Apparatus and method for imprinting micro- and / or nano-structures

Abstract

The invention relates to a device (1) for embossing a structure into an embossing material, the device having a structure stamp (4, 4', 4'', 4''', 4iv, 4v, 4vi, 4vii, 4viii) for embossing the structure into the embossing material, characterized in that the structure stamp (4, 4', 4'', 4''', 4iv, 4v, 4vi, 4vii, 4viii) can be kept under constant local strain during embossing and separation from the embossing material.

Description

Technical Field

[0001] The present invention relates to an apparatus and a method for imprinting microstructures and / or nanostructures. Background Art

[0002] In the prior art, microstructures and / or nanostructures are produced by photolithography and / or with the aid of imprint lithography. Imprint lithography is understood to be a method in which micro- and / or nano-sized structures are impressed into a material using a stamp. This material is the stamp material applied to a substrate. In recent years, this imprint method has become increasingly important because it can be performed faster, more efficiently, and more cost-effectively than many photolithographic methods. Furthermore, it has been shown that the resolution achievable with imprint lithography is in no way inferior to that achievable with photolithography. In some cases, such as in so-called "first printing," better resolution can be achieved with imprint lithography than with conventional photolithography.

[0003] Most known embodiments of the device are either integrated into a so-called mask aligner or constructed as a stand-alone device, but these devices cannot process substrates larger than 300 mm. Aligners are particularly suitable for special imprinting equipment, as they are already widely used in the semiconductor industry for photolithography. Therefore, it is advantageous for suppliers to offer extensions and accessories that can complement or enhance the known mask aligner technology. A major advantage of the mask aligner is that, in most cases, the mask aligner already provides an optical system, in particular a lampshade, which serves to particularly fully illuminate the substrate and thus the stamp material being imprinted.

[0004] In addition to modified or extended mask aligners, there are also dedicated imprinting systems that are designed based on or for specific applications. These systems are mostly alignment devices that align the stamp and substrate with high precision. Furthermore, these systems may include vacuum generation options, special dosing equipment, and so on. Such imprinting systems are only rarely capable of imprinting stamp material onto substrates larger than 300 mm.

[0005] There are embossing devices which enable the production of structures for display devices, ie displays, in particular curved or flat screens.

[0006] There are five known imprint lithography techniques:

[0007] Microcontact printing and / or nanocontact printing (μ / nCP)

[0008] Replication Molding (REM)

[0009] Microtransfer molding (μTM) or nanoimprint lithography (NIL),

[0010] Micromolding in capillaries (MIMIC),

[0011] Solvent-assisted micromolding (SAMIM).

[0012] As is known, imprint stamps can be divided into two main families: either hard stamps (made of metal, ceramic materials or bulk glass or plastic) or so-called soft stamps (made of polymers, silicone etc.) can be used.

[0013] The elastomeric stamp is produced as a negative mold of the master. The master is a hard stamp made of metal, glass, quartz glass, plastic or ceramic, which is produced once using a correspondingly complex process. Any number of elastomeric stamps can then be produced from the master. The elastomeric stamp enables conformal, uniform contact over large surfaces. The elastomeric stamp must be separated from its master and the stamped product. This is due to the low surface energy of the elastomeric stamp, which is achieved by functionalization, in particular coating. Elastomer stamps are easier to separate from the substrate than hard stamps.

[0014] To automate the soft lithography process, the elastomeric stamp needs to be supported by a carrier. Currently, glass carrier substrates of varying thicknesses are used. However, the use of thick glass substrates at least partially reduces the flexibility of the elastomeric stamp. On the one hand, the glass carrier must be sufficiently thin to provide the necessary stability for the elastomeric stamp, while on the other hand, being sufficiently flexible to achieve the necessary flexibility.

[0015] Other embodiments of elastomeric stamps are produced as layer systems composed of elastomers or polymers: the mechanical properties, such as stability, elasticity, flatness, roughness, etc., can be significantly influenced by the carrier elastomer. The structure of the stamp is produced from the stamp material, in particular by molding a master.

[0016] The master can be manufactured in particular in a step-and-repeat process (S&R process). This is advantageous in particular when very large masters have to be manufactured. The master is manufactured by means of another master-master. However, in technical terms, the master for molding soft stamps is usually called a sub-master and the master for manufacturing a sub-master is called a master. So the definitions may differ. It has been disclosed that a master (or sub-master) of particularly large areas for molding soft stamps can be manufactured by a repeated embossing process (step-and-repeat process), which is characterized in that embossing is carried out at a first location, then the master-master (or master) is moved and thereafter embossed at least once more.

[0017] It is also conceivable to use a master plate in a step-and-repeat process to directly emboss the elastomeric die. This is particularly advantageous when the elastomeric die is very large. Here, the master plate is moved to a first position, where the elastomeric die is embossed, and then moved to a second position, different from the first, and embossed again. This process can be repeated as often as desired to produce an elastomeric die of any size. In particular, individual embossing locations of the elastomeric die can be embossed seamlessly.

[0018] Automatic separation of stamp and substrate after the imprint process is often difficult using a rigid carrier, whereby process automation and industrial usability of imprint lithography become only more difficult.

[0019] Another common problem with stamps is that they often have only a limited size. This makes it difficult to imprint large areas. One possible solution for continuous imprinting is roller stamping, but this will not be discussed further here. For imprinting micro- and / or nano-sized structures on large substrates, especially plates, the prior art has very few, and in particular no, mature, devices or methods.

[0020] Another problem is the detachment of the stamp from the surface. The detachment of the stamp must be precisely controlled so that the structure being impressed and the stamp are not damaged when the stamp is removed.

[0021] Another problem, especially with stamps used for large substrates, is that the distance required for imprinting or separating the substrate from the stamp must be at least twice the characteristic length of the substrate. Consequently, such devices consume extremely expensive cleanroom space. In other words, the problem with stamp detachment is that if the detachment is based on a linear lifting motion, the space required to separate the stamp from the imprinting surface is proportional to the length or diameter of the stamp. In other words, this method involves peeling the flexible stamp from the substrate with high shear forces.

[0022] Therefore, the separation mechanism of a stamping device for a linear lifting motion requires an experimentally determined distance, determined by the length of the stamp, its elasticity, and its adhesive properties. This distance must be covered by one side of the stamp to separate it from the substrate. This distance can be described using a modified tangent rod. Since the length of the tangent rod is variable, the length of the tensioned stamp varies. Without additional compensation, this change in stamp length alters the material stresses, which also means changes in the dimensional stability of the stamp.

[0023] An alternative embodiment of the separation mechanism uses a deflection roller to achieve a more efficient separation design. The die's orientation is changed at the deflection roller, which reduces the space required for the device compared to an embodiment without a deflection roller. However, when the die changes orientation, the forces acting on it and, therefore, the individual components of the stress tensor in the die change, thus compromising constant dimensional stability of the die.

[0024] Neither in the case of a separating mechanism with tangential rods nor in the case of a separating mechanism with deflecting rollers can a constant dimensional stability of the stamp be ensured, although this is a fundamentally important aspect of all embossing processes during the entire embossing process.

[0025] The existing technologies for the micro- and / or nanostructuring of surfaces primarily consist of photolithography and various imprinting techniques. Imprinting techniques work either with hard or soft stamps. Recently, imprint lithography in particular has taken over and is replacing classical photolithography. In imprint lithography, the use of so-called soft stamps in particular is becoming increasingly popular. The reasons for this are the ease of manufacturing the stamps, the efficiency of the imprinting process, the very good surface properties of the corresponding stamp materials, the low costs, the reproducibility of the imprinted products and, most importantly, the possibility of elastic deformation of the stamp during imprinting and demoulding. In soft lithography, stamps consisting of elastomers with a micro- or nanostructured surface are used for the production of structures in the range from 10 nm to over 1000 μm.

[0026] While imprint lithography using a stamp has its advantages, this technique also has disadvantages caused by the stamp's elasticity, which prevents it from always ensuring dimensional stability. This leads to inaccuracies and distortions in the depicted imprinted structure compared to the imprinted structure of the stamp. This material-related disadvantage is also at least reduced by the present invention.

[0027] A disadvantage has been that the structure stamp is exposed to different stresses during embossing of the structures and during separation of the structure stamp from the embossing material, as a result of which the spacing between the structures of the structure stamp varies, resulting in a suboptimal dimensional stability of the structures produced in the embossing material. Summary of the Invention

[0028] The object of the present invention is therefore to provide an improved device and an improved method for embossing structures, in particular microstructures and / or nanostructures, which no longer have the disadvantages of the prior art and by means of which it is possible in particular to ensure automated and faster processing of substrates with embossed structures having improved dimensional stability.

[0029] This object is achieved by the subject matter of the present invention. The invention has several advantageous developments. All combinations of at least two features given in the description and / or the drawings also fall within the scope of the present invention. Given value ranges also disclose values ​​within the stated limits as limiting values ​​and can be claimed in any combination.

[0030] According to the invention, a device for embossing a structure into an embossing material is provided, comprising a structure stamp for embossing the structure into the embossing material, wherein the structure stamp can be kept under a constant local strain during embossing and separation from the embossing material.

[0031] Furthermore, the invention provides a method for embossing a structure into an embossing material, wherein a structure stamp embosses the structure into the embossing material, wherein the structure stamp is held under a constant local strain during embossing and separation from the embossing material.

[0032] The characteristic "constant" in the sense of the invention means that the local strain is at least approximately the same at every location of the structure impression. This is understood to mean that the local strain varies by at most 100 ppm relative to the mean value.

[0033] Preferably, an embossing roller is provided for pressing the structure of the structure stamp into the embossing material, wherein the embossing roller has a driver for lifting the structure stamp after embossing. Advantageously, an additional separating device can be omitted.

[0034] Preferably, a device is also provided in which the embossing roller together with the structural stamp moves from an end position on a separation track after embossing or can move back to a starting position for embossing again. Advantageously, the next embossing process can thus be started without interruption.

[0035] The present invention relates in particular to a device for imprinting microstructures and / or nanostructures using a structural stamp, wherein the structural stamp has improved handling properties, wherein the structural stamp has improved dimensional stability, wherein the device enables the structural stamp to be separated from the substrate in a structurally space-saving manner, and wherein the dimensional stability of the structural stamp is maintained during the imprinting process.

[0036] Another invention relates to another device according to the invention for embossing microstructures and / or nanostructures, wherein the structures are transferred to the embossing material solely by means of deformation of the structural stamp, without the need for force being applied from the back by means of a fluid roller or an embossing roller, and wherein the dimensional stability of the structural stamp is maintained during the embossing process.

[0037] The present invention also relates to a method for embossing microstructures and / or nanostructures, wherein the embossing method achieves improved dimensional stability of the embossing and the dimensional stability of the stamp by separating the substrate from the structure stamp in a controlled manner. In particular, the material stresses in the structure stamp are controlled during embossing and during separation. This results in the local strains of the structure stamp remaining constant, and thus the dimensional stability of the structure stamp, in particular the dimensional stability of the embossed structure, is improved.

[0038] The application regulates the effect of forces on the stamp, especially during the separation process, whereby the structure stamp, the carrier and the embossed piece are subjected to less load. The limited load improves the embossing quality and extends the service life of the structure stamp.

[0039] The new separation method performed with the separation device according to the application has less space requirements compared to conventional separation methods. Thereby, especially the basic area of the entire device can be reduced, which in turn reduces the costs in the clean room.

[0040] The first embodiment of the device according to the application comprises a substrate holder, a structure stamp to be molded, a fixing element for the structure stamp, a stamping roller and a separation device and the components listed below.

[0041] The device also comprises guiding elements and a measurement system and energy and medium supply devices (CDA, vacuum, process gas, cooling water, etc.) and positioning and movement devices (drivers, brakes, fixing elements, clamps, especially active vibration-damping mounts, etc.) and a central control and / or regulation unit, especially implemented as a computer and / or FPGA.

[0042] Furthermore, a substrate coated with embossing material is essential for the method according to the application.

[0043] At least two manufacturing operating states can be assigned to the device for embossing: an embossing state and a separation state. In the embossing state, the structure stamp is molded. In the separation state, the structure stamp is separated from the molded substrate.

[0044] The device uses different components in the embossing state and in the separation state, to which a division of the device parameters is appropriate. The features of the device are listed as far as possible in the order of the components listed above and the relationships between the components are described.

[0045] Substrate holder

[0046] The substrate holder can fix the substrate coated with embossing material. For this purpose, different fixing mechanisms can be used.

[0047] The fixing mechanism can be

[0048] • a mechanical fixing mechanism, especially a clamp

[0049] • a vacuum fixing mechanism, especially with individually controllable vacuum paths or interconnected vacuum paths

[0050] • an electrical fixing mechanism, especially an electrostatic fixing mechanism

[0051] • an electronically controllable and / or regulated fixing mechanism

[0052] • a magnetic fixing mechanism

[0053] • adhesive fixing means, in particular Gel-Pak fixing means

[0054] • fixing means with adhesive, in particular steerable, surfaces, and / or.

[0055] A vacuum fixing means is a preferred fixing type. The vacuum fixing means is preferably composed of a plurality of vacuum paths which are discharged at the surface of the sample holder. The vacuum paths can preferably be steered and / or adjusted individually. Preferably, the plurality of vacuum paths are purposefully combined, grouped into vacuum path sections which can be steered individually and thus can be evacuated or perfused. However, each vacuum section is independent of the other vacuum sections. Thus, the possibility of building vacuum sections which can be steered individually is obtained. The vacuum sections are preferably designed in a ring shape. Thereby, a purposeful, radially symmetrical, in particular from the inside to the outside, fixing and / or detachment of the substrate from the sample holder can be achieved. This is advantageous for rotationally symmetrical substrates.

[0056] For other shaped substrates, for example rectangular substrates or panels, a division of the vacuum sections parallel to the substrate side faces is advantageous. It is particularly advantageous if the configuration or switching method of the vacuum sections is configured in a shape- conforming manner to the shape of the respective substrate. This enables a flexible use of the sample holder for different substrate shapes. The substrate can in particular have a non-planar or free-form face to be imprinted.

[0057] The substrate can have an arbitrary shape, but is preferably circular. In particular, the diameter of the substrate is standardized in industry. For wafers, the industry standard diameters are 1 inch, 2 inches, 3 inches, 4 inches, 5 inches, 6 inches, 8 inches, 12 inches and 18 inches. However, an embodiment according to the present application can in principle process any substrate, regardless of its diameter. Rectangular substrates are often referred to as panels.

[0058] Structural stamp and fixing for structural stamp

[0059] The structural stamp preferably has the following characteristic properties: the stamp side contains the structure to be molded as a negative. When the structural stamp is molded, a depression of the imprinting mass is produced by the elevations of the structural stamp. Correspondingly, the topography of the stamp face will contain the negative of the desired topography.

[0060] The back side of the structural stamp is the face opposite the stamp side. The imprinting roller preferably rolls along it on the back side of the structural stamp.

[0061] At least two opposite ends of the structural stamp are used to fix the structural stamp in the device. Fixing elements are preferably used to fix the structural stamp.

[0062] In a particularly preferred embodiment, the fixing element can be partially materially and partially functionally integrated into the structural impression.

[0063] The structure stamp is fixed in the device with the stamp side pointing in the direction of the substrate holder. It is envisaged that the substrate coated with the embossing compound is fixed on the substrate holder.

[0064] The actual positioning task is to align the stamping side of the stamp with the substrate coated with the stamping compound. This is achieved by positioning the fixing means of the structured stamp relative to the substrate holder in the device. Since the embodiments of the devices described vary, it is preferred to focus here on the actual positioning, stamping, and separation tasks. The equipment parameters required for this can be easily derived from the parameters in the design, construction, and operation of the device.

[0065] During the relative movement, the structured impressions are aligned relative to the substrate or, more accurately, relative to the substrate holder, and the structured impressions are aligned with one another.

[0066] In the further text, different parameter groups are disclosed. Many parameter groups are related to the statistical properties of accuracy and precision.

[0067] Accuracy is understood as systematic error. Systematic error is the deviation between the expected value of a parameter, determined from a sample set, and the true value of the population. The higher the accuracy, the smaller the deviation, and therefore the smaller the systematic error.

[0068] Precision is understood as the scatter of the measured variable around the expected value of the sample set. The higher the precision, the smaller the scatter.

[0069] Prior to embossing, the structured stamp is preferably clamped flatly and uniaxially on the surface of the embossing material by means of fixing elements. The structured stamp is preferably adjusted to an angle of less than 10 degrees, preferably less than 6 degrees, particularly preferably less than 3 degrees, and in the best case less than 1 degree with respect to the substrate, and ideally parallel to the substrate.

[0070] The free distance between the structured stamp and the embossing material before embossing is less than 1 mm, preferably less than 500 micrometers, particularly preferably less than 50 micrometers. In a particularly preferred embodiment, the free distance between the structured stamp and the embossing material before embossing is less than 10 mm, particularly preferably less than 25 micrometers, very particularly preferably less than 10 micrometers, and in the best case less than 5 micrometers.

[0071] In a preferred embodiment, the structured impression can be reinforced by a carrier, in other words supported by the carrier.A thin, optically homogeneous, mechanically isotropic material, in particular a film, can be used as a carrier.

[0072] The following materials and / or their combinations and / or their blends can be used as the material of the carrier:

[0073] Glass (borosilicate, fluorine, sapphire)

[0074] Polydimethylsiloxane (PDMS)

[0075] Perfluoropolyether (PFPE)

[0076] ·Cage-type polysilsesquioxane (POSS)

[0077] Polydimethylsiloxane (PDMS)

[0078] Tetraethyl orthosilicate (TEOS)

[0079] Poly(organo)siloxane (silicon)

[0080] Thermoplastics

[0081] Thermosetting plastics

[0082] ·polymer

[0083] Elastomer

[0084] Polyimide (PI)

[0085] Polyethylene terephthalate (PET)

[0086] Polyamide, and / or

[0087] ·carbon.

[0088] All listed materials can also be used as fiber materials.

[0089] In a preferred embodiment, the carrier can be produced in particular by a prototyping method, such as, in particular, casting, injection molding, rolling, extrusion blow molding.

[0090] The material of the structural impression is at least one of the following materials or a combination and / or a mixture thereof:

[0091] Polydimethylsiloxane (PDMS)

[0092] Perfluoropolyether (PFPE)

[0093] ·Cage-type polysilsesquioxane (POSS)

[0094] Polydimethylsiloxane (PDMS)

[0095] Tetraethyl orthosilicate (TEOS)

[0096] Poly(organo)siloxane (silicon)

[0097] Thermoplastics

[0098] Thermosetting plastics

[0099] • polymer

[0100] • elastomer.

[0101] In a particularly preferred embodiment of the assembled structure stamp, the carrier can achieve advantageous functional integration by means of spatial profiling. The fixing element can be produced at least partially together with the carrier, in particular in a prototype forming process.

[0102] In this embodiment, the thickness of the carrier is variable. The carrier comprises one part, namely one region having a first, in particular uniform, thickness in the region of the structure stamp, which is molded, and another part, namely another region having a second, variable thickness, which can in particular be configured as a fixing element.

[0103] In another embodiment, a sensor, in particular a force-measuring sensor or an optical refractive sensor, preferably a birefringence sensor, a polarization sensor, is arranged at a first, uniform-thickness edge region of the structure stamp. The electrical contact of the evaluation electronics and / or the optical coupler is correspondingly integrated on the fixing element in another region in the volume of the carrier.

[0104] In this advantageous embodiment, the strain properties of all listed components (carrier, sensor, supply, structure stamp, contact) match one another.

[0105] imprint roller

[0106] The imprint roller is preferably a cylindrical or barrel-shaped (spheroid) body having a well-defined axis of rotation and a peripheral surface. In other words, the imprint roller is a roller, i.e. a roller that is driven at least on one side, guided, in particular supported, at least at one end. The support of the imprint roller effects the rotation of the imprint roller, the guidance of the imprint roller effects the translation of the imprint roller along the guide.

[0107] In a particular embodiment, the imprint roller is a spheroid roller with which non-planar substrates can be imprinted.

[0108] For imprinting, the peripheral surface of the imprint roller is brought into contact with the back side of the structure stamp in order to mold the imprint face of the structure stamp in the imprint mass.

[0109] The surface quality of the peripheral surface is preferably produced at least in a polished, preferably lapped, quality. In other words, regardless of the material used, the imprint roller is preferably "as smooth as glass".

[0110] The imprint roller is supported or guided at least at one end in order to be able to carry out the movements required for imprinting.

[0111] The peripheral surface diameter of the embossing roller according to the application is greater than 10 mm, preferably greater than 15 mm, particularly preferably greater than 30 mm, quite particularly preferably greater than 70 mm, and in the best case greater than 120 mm. Smaller substrates or smaller structure stamps are preferably embossed with embossing rollers having a smaller diameter compared to large-area substrates and / or face plates.

[0112] The embossing roller performs the embossing starting from a specific starting position, for which the corresponding adjustment loops, measurement systems and drives are switched and adjusted. The embossing roller displaces the structure stamp so that the structure stamp comes into contact with the embossing mass. For this purpose, in particular a linear force of the embossing roller is applied to the rear side surface of the structure stamp. The embossing roller preferably displaces the structure stamp in such a way that the capillary forces of the embossing mass are sufficient to attract the structure stamp.

[0113] The ratio of the capillary forces of the embossing mass applied to the structure stamp to the force applied to the structure stamp by the embossing roller, calculated as linear force, is 100:1, preferably 50:1, particularly preferably 10:1. The resultant force resulting from the capillary forces and the linear force of the embossing roller, possibly additionally the force of gravity, achieves the prototyping workability of the embossing mass. In a further embodiment, the force ratio of the capillary forces to the force applied to the structure stamp by the embossing roller is 2:1, particularly preferably 1:1, quite particularly preferably 1:5, in another case 1:10.

[0114] In a further preferred embodiment, the embossing force is at least partially adjustable, particularly preferably adjustable, in particular constant.

[0115] The adjustment of the embossing force can be achieved by means of an adjusted adjustment and readjustment of the embossing roller in the normal direction of the back side of the embossing stamp. Here, an embossing force of between 0 N and 50,000 N, preferably between 0 N and 10,000 N, particularly preferably between 0 N and 1,000 N, quite particularly preferably between 0 N and 150 N, is generated as a linear force.

[0116] The embossing force can be influenced, in particular adjusted, by means of a mass of the embossing roller, which is variably adjustable, which is uniformly distributed as such. The mass of the embossing roller can be adjusted using a weight, such as a liquid, metal balls, sand, etc., which is additionally added in the embossing mass. Furthermore, the influence, in particular adjustment, of the embossing force can be influenced by adjusting the capillary forces between the structure stamp and the embossing mass. For this purpose, the viscosity parameters can be influenced by means of the solvent content and / or the temperature and / or additives.

[0117] The viscosity of the embossing mass is between 0.01 centipoise and 10,000 centipoise, preferably between 1 centipoise and 500 centipoise, particularly preferably between 2 centipoise and 300 centipoise.

[0118] The temperature of the printing material (preferably also the temperature of the substrate and substrate holder) is between 0°C and 300°C, preferably between 15°C and 120°C, particularly preferably between room temperature (especially 20°C) and 75°C.

[0119] During embossing, the temperature fluctuations of the embossing material are less than + / -5 K, preferably less than + / -3 K, particularly preferably less than + / -1 K, very particularly preferably less than + / -0.5 K, and in the optimal case less than + / -0.1 K.

[0120] The embossing compound may contain flow agents and / or free-radical scavengers and / or free-radical reducers and / or oxygen inhibitors as additives, in particular substances based on modified acrylates.

[0121] In a first embodiment, the embossing roller is a roller element that is driven on at least one side and guided, in particular supported, at both ends. In the case of a roller element that is preferably stiff, the outer circumference is preferably constructed from an elastic material. The elastic material of the embossing roller preferably increases the planar or rolling friction with the structured stamp. Furthermore, the surface of the embossing roller, which comprises an elastic material, in particular a cross-linked polymer structure, can reversibly absorb and enclose microparticles on the back side of the structured stamp, ensuring that the particles do not affect the embossing result.

[0122] In particular, the embossing roller can be signaled by means of a signal change (color, birefringence, conductivity) that cleaning is necessary due to particles entrapped during embossing.

[0123] In this document, no distinction is made between structured stamps without a carrier and structured stamps with a carrier, so that the listed properties and features can relate to embodiments with and without a carrier.

[0124] The embossing roller is preferably supported so as to be secured against tilting.

[0125] In a first embodiment, the embossing roller is supported on one side by at least two guide elements spaced apart from one another, so that a continuous rolling friction occurs as the supporting friction. The drive side is the unsupported side. In other words, the embossing roller is supported on one side by two bearings so that it can be moved along the guide rail, while on the other side it has a coupling, in particular a releasable coupling, for a force connection or a stroke-adjustable coupling.

[0126] In a second embodiment of the embossing roller, both ends of the embossing roller are supported and driven synchronously. This leads to minimization of shear forces along the embossing roller, in particular on the structure stamp.

[0127] During the embossing process, the structure stamp is molded in the embossing mass on the substrate surface. In particular, the embossing roller can be rolled along the length of the structure stamp at a constant speed or can be moved with a specific speed profile. In particular, the achieved prototyping workability remains constant. This can be achieved by varying the speed of the embossing roller and / or by varying the embossing force or embossing pressure, preferably under the influence of a regulation.

[0128] The embossing roller preferably performs a rolling motion on the back side of the structure stamp and here at least partially performs the prototyping work of the embossing mass.

[0129] In an embodiment of the device, the guide of the embossing roller is at least one linear guide, preferably at least one prismatic linear guide. The guide straight line of the linear guide preferably deviates from the ideal value by less than 500 micrometers, preferably by less than 100 micrometers, particularly preferably by less than 10 micrometers, quite particularly preferably by less than 1 micrometer, with regard to the total length.

[0130] A plane is formed with the further guide of the embossing roller. The plane formed, the embossing plane, preferably coincides with the substrate surface to be embossed. The embossing plane is particularly preferably formed parallel to the substrate surface and offset by the thickness of the structure stamp.

[0131] In a particularly preferred embodiment of the device, the guide of the embossing roller comprises two linear guides, which can be calibrated by + / - 15 degrees, preferably by + / - 10 degrees, particularly preferably by + / - 5 degrees, so that the embossing plane can be adjusted and readjusted. The calibration comprises adjustment means for the parallel position of the linear guides to each other. The parallelism is better than 1 degree, preferably better than 0.5 degrees, more preferably better than 0.1 degrees.

[0132] In a further preferred embodiment of the device according to the application, the guide of the embossing roller is configured as a trajectory of the substrate surface to be embossed, which is in particular non-planar. The embodiment of the guide of the embossing roller thus described enables the embossing roller to be guided substantially parallel to the substrate, which results in a particularly constant residual layer thickness of the embossing mass.

[0133] In order to be able to use the device in a variety of ways, it is provided that the guide of the embossing roller can in particular be implemented to be exchangeable automatically. The guide of the embossing roller here forms the respective ideally looking substrate shape.

[0134] If the guide of the embossing roller is used to guide the embossing roller during embossing, the guide serves as a control curve for the embossing, in other words the embossing roller has an embossing track.

[0135] The stamping track can contain specific positions, which are defined as a starting position or an end position during stamping. The method described below starts stamping from the starting position and ends stamping in the end position.

[0136] At the end of the embossing process, the embossing roller can initially remain in a specific end position or return to a defined starting position.

[0137] In another embodiment, the embossing roller is passively set in rotation during the embossing process, ie the friction between the embossing roller and the structure stamp is sufficient to move the embossing roller over the characteristic length of the structure stamp during embossing, in particular with little slip, preferably without slip.

[0138] In another embodiment according to the invention, the embossing roller has at least two drives which move the embossing roller in a manner that is independently adjustable from one another, preferably in a manner that is expediently synchronous with one another in terms of translation and rotation.

[0139] Thus, embossing operations, such as doctoring, or in particular slip corrections can be carried out, so that the rotational speed of the embossing roller, the resulting angular velocity, and the feed speed can be coordinated and adapted to one another in a controlled drive arrangement.

[0140] The slip correction is a measure of how much the pressing of an elastically structured stamp, particularly an elastic embossing roller, into an elastic embossing material deviates from the ideally calculated process parameters. Deviations can be interpreted as slipping or jamming, i.e., rotations that are faster or slower than the ideal angular velocity calculated for the feed rate. The slip correction measure describes the actual friction conditions. Slip is preferably kept to a minimum using a controlled slip correction.

[0141] Separation devices and separation mechanisms

[0142] After the embossing material has solidified, or at least after the embossing material has begun to solidify, the structured stamp is separated from the embossing material. A condition for successful separation of the structured stamp from the embossing material can be expressed as low adhesion of the embossing material to the structured stamp, such that after separation, the embossed embossing material has a shape stability (pattern fidelity) such that deformation of the embossing material is less than 5%, preferably less than 2%, particularly preferably less than 1%, and ideally less than 0.01%.

[0143] During separation, the structural stamp and the substrate move away from each other in a relative motion. Therefore, it is irrelevant whether the substrate or the stamp is lifted off from each other for successful separation. In this regard, the movement of the structural stamp is appropriate.

[0144] The separating device can comprise a so-called separating rail for the embossing roller as an especially spatial guide.

[0145] After the embossing process, the embossing roller can be moved from a defined end position along a separating track. In other words, the separating track is a control curve, i.e., a track in space. The separating track guides the embossing roller at least away from the substrate, preferably away from the structure stamp, so that the embossing roller is lifted from the substrate and returned essentially parallel to the embossing track to a defined starting position.

[0146] The embossing roller has a correspondingly designed entrainment element which receives the fixing element of the structural stamp and entrains the fixing element on the separating track. The structural stamp is thereby entrained and separated from the embossing material.

[0147] In other words, the structure stamp is driven, in particular from a horizontal position, by means of a driver, preferably in a confined space, along with the embossing roller, to achieve separation at a large separation angle. The material tension in the structure stamp remains constant.

[0148] The separation angle is greater than 0 degrees, preferably greater than 30 degrees, particularly preferably greater than 90 degrees, very particularly preferably greater than 120 degrees, and in the optimal case greater than 160 degrees.

[0149] The driver can establish a positive connection between the fastening element of the structural die and the embossing roller. The following basic structural concepts can be used as different embodiments of the driver, either uniformly (designed identically at both ends) or mixed, so that the driver is different at each end of the embossing roller:

[0150] The fit of the ball on the plane,

[0151] The fit of the ball on multiple planes, such as V-grooves,

[0152] The fit of the tapered part in the tapered hole,

[0153] ·Columnar parts-U-shaped groove matching,

[0154] · Column-V groove fit, or constructed as a keyway,

[0155] The fit of the column within the column,

[0156] Prismatic elements on a flat surface,

[0157] Prismatic elements within prismatic elements,

[0158] Magnet and counterpart, also constructed as switchable electromagnets,

[0159] Bayonet connection,

[0160] Control curves and columns (self-locking control curves, spirals),

[0161] and / or

[0162] ·Releasable spring lock.

[0163] The driver can establish a friction-locking connection with the embossing roller by friction.

[0164] The driver can establish an electromagnetic and / or permanent magnetic and / or electrostatic and / or vacuum connection with the embossing roller. Preferably, no solid material contact occurs between the embossing roller and the driver. In other words, the driver and the embossing roller can be coupled by means of a fluid flow or (electro)magnetic or electrostatic coupling and can be moved by the correspondingly implemented operation.

[0165] Controlled detachment is achieved by optimizing the following parameters:

[0166] The height of the separation track relative to the stamped track,

[0167] regulated pulling force of the embossing roller on the separating rail, which is applied to the fixing element and the structural stamp,

[0168] · Length of separation track,

[0169] The trajectory of the structural die on the separation track (the control curve of the movement),

[0170] Electrostatic voltage to repel the structure stamp from the cured stamping material,

[0171] · Selection / influencing of surface properties, in particular reduction of surface energy by appropriate coatings, and / or

[0172] With knowledge of the thermo-mechanical time constants of the individual components, regulation of the separation temperature and / or thermal support of the separation process can be achieved, in particular by targeted changes in the structure geometry while exploiting the differences in thermal expansion of the substrate, the stamping compound, and the structure stamp. Thermo-mechanical gradients can be used to design faster and more efficient separation processes.

[0173] As an example of a separation process, the rapid heating of the substrate and the stamping material causes the substrate and the stamping material to expand, so that the unheated structure stamp can be separated from the stamping material with less force than in the isothermal state.

[0174] After the structure stamp has been successfully separated from the substrate, the guide return mechanism in particular brings the structure stamp back to the stamping position and fixes the structure stamp accordingly.

[0175] Alternatively, the embossing roller guides the structure stamp into the embossing position and moves it into a defined starting position without further affecting the structure stamp.

[0176] Method 1

[0177] In a first method for molding a structure stamp in an imprinting mass on a substrate according to the application, the following method steps are provided.

[0178] The coating of the substrate with the imprinting mass and the transport and fixing of the substrate on a substrate holder, the fixing of the structure stamp in said are understood as preparatory method steps and are not described in detail.

[0179] In a first method step, the imprinting roller is moved over the substrate wetted with the imprinting mass and a material- engaging contact is established between the structure stamp and the imprinting mass.

[0180] In a second method step, the imprinting roller is moved over the feature length of the structure stamp and the structure stamp is molded in the imprinting mass, in particular over the entire area. In other words, the imprinting roller is moved along an imprinting track.

[0181] In a third method step, the imprinting mass is crosslinked. The curing of the imprinting mass can be effected as an overall area. Alternatively, a following energy source can gradually initiate the curing.

[0182] In a fourth method step, the imprinting roller reaches a specific end position of the structure stamp.

[0183] In a fifth method step, the imprinting roller is coupled to the drive element at the structure stamp.

[0184] In a sixth method step, the imprinting roller is moved along a separation track together with the structure stamp coupled at the imprinting roller, thereby separating the structure stamp from the, in particular cured, imprinting mass.

[0185] In a seventh method step, the structure stamp is completely separated from the imprinting mass. Thereafter, the imprinted substrate is unloaded.

[0186] In an eighth method step, the structure stamp and the imprinting roller are brought into the respective starting position. In one preferred embodiment, the imprinting roller is moved in the opposite direction back to the separation track, the structure stamp is placed into the imprinting position, the drive element or drive elements are disengaged and the imprinting roller is moved back into the starting position.

[0187] In another embodiment, the drive element is disengaged, a mechanism brings the structure stamp into the imprinting position and the imprinting roller is moved a defined further path back into the starting position.

[0188] Further device according to the application (offset structure stamp)

[0189] A second embodiment of the device according to the application is a further development of the device according to the first embodiment of the application according to the application, the device having a regulated, constant strain pre-tensioning mechanism for the structure stamp. The stamp preferably has a carrier.

[0190] The structural stamp is clamped, in particular with a regulated preload, in particular with a controlled, in particular regulated, constant strain. During the production of the structural stamp and the use of the structural stamp for molding the impression material, a constant strain of the structural stamp is maintained.

[0191] If constant strain cannot be maintained, the deviation from the constant strain is maintained at a strain value of less than 120 μm (resulting in 100 ppm) over a reference length of 200 mm, preferably less than 1 μm (resulting in 5 ppm) over a reference length of 200 mm, particularly preferably less than 500 nm (resulting in 1.6 ppm) over a reference length of 300 mm, and very particularly preferably less than 50 nm (resulting in 16 ppb) over a reference length of 300 mm.

[0192] This allows for better dimensional stability of the embossed structure. In particular, the local dimensional stability of the embossed structure is maintained by a constant local strain in the structure stamp. In other words, the goal is to minimize strain changes during embossing or separating the structure stamp, which leads to improved dimensional stability.

[0193] For the present invention and for the basic concept according to the invention, a constant local strain is understood to mean a one-to-one effect of a device that preloads the structural impression, in particular a controlled preloading force.

[0194] In particular in the case of structural impressions composed of polymers or elastomers, a constant local strain can be achieved by means of a controlled preload, thereby taking into account relaxation of the structural impression material and improving and increasing the dimensional stability of the structural impression.

[0195] In a longitudinal section along the embossing mold, the fixed points and the variable embossing points form a right triangle, which in particular has a hypotenuse of constant length. The predefined geometric conditions define an elliptical path of constant strain for the structural stamp.

[0196] The error between the elliptical path of the structure stamp following the embossing roller and the plane used for embossing is less than 5%, preferably less than 3%, and particularly preferably less than 1%. This is achieved by designing the geometric conditions, in particular by the spacing of the fixing points being 1.5 times the embossing length, preferably twice the embossing length, and particularly preferably four times the embossing length.

[0197] In order to avoid errors in the elliptical path, it is advantageous according to the invention to use a correspondingly abutting elliptical base.

[0198] In particular, so-called virtual reality glasses, curved displays, such as television sets or computer screens, can appear as applications. The technology according to the application can also be applied to interactive windows, in particular displays integrated into windshields (in particular curved shape) or interactive side windows for rail vehicles or buses (in particular planar shape).

[0199] The impression roller in particular pre-tensions the structure stamp between the fixing elements in a regulated manner. The structure stamp (at the time of the impression) lies against the impression roller with a contact angle of less than 181 degrees, preferably less than 120 degrees, particularly preferably less than 90 degrees, quite particularly preferably less than 45 degrees, in the optimum case less than 30 degrees.

[0200] In a further preferred embodiment, the contact angle between the structure stamp and the impression roller is less than 5 degrees, preferably less than 3 degrees, particularly preferably less than 1 degree.

[0201] The large contact angle is achieved by means of the impression roller at the controlled separation of the structure stamp. At the time of the impression, the small contact angle described above is preferred, in particular below 30 degrees. The structure stamp is preferably clamped uniaxially.

[0202] In a further preferred embodiment of the device, the pre-tensioning of the structure stamp is adjusted by means of a control loop and an actuator, in particular a linear actuator on the structure stamp, and the local strain of the structure stamp remains constant. Here, the spacing of the fixing points from one another is adjusted such that the elliptical trajectory of the pre-tensioned structure stamp is variable and always describes a tangent to the impression plane in any position of the impression roller. Here, a constant strain of the structure stamp is maintained. Thus, an impression plane or a so-called free-form surface can be imprinted.

[0203] This is achieved by a structural approximation of the respective ellipses and planes via elastic and / or guided elements in a control chain or regulation loop. In a particularly preferred embodiment, the planar shape to be molded on the impression mass by the structure stamp is adjusted by a regulated strain and targeted length change of the two sides of a theoretical right-angled impression triangle.

[0204] The free spacing between the structure stamp and the impression mass (before the impression) is less than 5 mm, preferably less than 1000 micrometers, particularly preferably less than 500 micrometers, quite particularly preferably less than 100 micrometers, before the impression.

[0205] In a further particularly preferred embodiment, the free spacing between the structure stamp and the impression mass is further reduced to less than 50 micrometers, preferably less than 20 micrometers, particularly preferably less than 10 micrometers, quite particularly preferably less than 5 micrometers. The free spacing relates to the minimum value between the structure stamp and the impression mass, so that the effects of the flexure and / or free suspension and / or electrostatic attraction of the structure stamp, in particular, as well as the effects of transient device vibrations are also taken into account.

[0206] A relative feed movement of the structured stamp relative to the stamping material and relative to the substrate establishes contact between the stamping material and the structured stamp.

[0207] The embossing compound is cured simultaneously, preferably locally, particularly preferably linearly, and particularly preferably simultaneously with the slit projection of the curing radiation. Slit projection can be understood as a slit lamp or an oscillating laser beam. The oscillation speed is at least 100 times, preferably at least 1,000 times, and particularly preferably 10,000 times higher than the speed of the embossing roller, so that the curing radiation acts over a large area and does not cure separate lines.

[0208] In another embodiment of the device, the curing of the embossing material occurs locally at controlled intervals. The duration of the intervals between application of the curing radiation and absence of the curing radiation is determined in an iterative process, taking into account the minimization of the thermal load on the embossing material and the structural stamp. Such regulation is known to those skilled in the art as pulse width modulation. However, other known regulation methods may also be used.

[0209] In a particularly preferred embodiment of the device according to the invention, at least the embossing roller and the source for curing are functionally integrated into one unit, thereby creating an embossing roller unit.

[0210] The embossing roller unit can include at least one embossing roller, in particular a support roller of identical design, and a radiation source with a projection mechanism. In this preferred embodiment of the embossing roller, the embossing roller is designed as a double-constructed, spaced-apart roller pair, with the curing device located between the roller pairs. The first roller moving in the embossing direction is considered the embossing roller, in particular the continuously operating curing device crosslinks the embossing material, while the subsequent embossing roller acts as a support roller to achieve controlled separation of the substrate stamp from the cured embossing material.

[0211] In another embodiment, the embossing roller unit can include at least one embossing roller and a support roller. A radiation source, in particular a heat source, can be integrated into the support roller. In other words, one roller of the embossing roller unit serves as the embossing roller, while the other roller, as a heated roller, serves as a thermal curing device and is integrated into the embossing roller unit as a curing device. Another embodiment can include a radiation source for crosslinking radiation, in particular a UV light source. In this case, the support roller is designed to be transparent to the crosslinking radiation.

[0212] In a particularly advantageous embodiment, the spacing between the support roller and the embossing roller in the embossing roller unit can be varied, particularly in a controlled manner, to adjust the tension state of the structured die. If the rollers are closer together, the structured die is less prestressed than if the rollers are at their maximum spacing. In particular, a pantograph with minimal, preferably no, prestressing can be used as the adjustment mechanism. However, any self-sustaining and play-free adjustment device can be used.

[0213] To adjust the preload of the structural die, strain sensors, in particular strain gauges, can be integrated into and / or onto the structural die. In another embodiment of the structural die, strain gauges are attached to the structural die. Furthermore, the force-measuring sensor for the tensioning force of the structural die can be compared with actual values, in particular from multiple strain gauges. The measured stress state of the structural die can be considered a controlled variable. The positions of the rollers relative to one another, the position of the embossing roller unit, and / or the position or tension of the structural die's holding device, adjusted individually or in combination, can be used as controlled variables related thereto.

[0214] The time constant of the control is preferably 1 / 10, particularly preferably 1 / 100, particularly preferably 1 / 1000 of the time constant of the fastest movement of the device. The control speed (speed of the control element) is as fast as the fastest movement of the device.

[0215] The controller is preferably implemented as a computer program or routine. The controller is particularly advantageously designed for precision (preload accuracy, positioning accuracy, dimensional accuracy) and speed, but overshooting or over-increasing the control variable from the setpoint is undesirable. The control parameter derived from the difference between the setpoint and the actual value of the stress in the structure stamp is designed such that "upward swings," in particular harmonic oscillations, are prevented at any point in time during the embossing and separation processes.

[0216] The mechanical stress of the structural stamp is between 0.001 MPa and the corresponding yield strength of the structural stamp (and / or the carrier), preferably between 1 MPa and 2 MPa. If the yield strength of the structural stamp is less than the yield strength of the carrier, the listed parameters apply to the structural stamp. Generally, the mechanical stress parameters are applicable to materials with a lower yield strength. This avoids overloading the structural stamp.

[0217] The mechanical stress of the structured stamp is particularly preferably regulated. During embossing or when separating two successively embossed substrates, the mechanical stresses of the structured stamp should deviate as little as possible from one another over time. In other words, according to the present invention, the preload of the structured stamp can be varied during the embossing and / or separation process, and a regulated, variable preload can be used. The minimum deviation in the preload is therefore relevant to the reproducibility of the same method steps. Thus, the mechanical stress of one embossed substrate can be adjusted together with the mechanical stress of another embossed substrate with the lowest possible reproducibility.

[0218] A similar situation applies to maintaining the mechanical stress as constant as possible when separating the embossed substrate from the structure stamp.

[0219] The deviation of the mechanical stress is less than 10%, preferably less than 5%, particularly preferably less than 2%, based on the set values, in particular the set values ​​of the corresponding method step.

[0220] The deviation of the strain of the structural stamp from the ideal state of dimensional stability (and the dimensional stability coupled therewith) is less than 100 ppm, preferably less than 10 ppm, particularly preferably less than 100 ppb, very particularly preferably less than 10 ppb, and in the optimal case less than 5 ppb.

[0221] Embossing with an apparatus according to the invention having an embossing roller unit, in which the prestressing of the structure stamp for a constant local strain of the structure stamp is adjusted in a controlled manner, is considered to be an independent method according to the invention.

[0222] Other devices according to the invention (semi-elastic structured stamp without embossing roller)

[0223] A third, particularly preferred embodiment of the device comprises at least one substrate holder, a structure stamp to be molded, a fastening element for the structure stamp, and a prestressing mechanism. The method according to the invention requires a substrate coated with embossing compound. The properties of the structure stamp described above can be transferred accordingly to a structure stamp with an embossing roller.

[0224] The structural impression consists of at least two areas, which realize the functional division of the structural impression:

[0225] There are molding regions, which are preferably arranged symmetrically approximately about half the characteristic length of the structural stamp, and holding regions, which are preferably formed at least at both ends of the structural stamp.

[0226] The molding region of the structural stamp is preferably configured to conform to the shape of the substrate.The holding region of the structural stamp surrounds the molding region at least on two sides.

[0227] On the stamp side, the molding area contains the structured surface of the structural stamp to be molded. The molding area can contain alignment marks for positioning devices (aligners) and / or exposure equipment, version numbers, control characters as binary or QR codes, wherein the control characters or alignment marks do not necessarily need to be molded into the stamping compound.

[0228] In further embodiments of the structure stamp, alignment marks, version numbers, control characters for the positioning device (aligner) and / or exposure device can be applied, in particular unchangeably, to the side opposite the stamp side.

[0229] The molded area is preferably configured to be at least optically homogeneous and free of bubbles and extraneous shadows, and mechanically isotropic. If the structured stamp contains a carrier, the properties of the structured stamp also relate to the carrier. The carrier preferably has a uniform thickness.

[0230] In another embodiment of the structured stamp, the molding region is designed such that, in addition to the structures to be molded of the structured stamp, the targeted structuring of the carrier or the structured stamp contributes to minimizing and / or homogenizing the residual layer thickness of the imprinted structures on the substrate. Preferably, variations in the residual layer thickness of less than 50 nanometers, particularly preferably less than 10 nanometers, and very particularly preferably less than 1 nanometer are produced.

[0231] In other words, the structure-dependent residual layer thickness of the embossed structure can be adjusted.

[0232] In applications utilizing a lift-off process after embossing, a minimized residual layer thickness is generally preferred.

[0233] For optical applications, in particular diffractive optics, waveguides (diffractive optical elements, DOEs), a defined, adjustable, dimensionally stable residual layer thickness is preferred.

[0234] It can be easily seen that the absolute value of the residual layer thickness can be greater in the case of structure sizes in the order of millimeters than in the case of structure sizes in the order of nanometers.

[0235] In a preferred embodiment of the structural impression, the boundary between the holding region and the molding region is not designed as a defined line, but rather is to be understood as regions having functions that interact with one another.

[0236] The holding region has as its main task the task of holding the structural impression in the device. The holding region may have the same material properties as the molding region, but may differ therefrom in shape and / or thickness and / or additional functionality and / or stiffness and / or information content.

[0237] In a first embodiment, the holding region is a material continuation of the molded region having at least approximately the same thickness and rigidity.

[0238] In a second embodiment, the holding region is a material continuation of the mold region with a varying mold region thickness and correspondingly varying rigidity. This embodiment is particularly symmetrically designed as a half-wedge or wedge, so that the structural stamp can be prestressed with an adjustable material tension with minimal notch stress.

[0239] In a third embodiment, the holding region is a material continuation of the molded region with the constructed solid hinge.

[0240] A fourth embodiment of the holding region may result in a combination of the second and third embodiments of the holding region: the holding region comprises a solid hinge and a wedge-shaped element for fixing the structural impression in the device.

[0241] A fifth embodiment of the retaining region is designed to be wedge-shaped and asymmetrical in cross-section. The retaining region has at least two flat support surfaces on the stamping side. In particular, the flat support surfaces are offset relative to the molding surface of the structure stamp, so that the molding region of the structure stamp, when freely supported, does not contact the support surface on which the support surface rests, oriented in the direction of gravity. In other words, the structure stamp rests on the support surface at its edge, while the stamping side does not touch the support surface and is held there by its inherent rigidity.

[0242] The rigidity of the holding region and the molding region is in particular sufficient so that the structured stamp, which rests freely on the contact surfaces, preferably on the contact surfaces at both ends of the stamp, does not touch the contact surfaces with the molding region despite being suspended as a rigid plate.

[0243] The placement surface allows for simple, contamination-free storage of the structural impression outside the device. A further advantage of this embodiment is that the pre-set orientation of the structural impression defines its orientation in the device. The further asymmetry of the structural impression can be used to ensure a uniquely aligned position and orientation of the structural impression in the device. These measures implement the key and lock principle.

[0244] The combination of the fifth embodiment with the second and / or third embodiment is considered particularly advantageous.

[0245] The structural stamp is fixed in the device, in particular, by means of form-fitting fixing elements. In addition to the fixing function, the fixing elements and the structural stamp are further functionalized to correspond to one another. In particular, a precisely correct installation position of the structural stamp is achieved using the key-lock principle, in particular by means of asymmetrically positioned shaped elements or an asymmetrical design of the structural stamp.

[0246] The design of the structure stamp according to the application is in particular the result of simulations and numerical approximations (finite element method, FEM), wherein the parameters of the simulated embossing process are used to optimize the residual layer thickness of the embossing material influencing the dimensional stability and service life of the structure stamp. If the structure stamp thickness is not uniform, the stiffness and the path length of the crosslinking, curing radiation or heat transfer are suitably designed according to the numerical optimization. Thereby, a complex yieldable articulation for the structure stamp can be realized, which not only enables a uniform constant pre-tension of the structure stamp but also an almost contourless embossed structure.

[0247] In particular, the semi-elastic structure stamp can thus be designed, simulated and manufactured, wherein the material strain of the structure stamp is preferably kept constant and, with a corresponding adaptation of the material thickness and / or material stiffness of the structure stamp, the molding area of the structure stamp maintains a higher flatness and / or higher dimensional stability during embossing than the holding area. In particular, a solid articulation consisting of the stamp material / carrier material of the structure stamp enables the deformation of the structure stamp for embossing by means of the force action of the structure stamp. The structure stamp can in particular take two forms, with or without force action, which have as a result the resting state of the structure stamp or the pre-tensioned stable position of the structure stamp for embossing.

[0248] The structure stamp is preferably designed such that the neutral fiber of the structure stamp remains permanently on the embossing surface. According to the application it is conceivable that the molding surface is subjected to a constant tensile stress, which does not change during the embossing process (from the start of the structure manufacturing of the structure stamp). For this purpose, the device can be embodied accordingly adjustable.

[0249] It is thereby achieved that the embossed structure to be transferred of the structure stamp is manufactured without mechanical stress and thereby the greatest variable force is the separation force. The separation force acts approximately normal to the embossed structure, thereby enabling a better dimensional stability of the embossed structure and the structure stamp.

[0250] The device according to the application receives the structure stamp in a stamp holder with translational and rotational degrees of freedom and a positioning system. The structure stamp and the substrate coated with embossing material are brought close to each other. The embossing is carried out by a bending of the structure stamp by a feed motion of the positioning system. The separation of the structure stamp after the curing of the embossing material takes place under reversal of the embossing motion.

[0251] In other words, the molding work of the structural stamp can be generated by a bending movement, preferably with no external forces acting on the back of the stamp surface other than gravity. In particular, the molding surface is reversibly deformed by less than 20% of a critical structural dimension, preferably less than 5%, particularly preferably less than 1%, and very particularly preferably less than 0.1% of the critical structural dimension, while the holding area performs a macroscopic movement for embossing. The bending movement of the structural stamp thus serves for embossing. The embossed prototyping work is formed by the distance traveled by the embossing force. The action of capillary forces and the bending movement of the structural stamp result in the prototyping work.

[0252] Therefore, the device can dispense with a separating device and an embossing roller. BRIEF DESCRIPTION OF THE DRAWINGS

[0253] Further advantages, features and details of the invention will be found in the following description of preferred exemplary embodiments with reference to the drawings.

[0254] In the attached figure:

[0255] Figure 1 A schematic structural diagram showing a first embodiment of the device according to the present invention;

[0256] Figure 2a A schematic structural diagram showing a first embodiment of a second device according to the present invention;

[0257] Figure 2b A schematic structural diagram showing a second embodiment of a second device according to the present invention;

[0258] Figure 3 A schematic structural diagram showing another device according to the present invention;

[0259] Figure 4a A schematic structural diagram showing a structural impression;

[0260] Figure 4b Show the basis Figure 4a A schematic structural diagram of the application of a structural stamp in a device according to the present invention;

[0261] Figure 5 Show the basis Figure 4b A schematic structural diagram of the application of a structural stamp in a device according to the present invention;

[0262] Figure 6 A schematic structural diagram showing a third embodiment of the structural stamp;

[0263] Figure 7 Show the basis Figure 6 Schematic structural diagram of the use of a structural stamp in a further device according to the present invention. DETAILED DESCRIPTION

[0264] In the figures, the same components or components having the same functions are denoted by the same reference numerals.

[0265] Figure 1 A schematic structural diagram of a first embodiment of the present invention shows a device 1 for embossing according to the present invention. A structured stamp 4 is held under constant strain by means of a fixing element 3. The constant, in particular adjustable, strain of the structured stamp is indicated by the arrow of the fixing element 3. To this end, the device 1 adjusts, in particular regulates, a mechanical force that, as a mechanical stress in the structured stamp 4, achieves a constant local strain.

[0266] The substrate coated with the embossing compound (not shown) is fixed on the substrate holder 5 and - after the structure stamp 4 is brought into contact with the embossing compound - the structure stamp 4 is formed in the embossing compound. For a complete prototyping operation, the embossing roller 6 presses the structure stamp 4 into the embossing compound.

[0267] To separate the structure stamp 4 from the substrate, a separating device 2 is used, here shown as a separating track.

[0268] The separating device 2 is structurally connected to the embossing track between a starting position S and an end position E. If the embossing roller 6 is at a distance between S and E, the structured stamp 4 is molded, i.e., embossed. If the embossing roller 6 is outside the embossing track on a separating track between E and S, a driver (not shown) accordingly drives the structured stamp 4, thereby separating the structured stamp 4 from the substrate.

[0269] In particular, in order to support the separation process, the substrate holder 5 can also be moved. The optional relative movement is indicated by the arrows.

[0270] Figure 2a A schematic structural diagram of a first embodiment of the second device according to the invention is shown. The structural stamp 4' is preferably fixed in a fixed position in a device for embossing, not shown, by means of a fixing element 3'. The embossing roller 6' pre-tensions the structural stamp 4' under a constant strain, so that the structural stamp 4' can emboss a substrate, not shown, coated with embossing material. The substrate is fixed to a substrate holder 5'. The substrate holder 5' is feedable, in particular feedable in an adjustable manner. This can be used to adjust the embossing force and for adjusting the normal force when separating the structural stamp 4' from the substrate. In a further embodiment, the substrate holder 5' is not feedable, so that the further feed movement is performed by the structural stamp, the fixing element, etc.

[0271] In particular, the embodiment shown is suitable for embossing curved, preferably oval, substrate surfaces. This is symbolically indicated by the curvature of the substrate holder 5'.

[0272] Figure 2b A schematic structural diagram of a second embodiment of a second device according to the present invention is shown. The structured stamp 4" is fixed in a device for embossing (not shown) by means of a fixing element 3". The fixing element 3" is coupled to a movement and measuring device (not shown), so that the local strain of the structured stamp 4" can be kept constant against the action of the embossing roller 6" and can be corrected. Figure 2a The elliptical error of the embodiment is reduced. The embossing roller 6" preloads the structured stamp 4" with a constant strain and a controlled tensioning force, so that the structured stamp 4" can emboss a substrate (not shown) coated with embossing material. The substrate is fixed to a substrate holder 5", which can be advanced, in particular in a controlled manner. In other embodiments, the feed movement to the stationary substrate holder is implemented as a relative movement.

[0273] Figure 3 A schematic structural diagram of an embossing roller unit 7 according to the invention and components of a device according to the invention (not shown) is shown. The embossing roller 6'" and the supporting roller 8 are installed in a movement, calibration and guide unit 10, in particular in a manner that can be adjusted by a regulating system (not shown). In addition, the embossing roller unit 7 contains a radiation source 9, which is preferably positioned between the embossing roller 6'" and the supporting roller 8, for curing the embossing material. In particular, in the gap between the embossing roller 6'" and the supporting roller 8, the radiation from the radiation source 9 reaches the structured embossing material (not shown) via the structured stamp 4'" which is adjustably prestressed, in particular under constant strain. The substrate (not shown) is fixed to a substrate holder 5'", wherein the substrate holder 5'" can be designed to be feedable in an adjustable manner.

[0274] In another embodiment of the embossing roller unit 7, the preload of the structured stamp 4'' can be adjusted by, in particular, varying the distance between the embossing roller 6'' and the support roller 8 in a controlled manner. In other words, the embossing roller 6'' and the support roller 8 spread the structured stamp 4'' at least approximately flat on the variable surface. This makes it possible to additionally correct the Figure 1 、 2a , 2b and the ellipticity error of the device according to the invention and bring about better dimensional stability.

[0275] Figure 4a A schematic structural diagram of a structural die 4iv with an integrated fixing element 3iv is shown, wherein the mold area A and the holding area H with their respective functions are indicated. In the holding area H, the structural die 4iv includes an edge area designed according to the key-lock principle for form-fitting fixing of the structural die 4iv. In particular, a device (not shown) allows for free-standing clamping of the fixing element 3iv, so that the structural die 4iv is loaded with a constant preload during all method steps.

[0276] Figure 4bA schematic structural diagram of a structural stamp 4v with an integrated fixing element 3v in a device (not shown) is shown, wherein the structural stamp 4v is kept under constant strain, in particular in an adjusted manner. The substrate (not shown) is fixed to a feedable substrate holder 5v. The relative movement of the structural stamp 4v with the molding area A and the substrate holder 5v establishes contact between the structural stamp 4v and the stamping material, so that the structural stamp 4v is molded in the stamping material. The integrated fixing element 3v can fix the structural stamp 4v in the device, in particular without parasitic forces, preferably without constraints, and particularly preferably according to the key-lock principle. In other embodiments, the substrate holder 5v can be fixed in position, and the device with the structural stamp performs other required movements.

[0277] Figure 5 A schematic structural diagram shows another embodiment of a structural die 4vi with integrated fixing elements 3vi. To minimize sudden changes in material stress in the structural die 4vi, an at least semi-wedge-shaped, preferably (not shown) wedge-shaped, edge region is created in the retaining region of the structural die 4vi. This advantageously achieves an embodiment free of notch stresses.

[0278] Advantageous embodiments can be achieved by a doubly asymmetrical design of the structural mold 4vi. The asymmetry of the structural mold 4vi is preferably utilized in order to be able to distinguish between upper and lower installation positions by structural features and to avoid incorrect sideways installation in the device.

[0279] The further asymmetry of the structured impression 4vi can be characterized in a further, in particular “left-right”, plane coordinate direction such that a laterally inverted installation position of the structured impression is prevented.

[0280] This embodiment of the double asymmetrical design of the structural stamp 4vi can be used in all structural stamps according to the invention. The asymmetrical or double asymmetrical design of all structural stamps according to the invention allows the use of the key-lock principle.

[0281] Figure 6 A schematic structural diagram of a third embodiment of the structural stamp 4vii is shown. This embodiment is similar to Figure 4a and 5 The embodiment shown in . The structural stamp 4vii preferably has a material-integrated solid joint F. The structural stamp 4vii can therefore have different strengths, but can also have a flat molding area, in particular for roller-free embossing processes.

[0282] Figure 7 Show the basis Figure 6schematic structural view of a third embodiment of a structure stamp as part of a not shown device according to the application. The not shown device can mold the structure stamp 4viii in a not shown embossing stock of a substrate under constant strain, in particular with a variable, regulated pre-tension, by means of a stationary fixing element 3viii which can be positioned and moved in a regulated manner. A substrate holder 5viii can fix the substrate and move it in a regulated manner.

[0283] In other embodiments, a stationary substrate holder 5viii is used and the relative movement between the substrate stamp 4viii and the substrate is performed by the substrate stamp.

[0284] The structure stamp 4viii can configure a substantially flat molding area by means of different strengths and solid hinges, wherein the embossing process can be introduced by bending the solid hinges F of the structure stamp, preferably without an embossing roller (see for this Figure 6 ).

[0285] List of reference signs

[0286] 1 device for embossing

[0287] 2 separating device

[0288] 3, 3', 3", 3"', 3iv, 3v, 3vi, 3viii fixing element for a structure stamp

[0289] 4, 4', 4", 4"', 4iv, 4v, 4vi, 4vii, 4viii structure stamp

[0290] 5, 5', 5", 5"', 5v, 5viii substrate holder

[0291] 6, 6', 6", 6"' embossing roller

[0292] 7 embossing roller unit

[0293] 8 support roller

[0294] 9 radiation source

[0295] 10 movement, alignment and guide unit

[0296] S starting position

[0297] E end position

[0298] H holding area

[0299] A molding area

[0300] F solid hinge

Claims

1. A device (1) for embossing a structure into an embossing material, comprising a structure stamp (4, 4', 4", 4'", 4iv, 4v, 4vi, 4vii, 4viii) for embossing the structure into the embossing material, wherein: The structural stamp (4, 4', 4", 4"', 4iv, 4v, 4vi, 4vii, 4viii) can be kept under a constant local strain during embossing and separation from the embossing material, characterized in that the device (1) has an embossing roller (6, 6', 6", 6"') for pressing the structure of the structural stamp (4, 4', 4", 4"', 4iv, 4v, 4vi, 4vii, 4viii) into the embossing material, wherein the embossing roller (6, 6', 6", 6"') has a driving member for lifting the structural stamp (4, 4', 4", 4"', 4iv, 4v, 4vi, 4vii, 4viii) after embossing.

2. The device (1) according to claim 1, wherein The embossing rollers (6, 6', 6", 6'") can be moved together with the structure stamp (4, 4', 4", 4'", 4iv, 4v, 4vi, 4vii, 4viii) after embossing from an end position (E) back to a starting position (S) for further embossing on a separating track.

3. A method for embossing a structure into an embossing material, wherein: A structural stamp (4, 4', 4", 4"', 4iv, 4v, 4vi, 4vii, 4viii) embosses the structure into the embossing material, wherein the structural stamp (4, 4', 4", 4"', 4iv, 4v, 4vi, 4vii, 4viii) is kept under a constant local strain during embossing and separation from the embossing material, and is characterized by an embossing roller (6, 6', 6", 6"') for pressing the structure of the structural stamp (4, 4', 4", 4"', 4iv, 4v, 4vi, 4vii, 4viii) into the embossing material, wherein the embossing roller (6, 6', 6", 6"') has a driving member for lifting the structural stamp (4, 4', 4", 4"', 4iv, 4v, 4vi, 4vii, 4viii) after embossing.

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