Device for producing micro- and / or nanostructures

Abstract

This invention discloses a method and apparatus for manufacturing microstructures and / or nanostructures.

Description

Technical Field

[0001] This invention relates to an apparatus and method for manufacturing microstructures and / or nanostructures. Prior Technology

[0002] In prior art, photolithography and / or imprinting were used to fabricate microstructures and / or nanostructures. In recent years, imprinting has been widely adopted. Using imprinting, micron- and / or nano-sized structures can be imprinted onto a material using a mold. The material is an imprinted material applied to a substrate.

[0003] In recent years, such embossing processes have become increasingly important because they can be implemented faster, more efficiently, and at a lower cost than many photolithography processes.

[0004] After depositing the imprinting material, a structured mold is aligned with the substrate. Then, the structured mold and the substrate are brought close together. The structure of the imprinting material is formed within the imprinting material. The imprinting material is cured before being removed from the imprinting material. Curing is performed by heating and / or by electromagnetic radiation.

[0005] In addition to modified or extended masking aligners, there are also separation molding devices designed for and used in specific embodiments. Most of these devices are high-precision alignment systems capable of aligning a mold with a substrate with greater accuracy. Furthermore, these devices can generate a vacuum, have specialized application systems, and the like.

[0006] Imprint lithography works using either hard or soft molds. In imprint lithography, soft molds are primarily used and have always been the preferred choice. This is due to the ease of mold fabrication, the efficiency of the imprinting process, the excellent surface properties of the respective mold materials, low manufacturing costs, the reproducibility of the imprinted products, and especially the elastic deformation of the mold during imprinting and removal from the molded position. A mold made of a polymer (specifically, an elastomer with a microstructured or nanostructured surface) is used in soft lithography to create structures ranging from smaller than nm to >1000 µm.

[0007] Elastomer molds are manufactured as a female mold of a master mold. The master mold is a rigid mold made of metal, plastic, and / or ceramic, manufactured in a single step using costly processes. Any number of elastomeric molds can then be manufactured from the master mold. The elastic modulus of quartz is approximately 100 GPa. In comparison, the elastic modulus of polymers (hard and soft polymers) is several orders of magnitude smaller; therefore, the latter are referred to as "soft" (soft lithography) compared to quartz. Elastomer molds achieve conformal and uniform contact on a large surface. They are relatively easy to separate from their master mold and the imprinted product. To ensure good separation of the mold from the substrate, the mold surface has the lowest possible surface energy. For example, an anti-adhesion coating is often necessary or advantageous.

[0008] To perform soft lithography, an elastomer mold can be supported by a carrier. For example, glass substrates of varying thicknesses are currently used. When using a thick glass substrate, the elastomer mold at least partially loses its flexibility. On the other hand, the flexibility of the mold can be controlled by selecting the carrier. After the imprinting process, using a rigid carrier generally makes it difficult to separate the mold from the substrate.

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

[0010] In nano-imprint lithography, the imprint material can be cured by heating or by UV radiation. In both cases, a structured imprint is pressed into the imprint material. To achieve high-resolution surface structuring, the structured imprint and the substrate are pressed together by pressure. In the case of UV-NIL, lower contact pressures than thermal NIL can be used, and the process can be performed at room temperature. The most important parameters in the NIL process are temperature (especially in the case of thermal NIL), indentation pressure, and the adhesion between the imprint material and the structured imprint.

[0011] Soft and slightly harder molds (specifically, elastomeric molds) can be deformed by applying pressure during nanoimprinting processes. This deformation is pressure-dependent. Such deformation is expected to have a greater impact on smaller structures and is more pronounced with softer mold materials. Deformation or distortion of microstructures and nanostructures caused by contact pressure is found in the cured imprinting material on the imprinting substrate, thus reducing the quality and reproducibility of the imprinting process.

[0012] If the structured mold and / or substrate is too rigid, an external pressure (specifically, a contact pressure) is required to achieve conformal or seamless contact between the structured mold with the mold structure and the substrate with the imprinting material. In the prior art, an actuator device is used, which includes a separate controllable or adjustable actuator for acting on the structured mold and / or substrate using a force for transferring the mold structure and resulting in a force orthogonal to the substrate contact surface.

[0013] To be precise, in the case of a large area, it is difficult to distribute pressure evenly across the entire contact surface and compensate for irregularities. Therefore, a non-uniform structure can occur during imprinting.

[0014] Non-uniformity of one of the impression surfaces can also affect the quality of the embossing process. In addition, gas inclusions and associated embossing defects during pressure embossing are known in the prior art.

[0015] Imprint defects that can occur in NIL include, for example, cracks, irregularly filled impression structures (i.e., air inclusions), and uneven paint layer thickness.

[0016] Capillary lithography (CFL), a less common soft lithography process, is based on filling the mold structure using capillary force without external pressure. In Adv. Funct. Mater. ((2002) 12: 405-413), HH Lee, by name, describes CFL in detail. It allows the elastomeric mold to make conformal contact with the substrate. However, to fill the cavities, the imprint material must have a very low viscosity. Therefore, CFL is performed at higher temperatures and / or has a higher solvent content in the imprint material, often requiring a solvent atmosphere. In CFL, almost only pure PDMS is used as an imprint material because PDMS is permeable to solvents and gases. During PDMS imprinting, cavities are filled by capillary force, and solvent from the imprint material diffuses through the PDMS mold and escapes. Epoxy resin SU-8 has been established as an imprint material for CFL. Issues such as the swelling of PDMS in solvent-based processes and the significant expansion in thermal processes mean that CFLs are only implemented on a laboratory scale, and industrial implementation using molding equipment is unknown. Furthermore, the imprinted material is typically thermally crosslinked in CFLs.

[0017] For example, US 7,442,336 B2 details an apparatus and method for imprinting a substrate using an imprinting material, wherein the substrate and the mold are slowly brought together to a defined distance, such that the intermediate space is filled with the imprinting material due to capillary forces. The external force is kept as small as possible, depending on the properties of the imprinting material, the thickness of the layer to be imprinted, and the size of the substrate surface.

[0018] In US 8,871,048 B2, a flexible elastomer impression is used so that external pressure can be kept as low as possible.

[0019] Capillary microforming (MIMIC) also utilizes capillary forces to create structures with PDMS molds. However, in MIMIC, a PDMS mold with a textured structure is pressed onto a substrate. Thus, a three-dimensional structured hollow space is created between the mold and the substrate. A monomer solution is applied to the front surface of the mold, which then spontaneously fills the capillaries. After curing, the mold can be removed from the substrate. The three-dimensional structure of the polymer remains on the substrate.

[0020] In prior art, the elastic properties of flexible embossing resulted in particularly problematic deformation or distortion of microstructures and nanostructures. Deformation and distortion of microstructures and nanostructures caused by contact pressure were found in the cured embossing material on the embossing substrate, thus reducing the quality and reproducibility of the embossing process.

[0021] Soft embossing molds can deform due to applied pressure during nano-imprinting processes. Specifically, this deformation is pressure-dependent. Furthermore, gas inclusions and associated imprinting defects during pressure imprinting are known in the prior art.

[0022] If the structured mold and / or substrate are too rigid, an external pressure (i.e., contact pressure) is required to achieve a conformal, seamless contact between the structured mold and the substrate with the imprinting material. This can result in pressure-dependent deformation, which reduces the quality of the imprinting process.

[0023] Therefore, the problem of the present invention is to provide a detailed description of an apparatus and method and a substrate that at least partially eliminates (in particular, completely eliminates) the disadvantages mentioned in the prior art. Summary of the Invention

[0024] This problem is solved using features of an independent technical solution. Advantageous developments of the invention are given in the appended technical solutions. All combinations of at least two features given in the [Implementation], claims, and / or drawings also fall within the scope of the invention. Values ​​within the stated value range are also considered as limiting values ​​and can be claimed in any combination. As long as features disclosed with respect to the apparatus can also be considered features of the method, the latter should also apply to the method, and vice versa.

[0025] In the following text, structuring and imprinting should be understood as meaning the fabrication of microstructures and / or nanostructures. Specifically, contact pressure should not occur during imprinting.

[0026] This invention describes a method and apparatus for manufacturing micron and / or nanometer-sized structures. The invention is particularly based on the concept of solving the aforementioned manufacturing technical problems by using a very thin (specifically, flexible) substrate and employing capillary forces. After contact between the imprinting material and the structured mold, the substrate is preferably at least partially released from its fixation by at least one controllable fixing element, thus preferably initiating the imprinting process.

[0027] Therefore, the present invention relates particularly to a method and apparatus for making a structured mold and an imprinting material in conformal contact without the use of external pressure or contactless pressure during an imprinting process.

[0028] Therefore, the present invention relates to a method for manufacturing microstructures and / or nanostructures, comprising at least the following steps in sequence: a) Fixing a substrate with imprinting material onto a substrate receiving device. b) Bring a structured mold into contact with an impression material. c) At least partially eliminate the substrate fixing. d) Curing the embossing material, e) Self-structured mold removal of embossing material.

[0029] Furthermore, the present invention relates to an apparatus for manufacturing microstructures and / or nanostructures using the above-described method, wherein a substrate having an imprinting material can be fixed on a substrate receiving device, and wherein a structured mold can contact the imprinting material, and wherein the fixing of the substrate can be at least partially cancelled, and wherein the imprinting material can be cured, and wherein the imprinting material can be removed from the structured mold.

[0030] Furthermore, the present invention relates to an article having a microstructure and / or nanostructure, wherein the microstructure and / or nanostructure is manufactured using a method according to the present invention and using an apparatus according to the present invention.

[0031] In one preferred embodiment of the invention, the substrate is specified to be flexible and thus adaptable to at least partially conformally retain the structure of the mold, specifically after the fixation is removed or during the structuring of the imprinting material. Specifically, the substrate has a small thickness and / or is composed of a portion of flexible material, such that during manufacturing, it can advantageously partially embody the structure of the mold. The substrate may also be unsuitable or fully suitable for the mold. After the imprinting material has cured, the substrate with the cured imprinting material forms a unit. Therefore, the substrate can advantageously assist the imprinting process and prevent imprinting defects. Furthermore, the thin, flexible substrate can deform during the process. Specifically, the substrate can be advantageously attracted and deformed toward the mold in a conformal manner by capillary action. Additionally, better uniform contact during manufacturing is achieved by flexibility. The flexibility of the substrate advantageously enables careful and uniform imprinting without imprinting defects. By eliminating the fixation, an additional degree of freedom is advantageously gained, allowing a thin and flexible substrate (specifically, due to capillary forces) to assist the process in the desired manner. After the fixation is removed, the substrate rests freely on the substrate receiving device. Due to the attraction of the imprinting material and the substrate toward the structured mold, it is conceivable that the substrate may be partially or completely peeled off from the substrate receiving device, particularly by capillary forces. Specifically, due to the flexibility of the substrate, no external pressure is required to transfer the structure to the imprinting material. Therefore, specifically, the substrate can compensate for irregularities, further improving the quality of the imprinting process.

[0032] In another advantageous embodiment of the invention, it is specified that after at least partially removing the substrate from the substrate receiving device, the substrate is at least partially detached from the substrate receiving device, specifically by relative movement between the substrate receiving device and the substrate and / or by relative movement between the substrate receiving device and a mold receiving device and / or by capillary force. Specifically, detachment may result in a gap between the substrate and the substrate receiving device. However, it is also conceivable that removing the fixation may not result in detachment of the substrate or the creation of a gap. Furthermore, a gap between the substrate and the substrate receiving device may be created, particularly by an actuator, after at least partial removal of the fixation. The gap created by the actuator is then advantageously adapted to the process, specifically, to the material properties. Particularly due to surface tension and capillary force, the substrate continues to adhere to the imprinting material or be attracted toward the structured mold, thus advantageously creating a degree of freedom for the substrate. Corresponding to the configuration of the substrate receiving device relative to the mold receiving device, a further force (specifically, gravity) may be applied during the imprinting process. Specifically, a gap may be partially created during contact, specifically by an attraction applied to the substrate due to capillary forces acting on the imprinting material. However, preferably, the gap is not created until at least partially released from fixation. Due to the gap, the reproducibility and efficiency of the imprinting process (specifically, multiple imprinting steps performed simultaneously and / or in parallel) can be advantageously improved. Furthermore, the substrate can be deformed and, due to the gained degrees of freedom, is suitable for structured molds. Specifically, imprinting defects can therefore be prevented.

[0033] In another advantageous embodiment of the invention, the structured impression is specified as either a hard impression or a soft impression. Specifically, the structured impression may include a soft or hard embossing structure. Specifically, a hard impression should be understood to mean a master impression. Therefore, soft impressions and microstructures and / or nanostructures can be manufactured efficiently and cost-effectively using processes (specifically, by selecting suitable process parameters and techniques suitable for manufacturing materials). Furthermore, by appropriately selecting the structured impression, deformation of the structured impression (specifically, the embossing structure of the structured impression) can be prevented, and uniform and reproducible embossing can be achieved.

[0034] In another advantageous embodiment of the invention, the embossing material is structured without pressure and / or without contact pressure (specifically, by capillary force). Therefore, deformation of the structured mold can be advantageously reduced (specifically, prevented). Furthermore, the reproducibility of the embossing process is increased and embossing defects can be prevented. Additionally, the method is more efficient and cost-effective. Advantageously manufacturing the structure without external pressure can advantageously improve the material properties of the embossing material after curing, such as (e.g.) strength or surface properties. Additionally, the substrate can be advantageously held after removal. The advantages of the method also apply to the fabrication of microstructures and / or nanostructures, as the smaller the structure, the stronger the capillary action. Therefore, embossing can be performed without mechanical pressure, wherein the embossing material is advantageously received by the structure and is thus particularly suitable for structures. Advantageously, when the embossing material and the structured mold come into contact, only touching or wetting of the structured mold (specifically, an embossed structure surface) is required.

[0035] In another advantageous embodiment of the invention, a substrate having imprinted material is specified to be fixed to a substrate receiving device by a controllable fixing element (specifically, by vacuum and / or negative pressure) disposed in the substrate receiving device, and / or the fixing is canceled by at least one controllable fixing element (specifically, by cutting off the negative pressure and / or by generating an overpressure). At least one fixing element can advantageously fix the substrate to the substrate receiving device, specifically, at a specific point. Specifically, the fixing element can be a vacuum track arbitrarily disposed or set in the surface of the substrate receiving device, specifically, in a circular or spiral shape. The fixing element can preferably generate an overpressure and / or negative pressure. Specifically, the force generated therefrom can be arbitrarily introduced onto the substrate (specifically, on the side of the substrate facing the substrate receiving device). Specifically, this can thus produce, for example, a curvature of the substrate. The substrate is fixed to, for example, the edge of the substrate receiving device by a negative pressure and an overpressure is generated by other fixing elements, wherein the substrate is advantageously lifted, particularly at the center. In this manner, the contact point can be adjusted, particularly during contact. Furthermore, at least one retaining element can advantageously prevent imprinting defects (specifically, gas inclusions) by partially securing or desecured in a technically advantageous and controlled manner. During desecured phase, the retaining element can also release the substrate individually and / or in groups according to a specific sequence. Therefore, the fabrication of the structure can be advantageously initiated (specifically, initiated in a specific area). The retaining element is preferably constructed such that the substrate with cured imprinting material can be removed from the structured mold by the retaining element. An imprinting process can be advantageously initiated by the retaining element. During the release or loosening of the substrate, capillary forces can advantageously act on the imprinting material and / or the substrate. The retaining element particularly enables careful and uniform fabrication of the substrate. Additionally, substrate removal can also be carried out in a particularly careful and advantageous manner. The substrate receiving device and the substrate preferably have a wafer shape.

[0036] In another advantageous embodiment of the invention, the fixing of the substrate and at least partial cancellation of the fixing of the substrate are specified to be controlled (specifically, by controlling at least one controllable fixing element), such that the structured imprint material and / or release or removal of the substrate occurs at a specific time after the structured mold is brought into contact with the imprint material. The at least one fixing element is preferably controlled by a control unit and thus advantageously influences the timing of the cancellation of the substrate fixing and thus the timing or release of the substrate. Specifically, the cancellation of fixing may be specified to begin at different points from a plurality of controllable fixing elements. Specifically, the timing and location of the cancellation of fixing can therefore be advantageously controlled. The control unit preferably controls the at least one fixing element based on a value (specifically, a value provided by a sensor).

[0037] In another advantageous embodiment of the invention, the structured mold is constructed such that, after at least partial removal of fixation, the imprinting material and / or substrate are conformally adapted or attracted toward the structured mold (specifically, by capillary force) without external pressure in a conformal manner. The structured mold (specifically, the imprinting structure of the structured mold) is constructed such that the structure is advantageously transferred to the imprinting material (specifically, by capillary force). Specifically, the contact surfaces of the structured mold (which contact the imprinting material during contact) are constructed such that they can make uniform contact, particularly over the entire area. Advantageously, the structure or recesses and / or protrusions of the imprinting structure of the structured mold are configured such that structuring can be performed without pressure. Specifically, the imprinting structure to be transferred is constructed such that, after removal of fixation, the substrate is conformally adapted to the structure. Advantageously, the structured mold is also designed for easy removal. Specifically, the structured mold or imprinting structure is reusable. Therefore, the process can be carried out continuously, efficiently, and repeatedly by using the same structured mold.

[0038] In another advantageous embodiment of the invention, it is specified that after contact and / or after at least partial unfixation, the substrate is held by an imprinting material (specifically, by capillary force and / or surface tension). Thus, after unfixation, the substrate is at least partially adhered to the imprinting material on the structured mold. Specifically, the substrate can be detached from the substrate receiving device due to the capillary force acting on the imprinting material. The substrate remains held due to the release of the substrate or due to unfixation, wherein the substrate can advantageously be adapted to the structured mold. Specifically, the substrate can advantageously be adapted freely and uniformly to the imprinting structure. Furthermore, irregularities can thus be compensated for. Specifically, any present gas inclusions can escape. Advantageously, the quality of the imprinting process is thus improved.

[0039] In another advantageous embodiment of the invention, microstructures and / or nanostructures are fabricated as multiple layers on top of each other and / or side-by-side in a step-by-step repeating process. Specifically, a multilayer construction is repeated until the minimum flexibility required for the substrate is no longer present. Therefore, the process can be carried out more efficiently and cost-effectively. Furthermore, different layers can be fabricated on top of each other. Additionally, multiple functional structures can be fabricated on a large area or side-by-side in a constant imprinting process. Therefore, the method can be used to efficiently manufacture the most diverse products (specifically, structured films). Specifically, the structured mold can be advantageously reused because the resistance of the structured mold increases without contact pressure, or the structured mold can be used in multiple imprinting steps.

[0040] In another advantageous embodiment of the invention, the thickness of the substrate is specified to be between 1 µm and 2000 µm, preferably between 10 µm and 750 µm, and more preferably between 100 µm and 500 µm. The flexibility of the substrate can be increased by using a thinner substrate. Therefore, the substrate can still be better suited for imprinted structures and irregularities can be compensated for. Furthermore, more layers can be manufactured one on top of the other, as the required flexibility is provided in more imprinting steps.

[0041] In another advantageous embodiment of the invention, the total viscosity of the imprinting material is specified 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. By using an imprinting material with a low cP value (specifically, for holding the substrate), the effect of capillary forces and the conformal adaptation to the imprinting structure of the substrate and / or the imprinting material can be improved. Furthermore, a low cP value is beneficial for compensating for irregularities. Additionally, the flexibility of the substrate is utilized optimally, thus achieving improved imprinting quality. With a suitable viscosity of the imprinting material, the imprinting behavior of the imprinting material and, in particular, the holding of the substrate can be advantageously adjusted.

[0042] In another advantageous embodiment of the invention, the structured mold is specified to include an imprinting structure and / or an imprinting structure coated thereon. Therefore, the imprinting mold itself may include an imprinting structure or be coated with an imprinting structure, specifically adapted to the imprinting process. Thus, the imprinting behavior can be advantageously adjusted. Specifically, the fabrication of the structure can be individually adjusted for the process by using different imprinting coatings. Different imprinting structures can be transferred using a single imprinting mold, specifically in a step-by-step repetitive process.

[0043] In another advantageous embodiment of the invention, the apparatus for manufacturing microstructures and / or nanostructures is specified to specifically perform the above-described process, wherein a substrate having an imprinting material is fixed to a substrate receiving device, and wherein a structured mold is in contact with the imprinting material, wherein the fixing of the substrate can be at least partially eliminated, wherein the imprinting material can be cured, and wherein the imprinting material can be removed from the structured mold. The apparatus can advantageously manufacture microstructures and / or nanostructures, specifically, without additional pressure. Therefore, the quality of the imprinting process is improved.

[0044] In another advantageous embodiment of the invention, the specified device further includes one or more sensors for measuring pressure, distance, and / or temperature, and / or one or more actuators for adjusting the mold receiving device and / or substrate receiving device, and a control unit, wherein the control unit controls at least one fixed element and / or at least one actuator, specifically, depending on a value measured by at least one sensor, wherein relative movement of the structured mold relative to a substrate having imprinting material (specifically, the creation or reduction of a gap between the structured mold and the substrate) can be carried out in a manner that allows contact to be carried out, particularly without pressure. Specifically, the specified control unit induces contact of one of the structured mold surfaces (specifically, the imprinted structure surface) by triggering the actuator based on the sensor value. Thus, contact can advantageously be carried out without additional contact pressure. The actuator for creating the gap can be configured on or engaged with any component, preferably with the substrate receiving device and / or mold receiving device. Thus, it can advantageously ensure that the fabrication of microstructures and / or nanostructures is carried out in an optimal manner. Furthermore, the control unit is configured in a manner that advantageously enables the substrate to be detached and removed from its self-forming position by the fixing element, specifically depending on the sensor value. This has the advantage of improved process quality and avoidance of imprinting defects.

[0045] In one non-preferred embodiment of the invention, the control unit of the specified device induces contact with additional contact pressure by triggering an individually controllable actuator. The resultant force for transferring the mold structure orthogonal to the substrate contact surface is <500 N. The structured mold may, for example, be located over the entire area in the form of a wafer, or alternatively, particularly in a step-by-step repetitive process, may have a smaller defined area than the substrate to be imprinted. The resultant pressure for transferring the mold structure orthogonal to the substrate contact surface is particularly less than 50 N / mm², preferably less than 25 N / mm², more preferably less than 10 N / mm², most preferably less than 1 N / mm², and most preferably less than 0.1 N / mm².

[0046] Compared to substrates described in the prior art, the substrate of this invention is very thin. The carrier-free substrate is used to stabilize the substrate (or product substrate), or the carrier substrate, carrier plate, or carrier film itself is thin and flexible. Therefore, the substrate to be imprinted is very flexible, especially with flexible mounting.

[0047] Micro-molding and / or nano-molding processes are performed using a structured mold (preferably an elastomeric structured mold, more preferably a structured mold in wafer form). The structured mold contacts a substrate, preferably pre-coated over the entire area, and particularly contacts the imprinting material provided on the substrate.

[0048] The structured mold and the substrate are each fixed to a receiving device in a molding apparatus. The substrate is preferably fixed to the substrate receiving device using a vacuum or negative pressure. After alignment, the contact surfaces of the substrate and the structured mold are in contact over the entire area. Once the structured mold contacts the substrate, it is released from the substrate coated with the imprinting material, particularly by interrupting the vacuum. Through capillary action, the thin, flexible substrate is attracted towards the structured mold in a conformal manner. Due to the flexibility of the substrate and the degrees of freedom gained by removing the substrate, the substrate can be deformed and adapted to the structured mold. Therefore, uniform contact is achieved during imprinting.

[0049] The substrate and substrate mold are held together by capillary force using an imprinting material between them. For this purpose, at least the substrate (preferably, the substrate and the structured mold) must have a high degree of flexibility. Due to the viscosity of the imprinting material, the intermediate space of the structured mold is also completely filled by the imprinting material due to capillary action.

[0050] Due to the use of capillary forces, no additional external pressure is required during imprinting or fabrication of microstructures and / or nanostructures, and / or there is no contact pressure between the substrate and the structured mold. Therefore, structural deformation of the structured mold caused by contact pressure is avoided (specifically, prevented).

[0051] Specifically, capillary force should be understood as the force caused by surface tension and / or interfacial tension. Capillary ascent and descent can be used, especially during manufacturing. Further forces can also occur during manufacturing, such as adhesive forces and gravity. Due to microstructures and / or nanostructures, the fact that the smaller the structure, the greater the effect of capillary force or capillary pressure can be taken advantage of.

[0052] The flexibility of the substrate can compensate for the irregularities of the structured mold and / or the substrate and also prevent further imprinting defects (such as imprinting defects caused by air inclusions), thus the quality of the imprinting process is very high.

[0053] By utilizing capillary force, no additional external pressure is required during imprinting, and / or there is no contact pressure between the substrate and the mold. Therefore, the apparatus and imprinting process are advantageously simplified, as no actuator device is needed to transfer force.

[0054] Due to the flexibility of the substrate and the degree of freedom gained by removing the substrate after contact without external pressure, the substrate can be deformed and is particularly suitable for structured printing.

[0055] A uniform, conformal contact can be achieved during the imprinting process. Therefore, a very good molding is obtained without the presence of imprinting gaps caused by areas of non-contact or poor contact during imprinting and subsequent curing.

[0056] The proposed invention prevents deformation of the microstructure and / or nanostructure of structured impressions caused by contact pressure.

[0057] The viscosity of the embossing material is preferably between 1 cP and 100,000 cP, which makes it possible to make a wide selection of embossing materials or embossing varnishes and to optimize the process of using the best combination of substrate, mold material and embossing material.

[0058] Specifically, the embossing material does not need to have a low viscosity. Specifically, a solvent atmosphere is not required.

[0059] Contact and imprinting can be carried out under environmental pressure, such as in an air or inert gas atmosphere. Other (specifically, controllable) procedural pressures are also conceivable.

[0060] Specifically, contact and imprinting can be performed at room temperature and high temperature.

[0061] The described method advantageously achieves high output and can particularly reduce the unit cost per manufacturing unit.

[0062] Imprinting of periodic and aperiodic microstructures and nanostructures is feasible.

[0063] Advantageously, precise alignment is not absolutely necessary. The alignment of the substrate and the structured mold before contact (e.g., using a high-precision alignment system only roughly or finely) can vary depending on the situation.

[0064] Different types of flexible substrates can be used in the described method.

[0065] Imprinting or manufacturing can be performed using smooth surfaces and / or rough surfaces. The roughness can be varied depending on the situation.

[0066] Imprinting or manufacturing can be performed, particularly using flat surfaces and / or curved imprint surfaces. Due to the flexibility of the substrate and the migration rate at which the substrate is removed after contact without external pressure, the substrate can be deformed and is suitable for imprinting.

[0067] Both conductive and non-conductive UV-curable embossing materials can be used.

[0068] Both conductive and non-conductive thermosetting embossing materials can be used.

[0069] Using the proposed invention, a multilayer imprinting process can be implemented. A first imprinted and cured layer of a flexible substrate can be coated again with a second imprinting material in a further step, followed by imprinting and curing of the second imprinting material again. Specifically, as long as sufficient substrate flexibility remains, it is conceivable to manufacture further layers. Furthermore, multiple imprinting steps can be performed in parallel and / or side-by-side with each other, and combined with substrates manufactured in the previous cases.

[0070] In the described method, the thickness of the imprinting material on the substrate can be varied as needed, so that both thin and thick imprinting material layers can be imprinted or manufactured.

[0071] Using the proposed invention, two working molds can be manufactured for lithography and can also be used to imprint different types of imprint materials (which can be cured by heating or by electromagnetic radiation (specifically, UV radiation)) onto structured substrates. UV-curable imprint materials are preferred.

[0072] The proposed invention can be used in particular for manufacturing the following products: - 1D, 2D and / or 3D diffractive optical elements (DOE) - Microfluidic components, - Lenses and lens systems - Fresnel lens, - Biomedical components, - Polarizer, - Nanostructured electrodes, - IR waveguide, - Angular optical devices for virtual reality applications - Fiber optic connection, - Working impressions used in embossing microfilming - and others.

[0073] Capillary action is primarily caused by the surface tension of the liquid itself or the interfacial tension between the liquid and the solid surface. Capillary forces occur between the solid surface and the liquid, or between solids in the presence of a very small amount of liquid. The cohesive forces between liquid molecules and the adhesive forces between the liquid molecules and the surfaces of the substrate and the substrate mold (attributed to the presence of a coating of imprinting material between them) contribute to the fact that the two surfaces remain in contact after contact, especially in the absence of external forces. It is advantageous to use a thin, flexible substrate, such that the capillary forces have a corresponding intensifying effect and the substrate is attracted towards the structured mold in a conformal manner.

[0074] A further step in the process: Once the structured mold contacts the substrate, it is detached from the thin-coated substrate. The fixation of the substrate coated with the imprinting material is particularly achieved by releasing the fixation (e.g., by interrupting the vacuum).

[0075] Due to the effect of capillary forces, the thin flexible substrate remains connected to the structured mold in a conformal manner.

[0076] Due to the flexibility of the substrate and the degree of freedom gained by the substrate after detachment from the substrate housing, the substrate can be deformed and is suitable for structured printing. Therefore, uniform contact is achieved during printing.

[0077] Due to conformal contact, the intermediate space of the structured impression is completely filled, especially due to the viscosity of the imprinting material and also due to capillary action. Capillary pressure depends particularly on the size of the structure.

[0078] The smaller the structure, the greater the capillary pressure. High-resolution structuring systems are feasible in the lower nm range (≤50 nm) because the capillary pressure is greatest in this range.

[0079] In addition, it advantageously prevents imprinting defects caused by the use of external contact pressure during the imprinting process. method

[0080] Compared to substrates in prior art, the substrate is very thin. The carrier-free substrate is used to stabilize the substrate (or product substrate), or the carrier substrate, carrier plate, or carrier film itself is thin and flexible. Therefore, the substrate to be imprinted is very flexible.

[0081] Microimaging and / or nanoimprinting processes are performed using a structured mold (preferably an elastomeric mold, specifically in wafer form). The structured mold is brought into contact with a substrate, preferably pre-coated over the entire area.

[0082] Specifically, the structured mold and the substrate are each fixed to a receiving device of a molding apparatus. The substrate is preferably fixed to the substrate receiving device by means of a vacuum or negative pressure. After alignment, the contact surfaces of the substrate and the structured mold are in contact over the entire area. Once the structured mold is in contact with the substrate, the fixing is released, particularly by interrupting the vacuum, from the substrate coated with the imprinting material. The release procedure can be applied over the entire area or along a predefined path. The fixing elements are controlled accordingly.

[0083] If the substrate detaches from the receiving device over the entire area after contact, the substrate continues to adhere to the structured mold due to capillary action (capillary force) through the imprinting material present between the substrate and the structured mold. According to the present invention, no additional external pressure is required for successful imprinting or manufacturing.

[0084] Due to capillary forces, the thin, flexible substrate is attracted toward the printing mold in a conformal manner. Because of the substrate's flexibility and the degrees of freedom gained by removing the substrate, it can deform and adapt to the printing mold. Therefore, uniform contact is achieved during the printing process.

[0085] The substrate and the structured mold are held together by capillary forces using the imprinting material between them. For this purpose, the substrate must possess at least a high degree of flexibility. Specifically, due to the viscosity of the imprinting material, the intermediate space of the structured mold is completely filled by the imprinting material due to capillary action.

[0086] Therefore, the proposed invention prevents structural deformation of the structured mold caused by contact pressure. In addition, the flexibility of the substrate can compensate for the irregularities of the mold and / or the substrate and also prevent further imprinting defects (such as imprinting defects caused by air inclusions), thus resulting in a very high quality imprinting process.

[0087] During the adaptation and deformation of the thin substrate to the structured mold, the gas (specifically, air or inert gas) present between the substrate and the structured mold can be expelled, allowing the imprinting to be performed without gas inclusions. Air or other gas inclusions can be prevented, particularly by regulating the release of one of the holding elements that hold or fix the substrate. Advantageous removal of the substrate can be achieved, particularly by a single release at one of the holding elements (specifically, a concentrated release along one of the wafer surfaces).

[0088] After the imprinting material has cured, a vacuum can be used to fix the substrate back onto the receiving device as needed, allowing for removal of the self-formed position.

[0089] The method according to the present invention for imprinting thin flexible substrates using a structured mold of microstructured and / or nanostructured methods particularly includes the following steps in particular, in sequence: a) Fix the substrate and the structured mold onto the corresponding receiving device; b) Apply the imprinting material to the substrate; c) Rough and / or fine adjustments to the substrate and structured mold; d) The imprinting process is initiated by contacting a substrate with imprinting material with a structured mold, particularly by relative movement of a substrate receiving device and / or a mold receiving device, such that the substrate is attracted toward the structured mold by capillary action and a conformal contact is formed. e) Once contact is made, the flexible substrate is released and secured from the substrate receiving device. Due to the resulting degree of freedom, the flexible substrate is deformable and suitable for structured printing. f) Curing the embossing material; g) Reattach the imprint substrate to the substrate receiving device and remove the structured mold and substrate from the molding position.

[0090] Imprinting preferably begins after the imprinting material comes into contact with the contact surface of the substrate and the structured mold, and therefore after capillary force is applied, especially by removing the substrate.

[0091] After release, the thin substrate is no longer subject to any fixation by the receiving device and can therefore be adapted for structured printing.

[0092] Contact is preferably described as contact over the entire area. Alternatively, contact may occur from the edge or the center. In a further embodiment of the invention, point-to-point contact is achieved by means of a bending member to implement a bent structured mold and / or substrate. Contact may advantageously be assisted, particularly by a controlled fixing element.

[0093] In another embodiment, a step-by-step repetition process is implemented. In this process, a structured mold is used such that a repetitive structure is applied to the circumference of an impression roller. The specified apparatus includes a curing member for curing the impression substrate, and specifically, segments, preferably segments corresponding to the step-by-step repetition process, are used, particularly corresponding to one impression region of the structured mold. Substrate, structured printing mold and imprinting material

[0094] Preferably, the substrate and / or substrate mold is flexible to achieve conformal contact across the entire substrate surface or on one of the structured mold surfaces. In a preferred embodiment, the substrate is very thin, providing advantageous flexibility. A carrier-free substrate is used to stabilize the substrate, or the carrier substrate, carrier plate, or carrier film itself is thin and flexible. Therefore, the substrate to be imprinted is very flexible. The thin substrate is fixed to a receiving device, thereby facilitating processing.

[0095] The substrate can have any shape, preferably circular, rectangular, or square, and more preferably in wafer form. The total diameter of the substrate exceeds 2 inches, preferably 4 inches, more preferably 6 inches, more preferably 8 inches, and most preferably 12 inches. Specifically, a substrate should be understood to mean a wafer.

[0096] The thickness of the substrate is particularly between 1 µm and 2000 µm, more preferably between 10 µm and 750 µm, and even more preferably between 100 µm and 500 µm.

[0097] Structured molds can have any shape, preferably circular, rectangular, or square, and more preferably in wafer form. The diameter of the structured mold is preferably substantially the same as the diameter of the substrate.

[0098] To implement soft lithography, elastomeric structured molds are used as standard, and preferably UV-transmitting polymer molds.

[0099] Transparent elastomer structured molds for UV-NIL are made of, for example, polymers such as polydimethylsiloxane (PDMS), polyorganosilsesquioxane (POSS), perfluoropolyester (PFPE), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), ethylene tetrafluoroethylene, etc. Combinations of multiple materials and multiple layer systems are possible.

[0100] The structured impression is preferably fixed to a backplane (specifically, a plate, preferably a glass substrate). Further conceivable materials for the backplane include polymers and / or metals. Specifically, the backplane can also be an impression carrier substrate.

[0101] On its imprinting side, the structured imprint particularly has a plurality of imprinting structures preferably distributed (specifically, regularly arranged) across the entire imprinting area on the imprinting side. The size of the individual structures of the imprinting imprint is in the range of micrometers and / or nanometers. Specifically, the size of the individual structure is less than 20 µm. Specifically, the size of the individual structure is between 0.1 nm and 20 µm, preferably between 1 nm and 10 µm, more preferably between 1 nm and 5 µm, and even more preferably between 1 nm and 2 µm.

[0102] Structured molds may include a positive and / or negative profile located on the side facing the substrate surface to be processed. Structured molds may also include embossing structures of different dimensions.

[0103] In an alternative embodiment, the structured mold is made of a hard UV-transmitting material such as, for example, glass, quartz, or silicon dioxide. In this embodiment, the substrate must in particular have the required layer thickness and flexibility. In a further embodiment, the structured mold is made of a hard material such as, for example, silicon, a semiconductor material, or a metal such as Ni or Ti.

[0104] Specifically, imprinting materials are cured by chemical and / or physical processes. Specifically, imprinting materials are cured by electromagnetic radiation and / or by temperature.

[0105] Curing is preferably carried out by electromagnetic radiation (especially by UV radiation). In this case, if the imprinting material is cured from the structured mold side, the structured mold better transmits the required electromagnetic radiation.

[0106] A corresponding radiation source is preferably disposed on the side of the structured mold facing away from the imprinting structure. Therefore, the structured mold transmits a wavelength range between 5000 nm and 10 nm, more preferably between 1000 nm and 100 nm, more preferably between 700 nm and 200 nm, and most preferably between 500 nm and 250 nm.

[0107] The optical transparency of the structured impression 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%.

[0108] The viscosity of the embossing material is preferably between 1 cP and 100,000 cP, which makes it feasible to have a wide selection of embossing materials / imprinting varnishes and to optimize the process of using the best combination of substrate, impression material, and embossing material. Specifically, the viscosity is 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.

[0109] Specifically, the imprinting material is applied over the entire area or as droplets at defined intervals onto a substrate or structured mold. The imprinting material is preferably applied onto the substrate. The application of the imprinting material can be performed before or after fixing the substrate. According to the invention, more imprinting material or more droplets can also be used to define the area, depending on the topology of the structured mold or the size of the structure. The application of the imprinting material can be carried out, for example, using a metering device with a nozzle that can be configured between the structured mold and the substrate.

[0110] In another embodiment, the invention can be used in conjunction with existing industrial coating processes such as spin coating. Coating can be performed separately from the imprinting process in a separate module. Therefore, substrate coating is fast, defect-free, full-area, particle-free, and standardized. Specifically, this results in yield advantages and cost reduction. device

[0111] Specifically, the present invention relates to the described method and an apparatus for transferring a structure (specifically, a microstructure or a nanostructure) from a UV-transmittable structured imprint to a flat side of a substrate (specifically, coated over the entire area), wherein a substrate holder accommodates the substrate on a substrate receiving surface and on a structured surface of the structured imprint, which is parallel to and can be configured to face the substrate contact surface.

[0112] The device can be preferably installed in a processing chamber that is hermetically sealed relative to the surrounding environment. Therefore, the processing chamber can be evacuated and / or vented with any gas or gas mixture. The processing chamber can be evacuated to a pressure of less than 1 bar, preferably less than 10 mbar, and more preferably less than 5 mbar.

[0113] In a preferred embodiment, the method according to the invention is carried out under ambient pressure (e.g., in an air or inert gas atmosphere).

[0114] Specifically, the processing chamber can be filled with any gas or gas mixture. This is particularly advantageous when the imprinting is not intended to be performed under a vacuum. One possible, but not the only, reason for forgoing a vacuum is the high volatility of the imprinting material at low ambient pressures. The slight volatility characterized by high vapor pressure can decisively cause contamination of the processing chamber.

[0115] Next, the gas used should interact with the imprinting material as little as possible. Preferably, it should be filled with an inert gas that does not interact with the imprinting material.

[0116] Contact and imprinting can be performed at both room temperature and high temperature. The device according to the invention has components suitable for temperature regulation and heating.

[0117] In another embodiment, the contact between the substrate and the structured mold is particularly critical, as defects can occur here and a reproducible adjustment accuracy cannot be met. The device can be used, for example, by employing the SVA (Smart® View Alignment) method to combine high-precision alignment of different layers above and below each other, adjusted imprinting, etc. In the critical step of aligning the contact surfaces of the substrate and the (nano)structured mold, a more accurate adjustment accuracy or offset of less than 100 µm is desirable, especially less than 10 µm, preferably less than 1 µm, most preferably less than 100 nm, and most preferably less than 10 nm.

[0118] The substrate and the structured mold are aligned together in the described apparatus, such that the approach and adjustment of a micro-molding and / or nano-molding imprinting process are performed in a controlled manner. According to patent specification EP2612109B1, the apparatus preferably includes a non-contact wedge error compensation system for aligning the mold parallel to the substrate, wherein the approach member is used to bring a first surface toward a second surface in a translational direction (T) transverse to the receiving surface of the receiving apparatus until in the final position.

[0119] In another embodiment, a coarse alignment is sufficient. Specifically, an accurate alignment is not required because the thin substrate is suitable for structured printing due to its flexibility and the given mobility of the substrate holder.

[0120] The substrate and structured mold are fixed to a receiving device (chunk). Specifically, the receiving device is determined by a flat receiving surface or holding surface used for holding and fixing. The receiving device for the substrate and structured mold is preferably a vacuum sample holder. It is also conceivable to use an electrostatic sample holder, a sample holder using magnetic or electrical fixation, a sample holder with variable adhesion, or a sample holder suitable for mechanical clamping.

[0121] In a preferred embodiment, the substrate and the structured mold are fixed to a flat, hardened surface on which milled vacuum tracks are located by a negative pressure or vacuum. The substrate receiving device has vacuum tracks on the entire surface or in areas beyond the surface. The negative pressure channels preferably run concentrically (specifically, in a circular shape) to a center Z of one of the receiving devices, specifically around the entire circumference. Thus, a particularly uniform fixation is advantageously achieved.

[0122] The receiving device (specifically, the substrate receiving device) preferably has vacuum tracks only in the area outside the surface, such that the substrate is only partially secured, specifically at the edges. Specifically, there is a possibility of completely releasing the substrate and / or structured mold from the receiving device. For this purpose, the securing of the receiving device is removed (specifically, the vacuum is maintained). A securing element acting with a negative pressure for securing can also be used, as can an overpressure for removing the substrate. According to an advantageous embodiment, the receiving device may include a second vacuum zone to ensure that the substrate is secured to the entire area after the imprinting and curing process.

[0123] If the fixing element is provided as a vacuum element, it can generate a pressure of less than 1 bar, preferably less than 0.1 millibar, more preferably less than 0.01 millibar, most preferably less than 0.001 millibar, and most preferably less than 0.0001 millibar. Specifically, the fixing elements can be controlled individually or in groups.

[0124] The receiving device according to the invention may alternatively or additionally include sensors to measure the physical and / or chemical properties between the fixed substrate and the receiving device. Such sensors are, for example, temperature sensors, pressure sensors, or distance sensors. It is also conceivable to incorporate a plurality of different types of sensors. Furthermore, sensors may also be disposed on other parts of the device. For example, a distance sensor or a pressure sensor may be disposed between the receiving devices. Specifically, the distance and / or a force between the substrate having the imprinting material and the mold or mold structure can be measured.

[0125] Furthermore, the contour of the receiving surface can be recessed relative to the receiving plane of the receiving surface as needed, thereby reducing the size of the receiving surface or changing its recess. Therefore, substrates (product substrates) that are structured or processed on both sides can also be used.

[0126] In a further embodiment, the housing is configured such that the substrate and / or structured mold can be heat-treated over the entire area or in sections. The housing can be heat-treated within 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.

[0127] An embodiment of the substrate receiving device according to the present invention can also handle a substrate and a liquid layer thereon. Specifically, the liquid layer is a liquid imprinting paint or imprinting material located at the interface during contact.

[0128] Specifically, the imprinting material is applied over the entire area or as droplets at defined intervals onto a substrate or structured mold. The imprinting material is preferably applied onto the substrate. More imprinting material or more droplets may also be used to define the area, depending on the topology of the substrate or structured mold. Specifically, the application of the imprinting material can be performed using a metering device with a nozzle, which can be configured between the structured mold and the substrate.

[0129] In another embodiment, the method can be used in conjunction with existing industrial coating processes such as spin coating. Coating can be performed separately from the imprinting process in a single module. Therefore, substrate coating can be fast, defect-free, full-area, particle-free, and standardized. Specifically, this results in yield advantages.

[0130] In another embodiment, the receiving device preferably includes, at its center, a means for bending, particularly partially fixed, the structured mold and / or substrate. The bending means refers to a bending element. Specifically, the bending element is a nozzle through which a fluid (preferably a gas) can exit to generate, for example, an overpressure between the structured mold and the receiving device, which bends the structured mold. The curvature of the structured mold is caused by the fact that it is preferably fixed circumferentially to the receiving device by vacuum.

[0131] According to the invention, imprinting begins after contact (preferably over the entire area of ​​the contact surface of the substrate and the structured mold having the imprinting material) and thus after capillary forces begin, particularly due to the removal of the substrate. Simple Explanation of the Diagram

[0132] Other advantages, features, and details of the invention will be illustrated below with the aid of drawings, based on preferred embodiments. In the drawings, schematically:

[0133] Figure 1a shows a cross-sectional view of one of the apparatuses in the first embodiment of the method.

[0134] Figure 1b shows a cross-sectional view of one of the apparatuses in a first embodiment of a method for bringing a structured mold and substrate holder close to one end point without external contact pressure.

[0135] Figure 1c shows a cross-sectional view of one of the apparatuses in the first embodiment of the method, wherein the substrate is detached from the substrate receiving device by means of the vacuum in the interrupted vacuum track and is adhered to the structured mold in a conformal manner due to capillary force.

[0136] Figure 1d shows a cross-sectional view of one of the structured mold receiving devices in a first embodiment of the method after embossing or manufacturing, wherein the curable embossing material is cross-linked or cured in a stack by UV light, particularly through a transparent structured mold.

[0137] Figure 1e shows a cross-sectional view of one of the apparatuses after imprinting, where the removal of the structured mold and substrate from the molding position has been performed after the imprinted substrate has been reattached to the substrate receiving apparatus.

[0138] Figure 2 shows a cross-sectional view and an enlarged view of one of the devices in the first embodiment of the method.

[0139] Figure 3a shows a second cross-sectional view of one of the apparatuses of the first embodiment of the method, wherein the substrate is detached from the substrate receiving device by means of a vacuum interruption in the vacuum track and is adhered to the structured mold in a conformal manner due to capillary forces.

[0140] Figure 3b shows a cross-sectional view of one of the apparatuses after imprinting, where the removal of the structured mold and substrate from the molding position has been performed after the imprinted substrate has been reattached to the substrate receiving apparatus.

[0141] Figure 4a shows a cross-sectional view of an apparatus according to a second embodiment of the method of the present invention.

[0142] Figure 4b shows a cross-sectional view of one of the apparatuses in the second embodiment of the method after imprinting and curing.

[0143] Figure 4c shows a cross-sectional view of one of the apparatuses in the second embodiment of the method after removal from the molding position.

[0144] Figure 4d shows a cross-sectional view of one of the apparatuses in a second embodiment of the method in the second repeating step of a step-by-step repeating imprinting process. Implementation

[0145] In the diagram, identical components or components with the same function are labeled with the same element symbol. The diagram is not shown to scale for ease of representation.

[0146] Figure 1a shows a cross-sectional view of one of the devices in a first embodiment. Specifically, Figure 1a shows receiving devices 5 and 6 for receiving a structured mold 2 and a substrate 1. Specifically, the receiving surfaces of receiving devices 5 and 6 are adapted to the size and circumferential contour of the structured mold 2 and the substrate 1.

[0147] In a preferred embodiment, the structured mold 2 from Figures 1a to 1e is an elastomeric soft mold 2. The elastomeric structured mold 2 achieves conformal and uniform contact on a large surface. To ensure good separation between the structured mold 2 and the substrate 1, the mold surface has the lowest possible surface energy.

[0148] The elastomeric structured mold 2 is supported by a carrier or mold carrier substrate 4 as needed. In another embodiment, glass carrier substrates of different thicknesses are used. Due to the use of a mold carrier substrate 4, the elastomeric structured mold 2 at least partially loses its flexibility. On the other hand, the flexibility of the structured mold 2 can be controlled by selecting the carrier 4. In an alternative embodiment, the carrier 4 can be a plate. In a third embodiment, the carrier 4 is not required. The structure of the structured mold 2 is not limited to the embodiments from Figures 1a to 1e.

[0149] The structures 3 and 3' of the structured impression 2 have dimensions in the micrometer and / or nanometer range. In a preferred embodiment, the structured impression 2 is fixed by vacuum or negative pressure via a vacuum track 8 of a vacuum device (not shown). In an example of the embodiment according to Figures 1a to 1e, negative pressure is applied to fix the structured impression while a plurality of vacuum tracks 8 operate concentrically with each other and cover the receiving surface of the impression receiving device 5 for receiving the structured impression. In an alternative embodiment, the vacuum track 8 is located only in the region of one side edge of the receiving surface of the impression receiving device 5. In this alternative embodiment, only an outer annular section of the receiving surface of the impression receiving device 5 is provided for fixing the structured impression 2 by means of the vacuum track 8.

[0150] In one of the preferred embodiments according to Figures 1a to 1e, substrate 1 is very thin compared to substrates in the prior art, thus providing flexibility. In this first embodiment, a carrier-free substrate is used to stabilize substrate 1 or the product substrate. The thin substrate 1 is fixed to a receiving device 6 to facilitate handling. 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 thinner and therefore has sufficient flexibility. Thus, the substrate to be imprinted is flexible.

[0151] In a preferred embodiment, the substrate from Figures 1a to 1e is a very thin substrate. Specifically, the thickness of substrate 1 is between 1 µm and 2000 µm, preferably between 10 µm and 750 µm, and more preferably between 100 µm and 500 µm.

[0152] The thicknesses of the structured mold 2, substrate 1, and imprinting material 7 are not shown to scale in the figure for ease of representation.

[0153] The receiving surface of the substrate receiving device 6 from FIG1a is at least substantially adapted to the size of the substrate 1. In a preferred embodiment, the substrate 1 is fixed by vacuum or negative pressure via a vacuum track of a vacuum device (not shown) that serves as a fixing element 9.

[0154] In an example of the embodiment according to Figures 1a to 1e, a negative pressure is applied to fix the substrate 1 when a plurality of fixing elements 9 operate concentrically with each other and cover the receiving surface of the substrate receiving device 6 for receiving the substrate 1. Specifically, the fixing members are also constructed as individually controllable fixing elements that are particularly evenly distributed on the receiving surface and divided into several regions. In Figures 1a and 1b, the fixing elements 9 in the region of one side edge of the receiving surface of the substrate receiving device 6 are initially controlled and activated individually (controlled or activated by arrows). Specifically, the edge region extends to 1 / 2 radius of the receiving surface, preferably up to 1 / 4 radius.

[0155] The substrate according to Figure 1a has been coated with an imprinting material 7 over its entire surface. In a preferred embodiment, the method is used in conjunction with existing industrial coating processes such as, for example, spin coating. The layer is applied, in particular, using spin coating, spray coating, or inkjet coating processes, as well as dip coating or roll coating processes. Coating can be performed separately from the imprinting process in a separate module.

[0156] In one alternative embodiment according to FIG. 2, a metering device 13 with a nozzle 12 disposed between the structured mold 2 and the substrate 1 can be used to apply the imprint material 7'. In this embodiment, the imprint material 7' is applied as droplets onto the substrate 1 at defined distances. The volume of the droplets is precisely measured and controlled so that the thickness of one possible intermediate layer remaining between the structural recess of the imprint structure and the substrate surface is adjusted. It is preferable that the intermediate layer thickness is as small as possible. Preferably, the intermediate layer thickness is between 50 µm and 0.01 nm, more preferably between 10 µm and 0.01 nm, and most preferably between 1 µm and 0.01 nm.

[0157] In one embodiment, the substrate receiving device 6 is also capable of handling the substrate 1 and a liquid layer thereon. Specifically, the liquid layer is a liquid imprinting paint or imprinting material 7, 7' located at the interface during contact.

[0158] Figure 1b illustrates the apparatus in a further procedural step. After alignment, the contact surfaces of the substrate 1 and the structured mold 2 are brought closer together and made in contact over the entire area.

[0159] In one embodiment of the invention, the structured mold 2 and the substrates 1 and 1' undergo a near-relative movement. Preferably, only one of the receiving devices 5 and 6 is moved. Preferably, only the structured mold 2 is advanced relative to the static substrate receiving device 6.

[0160] In the step of bringing the structured mold 2 and the substrate 1 into contact according to Figure 1b, only the fixing members in the edge region of the substrate receiving device 6 are used. Once the structured mold 2 contacts the substrate 1, the substrate 1 coated with imprinting materials 7 and 7' is released and fixed by interrupting the vacuum. By reducing the negative pressure at the receiving surface, the substrate 1 can be removed in a controlled manner. Therefore, the fixing elements are controlled. The structured mold 2 remains unchanged and is fixed to the mold receiving device 5.

[0161] After detachment, according to FIG. 1c, substrate 1 continues to adhere to structured mold 2 due to capillary action or the capillary force exerted by imprinting materials 7, 7' present between substrate 1 and structured mold 2, and the imprinting process begins over the entire area. According to the invention, no additional external pressure is required for successful imprinting or manufacturing. According to the invention, by simply bringing the receiving devices 5, 6 closer together to reduce the distance H (see FIG. 2) to a precisely defined distance HE, the imprinting process can begin without the use of additional external pressure. Specifically, the final distance HE is less than 100 µm, preferably less than 10 µm, most preferably less than 500 nm, and most preferably less than 100 nm. Due to the capillary force, the thin, flexible substrate 1 is attracted toward the structured mold 2 in a conformal manner. Due to the flexibility of substrate 1 and the degrees of freedom gained through detachment of substrate 1, substrate 1 is deformable and adaptable to structured mold 2. Therefore, uniform contact is achieved during imprinting.

[0162] Figure 1c shows an apparatus having a UV-transmitting structured mold 2 mounted on a mold receiving device 5, wherein the substrate 1 on the structured mold 2 and the imprinting material 7 therebetween are held together by capillary force. For this purpose, the substrate 1 must have at least a high degree of flexibility. Due to the viscosity of the imprinting material 7, the intermediate space of the structured mold 2 is also completely filled due to capillary action.

[0163] In the embodiment according to FIG. 1c, after the fixation to the substrate receiving device 6 is interrupted and after the action of capillary force, the substrate 1 is no longer located on the receiving surface of the substrate receiving device 6. In a second embodiment (not shown in the figure), the substrate 1 remains located on the receiving surface of the substrate receiving device 6, without being (actively) fixed by the fixing member and without the action of capillary force. Whether there is still contact between the substrate 1 and the receiving surface of the substrate receiving device 6 after the substrate fixation is released by the fixing member 9 depends on a plurality of process parameters ab, such as (for example) the amount and viscosity of the imprinting materials 7, 7', the size of the structure 3, 3' of the structured mold 2, the adjustment of the final distance HE, etc.

[0164] In an alternative embodiment (not shown in the figures), the structured mold 2 is located on the lower receiving device and the substrate 1 is located on the upper receiving device. After separation, the substrate 1 continues to adhere to the structured mold 2 due to capillary forces (also caused by additional gravity) exerted by the imprinting material present between the substrate 1 and the structured mold 2, and is located on the imprinting material 7 applied to the structured mold 2 as droplets at defined distances.

[0165] In all the embodiments shown, no external pressure (specifically, no contact pressure) is required to achieve a conformal or seamless contact between the structured mold 2 and the substrate 1 with the imprinting material 7. The device has the advantage of not requiring the use of an actuator to apply a force to the mold 2 and / or the substrate 1 using a force for transferring the mold structure 2 and resulting in a force orthogonal to the substrate contact surface.

[0166] The method prevents deformation of structure 3 of the structured mold 2 caused by contact pressure. Furthermore, the flexibility of the substrate 1 can compensate for the irregularities of the structured mold 2 and / or the substrate 1 and also prevent further imprinting defects (such as imprinting defects caused by air inclusions), thus the quality of the imprinting process is very high.

[0167] In the next step of the procedure according to Figure 1d, the direct cross-linking of the curable imprinting material 7 (specifically, a photoresist or varnish) is carried out by UV light 10. Generally, curing can be carried out by electromagnetic radiation, by heat, by electric current, by magnetic field, or other methods. Preferably, curing is carried out through a transparent impression receiving device 5 and a transparent structured impression 2. It is also conceivable to cure the imprinting material 7 by a radiation source in or on the impression receiving device 5.

[0168] In the final procedure step according to Figure 1e, the substrate 1 and the structured mold 2 are removed from their self-forming positions. Before removal, the substrate 1 is fixed back onto the substrate receiving device 6. The substrate 1 is fixed by vacuum or negative pressure via a fixing element 9' of a vacuum device (not shown in the figure).

[0169] For removal from the molding position, use and activate (activation is indicated by arrows) all the fixing elements of the substrate receiving device 6, specifically, the fixing elements 9' that are individually controllable and uniformly distributed on the receiving surface.

[0170] Figure 1e shows the imprinted and cured imprinted material 11 on the substrate 1 after imprinting 1i. The method achieves high-resolution structuring in the sub-µm range, preferably less than 20 µm, more preferably less than 2 µm, more preferably less than 200 nm, and most preferably less than 10 nm.

[0171] Preferably, the device includes a group of modules that have a shared working space that requires visibility to be sealed relative to the surrounding atmosphere. The modules (e.g., coating modules, molding modules, unloading modules) may be arranged in a cluster or star shape around a central module that has a mobile device (robotic system).

[0172] Figure 3a illustrates an embodiment of substrate deformation due to capillary action after contact between substrate 1' and structured mold 2 and the imprinting material 7 located between them. The proportions of individual components and substrate 1' in Figure 3a are disproportionate, particularly tracing back to the structure 3 of the structured mold 2, represented in a magnified manner. Due to capillary action, the thin, flexible substrate 1' is attracted toward the structured mold 2 in a conformal manner. Because of the flexibility of substrate 1' and the degrees of freedom gained from detaching substrate 1' from substrate housing 6, substrate 1' is deformable and adaptable to the structured mold 2. Therefore, uniform contact is achieved during imprinting. For this purpose, at least substrates 1 and 1' (preferably substrates 1, 1' and structured mold 2) must have a high degree of flexibility. Due to the high flexibility and conformal contact of substrates 1 and 1', imprinting defects are reduced or preferably eliminated.

[0173] Imprinting defects that can occur in prior art nanoimprinting include cracks, irregularly filled imprint structures (i.e., air inclusions), and uneven paint layer thickness. Adhesion between the imprinting material (e.g., paint) and the structured imprint is critical, because if, for example, the cured imprinting material 11' adheres more strongly to a recess in the structured imprint 2, twisting or cracking can occur, causing an imprint structure to tear during removal from its formed position. Irregularly filled imprint structures 2 result in defects in individual imprint structures within the cured imprinting material 11'. The filling of the imprint structure depends, in particular, on factors such as the viscosity of the imprinting material 7, the thickness of the coating, or the size and arrangement of the applied imprinting material droplets and the timing.

[0174] Specifically, further imprinting defects originate from defects in the structured mold 2 itself, such as (e.g.) a small depth or an uneven surface in some locations of the structure 3. Defects such as (e.g.) an uneven surface in the structured mold 2 are compensated for by the flexibility of the substrate 1.

[0175] According to the present invention, the soft-structured mold 2 will not deform during the process because no external pressure is applied. The substrates 1 and 1' are so thin that mold defects or defects that would have occurred in the prior art can be compensated for or even eliminated. Figure 3b shows the imprinted and cured imprint material 11' on the substrate 1i after removal from the molding position.

[0176] Specifically, the proposed invention can be used to manufacture the following products: - 1D, 2D and / or 3D diffractive optical elements (DOE) - Microfluidic components, - Lenses and lens systems - Fresnel lens, - Biomedical components, - Polarizer, - Nanostructured electrodes, - IR waveguide, - Angular optical devices for virtual reality applications - Fiber optic connection, - Working impressions used in embossing microfilming - and others.

[0177] Figures 4a to 4d illustrate another embodiment of a step-by-step repeating process. A structured mold 2' smaller than the substrate 1'' on which the structure will be imprinted is used. According to Figures 4a to 4d, the process is repeated frequently or as many times as needed to imprint the entire substrate 1'' using the imprinting material 7''. The apparatus according to the invention can preferably be installed in a processing chamber that is hermetically sealed relative to the surrounding environment. Therefore, it is possible to evacuate the processing chamber and / or ventilate the processing chamber with any gas or gas mixture.

[0178] Figure 4a shows a substrate 1'' with a layer of imprinting material 7'' covering the entire area. In another embodiment, droplets of imprinting material can be applied to the substrate 1'' at defined intervals. The stepwise repeatable structured mold 2' is smaller than the substrate 1''. Specifically, Figure 4a also shows a cross-sectional view of a receiving device 5' for accommodating one of the means of accommodating the structured mold 2'. The structure 3' of the structured mold 2' has dimensions in the micrometer and / or nanometer range. In a preferred embodiment, the structured mold 2' is fixed to the mold receiving device 5' by a vacuum or negative pressure via a fixing element of a vacuum device (not shown).

[0179] In one advantageous embodiment of the invention, the specified device includes a curing member (specifically, segment-by-segment) for curing the imprint substrate 1'', the segments preferably corresponding to a step-by-step repeating process, specifically, corresponding to an imprint area of ​​a structured mold.

[0180] The step-repeat device is considered a further development of the device described in patent specification EP2287666A1. EP2287666A1 describes a step-repeat device for imprinting a substrate in a plurality of imprinting steps within an imprinting process, and further means included in the device, specifically, an adjustment device.

[0181] In the procedure steps according to Figure 4b, the imprinting material 7'' is structured by a stepwise repeating structured mold 2'. The structured mold 2' is moved to a first position for imprinting in this first position. Preferably, the structured mold 2' is brought close only to the static carrier substrate. After contact, the direct crosslinking of the imprinting material 7'' (specifically, a photoresist or varnish) can be cured by UV light 10. Generally, curing can be carried out by electromagnetic radiation, by heat, by electric current, by magnetic field, or other methods. Preferably, curing is carried out through a transparent mold receiving device 5' and a transparent structured mold 2'. According to the invention, it is also conceivable to cure the imprinting material 7'' by a radiation source in or on the mold receiving device 5'.

[0182] After removing the self-forming position according to Figure 4c, a cured imprinting material 11' is used to imprint the defined section of the substrate 1''.

[0183] In a further step of the stepwise repeating process according to Figure 4d, the stepwise repeating structured mold 2' moves from a first position to a second predefined position different from the first position and is imprinted again. After contact, the direct crosslinking of the imprintable curable imprint material 7'' is carried out by UV light 10. According to the invention, multiple curing is also conceivable, wherein the first curing is carried out locally after each individual imprinting step, and after the stepwise repeating process is completed, further curing of the entire substrate 1'' is carried out (for example) in a separate module.

[0184] The procedure according to Figures 4a to 4d can continue until the desired area of ​​the substrate 1'' has been imprinted. In this embodiment, the structured mold 2' can imprint without external force after contacting the imprinting material 7'' on the substrate 1''. The structured mold has a component for moving particularly parallel to the substrate surface and a lifting system for approaching along the Z direction and for removal from the forming position (not shown). The high precision of the positioning stage of the step-repeat device enables seamless imprinting using the structured mold 2' across the entire circumference of the substrate 1''. According to the invention, alignment with a previously imprinted structure (specifically, for example, an overlapping structure at the edge of a previously imprinted structure segment) is possible. The use of a continuous substrate in the step-repeat process is conceivable. Specifically, the continuous substrate is a substrate stored on a first roller, the length of which is many times greater than its width. Specifically, the continuous substrate is a film.

[0185] Lens arrays, such as (specifically) microlenses and / or nanolens arrays, are manufactured by imprinting repeated or performed in parallel using a structured mold 2'.

[0186] According to the present invention, no additional external pressure is required for successful imprinting. According to the present invention, the mold receiving device 5' is brought closer to the substrate 1'' only in a predefined position, such that the distance H is reduced to a precisely defined final distance H'E, allowing the imprinting process to begin without applying any additional external pressure. Specifically, the final position H'E is less than 100 µm, preferably less than 10 µm, most preferably less than 500 nm, and most preferably less than 100 nm. Through capillary action, the thin, flexible substrate 1'' is attracted toward the structured mold 2' in a conformal manner. Due to the flexibility of the substrate 1'', the substrate 1'' is deformable and adaptable to the structured mold 2'. Therefore, uniform contact is achieved during imprinting.

[0187] 1: Substrate / Product Substrate 1': Substrate / Product Substrate 1'': Substrate / Product Substrate 1i: Substrate after imprinting 2: Structured impression / impression structure 2': Structured Imprint 3: Embossing Structure 3': Embossing structure 4: A substrate or backplate used for stabilizing the printing plate carrier. 5: Imprint receiving device 5': Imprint receiving device 6: Substrate receiving device 7: Imprinting material 7': Imprinting material 7'': Imprinting material 8: Vacuum track in the mold-containing device 8': Vacuum track in the mold housing device 9: Fixing elements in the substrate housing device 9': Fixing element in substrate housing device 10: Radiation source 11: Imprinting and curing materials 11': Imprinting material that has been imprinted and cured 12: Nozzle 13: Measuring device H: Distance HE: Final Distance H'E: Final distance

Claims

1. An apparatus for fabricating microstructures or nanostructures, comprising: A substrate receiving device (6) configured to receive a substrate (1, 1', 1'') having an imprinting material (7, 7', 7''); a structured mold (2, 2') configured to contact the imprinting material (7, 7', 7''); at least one sensor; and a control unit configured to move the structured mold (2, 2') relative to the substrate (1, 1', 1'') having the imprinting material (7, 7', 7'') based on a value measured by the at least one sensor, so that the structured mold (2, 2') contacts the imprinting material (7, 7', 7'').

2. The apparatus of claim 1, wherein the at least one sensor is configured to measure at least one of pressure, distance and temperature.

3. The apparatus of claim 1, wherein the relative movement includes creating or reducing a gap between the structured mold (2, 2') and the substrate (1, 1', 1'').

4. The apparatus of claim 1, wherein the contact is performed under no pressure.

5. The apparatus of claim 1, wherein the contact is performed without additional contact pressure.

6. The apparatus of claim 1, further comprising at least one actuator configured to adjust the substrate receiving device (6) or a mold receiving device (5, 5'), wherein the control unit is configured to control the at least one actuator based on a value measured by the at least one sensor.

7. The apparatus of claim 1, further comprising at least one fixing element (9, 9') configured to fix the substrate (1, 1', 1'') to the substrate receiving device (6).

8. The apparatus of claim 7, wherein the control unit is configured to control the at least one fixed element (9, 9') based on a value measured by the at least one sensor.

9. The apparatus of claim 8, wherein the control unit is configured to control the at least one fixing element (9, 9') such that after the structured mold (2, 2') comes into contact with the imprinting material (7, 7', 7''), the fixing of the substrate (1, 1', 1'') is at least partially cancelled.

10. The apparatus of claim 7, wherein the at least one fixing element (9, 9') is configured to fix the substrate (1, 1', 1'') by vacuum or negative pressure.

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