Method, device and soft stamp for nanoimprinting

Abstract

The invention relates to a method and a device for imprinting a substrate by means of a soft stamp. The substrate is aligned with the soft stamp in a state of alignment in which a force acts on the soft stamp in order to produce the state of alignment.

Description

[0001] Description

[0002] Process, device and soft stamp for nanoembossing

[0003] The present invention relates to a method and a device for embossing, in particular nanoembossing, substrates with a soft stamp and a soft stamp holder.

[0004] Stamping technology using hard and soft stamps is familiar to those skilled in the semiconductor industry. In the prior art, micro and / or nanostructures are produced either photolithographically and / or with the help of imprint lithography. Imprint lithography is a process in which micro- and / or nanometer-sized structures are embossed into a material using a stamp. The material is an embossing material applied to a substrate. Such imprinting processes have become increasingly important in recent years because they are faster, more effective, and more cost-effective than many photolithographic processes. Furthermore, it has been shown that the resolution achievable using imprint lithography processes is in no way inferior to that which can be achieved with photolithography. In some cases, such as in the so-calledWith “first print” a better resolution can be achieved with imprint lithography than with conventional lithography.

[0005] Most designs of known devices for imprint lithography are built into so-called mask aligners or designed as stand-alone systems, which, however, are usually unable to process substrates larger than 300 mm. Aligners are particularly suitable for special imprint systems, as they are already widely used in the semiconductor industry for photolithography. This makes it expedient for suppliers to offer extensions and attachments that build on or expand on already known mask aligner technology. The main advantage of mask aligners is that in most cases they already have optical systems, in particular lamp housings, for illuminating the substrates, and thus the embossed materials, in particular over the entire area.

[0006] In addition to modified or enhanced mask aligners, there are also dedicated imprinting systems built for specific applications. These systems are typically alignment systems capable of aligning a stamp to the substrate with high precision. Furthermore, these systems have the ability to generate a vacuum, special dispensing systems, etc. Such imprinting systems rarely offer the capability of imprinting an imprinting material on a substrate larger than 300 mm.

[0007] Imprinting systems exist that enable the production of structures for display devices, i.e. displays, especially curved or flat screens.

[0008] There are five known techniques of imprint lithography:

[0009] • Micro- and / or nanocontact printing (p / nCP)

[0010] • Replica casting (SEM)

[0011] • Micro-transfer molding (pTM) or nanoimprint lithographic (NIL),

[0012] • Microforming in capillaries (MIMIC)

[0013] • solvent-assisted micromolding (SAMIM).

[0014] Imprint stamps are generally divided into two categories. Hard stamps (made of metal, ceramic materials, or bulky glass or plastic) and soft stamps (made of polymers such as silicones, etc.) can be used. All imprint stamps have a textured stamp surface, which typically contains the negative of the pattern to be created and is molded into the embossing compound applied to a substrate to be embossed.

[0015] Soft stamps are produced as negatives of a master stamp. Master stamps are stamps used to create the original soft stamp. In other words, master stamps are templates for replication. The master stamp is either a hard stamp made of metal, glass, especially quartz glass, plastic, or ceramic, which is manufactured once through complex processing, or a soft stamp to be molded, especially a soft stamp with an elastic, stiffened carrier.

[0016] Any number of soft stamps can then be produced from the master stamp. The soft stamps enable conformal, uniform contact over large surfaces. Both the master stamp and the soft stamp, as well as the soft stamp and the embossed surface of the substrate, can be separated from each other without damage. This separability is a result of the low surface energy of a soft stamp, which is achieved through functionalization, particularly coating.

[0017] Soft stamps are easier to separate from the substrate than hard stamps. For the automated implementation of soft lithographic processes, it is preferably necessary to support the soft stamp with a carrier. Currently, glass carrier substrates of various thicknesses are widely used. However, the use of thick glass substrates causes the soft stamp to lose at least some of its flexibility. The glass carriers are sufficiently thin glass carriers, which provide the necessary stability for the soft stamp, but are flexible enough to achieve a given flexibility. It is also possible to use a polymer film and / or a deformable, thin glass plate, even as a composite material, as a carrier to enable and facilitate the handling of the stamp. A soft stamp reinforced with a carrier has increased strength and rigidity as well as increased dimensional accuracy compared to non-reinforced soft stamps.

[0018] Other designs of soft stamps are manufactured as layered systems made of elastomer or polymer. Mechanical properties such as stability, elasticity, flatness, and roughness can be significantly influenced by the substrate. The structures of the soft stamp are created from the soft stamp material, particularly by molding the master stamp.

[0019] Throughout this text, stiffness will primarily, but not exclusively, refer to flexural stiffness. Stiffness is a technical parameter that depends on the material and geometry.

[0020] A soft stamp, especially one stiffened with a carrier, has the necessary rigidity to align it with the substrate before embossing. However, the stiffness of the soft stamp is disadvantageous during embossing, since sufficient osculation cannot be achieved, particularly when embossing non-planar substrates. Increased stiffness of the soft stamp leads to increased separation forces, which arise between the soft stamp and the embossed substrate when the soft stamp is separated from the substrate. The increased force can damage both the embossed structures of the substrate and the soft stamp, leading to defects in the soft stamp and / or the embossed structures of the substrate.

[0021] The soft stamp release must be precisely controlled so that the embossed soft stamp structure and the soft stamp are not damaged during demolding from the substrate.

[0022] When molding a soft stamp, deformations due to material stress can distort the true dimensions of the stamped soft stamp structures, making the dimensional accuracy and separability of the stamped soft stamp structures a core task of every stamping process. In particular, a change in the length of the soft stamp without additional compensation changes the material stress, which also results in a change in the stamp's dimensional accuracy.

[0023] The state of the art for the micro- and / or nanostructuring of surfaces primarily includes photolithography and various embossing techniques. These embossing techniques use either hard or soft stamps. Recently, embossing lithography techniques have become particularly popular, displacing traditional photolithography techniques. Among embossing lithography techniques, the use of so-called soft stamps is becoming increasingly popular. The reasons for this are the ease of production of the stamps, efficient embossing processes, very good surface properties of the respective stamp materials, low costs, reproducibility of the embossed product and, above all, the possibility of elastic deformation of the stamp during embossing and demolding. In soft lithography, a stamp made of an elastomer with a micro- or soft stamping layer is used.nanostructured surface to produce structures with characteristic feature sizes in the range from less than 1 nm to 1000 pm.

[0024] Besides the advantages of imprint lithography with a soft stamp, there is the disadvantage of this technology, which arises from the elasticity of the stamp, meaning that the dimensional accuracy of the stamp cannot always be guaranteed. This leads to inaccuracies and distortions of the imaged, embossed structures compared to the imprinted structures of the stamp.

[0025] Rigid imprint stamps are difficult to form on uneven embossed surfaces. Soft, flexible imprint stamps are difficult to align with the embossed surface.

[0026] It is therefore the object of the invention to at least partially eliminate, and in particular completely eliminate, the disadvantages cited in the prior art. In particular, it is an object of the invention to provide an improved method and device for embossing. Furthermore, it is an object of the invention to provide an improved soft stamp holder with which more precise alignment can be achieved.

[0027] The present object is achieved by the features of the independent claims. Advantageous developments of the invention are specified in the dependent claims. The scope of the invention also includes all combinations of at least two features specified in the description, the claims, and / or the drawings. For specified value ranges, values ​​within the specified limits are also considered to be disclosed as limit values ​​and can be claimed in any combination.

[0028] Accordingly, the invention relates to a soft stamp holder for receiving a soft stamp for embossing substrates, at least comprising receiving means for receiving the soft stamp so that the soft stamp can be held in a flat surface, at least one movable soft stamp holder element for applying a force to the soft stamp, wherein the at least one movable soft stamp holder element is designed such that the force can be applied to the soft stamp in a defined direction of action to the plane so that the soft stamp can be transferred into an alignment state.

[0029] In other words, a punch holder is provided which enables more precise alignment in an alignment state by applying force to the soft punch. It has surprisingly been found that by applying force to the soft punch during alignment before embossing, an alignment state can be set which enables reproducible and precise alignment. The application of force changes, in particular, the stiffness of the soft punch. In addition, the soft punch can be slightly deformed or bent. The shape or deflection thus set is reproducible, so that advantageous alignment can be achieved in this alignment state. By moving back at least one soft punch holder element, the soft punch can also be converted back into a flexible and non-stiffened state, so that the soft punch thus released can optimally transfer the embossed structures.

[0030] The support means can be, for example, a frame for clamping the soft stamp or a support surface. The soft stamp is arranged essentially on a flat surface, so that the direction of action of the force is along the preferably flat soft stamp. In the alignment state thus created, precise positioning of the soft stamp holder of the flexible soft stamp can advantageously be achieved.

[0031] Thus, the soft stamp is preferably subjected to a force in an outer region (periphery) by the at least one movable soft stamp holder element. The force is applied, for example, laterally to the soft stamp. In this way, the rigidity and / or shape of the soft stamp can be advantageously changed, allowing for more precise and simple alignment with the soft stamp holder. The movable soft stamp holder elements are preferably arranged regularly along a circumference of the receiving surface for the soft stamp.

[0032] In a preferred embodiment of the soft stamp holder, the force is provided to be a compressive force. In other words, a compressive force is applied to or at the soft stamp, so that the compressive force acts on the soft stamp. The soft stamp can be slightly deformed or compressed. In this way, an alignment of the soft stamp in a predetermined shape can advantageously be achieved. The soft stamp can be bent or curved. The rigidity or flexural rigidity of the soft stamp can advantageously be increased and advantageously adjusted by, in particular, pressing laterally towards a center of the soft stamp or soft stamp holder. In a preferred embodiment of the soft stamp holder, the compressive force can be applied laterally to the outer edge of the soft stamp.In other words, pressure is applied to the outer edge of the soft stamp to adjust the alignment. The outer edge can be held in place by a frame or clamps, for example. This method has proven particularly advantageous for adjusting the alignment easily and reproducibly.

[0033] In a preferred embodiment of the soft stamp holder, the compressive force can be applied toward a center point of the soft stamp holder. In this way, the force can advantageously be applied toward the center or the center point. Reinforcing elements can be formed in the soft stamp, through which the force is introduced into the soft stamp. In this way, the soft stamp can be compressed or stiffened particularly evenly and in a predetermined manner.

[0034] In a preferred embodiment of the soft stamp holder, the soft stamp holder has at least two movable soft stamp holder elements, wherein the at least two soft stamp holder elements are arranged on opposite sides of the soft stamp holder, such that the respective forces can be applied in the direction of the center point. In other words, the soft stamp is pressed together by several soft stamp holder elements in the direction of the center point, such that the alignment state can be adjusted. The individual forces are preferably of equal magnitude. In this way, a particularly uniform and targeted stiffening of the soft stamp is possible. Preferably, several movable soft stamp holder elements are arranged along the outer edge of the soft stamp, lying opposite one another with respect to the center point or the center, in particular at regular intervals along a circumference of the soft stamp.This allows the force to be applied evenly to the soft stamp.

[0035] In a preferred embodiment of the soft stamp holder, the receiving means are designed as clamps. The soft stamp is thus held at the edge by several clamps or a frame with a clamping function. The movable soft stamp holder elements can also be designed as clamps. Furthermore, the receiving means can be formed by movable and immovable soft stamp holder elements. Furthermore, the soft stamp holder elements can form the frame or a receiving surface. The clamping function can also be formed by a combination of movable and immovable soft stamp holder elements. In this way, the alignment state with increased rigidity can be achieved particularly gently.

[0036] In a preferred embodiment of the soft punch holder, the soft punch holder is configured for transfer to the alignment state such that the magnitude of the force acting on the soft punch is increased in a controlled manner until deformation of the soft punch occurs. In other words, the force is increased until deformation or compression of the soft punch is detected or registered. The increase can, for example, be dependent on a measured value. As soon as curvature or deflection occurs, in particular in the center of the soft punch, the force is no longer increased. The alignment state achieved in this way establishes the stiffened state of the soft punch with increased flexural rigidity, in which alignment can be carried out particularly precisely.

[0037] In a preferred embodiment of the soft punch holder, the soft punch holder is designed such that the magnitude of the force acting on the soft punch can be adjusted such that, in the aligned state, the soft punch has increased flexural rigidity. In other words, the flexural rigidity or stiffness of the soft punch can be advantageously changed or adjusted for alignment by the force. In addition to the flexural rigidity, the storage conditions and the length of a component being bent also determine how strongly its deflection can occur. The deflection is referred to as curvature and is proportional to the acting bending moment. The curvature is also inversely proportional to the flexural rigidity. The stiffness, on the other hand, depends on the elasticity of the material and the shape and size of the cross-sectional area.In this respect, the corresponding values ​​are determined individually for a soft stamp so that the flexural rigidity can be advantageously adjusted in a targeted manner.

[0038] In a preferred embodiment of the soft stamp holder, the soft stamp holder is designed such that the magnitude of the force acting on the soft stamp is controllable such that in the aligned state the soft stamp is deformed, in particular compressed, by less than 1 mm, preferably less than 100 micrometers, particularly preferably less than 10 micrometers, optimally less than 1 micrometer. In other words, deformation or compression of the soft stamp is deliberately kept within a certain range. This range has proven to be particularly advantageous for being able to align the soft stamp precisely. In a preferred embodiment of the soft stamp holder, the force is between 0.1 N and 100 kN, preferably between 1 N and 500 N, particularly preferably between 10 N and 300 N, optimally between 100 N and 250 N.The force provided by a movable soft stamp holder element is therefore certain values ​​which have proven to be optimal for transferring the soft stamp into the desired alignment state.

[0039] In a preferred embodiment of the soft stamp holder, the soft stamp is subjected to an electric and / or magnetic field, so that the stiffness of the soft stamp is specifically changed. In other words, the modulus of elasticity can be changed by an external field, thus enabling the soft stamp to be more effectively switched to the stiff alignment state.

[0040] In a preferred embodiment of the soft stamp, ideally only the elastic modulus and thus the stiffness of the soft stamp is changed, allowing for more precise alignment with the soft stamp holder. The change in the elastic modulus is preferably achieved through electric and / or magnetic fields.

[0041] In less preferred technical realizations of the embodiment of the soft stamp, the soft stamp is minimally deformed in order to bring about the change in stiffness. In particular, the soft stamp is curved away from the plane that spans the embossed side, so that no contact is made with the substrate in the aligned state. In a preferred embodiment of the soft stamp, the soft stamp contains polymers and / or thin glasses and / or metal foils and / or thin semiconductor substrates. The respective thickness of the soft stamp depends on the soft stamp material. For polymers, the thickness is less than 1 mm, preferably less than 500 micrometers, particularly preferably less than 100 micrometers, and optimally less than 10 micrometers. For soft stamps made of thin glass, soft stamp thicknesses of less than 30 micrometers are preferably used.

[0042] Furthermore, the invention relates to a device for embossing a substrate, at least comprising the soft stamp holder for receiving the soft stamp in a flat surface, a substrate holder for receiving the substrate, and alignment means for aligning the substrate and the soft stamp with respect to one another. The at least one movable soft stamp holder element is configured such that, upon application of the force, the soft stamp can be transferred into an aligned state, and the alignment means are configured such that the alignment can be carried out in the aligned state. In other words, the advantageous soft stamp holder is provided in an embossing device, so that particularly precise alignment and thus embossing can be carried out.In particular, the soft stamp to be used has a plurality of alignment marks which are aligned in the alignment state relative to the substrate or to further alignment marks on the substrate.

[0043] Furthermore, the invention relates to a method for embossing a substrate with a soft stamp, comprising the following steps, in particular in the following order: i) providing a soft stamp, wherein the soft stamp is held by a soft stamp holder, ii) applying a force to the soft stamp to transfer the soft stamp into an aligned state, iii) aligning the soft stamp in the aligned state with the substrate, iv) removing the force acting on the soft stamp, v) embossing the substrate with the soft stamp. In the method, the soft stamp is particularly preferably provided in the device.

[0044] In particular, the soft stamp is held in such a way that the force acts along the flat or flat soft stamp. In the alignment state, the externally applied force increases the stiffness of the soft stamp or forces it into an alignment shape. In this way, a specific and predetermined position of the soft stamp can be aligned with the substrate during alignment, thus increasing the stamping accuracy.

[0045] In a preferred embodiment of the method, the force is a compressive force, and the soft die is compressed in the alignment state. In other words, the soft die is compressed in such a way that the rigid and advantageous alignment state is achieved.

[0046] In a preferred embodiment of the method, after embossing, the method further comprises the following step: vii) applying a separation force to the soft stamp in the opposite direction of the force for transferring it into the alignment state. In this way, a force for easily separating the soft stamp from the substrate can advantageously be applied to the soft stamp via the movable soft stamp holder elements.

[0047] In a preferred embodiment of the method, the soft die has a plurality of force-absorbing points so that the force acts evenly on the soft die. The contact points can be formed, for example, by reinforcing elements on the edge of the soft die or by eyelets formed in the soft die. This allows for a particularly gentle application of the force.

[0048] In addition, the force acts particularly evenly on the soft stamp, so that an advantageous optimal alignment state and thus precise alignment is achieved.

[0049] In a preferred embodiment of the method, after alignment in step iii), a soft stamp embossing surface and a substrate surface facing the soft stamp embossing surface are each held in an aligned position, so that embossing occurs by approaching the soft stamp and the substrate. The soft stamp surface has the embossed structures. In the aligned state, the substrate and the soft stamp are aligned with each other. After alignment, the surfaces to be contacted are thus already optimally aligned. Embossing then occurs only by continuously bringing the soft stamp and the substrate closer together. Thus, only a vertical movement of the substrate holder and / or the soft stamp holder is necessary for embossing.After the force is switched off or the soft stamp holder elements are moved back, the stiffness of the soft stamp is advantageously eliminated, so that particularly simple and precise stamping can take place.

[0050] In a preferred embodiment of the method, when applying the force to transfer to the alignment state in step ii), the force is continuously increased until deformation of the soft punch occurs. In other words, the force is only increased, preferably continuously increased, until deformation or curvature would occur. This does not refer to the minimal deformation at the edge caused by the movable soft punch holder elements. Rather, a deformation or curvature in the center of the soft punch is analyzed, and an increase in the force is stopped accordingly. The alignment state set in this way thus advantageously provides the soft punch in a rigid state before deflection or curvature.

[0051] Furthermore, the method preferably comprises at least one of the following steps: vi) curing the embossed substrate, vii) reversing the force acting on the soft stamp to separate the soft stamp and the embossed substrate from one another, iix) separating the soft stamp and the embossed substrate from one another. In the method, the soft stamp is particularly preferably provided in the device. In particular, the soft stamp is held such that the force acts along the flat soft stamp. In the aligned state, the externally applied force increases the stiffness of the soft stamp or brings it into the aligned state. In this way, a specific and predetermined position of the soft stamp can be aligned to the substrate during alignment, so that the embossing accuracy is increased.

[0052] In a preferred embodiment of the method, it is provided that the soft stamp is at least partially permeable to UV radiation, so that curing can be carried out through the soft stamp during embossing.

[0053] A particularly important aspect of the present invention is that the targeted modification of the stiffness or flexural rigidity of the soft stamp is used for imprinting. In the tensioned or aligned state, the soft stamp is stiff and can be precisely aligned with the imprinting substrate. In the switched, relaxed state, the soft stamp is correspondingly flexible, allowing a good conformation to the substrate during imprinting. The imprint stamp is rigid during alignment and flexible and flexible during imprinting.

[0054] The soft die can change, in particular increase, its flexural rigidity when subjected to an external force and / or an external field. If no external force acts on the soft die, its flexural rigidity is low.

[0055] The soft punch can preferably change its shape, particularly locally, in a reproducible manner with the change in its flexural rigidity, so that the soft punch can always be aligned with the same state and / or shape.

[0056] The soft stamp has, in particular, a full-circumference edge that can be used for handling and an embossing zone that contains the embossed pattern to be molded. The soft stamp can be reinforced with stiffening elements for handling, at least along one section of the edge.

[0057] In one embodiment of the soft punch, two opposing edges, which are in particular parallel to each other, are used for the introduction of the external force, so that the soft punch can assume a reproducible, non-planar, curved shape with increased flexural rigidity, in particular for handling and alignment.

[0058] In another embodiment of the soft stamp, the edge can be held at one edge between two supports with a clamp and the soft stamp can be deformed locally so that the flexural rigidity is increased globally.

[0059] In a further embodiment of the soft stamp, the soft stamp can be brought into the alignment state by applying pressure and / or vacuum from the soft stamp side facing away from the embossing side, which reversibly solidifies the soft stamp. In other words, instead of parallel to the plane, the soft stamp is pressed or pulled from above perpendicular to the plane. In particular, after a vacuum is switched off, for example, the soft stamp is returned to the elastic embossing shape. In other words, the switchable soft stamp is brought into the rigid alignment state by the action of a fluid, a liquid, a gas, or a vacuum. The return to the soft and elastic embossing state occurs when the effect of the fluid is eliminated and / or when ambient pressure is reached.

[0060] In a further embodiment of the soft stamp, the soft stamp can be reversibly modified by the action of an external field, in particular the Young's modulus. In particular, the soft stamp can be switched to the rigid alignment state using an electric and / or magnetic field. After the field is removed, the soft stamp returns to the elastic embossed state, particularly within a few seconds.

[0061] The substrate holder of the device has fixing devices. The fixing devices are used to hold the substrates. The fixing devices can be

[0062] 1. Mechanical fixations, especially

[0063] 1. 1. Terminals

[0064] 2. Vacuum fixations, especially with

[0065] 2. 1. individually controllable vacuum tracks

[0066] 2.2. interconnected vacuum tracks

[0067] 3. Electrical fixations, especially

[0068] 3. 1. Electrostatic fixations

[0069] 4. Magnetic fixations

[0070] 5. Adhesive fixations, especially

[0071] 6. Gel-Pak fixations 7. Fixations with adhesive, particularly controllable, surfaces.

[0072] The fixations are, in particular, electronically controllable. Vacuum fixation is the preferred fixation type. Vacuum fixation preferably consists of several vacuum tracks that emerge from the surface of the substrate holder. The vacuum tracks are preferably individually controllable. In a technically more feasible application, several vacuum tracks are combined into vacuum track segments that can be individually controlled and thus evacuated or flooded.

[0073] However, each vacuum segment is independent of the others. This allows for the construction of individually controllable vacuum segments. The vacuum segments are preferably designed in a ring shape. This enables the targeted fixation and / or release of a substrate from the substrate holder.

[0074] The device also comprises, in particular, a punch holder, in particular a soft punch holder, which accommodates a soft punch with variable flexural rigidity. The punch holder can contain the movement and / or alignment means for the punch holder, functionally and / or component-integrated.

[0075] Furthermore, the device preferably comprises movement and / or alignment means for the punch holder, in particular the soft punch holder, with the adjusting elements, actuators for generating force for changing the flexural rigidity of the soft punch.

[0076] In one embodiment of the device, the movement means for the stamp holder can reproducibly compress the soft stamp on opposite sides so that the soft stamp reacts to the external force introduction by changing its flexural rigidity and shape. This enables precise, reproducible alignment of the soft stamp to the substrate. In one embodiment of the device, the movement means for the stamp holder can support the soft stamp at the edge with two spaced-apart pins and can grip and locally deform the soft stamp with a movable pin mounted between the spaced-apart pins, so that the soft stamp is globally stiffened due to the change in flexural rigidity and the soft stamp can be aligned to the substrate with high precision.

[0077] Furthermore, the device comprises movement and / or alignment means for the substrate, such as coarse and / or fine drives.

[0078] Furthermore, the device comprises embossing means for contacting the soft stamp with the substrate to be embossed, which is coated with the embossing compound, in particular pressure means such as rollers, or counterparts of the substrate, or directed nozzles for generating pressure with compressed air or with a deformable balloon filled with a liquid.

[0079] The embossed substrate and the soft stamp can be separated from each other using the device's release agent.

[0080] Advantageously, the device further comprises illumination and / or curing means such as radiation sources and / or heat sources (in particular lamp housings for UV irradiation and / or thermal radiators).

[0081] The movement and / or alignment means of the device are movement devices with drive systems, guide systems, holding devices and measuring systems in order to move, position and align the optical systems as well as the soft stamp and / or substrates.

[0082] The motion devices can generate each movement as a result of individual movements, so that the motion devices can preferably include fast coarse positioning devices that do not meet the accuracy requirements, as well as precise fine positioning devices. A target value of the position to be approached, in particular an alignment mark, is an ideal value. The motion device approaches the ideal value. Reaching a defined range around the ideal value can be understood as reaching the target value.

[0083] A positioning device is understood as a coarse positioning device if the approach and / or repeat accuracy deviates from the target value by more than 0.1%, preferably more than 0.05%, particularly preferably more than 0.01%, based on the entire travel path or rotation range, in the case of rotary drives capable of rotation, a full rotation of 360 degrees.

[0084] For example, a coarse positioning device with a travel distance of more than 600 mm (twice the substrate diameter) results in a positioning accuracy of 600 mm * 0.01%, i.e. more than 60 micrometers as residual uncertainty.

[0085] In other embodiments of coarse positioning, the residual uncertainty of the approach or repeatability accuracy is less than 100 micrometers, preferably less than 50 micrometers, particularly preferably less than 10 micrometers. Thermal disturbances should also be taken into account.

[0086] A coarse positioning device only fulfills the positioning task with sufficient accuracy if the deviation between the actual position actually reached and the target position value lies within the travel range of an associated fine positioning device.

[0087] An alternative coarse positioning device only fulfills the positioning task with sufficient accuracy if the deviation between the actual position actually reached and the setpoint position is within half the travel range of an associated fine positioning device. A positioning device is defined as a fine positioning device if the residual uncertainty of the approach and / or repeat accuracy from the setpoint does not exceed 500 ppb, preferably less than 100 ppb, ideally 1 ppb, based on the entire travel or rotation range.

[0088] Preferably, the device provides an alignment accuracy or a position accuracy with an absolute positioning error of less than 5 micrometers, preferably less than 1 micrometer, particularly preferably less than 100 nm, very particularly preferably less than 10 nm, optimally less than 5 nm, ideally less than 1 nm.

[0089] Preferably, the device achieves a local alignment accuracy or a local position accuracy, which reduces the local distortions and / or deformations measured on the embossed substrate to less than 5 micrometers, preferably less than 1 micrometer, particularly preferably less than 100 nm, very particularly preferably less than 10 nm, optimally less than 1 nm, ideally less than 0.1 nm.

[0090] The present device and associated methods comprise at least one positioning device of the highest accuracy and reproducibility. A concept of mutual error correction can be used to ensure the quality of the alignment of the substrate to the soft stamp. Thus, a known offset (twisting and / or displacement) of a substrate and the corresponding positioning device can be increased by adjusting and correcting the position of the soft stamp, particularly in the stiffened state, using correction values ​​or correction vectors. The extent and type of twisting and / or displacement determines how the control system uses coarse and fine positioning, or only coarse or only fine positioning, to correct the error.In one embodiment of the device, the substrate and / or the soft stamp can be deformed and / or tempered using mechanical actuators and / or piezo elements to minimize offset during embossing. The targeted change in temperature changes the shape and size of at least one of the substrate and / or the soft stamp. The targeted change in the shape of the substrate holder changes the shape of the substrate attached to it.

[0091] In the following text, positioning devices (coarse or fine or compound positioning devices) and alignment means are used as synonyms.

[0092] The alignment of the soft stamp and the substrate can be performed in all six degrees of freedom: three translations along the x, y, and z coordinate directions, and three rotations around the coordinate directions. The movements can be performed in any direction and orientation.

[0093] Robots for substrate handling and soft stamp handling are classified as motion devices. The fixtures can be integrated into the motion devices as components or functionally. Furthermore, a device preferably includes control systems and / or evaluation systems, in particular computers, to execute the described steps, in particular motion sequences, embossing and separation, to perform corrections, and to analyze and store the operating states of the device.

[0094] Processes are preferably created as recipes and executed in machine-readable form. Recipes are optimized collections of values ​​for parameters that are functionally or procedurally related. The use of recipes allows for the reproducibility of production processes. Furthermore, according to an advantageous embodiment, a device can include supply, auxiliary, and / or supplementary systems (compressed air, vacuum, electrical energy, fluids such as hydraulics, coolants, heating media, means and / or devices for temperature stabilization, electromagnetic shielding, ionizers and / or deionizers, electrostatic dust traps).

[0095] Furthermore, a device includes frames, cladding, vibration-suppressing or damping or cancelling active or passive subsystems.

[0096] A frame can be understood as a part, in particular made of natural hard stone or mineral casting or spheroidal graphite cast iron or hydraulically bound concrete, which is in particular vibration-damped and / or vibration-insulated and / or installed with vibration damping.

[0097] Furthermore, the device particularly preferably includes at least one measuring system, preferably with measuring units for each movement axis, which can be designed in particular as path measuring systems and / or as angle measuring systems.

[0098] Furthermore, the device preferably includes at least one measuring system, preferably with measuring units for radiation intensity, in particular for the radiation for curing the embossing compound.

[0099] Furthermore, the device preferably includes at least one measuring system for observing and / or controlling the adjustment or alignment marks of the stamp, in particular the soft stamp and / or the substrate.

[0100] Furthermore, the device preferably includes at least one pressure measurement and control system, in particular vacuum and / or overpressure, which measures, records, and controls the pressure on / in the soft stamp during embossing. Furthermore, the device preferably includes at least one measurement system for monitoring the alignment of the soft stamp and the substrate relative to each other.

[0101] Both tactile (i.e., probing) and non-tactile measurement methods can be used. The measurement standard, the unit of measurement, can be a physical object, particularly a scale, or it can be implicit in the measurement process, such as the wavelength of the radiation used.

[0102] To achieve alignment accuracy, at least one measuring system can be selected and used. Measuring systems implement measuring methods. Preferably

[0103] • Inductive methods and / or

[0104] • Capacitive processes and / or

[0105] • Resistive processes and / or

[0106] • Comparison methods, in particular optical image recognition methods,

[0107] Detection of position markers and / or QR codes and / or

[0108] • incremental or absolute methods (in particular with glass standards as scale, or interferometers, in particular laser interferometers, or with magnetic standards) and / or

[0109] • Runtime measurements (Doppler method, time of flight method) or other time recording methods and / or

[0110] • Triangulation methods, especially laser triangulation,

[0111] • Autofocus method and / or

[0112] • Intensity measurement methods such as fiber optic rangefinders can be used. In particular, measured values ​​can be combined and / or referenced and / or correlated with each other, so that a measurement of one alignment mark can be used to determine the position of the related other alignment mark. In particular, the position of the soft stamp can be calculated from the position values ​​of the soft stamp holder and the detected alignment marks and corrected accordingly.

[0113] For position determination, in particular 3D position determination at one point, two points, three points, or any number of points, a first embodiment can utilize optical pattern recognition using camera systems to provide a unique reference of the position and height. The patterns are recorded in a real-time system, in particular continuously during the alignment of the soft stamp and the substrate. The measurement methods listed above can also be used for position determination.

[0114] The movement devices not used for fine adjustment are preferably designed as robotic systems, preferably with incremental displacement sensors. The accuracy of these movement devices for auxiliary movements is preferably decoupled from the accuracy for aligning the soft stamp and the substrate, so that the auxiliary movements are executed with a low repeatability of less than 1 mm, preferably less than 500 micrometers, particularly preferably less than 150 micrometers.

[0115] The accuracy of the movement devices for aligning the device is preferably less than 200 nm, preferably less than 100 nm, particularly preferably less than 50 nm, very particularly preferably less than 20 nm, optimally less than 10 nm, ideally less than 1 nm.

[0116] In particularly preferred embodiments of the device, the error in the alignment accuracy of the device is 20% of the maximum permissible alignment error, particularly preferably 10% of the maximum permissible alignment error, optimally 1%. A preferred exemplary embodiment of the method comprises the following steps, in particular at least performed consecutively and / or simultaneously, in particular with the following sequence:

[0117] First process step: The substrate is loaded onto the substrate holder with a support surface, while the opposite side, the so-called embossing side of the substrate, is coated with the embossing compound and is accordingly prepared for embossing.

[0118] Second process step: The soft stamp is brought close to the alignment position with the soft stamp holder and clamped accordingly.

[0119] Third process step: By means of the clamping, the bending stiffness of the soft punch is changed so that the soft punch is brought into the stiff alignment state by the external force of the clamping.

[0120] Fourth process step: The soft stamp and the substrate are aligned to each other. Alignment can be achieved using alignment marks and / or edges and / or defined embossed structures on the soft stamp. The shape and distortion of the soft stamp are taken into account during alignment.

[0121] Fifth process step: By maintaining and / or correcting the position of the aligned soft punch so that the embossed structures remain at the intended positions or are moved there by the correction, the soft punch is brought into the relaxed, force-free state by eliminating the external force which has increased the flexural rigidity of the soft punch.

[0122] Sixth process step: The soft stamp and the substrate are brought into contact. Seventh process step: The soft stamp is embossed. In particular, the full embossing force can be applied to the soft stamp in the form of a surface force or line force by pressure. A non-structured embossing roller can be used, in particular, to apply the embossing force.

[0123] Eighth process step: The embossing compound is cured by the soft stamp, particularly by means of UV radiation.

[0124] Ninth process step: The soft stamp and the substrate are separated from each other by means of the separating device of the embossing device.

[0125] Tenth process step: The embossed substrate is released from the substrate holder and transported to the tray for embossed substrates.

[0126] To the extent that device features are disclosed here and / or in the subsequent description of the figures, these shall also be deemed to be disclosed as process features, and vice versa. All numerical values ​​and relational specifications (parallelism, congruence, normality, flatness, etc.) in this disclosure are used as terms for quantities subject to tolerances, so that, in particular, the tolerances for non-tolerated linear or angular dimensions according to ISO 2768 as well as the semi-standards relevant to the semiconductor industry (for flatness, waviness, deflection, particle load, etc.) apply, unless the tolerances are explicitly stated.

[0127] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the accompanying drawings. In the drawings, identical components or components with the same function are identified by the same reference numerals. The drawings are to be understood as sketches from which no size relationships or scales can be derived. They show the relationships of the parts to one another, possibly in an exaggerated representation, which is used for illustrative purposes. These show schematically in:

[0128] Fig. la a soft stamp holder with a soft stamp in the relaxed state,

[0129] Fig. 1b the soft stamp holder with a soft stamp in the alignment state with external force,

[0130] Fig 2a another embodiment of the soft stamp holder with a soft stamp in the relaxed state,

[0131] Fig. 2b shows the further embodiment of the soft stamp holder in the alignment state with external force,

[0132] Fig. 2c is a top view of the further embodiment of the soft stamp with an exemplary soft stamp holder element arrangement.

[0133] Fig. 1a shows the parts of an embossing device 1 with the details necessary for understanding. In the embossing device 1, the soft stamp 2 is prepared for embossing, in particular without external constraining forces. The substrate to be embossed, the embossing compound and other parts such as movement devices are not shown. The soft stamp 2 with the switchable stiffness is preferably firmly clamped on one side in the soft stamp holder 3 and 3'. The embodiments of the soft stamp holder 3 and 3' can hold and / or clamp and / or immovably support the soft stamp along at least one surface of the soft stamp 2 or along a line of the soft stamp 2 or at defined points. Immobility of all soft stamp holders means that one soft stamp holder is fixed for the alignment and / or embossing processes.The immobility of a soft stamp holder expressly allows adjustment and / or feed movements or positioning tasks and the fastening of the soft stamp with switchable stiffness 2. In other words, the non-moving soft stamp holders, in particular the soft stamp holders 3 and 3', are not permanently fixed to the frame.

[0134] The soft stamp 2 is preferably held by movable soft stamp holders 4 and 4' at the edge opposite the soft stamp holders 3 and 3'. The movable soft stamp holders 4 and 4' fix the soft stamp 2 along at least one surface or along a line or at defined points. The movable soft stamp holders 4 and 4' apply the external force necessary to change the flexural rigidity of the soft stamp 2 to the soft stamp 2.

[0135] Fig. 1b shows the parts of a device for embossing 1. The soft stamp with switchable stiffness 2 was brought into the stiff state by means of an external force F in a defined direction. For this purpose, the soft stamp 2 is held by the soft stamp holder 3 and 3'. With the movable soft stamp holder 4 and 4', an external force F, in particular a compressive force, is applied to the soft stamp 2 so that the soft stamp 2 is brought into the flexurally stiff state and has sufficient stiffness for handling and alignment with the substrate (not shown). In particular due to the effect of the force F, the movable soft stamp holders 4 and 4' are displaced in one direction, in particular by Ax, so that the soft stamp 2 is brought into the schematically illustrated flexurally stiff alignment state.

[0136] Fig. 2a shows a further embodiment of an embossing device 1' with the relevant parts shown. An embodiment of a soft stamp with switchable rigidity 2' is clamped between at least one soft stamp holder 3" and a movable soft stamp holder 4" so loosely that the soft stamp 2' can be embossed in the flexible state, in particular in the aligned state. The clamping of the soft stamp 2' can be so rigid by means of the soft stamp holders 3" and 4" that the soft stamp 2' can be moved, but at the same time the clamping is carried out with such low forces that the soft stamp is not switched to the rigid state.

[0137] Fig. 2b shows an embodiment of a soft stamp with switchable stiffness 2' in the switched state, cf. Fig. 2a. For this purpose, the soft stamp 2' is deformed between the soft stamp holders 3" and 4", in particular at three points or along three parallel lines, with an external force F to such an extent that the stiffness of the soft stamp is changed to the stiff state. The force F for switching the soft stamp 2' is generated between the soft stamp holders 3" and 4", in particular by a displacement of the movable soft stamp holder 4", in particular by Ay.

[0138] The stiff, switched state of the soft stamp 2' will be used to align the soft stamp to the substrate.

[0139] Fig. 2c shows the embodiment of the soft stamp 2' shown in Figs. 2a and 2b in a top view in a cutaway representation. The soft stamp with switchable stiffness 2' rests on two immovable soft stamp holders 3". The movable soft stamp holder 4" deforms the soft stamp 2' by means of the external force, in particular into the rigid state, so that alignment of the soft stamp is possible. It is advantageous if the alignment markings of the soft stamp 2' (not shown) are located as far as possible from the local deformation, so that the global shape of the soft stamp resembles a plane and thus a simple alignment of the soft stamp 2' can be achieved without any shape correction performed on the computer. List of reference symbols, 1' device for embossing, soft stamp holder, 2' soft stamp, flexible stamp, 3', 3" immovable soft stamp holder element, receiving means,

[0140] Clamps, 4', 4" movable soft stamp holder element

Claims

Patent claims 1) Soft stamp holder for receiving a soft stamp (2, 2') for embossing substrates, at least comprising: - receiving means (3, 3', 3") for receiving the soft stamp (2, 2'), so that the soft stamp (2, 2') can be held in a flat surface, - at least one movable soft stamp holder element (4, 4', 4") for applying a force to the soft stamp (2, 2'), wherein the at least one movable soft stamp holder element (4, 4', 4") is designed such that the force can be applied to the soft stamp (2, 2') in a defined direction of action relative to the plane, so that the soft stamp can be transferred into an alignment state. 2) Soft stamp holder according to claim 1, wherein the force is a compressive force. 3) Soft stamp holder according to at least one of the preceding claims, wherein the compressive force can be applied laterally to the outer edge of the soft stamp (2, 2'). 4) Soft stamp holder according to at least one of the preceding claims, wherein the compressive force can be applied in the direction of a center point of the soft stamp holder. 5) Soft stamp holder according to at least one of the preceding claims, wherein the soft stamp holder has at least two movable soft stamp holder elements (4, 4', 4"), wherein the at least two movable soft stamp holder elements (4, 4', 4") are arranged on opposite sides of the soft stamp holder, so that the respective forces can be applied in the direction of the center point. 6) Soft stamp holder according to at least one of the preceding claims, wherein the soft stamp holder is configured for transfer into the alignment state such that the magnitude of the force acting on the soft stamp (2, 2') is increased in a controlled manner until deformation of the soft stamp (2, 2') occurs. 7) Soft stamp holder according to at least one of the preceding claims, wherein the soft stamp holder is designed such that the magnitude of the force acting on the soft stamp (2, 2') is adjustable such that in the aligned state the soft stamp (2, 2') has an increased flexural rigidity. 8) Soft stamp holder according to at least one of the preceding claims, wherein the soft stamp holder is designed such that the magnitude of the force acting on the soft stamp (2, 2') is adjustable such that in the aligned state the soft stamp (2, 2') is deformed, in particular compressed, by less than 1 mm, preferably less than 100 micrometers, particularly preferably less than 10 micrometers, in the optimal case less than 1 micrometer. 9) Soft stamp holder according to at least one of the preceding claims, wherein the force is between 0.1 N and 100 kN, preferably between 1 N and 500 N, particularly preferably between 10 N and 300 N, in the optimal case between 100 N and 250 N. 0) Device for embossing a substrate with a soft stamp (2,'), at least comprising: - a soft stamp holder according to at least one of the preceding claims, for receiving the soft stamp (2, 2') in a flat surface, - a substrate holder for holding the substrate, - Alignment means for aligning the substrate and the soft stamp (2, 2') to one another, wherein the at least one movable soft stamp holder element (4, 4', 4") is designed such that when the force is applied, the soft stamp (2, 2') can be transferred into an alignment state, and wherein the alignment means are designed such that the alignment can be carried out in the alignment state. 1) Method for embossing a substrate with a soft stamp (2, 2') with the following steps, in particular in the following order: i) providing a soft stamp (2, 2'), wherein the soft stamp (2, 2') is held by a soft stamp holder in a flat surface, ii) applying a force to the soft stamp (2, 2') to transfer the soft stamp into an alignment state, iii) aligning the substrate to the soft stamp (2, 2') in the alignment state, iv) removing the force acting on the soft stamp (2, 2'), v) embossing the substrate with the soft stamp (2, 2')- 12) Method according to claim 1 1, wherein the method further comprises the following step after embossing: vii) applying a separating force to the soft punch (2, 2') in the opposite direction of action to the force for transferring to the alignment state. 13 ) Method according to at least one of the preceding claims, wherein the soft stamp (2, 2') has a plurality of force absorption points, so that the force acts uniformly on the soft stamp (2, 2'). 14) Method according to at least one of the preceding claims, wherein after the alignment in step iii), a soft stamp embossing surface and a substrate surface facing the soft stamp embossing surface are each held in an aligned position, so that the embossing takes place by an approach of the soft stamp (2, 2') and the substrate. 15) Method according to at least one of the preceding claims, wherein when applying the force for transferring to the alignment state in step ii), the force is continuously increased until deformation of the soft stamp (2, 2') occurs.

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