Device and method for manufacturing micro or nanostructures

Abstract

Apparatus and method for manufacturing micro and / or nanostructures.

Description

Technology Field

[0001] The present invention relates to an apparatus and method for manufacturing micro and / or nanostructures. Background Technology

[0002] In conventional technology, micro and / or nanostructures are created by photolithography and / or with the help of imprint lithography. Recently, imprint lithography has become the dominant method. With the help of imprint lithography, it is possible to emboss micro and / or nanometer-sized structures onto a material using a stamp. The material is an embossing material applied to a substrate. The problem to be solved

[0003] These imprint processes have become increasingly important in recent years because they can be performed faster, more efficiently, and at a lower cost than many photolithography processes.

[0004] After the embossing material is deposited, alignment of the structured stamp with respect to the substrate occurs. Then, the structured stamp and the substrate come into close proximity. The structure of the structured stamp is formed on the embossing material. Before removing the structured stamp from the embossing material, the embossing material hardens. This hardening occurs thermally and / or by electromagnetic radiation.

[0005] Apart from modified or extended mask aligners, there are also separate imprint devices designed for special embodiments. These devices are mostly very precise alignment systems capable of aligning the stamp with the substrate with higher precision. Additionally, these devices can generate a vacuum and are equipped with special distribution systems, etc.

[0006] Embossing technology operates with hard or soft stamps. Among embossing lithography techniques, the primary preference is always the use of so-called soft stamps. This is due to the ease of stamp fabrication, an efficient embossing process, the excellent surface properties of each stamp material, low production costs, the reproducibility of embossed products, and, above all, the possibility of elastic deformation of the stamp during removal from the embossing and molding positions. Stamps made of polymers, particularly elastomers with micro or nanostructured surfaces, are used in soft lithography to create structures ranging from less than nm to up to > 1000 μm.

[0007] Elastomer stamps are produced from the negative of a master. The master stamp is a hard stamp made of metal, plastic, and / or ceramic, produced once through a correspondingly expensive process. Then, any desired number of elastomer stamps can be generated from the master. The elastic modulus of quartz reaches approximately 100 GPa. In comparison, the elastic modulus of polymers (hard and soft polymers) is tens of times smaller; therefore, compared to quartz, the latter is referred to as "soft" (soft lithography). Using elastomer stamps enables conformal and uniform contact over large surfaces. They separate relatively easily from the master stamp and the embossed product. To ensure excellent separation between the stamp and the substrate, the stamp surface has the lowest possible surface energy. For example, an anti-adhesion coating is often necessary or advantageous.

[0008] To perform a soft lithography process, an elastomer stamp can be supported via a carrier. For example, glass carrier substrates of different thicknesses are currently used. Using a thick glass substrate causes the elastomer stamp to lose at least some of its flexibility. Meanwhile, the flexibility of the stamp can be controlled by the selection of the carrier. The use of a rigid carrier generally makes it difficult to separate the stamp from the substrate after the embossing process.

[0009] Similarly, thin substrates according to the prior art require a substrate carrier for better handling. Known soft lithography processes include, for example, micro and / or nano contact printing (μ / nCP) and nanoimprint lithography (NIL).

[0010] In nanoimprint lithography, the curing of the embossing material can occur via heat or UV radiation. In both cases, a structured stamp is pressed into the embossing material. The structured stamp and the substrate are pressed together by pressure to enable high-resolution surface structuring. UV-NIL allows for operation with lower contact pressure compared to thermal NIL, and the process can take place at room temperature. The most critical parameters in the NIL process are temperature (especially for thermal NIL), indentation pressure, and adhesion between the embossing material and the structured stamp.

[0011] Soft stamps and less soft stamps, particularly elastomer stamps, can be deformed by the pressure applied during the nanoimprint process. This deformation depends on the pressure. Such deformation is expected to have a greater impact on smaller structures and be more pronounced in softer stamp materials. Deformation or distortion of micro and nanostructures caused by contact pressure is found in the cured embossing material of the embossing substrate, thereby reducing the quality and reproducibility of the embossing process.

[0012] When the structured stamp and / or substrate is too stiff, external pressure, particularly contact pressure, is required to achieve equal or seamless contact between the structured stamp with the stamp structure and the substrate with the embossing material. In the prior art, an actuator device is used that includes an individually controllable or adjustable actuator that acts on the structured stamp and / or substrate as a force serving to transmit the stamp structure and consequently becomes perpendicular to the substrate contact surface.

[0013] For larger areas, it is difficult to accurately distribute pressure evenly across the entire contact surface and compensate for irregularities. Consequently, non-uniform structuring may occur during embossing. Non-uniformity of the stamp surface also affects the quality of the embossing process. Furthermore, gas inclusions during pressure-induced embossing and associated embossing defects are known in the prior art.

[0014] Embossing defects that may occur in NIL include, for example, cracks, irregularly filled stamp structures (i.e., containing air), and uneven lacquer layer thickness.

[0015] Capillary force lithography (CFL), a less widespread soft lithography process, is based on using capillary forces to fill stamp structures without external pressure. In Adv. Funct. Mater. (2002) 12: 405-413, CFL is described in detail by eponym HH Lee. The elastomer stamp makes conformal contact with the substrate. However, to fill the cavity, the viscosity of the embossing material must be very low. Therefore, CFL often requires higher temperatures and / or a high solvent ratio in the embossing material and a solvent atmosphere. Because PDMS is permeable to solvents and gases, almost exclusively pure PDMS is used as the stamping material for CFL. During embossing with a PDMS stamp, the cavity is filled under the influence of capillary forces, and the solvent of the embossing material can diffuse through the PDMS stamp and escape. The epoxy material SU-8 has been established as the embossing material for CFL. Problems such as the swelling of PDMS in solvent-based processes and significant scaling in heat-based processes mean that CFLs are performed only at the laboratory scale and industrial implementations using imprint devices are unknown. Additionally, embossing materials are typically thermally crosslinked in CFLs.

[0016] US 7,442,336 B2 specifies an apparatus and method for embossing a substrate with an embossing material, wherein the substrate and the stamp are slowly brought together to a defined distance so that the intermediate space is filled with the embossing material due to capillary force. The external force is kept as small as possible depending on the characteristics of the embossing material, the thickness of the layer to be embossed, and the size of the substrate surface.

[0017] In US 8,871,048 B2, a flexible elastomer stamp is used to keep external pressure as low as possible.

[0018] MIMIC (Micro-forming in capillaries) also uses capillary forces to create structures using PDMS stamps. However, in MIMIC, a PDMS stamp with a relief structure is pressed onto a substrate. Consequently, a three-dimensional hollow structure is formed between the stamp and the substrate. When a monomer solution is applied in front of the stamp, the capillaries naturally fill the space. After curing, the stamp can be removed from the substrate. The three-dimensional structure of the polymer remains on the substrate.

[0019] In conventional technology, a particular problem is that the elastic properties of soft stamps cause deformation or warping of micro and nano structures. Deformation and warping of micro and nano structures caused by contact pressure are found in the cured embossing material of the embossing substrate, thereby degrading the quality and reproducibility of the embossing process.

[0020] Soft stamps can be deformed during the nanoimprint process due to applied pressure. Such deformation depends particularly on the pressure. Additionally, gas inclusions and associated embossing defects when embossing with pressure are known in the prior art.

[0021] If the structured stamp and / or substrate are too stiff, external pressure, i.e., contact pressure, is required to achieve conformal and smooth contact between the structured stamp and the substrate with the embossing material. Consequently, deformation due to pressure may occur, which can degrade the quality of the embossing process. means of solving the problem

[0022] Accordingly, the objective of the present invention is to specify a substrate, as well as an apparatus and a method, that at least partially, and particularly completely, eliminate the disadvantages mentioned in the prior art.

[0023] The above-mentioned problem is resolved by the features of the independent claim. Advantageous developments of the invention are presented in the dependent claim. Any combination of at least two features given in the specification, claims, and / or drawings also falls within the scope of the invention. Values ​​within the specified limits of the specified value range are deemed to be disclosed as limited values ​​and may be claimed in any combination. If a feature disclosed in relation to the device is also recognized as a feature of the method, the latter should also be applied according to the method, and vice versa.

[0024] In the following, structuring and embossing are understood to refer to the production of micro and / or nano structures. In particular, contact pressure must not be generated during embossing.

[0025] The present invention describes a method and apparatus for producing structures of micro and / or nanometer size. Above all, the present invention is based on the idea of ​​using a very thin, particularly flexible substrate and using capillary forces to solve the aforementioned technical problems in production. After contact is made between the embossing material and the structured stamp, the fixation of the substrate is preferably at least partially released by at least one controllable fixing element, and as a result, the embossing process is preferably started.

[0026] Accordingly, the present invention relates to a method and apparatus for bringing a structured stamp and an embossing material into equal contact without using external pressure in an embossing process, or without contact pressure between the structured stamp and the embossing material.

[0027] Accordingly, the present invention relates to a method for manufacturing a micro and / or nanostructure having the following steps in at least the following order:

[0028] a) a step of fixing a substrate with an embossing material on a substrate receiving device,

[0029] b) Contact step between the embossing material and the structured stamp,

[0030] c) a step of at least partially releasing the fixation of the substrate,

[0031] d) Curing step of the embossing material,

[0032] f) Step of removing embossing material from the structured stamp.

[0033] In addition, the present invention relates to an apparatus for manufacturing micro and / or nano structures by the aforementioned method, wherein a substrate having an embossing material can be fixed on a substrate receiving device and a structured stamp can come into contact with said substrate. The fixation of the substrate can be at least partially released, the embossing material can be cured, and the embossing material can be removed from the structured stamp.

[0034] In addition, the present invention relates to articles having micro and / or nano structures, and the micro and / or nano structures are manufactured by the method according to the present invention and the apparatus according to the present invention.

[0035] In a preferred embodiment of the present invention, the substrate is provided to be flexible and thus at least partially conformal to the structured stamp, particularly after release from fixation or during the structuring of the embossing material. The substrate is composed of a particularly thin and / or partially flexible material so as to advantageously assume the structure of the partially structured stamp during production. The substrate may also not conform to the structured stamp or may fully conform to it. After the embossing material is cured, the cured substrate embossing material forms a unit, particularly. Thus, the substrate can advantageously assist the embossing process and prevent embossing defects. Additionally, the thin and flexible substrate can be deformed during the production process. In particular, the substrate is advantageously pulled toward the structured stamp in a conformal manner by the action of capillary forces and deforms accordingly. Furthermore, due to the flexibility, a uniform contact preferred during production is possible. The flexibility of the substrate advantageously enables careful and uniform embossing without embossing defects. Additional degrees of freedom are advantageously obtained by releasing the fixation, and as a result, the thin and flexible substrate supports the production process in the desired manner, particularly due to the action of capillary forces. After release, the substrate becomes free on the substrate receiving device. Since the embossing material and the substrate are pulled toward the structured stamp, it is conceivable that the substrate may be partially or completely lifted from the substrate receiving device, particularly by capillary forces. In particular, due to the flexibility of the substrate, no external pressure is required to transfer the structure to the embossing material. Therefore, the substrate can particularly compensate for irregularities, thereby further improving the quality of the embossing process.

[0036] In another advantageous embodiment of the present invention, after at least partial release of the substrate fixation, at least partial separation of the substrate from the substrate receiving device is provided to occur particularly by relative movement. By relative movement between the substrate receiving device and the substrate and / or between the substrate receiving device and the stamp receiving device and / or by capillary force. The separation can particularly create a gap between the substrate and the substrate receiving device. However, it can also be conceived that the release of the fixation does not lead to separation of the substrate or the creation of a gap. Furthermore, it is possible to create a space between the substrate and the substrate receiving device after at least partial release of the fixation, particularly by an actuator. The gap created by the actuator is advantageous to the process, particularly regarding material properties. In particular, due to surface tension and capillary force, the substrate continues to adhere to the embossing material or is pulled toward the structured stamp, thereby creating an advantageous degree of freedom for the substrate. In response to the arrangement of the substrate receiving device relative to the stamp receiving device, additional forces, particularly gravity, may act during the embossing process. In particular, a gap may already be partially created during contact by suction applied to the substrate due to capillary forces acting specifically on the embossing material. However, preferably, the gap is not created until at least the partial release of the fixation. As a result of the gap, the reproducibility and efficiency of the embossing process, particularly multiple embossing steps performed simultaneously and / or in parallel, can be advantageously improved. Additionally, the substrate can be deformed and adapted to the structured stamp as the degrees of freedom increase. In particular, embossing defects can thus be prevented.

[0037] In another advantageous embodiment of the present invention, the structured stamp is provided to be a hard stamp or a soft stamp. In particular, the structured stamp may include a soft or hard embossed structure. A hard stamp is understood to mean, in particular, a master stamp. Thus, the soft stamp and the micro and / or nano structure can be produced efficiently and cost-effectively through a production process, particularly through a suitable selection.

[0038] Process parameters and technically appropriate production materials. In addition, deformation of the structured stamp, particularly deformation of the embossing structure of the structured stamp, can be prevented by the appropriate selection of the structured stamp, and uniform and reproducible embossing can be achieved.

[0039] In another advantageous embodiment of the present invention, the embossing material is provided to be structured without pressure and / or contact pressure, particularly by capillary forces. Thus, deformation of the structured stamp can be advantageously reduced, and in particular, prevented. Furthermore, the reproducibility of the embossing process can be increased, and embossing defects can be prevented. Additionally, this method is more efficient and cost-effective. The advantageous production of a structure without external pressure can advantageously improve the material properties of the embossing material after curing, such as strength values ​​or surface properties. Furthermore, the substrate can be advantageously maintained after separation. An advantage of the above method is that it can also be used for the production of micro and / or nano structures, whereby the smaller the size of the structure, the stronger the capillary force acts. Thus, embossing can be performed without mechanical pressure, where the embossing material is advantageously accommodated by the structure and thus can adapt particularly well to the structure. Advantageously, when contact occurs between the embossing material and the structured stamp, only contact or wetting of the structured stamp, particularly the surface of the embossing structure, is required.

[0040] In another advantageous embodiment of the present invention, a substrate having an embossing material is provided to be fixed on a substrate receiving device by a controllable fixing element arranged particularly in a substrate receiving device.

[0041] The fixation is released by vacuum and / or low pressure and / or by at least one controllable fixing element, particularly by turning off the low pressure and / or generating overpressure. At least one fixing element can advantageously fix a substrate on a substrate receiving device, particularly fixing the substrate at a specific point. The fixing element may be a vacuum track that is arbitrarily arranged or set on the surface of the substrate receiving device, particularly in a circular or spiral shape. The fixing element may preferably generate overpressure and / or underpressure. The force resulting therefrom may be arbitrarily introduced, particularly on the substrate, particularly on the side of the substrate facing the substrate receiving device. In particular, for example, curvature of the substrate may be created. The substrate is fixed, for example, at the edge of the substrate receiving device by low pressure, and overpressure is generated by another fixing element, whereby the substrate is advantageously raised, particularly at the center. In this way, the contact can be adjusted, particularly during contact. Additionally, at least one fixing element can advantageously prevent embossing defects, particularly gas inclusions, by technically convenient and controlled partial fixation or release. During the release of the fixation, the fixing element may release the substrates individually and / or in groups in a specific order. Thus, the production of the structure can be advantageously initiated, particularly in a specific area. The fixing element is preferably configured so that the removal of the substrate from the structured stamp into the cured embossing material can be assisted by the fixing element. The embossing process can be advantageously initiated by the fixing element. During the release or liberation of the substrate, capillary forces can act particularly advantageously on the embossing material and / or the substrate.

[0042] Through fixed elements, meticulous and uniform production of the structure is possible. In addition, the removal of the substrate can also be performed in a particularly careful and advantageous manner. The substrate receiving device and the substrate preferably have a wafer shape.

[0043] In another advantageous embodiment of the present invention, the fixation of a substrate and at least partial release of the substrate fixation are controlled, particularly by controlling at least one controllable fixing element, so that the release or separation of the substrate occurs at a specific time after contact between the embossing material and / or the structured stamp and the embossing material. At least one fixing element is preferably controlled by a control unit and thus advantageously influences the release time of the substrate fixation and thus influences the separation or release of the substrate at a specific time. In particular, the release of fixation may be provided to be initiated at different points by a plurality of controllable fixing elements. Thus, the time and place for releasing the fixation can be controlled particularly advantageously. The control unit preferably controls at least one fixing element according to a value, particularly a value provided by a sensor.

[0044] In another advantageous embodiment of the present invention, the structured stamp is provided to be configured such that, after at least partial release of fixation, the embossing material and / or substrate are adapted to the structured stamp or withdrawn toward the structured stamp. In particular, stamping is performed in a conformal manner without external pressure by capillary force. The structured stamp, in particular, the embossing structure of the structured stamp, is configured such that the structure is advantageously transferred to the embossing material, particularly by capillary force. In particular, the contact surface of the structured stamp that contacts the embossing material during contact is configured to enable uniform contact, particularly over the entire area. Advantageously, the structure or concave and / or protrusions of the embossing structure of the structured stamp are arranged so that structuring can occur without pressure. The embossing structure to be transferred is configured such that the substrate can be adapted to match the structure, particularly after release of fixation. Advantageously, the structured stamp is also designed for advantageously easy removal. In particular, the structured stamp or the embossing structure can be used repeatedly. Thus, the production process can be performed efficiently and repeatedly in a continuous manner using the same structured stamp.

[0045] In another advantageous embodiment of the present invention, a substrate is provided to be held by an embossing material, particularly by capillary forces and / or surface tension, after contact and / or at least partial release of fixation. Thus, the substrate is at least partially adhered after release of fixation caused by the embossing material on the structured stamp. In particular, the substrate may be separated from the substrate receiving device due to the capillary forces acting on the embossing material. As a result of the release of the substrate or the release of fixation, the substrate is retained, wherein the substrate can be advantageously adapted to the structured stamp. In particular, the substrate can be advantageously applied freely and uniformly to the embossing structure. Irregularities can also be compensated for. All existing gas inclusions, in particular, can escape. Thus, there is an advantage of improved quality of the embossing process.

[0046] In another advantageous embodiment of the present invention, micro and / or nanostructures are provided to be created side-by-side in a plurality of layers and / or next to each other in a step-repeating process. The multilayer build-up is performed repeatedly, particularly until there is no longer any minimum required flexibility of the substrate. Thus, the process can be performed more efficiently and cost-effectively. Additionally, different layers can be created side-by-side. Furthermore, multiple functional structures can be created over a large area or next to each other in a constant embossing process. Thus, the widest variety of products, particularly structured films, can be efficiently produced by this method. In particular, the structured stamp has the advantage of being reusable because the resistance of the structured stamp increases in the absence of contact pressure, or because the structured stamp can be used over multiple embossing steps.

[0047] In another advantageous embodiment of the present invention, the thickness of the substrate is provided to be 1 μm to 2000 μm, preferably 10 μm to 750 μm, more preferably 100 μm to 500 μm. Using a thinner substrate can increase the flexibility of the substrate. Thus, the substrate can be much more suitable for an embossing structure and can compensate for irregularities. In addition, a larger number of layers can be created side by side because the flexibility required for more embossing steps is provided.

[0048] In another advantageous embodiment of the present invention, the viscosity of the embossing material is provided to be less than 100,000 cP, preferably less than 10,000 cP, more preferably less than 1,000 cP, and most preferably less than 500 cP. Through the use of an embossing material having a lower cP value, the fixation of the substrate, the effect of capillary forces, and conformal adaptation to the embossing structure of the substrate and / or the embossing material can be improved, in particular. Additionally, a low cP value is advantageous for correcting irregularities. Furthermore, the flexibility of the substrate is utilized in an optimal manner to improve the embossing quality. By the appropriate viscosity of the embossing material, the embossing behavior of the embossing material and, in particular, the retention of the substrate can be advantageously adjusted.

[0049] In another advantageous embodiment of the present invention, a structured stamp is provided to include an embossing structure and / or be coated with an embossing structure. Thus, the embossing stamp itself may include an embossing structure or be coated with an embossing structure, and is applied individually, particularly to an embossing process. Thus, the embossing behavior can be advantageously adjusted. In particular, the production of the structure may be individually adjusted to the process by a different embossing coating. The different embossing structure may be transferred, for example, using an embossing stamp, particularly in a step-by-step iterative process.

[0050] In another advantageous embodiment of the present invention, an apparatus for manufacturing micro and / or nanostructures is provided to perform the process described above in particular, wherein a substrate having an embossing material may be fixed on a substrate receiving device. A structured stamp may come into contact with the embossing material, the fixation of the substrate may be at least partially released, the embossing material may be cured, and the embossing material may be removed from the structured stamp. The apparatus may advantageously produce micro and / or nanostructures in particular without additional compressive force. Thus, the quality of the embossing process is improved.

[0051] In another advantageous embodiment of the present invention, the device is provided to further comprise: one or more sensors for measuring pressure, distance, and / or temperature, and / or one or more actuators for coordinating the stamp receiving device and / or substrate receiving device and the control unit, wherein the control unit controls at least one fixed element and / or at least one actuator according to a value measured particularly by at least one sensor, and the creation or reduction of the relative movement material of the structured stamp with respect to the embossed substrate, particularly the gap between the structured stamp and the substrate, can be performed in such a manner that contact can be performed particularly without pressure. In particular, the control unit is provided to trigger the actuator based on the sensor value to cause contact with the surface of the structured stamp, particularly the embossed structure surface. Thus, contact can advantageously occur without additional contact pressure. The actuator for creating the gap may be arranged with or engaged with any component, preferably the substrate receiving device and / or the stamp receiving device. Thus, it can be advantageously ensured that the production of microstructures and / or nanostructures is performed in an optimal manner. In addition, the control unit is configured such that the fixation of the substrate by the fixing element is advantageously performed, particularly during separation and removal from the molding position based on sensor values. This has the advantage of improving process quality and avoiding embossing defects.

[0052] In a less preferred embodiment of the present invention, a control device of the device is provided to come into contact with additional contact pressure by triggering a separately controllable actuator. The net force for the transfer of the stamp structure orthogonal to the substrate contact surface is < 500 N. The structured stamp may, for example, span the entire area of ​​a wafer format, or alternatively, have a defined area smaller than the substrate to be embossed, particularly in a step-by-step iterative process. The resulting pressure for the transfer of the stamp structure perpendicular to the substrate contact surface is, in particular, 50 N / mm 2 Less than, preferably 25 N / mm 2 Less than, more preferably 10 N / mm 2 Less than, most preferably 1 N / mm 2 Less than, preferably at most 0.1 N / mm 2 It is less than.

[0053] In the present invention, the substrate is very thin compared to the substrate in the prior art. For the stabilization of the substrate (or product substrate), a carrier substrate is not used, or the carrier substrate, carrier plate, or carrier film itself is thin and flexible. Therefore, the substrate to be embossed is very flexible and is mounted particularly flexibly.

[0054] The micro and / or nanoimprint process is performed with a structured stamp, preferably an elastomer structured stamp, preferably a wafer-type structured stamp. The structured stamp preferably comes into contact with a pre-lacquered substrate over its entire area, and in particular comes into contact with an embossing material provided on the substrate.

[0055] The structured stamp and the substrate are each fixed onto the receiving device of the imprint device. The fixation of the substrate to the substrate receiving device is preferably achieved with the aid of vacuum or low pressure. After alignment, the contact surfaces of the substrate and the structured stamp come into contact over the entire area. As soon as the structured stamp contacts the substrate, it is released from the substrate coated with embossing material, particularly by interrupting the vacuum. Through the effect of capillary forces, the thin, flexible substrate is pulled conformally toward the structured stamp. As a result of the flexibility of the substrate and the degrees of freedom obtained through the detachment of the substrate, the substrate can be deformed and adapted to the structured stamp. Thus, uniform contact is possible during embossing.

[0056] The substrate and the substrate stamp are fixed together by capillary force with the embossing material in between. To this end, at least the substrate, preferably the substrate and the structured stamp, must have a high degree of flexibility. Due to the viscosity of the embossing material, the intermediate space of the structured stamp is also completely filled with the embossing material due to the capillary effect.

[0057] Due to the use of capillary forces, additional external pressure and / or contact pressure between the substrate and the structured stamp are not required during the embossing or production of micro and / or nanostructures. Therefore, deformation of the structured stamp due to contact pressure is prevented, particularly. This is understood to refer to forces arising from surface tension and / or interface tension. Capillary rise and capillary collapse can be utilized, particularly during production. Additional forces, such as adhesion and gravity, may also occur during the production process. Due to the small size of micro and / or nanostructures, the fact that the effect of capillary forces or capillary pressure is greater as the size of the structure decreases can be utilized to an advantage.

[0058] The flexibility of the substrate allows for compensation for irregularities in the structured stamp and / or substrate, and also prevents additional embossing defects caused, for example, by air inclusions, so that the quality of the embossing process is very high.

[0059] By using capillary force, additional external pressure and / or contact pressure between the substrate and the stamp is not required, especially during embossing. Since no actuation device is required for force transmission, the device and the embossing process are preferably simplified.

[0060] As a result of the flexibility of the substrate and the degrees of freedom obtained from the separation of the substrate after contact without external pressure, the substrate can be deformed and can be adapted, especially to a structured stamp.

[0061] Uniform and conformal contact is possible during embossing. Therefore, a very good imprint is obtained without embossing gaps caused by uncontacted or poorly contacted areas during embossing and subsequent curing.

[0062] The proposed invention prevents deformation of the micro and / or nano structures of a structured stamp caused by contact pressure.

[0063] Since the viscosity of the embossing material is preferably between 1 and 100,000 cP, process optimization is possible through a wide selection of embossing materials or embossing lacquers and an optimal combination of substrates, stamp materials, and embossing materials.

[0064] In particular, embossing materials do not need to have low viscosity. In particular, a solvent atmosphere is not required.

[0065] Contact and embossing can be performed, in particular, at atmospheric pressure, for example, in an air or inert gas atmosphere. Other, particularly controllable process pressures, can also be considered.

[0066] Contact and embossing can be performed, in particular, at room temperature and at elevated temperatures.

[0067] The described method enables advantageously high throughput and, in particular, can reduce the unit cost per production unit.

[0068] Embossing of periodic and non-periodic micro and nano structures is possible.

[0069] Precise alignment is not absolutely necessary. The degree of alignment prior to contact between the substrate and the structured stamp can vary depending on the case, for example, by using a very precise alignment system, ranging from only approximate to fine.

[0070] Various types of flexible substrates can be used in the described method.

[0071] Embossing or production can be performed on smooth and / or rough surfaces. The roughness may vary depending on the case.

[0072] Embossing or production can be performed particularly on flat and / or curved stamp surfaces. Due to the flexibility of the substrate and mobility resulting from the detachment of the substrate after contact without external pressure, the substrate can be deformed and adapted to the stamp.

[0073] Both conductive and non-conductive UV-curing embossing materials can be used.

[0074] Both conductive and non-conductive thermosetting embossing materials can be used.

[0075] A multilayer embossing process can be performed with the proposed invention. A first layer of a flexible substrate, which has already been embossed and cured, can be re-coated with a second embossing material in an additional step, and then embossed and cured again. The production of additional layers is conceivable, particularly as long as sufficient substrate flexibility still exists. Additionally, multiple embossing steps can be performed in parallel and / or side by side, and in each case, can be combined with a previously produced substrate.

[0076] In the described method, the thickness of the embossing material on the substrate can be varied as needed, so both thin and thick layers of the embossing material can be embossed or created.

[0077] According to the proposed invention, both work stamps can be manufactured for imprint lithography, and different types of embossing materials that can generally be cured thermally or by electromagnetic radiation, particularly UV radiation, can be embossed for structuring the substrate. UV-curable embossing materials are preferably used.

[0078] The proposed invention can be used particularly in the production of the following products:

[0079] - 1D, 2D, and / or 3D diffractive optical elements (DOE),

[0080] - Microfluidic components,

[0081] - Lenses and lens systems,

[0082] - Fresnel lens,

[0083] - Biomedical elements,

[0084] - Polarizer,

[0085] - Nanostructured electrode,

[0086] - IR wave conductor,

[0087] - Angle optics for virtual reality applications,

[0088] - Fiber optic connection,

[0089] - Work stamp for imprint lithography

[0090] - etc.

[0091] The capillary effect is generated particularly by the surface tension of the liquid itself or the interface tension between the liquid and the solid surface. Capillary forces manifest in the interaction between a solid surface and a liquid, or especially between a solid where a small amount of liquid is present. The cohesive forces and adhesive forces between liquid molecules, combined with the substrate stamp resulting from the coating using embossing material placed between the substrate surface and the substrate stamp, contribute to the fact that the two surfaces maintain a state of contact after contact without the action of external forces. A thin and flexible substrate is advantageously used so that the capillary forces have a correspondingly strong effect, and the substrate is pulled conformally toward the structured stamp.

[0092] Another aspect is that the thinly coated substrate is separated as soon as the structured stamp comes into contact with the substrate. The fixation of the substrate coated with embossing material is released specifically by the release of fixation, for example, by vacuum interruption. Due to the influence of capillary forces, the thin and flexible substrate remains connected to the structured stamp in an conformal manner.

[0093] As a result of the flexibility of the substrate and the acquired degrees of freedom caused by the separation of the substrate from the substrate receiving device, the substrate can be deformed and adapted to a structured stamp. Thus, uniform contact is possible during embossing.

[0094] As a result of conformal contact, the intermediate space of the structured stamp is completely filled, particularly due to the viscosity of the embossing material and capillary effects. Capillary pressure varies especially depending on the size of the structure.

[0095] The smaller the structure, the greater the capillary pressure. Since the capillary pressure is highest in this range, high-resolution structuring is possible in a lower nm range (≤ 50 nm).

[0096] In addition, it has the advantage of preventing embossing defects caused by external contact pressure during the embossing process.

[0097] method

[0098] The substrate is very thin compared to substrates of the prior art. For the stabilization of the substrate (or product substrate), a carrier substrate is not used, or the carrier substrate, carrier plate, or carrier film itself is thin and flexible. Therefore, the substrate to be embossed is very flexible. The micro and / or nanoimprint process is performed using a structured stamp, preferably an elastomer stamp, particularly in wafer form. The structured stamp preferably comes into contact with a pre-lacquered substrate over its entire area.

[0099] The structured stamp and the substrate are each fixed, in particular, on the receiving device of the imprint device. The fixation of the substrate to the substrate receiving device preferably occurs with the help of a vacuum or low pressure. After alignment, the contact surfaces of the substrate and the structured stamp come into contact over the entire area. As soon as the structured stamp comes into contact with the substrate, it is released from the substrate coated with embossing material, particularly by interrupting the vacuum. The release process can operate over the entire area or along a predefined process. The fixing elements are controlled accordingly.

[0100] After contact occurs, when the substrate is separated from the receiving device over the entire area, the substrate continues to adhere to the structured stamp due to the capillary effect (capillary force) acting through the embossing material present between the substrate and the structured stamp. According to the present invention, no additional external pressure is required for successful embossing or production.

[0101] Due to the action of capillary forces, a thin and flexible substrate is pulled toward the stamp in an conformal manner. As a result of the flexibility of the substrate and the degrees of freedom obtained from the separation of the substrate, the substrate can deform and adapt to the stamp. Therefore, uniform contact is possible during embossing.

[0102] The substrate and the structured stamp are fixed together by capillary forces, with the embossing material placed between them. For this to happen, the substrate must have at least a high level of flexibility. Due to the viscosity of the embossing material, the intermediate space of the structured stamp is completely filled with embossing, particularly due to the capillary effect.

[0103] Therefore, the proposed invention prevents deformation of the structured stamp structure due to contact pressure. In addition, the flexibility of the substrate allows for compensation for irregularities in the stamp and / or substrate, and also prevents additional embossing defects, such as those caused by air inclusions, resulting in very high quality of the embossing process.

[0104] During the adaptation and deformation of a thin substrate to a structured stamp, gases present between the substrate and the structured stamp, particularly air or inert gases, may be expelled, allowing embossing to occur without gas inclusions. In particular, the incorporation of air or other gases can be prevented by controlled release by a fixing element that holds or secures the substrate. Favorable separation of the substrate can be achieved by single release, particularly at the fixing element, and specifically by concentrated release along the wafer surface.

[0105] After the embossing material is cured, the substrate can be fixed onto the vacuum receiving device again if necessary, and thus removal from the molding position can occur.

[0106] A method according to the present invention for embossing a thin, flexible substrate with a structured stamp for micro and / or nanostructuring comprises, in particular, the following steps, in particular the following sequence:

[0107] a) a step of fixing a substrate and a structured stamp to the corresponding receiving device;

[0108] b) A step of applying an embossing material to a substrate;

[0109] c) Approximate and / or fine adjustment steps of the substrate and structured stamp;

[0110] d) a step of initiating an embossing process by bringing the substrate into contact with the embossing material and the structured stamp, specifically by the relative movement of the substrate receiving device and / or the stamp receiving device, so that the substrate is pulled toward the structured stamp by the capillary effect and conformal contact occurs;

[0111] e) A step of releasing the flexible substrate from the substrate receiving device as soon as contact occurs. As a result of the degrees of freedom obtained in this way, the flexible substrate can be deformed and adapted to a structured stamp.

[0112] f) Curing step of the embossing material;

[0113] g) Step of removing the structured stamp and substrate from the updated fixing and molding positions of the embossed substrate on the substrate receiving device.

[0114] Embossing is preferably initiated after the contact surfaces of the substrate and the structured stamp come into contact with the embossing material, and thus, in particular, after the application of capillary force through the detachment of the substrate.

[0115] After release, the thin substrate is no longer subject to any fixation to the receiving device and can therefore be adapted to a structured stamp.

[0116] The contact preferably describes contact over the entire area. Alternatively, contact may occur at the edges or in the middle. For point contact, the curvature of the structured stamp and / or substrate is performed by a curvature means in a further embodiment according to the present invention. Contact may be advantageously aided by a particularly controlled fixed element.

[0117] In another embodiment, a step-by-step iterative process is performed. A structured stamp is used in the step-by-step iterative process in such a way that the iterative structure is applied, for example, around the perimeter of an embossing roller. The device is provided to include a curing means for curing the embossing substrate, particularly section-by-section, preferably a section corresponding to the step-by-step iterative process, particularly a section corresponding to the stamp area of ​​the structured stamp.

[0118] Substrates, structured stamps, and embossing materials

[0119] Particularly preferably, the substrate and / or substrate stamp is flexible to enable conformal contact across the entire substrate surface or the structured stamp surface. In a preferred embodiment, the substrate is very thin, so advantageous flexibility is provided. A carrier substrate is not used for stabilizing the substrate, or the carrier substrate, carrier plate, or carrier film itself is thin and flexible. Thus, the substrate to be embossed is very flexible. The thin substrate is secured to a receiving device and is easy to handle.

[0120] The substrate may have any shape, preferably circular, rectangular, or square, more preferably in the form of a wafer. The diameter of the substrate is 2 inches or more, preferably 4 inches or more, more preferably 6 inches or more, even more preferably 8 inches or more, and most preferably 12 inches or more. The term "substrate" is understood to mean a wafer in particular.

[0121] The thickness of the substrate is particularly 1 μm to 2000 μm, preferably 10 μm to 750 μm, more preferably 100 μm to 500 μm.

[0122] The structured stamp may have any shape, preferably circular, rectangular, or square, and more preferably in the form of a wafer. It is preferable that the diameter of the structured stamp generally corresponds to the diameter of the substrate.

[0123] To implement the soft lithography process, elastomeric structural stamps are used as standard, and UV-transmitting polymer stamps are preferred.

[0124] Transparent elastomer structural stamps for UV-NIL are produced from, for example, the following polymers: polydimethylsiloxane (PDMS), polyorganosilsesquioxane (POSS), perfluorinated polyester (PFPE), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), silicones such as ethylene tetrafluoroethylene, etc. A combination of multiple materials and multiple layer systems is possible.

[0125] The structured stamp is preferably fixed on a carrier (engl.: backplane), particularly a plate, most preferably a glass carrier. Materials more conceivable for the carrier are polymers and / or metals. The carrier may also be, in particular, a stamp carrier substrate.

[0126] In terms of the embossing aspect, the structured stamp has a plurality of embossing structures distributed across the entire embossing area of ​​the embossing aspect, particularly preferably in a regular arrangement. The dimensions of the individual structures of the embossing stamp are preferably in the micrometer and / or nanometer range. The dimensions of the individual structures are particularly less than 20 μm. The dimensions of the individual structures are particularly 0.1 nm to 20 μm, preferably 1 nm to 10 μm, more preferably 1 nm to 5 μm, and even more preferably 1 nm to 2 μm.

[0127] The structured stamp may include positive and / or negative profiling located on the side facing the surface of the substrate to be processed. The structured stamp may also include an embossing structure with different dimensions.

[0128] In an alternative embodiment, the structured stamp is made of a hard UV-transparent material, such as glass, quartz, or silicon dioxide. In this embodiment, the substrate must have the particularly required thin layer thickness and flexibility. In a further embodiment, the structured stamp is made of a hard material, such as silicon, a semiconductor material, or a metal such as Ni or Ti.

[0129] Embossing materials are cured, in particular, by chemical and / or physical processes. Specifically, embossing materials are cured by electromagnetic radiation and / or temperature.

[0130] Curing is preferably achieved by electromagnetic radiation, particularly preferably by UV radiation. In this case, if the embossing material is cured from the structured stamp surface, it is desirable that the structured stamp be transparent to the required electromagnetic radiation.

[0131] A corresponding radiation source is preferably arranged on the side of the structured stamp facing away from the embossing structure. Thus, the structured stamp is transparent in a wavelength range particularly from 5000 nm to 10 nm, preferably from 1000 nm to 100 nm, more preferably from 700 nm to 200 nm, and most preferably from 500 nm to 250 nm.

[0132] The optical transparency of the structured stamp is greater than 0.01%, preferably greater than 20%, more preferably greater than 50%, most preferably greater than 80%, and most preferably greater than 95%.

[0133] The viscosity of the embossing material is preferably between 1 and 100,000 cP, so that a wide selection of embossing material / embossing lacquer and process optimization through the optimal combination of substrate, stamp material and embossing material are possible. The viscosity is particularly less than 100,000 cP, preferably less than 10,000 cP, more preferably less than 1,000 cP, and most preferably less than 500 cP.

[0134] The embossing material is applied, in particular, over the entire area or as droplets at a defined distance from the substrate or the structured stamp. The embossing material is preferably applied onto the substrate. The application of the embossing material may occur before or after fixing the substrate. According to the present invention, the area may be defined with more embossing material or more droplets depending on the topography of the structured stamp or the size of the structure. The application of the embossing material may be performed, for example, with a metering device having a nozzle that can be arranged between the structured stamp and the substrate.

[0135] In another embodiment, the present invention may be used in combination with established industrial coating processes, such as spin-coating processes. The coating can be performed separately from the embossing process in a separate module. Thus, the coating of the substrate is rapid, defect-free, particle-free, and standardized across the entire area. In particular, throughput advantages and cost savings are achieved.

[0136] device

[0137] The present invention relates to a described method and apparatus for transferring a structure, particularly a micro or nanostructure, from a UV-transmitting structured stamp onto a flat surface of a substrate, particularly preferably. A substrate holder that receives a substrate on a substrate receiving surface and a region having a structured surface of a structured stamp, which may be aligned parallel to the substrate contact surface and positioned opposite thereto.

[0138] The above device may be installed in a process chamber that can be sealed against the surroundings. Thus, the process chamber can be exhausted and / or ventilated with any gas or mixture of gases. The process chamber may be exhausted to a pressure of less than 1 bar, preferably less than 10 mbar, and more preferably less than 5 mbar.

[0139] In a preferred embodiment, the method according to the present invention is performed at atmospheric pressure, for example, in an air or inert gas atmosphere.

[0140] The process chamber can be flushed with any gas or a mixture of gases. This is particularly advantageous when it is intended that embossing not occur under vacuum. A possible reason for not using a vacuum may be the high volatility of the embossing material when ambient pressure is low. Slight volatility characterized by high vapor pressure can critically contribute to contamination of the process chamber.

[0141] The gas used should have minimal interaction with the embossing material. Particularly preferably, flushing should use an inert gas that does not interact with the embossing material.

[0142] Contact and embossing can be performed at both room temperature and elevated temperature. The equipment according to the present invention has appropriate means for temperature control and heating.

[0143] In another embodiment, the contact between the substrate and the structured stamp is particularly important because defects may occur here and reproducible alignment accuracy cannot be satisfied. The device can be used with alignment for very precise and aligned embossing of different layers, for example, with the help of the Smart®View Alignment (SVA) method. At the critical stage of contact between the aligned contact surface of the substrate and the (nano)structured stamp, a more precise alignment accuracy or offset of less than 100 µm, particularly less than 10 µm, preferably less than 1 µm, most preferably less than 100 nm, and most preferably less than 10 nm is desired.

[0144] The substrate and the structured stamp are brought together in an aligned manner in the described device, and access and coordination for the micro and / or nanoimprint embossing process are performed in a controlled manner. The device preferably includes a system for non-contact wedge error compensation between the stamp and the substrate aligned in parallel according to patent specification EP2612109B1, and the access means is used for accessing the first surface toward the second surface in a translational direction (T) across the receiving surface of the receiving device until a final position is reached.

[0145] In another embodiment, approximate alignment is sufficient. Precise alignment is not particularly necessary because the thin substrate can be adapted to the structured stamp due to flexibility and given mobility resulting from separation from the substrate holder.

[0146] The substrate and the structured stamp are secured in a receiving device (English: chuck). Crucial to the receiving device is a flat receiving surface or fixing surface, particularly for fixing and securing. The receiving device for the substrate and the structured stamp is preferably a vacuum sample holder. The use of an electrostatic sample holder, a sample holder with magnetic or electric fixing devices, or a sample holder with variable adhesive properties or appropriate mechanical clamping may also be considered.

[0147] In a preferred embodiment, the substrate and the structured stamp are fixed by low pressure or vacuum on a flat, hardened surface where vacuum tracks are milled. The substrate receiving device has vacuum tracks on the entire surface or on an outer area of ​​the surface. The negative pressure channels preferably extend concentrically with respect to the center Z of the receiving device, particularly around the entire circumference, and especially in a circular manner. Thus, particularly uniform fixation is advantageously achieved.

[0148] A receiving device, particularly a substrate receiving device, preferably has vacuum tracks only in the outer region of the surface so that the substrate is secured only partially, particularly at the edge. In particular, there is a possibility of completely releasing the substrate and / or structured stamp from the receiving device. To this end, the fixation of the receiving device, particularly the vacuum maintenance, is disabled. A fixing element acting at low pressure for fixation may also act at high pressure for the separation of the substrate. According to an advantageous embodiment, to ensure the fixation of the substrate over the entire area after the embossing and curing process, the receiving device may include a second vacuum zone for the following.

[0149] When a fixed element is provided as a vacuum element, the fixed element can generate a pressure of less than 1 bar, preferably less than 0.1 mbar, more preferably less than 0.01 mbar, most preferably less than 0.001 mbar, and most preferably less than 0.0001 mbar. The fixed element can be controlled particularly individually or in groups.

[0150] The receiving device according to the present invention may alternatively or additionally include a sensor capable of measuring physical and / or chemical properties between a fixed substrate and the receiving device. Such a sensor is, for example, a temperature sensor, a pressure sensor, or a distance sensor. Additionally, it is conceivable that a plurality of different types of sensors be integrated. Furthermore, the sensor may be placed in different parts of the device. For example, a distance sensor or a pressure sensor may be placed between the receiving devices. In particular, the distance and / or acting force between a substrate having an embossing material and a stamp or stamp structure may be measured.

[0151] In addition, the contour of the receiving surface can be recessed relative to the receiving plane of the receiving surface as needed, thereby forming a recess that reduces or changes the size of the receiving surface. Therefore, a substrate (product substrate) with both sides structured or processed can also be used.

[0152] In additional embodiments, the receiving device is configured so that the substrate and / or structured stamp can be heat-treated over the entire area or partially. The receiving device can be heat-treated in a temperature range of -100°C to 500°C, preferably -50°C to 450°C, more preferably -25°C to 400°C, and most preferably 0°C to 350°C.

[0153] An embodiment of a substrate receiving device according to the present invention also enables the handling of a substrate having a liquid layer thereon. The liquid layer is a liquid embossing lacquer or embossing material located at the interface, particularly during contact.

[0154] The embossing material is applied, in particular, by coating over the entire area or by droplets at a defined distance from the substrate or structured stamp. The embossing material is preferably applied on the substrate. Depending on the topography of the substrate and / or structured stamp, the area may be defined with more embossing material or more droplets. The application of the embossing material may be performed using a metering device having a nozzle that can be positioned specifically between the structured stamp and the substrate.

[0155] In another embodiment, the method may be used in combination with an established industrial coating process, such as a spin-coating process. The coating may be performed separately from the embossing process in a separate module. Thus, the coating of the substrate can be fast, defect-free, particle-free, and standardized across the entire area. In particular, this entails throughput advantages.

[0156] In another embodiment, the receiving device preferably includes a device for bending a structured stamp and / or substrate, which is fixed particularly partially, at the center. The device for bending is referred to as a curve element. The curve element is a nozzle through which a fluid, preferably a gas, can escape to create overpressure, particularly between the structured stamp and the receiving device that bends the structured stamp. Curvature of the structured stamp occurs due to the fact that the structured stamp is preferably fixed by vacuum to the receiving device at the circumference. Effects of the invention

[0157] According to the present invention, embossing is initiated after contact with the embossing material, preferably over the entire area of ​​the contact surface of the substrate and the structured stamp, and thus after capillary forces are initiated, particularly due to the separation of the substrate.

[0158] Further advantages, features, and details of the present invention are revealed from the following description of preferred examples of embodiments with the help of the drawings. Brief explanation of the drawing

[0159] FIG. 1a: Cross-sectional view of the apparatus in the first embodiment of the method; FIG. 1b: Cross-sectional view of the apparatus in the first embodiment of the method after the structured stamp and substrate holder have approached the end point without external contact pressure; FIG. 1c: Cross-sectional view of the apparatus in the first embodiment of the method, where the substrate is separated from the substrate receiving apparatus by interruption of vacuum in the vacuum track and is attached conformally to the structured stamp due to capillary force. FIG. 1d: Cross-sectional view of the structured stamp receiving apparatus in the first embodiment of the method after embossing or manufacturing, where the curable embossing material is cross-linked or cured in the stack through the transparent structured stamp, particularly by ultraviolet light. FIG. 1e: Cross-sectional view of the apparatus after embossing, where removal of the substrate from the structured stamp and molding position occurs after the new fixation of the embossed substrate on the substrate receiving apparatus. FIG. 2: Cross-sectional view of the apparatus in the first embodiment of the method with an enlarged cross-sectional view; FIG. 3a: Second cross-sectional view of the apparatus in the first embodiment of the method, where the substrate is separated from the substrate receiving apparatus by interruption of vacuum in the vacuum track and It is attached to a structured stamp in a conformal manner by capillary force. FIG. 3b is a cross-sectional view of the device after embossing, wherein the structured stamp and the substrate are removed from the molding position after the embossed substrate is newly fixed to the substrate receiving device. FIG. 4a: Cross-sectional view of the device in a second embodiment of the method according to the present invention. FIG. 4b: Cross-sectional view of the device in a second embodiment of the method after embossing and curing. FIG. 4c: Cross-sectional view of the device in a second embodiment of the method after being removed from the molding position. FIG. 4d: Cross-sectional view of the device in a second embodiment of the method during the second iteration step of the step-by-step repetitive embossing process. Specific details for implementing the invention

[0160] Identical components or components with the same function are indicated by the same reference number in the drawing. Figures are not scaled to improve representation.

[0161] FIG. 1a illustrates a cross-sectional view of the device in a first embodiment. FIG. 1a particularly illustrates receiving devices (5 and 6) of the device for receiving a structured stamp (2) and a substrate (1). The receiving surfaces of the receiving devices (5 and 6) are particularly fitted to the dimensions and perimeter contours of the structured stamp (2) and the substrate (1).

[0162] In a preferred embodiment, the structured stamp (2) of FIGS. 1a through 1e is an elastomer soft stamp (2). The elastomer structured stamp (2) enables conformal and uniform contact over a large surface. To ensure good separation between the structured stamp (2) and the substrate (1), the stamp surface has the lowest possible surface energy.

[0163] The elastomer structure stamp (2) is supported by a carrier or a stamp carrier substrate (4) if necessary. In other embodiments, glass carrier substrates of different thicknesses are used. As a result of using the stamp carrier substrate (4), the elastomer structure stamp (2) loses at least partially its flexibility. Meanwhile, the flexibility of the structured stamp (2) can be controlled by the choice of the carrier (4). In an alternative embodiment, the carrier (4) may be a plate. In a third embodiment, the carrier (4) is not required. The structure of the structured stamp (2) is not limited to the embodiments of FIGS. 1a through 1e.

[0164] The structure (3, 3') of the structured stamp (2) has dimensions in the range of micrometers and / or nanometers. In a preferred embodiment, fixation of the structured stamp (2) is achieved by low pressure or vacuum through vacuum tracks (8) of a vacuum device (not shown). In the example of the embodiment according to FIGS. 1a through 1e, the negative pressure for fixing the structured stamp is applied as a plurality of vacuum tracks (8) that extend concentrically from one another and cover the receiving surface of a stamp receiving device (5) for receiving the structured stamp. In an alternative embodiment, the vacuum tracks (8) are located only in the side edge regions of the receiving surface of the stamp receiving device (5). In the alternative embodiment, only the outer circular section of the receiving surface of the stamp receiving device (5) is provided to fix the structured stamp (2) by the vacuum tracks (8).

[0165] In a preferred embodiment according to FIGS. 1a to 1e, the substrate (1) is very thin compared to a substrate of the prior art, so flexibility is provided. In this first embodiment, a carrier substrate is not used to stabilize the substrate (1) or the product substrate. The thin substrate (1) is fixed to a receiving device (6) and is easy to handle. In an alternative embodiment, a carrier (not shown) is used to stabilize the thin substrate (1). The carrier may be, for example, a carrier substrate, a carrier plate, or a carrier film. The carrier supports the substrate and prevents bending, but is also thin itself and has sufficient flexibility. Thus, the substrate to be embossed is flexible.

[0166] In a preferred embodiment, the substrate of FIGS. 1a to 1e is a very thin substrate. The thickness of the substrate (1) is particularly 1 μm to 2000 μm, preferably 10 μm to 750 μm, more preferably 100 μm to 500 μm.

[0167] The thickness of the structured stamp (2), substrate (1), and embossing material (7) is not shown in the drawing at the actual scale to improve the representation.

[0168] The receiving surface of the substrate receiving device (6) of FIG. 1a is preferably at least mostly aligned with the dimensions of the substrate (1). In a preferred embodiment, the fixation of the substrate (1) is achieved by low pressure or vacuum through a vacuum track (9) of a vacuum device (not shown).

[0169] In the examples of embodiments according to FIGS. 1a to 1e, the negative pressure for fixing the substrate (1) is applied as a plurality of vacuum tracks (9) that extend concentrically relative to each other and cover the receiving surface of the substrate receiving device (6) for receiving the substrate (1). The fixing means is also configured as individually controllable fixing elements that are particularly uniformly distributed on the receiving surface and divided into zones. In FIGS. 1a and 1b, only the vacuum tracks (9) in the side edge zones of the receiving surface of the substrate receiving device (6) are first individually controlled and activated (control or activation is indicated by arrows). The edge zones extend particularly to half the radius of the receiving surface, preferably up to 1 / 4 of the radius.

[0170] The substrate according to FIG. 1a is already coated over the entire area with an embossing material (7). In a preferred embodiment, the method is used in combination with an established industrial coating process, such as a spin coating process, for example. The application of the layer occurs particularly in spin, spray, or inkjet processes, as well as in immersion coating or roll coating processes. The coating can be performed separately from the embossing process in a separate module.

[0171] In an alternative embodiment according to FIG. 2, the application of the embossing material (7') may be performed by a metering device (13) having a nozzle (12) that can be arranged between the structured stamp (2) and the substrate (1). In the above embodiment, the embossing material (7') is applied as a droplet at a defined distance from the substrate (1). The volume of the droplet is precisely measured and controlled to adjust the thickness of the intermediate layer that remains between the structural recess of the embossing structure and the substrate surface. An intermediate layer thickness as thin as possible is preferred. Preferably, the intermediate layer thickness is 50 μm to 0.01 nm, more preferably 10 μm to 0.01 nm, and most preferably 1 μm to 0.01 nm.

[0172] In one embodiment, the substrate receiving device (6) also enables handling of a substrate (1) having a liquid layer thereon. The liquid layer is, in particular, a liquid embossing lacquer or embossing material (7, 7') and is located at the interface during contact.

[0173] FIG. 1b shows the apparatus for an additional process step. After alignment, the contact surfaces of the substrate (1) and the structured stamp (2) become closer to each other and contact is made over the entire area.

[0174] In an embodiment according to the present invention, a relative movement of approach occurs between the structured stamp (2) and the substrate (1, 1'). Preferably, only one of the receiving devices (5, 6) is moved. Preferably, only the structured stamp (2) is advanced relative to the static substrate receiving device (6).

[0175] In the step of bringing the structured stamp (2) and the substrate (1) into contact according to FIG. 1b, only the fixing means located in the edge region of the substrate receiving device (6) are used. As soon as the structured stamp (2) comes into contact with the substrate (1), the fixation is released from the substrate (1) coated with embossing material (7, 7') by interrupting the vacuum. By reducing the negative pressure at the receiving surface, the detachment of the substrate (1) can be performed in a controlled manner. The fixing element is controlled accordingly. The structured stamp (2) is fixed to the stamp receiving device (5) without alteration.

[0176] After detachment, the substrate (1) continues to adhere to the structured stamp (2) due to the capillary effect or capillary force acting through the embossing material (7, 7') existing between the substrate (1) and the structured stamp (2) according to FIG. 1c, and the embossing process begins over the entire area. According to the present invention, no additional external pressure is required for successful embossing or production. According to the present invention, the receiving devices (5, 6) come closer together only to the extent that the distance H (see FIG. 2) is reduced to a precisely defined distance HE, and the imprint process begins without additional external pressure. The final distance HE is particularly less than 100 µm, preferably less than 10 µm, most preferably less than 500 nm, most preferably less than 100 nm. Due to the effect of the capillary force, the thin and flexible substrate 1 is pulled conformally toward the structured stamp 2. As a result of the flexibility of the substrate (1) and the degree of freedom obtained through the separation of the substrate (1), the substrate (1) is deformed and adjusted to fit the structured stamp (2). Thus, uniform contact is possible during embossing.

[0177] FIG. 1c illustrates a device having a particularly UV-transparent structured stamp (2) loaded onto a stamp receiving device (5), wherein a substrate (1) on the structured stamp (2) with an embossing material (7) placed between them is held together by capillary force. For this to happen, at least the substrate (1) must have high flexibility. Due to the viscosity of the embossing material (7), the intermediate space of the structured stamp (2) is completely filled by the capillary effect.

[0178] In the embodiment according to FIG. 1c, the substrate (1) is no longer placed on the receiving surface of the substrate receiving device (6) after the fixation to the substrate receiving device (6) is stopped and after the influence of the capillary force.

[0179] In a second embodiment (not shown), the substrate (1) is placed on the receiving surface of the substrate receiving device (6) without (active) fixing by a fixing means and without the influence of an external force. Regarding whether contact still exists between the substrate (1) and the receiving surface of the substrate receiving device (6) after the substrate is released by the fixing means (9), this depends, for example, the amount and viscosity of the embossing material (7, 7'), the size of the structure (3, 3') of the structured stamp (2), and the final distance (H E It depends on multiple process parameters (ab), such as the adjustment of ).

[0180] In an alternative embodiment (not shown), a structured stamp (2) is positioned on a lower receiving device and a substrate (1) is positioned on an upper receiving device. After detachment, the substrate (1) continues to adhere to the structured stamp (2) due to capillary forces acting through the embossing material present between the substrate (1) and the structured stamp (2), and is also placed on the embossing material (7) applied as a drop at a defined distance from the structured stamp 2, caused by additional gravity.

[0181] In all embodiments shown, external pressure, particularly contact pressure, is not required to achieve equal or seamless contact between the substrate (1) having the embossing material (7) and the structured stamp (2). The force provided for the transfer of the stamp structure (3) must be applied to the stamp (2) and / or the substrate (1) and consequently used to be perpendicular to the substrate contact surface.

[0182] The above method prevents deformation of the structure (3) of the structured stamp (2) due to contact pressure. Also, the flexibility of the substrate (1) makes it possible to compensate for irregularities of the structured stamp (2) and / or the substrate (1), and also prevents additional embossing defects, such as embossing defects caused by air content resulting from very high quality of the embossing process.

[0183] In the next process step according to FIG. 1d, direct cross-linking of the curable embossing material (7), particularly photoresist or lacquer, occurs by UV light (10). Generally, curing is achieved by electromagnetic radiation, heat, electric current, magnetic field, or other methods. Curing is preferably achieved through a transparent stamp receiving device (5) and a transparent structured stamp (2). Curing of the embossing material (7) by a radiation source within or on the stamp receiving device (5) can also be considered.

[0184] In the final process step according to FIG. 1e, the substrate (1) and the structured stamp (2) are removed from the molding position. Before removal, the substrate (1) is fixed again on the substrate receiving device (6). Fixing of the substrate (1) is achieved by vacuum or low pressure through the vacuum track (9') of a vacuum device (not shown).

[0185] For removal from the molding position, all fixing elements of the substrate receiving device (6), in particular, the fixing elements (9') that are individually controllable and uniformly distributed on the receiving surface, are used and activated (activation is indicated by an arrow).

[0186] FIG. 1e illustrates an embossed and cured embossing material (11) on a substrate (1) after embossing (1i). The method enables high-resolution structuring in the sub-µm range, preferably less than 20 µm, more preferably less than 2 µm, even more preferably less than 200 nm, most preferably less than 10 nm.

[0187] The device preferably includes a group of modules having a common workspace that can be sealed against the ambient atmosphere if necessary. The modules, for example, a coating module, an imprinting module, and an unloading module, may be arranged in a cluster or star shape around a central module containing a moving device (robot system).

[0188] FIG. 3a illustrates an embodiment in which the embossed substrate is deformed due to the effect of capillary force after contact between the substrate (1') and the structured stamp (2) placed between the embossing material (7). The ratio of the individual components and the substrate (1') in FIG. 3a is partially unbalanced, which can be traced particularly to the structure (3) of the structured stamp (2) being displayed in a much more magnified form. Due to the effect of capillary force, the thin and flexible substrate (1') is drawn in a conformal manner toward the structured stamp (2). In the substrate receiving device (6), the substrate (1') can be deformed and adapted to the structured stamp (2). Thus, uniform contact during embossing becomes possible. To this end, at least the substrate (1, 1'), preferably the substrate (1, 1') and the structured stamp (2), must have a high degree of flexibility. As a result of the high degree of flexibility of the substrate (1, 1') and conformal contact, it is desirable that embossing defects be reduced or eliminated.

[0189] Embossing defects that may occur in the prior art of nanoimprint lithography are, among other things, cracks, irregularly filled stamp structures (i.e., air inclusions), and uneven lacquer layer thickness. For example, adhesion between the embossing material, such as lacquer, and the structured stamp is important. For instance, the cured embossing material (11') adheres more strongly to the concave portion of the structured stamp (2), causing the embossed structure to tear while being removed from the molding position.

[0190] Irregularly filled stamp structures (3) result in defects in individual embossing structures in the cured embossing material (11'). The filling of the stamp structures depends, among other things, on factors such as the viscosity of the embossing material (7), the thickness of the coating, or the size and arrangement of the applied embossing material.

[0191] Additional embossing defects are caused by defects in the structured stamp (2) itself, such as a smaller depth of the structure (3) or an uneven surface in some locations, for example. Defects such as an uneven surface of the structured stamp (2), for example, are compensated for by the flexibility of the substrate (1).

[0192] According to the present invention, the stamp (2) of the flexible structure cannot be deformed during the process because no external pressure is applied. The substrate (1, 1') is so thin that stamp defects or defects occurring in the prior art can be compensated for or do not occur. FIG. 3b shows the embossed and cured embossing material (11') on the substrate (1i) after being removed from the molding position.

[0193] The proposed invention can be used particularly in the production of the following products:

[0194] - 1D, 2D, and / or 3D diffractive optical elements (DOE),

[0195] - Microfluidic components,

[0196] - Lenses and lens systems,

[0197] - Fresnel lens,

[0198] - Biomedical elements,

[0199] - Polarizer

[0200] - Nanostructured electrode,

[0201] - IR wave conductor,

[0202] - Angle optics for virtual reality applications,

[0203] - Fiber optic connection,

[0204] - Work stamp for imprint lithography

[0205] - etc.

[0206] FIGS. 4a through 4d illustrate another embodiment of a stepwise iterative process. A structured stamp (2') smaller than the substrate (1'') to be embossed is used. According to FIGS. 4a through 4d, the process is repeated as often or multiple times as necessary to emboss the entire substrate (1'') with the embossing material (7''). The equipment according to the present invention may preferably be installed in a process chamber that is sealed off from the surroundings. Thus, the process chamber can be exhausted and / or ventilated with any gas or mixture of gases.

[0207] FIG. 4a illustrates a substrate (1'') having a layer of embossing material (7'') over the entire area. In another embodiment, droplets of embossing material may be applied to the substrate (1'') at a defined distance. The step-by-step repeating structure stamp (2') is smaller than the substrate (1''). FIG. 4a specifically illustrates a cross-sectional view of a receiving device (5') of a device for receiving the structured stamp (2'). The structure (3') of the structured stamp (2') has dimensions in the range of micrometers and / or nanometers. Fixing of the structured stamp (2') on the stamp receiving device (5') in a preferred embodiment is achieved by low pressure or vacuum through a vacuum track of a vacuum device (not shown).

[0208] In an advantageous embodiment of the present invention, the apparatus is provided to include a curing means for curing an embossed substrate (1''), particularly section by section, preferably a section corresponding to a step-repetition process, particularly a section corresponding to a stamp area of ​​a structured stamp.

[0209] A step-repetition device is considered to be a further development of the device described in patent specification EP2287666A1. In EP2287666A1, a step-repetition device for embossing a substrate in a plurality of embossing steps within an embossing process and additional devices included in the device, in particular a adjusting device, are described.

[0210] In the process step according to FIG. 4b, the embossing material (7'') is structured by a structured stamp (2') that is repeated stepwise. The structured stamp (2') is moved to a first position to emboss at this first position. Preferably, only the structured stamp (2') is brought closer to the static carrier substrate. After contact, direct cross-linking of the curable embossing material (7''), in particular photoresist or lacquer, occurs by UV light (10). Generally, curing is achieved by electromagnetic radiation, heat, electric current, magnetic field, or other methods. Curing preferably occurs through a transparent stamp receiving device (5') and a transparent structured stamp (2'). Curing of the embossing material (7'') by a radiation source within or on the stamp receiving device (5') can also be conceived according to the present invention.

[0211] After being removed from the molding position according to Fig. 4c, a defined section of the substrate (1'') is embossed with a hardened embossing material (11').

[0212] In an additional process step of the step-by-step iterative process according to FIG. 4d, the step-by-step iterative structured stamp (2') moves from a first position to a second predefined position different from the first position.

[0213] Position and emboss again. After contact, direct cross-linking of the embossed curable embossing material (7'') occurs by UV light (10). According to the present invention, multiple curing can also be conceived, wherein the first curing occurs locally after each individual embossing step, and when the step-repetition process is completed, additional curing of the entire substrate (1'') occurs, for example, in a separate module.

[0214] The process according to FIGS. 4a through 4d may continue until a desired area of ​​the substrate (1'') is embossed. In this embodiment, the structured stamp (2') enables embossing without the effect of external force after contacting the embossing material (7'') on the substrate (1''). The structured stamp has means for moving particularly parallel to the surface of the substrate and a lifting system (not shown) for approaching along the Z-direction and removing from the forming position. The high precision of the positioning table of the step-by-step repeating device enables smooth embossing with the structured stamp (2') over the entire circumference of the substrate (1''). Alignment with a previously embossed structure, particularly at the edge of a previously embossed structure section, is possible according to the present invention. The use of a continuous substrate can be conceived in the step-by-step repeating process. A continuous substrate is a substrate stored on a first roll, in particular, whose length is several times longer than its width. In particular, the continuous substrate is a film.

[0215] A lens array, for example, a micro and / or nano lens array, is created by embossing performed side by side with a repetitive or structured stamp (2').

[0216] According to the present invention, no additional external pressure is required for successful embossing. According to the present invention, the stamp receiving device (5') approaches a predefined position only toward the substrate (1'') where the distance H is reduced to a precisely defined final distance H'E. The imprint process begins without any additional additions. External pressure is applied. The final position H'E is particularly less than 100 µm, preferably less than 10 µm, most preferably less than 500 nm, and most preferably less than 100 nm. Through the effect of capillary force, a thin and flexible substrate (1'') is attracted equiangularly toward the structured stamp (2'). Due to the flexibility of the substrate (1''), the substrate (1'') can be deformed and adapted to fit the structured stamp (2'). Thus, uniform contact is possible during embossing. Explanation of the symbols

[0217] 1, 1', 1'': Substrate, Product Substrate 1i: Substrate after embossing 2, 2': Structure stamp 3, 3' : Embossing structure 4: Stamp carrier substrate or backplate for stabilization 5, 5': Stamp receiving device 6: Substrate receiving device 7, 7', 7'': Embossing material 8, 8': Vacuum track of stamp receiving device 9, 9': Vacuum track of substrate receiving device 10: Radiation source 11, 11': Embossing and hardened embossing materials 12: Nozzle 13: Weighing device H: Distance H E , H' E : Final distance

Claims

Claim 1 A method for manufacturing a micro or nano structure comprises: a) fixing a substrate (1, 1', 1'') having an embossing material (7, 7', 7'') applied thereon onto a substrate receiving device (6); b) structuring the embossing material by bringing a structured stamp (2, 2') into contact with the embossing material (7, 7', 7''); c) partially releasing the fixation of the substrate (1, 1', 1'') onto the substrate receiving device (6); d) curing the embossing material while the structured stamp is in contact with the embossing material (7, 7', 7'') after the fixation of the substrate is partially released; and f) removing the cured embossing material (7, 7', 7'') from the structured stamp (2, 2'), wherein the substrate is flexible and configured to be partially shape-coupled with the structured stamp after the fixation is partially released, and after the fixation is partially released, the substrate receiving device A method characterized by moving the substrate relative to the substrate, moving it relative to the stamp receiving device, or partially separating the substrate from the substrate receiving device using capillary force, wherein the embossing material is structured by capillary force without pressure or contact pressure, wherein the substrate receiving device is provided with one or more controllable fixing elements, wherein the substrate and the embossing material are fixed and released through the fixing elements, and wherein the fixing and partial release of the substrate are performed through the control of the controllable fixing elements, so that the separation of the substrate after the structuring of the embossing material or contact between the stamp and the embossing material occurs at a specific point in time. Claim 2 A method according to claim 1, characterized in that the substrate (1, 1', 1'') is flexible and thus can be partially equilateral with the structured stamp (2, 2') after partially releasing the fixation. Claim 3 A method according to claim 1, characterized in that, after partially releasing the fixation of the substrate, partial separation of the substrate (1, 1', 1'') from the substrate receiving device (6) occurs due to relative movement between the substrate receiving device (6) and the substrate (1, 1', 1''), relative movement between the substrate receiving device (6) and the stamp receiving device (5, 5'), or capillary force. Claim 4 A method according to claim 1, characterized in that the embossing material (7, 7', 7'') is structured by capillary force without pressure or contact pressure. Claim 5 A method according to claim 1, wherein a substrate (1, 1', 1'') having an embossing material (7, 7', 7'') is fixed by one or more controllable fixing elements (9, 9') arranged in a substrate receiving device (6), by vacuum or negative pressure, and said fixation is released by one or more controllable fixing elements (9, 9'), or by turning off the negative pressure or generating overpressure. Claim 6 A method according to claim 1, wherein the fixing of the substrate (1, 1', 1'') and the partial release of the fixing of the substrate (1, 1', 1'') are controlled by controlling one or more controllable fixing elements (9, 9') so that the release or separation of the substrate (1, 1', 1'') and the embossing material (7, 7', 7'') occur at a specific time after contact with the structuring of the embossing material (7, 7', 7''). Claim 7 A method according to claim 1, characterized in that, after partial release of fixation, the embossing material (7, 7', 7'') or substrate (1, 1', 1'') conformally fits to the structured stamp (2, 2') without external pressure by capillary force. Claim 8 A method according to claim 1, characterized in that the substrate (1, 1', 1'') is held by the embossing material (7, 7', 7'') by capillary force after contact or after partial release of fixation. Claim 9 A method according to claim 1, characterized in that micro or nano structures are formed side by side in a plurality of layers or next to each other in a step-by-step iterative process. Claim 10 A method according to claim 1, characterized in that the thickness of the substrate (1, 1', 1'') is between 1㎛ and 2000㎛, 10㎛ and 750㎛, or 100㎛ and 500㎛. Claim 11 A method according to claim 1, characterized in that the viscosity of the embossing material (7, 7', 7'') is less than 100,000 cP, less than 10,000 cP, less than 1,000 cP, or less than 500 cP. Claim 12 A method according to claim 1, characterized in that the structured stamp (2, 2') includes an embossing structure (3, 3') or is coated with an embossing structure (3, 3'). Claim 13 An apparatus for manufacturing a micro or nano structure by a method according to any one of claims 1 to 12, wherein: - a substrate (1, 1', 1'') having an embossing material (7, 7', 7'') can be fixed on a substrate receiving device (6); - a structured stamp (2, 2') can be in contact with the embossing material (7, 7', 7''); and - the fixation of the substrate (1, 1', 1'') can be partially released; - the embossing material (7, 7', 7'') can be cured; and - the embossing material (7, 7', 7'') can be removed from the structured stamp (2, 2'). Claim 14 In claim 13, the apparatus comprises: ● one or more sensors for measuring pressure, distance or temperature or, or ● one or more actuators for adjusting a stamp receiving device (5, 5') or a substrate receiving device (6) or ● a control unit, wherein the control unit controls one or more fixed elements (9, 9') or one or more actuators according to a value measured by one or more sensors, and the relative movement, creation, or reduction of a structured stamp (2, 2') with respect to a substrate (1, 1', 1'') having an embossing material (7, 7', 7'') and the gap between the structured stamp (2, 2') and the substrate (1, 1', 1'') can be performed in such a manner that contact can be performed without pressure. Claim 15 delete

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