Imprinting device

Abstract

The imprint apparatus comprises a first carrier carrying a flexible stamp and a second carrier movable relative to the first carrier, the second carrier configured to carry a substrate having a resist layer. The second carrier includes a chuck and a set of chuck actuators for translating a portion of the chuck in a Z-axis direction. Each chuck actuator includes an actuator output and a lever arrangement between the actuator output and a chuck drive member. The lever arrangement allows for improved positioning accuracy and increased stiffness compared to direct control of position using the actuator output.

Description

Technical Field

[0001] The present invention relates to an apparatus for imprinting an imprint pattern of a flexible stamp onto a resist layer.

Background Art

[0002] Imprint lithography of the type disclosed in European Patent Application Publication No. 3126909 (A) has attracted interest as a possible alternative to more conventional mask-based optical lithography techniques because there is a prospect that imprint lithography can provide small (smaller) feature sizes to patterns transferred to substrates such as substrates of semiconductor devices over a wide range. In imprint lithography techniques such as substrate conformal imprint lithography ("SCIL"), a flexible stamp containing a relief feature pattern on its surface is typically brought into contact with a substrate carrying a resist material. The resist material is imprinted by the feature pattern. Subsequently, the resist material is developed, for example cured, and then the feature pattern is released from the resist material, leaving a patterned resist layer on the substrate.

[0003] In this process, a curable but fluid resist layer is applied to a substrate (e.g., a wafer) supported by a chuck. The flexible stamp is, for example, rubber, and the resist layer is cured (solidified) while being imprinted, leaving a cured relief complementary to the relief of the stamp relief layer in the resist layer after removing the stamp from the resist. The imprint process involves placing a thin flexible stamp formed from, for example, a PDMS rubber layer adhered to a thin flexible plate such as a metal plate or a glass plate having a relief surface of the PDMS layer on the side opposite to the glass plate side, in a stamp manipulator. This stamp manipulator is also known as a groove plate. Thereby, the glass plate becomes relative to the stamp manipulator, and the relief surface of the stamp faces the resist layer of the wafer in the chuck.

[0004] The stamp is generally, but not necessarily, held at a small distance along the Z-axis direction from the surface of the fluid resist layer by two parts parallel to each other in the X-Y plane, upside down, above the wafer. This small distance defines a so-called imprint gap between the relief surface of the stamp and the resist layer along the Z-axis direction.

[0005] The stamp is locally manipulated and can be released and attached locally and sequentially to the stamp manipulator, for example, by a stamp manipulator. The stamp manipulator often has openings in the form of grooves extending along the surface (X-Y plane) of the stamp manipulator, and thus is also known as a groove plate. These openings can be individually operated with a set pressure such as overpressure or negative pressure to hold (negative pressure) or release (overpressure) the stamp. Therefore, during the imprint process, by releasing the stamp at one X-Y location (e.g., the edge), a first contact is made between the relief surface and the resist at that location. The stamp is then gradually released from the stamp manipulator and attracted to the resist layer mainly by capillary force. Thereby, the contact increases from the first contact location along the X-axis direction and / or the Y-axis direction according to the release method.

[0006] To enable the stamp to be attached to the manipulator, the stamp needs to be positioned upside down under the manipulator. To do this, the stamp is placed under the stamp holder (upside down with the relief surface facing down). The stamp manipulator is moved downward over the placed stamp facing the back side of the glass plate of the stamp, and then the glass plate surface of the stamp is attached to the manipulator by the operation of the manipulator opening.

[0007] Next, the substrate is loaded onto the chuck and positioned as desired with respect to the relief layer surface.

[0008] To set the imprint gap at the start of the process, the distance (in the Z-axis direction) needs to be set to a desired value (e.g., within the range of 50 μm to 150 μm) and maintained within strict tolerances during the imprint process (e.g., there is a gap variation within the range of 5 μm to 10 μm). The imprint gap is the gap between the wafer and the stamp.

[0009] During the imprint step, the manipulator opening is switched from negative pressure to a slight overpressure, gradually releasing the stamp from the stamp manipulator, whereby the feature pattern is attracted to the resist layer by capillary force because the spacing between adjacent protrusions of such a pattern generally acts as a capillary. Thus, this speeds up the wetting of the stamp by the resist. During and after the development (e.g., solidification) of the resist layer while in contact with the stamp, the feature pattern of the flexible stamp is released from the resist layer by an inverse process, in which individual manipulator openings are switched to negative pressure, thereby gradually releasing the feature pattern from the developed resist layer. The release process is generally hindered by the interaction between the stamp material and the developed (solidified) resist, which slows down the release process. This is due to an increase in the surface area between the stamp and the cured resist, which increases the van der Waals force per unit area. Therefore, with respect to an imprint apparatus such as the apparatus disclosed in International Publication No. WO 2008 / 068701 (A2), it is possible to set the speed of the imprint step or the release step.

[0010] In the current SCIL imprint machine, wafers with a diameter of 100 to 200 mm are used. A single linear Z stage is used for the vertical movement of the chuck to load and unload the wafer and also to adjust the imprint gap. The adjustment of the tilt (RX and RY) between the chuck and the groove plate is performed manually, for example, using three micrometer adjustment screws.

[0011] The height of the stamp landing ring in the existing machine is constant. The height can only be adapted by replacing the stamp landing ring with one of a different height.

[0012] There is a desire to scale up the design to enable printing of larger wafers such as 300 mm wafers. As a result, an increase in the required process power (e.g., twice as high) and a larger span width (e.g., 300 mm diameter instead of 200 mm) are obtained. To maintain the required imprint gap variation such as 5 - 10 μm during the process load, it is not possible to simply scale up the existing design. In particular, the support for the wafer does not have sufficient rigidity.

[0013] The support for the wafer includes, for example, a support frame such as a support and chuck of a C - frame design. The support frame can bend due to the process load or distortion during heating. As a result of the bending or distortion, the variation of the imprint gap becomes larger. This significantly degrades the quality of the imprint process. Larger chucks also have a large thermal mass, resulting in longer heating and cooling times.

Summary of the Invention

Problems to be Solved by the Invention

[0014] Therefore, one problem is the need to control the imprint gap quite accurately in the case of larger - area wafer supports such as chucks and groove plates (e.g., 300 mm diameter), while still allowing for easy loading of the stamp and wafer. This loading requires, for example, a longer - distance operation of the chuck with respect to the groove plate. In the case of larger chucks, it has further been found that the existing design is difficult to manufacture with tolerances that allow sufficient rigidity to ensure imprint gap control over the entire chuck area.

[0015] Another problem is to enable accurate and stable control of the position of the wafer support (known as the chuck).

[0016] Another problem is to ensure a uniform process gap between the stamp and the substrate, such as at the location of the stamp landing ring around the outer region of the stamp.

[0017] The present invention aims to address one or more of these problems.

Means for Solving the Problems

[0018] According to the present invention, a first carrier carrying a flexible stamp having an imprint pattern, a second carrier movable relative to the first carrier, and an imprint apparatus comprising: the second carrier includes a chuck configured to carry a substrate having a resist layer, a set of chuck actuators for translating a part of the chuck in a direction perpendicular to the plane of the second carrier, each chuck actuator including a chuck drive member, an actuator output portion, and a lever configuration portion between the actuator output portion and the chuck drive member, and a set of chuck actuators, an imprint apparatus is provided.

[0019] This imprinting device is a substrate conformal imprint lithography device or includes a substrate conformal imprint lithography device. The flexible stamp has an imprint pattern, and the first carrier includes, for example, an array of actuators (such as a manipulator aperture or an aperture) that are used to draw the flexible stamp towards the first carrier and to push the flexible stamp away from the first carrier. The array of actuators is a pressure-operated manipulator aperture or aperture, or includes a pressure-operated manipulator aperture or aperture, but other types, such as electric actuators or electromagnetic actuators, can also be used in combination with, for example, a flexible stamp having a metal support layer.

[0020] The chuck actuator enables control of the rotation of the chuck around the X-axis and Y-axis (in the plane of the chuck / substrate) and control in the Z-axis direction. Thus, tilt and wedge compensation are enabled, which can be manual and / or automatic based on local position detection. Precise control of the imprint gap is enabled.

[0021] Each chuck actuator includes an actuator output part and a lever configuration part between the actuator output part and the chuck drive member. The lever configuration part enables an improvement in positioning accuracy and an increase in rigidity compared to direct control of the position using the actuator output part.

[0022] The lever configuration part includes, for example, a first pivot between a fixed lever part and a movable lever part, and the lever configuration part results in a reduction in displacement between the actuator output part and the chuck drive member.

[0023] This reduction in displacement enables an improvement in positioning accuracy in the chuck drive member.

[0024] The first pivot includes, for example, a flexure pivot between a fixed lever portion and a movable lever portion. The use of the flexure pivot provides a frictionless attachment for the lever.

[0025] The chuck drive member includes a second pivot where the chuck drive member connects to the movable lever portion. This second pivot allows the chuck drive member to be oriented appropriately so that the positioning of the chuck (to the position where tilt and wedge compensation are performed) is consistent.

[0026] The second pivot also includes a flexure pivot. The use of the flexure pivot also provides a frictionless attachment for the chuck drive member in this case.

[0027] The lever assembly is biased, for example, towards the first holder by an adjustable spring assembly. The spring assembly determines the required stamp release force, which can be adjusted.

[0028] The lever assembly preferably includes a force sensor that monitors the force transmitted through the lever assembly between the actuator output and the chuck drive member. This force sensor is arranged in series with the chuck actuator and can be used to provide a feedback signal for detecting a stuck stamp or for providing damage protection.

[0029] The lever assembly includes, for example, a split gap that terminates at a notch flexure, and the force sensor is attached at that split gap.

[0030] The apparatus further includes a main frame and a main frame actuator that translates the main frame in a direction perpendicular to the plane of the second carrier. The chuck actuator is for translating a part of the chuck relative to the main frame, and the main frame actuator has a larger stroke than the chuck actuator.

[0031] The Z-axis movement of the chuck (perpendicular to the plane of the chuck / substrate) is divided into two stages by separate long-stroke and short-stroke drivers. This provides very rigid support. The chuck actuator enables control of the rotation of the chuck around the X- and Y-axes (within the plane of the chuck / substrate) as well as control in the Z-axis direction. Thus, tilt and wedge compensation are enabled, which can be manual and / or automatic based on local position sensing. Precise control of the imprint gap is enabled.

[0032] The main frame actuator has a large stroke (e.g., 50 mm or more) to facilitate loading of the stamp and substrate, and the chuck actuator has a small stroke for fine adjustment, e.g., up to + / -1 μm for a stroke of 5 mm.

[0033] The second carrier further includes a sub-frame, which is connected to the main frame, the chuck is attached to the sub-frame, and the sub-frame is attached to the main frame by a spring arrangement that biases the sub-frame against the first carrier via a kinematic coupling during imprinting.

[0034] The chuck is then carried by a rigid sub-frame. This sub-frame can then be separated from the main frame and the main frame actuator. The spring arrangement provides the separation between the sub-frame and the main frame. The sub-frame behaves as a rigid body, and deformations of the main frame and / or the main actuator do not affect the imprint gap. In particular, separation of the force path and the position path is implemented.

[0035] The chuck includes a set of position sensors that measure the distance from the surface of the chuck to the first carrier. These enable manual and / or automatic control of the chuck actuator.

[0036] The device further comprises a stamp landing ring (or more comprehensively a stamp landing device) around the outside of the chuck, and the stamp landing ring is for facing a first carrier outside the area of the flexible stamp. The stamp landing ring provides support for the substrate of the flexible stamp. The flexible stamp includes, for example, a glass substrate and a rubber stamp area on the central area of the glass substrate. Thus, the stamp has an edge area with a lower height (thickness) than the central area. The stamp landing ring enables the same process gap to exist over the area of the flexible stamp even if it has two regions of different heights.

[0037] The second carrier includes a set of position sensors that measure the distance from the stamp landing ring to the first carrier. These position sensors enable the position of the stamp landing ring to be controlled, for example, taking into account various stamp thicknesses and thus various height profiles of the flexible stamp.

[0038] The device further comprises a set of landing ring actuators each having a third stroke smaller than the first stroke, which translates a part of the stamp landing ring in a direction perpendicular to the plane of the second carrier relative to the main frame. Thus, the actuator for moving the stamp landing ring can also be incorporated into the second carrier.

[0039] The chuck includes a hollow cylindrical body having an upper surface and a lower surface. A lattice configuration is provided between the upper surface and the lower surface. This enables the reduced thermal mass of the chuck while maintaining the required rigidity to maintain a uniform imprint gap.

[0040] The upper and lower surfaces each include an internal waterway configuration that provides a flow path between a set of water inlets and a water outlet. The internal waterway configuration means that heating and cooling are performed not throughout the entire structure but at the upper and lower surfaces of the chuck, demonstrating effective thermal control, symmetric expansion, and contraction. Thus, heating and cooling at the upper and lower surfaces prevent buckling.

[0041] Embodiments of the present invention will be described in more detail by way of non-limiting examples with reference to the accompanying schematic drawings.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0043] The figures are not drawn to scale. The same reference numerals are used throughout the figures to indicate the same or similar parts.

[0044] The present disclosure provides an imprint apparatus including a first carrier carrying a flexible stamp and a second carrier movable relative to the first carrier. The second carrier includes a chuck and is configured to carry a substrate having a resist layer, and includes a set of chuck actuators that translate a part of the chuck in the Z-axis direction. Each chuck actuator includes an actuator output portion and a lever configuration portion between the actuator output portion and a chuck drive member. The lever configuration portion enables an improvement in positioning accuracy and an increase in rigidity as compared to direct control of the position using the actuator output portion. The Z-axis movement enables at least the approach and separation movement of the chuck relative to the flexible stamp carrier.

[0045] Before describing the present invention, with reference to FIGS. 1 to 4, the devices and methods disclosed in European Patent Application Publication No. 3126909 (A) and International Publication No. 2020 / 0099265 will be first described, and then modifications of this device for embodying the present invention will be described.

[0046] FIG. 1 shows an imprint device 100. The imprint device 100 is a SCIL imprint device or any other suitable imprint device that can be used to transfer an imprint pattern from a (flexible) stamp to a substrate.

[0047] The imprint device 100 typically comprises a first holder (e.g., a groove plate) as part of a first carrier 102 that holds a flexible stamp 104 including an imprint pattern 106 defined by recesses between protrusions. The first carrier 102 includes a frame (not shown) to which the holder is attached. The flexible stamp 104 and the imprint pattern 106 are realized in any suitable material, e.g., a suitable (synthetic) rubber material such as a polysiloxane-based material, e.g., polydimethylsiloxane (PDMS). A rubber layer is applied to a flexible stamp plate (not shown separately, made of, e.g., glass, plastic or metal). The feature size of the imprint pattern is of any suitable size, preferably a pattern on the micrometer scale or nanometer scale, i.e., a pattern having a feature size from about 10 nm to more than 1 mm, and the aspect ratio of the feature (vertical dimension divided by the horizontal dimension) can be 8 or more. However, other feature sizes can also be considered, and it should be understood that the present invention can be equally applied to transfer patterns having a smaller aspect ratio. For example, at least some embodiments of the present invention are suitable for transferring imprint patterns having an aspect ratio in the range of 0.001 to 10.

[0048] For this reason, the first carrier 102 typically comprises a plurality of stamp engagement elements 112 arranged in an array or grid (see, e.g., FIG. 2). Such stamp engagement elements 112 are typically configured to draw a part of the flexible stamp 106 towards the first carrier 102 in a first configuration and to push a part of the flexible stamp away from the first carrier 102 in a second configuration. Such elements may be referred to as stamp actuators. In the following detailed description, the stamp engagement element 112 is embodied by an aperture (opening) that can be switched between negative pressure (vacuum) and overpressure to provide the first configuration and the second configuration, respectively. For example, other actuators such as electromagnetic actuators may be used.

[0049] The aperture 112 can have any suitable shape. For example, the aperture 112 may be in the shape of a groove, the groove extending substantially over the entire length of the first carrier 102, or, as shown in FIG. 2, the aperture 112 may be circular, with the apertures 112 forming a two-dimensional grid. Other suitable shapes will be apparent to those skilled in the art. A groove-shaped aperture 112 is suitable, for example, when the imprint and release directions of the flexible stamp are the same or opposite to each other. For example, a two-dimensional grid of circular apertures 112, such as shown in FIG. 2, is particularly suitable when the imprint and release directions of the flexible stamp 104 are different from each other, as will be explained in more detail later.

[0050] Each aperture 112 includes a valve 114 that can switch the aperture 112 between an overpressure source provided via a first channel 140 (referred to as the "overpressure channel") and a negative pressure source, such as a vacuum pump at low pressure or an air reservoir, provided via a second channel 150 (hereinafter referred to as the "negative pressure channel"). The connection between each valve 114 and the negative pressure channel 150 is shown by a solid line, and the connection between each valve 114 and the overpressure channel 140 is shown by a dashed line. The negative pressure can be supplied at about 500 mBar to 900 mBar lower than atmospheric pressure, more preferably about 0.7 to 0.8 Bar lower than atmospheric pressure, i.e., at an absolute value of about 200 to 300 mBar.

[0051] Each valve 114 is typically controlled by a processing element (e.g., a processor) 160 that can take any suitable shape or form. The processing element 160 typically executes computer program code that instructs the processing element 160 on how to control the valve 114 and the first carrier 102 during the imprint process, as will be described in more detail later.

[0052] By switching the aperture 112 to negative pressure, the flexible stamp 104 is attached to the first carrier 102. Additional attachment means may be provided, for example, around the edge portion of the flexible stamp 104. Such attachment means includes, for example, a clamp that fixes the edge of the flexible stamp 104 to the first carrier 102, but it should be understood that in at least some examples, no additional attachment means are used.

[0053] The imprint apparatus 100 further includes a second holder 170 (also referred to as a second carrier) that holds the substrate 180 to be imprinted.

[0054] The second carrier 170 includes, for example, an aluminum or stainless steel chuck. The chuck is actuated for rough alignment using a micrometer spindle. The chuck is surrounded by a plate that functions as a stamper landing device or stamper landing ring that functions as described below in this specification. The device can be made from aluminum, stainless steel, or other individual materials.

[0055] To control the heat-based curing of the resist layer, a water channel inside the chuck is used for heating and cooling the chuck.

[0056] Any suitable substrate 180, such as any suitable semiconductor substrate such as a silicon substrate, a silicon-on-insulator substrate, a silicon germanium substrate, etc., can be used. For this purpose, the substrate 180 can carry a resist layer 182 that can be made of any suitable material. For example, the resist layer 182 can include a curable material that can be solidified (cured) to fix the imprint pattern 106 to the resist layer 182. In one example, the resist layer 182 includes a sol-gel material. Suitable examples of such materials are disclosed in International Publication No. WO 2009 / 141774 (A1), but it should be understood that any suitable resist material may be used. Further examples of suitable resist materials can be found, for example, in U.S. Patent Application Publication No. 2004 / 0261981 (A1), International Publication No. WO 2005 / 101466 (A2), U.S. Patent Application Publication No. 2005 / 0230882, U.S. Patent Application Publication No. 2004 / 0264019, and the non-patent literature Advanced Materials (1998, Vol. 10(8), p. 571).

[0057] The first carrier 102 is controlled by the processing element 160. For this reason, the imprint apparatus 100 further comprises means for positioning and repositioning the first carrier 102 relative to the second carrier 170 in three dimensions represented by three Cartesian coordinates X, Y, Z under the control of the processing element 160. Further, means are provided for adjusting the relative position in both the translational and rotational directions, in the lateral direction (direction parallel to the second carrier 170) and in the longitudinal direction (direction perpendicular to the second carrier 170). In this example, the apparatus includes automatic displacement means under the control of the processing element 160. The automatic displacement means includes, for example, a mechanical or electrical unit that provides a mechanical or electrical feedback mechanism for accurately controlling the relative XYZ position and the orientation of the first carrier 102 with respect to the second carrier 170. Such displacement means are known per se and will not be described in further detail here for the sake of brevity.

[0058] The second carrier 170 can optionally also be controlled by the processing element 160 in a manner similar to the above-described control means for the first carrier 102 in order to increase the degrees of freedom of the imprint apparatus 100. However, it is equally possible to provide an imprint apparatus 100 having a stationary or fixed second carrier 170.

[0059] The first carrier 102 is separated from the second carrier 170 by a gap 190, the size of which is controlled by the processing element 160, for example, by engaging means for positioning and repositioning the first carrier 102 relative to the second carrier 170. In a particular example, the processing element 160 is programmed to change the gap size between the imprint step and the release step. Specifically, since increasing the gap size can assist in the release of the imprint pattern 106 from the developed resist layer 182, the processing element 160 can be programmed to increase the gap size at the completion of the imprint step (and after developing the resist layer 182).

[0060] The overpressure channel 140 includes a pressure controller 192 under the control of the processing element 160. This facilitates changing the overpressure during the imprint step or the release step.

[0061] The imprint device 100 has a user interface such as a user terminal including at least one command input device such as a keyboard, a mouse, a trackball, etc. that enables a user to configure the imprint device 100 according to a desired imprint process. It should be understood that any suitable user interface may be used.

[0062] As described above, the processing element 160 is arranged to control the first carrier 102, the valve 114 and / or the pressure regulator 192. For this reason, the imprint device 100 further has a computer-readable data storage medium (not shown) such as a memory device, for example, a flash memory, a RAM or a ROM, a solid state disk, a magnetic disk, etc. The data storage medium includes computer program code for execution by the processing element 160, and this computer program code causes the processing element 160 to perform various steps of the imprint method. The data storage medium may be arranged at any suitable position of the imprint device 100. The data storage medium may be integral with the processing element 160 or an individual component accessible by the processing element 160 in any suitable way, for example, via a data communication bus or a point-to-point connection between the processing element 160 and the data storage medium.

[0063] A typical imprint process using the imprint apparatus 100 is as follows. A flexible stamp 104 including an imprint pattern 106 is attached to a first carrier 102 by switching a valve 114 so that, for example, an aperture 112 is connected to a negative pressure channel 150 connected to a negative pressure source such as a vacuum pump. Subsequently, the first carrier 102 is positioned above a second carrier 170 carrying a substrate 180 coated with a resist layer 182 such that the imprint pattern 106 faces the resist layer 182. The first carrier 102 is typically positioned relative to the second carrier 170 such that a gap 190 defined by the user of the imprint apparatus 100 to ensure good conformal contact between the flexible stamp 104 and the substrate 180 during imprinting exists between the first carrier 102 and the second carrier 170. The gap 190 is selected within any suitable range. For example, in a typical SCIL where the imprint pattern 106 is a nanoscale pattern, the gap 190 is selected in the range of 10 to 500 μm, preferably in the range of 20 to 200 μm, more preferably in the range of 10 to 100 μm.

[0064] Once the first carrier 102 is positioned relative to the second carrier 170, the imprint process proceeds to an imprint step where a contact region is formed between the flexible stamp 104 and the substrate 180, and the contact region is gradually expanded until the entire imprint pattern 106 intended to contact the substrate 180 is in contact with this substrate.

[0065] Figure 3 shows the imprint process. In Figure 3, the imprint pattern 106 is omitted merely for clarity.

[0066] As can be seen by looking at the upper part of FIG. 3, an initial contact region 194 is formed between the flexible stamp 104 and the substrate 180 by individually switching the selected aperture 112 from a negative pressure to a positive pressure in the direction of the horizontal arrow 200 above the positive pressure channel 140. In FIG. 3, only the selected connections between the valve 114 and the respective channels 140 and 150 are shown for clarity. Thereby, in order to establish a contact region 194 between the flexible stamp 104 and the second carrier 170 including the substrate 180 carrying the resist layer 182, a part of the flexible stamp 104 bulges away from the first carrier 102 and towards the second carrier 170. A space 196 is formed between the first carrier 102 and the flexible stamp 104.

[0067] The contact region 194 is typically expanded by moving the contact front surface of the contact region 194 in the direction of the aforementioned arrow by periodically switching the next aperture 112 from a negative pressure to a positive pressure by controlling the valve 114, as shown in the lower part of FIG. 3. This process is repeated until the contact region 194 is established over the desired area of the substrate 180, i.e., until the desired portion of the imprint pattern 106 is in contact with the resist layer 182. The rate at which the contact region 194 expands is typically determined by the rate at which the next aperture 112 is switched to a positive pressure and the gap 190. The associated bridge width W, where the stamp is not in contact with either the first carrier 102 or the substrate 180, is selected, for example, between 10 mm and 50 mm.

[0068] Once the desired contact region 194 between the imprint pattern 106 and the substrate 180 is established, subsequently, the resist layer 182 is developed, for example, cured by exposure to an external stimulus such as any suitable method, for example, UV or visible light, heat, etc. Thereby, the resist layer 182 is solidified and the imprint pattern 106 is fixed to the developed resist layer 182.

[0069] At this stage, the gap 190 is adjusted, i.e., increased, in order to shorten the duration of the release step in which the imprint pattern 106 is released from the developed resist layer 182. Not all gap settings facilitate the automatic release of the stamp. Depending on the types of the imprint pattern 106 and the resist layer 182, the stamp 104 can adhere to the developed resist layer 182 imprinted by a relatively high contact area 194 and thus by force. The release force that can be generated is higher when the gap 190 is larger. For example, the stamp 104 may not be able to release from the developed resist layer 182 when the gap 190 is set to 50 microns, but may be able to release when this gap is 100 microns.

[0070] FIG. 4 is used to illustrate how the stamp is released. During the release step, each aperture 112 is switched from the overpressure channel 140 to the negative pressure channel (vacuum) 150 by the processing element 160 controlling the respective valve 114, whereby the flexible stamp 104 rises, i.e., the flexible stamp 104 is peeled from the developed resist layer 182, the vacuum is sealed, and the bridge length W is shortened by one aperture pitch. This increases the force applied to the contact surface 194, and as shown in the lower part of FIG. 4, more apertures 112 are switched to negative pressure to displace the contact front of the contact area 194 in the direction of the horizontal arrow 210, so that the bridge becomes even shorter. The bridge shortens until the force equals the release force of the imprint pattern 106 of the flexible stamp 104 from the developed resist layer 182 on the substrate 180 carried by the second carrier 170. This then relaxes by the release of the stamp. When the gap 190 is larger, the stamp release is facilitated by the higher force perpendicular to the substrate wafer. Also, the longer bridge length resulting from this larger gap 190 allows more force to be applied before the vacuum seal is lost between the portion of the stamp 104 and the apertures 112 of the first carrier 102 that holds the flexible stamp 104 in place, e.g., the apertures 112 that contact the outer edge of the flexible stamp 104.

[0071] During the release of the stamp from the cured resist layer, it is noted that the flexible stamp 104 is in equilibrium with the force required to release the stamp. The next aperture 112 can be switched to negative pressure, such as a vacuum, only after a part (average) of the flexible stamp 104 having a size corresponding to the distance from aperture to aperture is released. Thus, the speed of release of the flexible stamp 104 from the substrate 180 is also determined by the gap setting. For example, if the flexible stamp 104 can be released using gaps of 50 and 100 microns, the release speed for a 100 micron gap is higher than that for a 50 micron gap, and thus a higher release speed, i.e., the speed at which the individual apertures 112 are switched to negative pressure along the direction indicated by the horizontal line, can be applied by the processing element 160, i.e., by periodically switching the corresponding valve 114 to the negative pressure channel 150. For the highest throughput of the overall imprint process, the setting of the gap 190 for the imprint step is different from the gap 190 required for optimal stamp release during the release step shown in FIG. 4.

[0072] Further details of the printing processes known from European Patent Application Publication No. 3126909 (A) and International Publication No. 2020 / 0099265 are disclosed.

[0073] As described above, there is a desire to scale up the design to enable printing of larger wafers, such as 300 mm wafers. As a result, an increase in the required process force (e.g., twice as high) and a larger span width (e.g., 300 mm diameter instead of 200 mm) are obtained. It is not possible to simply scale up the existing design to maintain the required imprint gap variations, such as 5 - 10 μm during the process load. In particular, the second carrier 170 (including the chuck and the support chuck frame) does not have sufficient rigidity.

[0074] In particular, the conventional C-frame design implemented by connecting the chuck frame and the groove plate bends due to the process load. As a result of the bending, greater variations in the imprint gap occur. This significantly degrades the quality of the imprint process.

[0075] The chuck frame may also distort during heating. Some distortion is allowed to a certain extent, but after cooling to room temperature, distortion is not allowed.

[0076] The chuck frame also has a large thermal mass, resulting in longer heating and cooling times. The thermal temperature gradient across the chuck can also become overly high when the size is scaled up.

[0077] There is a need to control the imprint gap in the case of larger area chucks and groove plates (e.g., 300 mm diameter) while still allowing for easy loading of the stamp and wafer. This requires, for example, operating the chuck at a longer distance with respect to the groove plate (i.e., as part of the first carrier 102). In the case of larger chucks, existing designs are difficult to manufacture with tolerances that allow sufficient rigidity to ensure gap control across the entire chuck area.

[0078] A first aspect of the present invention relates to a chuck manipulator.

[0079] FIG. 5 shows the design of a chuck manipulator.

[0080] This figure shows a chuck 500 surrounded by a stamp landing ring 502. The chuck 500 includes a chuck frame 504. The position of the chuck frame is adjustable by a micrometer adjustment screw 506.

[0081] The Z-axis position control of the chuck is controlled by a single Z-stage actuator 510.

[0082] This first aspect of the invention provides a two-piece frame chuck manipulator.

[0083] FIG. 6 shows an overall system including a sub-frame 600 to which a chuck 500 and a stamp landing ring 502 are attached. The chuck 500 is held by the sub-frame 600 and is further manipulated with respect to this sub-frame 600 using a set of three short-stroke manipulators 620 discussed further below. The three short-stroke manipulators 620 (i.e., chuck actuators) are angularly spaced around the chuck 500.

[0084] The sub-frame 600 is considered to be the main structural part of the second carrier and is thus considered to be equivalent to the support 170 in FIG. 1.

[0085] The chuck is designed to hold a 200 mm wafer or a 300 mm wafer in this example. The chuck has, for example, an outflow channel around the outer circumference of 200 mm diameter and another outflow channel around the outer circumference of 300 mm diameter.

[0086] The sub-frame 600 can be a bolted assembly, but can also be a welded or 3D printed structure. The sub-frame 600 including the chuck is treated as a sub-assembly attached to the main frame 610. The main frame 610 is operated with a long stroke driver 640 (i.e., the main actuator) with respect to a fixed world, i.e., the reference frame 630. The operation using the main actuator 640 enables long-distance chuck operations (e.g., 50 mm or more, e.g., between 50 mm and 250 mm) for loading the stamp and / or wafer or servicing parts of the chuck. Further, the main actuator 640 firmly fixes (i.e., presses) the sub-frame 600 against the groove plate (i.e., as part of the first carrier 102), in particular against the groove plate holder 612 that holds the groove plate and the frame 103, so that the chuck is short-stroked with respect to the groove plate 102 to control the imprint gap. The short stroke can be about 5 mm or less, such as 50 μm or less.

[0087] At the same time, the sub-assembly of the sub-frame 600 and the chuck 500 is biased towards the groove plate by the buffer spring component 662 discussed below. This allows for design defects in the parts that cause misalignment of the relative orientation of the sub-frame 600 with respect to the groove plate. Errors resulting from movement can also be compensated for.

[0088] FIG. 6 shows that the sub-frame 600 has a set of contact buffers 670, and the sub-frame 600 is pressed against the groove plate holder 612 through these contact buffers. These are discussed further below. More specifically below, three chuck actuators 620 are also discussed. The chuck actuators are arranged at the corners of a triangle (preferably an equilateral triangle), the triangular frame defines the sub-frame 600, and the sub-frame 600 supports the chuck 500. Each of the chuck actuators includes a lever component 621 discussed below.

[0089] Inside the sub-frame 600, three independent actuators and related lever components support the chuck. In this way, the imprint gap can be automatically adjusted not only for rotation about the X and Y axes but also in the Z axis direction (e.g., up to + / -1 μm). As shown below, the support of the chuck is formed using a flexure mechanism without play and friction.

[0090] Inside the sub-frame, there are also three independent actuators (i.e., landing ring actuators) and levers that support the stamp landing ring. They are for translating a part of the stamp landing ring in the Z axis direction.

[0091] Therefore, the position of the stamp landing ring relative to the chuck is also automatically adjustable not only for rotation about the X and Y axes but also in the Z axis direction (up to + / -1 μm). This enables adjustment for the thickness of the stamp and / or any taper in the stamp thickness, since the stamp landing ring is contacted by the glass carrier plate of the stamp.

[0092] The settings described above in the figure take into account strict control of the imprint gap and the orientation of the associated wedge of the stamp face relative to the chuck face, while still allowing long-stroke operation of the chuck.

[0093] Note that the (XY) plane alignment of the stamp face relative to the chuck face, i.e., the translation and / or Z-axis rotation of the stamp face relative to the chuck face in the X and / or Y axis directions, is performed by operation of the groove plate 102 relative to its holder 612. The groove plate 102 has a groove plate frame 103 driven by three linear actuators (shown further below), and the groove plate frame is supported by the groove plate holder 612 by an air bearing 884. This will be further explained below. The groove plate alignment is separate from the gap (Z-axis direction) alignment.

[0094] The use of a separate long-stroke (main) actuator and a short-stroke (chuck) actuator provides very firm support for the chuck in the Z-axis direction.

[0095] Three distance sensors are used to measure (and calibrate) the distance between the upper part of the chuck and the glass plate of the stamp, i.e., the groove plate. The three distance (and thus position) sensors are also used to measure (and calibrate) the distance between the upper part of the stamp landing ring and the glass plate of the stamp. These sensors enable automatic control of the chuck actuator and the landing ring actuator without the need for manual adjustment.

[0096] FIG. 7 shows a plan view of the sub-frame 600.

[0097] The sub-frame 600 functions as a rigid body and internally responds to process forces. The sub-frame 600 is a structure that extends around the chuck, such as the ring 602, but may be polygonal.

[0098] The sub-frame 600 is rigid and holds the chuck 500 and the stamp landing ring 502. The landing ring actuator 620a is between the stamp landing ring 502 and the sub-frame 600, and the chuck actuator 620b is between the chuck and the sub-frame 600. The actuators can independently translate three edges of the chuck / stamp landing ring in the Z-axis direction (e.g., perpendicular to the upper surface of the chuck) with respect to the sub-frame 600. These take into account the maximum gap control for the entire chuck area and the stamp landing ring 502.

[0099] Fixing is also used to ensure the thermal center of the chuck, and the sub-frame 600 remains in place during the same type of expansion. The fixing defines the connection between the chuck and the sub-frame 600. Those fixings have enough play to allow for the difference in thermal expansion between the two parts, but when the kinematic coupling described above is formed, this play does not allow for any relative movement.

[0100] Returning to FIG. 6, the sub-frame 600 is attached (in this case, placed) to the main frame 610. The main frame 610 is slidably supported on a reference frame 630 (the external world). The main actuator 640 is between the main frame 610 and the reference frame 630 to operate the main frame 630 (as well as the sub-frame 600 and the chuck) with respect to the reference frame 630.

[0101] The groove plate holder 612 and the groove plate 102 are also attached to the reference frame 630.

[0102] The attachment of the sub-frame 600 to the main frame 610 is spring-buffered at three locations. Two spring components 662 are shown in FIG. 6. Although not shown, the spring component 662 may include an outer large-diameter buffer spring and an inner small-diameter buffer spring (not visible). The buffer springs apply a pressing force while playing a role in compensating for alignment errors. Those buffer springs bring about a firm connection between the sub-frame 600 and the groove plate 102.

[0103] As described above, the sub-frame 600 has three contact buffer portions 670 (the upper half of which has a spherical shape with a circular bottom surface) on its upper surface (opposite to the side placed on the main frame 610). The contact buffer portions are spherical with a circular bottom surface. These contact buffer portions are for pressing the sub-frame 600 against the groove plate holder (at the position of the kinematic coupling) when the imprinting machine is in the imprinting stage.

[0104] When loading a wafer or a stamp, the buffer 670 is disengaged when the main frame 610 is operated using the main actuator 640 to lower the sub-frame 600 from the groove plate. The pressing is very firm so that the groove plate holder and the sub-frame 600 effectively become one rigid part. The spring-biased connector 662 between the sub-frame 600 and the main frame 610 ensures that any alignment error (due to any cause) between the groove plate and the sub-frame 600 is compensated for by these connections. The spring component 662 presses the sub-frame 600 against the groove plate holder.

[0105] In this way, the gap control is affected only by the overall groove plate and the sub-frame 600, which functions as a single component, and is thus independent of the instabilities of the main frame 610 and the reference frame 630.

[0106] The kinematic coupling between the sub-frame 600 and the groove plate holder may be based on balls and grooves rather than protrusions with flat surfaces.

[0107] The sub-frame 600 is attached to the main frame 610 by three pins and three slots in the region 666.

[0108] The slots are oriented at angles of 0°, 120°, and 240°. The pins and slots have a play of several micrometers. However, this play does not cause any movement during the imprint process due to the high friction in the kinematic coupling provided by the buffer 670. The force that the alignment motor can generate is much lower than the friction in the kinematic coupling.

[0109] As described above, each of the spring components 662 has an inner spring 664 with a smaller diameter within each of the springs 662 with a larger diameter for automatic mechanical overload protection. The two-spring design is optional. During normal processing, the main actuator (long-stroke driver) operates at high speed. The impact of a collision may cause serious damage to the groove plate. A collision may occur when a substance not belonging to the chuck is in the chuck or when, for example, a wafer of excessive thickness is being used.

[0110] The spring component means that the sub-frame 600 is pressed to the kinematic coupling by two springs in series at each corner of the sub-frame 600. The two springs have various force characteristics. First, only the weaker spring is used to raise the sub-frame 600. After contacting the kinematic mount, the stronger spring presses the sub-frame 600 against the kinematic mount. This two-step approach provides the time required to decelerate the spindle drive motor of the main actuator.

[0111] As described above, the chuck actuator 620 provides a Z-axis position (i.e., perpendicular to the plane of the substrate and the stamp). The Z-axis positioning at three locations provides three degrees of freedom ("DOF") in that it can control the Z-axis translation as well as the rotation about the X-axis and Y-axis.

[0112] The groove plate has in-plane positioning control, provides X-axis and Y-axis translation, and can provide rotation about the Z-axis. Thus, 6DOF position adjustment is possible with a simple structure that maintains the desired rigidity of the carrier. The position control is divided between the groove plate and the chuck.

[0113] In the above-described design, the deflection of the reference frame 630 and / or the main (long stroke) actuator has no effect on the imprint gap. In particular, the sub-frame 600 is separated from the main actuator by the contact buffer 670. In this way, the separation of the force path and the position path is established.

[0114] In the above example, a separate chuck actuator is utilized to move the chuck relative to the sub-frame 600 and the actuator to move the groove plate. Alternatively, the chuck can be supported by a hexapod inside the sub-frame 600. The hexapod serves as a substitute for the three chuck actuators 620 of the chuck. The hexapod can move in six axes. The so-called overlay alignment for X-axis and Y-axis translation and rotation about the Z-axis (for the adjustment of the stamp with respect to the wafer) is implemented in the design shown above by moving the groove plates 102 and 103 inside the groove plate holder 612 or the groove plate holder 888 in FIG. 14, which functions as an alignment station (see FIG. 14). In the case of the hexapod, this can also be done by moving the chuck in 6DOF. However, this may pose further difficulties in enabling a sufficiently accurate overlay alignment and sufficient Z-axis rigidity of the chuck support. The hexapod will also reduce rigidity and lower the accurate alignment performance, but the module can be simplified so as to reduce the manufacturing and development costs. In that case, a linear actuator for the groove, an air bearing, a short stroke manipulator or a flexible hose is not required.

[0115] As an alternative to the pins and slots 666 used to attach the sub-frame 600, flexures such as the bending of a folded sheet can also be used.

[0116] The illustrated configuration allows for automatic tilt adjustment of the chuck for rotation about the X and Y axes. In some designs, the position of the stamp landing ring relative to the chuck can also be automatically adjusted using position sensing. Wedge compensation is also possible (i.e., the parallelism error of the stamp).

[0117] A second aspect of the invention relates to the design of the chuck, which also allows for the above-described dimensional increase in this case.

[0118] FIG. 8 shows a chuck 500. The upper depiction shows a perspective view showing the top, and the lower depiction shows a partial cutaway perspective view for showing the internal structure. The chuck 500 has a flat upper surface for receiving a wafer. The chuck 500 is designed to receive a 200 mm diameter wafer or a 300 mm diameter wafer. Vacuum openings 800 are positioned at approximate locations around the outer periphery of the wafer. These vacuum openings are for clamping the wafer. Radially outside the vacuum openings 800, there is an annular outflow groove 801 for capturing resist excess that may occur during the imprint step. The outflow groove 801 prevents the chuck from being contaminated by the wet resist on the wafer. The resist will not stick to the chuck 500 if it does not contact the chuck 500.

[0119] The upper surface also has an opening 802, which allows the wafer to be raised and lowered relative to the chuck 500 by passing lift pins through it.

[0120] The chuck 500 is formed as a hollow structure. This allows it to have a large thickness to provide the required rigidity while having a low thermal mass. The chuck 500 is generally cylindrical. Attachment points 810 are formed on the outer periphery, and these engage with the chuck actuator 620. At each of these attachment points, there is also a sensor 812 for measuring the spacing relative to the groove plate.

[0121] A hollow lattice structure is defined between the top and bottom surfaces. These top and bottom surfaces include a channel configuration for temperature control. To provide symmetry and prevent buckling, the same temperature control is performed on both the top and bottom surfaces. For example, the structure and channel layout are the same.

[0122] The channel configuration covers, for example, the entire area of the chuck. The temperature control of the top surface is for heating and cooling the wafer and, by extension, the resist layer provided on the wafer.

[0123] A lattice structure 814 exists within the hollow region between the top and bottom surfaces to provide rigidity and hardness. Thus, there is a sandwich design with a lattice structure inside to provide the desired rigidity. The lattice structure is, for example, a cubic lattice (simple, centered body, or centered face) or a hexagonal lattice. The cell size and beam size are selected to provide the required rigidity.

[0124] All connections for the channels (e.g., a set of water inlet ports and a single water outlet port) and the vacuum connection are arranged on the bottom surface of the chuck.

[0125] The chuck 500 is designed to be manufactured, for example, by powder bed melting for metal 3D printing. The chuck is made of stainless steel. After 3D printing and powder removal, the finishing is done by a milling machine. Through the lapping process at the end point, the required flatness of 5 μm is achieved for the top surface.

[0126] Figure 9 shows the internal structure in more detail. The upper part of Figure 9 is a cross-section showing the top surface 820 and the bottom surface 830, each surrounding a channel configuration. The thickness of each surface is, for example, 5 mm, with a 1.5 mm skin above and below a 2 mm water layer.

[0127] The total thickness of the chuck is, for example, in the range of 40 mm to 100 mm thick.

[0128] Not only the outflow channel 801 but also two vacuum openings 800 are shown. Two alignment pin slots 802 are also shown.

[0129] The lower part of FIG. 9 is another cross-sectional view showing how heated water (e.g., at 60 - 70 degrees) or cooled water (e.g., at 20 degrees) is supplied to the channel configurations on the upper and lower surfaces. One water supply duct 840 is shown. There are, for example, six such supply ducts around the periphery of the chuck.

[0130] The supply duct 840 has its bottom surface open to the channel configuration within the lower surface 830 and also has a conduit 842 between the lower surface 830 and the upper surface 820, and the conduit 842 terminates in the channel configuration within the upper surface 820.

[0131] The upper surface 820 and the lower surface 830 enclose their respective channel configurations. The central grid region of the chuck is sealed from the water supply.

[0132] Rather than causing deformation of the peripheral components of the chuck that could result in a loss of flatness, the conduit 842 has a bellows structure so that the axial stress in the conduit can be compensated by the deformation of the conduit. However, the bellows of the conduit is an integral part of the chuck structure.

[0133] The chuck has, for example, a single water outlet duct at the center of the chuck to collect the water after it passes through the channel configuration.

[0134] FIG. 10 shows a cross-section of the entire chuck. FIG. 10 shows that the central water outlet duct 844 has the same bellows design as shown in FIG. 9.

[0135] Figure 11 shows a set of ridges 850 in the upper or lower surface that define the channel configuration. Thus, Figure 11 shows the open area of the upper channel configuration or the lower channel configuration. The upper depiction is a plan view, and the lower depiction is a perspective view showing the three-dimensional characteristics of the ridges and protrusions. Six fluid inlet ducts 840 are spaced apart around, two of which are shown in Figure 11, and a single fluid outlet duct 844 is shown in the center. The ridges 850 mean that water has to follow a meandering path with circumferential and radial path sections from the locations of the fluid inlet ducts to the fluid outlet duct. The ridges 850 form a set of discontinuous annular paths, and the gaps within one annular path are offset with respect to the gaps in adjacent paths so as to define the meandering path. In addition to the ridges that function as dams, there are struts 852 around the annular paths, and the struts 852 serve to support the skin and keep it flat and may additionally or alternatively increase the turbulence.

[0136] This design results in a uniform water temperature distribution covering the entire area of the chuck, which is caused by multiple water mixing locations.

[0137] All the connections for water supply and removal and the vacuum connections are arranged on the lower surface of the chuck (beneath it). This leaves space for the movable stamp landing ring around the chuck.

[0138] A thermal sensor may be additionally attached to the lower surface. Thus, sensors for measuring temperature may be present on both the upper and lower surfaces.

[0139] Figure 12 shows the underside of the lower surface, showing the surrounding water inlet connections 860, the central water outlet connection 862, the vacuum connections VAC1 and VAC2, and the cavity connections CAV1 - CAV6.

[0140] These cavity connections provide openings at various locations on the chuck surface and are connected to a pressure source that applies negative or positive pressure.

[0141] The cavity is used to enable printing on both sides of the wafer. After the first side is printed, the pattern should not be touched, and in particular, it should not be pressed onto a flat surface if it is flipped over.

[0142] To enable double-sided printing, an interface plate 870 as shown in FIG. 13 may be provided on the chuck. The interface plate is a metal or aluminum plate that can be removably positioned on top of the chuck. FIG. 13 shows an example of the interface plate in a perspective view (upper figure) and a cross-sectional view on the chuck 500 (lower figure).

[0143] The interface plate 870 has a grid of openings 872 such that when the wafer 180 to be printed is placed on the interface plate 870 (with the first already printed side facing down), the printed area of the wafer (scored to form separate products) is aligned with the openings. The grid lines 874 of the interface plate 870 are over (aligned with) the unpatterned area of the wafer.

[0144] The openings may pass straight through the plate 870 (e.g., 872a) or have a deviated shape (e.g., 872b) as can be seen in the cross-sectional view of FIG. 13. A sufficient depth is required to receive the printed substrate layer so that the surface is not contacted. The extension of the opening 872 to the side of the plate facing the chuck is arranged such that when the plate is attached to the chuck, the opening aligns with the pressure line 873 within the chuck.

[0145] By providing a pressure line 873 that leads to the opening 872 through the chuck 500, the pressure within the cavity (opening) can be controlled simultaneously with the printing process. In particular, by providing a positive pressure when there is a printing bulge on the stamp, instead of using a solid chuck surface, a negative pressure is used via the pressure line to support the wafer against the pressure of the printing bulge during the printing process. When the printing bulge advances in the direction of arrow 876, support pressures are applied in sequence to the first through fourth columns C1 - C4 of the opening 872. Thus, for example, the interface plate of FIG. 13 uses four cavity (opening) connections. However, more columns of independently operable cavities may exist. FIG. 12 actually shows six independently operated cavity connections CAV1 - CAV6 below the chuck. The cavity connections lead to an opening within the chuck via the pressure line 873, and the opening within the chuck is positioned within the opening 872. When no positive pressure is applied, a negative pressure can be applied to those openings (which are closed by the wafer on the upper side of the interface plate) or a negative pressure is applied. The negative pressure supply helps, through a clamping action, to attach the wafer to the plate and the plate to the chuck.

[0146] The interface plate 870 is, for example, a 1 mm thick stainless steel plate preferably having a set of notches formed by chemical etching. To attach the interface plate over the chuck, the interface plate has, for example, a set of three openings through which the receiving pins of the chuck 500 are slid. The interface plate also has vacuum grooves 878 in the regions between the openings 872. The vacuum grooves 878 between and around the cavities clamp the wafer to the cavity plate.

[0147] Note that instead, the interface plate may be an integral part of the chuck. In such a case, the plate is not removable from the chuck.

[0148] As described above, the opening 872 prevents contact between the already imprinted structure and the wafer support. The interface plate also enables the wafer to be supported or clamped at any desired position. The opening is connected to overpressure air and / or vacuum via a chuck. The openings and channels in the lower part of the interface plate connect the supply part of the chuck to the cavity.

[0149] The interface plate 870 has a low thermal mass and a high thermal conductivity, and thus does not slow down the printing process as much as possible. The plate is preferably made of aluminum, but other materials such as stainless steel can also be used. Stainless steel has a lower thermal conductivity (less preferred) than aluminum, but due to the thinness of the plate, such a low thermal conductivity can be used. Those skilled in the art will know how to balance the thermal properties of the material and the geometric design to arrive at a useful plate.

[0150] The required flatness and parallelism of the cavity plate are approximately + / - 5 μm. For a stainless steel plate, this required flatness and parallelism can be achieved by using an etching process that forms the cavity. In milling, stress is generated in the material that can cause accidental deformation.

[0151] The interface plate 870 provides a lot of flexibility for implementing further designs. The chuck 500 itself cannot be changed for imprinting various designs. However, for each stamp design, a separate interface plate 870 can be designed and manufactured.

[0152] Using a pin and slot connection (e.g., a combination of two or more, preferably three or more pins and slots) between the interface plate 870 and the chuck 500 can prevent movement due to thermal expansion and can also prevent or reduce distortion.

[0153] Here, several design options will be described.

[0154] A stainless - steel plate is preferred. Regarding the stainless - steel plate, the plate is preferably thinner than 2 mm. A thin plate has a lower thermal mass and a higher thermal conductivity compared to a thicker plate. The thin plate also has a low rigidity so that it can be easily bent. The plate itself aligns with the flat upper surface of the chuck under vacuum force. The thin plate also shows good heat transfer from the chuck to the cavity plate. The flatness requirement, which can be important for the imprint gap, is also met. The thin plate is also preferred for the range of the chuck's short - stroke manipulator, such as 2 mm.

[0155] However, the plate should not be too thin. If it is too thin, the vacuum channels cannot be made deep enough, resulting in excessive flow losses and an insufficient level of vacuum. In that case, the force to hold the wafer on the cavity plate is too small. The cavity and grooves can be made or are made by a chemical etching process.

[0156] Stainless steel has a much lower thermal conductivity than aluminum. Nevertheless, the stainless - steel plate will add only a time below approximately 2 seconds of heating time and 2 seconds of cooling time.

[0157] An aluminum plate is possible but not a very preferred option. Regarding the aluminum interface plate, aluminum has a better thermal conductivity and a lower thermal mass than stainless steel. Therefore, aluminum can be made thicker for better manufacturability. Stress - free cast aluminum can only be obtained from a thickness of 10 mm and above. Ordinary aluminum sheet materials already have too much internal stress due to the rolling process of the raw material.

[0158] In the case of a thicker plate, the vacuum channels can be made deep enough so that as a result, sufficient flow occurs and a vacuum strong enough to hold the wafer is generated. In this case, the cavities and grooves cannot be produced by a chemical etching process. Chemical etching is not possible using aluminum. Alternative milling causes stress in the material, which may cause accidental deformation. Annealing without tension may be used.

[0159] A thicker aluminum plate is stiffer than a thin stainless steel plate. However, a thicker aluminum plate does not align itself with the flat upper part of the chuck. This results in a gap between the chuck and the cavity plate, and thus there is a possibility of vacuum leakage, and as a result, the vacuum for holding the cavity plate to the chuck is lost. Further, such a gap reduces heat transfer between the plate and the chuck, and thus reduces the heating and cooling rates during use of the apparatus.

[0160] However, in the case of an aluminum plate, it is difficult to achieve the desired heat transfer from the chuck to the cavity plate and to meet the flatness requirements that are important for controlling the imprint gap. Due to the short stroke manipulator of the chuck, thicker plates are also not preferred. However, in a printing machine having only one Z stage, a thicker plate can be used.

[0161] As described above, the short stroke manipulator (i.e., the chuck actuator 620) is another aspect of the design of the present invention.

[0162] The same design of the short stroke manipulator can be used as a rigid support and drive configuration not only for the stamp landing ring but also for the chuck. The short stroke manipulator, when combined with the positioning of the groove plate as described above, is used to position the chuck and the stamp landing ring with six degrees of freedom (i.e., three translations and three rotations).

[0163] The chuck, the groove plate, and the stamp landing ring each need to be supported with 6 DOF and accurately aligned.

[0164] The groove plate can move with 3 DOF (translation along the X-axis, translation along the Y-axis, and rotation about the Z-axis), and the other three (translation along the Z-axis and rotation about the X-axis and Y-axis) are fixed.

[0165] The chuck and the stamp landing ring can move with 3 DOF (translation along the Z-axis and rotation about the X-axis and Y-axis), and the other three (translation along the X-axis and Y-axis and rotation about the Z-axis) are fixed. One short stroke manipulator supports 2 DOF (translation along the Z-axis and fixed translation along the X-axis).

[0166] The manipulator is used for fine adjustment of the chuck and the stamp landing ring in the Z-axis direction and for rotation about the X-axis and Y-axis. As will be further described below, the chuck actuator is also used for force measurement and shock absorption.

[0167] Therefore, the 6 DOF alignment and operation between the stamp and the wafer are realized by the following two separate alignment systems: (i) Overlay alignment from the stamp to the wafer, translation along the X-axis and Y-axis, and rotation about the Z-axis are implemented by the groove plate alignment (i.e., stamp alignment). (ii) Adjustment of the imprint gap, translation along the Z-axis, and rotation around the X- and Y-axes are performed by three short-stroke manipulators (providing chuck support).

[0168] For double-sided imprinting of the wafer (as described above), in addition to controlling the imprint gap, overlay alignment is essential. Overlay alignment specifications require very high positional accuracy. Friction- and hysteresis-free overlay alignment is critically important. A large alignment range, such as linear movement up to 5 mm or up to 15 mm, also needs to be covered in the horizontal plane. The allowable force of the piezo-stepper drive, such as a maximum value of 50 N, is also limited.

[0169] Controlling the imprint gap is achieved by the two-stage chuck support described above. For overlay alignment, two markers on the stamp and two markers on the wafer are used. The coordinates of these four markers are measured by a camera system on top of the groove plate. For this purpose, the groove plate is transparent. Both the wafer markers and the stamp markers need to be within the focus of the camera system (i.e., at the appropriate height).

[0170] The system compares the coordinates of the four markers and uses a transformation matrix to calculate the desired movement for the three short-stroke actuators. To achieve better accuracy, this control loop can be repeated several times.

[0171] As described above, one option for controlling all six DOFs is to operate only the chuck. For this purpose, a hexapod can be used as described above. However, a hexapod that meets the requirements is not commercially available. Splitting the alignment function in the manner outlined above makes it possible to meet the requirements.

[0172] One aspect of the present invention utilizes an alignment stage that includes a movable groove plate carrier 612. The groove plate carrier can be positioned by translation in the X-axis and Y-axis directions and rotation about the Z-axis (Rz) without any friction or backlash. A large alignment range in the horizontal plane of a desired linear movement of 5 mm (or even 15 mm) is possible.

[0173] FIG. 14 shows a drive configuration for the groove plate 102 (i.e., as part of the first carrier 102). This drive configuration functions as an alignment stage. The groove plate 102 has a groove plate frame 103 that is driven by three linear actuators 880 that are each connected to an associated pair of air bearings 884 via flexures 886, as also shown in FIG. 6. This is a preferred configuration, but the connection is not essential. The actuators can also be arranged at various positions or angles, for example, rotated 120 degrees relative to each other three times and rotated 60 degrees relative to the air bearings. These actuators may be referred to as "carrier actuators" to distinguish them from the chuck actuators and the stamp landing ring actuators. The groove plate is connected to the air valve terminal 882 via a flexible air tube to provide the printing pressure described above.

[0174] The groove plate frame can be positioned in the X-axis direction, Y-axis direction, and rotation about the Z-axis (Rz) without any friction or backlash.

[0175] Translation in the X-axis and Y-axis directions and rotation about the Z-axis are established by the three actuators 880. The required force for the linear actuators does not exceed, for example, 50 N. The actuators are attached to the fixed world (i.e., the base 888) and connected to the groove plate frame 103 via three flexures 886. The three flexures allow lateral movement orthogonal to the actuator movement. The lateral shift prevents the groove plate frame 103 from being overly constrained.

[0176] For the Z, Rx, and Ry fixation of the groove plate frame 103 inside the alignment stage, three pairs of air bearings 884 are used. The air bearings are attached to the fixed world 888. At each of the three corners, a pair of two air bearings 884 clamps the groove plate frame. (As can be seen in FIG. 6 and shown as a single unit in FIG. 14) One air bearing is on top of the groove plate frame and one air bearing is below. The groove plate frame 103 is clamped between the upper and lower air bearings, so that the air pressure is equalized (in the Z-axis direction). The three corners set a fixed horizontal frame, and movement within its plane is allowed by each pair of air bearings. The allowed movement is, for example, approximately 10 mm and is mainly required for Rz adjustment.

[0177] As can be seen in FIG. 6, one air bearing of each pair can be pre-loaded using a spring mechanism. This preload makes it possible to keep the air gap constant under all circumstances. The height of the air gap is a dominant factor for the rigidity of the groove plate support in the Z direction.

[0178] The displacement coordinates of the frame 103 are calculated by the transformation matrix.

[0179] During use, the markers on the wafer are positioned at the appropriate depth of focus by operating the chuck support, providing Z-axis positioning. After this, horizontal alignment can be carried out.

[0180] Note that an alternative to the six air bearings is a set of (e.g., three or four) bent leaf springs for Z-axis, Rx, and Ry fixation. A disadvantage compared to air bearings is that the bent leaf springs require additional force from a linear actuator to move the groove plate. The leaf springs (e.g., bent leaf springs) must be sufficiently tall, long, and thick to provide the required movement in the X-axis and Y-axis directions, as well as rotation (Rz) about the Z-axis, and the rigidity of the groove plate frame 103, resulting in greater force requirements for the (e.g., groove plate) actuator.

[0181] FIG. 15 shows in more detail the design of a short-stroke actuator 620 for use as a chuck actuator. The same actuator can be used for the stamp landing ring, and similarly, a sensor (described below) can be used for mechanical damage protection.

[0182] The chuck actuator includes a drive element 900, such as a piston, that drives the actuator tip 902 up and down. The position of the actuator tip 902 is fixed to the subframe at the connection 903, which is rigidly connected to the real world (i.e., the reference frame 630) during printing, as discussed below, so that as the actuator operates, the actuator output 904 in the form of a drive link moves up and down. A tension spring 906 pulls the short-stroke actuator upward. The upper part of the tension spring is connected to a pin 907, which is also connected to the subframe. The spring compression varies over the same distance as the stroke of the short-stroke manipulator.

[0183] The tension spring 906 is adjustable to ensure a pre-loaded manipulator without play. The adjustment is made by a threaded tube 908 that adjusts the position of one end of the spring (e.g., the side opposite the pin 907). The pre-tension of the tension spring 906 defines the allowable stamp release force. The higher the spring force, the higher the release force can be. The pre-tension of the spring can be made not too high due to the limited allowable load applied to the integrated force sensor 920 discussed below.

[0184] The actuator 900 includes a lever configuration having an actuator output portion 904 at one end and a chuck driver 910 at the other end. There is a pivot point 912 along the lever configuration, which is formed as a cross flexture pivot. The fixed component 914 of the lever configuration is connected to a reference frame (e.g., the sub-frame 600), and the main body 916 of the lever configuration is a movable component of the pivot point 912 that swings around the pivot location. The lever ratio is defined as the ratio of the distance (d2) between the pivot point 912 and the actuator output portion 904 to the distance (d1) between the pivot point 912 and the chuck driver 910. The lever ratio (d2:d1) is, for example, 4:1.

[0185] For example, a lever having a lever ratio of 4:1 ensures that the support provided at the chuck driver 910 is more than 4 times more accurate and 16 times more rigid in the Z-axis direction than if the actuator 900 did not have the lever configuration. Thus, by using the lever, the imprint gap is better controlled.

[0186] The force sensor 920 is for measuring the process load and is integrated inside the lever. This enables better monitoring of the imprint process. The force sensor 920 is part of a stiffness loop, and the force sensor is arranged in series with the actuator.

[0187] The main body 916 of the lever is divided by a groove 930 of, for example, 0.2 mm. The moment formed inside the lever by the force of the actuator is transmitted through the sensor 920 and the notch deflection part 932 without any hysteresis. The sensor in this example measures a force that is 0.443 times the load based on the ratio of d1:d3 (for example, 30 mm vs. 67.71 mm). d3 is the length of the rotating arm from the notch deflection part to the force sensor.

[0188] The connecting part 903, the pin 907, and the fixing part 914 are all connected to the sub-frame 600. However, in the use with the sub-frame pressed against the groove plate, the sub-frame is firmly connected to the reference frame (through the kinematic coupling). Therefore, the sub-frame 600 is pressed against the component 612 through the kinematic coupling 670.

[0189] The force sensor 920 includes a force sensor element 940 biased by a compression spring 942 against a seat on the split 930.

[0190] The seat provides overload protection for the sensor. The force sensor element 940 is pressed against the seat by the pre-compression spring 942. The seat moves only against the biasing of the spring when the force applied to the sensor exceeds, for example, 250 N.

[0191] As long as the force sensor element is pressed against the seat when there is no excessive force, the overload protection does not affect the rigid loop at all.

[0192] The actuator tip 902 of the drive element 900 is restricted by a stopper 950 fixed to the reference frame.

[0193] The stopper 950 includes a ring that is pressed against the tip by a spring 952. The ring can move against the biasing of the spring when the force applied to the sensor exceeds, for example, 250 N. The spring has no effect on the rigid loop unless the tip is compressed by the spring against the stopper. This prevents the actuator's spindle from being damaged by impact forces.

[0194] The force sensor and the actuator are thus protected from overload due to impact. For example, the load on the force sensor should be limited between -30 N and +300 N; otherwise, the sensor or the actuator may be damaged.

[0195] Negative forces on the sensor are prevented by the split groove design. The split groove inside the lever becomes wider in the case of negative forces, so the sensor rises from its contact point. Thus, the force is zero. However, positive forces can be higher than 300 N due to impact, so the force limiting configuration described above is used.

[0196] The force sensor can also detect a stuck stamp and can be used to prevent mechanical damage.

[0197] Stamp adhesion is a problem that is preferably detected. Stamp adhesion occurs when the stamp release sequence after the imprint process fails. This situation can occur when the stamp has been used too many times. The rubber relief part of the stamp is no longer removed from the wafer.

[0198] At the end of the imprint process, the support of the stamp (e.g., a glass plate or a metal plate) is held against the groove plate by vacuum, and the wafer is held against the chuck by vacuum. The groove plate, the stamp, the wafer, and the chuck function as one monolithic body at this point. Usually, after the imprint and stamp release sequence, the chuck is lowered, in this case by the chuck actuator and the main actuator. At this time, the chuck is raised and the actuator loses contact.

[0199] In such a case, the gap between the actuator tip 902 and the stopper 950 can have a dimension of, for example, 2 mm to 8 mm. The chuck can drop down by approximately 0.5 mm to 2 mm if it drops suddenly. This results in an impact having a collision force of approximately 5000 N on the actuator. As a result of this impact, the force sensor fails and the spindle of the actuator is damaged.

[0200] Raising the chuck requires protecting the groove plate from an overly large load. The main actuator 640 can easily cause too much tensile force by the stamp on the groove plate. Therefore, by detecting the sticky stamp, the main actuator can be stopped. Thus, the groove plate is protected from damage.

[0201] FIG. 16 shows an end view of a chuck driver 910 attached between a lever and a chuck. The chuck driver 910 has a cross-flexure portion 960 in the middle of its width (e.g., perpendicular to the Z axis). This enables any rotational movement in the width direction of the chuck driver, for example, rotation around the Y axis in the illustrated example.

[0202] The purpose of this movement is to enable the chuck driver 910 to take an appropriate position after the inclination of the chuck is adjusted.

[0203] The chuck driver 910 includes a shortened compensating leaf spring.

[0204] When the lever rotates about the pivot 912, the right side (the shorter side) of the lever becomes shorter as seen from the center of the chuck. This shortening is a parasitic motion of the lever. The length projected onto the plane of the chuck is shortened such that the length is L(l - cos(φ)), where φ is the rotation angle of the lever. For this reason, the lever component is compensated so that the positions of the chuck in the X-axis direction and the Y-axis direction do not change according to the adjustment of the position in the Z-axis direction.

[0205] This design enables the three chuck actuators to move individually over the full stroke of the lever. This enables zeroing the output of each actuator and prevents overconstraining the chuck.

[0206] The forces applied to the chuck in the X-axis direction and the Y-axis direction (parallel to the wafer) are routed through the cross-flexure portions 912 of the three levers and the cross-flexure portion 960 of the chuck driver 910. Each lever thereby provides two degrees of freedom, translation along the Z-axis and the X-axis.

[0207] The short-stroke manipulator design is used as a chuck actuator for the movement of the chuck and also as a landing ring actuator for the movement of the stamp landing ring. Therefore, two short-stroke manipulators, one constituting the chuck actuator and the other constituting the landing ring actuator, can be arranged at each corner of the triangular sub-frame 600. This provides a modular design.

[0208] In this design, it should be noted that the tension spring 906 not only pulls the sensor tip towards the lever but also pulls the actuator tip towards the stopper. However, two separate springs can be used. This means that the load on the sensor is not (or is less) affected by adjusting the pre-tension of the tension spring and / or by different positions of the lever.

[0209] As described above, another aspect of the present invention is the ability to control the position of the stamp landing ring. Some further improvements regarding the stamp landing ring are discussed below.

[0210] As explained above, before starting the imprint process, the substrate (wafer) is brought very close to the stamp, for example, to 25 μm to 300 μm, creating a process gap. The grooves of the groove plate are continuously pressurized, causing the stamp to bulge from the groove plate towards the substrate and reach the process gap until it contacts the substrate and is supported by the substrate. During contact, the resist layer on the substrate solidifies, and after such solidification, the stamp is removed by supplying a vacuum to the grooves again. Thus, the process of applying the stamp to the substrate uses the pressure difference between the area of the stamp held by the groove plate and the area pushed towards the substrate. Such a difference occurs at the edge of the stamp. The difference is a cause of pressure leakage, and as a result, the stamp application and / or removal may become uncontrolled. Generally, the larger the process gap between the groove plate and the substrate (or chuck), the greater the leakage and the accompanying pressure loss under the stamp. Therefore, the process gap needs to be accurately controlled across the entire area of the stamp.

[0211] The various stamps vary from one edge to the other. In the support (groove plate), there are regions that are not covered by the stamp material at the edge. Therefore, since only the wafer and the stamp being supported are in contact in this region, it is not supported during the stamping operation. This lack of support enables the stamp to bulge beyond the set process gap in these regions, which may cause further leakage.

[0212] The above-described stamp landing ring surrounds the chuck so as to provide stamp support in this edge region, and thus can prevent the entire flexible stamp region from bulging beyond the set process gap. However, various combinations of the stamp and the substrate (wafer) require various thicknesses and gaps that are actively controlled, involving different regions outside the stamp and different stamp thicknesses.

[0213] The stamp landing ring is a further edge support structure, and this edge support structure prevents the stamp at the edge from bulging beyond the set process gap by supporting the components of the composite stamp.

[0214] Figure 17 shows a process using a stamp landing ring.

[0215] The above description shows a substrate 180 that is raised higher than the chuck 500 by supporting the wafer lift pin 1000, and a chuck separated from the groove plate 102 to which the stamp 106 is attached. The chuck 500 is driven with respect to the chuck assembly, such as the sub-frame 600, by the chuck actuator 620a.

[0216] The stamp landing ring 502 is driven with respect to the sub-frame 600 by the landing ring actuator 620b.

[0217] The configuration above enables the loading and unloading of the substrate 180 and the stamp 106.

[0218] The imprint position is shown below.

[0219] The process gap between the substrate 180 and the stamp 106 is the same as the process gap between the stamp landing ring 502 and the groove plate (or more specifically, the glass support plate of the stamp) outside the region where the stamp material is present.

[0220] The use of separate chuck actuators and landing ring actuators allows for various combinations of the thickness of the substrate (wafer) and the thickness of the stamp.

[0221] Furthermore, additional improvements discussed below allow for various imprint configurations for various combinations of the stamp size (in plan view) and the wafer size (in plan view), for example, combinations of 200 mm or 300 mm substrates and 200 mm or 300 mm stamps.

[0222] Figure 18 shows the substrate 180 supported by the chuck 500. The stamp landing ring 502 supports an area outside the actual stamping area. Figure 18 shows the stamp landing ring adapter 1002 on top of the stamp landing ring. The adapter design has the same shape and size as the stamp landing ring, thus providing thickness compatibility. For example, Figure 18 shows a 300 mm wafer 180 together with a 300 mm PDMS stamp 106. The process gap is defined by the distance between the wafer, the stamp, the adapter 1002, and the thin glass support of the stamp.

[0223] However, the stamp landing ring adapter may also employ a stamp landing ring that depends on the size of the substrate.

[0224] FIG. 19 shows a stamp landing ring 502 for fitting around a substrate of a first size (e.g., 300 mm), and a stamp landing ring adapter 1002 for expanding the size of the stamp landing ring 502 to fit around a substrate 180 of a smaller second size (e.g., 200 mm).

[0225] In FIG. 19, the stamp landing ring 502 is for fitting around a flexible stamp 106 of a first size (e.g., 300 mm), and the stamp landing ring adapter is also for expanding the size of the stamp landing ring to fit around a flexible stamp 180 of a smaller second size (e.g., 200 mm).

[0226] Thus, FIG. 19 shows a 200 mm substrate (wafer) with a 200 mm PDMS stamp. The process gap is defined by the distance between the wafer, the stamp, the adapter, and the thin glass. The adapter extends above the 300 mm chuck and beyond the 300 mm chuck to support the PDMS stamp outside the wafer area. Since the ring is relatively thin, it can bend downwards due to the pressure under the stamp. This can be compensated by moving the stamp landing ring upwards relative to the chuck.

[0227] FIG. 20 shows an example where a chuck 500 is for fitting around a flexible stamp 106 of a first size (e.g., 300 mm), and there is a second stamp landing ring 1004 that fits around a substrate 180 of a smaller second size on the chuck.

[0228] Figure 20 shows that a 300 mm PDMS stamp is to be used on a relatively thin wafer (e.g., 200 - 300 μm). The overhanging stamp landing ring may not have a bending stiffness high enough to compensate for the pressure applied by the stamp. The maximum thickness for such a stamp landing ring is the wafer thickness.

[0229] The stamp bends the free - hanging part too much downward, so that the stamp does not transfer well onto the wafer, causing imprint defects at or around the wafer edge and stamp / pattern deformations that reduce overlay alignment.

[0230] By having a second stationary stamp landing ring as shown around the wafer, which has the same thickness as the substrate (wafer), the changes in stamp thickness and wedge due to chucking can be compensated using the movable stamp landing ring 502, and the whole stamp remains properly suspended over the entire area. The stationary ring 1004 does not need to be changed as the wafer thickness is usually within + / - 10 μm or even + / - 25 μm where it is not a problem, and the stamp can transition smoothly from the stationary ring 1004 to the wafer.

[0231] Figure 21 shows an example suitable for imprinting a relatively thick 200 mm wafer (e.g., 0.5 - 2 mm) using a 300 mm stamp, and thus the stamp also needs to be thick accordingly. The stamp landing ring adapter 1002 can have a stiffness sufficient to dampen the pressure from the stamp on the overhanging part. Still, the outer rubber region of the stamp needs to be supported so that the stamp does not bulge further than the process gap. This can be achieved by using a stamp landing ring with two thicknesses. The additional outer thickness provided by the second adapter 1006 compensates for the stamp thickness.

[0232] The adjustable drive provided by the landing ring actuator reduces the need to replace the stamp landing ring to account for various combinations of stamp and substrate. This enables (on-the-fly) adjustment for a wide variety of wafer thicknesses, stamp thicknesses, and wedge angles, resulting in an imprint process optimized for each case.

[0233] The optimized process gap results in a reduction in pressure loss and an improvement in the reproducibility of the imprint quality with reduced pattern distortion and improved overlay alignment.

[0234] For example, since it is desirable for the process gap to be defined within approximately a 10 μm range, the known thicknesses need to be within this range. Using the same tool and stamp hardware and size, various combinations of wafer size and stamp size can be handled.

[0235] The chuck actuator and the landing ring actuator enable dynamic changes to the gap between the stamp and the substrate at separate stages of the process (e.g., alignment, imprint, release).

[0236] The printing process requires loading the stamp onto the groove plate. In existing machines, the stamp is loaded by pivoting and opening the upper cover that holds the groove plate. The cover can be manually rotated 180° so that the groove plate is turned over and present. The stamp can then be placed with the glass plate side on the groove plate. The groove has a small overpressure at this point, thereby forming an air bearing for the stamp. Thus, the stamp can be easily moved and aligned manually.

[0237] Next, the position is fixed by switching the groove to vacuum. After that, the cover can be closed again and the imprint process can be started. In case of power down or vacuum loss, the stamp drops onto the chuck. To remove the stamp, the upper cover can be easily opened manually in the same way.

[0238] The design described above with a groove plate alignment stage for overlay alignment and wafer size increase means that having a pivotable cover is not desirable as it is overly large, overly heavy, and overly fragile.

[0239] Therefore, another design aspect relates to a semi - automatic stamp loading function that loads the stamp from under the groove plate. The design approach described below also means that in case the holding of the stamp is lost (due to power loss or vacuum loss), the machine does not need to be opened. An integrated stamp drop protection prevents the stamp from dropping, and the stamp can be unloaded by the normal unloading sequence.

[0240] Figure 22 shows a design using semi - automatic stamp loading.

[0241] Figure 22 shows a groove plate 102 above a stamp 104. The stamp 104 is attached to a stamp carrier 1100 positioned in a frame, particularly a sliding telescopic drawer 1102. Both the stamp carrier 1100 and the drawer are considered to include a stamp loader. The stamp carrier 1100 includes a frame with a central opening to avoid contact with the rubber stamp material (PDMS). Thus, the stamp carrier 1100 supports the glass substrate of the stamp, and the stamp does not move or sink as the outer rim of the stamp is held by vacuum. The telescopic drawer 1102 moves the stamp carrier 1100 horizontally from the load position (outside the module) to the park position and then to the move position.

[0242] The long-stroke driver 640 of the module described above is used for the vertical lifting of the stamp carrier 1100.

[0243] The stamp 104 is shown above the chuck 500 and the stamp landing ring 502. The stamp landing ring is positioned by the stamp landing actuator 620a, and the chuck is positioned by the chuck actuator 620b.

[0244] This stamp loading mechanism automatically loads and unloads the stamp 104 from below without opening the upper cover. The groove plate 102 is positioned by downward grooves. A stamp drop protection part 1104 is also integrated inside the frame of the groove plate 102.

[0245] The stamp 104 is held by vacuum on the outer rim of the stamp carrier 1100 by the vacuum channel 1101. The stamp carrier 1100 has, for example, two separate vacuum channels. One channel is used when the carrier is placed in the telescopic drawer 1102, and the other channel is used when the stamp carrier is placed on the stamp landing ring 502. The presence of the stamp is detected by measuring the vacuum pressure.

[0246] Here, the stamp loading sequence will be described. (i) The operator opens the door of the module. (ii) The operator pulls out the telescopic drawer 1102 to the loading position outside the module. (iii) Place the stamp carrier 1100 in the drawer mechanism. (iv) The operator manually places the stamp on the stamp carrier 1100. Thus, steps (i) to (iv) include loading the stamp onto the stamp carrier of the drawer (stamp loader) when the stamp is located outside the imprint position. (v) The first vacuum channel of the vacuum channel 1101 provided by the drawer 1102 holds the stamp in place. Thus, the suction channel of the stamp carrier is used to hold the stamp on the stamp carrier. (vi) The operator manually pushes the drawer to the park position and closes the machine door. (vii) A pneumatic cylinder or other actuator pulls the drawer to the transfer position. The transfer position is above the stamp landing ring 502 and the chuck 500 and below the groove plate 102 as shown in FIG. 22. Thus, this involves moving the stamp loader (drawer and stamp carrier) into the space between the first carrier and the second carrier. (viii) Raise the long stroke driver 640 that supports the chuck 500 and the stamp landing ring 502 until the stamp landing ring 502 touches the stamp carrier 1100. The three support pins of the stamp carrier 1100 are centered in the three holes or slots of the stamp landing ring (which can be seen in FIG. 22). This involves moving the stamp carrier and the held stamp towards the first carrier by moving the second carrier towards the first carrier. (ix) The second vacuum channel of the vacuum channel 1101 provided by the stamp landing ring takes over the clamping of the stamp, and the first vacuum channel can be switched off. (x) The long stroke driver 640 raises the stamp carrier 1100 a few millimeters above the drawer mechanism. Thereby, the stamp carrier 1100 moves from the telescopic drawer 1102 to the stamp landing ring 502. (xi) The drawer mechanism returns from the transfer position to the park position by a pneumatic cylinder or other actuator to prevent a collision with the long stroke driver 640. (xii) The long-stroke driver 640 raises the stamp carrier directly below the groove plate 102. At this point, the stamp drop protection part 1104 is active (open). Thus, the held stamp is moved to the first carrier (groove plate). (xiii) Switch the groove of the groove plate 102 to vacuum so that the stamp 104 is held by the groove plate 102. Thus, there is a transfer of the held stamp to the groove plate (first carrier). (xiv) Switch off the second vacuum channel of the stamp carrier. (xv) Next, the long-stroke driver 640 lowers the stamp carrier 1100 to the transfer height. This separates the second carrier (chuck) from the first carrier (groove plate). (xvi) Next, the stamp drop protection part 1104 is either maintained in a functional state or made non-functional (closed). The stamp drop protection part 1104 can be maintained in a functional state because it does not interfere with the descending stamp carrier 1100 at that point. (xvii) Move the drawer 1102 by a pneumatic cylinder or other actuator to return it under the stamp carrier 1100, that is, to the transfer position. (xviii) Lower the long-stroke driver 640 until the carrier 1100 is supported by the drawer. A clearance of several millimeters is required. (xix) Retract the drawer to its park position by a pneumatic cylinder. Thus, move the stamp loader to return it to a position outside the imprint position that can be the parking position.

[0247] Next, the loaded stamp is ready for use. The stamp is unloaded by the reverse procedure.

[0248] The integrated stamp drop protection part prevents the stamp from falling uncontrollably onto the chuck.

[0249] Typically, three or four clamps support the stamp at the corners or outer rim of the stamp. The stamp drop protection part includes, for example, a spring force biasing mechanism to keep the stamp in a clamped state in case of loss of power, vacuum or air pressure. As outlined above, the stamp drop protection part needs to be opened to load and unload the stamp. In the closed (clamped) position, the stamp drop protection part gets in the way of the stamp carrier.

[0250] During normal manufacturing cycles (i.e., without stamping), the stamp drop protection part remains closed (i.e., clamped). The stamp drop protection part is designed not to get in the way of the stamp landing device during normal cycles. Openings inside or around the stamp landing ring can be used to allow any movement (linear and rotational) of the clamp.

[0251] If the stamp is not fixed to the groove plate (due to an accident, etc.) and is only clamped by the stamp drop protection part, the stamp can be removed by performing the normal stamp unloading sequence by the stamp carrier. Manual intervention by the operator (opening the module as has been done so far) is not required.

[0252] The stamp load process is described as semi-automatic in that the stamp is manually loaded into the drawer. However, the drawer design can be used as a step towards full automation of stamp loading and unloading in the future. Currently, the operator manually places the stamp on the carrier, and the telescopic drawer moves the carrier in and out. In the future, this could be done by a robot in the cluster tool. This could be the robot currently used to load and unload wafers or an additional robot. The end effector of the robot needs to be able to handle the stamp carrier and provide a vacuum to hold the stamp. In that case, the robot can take over the role of the drawer. Inside the cluster tool, a stacking system can be installed to accommodate the stamp carrier with the new stamp loaded and the empty stamp carrier.

[0253] There are various design aspects described above. They can be used alone or in combination. In particular, these design aspects are as follows. Drive of the Z-axis movement of the chuck in two stages by a separate long-stroke driver and short-stroke driver. This enables the formation of a very rigid support. Use of a lever component for the chuck actuator and / or the stamp landing ring actuator. The lever component enables an improvement in positioning accuracy and an increase in rigidity compared to direct control of the position using the actuator output. A chuck including a hollow cylindrical body having an upper surface and a lower surface, and a lattice configuration between the upper surface and the lower surface. The chuck has a reduced thermal mass while maintaining the required rigidity to maintain a uniform imprint gap. Use of a landing ring actuator to translate a part of the stamp landing ring in the Z-axis direction. In addition to the movement of the chuck, the movement of the stamp landing ring enables the apparatus to take into account various stamp thicknesses. An interface plate to be mounted on a chuck having a pressurized cavity to enable double-sided printing. A stamp support system for enabling semi-automatic (or fully automatic) stamp loading. Division of position control between these two to enable full 6DOF control while allowing sufficient rigidity between the stamp carrier and the groove plate carrier.

[0254] In the above example, the first carrier includes an array of apertures used to draw the flexible stamp towards the first carrier and to push the flexible stamp away from the first carrier. A pressure source combined with the apertures provides an actuator function. However, other actuators may be used, for example, an electromagnetic actuator or other actuator may be used to provide the push-pull function.

[0255] It should be noted that the above-described embodiments are illustrative rather than limiting the present invention, and those skilled in the art can design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claims. The words "comprising" and "having" do not exclude the presence of elements or steps other than those listed in the claims. A singular element does not exclude the presence of a plurality of such elements. The present invention can be implemented by hardware including several distinct elements. In a device claim listing several means, some of these means can be embodied by exactly the same item of hardware. The mere fact that certain means are described in mutually different dependent claims does not indicate that a combination of these means cannot be used advantageously.

Claims

1. a first carrier carrying a flexible stamp; a second carrier movable relative to the first carrier; An imprinting apparatus comprising: wherein the second carrier includes: a chuck carrying a substrate having a resist layer; a set of chuck actuators for translating a part of the chuck in a direction perpendicular to the plane of the second carrier, each chuck actuator including a chuck driver, an actuator output portion, and a lever configuration portion between the actuator output portion and the chuck driver; In an imprinting apparatus including: The lever configuration portion includes a first pivot between a fixed lever portion and a movable lever portion, and a distance between the first pivot and the chuck driver is shorter than a distance between the first pivot and the actuator output portion, so that a vertical displacement of the chuck driver is smaller than a vertical displacement of the actuator output portion. An imprinting apparatus characterized by this.

2. The imprinting apparatus according to claim 1, wherein the first pivot includes a flexible pivot between the fixed lever portion and the movable lever portion.

3. The imprinting apparatus according to claim 1 or 2, wherein the chuck driver includes a second pivot where the chuck driver connects to the movable lever portion.

4. The imprinting apparatus according to claim 3, wherein the second pivot includes a flexible pivot.

5. The imprinting apparatus according to claim 1 or 2, wherein the lever configuration portion is biased toward a first holder by an adjustable spring configuration portion.

6. The imprinting apparatus according to claim 1 or 2, wherein the lever configuration portion includes a force sensor for monitoring a force transmitted through the lever configuration portion between the actuator output portion and the chuck driver.

7. The imprinting apparatus according to claim 6, wherein the lever configuration portion includes a split gap terminating at a notch flexure portion, and the force sensor is attached at the split gap.

8. a main frame; a main frame actuator for translating the main frame in a direction perpendicular to the plane of the second carrier. The imprinting apparatus according to claim 1 or 2, wherein the main frame actuator has a stroke larger than that of the chuck actuator.

9. The second carrier further includes a sub-frame, the sub-frame is connected to the main frame, the chuck is attached to the sub-frame, and the sub-frame is attached to the main frame by a spring component that biases the sub-frame against the first carrier via a kinematic coupling during imprinting. The imprinting apparatus according to claim 8.

10. The imprinting apparatus according to claim 1 or 2, wherein the chuck includes a set of position sensors that measure the distance from the surface of the chuck to the first carrier.

11. The imprinting apparatus according to claim 1 or 2, further comprising a stamp landing ring around the outside of the chuck, the stamp landing ring being for facing the first carrier outside the area of the flexible stamp.

12. The imprinting apparatus according to claim 11, wherein the second carrier includes a set of position sensors that measure the distance from the stamp landing ring to the first carrier.

13. The imprinting apparatus according to claim 11, further comprising a set of landing ring actuators, each having a third stroke smaller than the first stroke, for translating a part of the stamp landing ring in a direction perpendicular to the plane of the second carrier relative to the main frame.

14. The imprinting apparatus according to claim 1 or 2, wherein the chuck includes a hollow cylindrical body having an upper surface and a lower surface, and the upper surface and the lower surface each include an internal water channel configuration that provides a flow path between a set of water inlets and a water outlet.

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