Method for improving accuracy of imprint force application in imprint lithography

Abstract

To improve the accuracy of final imprint force application in imprint lithography.SOLUTION: An imprint method includes the steps of: actuating an imprint head 30 along a preconditioning trajectory before bringing the imprint head into contact with a formable material 34 on a substrate 12; and performing imprinting on the formable material after actuating the imprint head. The step of actuating the imprint head along the preconditioning trajectory may be executed after the imprint head is idled for a predetermined period of time. The step of actuating the imprint head along the preconditioning trajectory may be executed for a duration determined based on expected throughput requirements and tools used for imprint processing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates to imprint lithography, and more particularly to methods for improving the accuracy of final imprint force application in imprint lithography. [Background technology]

[0002] Nanofabrication involves the fabrication of extremely small structures, with features on the order of 100 nanometers or less. One application in which nanofabrication has had a significant impact is the manufacture of integrated circuits. Nanofabrication is becoming increasingly important as the semiconductor processing industry continues to strive for greater production yields while increasing the circuits formed per unit area on a substrate. Nanofabrication provides greater process control while enabling a continued reduction in the minimum feature dimensions of the structures being formed.

[0003] One nanofabrication technique in use today is commonly referred to as imprint lithography. Imprint lithography is useful in a variety of applications, including, for example, forming one or more layers of an integrated device by molding a film on a substrate. Examples of integrated devices include, but are not limited to, CMOS logic, microprocessors, NAND flash memory, NOR flash memory, DRAM memory, MRAM, 3D cross-point memory, Re-RAM, Fe-RAM, STT-RAM, MEMS, and the like. Exemplary imprint lithography systems and processes are described in detail in numerous publications, such as U.S. Pat. No. 8,349,241, U.S. Pat. No. 8,066,930, and U.S. Pat. No. 6,936,194, all of which are incorporated herein by reference.

[0004] The imprint lithography techniques disclosed in each of the above patents involve forming a relief pattern in a layer of (polymerizable) formable material and transferring a pattern corresponding to the relief pattern into and / or onto an underlying substrate. The substrate can be coupled to a motion stage to obtain the desired positioning to facilitate the patterning process. The patterning process uses a template spaced apart from the substrate and a formable liquid supplied between the template and the substrate. The formable liquid is solidified to form a solid layer having a pattern that matches the shape of the surface of the template in contact with the formable liquid. After solidification, the template is separated from the solidified layer to separate the template and the substrate. The substrate and solidified layer are then subjected to additional processes, such as an etching process, to transfer a relief image into the substrate that corresponds to the pattern in the solidified layer. The patterned substrate can then undergo further known steps and processes for device fabrication, including, for example, oxidation, film formation, deposition, doping, planarization, etching, formable material removal, dicing, bonding, packaging, etc. Summary of the Invention

[0005] An imprinting method is provided, the method comprising: moving an imprint head along a preconditioning trajectory before contacting the imprint head with a formable material on a substrate; and imprinting the formable material after moving the imprint head. Moving the imprint head along the preconditioning trajectory can be performed after the imprint head has been idle for a predetermined period of time. Moving the imprint head along the preconditioning trajectory can be performed for a duration determined based on expected throughput requirements and the tool used for the imprint process.

[0006] The imprint method may include determining the preconditioning trajectory based on a history of position trajectories of the imprint head in previous imprint processes, an idle period after the previous imprint process and before starting to imprint the formable material, a predicted imprint position trajectory of the imprint head used to imprint the formable material, and an objective to be minimized. The objective may be determined based on a tool used for imprinting, process force behavior for imprinting, and force stability requirements during imprinting. The objective may include minimizing sudden changes in average disturbance forces acting on a first and second substrate during a run, or variations in stress relaxation disturbances across all substrates during the run.

[0007] In one embodiment, the preconditioning trajectory can be identified as a plane that results in a decrease in a user-defined metric during imprinting of the formable material. The imprint head idle plane can be determined using a historical position trajectory of an imprint head template used to imprint the formable material, a predetermined model of disturbance forces, and a predicted imprint position trajectory of the template. The metric can include any of: a change in cable relaxation force averaged across a substrate, a change in cable relaxation force across multiple substrates across different force calibration routines, or a variation in cable relaxation force in a first imprint area across different substrates. A final imprint force for imprinting the formable material can be estimated based on a measured overlay error and the preconditioning trajectory selected to minimize the variation in the final imprint force across multiple substrates or to minimize the difference in final imprint force between a first substrate and a second substrate.

[0008] A method for manufacturing an article is also provided, comprising: moving an imprint head along a preconditioning trajectory before contacting a template with a formable material dispensed onto a substrate; holding the template by the imprint head; dispensing the formable material onto the substrate; moving the imprint head to bring the template into contact with the formable material; and then imprinting the formable material with a final imprint force adjusted in real time.

[0009] These and other objects, features, and advantages of the present disclosure will become apparent from a reading of the following detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings and the appended claims. [Brief explanation of the drawings]

[0010] In order that the features and advantages of the present invention may be better understood, a more particular description of the embodiments of the present invention will be made by reference to the embodiments illustrated in the accompanying drawings, which should be noted, however, that the accompanying drawings illustrate only typical embodiments of the present invention and therefore should not be considered as limiting the scope of the present invention, since the present invention may admit of other equally effective embodiments.

[0011] [Figure 1] FIG.

[0012] [Figure 2] FIG. 10 illustrates the sudden change in final imprint force between processing a first and second substrate, and the drift in force after processing the second and subsequent substrates.

[0013] [Figure 3] FIG. 10 shows a comparison of the position trajectories of the imprint head in various time ranges for two different preconditioning plane determinations in different time ranges t1 and t2 with the original position of the imprint head without preconditioning.

[0014] [Figure 4A] FIG. 1 illustrates a method for obtaining an optimal trajectory for the imprint head (tool and process). [Figure 4B] FIG. 1 illustrates a method for obtaining an optimal trajectory for the imprint head (tool and process).

[0015] [Figure 5] FIG. 10 is a diagram showing the position trajectory of the imprint head with a preconditioning trajectory.

[0016] Throughout the drawings, the same reference numerals and characters, unless otherwise stated, are used to denote like features, elements, components, or portions of the illustrated embodiments. Moreover, while the present disclosure will be described in detail with reference to the figures, it is done so in connection with the exemplary embodiments. It is intended that changes and modifications can be made to the exemplary embodiments described without departing from the true scope and spirit of the subject disclosure, as defined by the appended claims. DETAILED DESCRIPTION OF THE INVENTION

[0017] Nanoimprint System 1 shows an imprint lithography apparatus 10 in which embodiments can be implemented. The apparatus 10 can be used to form a relief pattern on a substrate 12. The substrate 12 can be coupled to a substrate chuck 14. As shown, the substrate chuck 14 is a vacuum chuck. However, the substrate chuck 14 can be any type of chuck, including, but not limited to, a vacuum chuck, a pin-type chuck, a groove-type chuck, an electrostatic chuck, an electromagnetic chuck, etc.

[0018] The substrate 12 and the substrate chuck 14 may be further supported by a positioning stage 16. The stage 16 may provide translational and / or rotational motion along one or more of the x-axis, y-axis, z-axis, θ-axis, and Φ-axis. The stage 16, the substrate 12, and the substrate chuck 14 may also be positioned on a base (not shown).

[0019] Spaced apart from substrate 12 is template 18. Template 18 includes a body having a first side and a second side, one side having a mesa 20 (also referred to as a mold 20) extending therefrom toward substrate 12. Mesa 20 may have a patterned surface 22 thereon. Alternatively, template 18 may be formed without mesa 20.

[0020] Template 18 and / or mold 20 may be formed from materials including, but not limited to, fused silica, quartz, silicon, organic polymers, siloxane polymers, borosilicate glass, fluorocarbon polymers, metals, hardened sapphire, and the like. As shown, pattern surface 22 includes features defined by a plurality of spaced recesses 24 and / or protrusions 26, although embodiments of the present invention are not limited to such structures (e.g., a flat surface). Pattern surface 22 may define any master pattern that forms the basis for a pattern to be formed on substrate 12. Alternatively, pattern surface 22 may be blank, i.e., devoid of pattern features, in which case a flat surface may be formed on the substrate. In an alternative embodiment, if pattern surface 22 is the same area size as the substrate, a layer may be formed across the entire substrate (e.g., the entire substrate process).

[0021] The template 18 may be coupled to a template chuck 28. The template chuck 28 may be configured as, but is not limited to, a vacuum chuck, a pin-type chuck, a groove-type chuck, an electrostatic chuck, an electromagnetic chuck, and / or other similar types of chucks. The template chuck 28 may be coupled to an imprint head 30. The imprint head 30 is movably coupled to a bridge 36 such that the template chuck 28, imprint head 30, and template 18 are movable in at least the z-axis direction.

[0022] Apparatus 10 may further include a fluid dispensing system 32. Fluid dispensing system 32 may be used to deposit a formable material 34 (e.g., a polymerizable material) on substrate 12. Formable material 34 may be disposed on substrate 12 using techniques such as drop dispensing, spin coating, dip coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), thin film deposition, thick film deposition, etc. Formable material 34 may be disposed on substrate 12 before and / or after a desired volume is defined between mold 22 and substrate 12, depending on design considerations.

[0023] Fluid dispensing system 32 can use different technologies to dispense formable material 34. If formable material 34 is jettable, an inkjet-type dispenser can be used to dispense the formable material. For example, thermal inkjet, microelectromechanical system (MEMS)-based inkjet, valve jet, and piezoelectric inkjet are common technologies for dispensing jettable liquids.

[0024] Apparatus 10 may further include a radiation source 38 that directs actinic energy 40 along path 42. Imprint head 30 and stage 16 may be configured to position template 18 and substrate 12 in superposition with path 42. Camera 58 may likewise be positioned in superposition with path 42. Apparatus 10 may operate according to a computer-readable program stored in memory 56, coordinated by a processor 54 in communication with stage 16, head 30, fluid dispensing system 32, source 38, and / or camera 58.

[0025] The imprint head 30, the stage 16, or both vary the distance between the mold 20 and the substrate 12 to define a desired volume therebetween to be filled with the moldable material 34. For example, the imprint head 30 can apply a force to the template 18 so that the mold 20 contacts the moldable material 34. After the desired volume is filled with the moldable material 34, the radiation source 38 generates actinic energy 40 (e.g., ultraviolet light) that hardens the moldable material 34. This causes the moldable material 34 to conform to the substrate surface 44 of the substrate 12 and the patterned surface 22 of the template 18, solidifying and / or crosslinking and defining a shaped layer on the substrate 12. In one embodiment, the substrate 12 can be a substrate, an unpatterned template, or some other object onto which the moldable material 34 is molded by the template 18.

[0026] Stress relaxation model During the imprint process, a contact force acts on the formable material on the substrate at the end of the curing process, before the substrate and template are separated. A contact force is also applied to the formable material on the substrate while the formable material is spreading before curing. In one embodiment, the substrate can be a semiconductor wafer, a blank template, or some other object onto which the formable material 34 is molded by the template 18. This contact force applied at the end of curing is called the final imprint force (FIF). The final imprint force is one of the key parameters that needs to be controlled with high precision on the tool, for example, to an accuracy of 0.01, 0.05, 0.1, 0.5, or 1 N (Newton), to achieve target overlay specifications for nanoimprint lithography. Measuring this final imprint force during the imprint process is extremely challenging because a contact-based force sensor can intrude into the imprint process, significantly affecting alignment, overlay, and other process specifications. Imprint systems are force-controlled with FIF during contact; therefore, direct estimation of the applied force based on an estimate of the current through the voice coil may not capture the true force acting on the formable material due to disturbances, for example, from cable stress relaxation. Currently, the final imprint force can be estimated by calibrating the non-contact imprint force at a set position and then estimating the total final imprint force imparted by the actuator, for example, through a commanded current flowing through the imprint head voice coil. However, it has been observed that non-contact force calibration is not always accurate or repeatable under external disturbances that violate target specifications across multiple imprint areas on multiple substrates, thereby degrading overlay performance. As the imprint head 30 moves from one non-contact position to another, the position may settle within a short period of time, but the force (current) through the voice coil actuator continues to decay to maintain a constant non-contact position, and the magnitude of that decay may be greater than the target specification.The rate and magnitude of this force decay behavior can vary over time, depending on the initial conditions of the system and the state of disturbance sources (e.g., cable stress). It has been found that this variation can be due to the development and relaxation of stresses in the cables and tubing attached to the imprint head 30 (z-head) as the imprint head 30 moves between different positions during the imprint process. The stress relaxation behavior has been found to be motion profile dependent and can depend on many factors, such as the step size between the initial and final positions, the velocity of the imprint head 30 while moving from the initial to final positions, and the overall prior state of the cables and tubing, including the initial stresses in the cables and tubing. For example, the imprint head 30 may spend time idling in a non-optimal plane, i.e., a plane where the cables and tubing connected to the imprint head 30 are not relaxed, thereby generating stresses in the cables and tubing attached to the imprint head 30's moving body prior to imprinting.

[0027] When the imprint head 30 begins an imprint process after an idle period, e.g., a long period of no imprint head 30 movement, the time constant of cable stress dynamics in the imprint head can range from a few seconds to tens of minutes (depending on the cable management quality). Therefore, stress relaxation dynamics affect the force behavior as the imprint head 30 goes through its imprint routine across a series of substrates. This affects the stability of the final imprint force and subsequently the overlay stability across multiple substrates. The greatest impact of stress relaxation is observed in the early time range after the idle period, manifested by a sudden jump in the average final imprint force applied by the imprint head 30 on the imprint of the second substrate in the series compared to the average final imprint force applied to the first substrate. For example, as shown in Figure 2, the average estimated final imprint force (extracted from the overlay data after the imprint process) changes suddenly from the processing of the first substrate to the processing of the second substrate. After the processing of the second substrate, the final imprint force slowly drifts from the imprint force applied in the processing of the second substrate. The average estimated final imprint force for a particular substrate can be determined by first estimating the final imprint force used to imprint each imprint area on the particular substrate based on overlay data. For each imprint area on the particular substrate, overlay data is measured at multiple locations within the imprint area after imprinting. This overlay data is then fitted to a process variation model. The process variation model may be based on one or more experimental and simulation methods, such as finite element analysis, finite difference analysis, finite volume analysis, and other computational methods that describe how variations in a set of shaping conditions affect variations in the quality of the imprinted film. U.S. Patent Application Publication No. 2019 / 0033709-A1 (incorporated herein by reference) describes how this variation in a set of shaping conditions affects variations in the quality of the imprinted film and how this variation can be simulated.The set of molding conditions that can be simulated by the process variation model includes a final imprint force used at the end of or during the curing period, along with other molding conditions. A first set of these other molding conditions may be controlled using the positioning system, such as shifts along one or more perpendicular axes, rotations about one or more axes, tilts about one or more axes, and rotations about one or more axes. A second set of these molding conditions may be associated with the thermal radiation source and / or finger subassembly, such as expansions along one or more axes, keystone distortions along one or more axes, and skews along one or more axes.

[0028] The underlying physics of stress relaxation in the cable or tube can be used to establish a dynamic model of stress relaxation in the cable or tube to estimate the force disturbance at any time based on the prior motion history of the imprint head. The dynamic model can be expressed in the following form: x'(t) = Ax(t) + Bu(t) f d (t) = Cx(t) + Du(t) or f d (t) = g(x(t),x'(t),u(t),t) where x(t) is the M state variables of the model, u(t) is the imprint head position at a certain time (t), x'(t) is the time derivative of the state variable x(t), and f d (t) is the instantaneous force disturbance, e.g., due to cable relaxation. This model is typically derived: the model parameters A (M×M matrix), B (M×1 matrix), C (1×M matrix), and D (1×1 matrix) are estimated using the position u(t) and force (a function of the commanded force supplied by the actuator) traces of the imprint head 30, typically during a previous calibration routine or imprint. The estimated disturbance force f dTo obtain (t), the static force contributions from known stiffness elements in the imprint head positioning system, such as flexures and springs, are calibrated out from the total force trace estimated from the commanded current supplied to the actuator. Finding the model parameters involves applying the above dynamic model to the force disturbance estimates f from the test. d This can include fitting the (t) trace to the imprint head 30. Once the model parameters, i.e., matrices A, B, C, and D, for a linear model or nonlinear function have been identified and the model has been found to be appropriate and robust, the model can be used to predict force disturbances, for example, due to cable relaxation, as the imprint head 30 passes through its motion before, during, and after the imprint process, even if no direct control over this force disturbance exists using existing techniques. During the imprint process, one or more encoders can be used to indicate the position of the imprint head 30. The position based on actuator feedback control can be used to control the movement of the imprint head 30 during part of the imprint process. During curing, the force that the pattern surface 22 applies to the moldable material 34 can also be controlled by adjusting the force supplied by the actuator using force-based feedback control. To accurately control the final imprint force exerted by the pattern surface on the moldable material, the force supplied by the actuator can be adjusted to the predicted disturbance force f d (t) must be taken into account.

[0029] Optimal trajectory / path generation Preconditioning of the imprint head 30 can be used before starting actual imprinting to bring the imprint head from an idle state to a more repeatable and stable force behavior. An idle state is defined as a period during which the imprint head 30 is stationary / idling at a predetermined position along the z-motion axis and is not performing any operations related to actual imprinting or is preparing for a subsequent imprint (such as a metrology task before imprinting on a substrate). The idle time can be longer than the time required to imprint a single substrate. A preconditioning trajectory can be used before imprinting the first substrate in a series of substrates, or before each substrate in a series of substrates if the throughput requirements are low and can be met with a preconditioning trajectory before imprinting each substrate. As an example, if the time interval between imprinting two consecutive substrates exceeds 2-3 minutes, a preconditioning trajectory can be determined and added to the routine individually before imprinting each such substrate to meet the desired throughput constraints of the process. In other cases, when the time interval between two consecutive substrates is small, e.g., less than 1-2 minutes, using preconditioning before imprinting each substrate may not be efficient. "Preconditioning" refers to operating the imprint head through a trajectory to make its behavior more stable and repeatable before imprinting begins. As shown in Figure 3, the time range p0 is defined as the duration during which the imprint head 30 is idle in a given plane and may include a portion of the past imprint routine. It is expected that the past history or trajectory of the imprint head 30 at p0 is available, or the model obtained above can be used to estimate the state x(t) and the force disturbance f. dThe imprint process may include identifying an optimal preconditioning trajectory for the imprint head 30. The optimal preconditioning trajectory is determined during time p0 while tracking (t). The length of time range p0 is preferably at least as long as the longest time constant determined for the cable stress relaxation model. That is, information on the imprint head 30's motion history is desired for at least as long as the longest time constant in the model. Time range p1 indicates the optimization time range or length of the preconditioning routine, which can vary depending on process requirements, such as process throughput requirements, and can vary from process to process. Time range p2 indicates the actual imprint routine for a single substrate or series of substrates. The imprint process may include identifying an optimal preconditioning trajectory for the imprint head 30. The optimal preconditioning trajectory is determined during time range p1 using the imprint head's past trajectory, i.e., the trajectory during p0, and a predicted estimate of the trajectory during the actual imprint, i.e., the trajectory during p2, and a predetermined model of disturbance forces, such as cable stress dynamics, to minimize an objective function. The objective function for optimization may be different objectives depending on the requirements for tool and process force behavior and force stability during imprint, i.e., during time range p2. For example, the objective function may be the average force disturbance across the substrate between the first and second substrate |f Wafer1 -f Wafer2 The mean force disturbance f of the substrate i may include minimizing sudden changes in | Waferi is calculated for each imprint area j over a curing period t as described by the following equation: j,FIF In an alternative embodiment, f d (t j,FIF ) is the average predicted force disturbance during the curing period.

number

[0030] Another example of an objective function is to minimize the standard deviation σ of the mean force disturbance fluctuation in imprinting across all subsequent substrates, i.e., the mean force f across Q substrates, as described in the following equation: Waferi The goal is to minimize σ of

number

[0031] Alternatively, the weighted sum (w1|f Wafer1 -f Wafer2 |+w2σ) or (w1(f Wafer1 -f Wafer2 ) 2 A custom objective function such as (w + wσ) can be defined to stabilize a particular force behavior of the imprint head 30. Another measure can be to minimize the variation in cable stress relaxation force over a force calibration routine, which can be performed once before imprinting for each substrate. Note that depending on the definition of the objective function, the expected nominal position profile of the imprint head during imprint, i.e., the position profile at p, may be required for optimization before the actual imprint.

[0032] The imprint head motion trajectory u(t) in the time range p1 is calculated by minimizing the objective function, e.g., minimizing |f Wafer1 -f Wafer2 |, i.e., the minimized force disturbance abruptness between the first and second substrates is found with the following constraints: x'(t) = Ax(t) + Bu(t) (1) f d (t) = Cx(t) + Du(t), (2), or f d (t) = g(x(t),x(t),u(t),t) (3), where u(t) = [-800μm, 300μm] where x(t) are the M state variables of the model, u(t) is the imprint head position at a time, and f dis the force disturbance due to stress relaxation of the cable. The minimum and maximum motion limits of the imprint head may be limited to between -800 μm and 300 μm depending on the imprint head design, such as the imprint head's motion range specifications, space, and safety constraints. These motion limits are exemplary and may vary from one imprint head to another depending on where the zero of the imprint head's motion is set / defined, as long as the motion range is determined to be within the hardware's motion range specifications. Various numerical techniques, optimization algorithms, and solvers are available to solve the optimization problem described above, including Pontryagin's maximum principle, constrained optimization using various tools, such as FMINCON (a MATLAB® function), constrained linear optimization, IPOPT (a Python library), NLOPT (an open-source library for nonlinear optimization), genetic algorithms, and pattern search. Once the problem is properly formulated and the constraints are defined, an optimal solution can be obtained that minimizes the objective while satisfying the constraints. Figure 5 shows an example problem using position traces from an actual imprint run set up in MATLAB® and using FMINCON to identify an optimal solution over a time horizon p1 to minimize the variation in force disturbances over the next 10 substrates. A preconditioning trajectory is found over a preconditioning period t2 that minimizes the objective. This preconditioning trajectory or solution can be used over time horizon p1 prior to starting the imprint routine on a substrate or series of substrates.

[0033] In one embodiment, the optimization problem can be modified to identify a preconditioning plane solution u0 instead of a time-varying trajectory u(t) over time range p1. A preconditioning plane solution may be more desirable compared to a time-varying trajectory solution, with points of smaller velocity, acceleration, and jerk changes to the imprint head motion, and may be easier to implement using hardware and software compared to a more complex time-varying trajectory (one position identification for a plane versus 1000 seconds of intermediate position point identification for a time-varying trajectory has computationally fewer parameters to identify). As an example, a preconditioning trajectory holds the imprint head 30 in a preconditioning plane position during time range p1, thereby also minimizing mean force disturbance variations from the first substrate to the second substrate and improving performance of the imprint process. Different planes were found for different preconditioning time ranges p1 and are listed in Table 1 (rows 3-7). For example, as shown in Figure 3, the imprint head is positioned at plane 1 and plane 2 for two different time ranges, t1 and t2, respectively. The objective function values ​​that minimize the mean force disturbance variation from the first substrate to the second substrate and the 3σ forces obtained from the sample trajectories are listed in Table 1. For reference, the performance of cycling trajectories in which the imprint head 30 cycles over a period of time is included in the second row of Table 1 for the no-preconditioning (row 1) and preconditioning optimal solutions. As can be seen from this table, all preconditioning solutions better minimize the objective (force disturbance variation from the first substrate to the second substrate) compared to the typical cycling solution for preconditioning. This preconditioning optimization also provides an interesting solution, finding that the objective function is minimized if the imprint head is idled at the (-212) μm plane for the entire idle duration.As shown in the table, when the imprint head is located in a different plane than plane z = 0 for the entire idle duration, the z = -212.1 μm plane provides the best force stability, both in terms of the force disturbance variation from the first substrate to the second substrate and the overall variation of the force disturbance for the imprint of the next 10 substrates. This indicates that the idle plane position of the imprint head should be set close to the (-212) μm plane, as the cables are least stressed when resting in that plane. [Table 1]

[0034] FIG. 4A illustrates a process flow of a method for obtaining an optimal trajectory for an imprint head (tool and process) in real time. In step S401, prior motion and force disturbance history is used to obtain a dynamic model for cable stress relaxation or other disturbances in the imprint head. The dynamic model may be of the form given by equations (1) and (2) or (3) above. In step S402a, a predicted position trajectory of the imprint head 30 for imprinting on multiple substrates is obtained based on the historical data, spread time, and other process variables. In other words, the predicted imprint head motion trajectory u(t) over time range p2 is estimated from the historical data, spread time, and other imprint process timing details, such as any measurement steps before imprinting on a substrate or measurements between successive imprints. In step S402b, either the position history of the imprint head during the time range p is available or it is assumed that a dynamic model of the cable relaxation is running in real time on the tool, and therefore it has knowledge of the motion trajectory, i.e., the imprint head 30 over u(t) during p, and can calculate the cable relaxation dynamics x(t) and the force disturbance magnitude f at any instant in time. dThe model has information about the state of (t) during p0. As mentioned previously, it is desirable that the model must have been running on the tool for at least the longest time constant or have information about the imprint head motion trajectory u(t) for that duration during p0. The duration of the time horizon for preconditioning, i.e., p1, before the first substrate in a series of substrates is determined taking into account the expected throughput requirements of the process, may vary from process to process and from tool to tool. As shown throughout FIG. 4B , in step S403, the objective function to be minimized is defined in step S403c, optimization constraints (based on tool hardware design, feasible trajectories, computational and time complexity, etc.) are provided in step S403b, information from steps S402a and S402b is fed to the model, and in step S403d, an optimizer / solver is run to obtain an optimal trajectory u(t) for preconditioning during time horizon p1 for a given expected imprint routine during time horizon p2 (obtained during step S403a). For real-time applications, it is expected that this optimization will be completed and the optimized preconditioning trajectory solution will be available before the start of the preconditioning time range p1. Thus, step 403b, which requires the imprint head position during p0, may involve a combination of the imprint head position history (for the time elapsed since the optimization routine started p0) and a predicted position trajectory of the imprint head for the remaining time in p0 (the imprint head position trajectory is known in advance with good accuracy and reliability). In step S404, the imprint head is moved along the trajectory during the preconditioning period p1, followed by imprint execution during period p2 in step S405.

[0035] In one embodiment, the preconditioning trajectory is performed only before starting imprinting on the first substrate in the series. In an alternative embodiment, the preconditioning trajectory is performed before every substrate in the series. In one embodiment, the preconditioning trajectory is generated before loading imprint parameters for the imprint process. In one embodiment, the preconditioning trajectory is generated during the imprint process. In one embodiment, the preconditioning trajectory is adjusted during the imprint process.

[0036] The optimization methods described above can be used not only to determine preconditioning routines, but also to optimize the imprint operation itself to reduce or minimize user-defined metrics / objectives, such as the variation in force disturbance over time. This variation can be due to cable stress relaxation. The optimization method can result in more stable force behavior. The optimization routine can also be used for other dynamic disturbances that affect stability on another subsystem to provide an optimal trajectory or path for preconditioning the system. The metric can include the mean force disturbance variation exerted by the template on the formable material on multiple substrates imprinted with the formable material.

[0037] Further modifications of the various embodiments and alternative embodiments will be apparent to those skilled in the art in light of the foregoing description. Accordingly, this description is to be construed as illustrative only. It is understood that the forms shown and described herein are to be construed as exemplary of embodiments. Elements and materials may be substituted for those shown and described herein, components and methods may be reversed, and certain features may be utilized independently, all as will become apparent to those skilled in the art after having the benefit of this description.

Claims

1. moving the imprint head along a preconditioning trajectory before contacting the imprint head with formable material on a substrate; imprinting the formable material after moving the imprint head along the preconditioning trajectory; and Moving the imprint head along the preconditioning trajectory is performed for a duration determined based on expected throughput requirements and the tool used for the imprint process. An imprint method comprising:

2. 2. The method of claim 1, wherein the step of moving the imprint head along the preconditioning trajectory is performed after the imprint head has been in an idle state for a predetermined period of time.

3. A method of manufacturing a substrate, comprising: moving an imprint head along a preconditioning trajectory before contacting the imprint head with a formable material on a substrate; imprinting the formable material after moving the imprint head along the preconditioning trajectory; and a history of the position trajectory of the imprint head in past imprint processes; an idle period after the previous imprinting operation and before the start of imprinting of the formable material; an expected imprint position trajectory of the imprint head used to imprint the formable material; and a target to be minimized; The imprint method further comprises determining the preconditioning trajectory based on the above.

4. 4. The method of claim 3, wherein the target is determined based on the tool used for imprinting, the process force behavior for imprinting, and force stability requirements during imprinting.

5. 4. The imprint method of claim 3, wherein the target includes minimizing sudden changes in average disturbance forces acting on the first and second substrates during a run, or variations in stress relaxation disturbances across all substrates during the run.

6. A method of manufacturing a substrate, comprising: moving an imprint head along a preconditioning trajectory before contacting the imprint head with a formable material on a substrate; imprinting the formable material after moving the imprint head along the preconditioning trajectory; and the preconditioning trajectory includes information regarding a plane of the imprint head that results in a decrease in a predetermined index while imprinting the formable material; The predetermined index is The variation of cable stress relaxation force averaged over one board across multiple boards; Variation of cable stress relaxation force across different force calibration routines and Variation in cable relaxation force in the first imprint area across different substrates; and Contains any of the An imprint method comprising:

7. A method for manufacturing a moldable material comprising: moving an imprint head along a preconditioning trajectory before contacting the imprint head with a moldable material on a substrate; imprinting the formable material after moving the imprint head along the preconditioning trajectory; and the preconditioning trajectory includes information regarding a plane of the imprint head that results in a decrease in a predetermined index while imprinting the formable material; a history of the position trajectory of an imprint head template used to imprint the formable material; and a predetermined model of the disturbance force; an expected imprint position trajectory of the template; and determining an idle surface of the imprint head using An imprint method comprising:

8. A method for manufacturing a moldable material comprising: moving an imprint head along a preconditioning trajectory before contacting the imprint head with a moldable material on a substrate; imprinting the formable material after moving the imprint head along the preconditioning trajectory; and A final imprint force for imprinting the formable material is estimated based on the measured overlay error and the preconditioning trajectory selected to minimize variation in the final imprint force across multiple substrates or to minimize a difference in final imprint force between a first substrate and a second substrate. An imprint method comprising:

9. 1. A method of manufacturing an article, comprising: holding the template with an imprint head; holding the template and moving the imprint head along a preconditioning trajectory before contacting the template with formable material dispensed onto a substrate; providing a formable material over the substrate; moving the imprint head to contact the template with the formable material; imprinting the formable material with a final imprint force adjusted in real time; and Moving the imprint head along the preconditioning trajectory is performed for a duration determined based on expected throughput requirements and the tool used for the imprint process. A method characterized by:

10. 10. The method of claim 9, wherein moving the imprint head along the preconditioning trajectory is performed after the imprint head has been idle for a predetermined period of time.

11. A method for manufacturing an article, comprising: holding the template with an imprint head; holding the template and moving the imprint head along a preconditioning trajectory before contacting the template with formable material dispensed onto a substrate; providing a formable material over the substrate; moving the imprint head to contact the template with the formable material; imprinting the formable material with a final imprint force adjusted in real time; and a history of the position trajectory of the imprint head in past imprint processes; an idle period after the previous imprinting operation and before the start of imprinting of the formable material; an expected imprint position trajectory of the imprint head used to imprint the formable material; and a target to be minimized; determining the preconditioning trajectory based on A method characterized by:

12. The method of claim 11 , wherein the target is determined based on the tool used for imprinting, the process force behavior for imprinting, and the force stability requirements during imprinting.

13. 12. The method of claim 11 , wherein the target includes minimizing sudden changes in average disturbance forces acting on the first and second substrates in a run or variations in stress relaxation disturbances across all substrates in the run.

14. A method of manufacturing an article, comprising: holding the template with an imprint head; holding the template and moving the imprint head along a preconditioning trajectory before contacting the template with formable material dispensed onto a substrate; providing a formable material over the substrate; moving the imprint head to contact the template with the formable material; imprinting the formable material with a final imprint force adjusted in real time; and the preconditioning trajectory includes information regarding a plane of the imprint head that results in a decrease in a predetermined index while imprinting the formable material; a history of the position trajectory of an imprint head template used to imprint the formable material; and a predetermined model of the disturbance force; an expected imprint position trajectory of the template; and determining an idle surface of the imprint head using A method characterized by:

15. A method for manufacturing an article, comprising: holding the template with an imprint head; holding the template and moving the imprint head along a preconditioning trajectory before contacting the template with formable material dispensed onto a substrate; providing a formable material over the substrate; moving the imprint head to contact the template with the formable material; imprinting the formable material with a final imprint force adjusted in real time; and the preconditioning trajectory includes information regarding a plane of the imprint head that results in a decrease in a predetermined index while imprinting the formable material; The predetermined index is The variation of cable stress relaxation force averaged over one board across multiple boards; Variation of cable stress relaxation force across different force calibration routines and Variation in cable relaxation force in the first imprint area across different substrates; and Contains any of the A method characterized by:

16. A method for manufacturing an article, comprising: holding the template with an imprint head; holding the template and moving the imprint head along a preconditioning trajectory before contacting the template with formable material dispensed onto a substrate; providing a formable material over the substrate; moving the imprint head to contact the template with the formable material; imprinting the formable material with a final imprint force adjusted in real time; and a final imprint force for imprinting the formable material is estimated based on a measured overlay error and the preconditioning trajectory selected to minimize variation in the final imprint force across multiple substrates or to minimize a difference in final imprint force between a first substrate and a second substrate.

Images