DE102012109130A1 - Method for manufacturing three-dimensional structure used for optic element, involves moving portion of pattern of high-energy region relative to photo-sensitive material, to write structure into photo-sensitive material - Google Patents

Abstract

The method involves irradiating (20) a mask (15) for producing pattern of high-energy region (16). One portion of pattern of high-energy region is moved (21) relative to the photo-sensitive material (17), in order to write a structure into the photo-sensitive material. The photosensitive material is then developed (22) by using suitable chemicals to create a three-dimensional structure. An independent claim is included for device for manufacturing three-dimensional structure.

Description

The present invention relates to the production of three-dimensional structures, in particular the production of microstructures and nanostructures by exposure of a photosensitive material.

The production of three-dimensional structures with structure sizes, in particular in the micrometer range or even in the nanometer range, is interesting for a large number of applications. For example, such three-dimensional structuring can produce optical elements such as optical crystals, optical gratings or polarizing filters.

One way of making such structures is to appropriately expose and develop a photosensitive material, also referred to as a resist, which upon development, for example, exposes exposed parts to leave only unexposed portions.

One possibility for this is the so-called Talbot lithography. In Talbot lithography, a photosensitive bulk material is exposed through a suitably designed mask, with usually no optical elements being arranged between mask and bulk material. An intensity profile of the mask is reproduced at a specific distance from the mask, the so-called Talbot distance, by corresponding superposition of the Fourier modes. As a result, for example, three-dimensional volume lattices can be produced, as described in Seokwoo Jeon; Fabrication complex three-dimensional nanostructures with high-resolution conformable phase masks; PNAS, Vol. 101, no. 34, p. 12,428 to 12,433; 2004, Seokwoo Jeon; Three-dimensional nanofabrication with rubber stamps and conformable photomasks; Advanced Materials, Vol. 16, no. 14, p. 1369-1373; 2004 or Seokwoo Jeon; Fabrication of three dimensional nanostructures using two photon lithographs in a single exposure step; Optics Express, Vol. 14, no. 6, p. 2300-2308; 2006 is described.

This makes it possible to structure substrates over a large area, with only one exposure step is necessary. In the structure to be created, a form of the resulting three-dimensional structure can be influenced by appropriate adaptation of the mask used. However, the production of asymmetrical shapes by means of this Talbot lithography is relatively complicated and requires, for example, a lighting of the mask from different angles.

One way to create virtually any shape is 3D laser beam lithography. Here, a photosensitive bulk material is exposed by means of a laser beam, whereby two-photon processes can be used. The 3D laser beam lithography is, for example, in Justyna K. Gansel; Gold helix Photonic Metamaterial as Broadband Circular Polarizer; Science, Vol. 325, p. 1513-1515; 2009 . MS Rill; Photonic Metamaterial Structures by 3D Laser Writing; OSA / FiO / LS / META / OF &T; 2008 . Alexandra Boltasseva; Fabrication of optical negative-index metamaterials: Recent advances and outlook; Metamaterials, Vol. 2, p.1-17; 2008 or Yong-Lai Zhang; Designable 3D nanofabrication by femtosecond laser direct writing; Nanotoday, Vol. 5, p. 435-448; 2010 described.

In this case, a focused laser beam is used as the only "write head", also referred to as a voxel (volume element). Therefore, in 3D laser beam lithography, fabricating larger structures and processing large area substrates is time consuming because the "write head" must write the entire structure, reducing, for example, manufacturing efficiency of corresponding products.

It is therefore an object of the present invention to provide methods and devices for producing three-dimensional structures, with which, on the one hand, it is possible to produce large structures more time-efficiently than in 3D laser beam lithography and, on the other hand, provides greater flexibility with regard to the shape of the structures than in the case of Talbot lithography.

In this regard, a method according to claim 1 and an apparatus according to claim 13 are provided. The subclaims define further embodiments.

According to one aspect of the invention, there is provided a method of generating a three-dimensional structure, comprising:
Irradiating a mask to generate a pattern of regions whose power density is above a predetermined threshold, and

Moving at least a portion of the pattern of areas in a photosensitive material relative to the photosensitive material to write a pattern in the photosensitive material.

Thus, as it were, by means of the mask, a pattern is generated from regions which serve as "write heads", ie voxels, and with these multiple write heads a desired pattern corresponding to a desired three-dimensional structure is then written into the photosensitive material. It is thus written in parallel with multiple write heads, which allows a higher speed in the processing of large-area substrates such as laser beam lithography, in which only one Stylus is used. The fact that at least a part of the pattern is moved in the photosensitive material is to be understood as meaning that another part of the pattern, ie some areas, may also be outside of the photosensitive material during movement so that only those within the photosensitive material lie Areas of the pattern serve as writing heads.

It should be noted that the definition of areas having a power density above the threshold does not mean that outside the areas, no processes in the photosensitive material are triggered by lighting, but merely indicates that high energy areas (energy above the threshold) exist. The threshold value can be set, for example, as half the maximum power density and depend on a power density before the mask or power density of a light source used.

In particular, in such methods, no optics is needed between the mask and the photosensitive material.

The movement of the pattern of areas through the photosensitive material may in principle take place both by a movement of the photosensitive material and by a movement of the pattern.

The mask may in particular be an amplitude mask or phase mask, for example a sinus mask. In particular, the regions may lie in a Talbot plane and / or a fractional Talbot plane.

Moving the pattern of regions relative to the photosensitive material may, in some embodiments, include moving in a plane parallel to the mask. In other embodiments, the moving may also include three-dimensional moving.

The regions may in particular have a half-width of less than 5 μm, preferably less than 1 μm, the maximum power density within the regions preferably being greater than 1/10 of the power density of an input wavefront hitting the mask, more preferably greater than 0.5 × or 1 × the power density of the input wavefront.

In this case, a wavelength of a radiation used can be chosen such that two or more photon processes occur during writing, which reduces the half-width of the regions and thus increases a possible resolution.

According to another embodiment, there is provided a corresponding apparatus comprising:
a radiation source arrangement, in particular with a light source,
a mask configured to generate a pattern of regions whose power density is above a predetermined threshold when irradiated with radiation from the radiation source;
a receptacle for receiving a photosensitive material, and
a controller for controlling a relative movement between the pattern and a photosensitive material on the photograph to write a pattern in the photosensitive material.

The light source may comprise a laser, in particular a femtosecond short-pulse laser.

By way of example, such a device can be set up by appropriate design of the mask and / or the controller to carry out one or more of the methods described above.

In the following, the present invention will be explained in more detail with reference to the accompanying drawings with reference to exemplary embodiments. Show it:

1 3 is a schematic diagram of a device according to an embodiment of the present invention;

2 a flowchart illustrating a method according to an embodiment of the invention,

3 an example of a mask usable in embodiments of the invention,

4A to 4Q Examples of intensity distributions in embodiments of the invention,

5 Examples of patterns of high-energy areas,

6 Examples of writing a structure in a plane, and

7 an example of writing a three-dimensional structure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. These embodiments serve only the Illustrative of the invention and is not to be construed as limiting, as the invention may be implemented otherwise than illustrated.

Features of various embodiments may be combined with each other unless otherwise specified. On the other hand, a description of an embodiment having a plurality of features is not to be construed as requiring all of these features to practice the invention, as other embodiments may have fewer features and / or alternative features.

In 1 is a device 10 for producing three-dimensional structures according to an embodiment of the present invention. The illustrated embodiment includes a radiation source, in this case a light source 11 which is an optic 13 for generating plane wavefronts 14 with light rays 12 illuminated. The term "light rays" here is not interpreted to be limited to visible light. The light rays may in particular comprise light rays in the visible spectrum, in the infrared spectrum and / or in the ultraviolet spectrum. The light source 11 may for example comprise a laser light source, wherein a generated laser beam is then expanded. To generate high power densities, the laser light source may in particular comprise a short-pulse laser, for example a femtosecond laser. While the optics 13 in 1 is represented as a single lens, this is merely symbolic to understand, and the optics 13 may include any suitable combination of lenses and / or other optical elements, around the planar wavefronts 14 to create.

Such arrangements for generating planar wavefronts are in themselves familiar to the expert and are therefore not explained in detail.

The device 10 of the 1 further includes a mask 15 , which in the illustrated example plane parallel to the planar wavefront 14 adjusted. In other embodiments, the illumination of the mask can also be done from one or more other angles than shown. The mask 15 may for example be an amplitude mask or a phase mask and generated from the plane wavefront 14 a pattern of high-energy areas 16 ie, a pattern of regions whose power density is above a predetermined threshold, which is suitable in particular for writing in a photosensitive material, wherein it is fundamentally not excluded that processes in the photosensitive material can also be triggered outside of the regions. The high energy areas 16 lie in particular in planes in a Talbot distance to the mask 15 or an integer fraction of the Talbot distance, for example, half a Talbot distance or one-quarter Talbot distance, or multiples thereof, ie, Talbot levels and / or fractional Talbot levels.

In 1 is still a photosensitive material 17 on a substrate 18 provided, which by means of a suitable recording 111 as by arrows 19 shown in three spatial directions is movable, for example by a three-axis actuators. Such a photosensitive material is also referred to as a photoresist or resist. By appropriate exposure, the photosensitive material 17 be changed so that, for example, in the case of a so-called positive resist exposed areas are dissolved out in a subsequent development step or in the case of a so-called negative varnish unexposed areas are dissolved out. By such an exposure, hereinafter also referred to as writing, for example, a polymerization of the photosensitive material can take place.

Such a movement as by arrows 19 symbolized by a controller 110 be controlled so that when moving the areas 16 which are within the photosensitive material 17 located corresponding structures in the photosensitive material 17 write, so that after appropriate development then three-dimensional structures can be formed. It should be noted that in other embodiments, a movement, for example, only in the xy plane, ie parallel to the mask 15 or the wavefronts 14 or in the form of otherwise limited movement relative to a full three-dimensional movement, if sufficient to produce desired structures. Before the exposure can be made an adjustment, which, for example, with respect to the actuator of the recording 111 can be done. In this case, a possibly present tilting of the photosensitive material is preferred 17 and / or the mask 15 aligned to an xy plane of the actuators, and the wavefront 14 then apply accordingly to the mask 15 and the photosensitive material 17 and thus also on the actuators of the recording 111 aligned.

It should be noted that in principle it is also possible, instead of or in addition to the movement of the photosensitive material 17 a movement of the areas 16 For example, by a movement of the light source 11 , the optics 12 and the mask 15 to perform. Is the extension of the wavefront 14 greater than the extent of the mask 15 , just the mask 15 to be moved.

In the embodiment of the 1 is a surface of the photosensitive material 17 also parallel to the wavefronts 14 adjusted, and depending on the nature and location of the desired structures, a different adjustment can be made.

In such a device 10 become, as it were, a multitude of areas 16 used simultaneously as "write heads" to move parallel through the movement of the photosensitive material 17 a structure in the photosensitive material 17 to write and thus ultimately (after developing) to create a three-dimensional structure. By controlling the movement of the photosensitive material, there is great flexibility in terms of the shape of the structures, while the large number of areas and the parallel writing associated therewith also makes it possible to process larger workpieces, ie larger volumes of photosensitive material, in an acceptable time.

Thus, with the device 10 efficiently writing three-dimensional structures.

In 2 a flowchart of a method according to an embodiment of the invention is shown schematically. The procedure of 2 in particular using the device 10 of the 1 however, it may be used independently.

In step 20 For example, a mask, such as an amplitude mask or a phase mask, is illuminated to generate a pattern of high-energy regions, ie, regions having an illumination intensity above a predetermined threshold. In step 21 For example, these high-energy regions (or some of the regions) are then moved in a photosensitive material, for example, two-dimensionally or three-dimensionally moved to write a structure in the photosensitive material. In step 22 For example, the photosensitive material is then developed, for example, by means of suitable chemicals to produce a three-dimensional structure. For example, when developing in step 21 exposed by the movement of the high-energy areas (in the case of positive coatings) or unexposed (in the case of negative coatings) parts of the photosensitive material, so as to obtain the desired three-dimensional structure.

In this exposure, as will be explained in more detail later, in particular two-photon effects can be exploited in order to achieve a higher contrast of the spatial energy distribution.

The following are with reference to the 3 to 7 some features of the embodiments of the 1 and 2 , in particular illuminating a mask for generating high-energy regions and moving the high-energy regions in the photosensitive material by way of examples, these examples being given by way of illustration only.

As already mentioned, amplitude masks or phase masks, for example, can be used as suitable masks for generating the high-energy regions. In this case, for example, line masks, also referred to as grids, can be used, which are mainly used for the following simulation examples, since the representation is clearer. However, masks are also possible which vary both in the x-direction and in the y-direction, the xy-plane as in 1 denotes the mask plane, while z denotes the direction perpendicular thereto. In 3 As an example of such a mask, a transfer function U of a sinusoidal amplitude mask with a period of 10 .mu.m is shown both in the x-direction and in the y-direction, which can serve, for example, for generating high-energy regions.

The generation of high-energy regions is then carried out according to the Talbot effect, according to which the intensity profile of the mask is imaged again at a predetermined distance, the Talbot distance. In so-called fractional Talbot planes, for example at half Talbot distance, quarter Talbot distance, third Talbot distance and the like, intensity maxima with a higher period result, these maxima also serving as high energy areas (spots).

For the production of solids, there are requirements that an intensity distribution in the planes used for writing must be very high and a distance to adjacent maxima along the propagation direction z should be so large that such secondary maxima are not in the photosensitive material, unless it is desired to write in multiple levels.

As an example, simulation results for a sinusoidal phase mask having a period of 10 μm and a wavelength of a light used for one-photon excitation of 450 nm will now be discussed. In addition, the following simulation examples generally assume an illumination intensity of 1 W / cm ² incident on the mask. In this case, with a suitable photosensitive material and suitable excitation wavelength, two-photon excitations can occur in which electrons of atoms of the photosensitive material absorb photons and the energy level of the electrons is thereby raised into a forbidden zone. In this energy state, the electrons dwell only a few Femtoseconds before the photon is emitted again. But if in this femtosecond time window another photon is absorbed by the excited electron, the electron is raised to a higher allowed state, and this absorbs twice the energy of a single photon, which corresponds to an increase in intensity. The excitation wavelength is preferably chosen such that the energy of a photon is half of the energy that is necessary for the excitation in the higher allowable state, and is for typical photosensitive materials, for example in the range of 300 nm-1000 nm If a one-photon excitation requires a wavelength of 450 nm, the corresponding wavelength for a two-photon excitation would be 900 nm. A sufficiently high probability for such a two-photon process is achieved by corresponding illumination intensities, which may be in the terawatt range, for example. Such illumination intensities can be achieved, for example, by short-pulse lasers, for example femtosecond lasers.

For the above example, single-photon absorption results in high-energy regions with a maximum illumination intensity of 5.2 W / cm ² and a half-width of 0.565 μm. In the case of two-photon absorption, the maximum intensity is 27.2 W ² / cm ⁴ with a half-width of 0.4 μm. It can thus be generated very small high energy areas with high intensities, which can then serve as write heads for writing in a suitable photosensitive material.

In the 4A and 4B is a spatial distribution of the intensity shown behind a sinusoidal phase mask with a period of 10 microns, a phase height of 7π and an exposure wavelength of 450 nm. z denotes the distance to the mask, the x-direction lies in the mask plane, corresponding to the coordinate system of 1 , For the black and white representation of the 4A A threshold of 2.6 W / cm ² corresponding to half maximum intensity was used, ie areas with an intensity above this threshold appear white, other areas appear black. The shows a sectional image at a distance of 332 microns from the mask (z = 332 microns in 4A ). There are clearly strong intensity peaks with a maximum intensity greater than 5 W / cm ² recognizable. These regions at a distance of 332 μm from the mask are the regions with the highest energy, with the illustrated intensity profile essentially repeating with the Talbot distance as the period. Thus, within the period in the x-direction (ie within the distance of the regions to each other), it is possible to arbitrarily write various patterns in the plane into the photosensitive material and also any patterns in the three-dimensional space up to the maximum thickness of the photosensitive material or to the next to write appropriate area.

If two-photon absorption is used to expose the photosensitive material, the contrast will increase. Figure ³ shows, by way of illustration, the square of the spatial intensity distribution, which is a measure of a probability of two-photon absorption, with a threshold of (13 W / cm ² ) ² corresponding to about half the maximum square intensity and shows the intensity distribution again at a distance of 332 microns, again with the same mask as in the 4A and 4B has been used. As can be seen, this results in a lower half-width and a smaller number of areas above the selected threshold than in a one-photon process, it being noted that in a two-photon absorption, the excitation wavelength of half the energy of the junction to be excited corresponds, so that in particular a suitable Photoresist is to be selected. A corresponding example will be discussed later.

In particular, arbitrary structures can be written with the masks discussed so far.

One application of such writes is the production of bulk gratings. Here, there is a requirement for a mask used that the distances of the high energy regions, i. the corresponding maxima of the intensity are uniformly spaced from each other and the patterns are the same in order to produce volume grids as homogeneous as possible. The following simulation assumes a phase mask as the exposure mask. In principle, both phase masks and amplitude masks can be used for such applications, with small periods of, for example, 3 .mu.m the forming maxima in amplitude masks tend to be higher than in phase masks, while in phase masks, the half-widths tend to be smaller and thus finer structures can be created.

In 4E and 4J For example, the spatial intensity distribution is shown behind a sinusoidal phase mask with a period of 3 μm for an illumination wavelength of 450 nm, where 4E similar to the 4A and 4C shows an intensity distribution in the x and z directions using a threshold, the threshold again corresponding to half the maximum intensity, in the present case 0.32 W / cm ² . The shows the intensity distribution at a distance of 48.6 μm to the mask.

As in particular in 4E As can be seen, there are major maxima (broader ranges) and various minor maxima, with both major maxima and minor maxima arranged in corresponding triangular patterns. Through such a mask nested grids of different web width can be generated.

If a two-photon absorption is used with a phase mask with a period of 3 microns, resulting in the 4G and 4H shown intensity distributions, wherein in 4G in turn, a representation in the xz plane with a threshold corresponding to half the maximum square intensity and 4H shows the intensity ² at a distance of 48.6 microns. In this case, only the main maxima of the 4E in 4G still above the threshold, which corresponds to a very high contrast. It is also possible here to write deeper structures in the photosensitive material.

In 4I is the representation of 4G shown again, here compared with the 4G the same scale was shown for the x-axis and the z-axis. However, the simulations were calculated for propagation in air. Propagation in the photosensitive material results in stretching along the z-direction, extending the high energy regions in the z-direction. Typical refractive indices of photosensitive material are, for example, in the range of 1.5.

In the examples of 4E - 4I Thus, with single-photon absorption for the simulated example, a maximum intensity of 0.64 W / cm ² results with a half-width of 0.57 μm, for a two-photon absorption a maximum intensity of 0.42 W ² / cm ⁴ with a half width of 0, 40 μm.

To refer to 4E to 4I To be able to compare the discussed phase masks for the production of volume gratings with a corresponding amplitude mask is in 4J an intensity profile for an amplitude mask with a period of 3 microns in the Talbot plane, ie at a distance of 20 microns shown. Since the intensity profile here has the same energy as an incoming wave, the maximum intensity here is higher than the intensity in the phase masks. However, for a one-photon absorption of 1 μm, the half-width is significantly higher than for the phase masks shown. The 4K shows the energy distribution with a scale according to the 4I , which for a threshold of 0.5 W / cm ² with the same scale as 4I was simulated for a two-photon absorption. As can be seen, this results in significantly larger high-energy areas, which are usable for writing, which reduces the flexibility in the production of complex three-dimensional structures.

In the 4A to 4K Thus, different intensity profiles are shown in which maximum intensities in the case of single-photon absorption are greater than 0.25 W / cm ² , in particular greater than 20.5 W / cm, whereby half-widths of the high-intensity regions are less than 5 μm, in particular less than 1 μm , are.

Although examples of one-photon absorption and two-photon absorption have been explained above, in other embodiments, multiphoton excitations with more than two photons may also be used, e.g. by appropriate choice of an excitation wavelength.

Now, referring to 4L to 4Q further illustrates the use of two-photon absorption to write structures in a photosensitive material. As explained above, two-photon absorption excites a transition which is twice the energy of a single photon of the exciting light. The probability of such a two-photon absorption depends on the square of the illumination intensity, as also already explained. For efficient use of the two-photon absorption, it is preferred to use an excitation wavelength at which the photosensitive material is at least largely transparent, so that, for example, as little light intensity as possible is lost by processes other than the desired two-photon absorption.

An example of a photosensitive material suitable for two-photon absorption is hereinafter used as an SU8-3000 photoresist. Here, with an excitation wavelength of 800 nm, a transition can be excited by means of a two-photon absorption (which then corresponds to an energy of a photon having a wavelength of 400 nm), this photoresist being approximately completely transparent at 800 nm.

As a mask for the following simulations, a phase mask with a period of 3 μm and a phase deviation of 7 π was used.

4L and 4M show the spatial distribution of intensity in air, the 4L a representation according to the 4A where z is the direction of proportion and x is a direction in the mask plane, and where areas shown in light are above one half maximum intensity, while dark areas are below half maximum intensity.

The 4M shows a section in a Talbot plane for z = 5.25 microns.

The 4N and 4O show representations according to the 4L respectively. 4M for a propagation within the photoresist SU8-3000, ie taking into account the refractive index of this medium. The refractive index n (λ) of the photosensitive material dependent on the wavelength λ was determined by the Cauchy equation n (λ) = A + B / λ ² + C / λ ⁴ where A = 1.5525; B = 0.00629 and C = 0.0004. In doing so, the position of the Talbot planes shifts through the medium, so that in this case 4O shows a section z = 8.55 microns.

The and 4Q finally show the spatial distribution of the square intensity in the photosensitive material, which corresponds to a measure of a probability of two-photon absorption. 4Q again shows a section for z = 8.55 μm, corresponding to the distance of the Talbot plane of the 4O , Since the photoresist SU8-3000 is practically transparent as explained for the illumination wavelength used of 800 nm, practically no single-photon absorption takes place. 4P thus shows the absorption probability of energy corresponding to a wavelength of 400 nm by two-photon absorption in the photosensitive material. As turn out 4Q As can be seen, a high contrast can be achieved in accordance with a small half width.

In 5 For example, various patterns generated by masks as discussed above are shown in a plane parallel to the mask (ie, in an xy plane). For example, square or rectangular patterns (a), triangular patterns (b) or honeycomb patterns (c) may be generated. These patterns are examples of regular tiling, and other regular tilings or other patterns can be created. Thus, it can be seen from the foregoing that by means of masks, in particular amplitude masks or phase masks, high-energy regions can be generated in different pattern arrangements, in particular in a Talbot plane or a Talbot fractional plane, which can then be used to write structures in photosensitive material ,

Now, with reference to the 6 and 7 Examples of writes are explained. First, referring to 6 describes a writing method in which a movement of the photosensitive material relative to the high-energy regions takes place only in a plane perpendicular to the propagation direction, ie in the xy plane, so that structures are written, for example, within Talbot planes. As an example of this shows 6 a writing of triangular structures in a Talbot plane. As shown in (a), quadratic high-energy regions are used. In a first step, the photosensitive material can then relative to the high-energy areas as by an arrow 60 can be moved, whereby strokes are written. Second, as shown in (c), another movement is made as indicated by an arrow 61 , and finally, at (d), a final movement is made according to an arrow 62 , thereby completing the triangular structures. In this case, therefore, a triangular structure is formed in the photosensitive material by only three movements.

Next, referring to 7 an example of a three-dimensional writing with relative movement of photosensitive material to high-energy areas in three spatial directions will be explained. In this case, starting from a triangular structure shown at (a), a tetragonal structure similar to a crystal structure is to be formed. As shown in (b), the high-energy regions shown are in a Talbot plane 70 and in half a Talbot level 71 arranged, this structure continues accordingly, so that in 7 only a section is shown.

At (c), a first movement corresponding to an arrow 72 performed, reducing the two levels 70 . 71 get connected. At (d), the next movement will be according to an arrow 73 performed, then at (e) another movement according to an arrow 74 , at (f) the next movement according to an arrow 75 and at (g) a fifth movement corresponding to an arrow 76 carried out. These movements can be performed without settling, the structure then still with a final movement corresponding to an arrow 77 is completed, what a "settling" takes place, for example, by briefly darkening the light source.

It is thus possible to write complex volume gratings which mimic a crystal structure, for example, with feature sizes in the micrometer range.

In the 6 and 7 Write operations shown are merely illustrative, and depending on the nature of the desired structures, essentially any arbitrary write operation can be performed.

By means of such writing processes, it is possible, for example, to produce beam shapers with novel properties, for example micro-optical components, sub-wavelength structures such as moth eyes or polarization filters for circularly polarized light. Also can layers for lenses or beamformer for Lichthomogenisierung be prepared.

As already apparent from the above discussion of modifications and variations, the scope of the present invention is not limited to the illustrated embodiment.

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited non-patent literature

• PNAS, Vol. 101, no. 34, p. 12,428 to 12,433; 2004, Seokwoo Jeon; Three-dimensional nanofabrication with rubber stamps and conformable photomasks; Advanced Materials, Vol. 16, no. 14, p. 1369-1373; 2004 [0004]
• Seokwoo Jeon; Fabrication of three dimensional nanostructures using two photon lithographs in a single exposure step; Optics Express, Vol. 14, no. 6, p. 2300-2308; 2006 [0004]
• Justyna K. Gansel; Gold helix Photonic Metamaterial as Broadband Circular Polarizer; Science, Vol. 325, p. 1513-1515; 2009 [0006]
• MS Rill; Photonic Metamaterial Structures by 3D Laser Writing; OSA / FiO / LS / META / OF &T; 2008 [0006]
• Alexandra Boltasseva; Fabrication of optical negative-index metamaterials: Recent advances and outlook; Metamaterials, Vol. 2, p.1-17; 2008 [0006]
• Yong-Lai Zhang; Designable 3D nanofabrication by femtosecond laser direct writing; Nanotoday, Vol. 5, p. 435-448; 2010 [0006]

Claims (15)

A method of fabricating three-dimensional structures, comprising: irradiating a mask ( 15 ) for generating a pattern of regions, wherein in the regions a power density is above a predetermined threshold, and moving at least a portion of the pattern of regions in a photosensitive material relative to the photosensitive material ( 17 ) to write a structure in the photosensitive material. Method according to claim 1, wherein the mask ( 15 ) comprises a phase mask or an amplitude mask. The method of claim 1 or 2, wherein said regions are in a Talbot plane or a Talbot fractional plane. The method of any of claims 1-3, wherein the relative moving comprises only moving in a plane parallel to a mask plane. The method of any of claims 1-3, wherein the relative moving comprises three-dimensional moving. Method according to one of claims 1-5, wherein a half-width of the regions is less than 5 microns, preferably less than 1 micron, is. The method of any one of claims 1-6, wherein a maximum power density in the regions is at least 0.1 x, preferably at least 0.5 x a power density of a wavefront incident on the mask. Method according to one of claims 1-7, wherein the regions in a plane parallel to a plane of the mask form a regular tiling, preferably a rectangular pattern, a triangular pattern or a honeycomb pattern. The method of any of claims 1-8, further comprising developing the photosensitive material ( 17 ). The method of any one of claims 1-9, wherein writing the structure comprises exciting a multiphoton process. The method of claim 10, wherein a photon energy of a radiation used for irradiation corresponds to half the excitation energy of the photosensitive material. The method of any one of claims 1-11, wherein moving the pattern relative to the photosensitive material comprises moving the mask ( 15 ) and / or moving the photosensitive material ( 17 ). A device for producing three-dimensional structures, comprising: a radiation source arrangement ( 11 . 12 ) for illuminating a mask ( 15 ) such that a pattern of areas ( 16 ) whose illumination intensity is above a predetermined threshold value, a recording ( 111 ) for receiving a photosensitive material ( 17 ), the recording ( 111 ) is movable in at least one direction parallel to a mask plane, and a control for moving the photograph such that through the regions ( 16 ) a structure in a on the recording ( 111 ) located photosensitive material ( 17 ) is writable. The device of claim 13, wherein the radiation source assembly comprises a short pulse laser. Apparatus according to claim 13 or 14, wherein the apparatus is designed for carrying out the method according to any one of claims 1-12.

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