Method for producing three-dimensional structures in lithographic materials by means of a laser lithography device - Patent Application 20070122997

Abstract

To provide a method for manufacturing a high-precision three-dimensional structure in lithographic materials by using a simple and rapid manner.SOLUTION: There is provided a method for manufacturing a three-dimensional target structure (42) in a lithographic material by using a laser lithographic apparatus. The method comprises the steps of: determining an exposure data set representing a local exposure amount for a scanning manifold as a function of position; defining and analyzing a structure that approximates the target structure based on the exposure data set; determining an analysis data set representing an analyzed structure; determining a deviation data set representing a deviation from the target structure; and defining a correction structure based on the correction exposure data set.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a three-dimensional target structure in a lithographic material by means of a laser lithography apparatus, and also to a laser lithography apparatus adapted for this method. [Background technology]

[0002] This type of technology is particularly used in the fabrication of micro- or nanostructures in areas where high precision and design freedom for the simultaneously fabricated structures are desired. In such laser lithography methods, structures are typically written by emitting an exposure dose of laser light to a lithographic material in the focal area of ​​the laser writing beam, thus locally defining the structure area, for example, by locally hardening or polymerizing the lithographic material. Then, by displacing the focal area within the lithographic material, the entire three-dimensional structure can be created.

[0003] A laser lithography method is known from DE 10 2017 110 241 A1, in which a surface of a desired structure is produced by locally varying the emitted exposure dose (exposure variation).

[0004] In order to be able to exploit these exposure variations and create structures with high precision, a link must be established between the exposure dose and the exposure result. A corresponding calibration process is usually required for this purpose. For this purpose, it is known to generate reference structures with a predefined exposure dose before actually writing the desired structure, then develop them, and subsequently measure their surface optically or mechanically. Depending on the measurement results, the exposure dose is then usually adjusted accordingly, and this process is repeated iteratively until the achieved result meets the predetermined requirements. However, such an optimization process is usually time-consuming and difficult to automate. Furthermore, such a calibration process usually has to be performed again at certain time intervals. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] DE 10 2017 110 241 A1 Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to produce high-precision three-dimensional structures in lithographic materials in a simple and rapid manner. [Means for solving the problem]

[0007] This object is achieved by a method according to claim 1. The method is a laser lithography method, in particular a so-called direct laser writing method, in a volume of lithographic material and / or in a volume filled with lithographic material by means of a laser lithography apparatus. According to this method, a target structure is written and / or defined in the lithographic material by successively defining a plurality of structure areas (hereinafter also referred to as "voxels") that are stacked one on top of the other to form the target structure (i.e. by "writing" the lithographic material with the laser lithography apparatus).

[0008] To write the structure area, and thus the target structure, the focal area of ​​the laser writing beam passes through the lithography material through a scanning manifold. In a simple case, the scanning manifold can be a scanning curve, but it can also be more complex. In other words, the focal area of ​​the laser writing beam is displaced through the lithography material. For this purpose, the laser writing beam can be controlled within the writing area of ​​the laser lithography device with the precision required for structuring purposes. As an example, the laser writing beam can be deflected in a controlled manner by a beam guide device. However, it is also conceivable that the lithography material or the substrate with the lithography material is displaced in a controlled manner relative to the laser writing beam by a positioning device. The two displacement concepts can also be used together.

[0009] An exposure dose is applied to the lithographic material in the focal region of the laser writing beam, and in particular, using multiphoton absorption, the lithographic material is locally modified, thus creating or writing structure areas. In this respect, the lithographic material is locally structured, in particular using multiphoton absorption. In particular, the lithographic material is chemically and / or physically modified, for example hardened or polymerized, by the exposure dose of the laser writing beam. The exposure dose is in particular a volumetric dose of radiant energy. The size of the modified structure areas ("voxels") in the lithographic material depends on the exposure dose. By varying the exposure dose, the spatial expansion of the structure areas or voxels, respectively, in particular the structure height, can be modified.

[0010] Applying the exposure dose via multiphoton absorption can be particularly advantageous in the type of 3D laser writing used in this case. For this purpose, the lithographic material is preferably designed in such a way that the laser writing beam is tuned to the lithographic material in such a way that changes in the lithographic material (e.g., local polymerization) are possible only through the absorption of multiple photons. For this purpose, for example, the wavelength of the laser writing beam can be selected so that the energy input required to modify the lithographic material can be achieved only through the simultaneous absorption of two or more quanta, and therefore the associated quantum energy can be of such magnitude. The probability of such a process does not depend linearly on intensity and is significantly increased in the focal region compared to the rest of the writing beam. Careful consideration has shown that the probability of absorption of two or more quanta is a function of the square or higher power of the radiation intensity. In contrast, the probability for linear absorption processes shows a different intensity dependence, especially at lower powers of radiation intensity. Because the penetration of the laser writing beam into the lithographic material is attenuated (e.g., according to Beer's law), writing deep below the liquid surface of the lithographic material in the focal region using a linear absorption process would be problematic because, due to attenuation, the focal point below the surface in the focal region does not necessarily provide the highest absorption probability. On the other hand, the multiphoton absorption mechanism allows for the local delivery of the desired exposure dose within the volume of the lithographic material, even relatively deep below the liquid surface, thereby modifying the lithographic material. Therefore, a device for gradually lowering a support structure into a bath of lithographic material, as known in the prior art, is not required.

[0011] To solve the problem, it is particularly proposed to first provide at least one exposure data set. This exposure data set represents a local exposure dose for a scanning manifold as a function of position (step a). In particular, the at least one exposure data set can represent a local exposure dose for each scanning point along a scanning curve of a laser writing beam through the lithographic material. In this regard, the at least one exposure data set specifies the exposure dose to be used at a specific position of the scanning manifold. The at least one exposure data set is particularly stored or can be stored in a memory of a control device of the laser lithography apparatus. The at least one exposure data set can be provided in particular by providing a structure data set (e.g., CAD data) representing a target structure to be generated and / or storing this in the control device, which can then be used to determine the at least one exposure data set computer-aided, for example, by a control device of the laser lithography apparatus configured for this purpose.

[0012] In a further step, structures approximating the target structure are then defined or generated in the lithographic material based on the at least one exposure data set (step b). For this purpose, in particular, a laser lithography apparatus is controlled according to the at least one exposure data set, so that structure areas are sequentially written into the lithographic material according to the exposure dose specified by the at least one exposure data set.

[0013] Next, already Definition At least one part of the structure is analyzed using an imaging measurement method with spatial resolution (step c). The structure is only analyzed after the writing process is completed. analysis It can also be thought of as a structure being analyzed. Definition It is conceivable that the data will be analyzed during the analysis (i.e., "online"). DefinitionThe topography or shape of the structure is measured. In particular, the images can be captured using optical measurement devices, for example based on OCT (Optical Coherence Tomography). Definition The complete structure is analysis However, if you have already Definition Only sub-regions of the structure being written, e.g. regions that require special optimization (e.g. transition regions resulting from the juxtaposition of sub-structures resulting from separated writing regions, see below) analysis It is also possible to do this.

[0014] Structure analysis In or analysis Later, analysis At least one element representing the structure, especially its shape or topography analysis The data set is determined by a computer.

[0015] Then, the target structure is Definition A deviation data set representative of deviations, in particular topography or shape, of the generated structure is determined by the computer (step d). The deviation data set is determined in particular by comparing the at least one analysis data set with a structure data set representative of the target structure to be generated. This structure data set can in particular be at least one exposure data set. The deviations are determined in particular by comparing the target topography of the target structure with the at least one exposure data set. Definition This is understood to mean the difference between the actual topography of the structure to be constructed and the actual topography of the structure to be constructed.

[0016] In a further step (step e), at least one corrected exposure data set is determined by the computer based on the deviation data set, in particular representing a corrected exposure dose required to compensate for the deviation, as a function of position relative to the scanning manifold.

[0017] A correction structure is then generated based on the at least one corrected exposure data set (step f).

[0018] Based on the corrected exposure data set, a separate structure is generated, in particular based on the exposure data set Definition It is conceivable that the at least one correction exposure data set may be spatially separated from the structures written based on the at least one exposure data set. The at least one correction exposure data set may then specify an exposure dose as a function of position, particularly for the scan manifold, where the exposure dose is determined such that structures written based on the correction exposure data set deviate less from the target structures than structures previously written based on the exposure data set from the target structures. It is also possible to use the correction structures for post-correction of structures originally written based on the at least one exposure data set. The at least one correction exposure data set may then specify an exposure dose as a function of position, particularly for the scan manifold, where the exposure dose is determined such that structures written based on the correction exposure data set deviate less from the target structures than structures previously written based on the exposure data set from the target structures. Definition The correction structure is determined so that the deviation between the written structure and the target structure is reduced. For example, the correction structure can be applied to the already written structure.

[0019] Such a method allows for the characterization of structures already written in situ and for the direct correction of deviations from the desired target structure, resulting in the creation of structures with high precision at a relatively low time and equipment cost. In particular, this method: analysis This allows for the direct detection of deviations from the desired target structure on an already manufactured structure without the need to prepare the structure in advance.

[0020] In particular, no development of the lithographic material occurs between the structure definition step (step b) and the structure analysis step (step c). Therefore, in particular, no unexposed lithographic material is removed, nor are any structures already fabricated based on the hardened exposure data set. This method allows for in-situ optimization of the written structure, which allows for faster cycle times. In particular, this method allows for the automation of structure optimization, since complex development steps are no longer necessary.

[0021] The exposure dose (exposure variation) can be corrected by laser modulation, for example by an acousto-optical modulator known from the prior art, or by an autopolarizer. The exposure can also be varied using other beam shaping methods that can adjust the amplitude, phase or polarization of the laser writing beam.

[0022] In the present context, lithographic materials are generally used to refer to substances whose chemical and / or physical material properties can be modified by irradiation with a writing laser beam, for example in a so-called lithographic coater. Depending on the type of modification induced by the writing beam, lithographic materials can be divided into so-called negative resists (irradiation causes local hardening or a decrease in solubility in the developer medium) and so-called positive resists (irradiation causes a local increase in solubility in the developer medium).

[0023] According to an advantageous development, steps c) to f) of the method described above comprise a step of analyzing the structure and determining at least one analysis data set (step c), a step of determining a deviation data set (step d), a step of determining at least one correction exposure data set (step e), and a step of determining the correction structure. Definition Step f) is actually Definition The process is repeated iteratively, so that the deviation of the resulting structure from the desired target structure is increasingly reduced, i.e., within each iteration, after the correction structure is written, the resulting structure is again analysis Steps c) to f) are preferably repeated iteratively until the determined deviation falls below a predefined or predefinable threshold value, in particular a threshold value that is present or can be stored in the control device.

[0024] DefinitionThe imaging measurement method used to analyze the structure can be, in particular, optical microscopy, more particularly nonlinear microscopy. For example, it is conceivable that the structure to be analyzed is first irradiated with excitation light, and the reflected radiation backscattered, reflected, or transmitted by the structure to be analyzed is detected by an optical measurement device. The measurement device can in particular comprise measurement optics, which are preferably formed confocal with a device (e.g., a beam guide device) that generates the laser writing beam. It is also particularly advantageous if the laser writing beam passes through a lens in the lithographic material to define the structure, and if this lens is also used to collect the radiation emitted by the structure to be analyzed. However, in principle, it is also possible to use a separate measurement device, in particular a separate lens, for the microscope.

[0025] In particular, the structure was analysis In this respect, in particular, the fluorescent signal generated by the lithographic material when it is irradiated with excitation light is evaluated. Depending on whether the lithographic material is in an unmodified initial state (e.g., non-polymerized state) or in a state modified by the laser writing beam (e.g., polymerized state), different fluorescent signals are generated, and as a result, structural contrasts can be detected.

[0026] In a particularly advantageous embodiment of the method, DefinitionFor the purpose of analyzing the structure, the same can be optically scanned with a laser writing beam for imaging, and radiation backscattered, reflected, transmitted, or generated by fluorescence is detected by a measurement device. In this regard, the laser writing beam is used to illuminate the structure being analyzed with excitation light. This scanning with the laser writing beam itself has the advantage that no additional imaging device is required. Furthermore, since no optical transformation is required, the analysis can be performed particularly quickly in this manner. To scan the structure, the exposure dose is preferably selected to be sufficiently low so that no structures are defined in the lithographic material during scanning. In particular, a laser intensity is selected that is below the threshold at which noticeable polymerization of the lithographic material occurs (polymerization threshold). It is also possible to illuminate the structure to be inspected with laser light of various laser wavelengths, which have such low linear or nonlinear absorption in the lithographic material that no structures are defined in the lithographic material during scanning.

[0027] Additionally or alternatively, Definition The resulting structure can also be analyzed by mechanically scanning it, for example with a needle-shaped scanning tip, as in an atomic force microscope, which is particularly advantageous for lithographic materials that are initially liquid.

[0028] According to an advantageous development, the target structure is formed by sequentially forming a plurality of substructures. Definition By doing DefinitionThe target structure can be approximated accordingly. Such an arrangement is particularly advantageous when the target structure to be generated is larger than the maximum writing area of ​​the laser lithography device. To generate the substructures, the target structure is preferably rasterized by a computer, in particular decomposed into structure areas (voxels), each of the substructures being preferably formed by a set of contiguous structure areas (voxels). To generate the substructures, further sub-exposure data sets are then determined by the computer from the at least one exposure data set or the at least one corrected exposure data set, which data set represents a local exposure dose for the scanning manifold for each substructure. After each substructure has been defined, the writing area of ​​the laser lithography device is displaced, in particular, by positioning means known from the prior art, for example.

[0029] In principle, the substructures may have different shapes. If the target structure to be generated has a height extension greater than the maximum writing height of the laser lithography device, it may be particularly advantageous if the target structure is at least partially divided into substructures stacked one on top of the other in a layer. In this regard, at least a subset of the substructures is designed so that the target structure is approximated by multiple substructures stacked one on top of the other in a layer, i.e., multiple substructures one on top of the other in the height direction. After writing each substructure, the lithography material and / or the substrate carrying the lithography material is then moved downwards in a controlled manner, in particular by a positioning device.

[0030] According to an advantageous development, the at least one exposure data set and the at least one corrected exposure data set may each comprise a different grayscale image data set, where different gray values ​​represent different exposure doses. In particular, the at least one exposure data set and the at least one corrected exposure data set each consist of a grayscale image data set. In this respect, the data sets can be visualized as grayscale images. In particular, the laser lithography apparatus is controlled as a function of the grayscale image data set. The at least one exposure data set is preferably provided by loading a grayscale image file into a control device of the laser lithography apparatus and storing it in a memory.

[0031] As described above, if the target structure is composed of substructures stacked on top of each other within a layer, and at least one exposure data set and at least one correction exposure data set are designed as grayscale image data sets, then the grayscale image data sets of the at least one exposure data set and / or the grayscale image data sets of the at least one correction exposure data set are divided into multiple partial grayscale image data sets. The partial grayscale image data sets then together represent an image stack along the stacking direction of the substructures. The highest gray value of each grayscale image then corresponds to the exposure dose leading to the maximum structure height that can be written with the laser lithography device in one plane (i.e., without the need to move the lithography material in the height direction relative to the focal area of ​​the laser writing beam).

[0032] According to an advantageous refinement, the at least one analysis data set can also comprise at least one grayscale image data set, in particular having different gray values ​​representing different structure heights of the analyzed structure. The deviation data set, in particular the correction exposure data set, can then also be determined by comparing the at least one analysis data set with the at least one exposure data set.

[0033] The initially stated object is also achieved by a laser lithography apparatus according to claim 12. The laser lithography apparatus is designed to produce three-dimensional target structures in a lithography material. The laser lithography apparatus comprises a laser source for emitting a laser writing beam. Furthermore, the laser lithography apparatus comprises a beam guiding device, in particular comprising optical means such as lenses, mirrors, etc., for defining a beam path for the laser writing beam from the laser source to the lithography material. Furthermore, focusing optics are provided, which are designed to focus the laser writing beam in a focal region. Also, a scanning device is provided for displacing the focal region of the laser writing beam relative to the lithography material. The scanning device can be a deflection device (e.g., including a deflection mirror) for modifying the position of the focal region of the laser writing beam in the lithography material. Additionally or alternatively, the scanning device can also comprise a positioning device, by means of which the lithography material or a substrate carrying the lithography material can be displaced relative to the laser writing beam.

[0034] The laser lithography apparatus also processes structures defined or written in the lithography material by the laser writing beam. analysis The measuring device may comprise an imaging measuring device for measuring the fluorescence intensity of the structure being analyzed. In particular, the measuring device may comprise a detecting device for detecting radiation backscattered, reflected, transmitted or generated by fluorescence from the structure being analyzed. Additionally or alternatively, the measuring device may comprise a probe with a scanning tip, whereby the structure can be mechanically scanned.

[0035] The laser lithography apparatus also comprises a control device configured to carry out the above-mentioned method, the control device including in particular a calculation unit and a non-volatile memory in which the above-described datasets are or can be stored. [Brief explanation of the drawings]

[0036] The invention will now be explained in more detail with the aid of the drawings. [Figure 1] FIG. 1 is a simplified schematic diagram of a laser lithography apparatus. [Figure 2a] FIG. 2a is a sketch illustrating the sub-steps of the method for generating a three-dimensional structure. [Figure 2b] FIG. 2b is a sketch illustrating the sub-steps of the method for generating the three-dimensional structure. [Figure 3] FIG. 3 is a schematic flowchart of one embodiment of a method for generating a three-dimensional structure. [Figure 4] FIG. 4 is a schematic diagram illustrating the division of an exposure data set into sub-exposure data sets. [Figure 5] FIG. 5 is a schematic diagram illustrating the division of an exposure data set into sub-exposure data sets. DETAILED DESCRIPTION OF THE INVENTION

[0037] In the following description and drawings, the same reference numbers are used for the same or corresponding features.

[0038] 1 is a schematic diagram of a laser lithography apparatus, generally designated by the reference numeral 10. The laser lithography apparatus 10 comprises a laser source 12 for emitting a laser writing beam 14. The laser lithography apparatus 10 also comprises a beam guiding device 16 that defines a beam path 18 for the laser writing beam 14 from the laser source 12 to a lithographic material 20 to be structured, which is shown as an example bath of liquid material.

[0039] In the illustrated example, the beam guiding device 16 includes multiple modules that perform optical and / or mechanical functions. For example, the beam path 18 may first pass through a modulation module 22 to shape the appropriate beam pulses. The laser lithography apparatus 10 also includes focusing optics 24 for focusing the laser writing beam 14 to a focal region 26 (see also FIG. 2a) of the laser writing beam 14. The focusing optics 24 includes, for example, a lens module 28 through which the laser writing beam 14 is directed onto the lithography material 20.

[0040] In the illustrated example, the laser lithography apparatus 10 also comprises a scanning device 30, by means of which the focal region 26 of the laser writing beam 14 can be displaced within a writing region 32 with the precision required for structuring the lithography material 20. In the illustrated example, the scanning device 30 includes a beam steering module 34, which may have, for example, a galvanometer scanner unit for controlled deflection of the laser writing beam 14. In embodiments not shown, the scanning device 30 may also comprise a positioning device that serves to precisely move the lithography material 20 or the substrate 36 together with the lithography material 20 relative to the focal region 26 of the laser writing beam 14. The figure also shows a coordinate system with mutually orthogonal axes x, y, and z, where the x-axis and y-axis define a writing plane and the z-axis corresponds to the vertical direction.

[0041] The laser lithography apparatus 10 also includes a controller (not shown) that includes a computing unit and a non-volatile memory.

[0042] To generate three-dimensional structures in the lithographic material, the focal region 26 of the laser writing beam 14 is displaced relative to the lithographic material 20 by a scanning device 30, so that the focal region 26 advances through the lithographic material 20 via a scanning manifold (indicated by arrow 38 in FIG. 1). At the focal region 26 of the laser writing beam 14, an exposure dose is locally applied to the lithographic material 20, particularly utilizing multiphoton absorption, resulting in the local definition of a structure region 40 (see FIG. 2b). For example, the lithographic material 20 is locally polymerized and thus structured.

[0043] An advantageous embodiment of a method for producing a three-dimensional structure by means of a laser lithography apparatus, in particular by means of the above-mentioned laser lithography apparatus 10, will now be described with reference to FIGS. 2a to 5. FIG.

[0044] FIG. 2a shows, in a cross-sectional view, an example of a target structure to be written into a volume of lithographic material 20 by 3D laser lithography. Target structure 42 is designated by reference numeral 42 in FIG. 2a and has an outer surface 44, which is shown in FIG. 2a by a dashed line. In the example shown, target structure 42 has a pronounced height profile 46, which is used to illustrate the effect of varying exposure dose. However, of course, other geometric shapes are also contemplated. For example, outer surface 44 of target structure 42 may have a profile with a different slope or curve.

[0045] For the lithographic production of the target structure 42, an exposure data set is first provided, which represents the local exposure dose for the scanning manifold 38 as a function of position (step 100 in FIG. 3). The exposure data set can in particular be a grayscale image data set representing the target structure 42. For example, a grayscale image file can be loaded into the control device of the laser lithography apparatus 10. It is also possible that a structural data set representing the target structure 42 is first provided (e.g., CAD data), and then the exposure data set is determined by a computer from this structural data set.

[0046] In the next step (step 102 in FIG. 3), the laser lithography apparatus 10 is then controlled according to the exposure data set, resulting in the creation of a structure 48 that at least approximates the target structure 42 (the outer surface of which is depicted by a continuous line in FIG. 2b and designated by reference numeral 50). As shown by way of example in FIG. 2a, the structure 48 may be generated by, for example, the focal region 26 moving through the scanning manifold 38, and in the process, by emitting a sequence of laser pulses at a predetermined pulse rate and pulse length. Definition This allows for a series of structure regions 52 (voxels) along the scan manifold 38 that form the structure 48. Definition The structure regions 52 are similar in shape to one another or are identical in shape. The size of the write structure regions 52, and therefore the height of the structure, is related to the absorbed exposure dose.

[0047] Due to different effects (e.g., locally different responses of the lithography material to the laser input, optical system errors, tilt of the substrate 36, etc.), the structures 48 generated based on the exposure data set usually do not exactly correspond to the desired target structures 42. Therefore, according to the method, in a further step (step 104 of FIG. 3), Definition The resulting structure 48 was analyzed, and in particular: Definition The topography or shape of the structure 48 is measured in situ, i.e., in particular, by measuring the topography or shape of the lithographic material 20 or Definition This is done without first developing the resulting structure 48. Definition The resulting structure 48 is examined using a confocal fluorescence microscope, where the already DefinitionThe resulting structure 48 is first optically scanned with the laser writing beam 14, and then the fluorescent signal emitted by the sample is analyzed. For this purpose, the laser lithography apparatus 10 can then have a corresponding measuring device 54 (see FIG. 1), for example a fluorescent detector. By way of example, preferably, the beam path of the radiation emitted by the sample runs along the beam path of the laser writing beam.

[0048] The structure 48 can also be mechanically scanned by a scanning tip (not shown) to analyze it, in which case the laser lithography apparatus 10 may include a scanner (not shown).

[0049] Structure 48 analysis During and / or analysis After, next, Definition The structure 48, especially its topography or shape. analysis A data set is determined. By way of example and preferably, the analysis data set is also a greyscale image data set, with different grey values ​​representing different structure heights (z-direction).

[0050] In a further step (step 106 in FIG. 3), an exposure data set representing the target structure 42 and the data already present in the target structure 42 are now Definition A deviation dataset is determined by comparing the exposure dataset with an analysis dataset representing deviations of the exposed structures 48 (see FIG. 2b). In particular, the deviation dataset can be determined by the difference between the grayscale image dataset of the exposure dataset and the analysis dataset.

[0051] A check is then made to determine whether the determined deviation is below a predetermined threshold (step 108 in FIG. 3). DefinitionIt is checked whether the scanned structure 48 already sufficiently corresponds to the desired target structure 42. In this case, the method ends (step 110 of FIG. 3). However, if the deviation exceeds a threshold, in a further step, a corrected exposure data set is determined based on the deviation data set (step 112 of FIG. 3) representing the corrected exposure dose for each scan point of the scan manifold 38 in order to compensate for or at least reduce the deviation from the target structure 42.

[0052] In a further step, the laser lithography apparatus 10 is then controlled based on the corrected exposure data set (step 114 of FIG. 3) so that the corrected structure Definition Based on the corrected exposure data set, Definition "New" structures, spatially separated from the previously written structures, can be generated, in particular at different locations on the substrate 36. It is also possible to use correction structures solely for post-correction of previously written structures based on at least one exposure data set. In this case, in particular, the focal region 26 of the laser writing beam 14 can again move the previously laterally moved scanning manifold 38, with an appropriately adapted exposure dose as a function of position being used according to the correction exposure data set.

[0053] Steps 104-114 are repeated iteratively until the determined deviation of the actually produced structures 48 from the desired target structures 42 falls below a threshold value.

[0054] If the desired target structure 42 is larger than the maximum write area of ​​the laser lithography apparatus 10, the target structure 42 can be computationally decomposed into substructures that together approximate the target structure 42. To generate the substructures, further subexposure data sets are then determined by the computer from at least one exposure data set that represents, inter alia, the local exposure dose for the scanning manifold 38 for each substructure. The substructures are then written sequentially, and the resulting structures are then reconstructed according to the method described above. analysisand optimize it. In this case, analysis The data set, deviation data set and / or correction exposure data set are optionally decomposed into partial data sets according to the partial structure.

[0055] Figure 4 shows an example where the target structures have a larger extension in the scan plane (xy plane) than the writing area 32 of the laser lithography apparatus 10. A grayscale image 56 representing an exposure data set is shown by way of example in Figure 4. As shown by way of example in Figure 4, the grayscale image 56 or the exposure data set can be decomposed into partial grayscale images 56a-d and / or partial grayscale image data sets on the basis of which partial structures are then written.

[0056] If the extension of the target structure 42 in the height direction (z-direction) is greater than the maximum writing height of the laser lithography apparatus 10 per scan plane, the target structure 42 can be decomposed into substructures stacked on top of each other, for example in layers. This case is depicted in sketch form in Figure 5. Definition To achieve this, the exposure data set (depicted in FIG. 5 by grayscale image 58) can then be decomposed into multiple sub-exposure data sets (depicted in FIG. 5 by a stack of corresponding grayscale images 58a-h). Grayscale images 58 and 58a-h are shown in FIG. 5 only in sketch form to illustrate the image stack. Notably, however, each grayscale image 58 or 58a-h in FIG. 5 corresponds to an image in the manner of grayscale image 56 shown in FIG. 4. [Explanation of symbols]

[0057] 10 laser lithography apparatus 12 laser source 14 laser writing beam 16 beam guiding device 18 beam path 20 lithography material 22 modulation module 24 focusing optics 26 focal region 28 lens module 30 scanning device 32 writing region 34 beam directing module 36 substrate 38 scanning manifold 40 structure region 42 target structure 44 outer surface 46 profile 48 structure 52 structure region 54 measurement device 56 grayscale image 56a partial grayscale image 58 grayscale image 58a grayscale image

Claims

1. A method for generating a three-dimensional target structure (42) in a lithographic material (20) by a laser lithography apparatus (10), comprising: in a writing region (32) of the laser lithography apparatus (10), a focal region (26) of a laser writing beam (14) advances through the lithographic material (20) through a scanning curve (38), and an exposure dose is projected into the lithographic material (20) at the focal region (26) of the laser writing beam (14) to locally define a structure region (52) thereby defining the three-dimensional target structure (42), the method comprising the steps of: a) providing at least one exposure data set representing local exposure dose for a scan curve (38) as a function of position; b) defining a structure (48) that is a physical entity that approximates the target structure (42) represented by the at least one exposure data set; c) analyzing said previously defined structure (48) by spatially resolved imaging measurements to determine at least one analysis data set representative of the analyzed structure (48); d) determining a deviation data set representing deviations of the previously defined structures (48) from the target structure (42); e) determining at least one corrected exposure data set representing the corrected exposure dose as a function of position required to compensate for deviations relative to the scan curve (38); f) defining a correction structure based on the at least one corrected exposure data set.

2. 2. The method of claim 1, wherein development of the lithographic material (20) does not occur between the steps of defining the structure (48) (step b) and analyzing the structure (48) (step c).

3. 3. The method according to claim 1 or 2, wherein steps c) to f) are repeated iteratively such that deviations of the already defined structures (48) from the target structures (42) are gradually reduced until they fall below a predefined or predefinable threshold value.

4. A method according to claim 1 or 2, wherein the defined structure (48) is analyzed by optical microscopy.

5. 5. The method of claim 4, wherein to analyze an already defined structure (48), the structure (48) is scanned with a laser writing beam (14) and backscattered, reflected, transmitted or fluorescently generated radiation is detected for imaging by a measurement device (54), and the exposure dose for the scan is selected to be so low that no structure is defined in the lithographic material (20).

6. 3. The method of claim 1, wherein a previously defined structure (48) is mechanically scanned with a scanning tip to analyze said structure (48).

7. 3. The method of claim 1, wherein the target structure (42) is defined by a plurality of successively defined substructures that approximate the target structure (42) to one another, and a subexposure data set is determined by a computer for defining the substructures from the at least one exposure data set and / or the at least one corrected exposure data set, the subexposure data set representing a local exposure dose along a scanning curve for each substructure.

8. The method of claim 7 , wherein the substructures are layered on top of each other.

9. 2. The method of claim 1, wherein the at least one exposure data set and the at least one corrected exposure data set each comprise at least one grayscale image data set, different gray values ​​representing different exposure doses.

10. 10. The method of claim 9, wherein, to determine a partial exposure data set defining a substructure, the at least one grayscale image data set of the at least one exposure data set and / or the at least one corrected exposure data set is divided into a plurality of partial grayscale image data sets that together form an image stack (58a-h) along a stacking direction of the substructure.

11. 11. The method of claim 9 or 10, wherein the at least one analysis dataset also includes at least one grayscale image dataset, different gray values ​​representing different structure heights, and the deviation dataset is determined by comparing the at least one analysis dataset with the at least one exposure dataset.

12. 10. A laser lithography apparatus (10) for producing a three-dimensional target structure (42) in a lithography material (20), comprising: a laser source (12) emitting a laser writing beam (14); a beam guiding device (16) for defining a beam path (18) of the laser writing beam (14) from the laser source (12) to the lithography material (20); focusing optics (24) for focusing the laser writing beam (14) in a focal region (26); a scanning device (30) for displacing the focal region (26) of the laser writing beam (14) relative to the lithography material (20); an imaging measurement device (54) for analyzing the already defined structure (48); and a control device configured to perform the method of claim 1 or 2.

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