System and method for imprinting

Abstract

The invention relates to a system for imprinting, in particular nanoimprinting, comprising at least one substantially flexible stamp configured for imprinting, in particular nanoimprinting, at least one roller configured for exerting pressure onto at least one substantially flexible stamp and / or onto at least one substrate which is to be imprinted, at least one stage configured for providing support for at least one substrate during imprinting and at least one frame, wherein at least one roller is connected or connectable to at least one frame in a frictionless manner.

Description

[0001] System and method for imprinting

[0002] The invention relates to a system for imprinting, in particular nanoimprinting. The invention also relates to a method for imprinting, in particular nanoimprinting.

[0003] When producing products via an imprinting process, and in particular nanoimprinting, it is a challenge to obtain a high repeatability. Due to the relatively small structures, which can range for example from 500 micrometer down to 25 nanometer, the alignment requires a high level of accuracy and several internal and external factors can affect the final result of the imprint or could lead to several deviation between products produced via the same process. Many factors can affect the repeatability of the imprinting process. A way to improve the repeatability is to improve the alignment and / or via controlling the (external) conditions of the imprinting process. However, also active control of the process parameters does not ensure that the imprinting process has a high repeatability.

[0004] It is a goal of the invention to achieve a higher level of accuracy during imprinting, in particular during roll to plate imprinting, or at least to provide an alternative to the know solutions.

[0005] The invention provides thereto a system for imprinting, in particular nanoimprinting, comprising:

[0006] - optionally at least one substantially flexible stamp configured for imprinting, in particular nanoimprinting;

[0007] - at least one roller configured for exerting pressure onto at least one substantially flexible stamp and / or at least one substrate which is to be imprinted;

[0008] - at least one stage configured for providing support for at least one substrate during imprinting; and

[0009] - at least one frame; wherein at least one roller is connected or connectable to at least one frame via at least one air bearing.

[0010] The system according to the present invention benefits of the roller being connected and / or connectable to at least one frame via at least one air bearing such that a frictionless connection is achieved between the roller and the frame. At least one air bearing is in particular configured for enabling free movement in the rotary and / or axial and / or radial direction of the roller, preferably in both the rotary and axial direction. The use of at least one air bearing enables frictionless motion of rotation around the axle of the roller and / or axial motion along the axle of the roller and / or radial motion perpendicular to the axle of the roller. In particular, the air bearing enables frictionless motion of the roller with respect to the frame and / or at least one stage, in particular the part of the stage configured to support at least one substrate to be imprinted. Conventional roller based bearings typically have a roller suspended by conventional ball bearings, which enable rotation of the imprint roller around the axle, but prevent axial motion. Ultimately, the degree of freedom enabled by the air bearing(s) prevents the roller and / or the substantially flexible stamp of being over constrained, and / or subjected to an excessive mechanical stress. In particular the application of air bearing(s) result in a relatively high radial stiffness and / or a relatively high radial accuracy of the roller and / or the substantially flexible stamp. Mechanical stress may cause unwanted deformation of the substantially flexible stamp causing a dimensional distortion of the final product. By preventing mechanical stress to build up in the flexible stamp the overlay accuracy of the (nano)imprinting process is improved within a single cycle and within a single batch of imprints. Mechanical stress is typically introduced by assembling a new substantially flexible stamp in the system, during the imprint cycle, and / or occurs over multiple imprint cycles. The system according to the present invention passively prevents build-up of mechanical stress, resulting in an overall more robust and repeatable behaviour of the components of the system and thus of a more accurate and repeatable imprinting process. A major indicator of this improvement is the improved overlay accuracy which can be attributed to at least one roller being connected or connectable to at least one frame via at least one air bearing. To achieve a higher repeatability on overlay accuracy a typical design strategy would be to focus on active solutions such as an active alignment control and / or by providing a stiff or rigid apparatus design to have a high level of control on the behaviour of the flexible stamp. The use of at least one air bearing is counter intuitive as applying a passive solution enables more motion compared to a fixed shaft. This system according to the present invention is therefore a creative and counterintuitive solution to the technical challenge of achieving a higher level of accuracy during imprinting, in particular during roll to plate imprinting. At least one air bearing could for example be an aerostatic bearing and / or an aerodynamic bearing. At least one air bearing can for example comprise a (thin) film of pressurized gas enabling frictionless motion. The air bearing(s) in particular provides a low friction and stiff load-bearing interface, or even frictionless interface between surfaces. The use of a frictionless bearing can avoid the traditional bearing-related problems of friction, wear, particulates, and lubricant handling, and offer distinct advantages in precision positioning, such as lacking backlash, loadcarrying capacity and static friction, as well as in high-speed applications. It is for example imaginable that at least one air bearing, and preferably each air bearing, is filled with a medium, such as air or a medium comprising air.

[0011] At least one roller can for example be suspended in at least one frame. At least one frame could also be referred to as a housing. At least one roller is in particular and imprint roller. The system according to the present invention could also be applied in an embossing or transfer process. The system according to the present invention has the benefit that it does not require a temperature change of the equipment and / or the (direct) environment during imprinting and / or curing. Instead, the system according to the present invention is in particular configured to keep the thermal conditions at least during imprinting and / or at least curing substantially constant and / or at predetermined conditions. The system according to the present invention particularly deviates from hot embossing, wherein relatively large temperature fluctuations are needed for imprinting wherein the temperature is elevated above the glass transition temperature of a substrate to allow imprinting and / or wherein the temperature is decreased below the glass transition temperature of a substrate to allow the imprinted substate to cure.

[0012] In a preferred embodiment, at least one roller is connected or connectable to at least one frame via at least two air bearings. The use of at least two air bearings could positively contribute to the stability of the system, and in particular to the stability of the roller within the system. It is in particular beneficial if at least one roller comprises two distal ends, and wherein each distal end of the roller is connected or connectable to at least one frame via at least one air bearing. In this way, a stable configuration of the roller within the system is provided. It is for example imaginable that at least one roller comprises a shaft and wherein said shaft is connected or connectable to at least one frame via at least one air bearing. Preferably, the shaft is connected to the frame via two air bearings provided at each distal end of the shaft. The shaft could also be referred to as an axle, and / or the shaft could define an axle. It is for example imaginable that each air bearing is aligned with the shaft of the roller.

[0013] In a beneficial embodiment, the system comprises at least one actuator. At least one actuator can for example be configured to apply a force, in particular a pressure, to at least one air bearing. The use of at least one actuator can further contribute to a stable positioning and retaining of said stable position of the roller within the frame during the imprinting process. Preferably, at least one air bearing is positioned in line with at least part of at least one actuator and / or with at least part of at least one roller, in particular a shaft of said roller. It is for example possible that at least one air bearing is positioned in line with the shaft and / or axis of at least one roller. It is for example possible that the central axis of at least one air bearing overlaps with the shaft and / or axis of at least one roller. This configuration contributes in to a higher level of accuracy during imprinting by passively control alignment. Therewith, the control on the behaviour of the flexible stamp is further improved. In a further preferred embodiment, the system comprises at least two actuators, wherein at least one actuator and preferably each actuator is configured to apply a force, in particular a pressure, to at least one air bearing. Preferably, the system comprises at least two actuators wherein a first actuator is configured to apply a force, in particular a pressure, to a first air bearing at a first distal end of the roller and wherein a second actuator is configured to apply a force, in particular a pressure, to a second air bearing at a second distal end of the roller. Preferably, a symmetrical configuration is applied to further enhance the accuracy and stability of the system. It is for example imaginable that a first actuator and a second actuator are configured to apply a force, in particular a pressure, to the shaft of the roller via each air bearing. This results in that the roller is able to move axially whilst the actuators maintain their position. As a result, the imprint pressure can remain uniform even though the roller is moving relative to the frame and / or the substrate which is to be imprinted. Within the context of the present invention, the imprint force is preferably within the range of 0-2,5 kN. The imprint pressure is preferably in the range of 10-50 N / cm, in particular in the range of 20-40 N / cm, for example substantially or at most 30 N / cm. Axial movement of the roller can be introduced by the means above, namely stress present in the substantially flexible stamp and / or (mechanical) stress in the imprint process. The use of at least one actuator and preferably two actuators can prevent that the stresses cause a negative effect to the components of the system and / or to the final product. In particular, the use of at least one actuator and preferably two actuators limits, in particular prevents, force variations and / or movement variations resulting from movement of the roller which causes a negative effect to the components of the system and / or to the final product. It is also imaginable that at least one actuator is configured to control the position control of at least one roller and / or at least one flexible stamp for example by determining and / or controlling the position of at least a part of the actuator and / or the position of the roller. The at least one actuator may displace the imprint roller in a direction which is substantially perpendicular to the imprint surface and / or substrate. The roller can therefore be lifted up and / or down in particular to allow a gap for the substrate. The gap can be variable to allow different substrate thicknesses to be imprinted, or to remove contact of the roller with the substrate. In practical sense, the imprint roller can be pressed onto or lifted from the substrate at the start or end of the cycle. Preferably, at least one actuator is configured to control the positioning of at least one roller and / or at least one flexible stamp with a positioning accuracy of 1 pm or less, preferably 0.5 pm, 1 pm or less. Therewith, a sufficient imprinting accuracy, in particular nanoimprinting accuracy, can be achieved. The range of motion of at least one actuator, or each actuator, is preferably within the millimetre range. The range of motion of at least one actuator is preferably greater than 1 mm, more preferably greater than 5 mm, even more preferably greater than 10 mm. It is also possible that the range of motion is at least or substantially 12 mm. The actuator stiffness of at least one actuator, or each actuator, is preferably between 1 *105and 1*107N / m. The actuator stiffness relates elongation of the at least one actuator to force. Depending on the design a particularly low stiffness could be preferred to have small changes in imprint force when variations in the imprint cycle occur. At least one actuator may be configured to control the positioning of at least one roller with respect to the stage, in particular to the substrate to be imprinted. At least one actuator can be a (mechanically) spring loaded actuator and / or a pneumatic actuator and / or a hydraulic actuator and / or an electric actuator and / or a Lorentz actuator and / or a (permanent) magnet actuator and / or a piezo element. At least one actuator, or each actuator, could for example be or comprise a servo motor controlled actuator or a stepper motor controlled actuator, in particular at least one actuator, or each actuator, which is configured for controlling the position of at least one roller and / or at least one flexible stamp. The system could further comprise at least one drive unit, for example for driving at least one actuator. The drive unit may for example be or comprise a stepper motor, a servo motor, a voice coil, a linear motor, an ac motor, a de motor or a (permanent) magnet motor. It is imaginable that the system further comprises a transmission connected to at least one drive unit. The transmission is preferably located between at least one drive unit and at least one actuator. The transmission may for example be a spindle, a gearbox or a gearing mechanism. The applied transmission is typically dependent on the design of the device. A rotary motion of the drive unit can be translated to linear motion of the imprint roller, for example up and / or down. In case the transmission is not a 1 :1 ratio, the transmission can be used to gear up and / or down the drive unit.

[0014] In a further preferred embodiment, at least one roller and at least one stage are mutually displaceable in an imprint direction in particular such that imprinting is facilitated. Preferably, the mutual distance between at least one roller and at least one stage is adjustable. At least one roller and at least one stage are in particular mutually displaceable in an imprint direction and / or the inverse thereof such that imprinting is facilitated. Typically, at least one roller and at least one stage are also displaceable in distance with respect to each other. It is for example imaginable that at least one roller and / or at least one stage are displaceable in vertical direction. It is imaginable that the mutual distance between at least one roller and at least one stage is adjustable. In a preferred embodiment, at least one stage is displaceable with respect to at least one roller. It is for example imaginable that at least one stage is displaceable in imprint direction and / or the inverse thereof, in particular such that imprinting is facilitated. It is also possible that at least one stage is substantially stationary and that at least one roller is displaceable with respect to said stage. It is also imaginable that the system comprises at least one secondary actuator for adjusting the mutual position of at least one roller and at least one stage. At least one roller and at least one stage can for example be mutually displaceable by means of at least one secondary actuator. The system, and in particular the secondary actuator, may further comprise at least one drive unit. The secondary actuator can be configured for adjusting the mutual distance between the stage and the roller and / or the mutual displacement in the imprint direction such that imprinting is facilitated.

[0015] It is conceivable that the system comprising multiple rollers configured for exerting pressure onto at least one substantially flexible stamp and / or at least one substrate which is to be imprinted, wherein at least two rollers are connected or connectable to at least one frame via at least one air bearing. In case multiple rollers are applied, it is beneficial if at least two rollers and preferably each roller is connected or connectable to at least one frame via at least one air bearing. It is for example imaginable that at least one substantially flexible stamp is mounted or mountable within the system over multiple rollers. Each roller can thereby be configured for exerting pressure onto at least one substantially flexible stamp and / or at least one substrate which is to be imprinted. It is imaginable that multiple rollers are configured to co-act with the same substantially flexible stamp. In yet another possible embodiment it is conceivable that the system comprises at least two substantially flexible stamps, wherein typically each substantially flexible stamp is configured to co-act with at least one roller.

[0016] In a further possible embodiment, the system comprises multiple rollers configured for exerting pressure onto at least one substantially flexible stamp over and / or at least one substrate which is to be imprinted, wherein at least one roller is connected or connectable to at least one frame via at least one further type of bearing. Non-limiting types of bearings which could be applied are roller bearings, ball bearings, plain bearing, linear bearing, fluid bearings and / or magnet bearings. Any of these bearings could also be used as an alternative to the air bearing(s). The system could optionally comprise at least one reference roller. It is for example imaginable that at least one further bearing, in particular not being an air bearing, is used for at least one reference roller.

[0017] Optionally, at least one stage can be connected or connectable to at least one frame. This could further contribute to a stable and solid embodiment, wherein deviations during the imprinting process caused by the components of the system itself can be prevents. Such embodiment could also positively contribute to the repeatability of the imprinting process. The system according to the present invention is in particular configured for roll-to- plate imprinting, in particular roll-to-plate nanoimprinting. The system is preferably configured such that at least one substantially flexible stamp can be decoupled from the system, and in particular from the roller. The substantially flexible stamp is in particular at least partially detachable wrapped around at least one roller. It is for example imaginable that at least one roller is configured for rolling at least one substantially flexible stamp over at least one substrate which is to be imprinted. At least one roller is thereby configured for co-action with at least one substantially flexible stamp which is configured for imprinting. The substantially flexible stamp preferably comprises at least one polymer. It is also possible that at least part of at least one substantially flexible stamp is made of at least one polymer material. It is conceivable that the substantially flexible stamp can be used in a repeated and / or cyclic imprint process. The present invention in particular provides a passive solution for improving the accuracy of the imprinting process. Conventional passive solutions typically use unconstrained motion of the imprinting roller to prevent mechanical stress to build up in the discrete flexible mould from cycle to cycle.

[0018] The system according to the present invention preferably comprises at least one resin applicator for applying at least one resin, in particular at least one curable resin, more in particular at least one crosslinkable resin, to at least one substate and / or at least one flexible stamp. According to this embodiment, the system is able to produce a textured, or patterned, final product by pressing a substantially flexible stamp, containing a texture, onto a substrate with a resin in between. After the texture is transferred an applied resin, the resin can be cured, for example via UV curing. The flexible stamp and the imprinted substrate can subsequently be separated. The application of at least one resin is beneficial as it enables the system to apply a texture or pattern, onto a substrate without the need of elevating and / or lower the temperature above and / or below the glass temperature of the substrate. Hence, this embodiment contributes to keeping the thermal conditions of the system at least during imprinting and / or curing substantially constant and / or at predetermined conditions, which improves the process stability and repeatability. The system may also be configured to keep the viscosity of the at least one applied resin constant during imprinting and / or over several imprinting cycles, which further contributes to the process stability, repeatability and (imprinting) accuracy. At least one substantially flexible stamp preferably comprises at least one textured area. The textured area can for example comprise a texture with dimension in the range from 500 micrometer down to 25 nanometer. At least part of the texture is preferably an optically active texture. It is for example imaginable that at least a central part of the substantially flexible stamp comprises a textured area. The substantially flexible stamp is in particular configured for nano-imprint lithography transfer processes. However, it is also imaginable that at least one substantially flexible stamp is substantially plain. This is for example beneficial in case the substantially flexible stamp is applied for the transfer of objects. In a preferred embodiment, at least one substantially flexible stamp comprises at least two opposing edges. It is for example imaginable that at least one flexible stamp comprises two pairs of opposing edges, or side edges. In a beneficial embodiment, at least one substantially flexible stamp comprises at least two substantially rectilinear side edges. Such configuration will enable easy positioning and / or attaching of the flexible stamp. It is for example imaginable that at least one substantially flexible stamp is substantially rectangular and / or elongated. Typically, the length direction of the substantially rectangular or elongated flexible stamp is oriented in the imprint direction. It is for example possible that at least one roller and / or at least part of the frame and / or at least part of the stage is attached to the substantially flexible stamp. The system could further comprise at least one adjusting element configured for adjusting the position of at least one substantially flexible stamp with respect to at least one stage. For example for adjusting the height and / or orientation of at least one stamp with respect at least one stage.

[0019] Optionally, the system could comprise at least one heater and / or a cooler for heating and / or cooling of at least part of at least one roller, in particular for heating and / or cooling at least part of the flexible stamp and / or for heating and / or cooling at least part of the substrate. Heating and / or cooling at least part of the roller could further optimize the imprinting process.

[0020] The system preferably comprises one or more sensors. It is for example imaginable that the system comprises at least one temperature sensor, tension sensor, pressure sensor, position sensor and / or combinations thereof. In a preferred embodiment, the system comprises at least one tension sensor for monitoring the tension in the substantially flexible stamp. At least one tension sensor can for example be configured to measure the dynamical tension in the flexible stamp at least during imprinting and / or to regulate the tension of the flexible stamp during imprinting. At least one sensor, in particular at least one pressure sensor, can for example comprise a load cell and / or a piezoelectric force sensor. At least one load cell can be configured to measure a pressure, strain, force and / or tension in the substantially flexible stamp. The measuring and / or control of the tension in the substantially flexible stamp may further optimize the imprinting process. It is also imaginable that at least one sensor is configured to determine an imprint pressure. The imprint pressure can for example be determined by the pressure exerted by the roller. For example, at least one sensor can comprise at least one load cell and / or at least one piezoelectric force sensor configured to measure a pressure, strain, force and / or tension of the roller at least during imprinting. It is possible that at least one frame comprises at least one sensor and / or that at least one sensor forms part of the frame. It is also possible that at least one stage comprises at least one sensor and / or that at least one sensor forms part thereof. The system could also comprise at least one position sensor. At least one position sensor can be configured to determine the position of at least one air bearing and / or of at least one roller. At least one position sensor is preferably configured to determine the position of at least one air bearing and / or at least one roller in the direction substantially perpendicular to imprint direction, in particular a (vertical) direction. A positioning sensor may for example comprise an encoder and / or a hall effect sensor and / or an inductive sensor. It is also imaginable that at least one position sensor is configured to determine the position of at least one actuator. In a preferred embodiment, the system comprises at least two position sensors, wherein at least one position sensor is present at each distal end of the roller. Each position sensor can be configured for determining the position of at least one actuator and / or at least one air bearing at a distal ends of the roller. Such embodiment can enable further control of the system, for example in order to determine and / or control if the roller is substantially parallel to imprint surface of the substrate and / or to determine and / or control if the roller is in a substantially horizontal and / or level orientation. Optionally, at least one position sensor can be configured to determine the position of at least one roller in the axial direction. The roller is preferably free to move in the axial direction, which typically occurs when mechanical stress is developed in the flexible stamp. As such, a position sensor on the axial direction can be indicative of stress developed within a single imprint cycle or over multiple cycles. Optionally, the system could comprise at least one a pressure sensor for determining and / or controlling the imprint pressure applied by at least one roller. The imprint pressure of at least one roller could for example be determined via the shaft of at least one roller. It is imaginable that at least one actuator is actuated based upon data and / or at least one measurement of at least one sensor.

[0021] As indicated above, at least one actuator can be configured for controlling the position and / or pressure of at least one roller and / or at least one flexible stamp. It is imaginable that at least one actuator has a sub-system for controlling the position or pressure of at least one roller and / or flexible stamp. During an imprint cycle one of two modes can be chosen in which one of the two sub-systems will become leading for the control loop. The two modes of imprinting can be pressure control and position control. Pressure control can be based upon a feedback loop configured for minimizing the error of a pre-defined pressure profile. This is typically used for uniform imprints with a substantially constant layer thickness. The input parameters can include direct or indirect measurement of the imprint pressure. In some situations, the pressure cannot be measured on the interface of the roller or the substrate which is to be imprinted. Therefore the pressure could optionally be measured at the nearest point, for example via the shaft of the roller. The method of measuring the pressure can vary per system. Non-limiting examples thereof are strain measurement, for example by making use of a load cell, pressure measurement of pneumatic actuators and / or position measurement of components, for example by making use of a piezoelectric force sensor. The chosen components are preferably components with a predefined stiffness such that displacement can be related to a determined force. The output parameter can depend on whether the pressure is regulated pneumatically or via a spring loaded solution. Position control can be based on a feedback loop configured for minimizing the error of a pre-defined position profile. Hence, it is imaginable that at least one actuator is configured for following a predetermined position profile. This route could for example be used for low pressure applications or non-flat products. The input parameter can be a position for example measured at the roller shaft. The output parameter can be a position of a spring loaded part or the position of a physical end-stop for the roller. The use of a two mode system has several benefits as it enables a larger range of applications, for example applying non-constant pressure and / or non-constant position profiled, or enabling imprinting of non-flat products. For extreme low imprint pressures a position controlled system could be more effective, for example by setting the roller height larger than the substrate thickness or larger than the substrate thickness in combination with the thickness of the flexible stamp. The two mode system further enables that at least one actuator can be switched from pressure to position control within a single imprint cycle. This could in practice for example be done by raising the roller at the end of the substrate and prevent overflow of the resin or resist, which is typically used during the imprinting process. Alternatively, this could in practice for example also be done by lowering the roller at the start or raising the roller at the end of the substrate. It is imaginable that at least one actuator is configured for operating in two modes and switching between these two modes within a single cycle.

[0022] The system according to the present invention could further comprise at least one control unit. It is imaginable that at least one control unit is configured for pressure and / or position control of at least one roller preferably based upon at least one pressure and / or positioned determined by at least one sensor. At least one control unit can be configured for lowering and / or lifting at least one roller, preferably in a substantially vertical manner, in order to make contact with at least one substrate which is to be imprinted and / or for applying a pressure, in particular a positive pressure, to said substrate during imprinting.

[0023] The invention also relates to a method for imprinting, in particular nanoimprinting, making use of at least one system according to the present invention, wherein at least one roller is rotated and / or axially displaced in a frictionless manner during imprinting. It is for example imaginable that the method according to the present invention aims to keep the thermal conditions at least during the imprinting step constant and / or at predetermined conditions. It is also imaginable that the method according to the present invention is configured to keep the thermal conditions substantially constant and / or the same during multiple imprinting steps. The method according to the present invention has the same benefits as elucidated for the for the corresponding system according to the present invention.

[0024] Preferred embodiments of the present invention are set out in the following non- limitative clauses. 1. System for imprinting, in particular nanoimprinting, comprising:

[0025] - at least one substantially flexible stamp configured for imprinting, in particular nanoimprinting;

[0026] - at least one roller configured for exerting pressure onto at least one substantially flexible stamp and / or onto at least one substrate which is to be imprinted;

[0027] - at least one stage configured for providing support for at least one substrate during imprinting; and

[0028] - at least one frame; wherein at least one roller is connected or connectable to at least one frame via at least one air bearing.

[0029] 2. System according to clause 1 , wherein at least one roller is connected or connectable to at least one frame via at least two air bearings.

[0030] 3. System according to clause 1 or clause 2, wherein each distal end of at least one roller is connected or connectable to at least one frame via at least one air bearing.

[0031] 4. System according to any of the previous clauses, wherein at least one roller comprises a shaft and wherein said shaft is connected or connectable to at least one frame via at least one air bearing.

[0032] 5. System according to any of the previous clauses, comprising at least one actuator which is configured for controlling the position and / or pressure of at least one roller and / or at least one flexible stamp.

[0033] 6. System according to any of the previous clauses, comprising at least one actuator configured to apply pressure to at least one air bearing, preferably at least two actuators wherein each actuator is configured to apply pressure to at least one air bearing. 7. System according to any of the previous clauses, wherein at least one actuator is a spring loaded actuator and / or wherein at least one actuator is a pneumatic actuator.

[0034] 8. System according to any of clauses 5 to 7, wherein at least one actuator is configured for operating in two modes and switching between these two modes within a single cycle.

[0035] 9. System according to any of clauses 5 to 8, wherein at least one actuator is configured for following a predetermined position profile.

[0036] 10. System according to any of the previous clauses, wherein at least one roller and at least one stage are mutually displaceable in an imprint direction in particular such that imprinting is facilitated.

[0037] 11 . System according to any of the previous clauses, comprising multiple rollers configured for exerting pressure onto at least one substantially flexible stamp and / or at least one substrate which is to be imprinted, wherein at least two rollers are connected or connectable to at least one frame via at least one air bearing.

[0038] 12. System according to any of the previous clauses, comprising multiple rollers configured for exerting pressure onto at least one substantially flexible stamp and / or at least one substrate which is to be imprinted, wherein at least one roller is connected or connectable to at least one frame via at least one further type of bearing.

[0039] 13. System according to any of the previous clauses, wherein at least one stage is connected or connectable to at least one frame.

[0040] 14. System according to any of the previous clauses, wherein the system is configured for roll-to-plate imprinting, in particular roll-to-plate nanoimprinting.

[0041] 15. System according to any of the previous clauses, wherein at least one substantially flexible stamp comprises at least one textured area. 16. System according to any of the previous clauses, comprising at least one heater for heating and / or cooling of at least part of at least one roller.

[0042] 17. System according to any of the previous clauses, wherein at least one connector comprises at least one adjusting element configured for adjusting the position of at least one substantially flexible stamp with respect to at least one stage.

[0043] 18. System according to any of the previous clauses, comprising at least one tension sensor, at least one temperature sensor and / or at least one position sensor.

[0044] 19. Method for imprinting, in particular nanoimprinting, making use of at least one system according to any of the previous clauses, wherein at least one roller is rotated and / or axially displaced in a frictionless manner during imprinting.

[0045] The invention will be further elucidated by means of non-limiting exemplary embodiments illustrated in the following figures, in which:

[0046] - figure 1 shows a first possible embodiment of a system according to the present invention;

[0047] - figures 2a-2d show a second possible embodiment of a system according to the present invention; and

[0048] - figures 3a-3c show further possible embodiments of a system according to the present invention.

[0049] Within these figures, similar reference numbers correspond to similar or equivalent elements or features.

[0050] Figure 1 shows a first possible embodiment of a system 100 according to the present invention. The system 100 is configured for imprinting, in particular nanoimprinting and comprises optionally a substantially flexible stamp 101 configured for imprinting, in particular nanoimprinting, a roller 102 configured for exerting pressure onto at least one substantially flexible stamp 101 and / or onto a substrate 105 which is to be imprinted. The system 100 further comprises a stage 103 configured for providing support for the substrate 105 during imprinting and a frame 104. The roller 102 is connected, or connectable, to the frame 104 via air bearings 106. In the shown embodiment, the system 100 comprises two air bearings 106. Each air bearing 106 is connected to a distal end of the roller 102. The roller 102 comprises a shaft S and each air bearing 106 is aligned with the shaft S of the roller 102. The figure shows that the roller 102 can be freely moved within the system 100, both in axial direction A and rotational direction R. The system 100 further comprises two actuators 107, which are configured to apply pressure to air bearings 106. A first actuator 107 is configured to apply pressure to a first air bearing 106 at a first distal end of the roller 102 and a second actuator 107 is configured to apply pressure to a second air bearing 106 at a second distal end of the roller 102. The first and second actuators 107 are thereby in particular configured to apply pressure to the shaft S of the roller 102 via each air bearing 106. This will results in that the roller 102 is able to move axially in direction A whilst the actuators 107 maintain their position. The actuators 107 as shown are spring loaded actuators.

[0051] Figures 2a-2d shows a second possible embodiment of a system 200 according to the present invention. Figures 2a and 2c show a side view, whereas figures 2b and 2d shows a top view. More in particular, figures 2a and 2b shows the same initial configuration at the start of the imprint process, and figures 2c and 2d show the final configuration at the end of the imprint process. Each figure shows a system 200 comprising a substantially flexible stamp 201 configured for imprinting, in particular nanoimprinting, a roller 202 configured for exerting pressure onto at least one substantially flexible stamp 201 and / or onto a substrate 205 which is to be imprinted. The system 200 further comprises a stage 203 configured for providing support for the substrate 205 during imprinting. The roller 202 is connected, or connectable, to a frame via air bearings 206. In the shown embodiment, the system 200 comprises two air bearings 206 which are connected to the roller 202 via the shaft S thereof. The frame is not shown in the present figures, but can be configured equivalent to the embodiment as shown in figure 1. The embodiment as depicted in figures 2a-2d shows a single roller 202 and a stage 203 which is displaced with respect to the roller 202 during the imprinting process. The stage 203 is in particular configured to move in the imprint direction I, or alternatively the roller 202 is displaced with respect to the stage 203. During the imprinting process, the structure of the flexible stamp 201 is pressed onto the substrate 205 which is to be imprinted. The figures show that lateral movement of the roller 202 in direction A is enabled due to the presence of the air bearings 206. Hence, the system 200 and method according to the present invention enable lateral motion of the roller 202 and / or the substantially flexible stamp 201 during the imprint cycle.

[0052] Figures 3a-3c shows further possible embodiments of a system 300 according to the present invention. Each figure shows part the system 300, in particular a distal end of the roller 302. The system 300 is configured for imprinting, in particular nanoimprinting and comprises optionally a substantially flexible stamp 301 configured for imprinting, in particular nanoimprinting, a roller 302 configured for exerting pressure onto at least one substantially flexible stamp 301 and / or onto a substrate 305 which is to be imprinted. Each system 300 further comprises a stage 303 configured for providing support for the substrate 305 during imprinting. Each roller 302 is connected, or connectable, to a frame (not shown) via air bearings 306. The air bearing 306 is connected to a distal end of the roller 302, and in particular via the shaft S of the roller 302. The air bearings 306 are aligned with the shaft S of the roller 302. Each figure 3a-3c further shows the presence of an actuator 307a, 307b, 307c. Each actuator 307a, 307b, 307c is configured for controlling the position and / or pressure of roller 302 and / or the flexible stamp 301. In the shown embodiments, the actuators 307a, 307b, 307c are servo motor M controlled actuators 307a, 307b, 307c.

[0053] Figure 3a shows an embodiment wherein the actuator 307a is a spring loaded actuator 307a. The spring element 317 of the actuator 307a is enclosed between the servo motor M and the air bearing 306. Pressure and / or position control of the roller 302 and / or the flexible stamp 301 can be achieved via determining and / or controlling the position x1 of the servo motor M of the actuator 307a, the pressure of at least one spring element 317 and / or the position x2 of the roller 302.

[0054] Figure 3b shows an embodiment which also uses a spring loaded actuator 307b. The spring element 317 of the actuator 307b is enclosed between the servo motor M and the air bearing 306. Additionally, the system 300 comprises a pressure sensor 320. The pressure sensor 320 is configured to measure a pressure, strain, force and / or tension of the roller for example during imprinting. It is conceivable that the pressure sensor 320 comprises a load cell. Pressure and / or position control of the roller 302 and / or the flexible stamp 301 can thus be achieved via determining and / or controlling the position x1 of the servo motor M of the actuator 307a, the pressure determined by at least one pressure sensor 320 and / or the position x2 of the roller 302.

[0055] Figure 3c shows yet a further embodiment wherein a pneumatic actuator 307c is applied. The pneumatic element 327 of the actuator 307c is enclosed between the servo motor M and the air bearing 306. Pressure and / or position control of the roller 302 and / or the flexible stamp 301 can be achieved via determining and / or controlling the position x1 of the servo motor M of the actuator 307a, the pneumatic pressure of the pneumatic element 327 and / or the position x2 of the roller 302.

[0056] It will be clear that the invention is not limited to the exemplary embodiments which are illustrated and described here, but that countless variants are possible within the framework of the attached claims, which will be obvious to the person skilled in the art. In this case, it is conceivable for different inventive concepts and / or technical measures of the above-described variant embodiments to be completely or partly combined without departing from the inventive idea described in the attached claims.

[0057] The verb 'comprise' and its conjugations as used in this patent document are understood to mean not only 'comprise', but to also include the expressions 'contain', 'substantially contain', 'formed by' and conjugations thereof.

Claims

Claims1. System for imprinting, in particular nanoimprinting, comprising:- at least one substantially flexible stamp configured for imprinting, in particular nanoimprinting;- at least one roller configured for exerting pressure onto at least one substantially flexible stamp;- at least one stage configured for providing support for at least one substrate during imprinting; and- at least one frame; wherein at least one roller is connected or connectable to at least one frame via at least one air bearing.

2. System according to claim 1 , wherein at least one roller is configured for exerting pressure onto at least one substrate which is to be imprinted.

3. System according to claim 1 or claim 2, wherein at least one air bearing is configured for axially and / or rotary and / or radially moving the at least one roller with respect to at least one frame and / or at least one stage.

4. System according to any of the previous claims, wherein at least one roller is connected or connectable to at least one frame via at least two air bearings.

5. System according to any of the previous claims, wherein each distal end of at least one roller is connected or connectable to at least one frame via at least one air bearing.

6. System according to any of the previous claims, wherein at least one roller comprises a shaft and wherein said shaft is connected or connectable to at least one frame via at least one air bearing.

7. System according to any of the previous claims, comprising at least one actuator which is configured for controlling the position and / or pressure of at least one roller and / or at least one flexible stamp.

8. System according to any of the previous claims, comprising at least one actuator configured to apply a force, in particular a pressure, to at least one air bearing, preferably at least two actuators wherein each actuator is configured to apply a force, in particular a pressure, to at least one air bearing.

9. System according to any of the previous claims, wherein at least one actuator is a spring loaded actuator and / or wherein at least one actuator is a pneumatic actuator.

10. System according to any of claims 7 to 9, wherein at least one actuator is configured for operating in two modes and switching between these two modes within a single cycle.11 . System according to any of claims 7 to 10, wherein at least one actuator is configured for following a predetermined position profile.

12. System according to any of the claims 5 to 11 , wherein at least one air bearing is positioned in line with at least part of at least one actuator and / or with at least part of at least one roller, in particular a shaft of said roller.

13. System according to any of the previous claims, wherein at least one roller and at least one stage are mutually displaceable in an imprint direction in particular such that imprinting is facilitated.

14. System according to any of the previous claims, comprising multiple rollers configured for exerting pressure onto at least one substantially flexible stamp and / or at least one substrate which is to be imprinted, wherein at least two rollers are connected or connectable to at least one frame via at least one air bearing.

15. System according to any of the previous claims, comprising multiple rollers configured for exerting pressure onto at least one substantially flexible stamp and / or at least one substrate which is to be imprinted, wherein at least one roller is connected or connectable to at least one frame via at least one further type of bearing.

16. System according to any of the previous claims, wherein at least one stage is connected or connectable to at least one frame.

17. System according to any of the previous claims, wherein the system is configured for roll-to-plate imprinting, in particular roll-to-plate nanoimprinting.

18. System according to any of the previous claims, comprising at least one resin applicator for applying at least one resin, in particular at least one curable resin, more in particular at least one crosslinkable resin, to at least one substate and / or at least one flexible stamp.

19. System according to any of the previous claims, wherein at least one substantially flexible stamp comprises at least one textured area.

20. System according to any of the previous claims, comprising at least one heater for heating and / or cooling of at least part of at least one roller.21 . System according to any of the previous claims, wherein at least one connector comprises at least one adjusting element configured for adjusting the position of at least one substantially flexible stamp with respect to at least one stage.

22. System according to any of the previous claims, comprising at least one tension sensor, at least one temperature sensor and / or at least one position sensor.

23. Method for imprinting, in particular nanoimprinting, making use of at least one system according to any of the previous claims, wherein at least one roller is axially displaced in a frictionless manner during imprinting.

24. Method according to claim 23, wherein at least one roller is rotated in a frictionless manner during imprinting.

25. Method according to claim 23 or claim 24, wherein at least during imprinting the thermal conditions of the system are substantially constant and / or at predetermined conditions.

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