the liability of the individual lens elements can be increased by external forces, such as in particular by applying an electrical voltage between the carrier and the workpiece. The distance between the carrier and the individual lens elements from the workpiece or substrate can be fixed, wherein one or more spacers can be applied to the carrier. For example, local material deposits can be provided as spacers by vapor deposition, in particular by vapor deposition of a thin local metal layer, or by attaching a thin film (plastic, metal). A three-point spacer with measurement and adjustability, based on piezoelectric transducer elements, is ideal for variable or adjustable adjustment of the distance, especially in the case of critical materials to be processed, such as plastic films.

The present technique can also be of great advantage for surface modification by so-called laser-induced Forward transfer (LIFT - Laser Induced Forward Transfer) can be used. This LIFT technique has already been described for an arrangement with a single lens, see Z. Kantor et al., "Deposition of micrometer-sized tungsten patterns by laser transferred technique" Appl. Phys. Lett. 64 (25), June 20, 1994, pages 3506-3508. The combination with the present multiple lens arrangement enables a very simple and highly localized multiple metallization of surfaces, which can be carried out in a normal laboratory atmosphere (without the use of chemicals and gases). In this technique, a thin layer of material, in particular an ultra-thin metal foil, is applied between the substrate to be processed and the carrier with the individual lens elements, it being possible for the foil to be applied to the substrate by means of magnetic or electrostatic force, depending on the metal used; the carrier with the individual lens elements can then be placed thereon, possibly with spacing using the spacers mentioned. The distance is chosen so that the individual lens elements focus the radiation in focal points within the thin metal foil or material layer in general. As a result, the smallest metal parts are transferred locally in the direction of the substrate, where they adhere. After this processing, the film can simply be stripped off the substrate (workpiece).

In order to achieve a high degree of uniformity of the individual processing points on the substrate, apart from the same dimensions of the individual lens elements and a uniform distance from the substrate surface, a laser radiation that is homogeneous over its cross section is also required if it strikes the individual lens elements on the outside of the carrier. Accordingly, it is advantageous if the radiation is homogenized in a manner known per se with the aid of a homogenizer, so that the radiation has an essentially constant intensity over the entire cross-section of the radiation beam.

When machining or generally modifying the workpiece surface, the workpiece can be moved relative to the carrier with the individual lens elements in the xy directions of its surface in a conventional manner in order to enable multiple lithography processing. Furthermore, depending on the processing to be carried out, it is also conceivable if some of the Individual lens elements can be hidden by shading with a mask provided in front of the wearer.

The invention is explained in more detail below on the basis of preferred exemplary embodiments, to which, however, it should not be restricted, and with reference to the accompanying drawing. This drawing shows in detail:

1 schematically shows a preferred device for carrying out nanostructuring machining of a workpiece surface with the aid of laser radiation;

FIG. 2 shows a schematic plan view of a lens array with spherical or ellipsoidal individual lens elements which are circular in plan view, as used in the arrangement from FIG. 1;

3 shows schematically in a view or sectional view the mode of operation of various individual lens elements with regard to the focusing of individual or partial beams caused by them, part of the substrate with local ablation being shown in section in FIG. 3a, and FIG. 3b contains a schematic representation showing the local ablation of the substrate in a top view of FIG. 3a;

4 shows an arrangement of a transparent plane-parallel plate with individual lens elements at a distance from a substrate, in an arrangement within a chamber which contains a predetermined gas atmosphere and which has an entry window for the laser radiation;

5 schematically shows a part of a device (without radiation source) for illustrating a so-called laser-induced material forward transfer;

FIG. 6 shows a view of the substrate with metallic deposits attached to it with the aid of a device according to FIG. 5, with a partially pulled-off metal foil;

7 is a top view of a portion of a substrate at approximately 5000X, illustrating local ablations on the substrate surface; and

8 shows an electron microscope image of a substrate surface in a magnification of approximately 23,000 times, to illustrate a deposited aluminum double structure.

1 illustrates a device for modifying the surface of a substrate or workpiece 1 with the aid of laser radiation (generally photon radiation) 2 from a radiation source 3, such as an excimer laser. The radiation emitted by the radiation source 3 can have an inhomogeneous intensity over its cross section (diameter D), as shown in a detailed drawing at 4 in FIG. 1, and in order to achieve a homogeneous radiation intensity for processing the surface of the substrate 1 a homogenizer 5 is provided which forms a component which is known per se and which, via reflections on its inner wall, leads to a homogeneous intensity distribution in the radiation beam 2, as shown in FIG. 1 in detail drawing 6 for the diameter D '. Of course, the diameter D 'can be equal to the radiation beam diameter D.

The homogenized radiation strikes a single lens element carrier 7 in the form of a plane-parallel plate 8 made of glass, in particular quartz glass, which is transparent to the radiation. This plate 8 is provided on its side facing the substrate 1 with a plurality of individual lens elements 9 which adhere to the plate 8 by natural adhesion in an arrangement adapted to the respective processing of the surface 1 'of the substrate 1. A maximally dense arrangement of spherical or, in plan view, circular, ellipsoidal individual lens elements 9 is used, as can be seen from FIG. 2. These individual lens elements 9 lead to bundles. Partial beams 10, the focal points 11 of which, in the case of processing the surface 1 ', preferably lie in the plane of this surface 1' of the substrate 1, e.g. when removal or ablation of the material is desired at a large number of locations with the smallest dimensions, in the nm range.

In order to determine the arrangement of the individual lens elements 9 at a defined distance from the substrate 1, spacers 12 are provided on the carrier 7, by means of which the carrier 7, that is to say the plate 8, is supported on the substrate surface 1 ′. Such a precisely defined distance is advantageous if ultra-high miniaturization is desired or if structuring is to be carried out in a specific chemical atmosphere (cf. also FIG. 4 explained below). In the ideal case, as mentioned, the depth of focus is equal to the distance of the individual lens elements 9 from the substrate 1.

The spacers 12 can be easily by vapor deposition of thin local metal layers, but also by Sputter deposition, or with the help of piezoelectric ducks. In the latter case, apart from a measuring arrangement for determining the given distance, which is not illustrated in more detail in FIG. 1, a voltage source 13 for applying a voltage U _P to the piezo element spacers 12 can also be used to set the respective optimal distance, in particular to achieve this an exact parallelism of the lens array and the substrate surface 1 '.

The carrier 7 with the individual lens elements 9 can best be compared with a special mask device with which the radiation 2 is focused in large numbers - the focal points 11 - to more or less point-like locations. The individual lens elements 9 are in a single layer, in one. Monolayer, as shown schematically in Fig. 1, attached to the plate 8, to which they adhere as indicated by natural adhesive forces. Of course, the individual lens elements 9 are essentially transparent to the radiation 2 used, and, as already mentioned, they consist of glass, in particular quartz glass. In the case of spheres or ellipsoids, these small bodies have cross-sectional dimensions, i.e. a diameter d (see FIG. 2) on the order of 100 nm (or below) to a few µm. Due to the focusing effect of these individual lens elements 9 with respect to the incident radiation 2, a parallel multiple focusing effect with a practically arbitrarily high number of focal points 11 is achieved. If the substrate 1 is attached with its surface 1 'correspondingly close to the individual lens elements 9, this multiple focusing effect can be used to modify the surface 11', according to FIG. 1 in the form of material removal or ablation. If the substrate 1 is moved up and down in the drawing plane according to FIG. 1 and perpendicular to the drawing plane, see arrow 14 and the circle with point 15 in FIG. 1 at the top left, corresponding patterns in the manner of a lithographic processing can be made in the surface 1 'of the substrate 1 can be inscribed. This results in the enormous potential of a combination of a high parallel throughput rate with the universal properties of the single-step machining process.

For certain patterns of surface modifications, it may be desirable not to bring about focusing over all the individual lens elements 9, but rather to fade out certain areas. to switch off or on; For this purpose, a mask 17, illustrated with dashed lines in FIG. 1, can be arranged in front of the plate 8.

Glass beads such as are commercially available in solutions such as isopropanol can be used as individual lens elements 9. These beads are applied with a micropipette to the high-purity plane-parallel plate 8 in the form of drops. The 40% concentrate of 5 μm beads available as standard allows direct condensation of wide monolayers in the densest arrangement in the range of 0.1 to 0.3 μl. Modifications to the arrangements can be achieved by slightly tilting the surface when the droplet condenses. The production of densest monolayers over large areas has already been investigated specifically for the coating of substrates, cf. e.g. F. Burmeister et al., "Colloid monolayer lithography. A flexible approach for monostructuring of surfaces", Appl. Surface Science 144-145 (1999) 461-466. Any solvent residues are also highly transparent and do not interfere with the passage of radiation through the arrangement.

Structuring distances can be varied by changing the bead diameter. Loose arrangements (single, double and triple structures) are achieved by spinning the solution.

The adhesion of the beads can be influenced by external forces, e.g. by applying a (direct) voltage U between plate 8 and substrate 1. For this purpose, a voltage source 16 is shown in FIG. 1.

With bead diameters of less than 5 μm, the focusing effect can be in the range of the radiation wavelengths used and can therefore be very high. For sphere diameters smaller than approx. 1 µm, the focal plane then moves to a position within the sphere, cf. Fig. 3, left side .. Here, a plastic deformation to lens-like, thinner structures, as it sometimes occurs over longer periods of time, or the use of smaller spheres can put the focal plane (focal points 11) outwards again, cf. Fig. 3, right side.

The distance to the medium to be structured must be set according to the application. The distance of the focus is generally only a fraction of the ball diameter; at 5 um Balls, for example, is approximately 1 μm.

3a shows in a detailed cross-sectional representation that the local ablations can lead to depressions with diameters in the order of a tenth of the diameter of the individual lens elements 9, small craters 18 which are formed within an elevation 19 obtained by the heating lie, cf. also Fig. 3b.

In Fig. 4, the arrangement of the plane-parallel plate 8 with the individual lens elements 9 in spherical shape, which is held at a correct distance from the substrate 1 with the surface __ 'by means of spacers 12, is shown in a closed chamber 20 which has a transparent entrance window 21 for has the radiation 2, in particular laser radiation, which strikes the plate 8 over a correspondingly large area, as also shown in FIG. 1, in order to then use the individual lens elements 9 in the bundled partial beams 10 to the individual focal points 11 to be divided. For example, by absorption of the incident energy in the substrate 1 on the surface 1 ', the high-resolution structuring process in turn occurs, which now takes place in a predetermined reactive gas phase, as indicated very schematically at 22 in FIG. 4. An evacuation outlet 23 and a gas inlet 24 are provided on the chamber 20 to bring about the corresponding gas atmosphere in the chamber 20, the outlet 23 with a vacuum pump (not shown in more detail) and the inlet 24 with a gas source (also not shown in more detail), of course, in each case a valve or the like - is connected.

In principle, however, processing can also be carried out in a liquid instead of in a gas atmosphere; working in an inert environment, generally in a controlled atmosphere, is also conceivable.

The surface 1 ′ of the substrate 1 can, however, not only be modified by such an ablation with the aid of the partial beams 10, but also in that material, in particular metal, is deposited on the surface of the substrate 1. Such a so-called LIFT technique is schematically illustrated in FIGS. 5 and 6, it being evident that, for example, an extremely thin metal foil 25 is attached to the surface 1 'of the substrate. The "mask device" with the plate 8 and the spherical ones is then located above it Individual lens elements 9, with the help of laser radiation 2, the smallest local areas of the metal foil 25 are now detached therefrom and deposited on the surface __ 'of the substrate 1. These smallest metal particle deposits are illustrated at 26 in FIG. 5; the remaining, corresponding holes 26 'having metal foil 25' is then simply stripped off, as illustrated in FIG. 6.

Depending on the metal used, the metal foil 25 can be attached to the substrate 1 magnetically or electrostatically.

Finally, FIG. 7 shows the result of an experiment as a 5000-fold enlargement of a part of a substrate surface __ ', with depressions 18 having a diameter of approximately half a μm at intervals of approximately 5 μm, corresponding to a, made using the technique according to the invention Diameter of the spherical individual lens elements 9 of 5 microns can be seen.

Due to the more complex implementation of chemical deposition and etching processes, the simplest methods of structuring are those that can be carried out in a normal laboratory atmosphere.

The invention is to be explained in more detail below on the basis of two specific exemplary embodiments.

Example 1: Laser-induced ablation:

An excimer laser-induced ablation of PET and PI plastic films in air was carried out as an example, see also the illustration (electron microscope image) in FIG. 7. A 30 ns long laser pulse with a 248 nm wavelength was used and a pulse power of approximately 100 mJ; the individual lens elements 9 were quartz balls of the densest packing, with a ball diameter of 5 μm; spacers 12 of 6 μm thickness were also used.

Example 2:

Material deposition - modified laser-induced forward

Transfer (LIFT):

For this purpose, the metal to be transferred locally was in the form of a very thin film (25 in Fig. 5) applied to a quartz substrate 1: Two different methods were used: Magnetic metals (eg nickel): The film (adjacent) was applied exactly by magnetostatic forces (magnet holder).

Other metals: The metal foils were applied by electrostatic forces; e.g. an aluminum foil of 800 nm thickness was used and a voltage between the foil and the substrate of approximately 1 kV was applied; a laser pulse with a wavelength of 248 nm and an energy of 500 mJ was used as radiation; the individual lens elements were 0.8 μm spheres at the closest distance. FIG. 8 illustrates an electron microscope image of an Al double structure, produced with a double lens structure as such as single lens elements (0.8 μm spheres, directly adjoining one another).

Claims

Claims:

1. Device for modifying a workpiece surface with the aid of photon radiation, with a radiation source and a mask device for the radiation, characterized in that the mask device is provided on a carrier (7) that is transparent to the radiation, preferably on the workpiece ( 1) facing side, adhesively attached individual lens elements (9) is formed, the radiation (2) being able to be bundled into partial beams (10) by the individual lens elements (9).

2. Device according to claim 1, characterized in that the carrier (7) is a plane-parallel plate (8).

3. Device according to claim 1 or 2, characterized in that the carrier (7) consists of glass.

4. Device according to one of claims 1 to 3, characterized in that the carrier (7) consists of quartz glass.

5. Device according to one of claims 1 to 4, characterized in that the individual lens elements (9) consist of glass.

6. Device according to one of claims 1 to 5, characterized in that the individual lens elements (9) consist of quartz glass.

7. Device according to one of claims 1 to 4, characterized in that the individual lens elements (9) consist of silicon.

8. Device according to one of claims 1 to 4, characterized in that the individual lens elements (9) consist of calcium fluoride.

9. Device according to one of claims 1 to 4, characterized in that the single lens elements (9) made of an organic polymer, e.g. Polystyrene.

10. Device according to one of claims 1 to 9, characterized indicates that the individual lens elements (9) are spherical.

11. The device according to one of claims 1 to 10, characterized in that the individual lens elements (9) are cylindrical.

12. Device according to one of claims 1 to 11, characterized in that the individual lens elements (9) are ellipsoidal, their elliptical cross-section with the minor axis is at least substantially rectangular and their circular cross-section is at least substantially parallel to the surface of the carrier (7) ,

13. Device according to one of claims 1 to 12, characterized in that the individual lens elements (9) are mounted in a monolayer on the carrier (7).

14. Device according to one of claims 1 to 13, characterized in that the individual lens elements (9) are arranged on the carrier (7) in dense packing, touching one another.

15. Device according to one of claims 1 to 14, characterized in that the individual lens elements (9) have dimensions in the order of magnitude of approximately 100 nm to a few μm.

16. The device according to one of claims 1 to 15, characterized in that the individual lens elements (9) adhere to the carrier (7) by natural adhesion.

17. Device according to one of claims 1 to 16, characterized by a voltage source (16) for applying an electrical voltage between the carrier (7) and the workpiece (1), for increasing the adhesion of the individual lens elements (9) to the carrier (7) ,

18. Device according to one of claims 1 to 17, characterized in that at least one spacer (12) is attached to the carrier (7) on the side facing the workpiece (1) during operation.

19. The apparatus according to claim 18, characterized in that the spacer (12) is formed by vapor-deposited material, in particular metal, on the carrier (7).

Device according to claim 19, characterized in that several, e.g. three, piezo elements are provided as spacers (12) which are connected or can be connected to an electrical voltage source (23).

21. Device according to one of claims 1 to 20, characterized in that a radiation homogenizer (5) is assigned between the radiation source (3) and the individual lens element carrier (7).

22. Device according to one of claims 1 to 21, characterized in that between the individual lens elements (9) and the workpiece surface (1 '), in particular in the region of the focusing of the partial beams (10), a material transfer layer, e.g. a metal foil (25) is arranged.

23. Device according to one of claims 1 to 22, characterized in that the .Photon radiation is laser radiation.

24. Method for modifying a workpiece surface with the aid of photon radiation (2), which is directed onto the workpiece surface (1 ') via a mask device, characterized in that the radiation (2) is provided with the aid of a mask device , is divided into partial beams (10) on a single lens element (9) attached to the radiation - permeable carrier (7), which are bundled into individual focal points (11).

25. The method according to claim 24, characterized in that the partial beams (10) for ablation of material in individual focus points (11) on the workpiece surface (1 ') are bundled.

26. The method according to claim 24, characterized in that the partial beams (10) for the purpose of material transfer to the workpiece surface (1 ') in the region of a material transfer layer arranged in front of the latter, for example metal foil (25), in single focus. points (11) can be bundled.

27. The method according to any one of claims 24 to 26, characterized in that the distance between the individual lens element carrier (7) and the workpiece surface (1 ') is set with the aid of piezo elements as a spacer (12).

28. The method according to any one of claims 24 to 27, characterized in that the adhesion of the individual lens elements (9) to the carrier (7) by applying an electrical voltage (U) between the carrier (7) and the workpiece surface (1 ') is reinforced.

29. The method according to any one of claims 24 to 28, characterized in that the radiation (2) is homogenized with the individual lens elements (9) before striking the carrier (7).

30. The method according to any one of claims 24 to 29, characterized in that the modification of the workpiece surface (1 ') by ablation or material transfer with the aid of the partial jets in a controlled environment, in particular gas atmosphere (22), is carried out.

31. The method according to claim 30, characterized in that the modification of the workpiece surface (1 ') is carried out in a reactive atmosphere.

32. The method according to any one of claims 24 to 31, characterized in that some of the individual lens elements (9) are hidden by shading with a mask (17).

33. The method according to any one of claims 24 to 32, characterized in that laser radiation is used as photon radiation.