Patent ID: 12242187

DETAILED DESCRIPTION

FIG.1illustrates an imprint lithography system100that forms a relief pattern on a substrate102. The substrate102may be coupled to a substrate chuck104. In some examples, the substrate chuck104includes a vacuum chuck, a pin-type chuck, a groove-type chuck, an electromagnetic chuck, or other appropriate chuck. Exemplary chucks are described in U.S. Pat. No. 6,873,087, which is hereby incorporated by reference herein. The substrate102and the substrate chuck104may be further supported by a stage106. The stage106provides motion about the x-, y-, and z-axes as well as rotation (e.g., θ) about the z-axis. In this regard, the stage106may refer to an XYθ stage. The stage106, the substrate102, and the substrate chuck104may also be positioned on a base (not shown).

The imprint lithography system100includes an imprint lithography template108that is spaced apart from the substrate102. In some examples, the template108includes a mesa110(mold110) that extends from the template108toward the substrate102. In some examples, the mold110includes a patterning surface112. The template108and/or the mold110may be formed from such materials including, but not limited to, fused-silica, quartz, silicon, organic polymers, siloxane polymers, borosilicate glass, fluorocarbon polymers, metal, hardened sapphire, or other appropriate material. In the illustrated example, the patterning surface112includes a plurality of features defined by spaced-apart recesses124and protrusions126. The pattern being formed as described above is for purposes of example only and any type of pattern may be represented on the patterning surface112. As such, the patterning surface112may define any pattern that forms the basis of a pattern to be formed, via imprint processing, on substrate102.

The template108may be coupled to a template chuck128. In some examples, the template chuck128includes a vacuum chuck, a pin-type chuck, a groove-type chuck, an electromagnetic chuck, or any appropriate chuck. Exemplary chucks are described in U.S. Pat. No. 6,873,087. In some embodiments, the template chuck128may be of the same type as the substrate chuck104. In other embodiments, the template chuck128and substrate chuck may be different types of chucks. Further, the template chuck128may be coupled to an imprint head130such that the template chuck128, the imprint head130, or both are configured to facilitate movement of the template108. Movement of the template108includes movement in the plane of the template (in-plane movement) and movement out of the plane of the template (out-of-plane movement) with respect to the template. In-plane movement includes translation of the template108in the plane of the template (e.g., in the X-Y plane as depicted inFIG.1) and rotation of the template in the plane of the template (e.g., in the X-Y plane and about the Z axis). Translation or rotation of the template108with respect to the substrate102may also be achieved by translation or rotation of the substrate. In-plane movement of the template108also includes increasing or decreasing a compression force on opposite sides of the template (e.g., with a magnification actuator) to increase or decrease dimensions of the template in the X-Y plane of the template. Mechanisms and control for applying and adjusting forces will be described below with respect toFIGS.3-10. Out-of-plane movement of the template108includes translation of the template along the Z-axis (e.g., to increase or decrease a force applied to the substrate via the template by increasing or decreasing the distance between the template and the substrate) and rotation of the template about an axis in the X-Y plane of the template. Rotation of template108about an axis in the X-Y plane of the template changes an angle between the X-Y plane of the template108and the X-Y plane of substrate102, and is referred herein to as “tilting” the template with respect to the substrate, or changing a “tilt” or “tilt angle” of the template with respect to the substrate. U.S. Pat. No. 8,387,482 discloses movement of a template via an imprint head in an imprint lithography system, and is incorporated by reference herein.

The imprint lithography system100may further include a fluid dispense system132. The fluid dispense system132may be used to deposit a polymerizable material134on the substrate102. The polymerizable material134may be disposed on the substrate102using techniques such as drop dispense, spin-coating, dip coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), thin film deposition, thick film deposition, or other appropriate method. In some examples, the polymerizable material134is disposed on the substrate102before or after a desired volume is defined between the mold110and the substrate102. The polymerizable material134may include monomers as described in U.S. Pat. No. 7,157,036 and U.S. Patent Application Publication No. 2005/0187339, both of which are incorporated by reference herein. In some examples, the polymerizable material134is disposed on the substrate102as a plurality of droplets136.

Referring toFIGS.1and2, the imprint lithography system100may further include an energy source138coupled to direct energy140along a path142. In some examples, the imprint head130and the stage106are configured to position the template108and the substrate102in superimposition with the path142. The imprint lithography system100may be regulated by a controller144in communication with the stage106, the imprint head130, the fluid dispense system132, the energy source138, or any combination thereof, and may operate on a computer readable program stored in a memory146.

In some examples, the imprint head130, the stage106, or both, vary a distance between the mold110and the substrate102to define a desired volume therebetween that is filled by the polymerizable material134. For example, the imprint head130may apply a force to the template108such that the mold110contacts the polymerizable material134. After the desired volume is filled by the polymerizable material134, the energy source138produces energy140, such as broadband ultraviolet radiation, causing the polymerizable material134to polymerize and to conform to the shape of a surface148of the substrate102and the patterning surface112, defining a polymeric patterned layer150on the substrate102. In some examples, the patterned layer150includes a residual layer152and a plurality of features shown as protrusions154and recessions156, with the protrusions154having a thickness t1 and the residual layer152having a thickness t2.

The above-described system and process may be further implemented in imprint lithography processes and systems referred to in U.S. Pat. No. 6,932,934, U.S. Patent Application Publication No. 2004/0124566, U.S. Patent Application Publication No. 2004/0188381, and U.S. Patent Application Publication No. 2004/0211754, all of which are incorporated by reference herein.

Imprint lithography substrates and templates may include corresponding pairs of alignment marks that allow real-time alignment of the template and the substrate. After the patterned template is positioned over the substrate (e.g., superimposed over the substrate), an alignment of the template alignment marks with respect to the substrate alignment marks is determined. Alignment schemes may include “through the mesa” (TTM) measurement of alignment errors associated with pairs of corresponding alignment marks, followed by compensation of these errors to achieve accurate alignment of the template and a desired imprint location on the substrate as disclosed in U.S. Pat. Nos. 6,916,585; 7,170,589; 7,298,456; and 7,420,654, all of which are incorporated by reference herein. Alignment errors may be caused by relative positioning of the substrate and the template, deformation of the substrate or the template, or a combination thereof. Alignment errors may also be caused by the introduction of vibration caused by one or more actions of the imprint lithography process and machinery that executes imprint lithography processes.

FIG.3illustrates a exemplary deformation mechanisms310and control system that selectively determines and applies control values that are sent, communicated or otherwise transmitted to each respective deformation mechanism310of the plurality of deformation mechanisms. These control signals cause the respective deformation mechanisms310to apply and modify compressive forces applied to the template108shown inFIG.1such that an imprint pattern112can form a better fit with the substrate102and transfer the imprint pattern112thereto. The deformation mechanism310may deform the pattern area112of the template108by applying forces to four side surfaces302a-302dof the template108. As shown herein, this exemplary embodiment includes 16 deformation mechanisms310. Each respective deformation mechanism310includes an actuator312connected to a contact portion314wherein the contact portion314contacts at least a portion of a template side302a-302dadjacent thereto. Each of the deformation mechanisms310are connected to the controller144(illustrated by the dashed lines). The controller144executes at least one control algorithm that selectively determines an amount of force to be applied by each of the individual deformation mechanisms310to the sides302a-302dof the template108in order to modify the shape thereof.

The controller144, as shown inFIG.1, includes at least one central processing unit (CPU) and memory and can execute instructions stored in the memory to perform one or more of the described operations and/or functions. The controller144is in communication with one or more memories (e.g., RAM and/or ROM) and, in some instances executes stored instructions to perform the one or more control operations. In other instances, the controller144may temporarily store data in the one or more memories that are used in calculation and generation of the various signals described hereinafter. As such, the controller144controls the system100ofFIG.1by using a computer program (one or more series of stored instructions executable by the CPU) and data stored in the RAM and/or ROM. Here, the controller144may include (or may be in communication with) one or more dedicated hardware or a graphics processing unit (GPU), which is different from the CPU, and the GPU or the dedicated hardware may perform a part of the processes by the CPU. As an example of the dedicated hardware, there are an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and a digital signal processor (DSP), and the like. In some embodiments, the controller144may be a dedicated controller. In others, the control system100may include a plurality of controllers that are in communication with one another and other components of the control system100to implement the operations described herein.

The connection between the controller144and each of the deformation mechanisms310enables one or more control signals (time series of control values) to be communicated to the respective deformation mechanisms310which control the actuators312to apply various levels of force to the sides302a-302dvia respective contact portions314. These control signals may be sent, transmitted, or otherwise communicated to each of the deformation mechanisms310via a wired or wireless communication pathway. The actuator312drives the contact portion314to cause force to be applied to a portion of the side of the template108adjacent thereto. While illustrated herein as two separate components, the actuator312and contact portion314may be formed integral with one another. The actuator312part of the deformation mechanism310may be any actuation mechanism including but not limited to pneumatic, piezoelectric, magenetostrictive, and voice coils. In one embodiment, the deformation mechanisms310are mounted to a frame and linked together via a linkage system such that control signals can be provided to the linkage system for controlling the movement and operation of the deformation mechanisms310.

Exemplary control algorithms include those which cause the deformation mechanism310to operate as a correction mechanism that physically deforms the template108by applying external forces from sides302a-302dof the template108. By applying these forces, a shape of the pattern area112is corrected such that a difference between the shape of the pattern (shot area) formed on the substrate and the shape of the pattern area112can be reduced. Thus, overlay accuracy of the pattern formed on the substrate and the pattern of the imprint material newly formed on the substrate can be improved. Exemplary components of the shape (including the size) of the pattern area112that can be controlled by the deformation mechanism310may include, for example, a magnification component, and a distortion component (for example, a component having a rhombic shape, a trapezoidal shape, or the like, or a component having a higher order).

It should be noted that the illustration of 16 deformation mechanisms as shown inFIG.3is done for purposes of example only and merely illustrates one possible embodiment. In other embodiments there may be N number of deformation mechanisms310where N is at least two. The number of deformation mechanism used may be determined based on the size of template and amounts of force desired to be applied to the various sides of the template. In one embodiment, there are an equal number of deformation mechanisms310on each side302a-302dof template108.

During the imprint process, operation of the deformation mechanisms310are cycled in an open loop whereby they are cycled from a first level of compressive force to a second level of compressive force and then back to a third level of compressive force. The second level of compressive force is an upper limit of compressive force defined by design of the deformation mechanism310. The first and third levels of compressive force are each lower than the second level and are determined by system design as per the compression needed to deform the template108to ensure proper fit of the template to the substrate such that the curable liquid resist applied can fill into all areas, voids, and air spaces before being cured. In one embodiment, the first level and third level represent substantially a same level of compressive force. In another embodiment, the first level and third level represent different levels of compressive force so long as each of the different levels are less than the upper limit defined by the second level. It is preferred to cycle from the second level to the third level because magnification control prior to dispensing of the resist (e.g., fluid fill (FF)) is more repeatable starting from a high compressive state. In an alternative embodiment, the second level of compressive force is a lower limit of compressive force defined by design of the deformation mechanism310and the first and third levels are above the second level. In an alternative embodiment, the second level of compressive force is a set of values in which one or more of the compressive forces of the deformation mechanisms310are not at their limits.

The problem with the cycling described above is it leads to unbalanced magnification forces that could result in template slippage causing a poor imprint on the substrate. These problems are caused by each of the deformation mechanisms310reaching the second level (e.g., upper limit) at different times and then each deformation mechanism310exiting the upper limit to cycle down to the third level (e.g., lower compressive state) at different times. The control algorithm according to the present disclosure provides a magnification force (Mag) scheme that uses individual ramp trajectories for each of a plurality of deformation mechanisms310(e.g., actuators) that calculates a final force value for each individual deformation mechanism310to be applied during the ramp up to the upper limit of compressive force so that all of the deformation mechanism reach the initial upper value time at the same time. This advantageously causes each of the plurality of deformation mechanisms to reach their upper limit of compressive force at the same time. The result is Mag force remains balanced and causes a smooth transition at an end of the Mag ramp period thereby reducing the risk that the template will slip out of position prior to dispensing and curing of the liquid curable resist to achieve pattern transfer.

FIGS.4-7illustrate various aspects of a control algorithm for controlling the Mag force applied by respective ones of the plurality of deformation mechanisms310to the template108by the plurality of deformation mechanisms. The algorithms described herein are executed by the controller144shown inFIGS.1and3. Each controller144may comprise a series of stored instructions that are executed by the CPU of controller144to perform the described functions. In other embodiments, each controller described herein may be embodied as individual integrated circuits each with their own CPUs and memories and are dedicated to performing the processing associated therewith. In other embodiments, one or more of the controllers described herein may be embodied as a single integrated circuit. Further, in some embodiments, some of the described controllers may be dedicated processing units and be in communication with the CPU of the controller which is executing stored instructions to complete the function operations described herein.

FIG.4illustrates an algorithm for a Mag control sequence for use in an imprint lithography process. In operation, the Mag control sequence ensures that forces are applied to the template before the template is caused to be contacted to the substrate. In exemplary operation, the liquid curable resist is generally dispensed on a particular field of the substrate being imprinted prior to the Mag control sequence being performed. However, that need not be the case so long as the Mag force applied by the deformation mechanisms310are applied prior to the template contacting the substrate.

In summary operation, the process calculates and runs force trajectories for each of the plurality of deformation mechanisms (also known as “fingers”). The final force trajectory that is to be supplied by each deformation mechanism310to a portion of the side of the template108is calculated using a plurality of distortion parameters and a force correction matrix. A form of secondary deformation may be provided via a secondary deformation mechanism that is controlled based on one or more secondary deformation value(s) applied during the closed loop control magnification trajectory final forces that are used in the ramping targets at fluid fill start time. The secondary deformation mechanism is a type of deformation mechanism other than deformation mechanism310. This secondary deformation mechanism may provide a spatio-temporal adjustable distribution of heat to one or both of the substrate and template causing a spatially varying thermal expansion as described in U.S. Pat. Nos. 9,823,562 and 9,927,700 which are hereby incorporated by reference. The heat may be supplied by an LED or laser modulated by spatial light modulator. The secondary deformation mechanism may also include a zone type substrate chuck (otherwise known as substrate holding unit or substrate holder) with a plurality independently controllable zones (otherwise known as regions or concave portions) to independently control the pressure (positive or negative) applied to each zone as described in US Patent Publications Nos. 2019/0310547 and 2020/0183270 which are hereby incorporated by reference. In this way all forces applied by the deformation mechanisms310will enter and leave saturation (e.g., either their upper limit of compressive force or the lower limit of compressive force) at the same time, based on individually calculated finger ramp trajectories. Moreover, the calculated force trajectories will not exceed the saturation level (upper or lower) at any time.

In one embodiment, the algorithm uses five distortion parameters (e.g. set points) including values associated with a magnification force in the X direction (MagX), a magnification force in the Y direction (MagY), a skew parameter (Skew), trapezoidal distortion in the X direction (TrapX) and trapezoidal distortion in the Y direction (TrapY). In one embodiment, each value for each distortion parameter represents a trajectory.

Turning now toFIG.4, the imprint process starts at S400. In step S402, the algorithm sets distortion parameter (ForceSetpts) values associated with an initial distortion parameter values associated with a first state (DispenseMagSetpts) representing the dispense magnification state beginning at time=0. The dispense magnification state is the state of the deformation mechanisms310while droplets136are being dispensed by the fluid dispense system for the field about to be imprinted. In an alternative embodiment, the dispense magnification state is the state of the deformation mechanisms310after the template108has separated from the previous field that was imprinted and prior to the template contacting the current field to be imprinted. In one embodiment, in this first state, the set points would be associated with high compressive force for MagX and MagY and the setpoint values for Skew, TrapX, and TrapY are typically 0. In step S404, a distortion mechanism310force trajectory time value is set as configured. This represents an amount of time for each distortion mechanism310to reach the upper limit compression force. In step S406, the algorithm sets secondary deformation values for to zero. Steps S402-S406represent an initialization period prior to the first field on the substrate being imprinted with a pattern on the template.

At this time, the algorithm, in S408, executes a magnification control subtask which is further described inFIG.5. The magnification control subtask starts at S500. In step S502, the initial distortion parameter values are converted by calculation into force values by using a correction matrix. The correction matrix is a transformation matrix having a size equal to a number of distortion parameters by a number of distortion mechanisms310in the system. In an exemplary embodiment, the number of distortion parameters is five and a number of distortion mechanisms310is 16 such that the correction matrix is a 5×16 matrix and may be calculated in parallel as described in U.S. Pat. No. 7,768,624 the disclosure of which is incorporated herein by reference in its entirety. The force values calculated in S502are done on a per distortion mechanism310basis such that the number of force values calculated in S502equals the number of distortion mechanisms310in the system. In step S504, a secondary deformation value is added to each calculated force value. In one embodiment, the secondary deformation values are based on a calibration process associated with the particular substrate being imprinted based on the measurement of the substrate. In another embodiment, these values predefined based on the type of substrate. Exemplary types of secondary deformation mechanisms and values used in controlling them are described in U.S. Pat. No. 9,594,301 the disclosure of which is incorporated herein by reference in its entirety. Thereafter, in step S506the calculated force values for each distortion mechanism310are limited by minimum and maximum force limits associated with the distortion mechanism310such that the calculated force value cannot be below a minimum force value to be applied by the distortion mechanism310and it cannot exceed a maximum force value to be applied by the distortion mechanism310. The maximum force value to be applied represents the upper limit compressive force value the is defined by design of the system.

In step S508the subtask queries whether one or more setting values have changed. In one embodiment, the algorithm queries whether there has been a change in final force trajectory values for one or more distortion mechanisms310. In another embodiment, the algorithm queries whether there has been a change in ramp duration time. In another embodiment, the algorithm performs each of the above queries in succession. If the result of the query is yes indicating that there has been a change in setting values (either force values or ramp duration values), the algorithm performs, in S509a first function call “ramp_init_start_time” which sets the various force and time parameter values to be used. The first function call which configures a ramp trajectory for a respective one of the plurality of distortion mechanisms310with a given start force, final force, start time, and ramp is illustrated inFIG.6. As shown inFIG.6, the first function call takes, as inputs, identifiers identifying the particular distortion mechanism310with which the setting values are associated. The setting values include a starting force value, a final force value, a current time and a ramp time. This results in each of these values being set for use by the system to control the force to be applied by the distortion mechanisms310. Returning back to S508inFIG.5, after the first function call of S509, the algorithm performs a second function call S510to identify, for each distortion mechanism310, a force value to be applied at the given time. The second function call which is called iteratively during the ramping time to calculate the force value setpoints for respective distortion mechanisms310for the given elapsed time within the ramp period is illustrated inFIG.7. As shown inFIG.7, the second function call takes, as inputs, identifiers identifying the particular distortion mechanism310and a current time value to determine the force value to applied to and associated with a particular one of the plurality of distortion mechanisms310. The second function call determines whether a current time value is earlier than a start time value and if so, the starting force value set during the first function call is used and associated with the respective distortion mechanism310being checked. If the current time is not earlier than the start time, the second function queries whether the current time value is later than or equal to the set final time (e.g. end time), then a final force value set during the first function call is returned and used for the respective distortion mechanism310being checked. If the second function determines that the current time not later than or equal to the final time, the force value to be associated with the respective distortion mechanism310being checked is calculated according to the following equation:
(Start Force)+(Current Time−Start Time)×((Final Force−Start Force)/(Ramp Time))

The result of the second function in S510yields force value set points for each of the plurality of distortion mechanisms310such that, when applied, each distortion mechanism310will enter and exit the next phase of imprint processing together thereby reducing template imbalance. In step S512, the respective force values for each of the plurality of distortion mechanisms310are set thereby replacing any previously stored distortion mechanism310force value and the subtask ofFIG.5ends in S514returning us back to the algorithm ofFIG.4.

Upon completion of the subtask in S408, the algorithm queries the current operational state at the current time in S410. More specifically, S410queries whether the system is in the CL1 state indicating a time at which the template is compressed according to the individual force compression values set during the dispense magnification period and the template first contacts the polymerizable material134on the substrate102and the template may be bowed out by back pressure applied to a center portion of the template108by the template chuck128. During the CL1+CL2 period, the individual distortion mechanisms310ramp down from the upper limit compression force value which all distortion mechanisms310were ramped up to at the same time. During the CL1 phase, the individual distortion mechanisms310are controlled to ramp down the force applied to the template to allow for dynamic spread of the formable material134to the edge of the imprint field. At the end of CL1 is the CL2 phase where the imprint force and back pressure are quickly relaxed to their fluid fill (FF) force and back pressure values which allows the polymerizable material134to fill into remaining spaces, voids and other areas defined by the template.

The above operations are performed in steps S412-S418. More specifically, in S412distortion parameter values, which in some embodiments, include control bias force values are used in the calculation of final force trajectories for each of the particular deformation mechanisms310. The control bias force values are set according to the particular characteristics of the particular imprint process. The control bias force values are a component that is used in determining of the final target forces which are the forces supplied by the plurality of distortion mechanisms310at the beginning of the closed loop control of the magnification (CLCM). The force applied by each of the distortion mechanisms310is reduced from the upper limit compressive force value to predefined force levels whereby each of the plurality of distortion mechanisms310begin the reduction of applied force at the same time. In S414, the force trajectory time for each of the plurality of distortion mechanisms310is set to a time equal to a time for the CL1 phase plus a time for the CL2 phase and in S416, secondary deformation value(s) for each of the plurality of distortion mechanisms310are set according to the particular characteristics of the imprint process. In S418the Mag Control Subtask is reinitiated and operates as discussed above with respect to S408with the only difference being the ramping for each of the plurality of distortion mechanisms310begins at the same start time and the force values are iteratively reduced during a Ramp Time from the upper limit of compressive force (Start Force[16]) to arrive at the predefined force values (Final Force[16]) at the same end time. In an alternative embodiment, S418the Mag Control Subtask may be reinitiated the ramping for each of the plurality of distortion mechanisms310begins at the same start time and the force values are iteratively changed during a Ramp Time from a set value of compressive force (Start Force[16]) to arrive at the predefined force values (Final Force[16]) at the same end time (final time).

At the conclusion of S418, the algorithm, in step S420queries, using current time values whether the CL1 and CL2 periods have ended indicating that the process has entered the fluid fill (FF) phase. If not, the mag control subtask is repeated and the individual distortion mechanisms310are continually individually ramped to their final target forces until such time that the query in S420indicates that the imprint process has entered the fluid fill phase. At this point the algorithm shuts off the individual control of the distortion mechanism310and initiates the closed loop control of the magnification force (CLCM) to be applied by the distortion mechanisms310during the FF phase. During the FF phase the curable liquid resist fills in all open spaces and voids around and between the template and substrate. As such, in step S422, the CLCM is engaged and the trajectory time for each distortion mechanism310is set to zero so that alignment of the template to the substrate can be performed before the pattern is cured on the substrate. The alignment processing and CLCM processing is executed in S424and can be performed using any known alignment algorithm for imprint lithography processing. Step S424may include active measurement of the alignment template relative to the substrate which includes the measurement of a plurality of alignment marks as described in US patent publication No. 2020/0379343 which is hereby incorporated by reference. Step S424may include calculation of an overlay error between the current field being imprinted on the substrate102and a mesa110on the basis of results detected by a plurality of alignment scopes. Each alignment scope may be set up to measure a relative position of an alignment mark set including: a substrate alignment mark and a template alignment mark. There are at least 2 alignment mark sets and there may be as many as 4, 6, 8, 16, 24, or 30 alignment mark sets. The plurality of relative positions are then used to estimate alignment errors (shift in x; shift in y; rotation) and deformation components which may include 2 or more of: MagX; MagY; Skew; TrapX; TrapY: and other components having a higher order representing potential distortion of the template. Further examples of the processes performed in S424regarding alignment processing are described in U.S. Pat. Nos. 7,828,984, 8,845,317, 9,579,843 and 9,573,319 all of which are incorporated herein by reference and CLCM processing are described in U.S. Pat. Nos. 10,635,072 and 10,216,104, all of which are incorporated herein by reference.

The algorithm in step S426queries whether the imprint of a current field has been completed. If not, the algorithm returns back to S424. If the imprint on a particular field is completed, the algorithm determines, in S428, whether one or more other fields on the substrate need to be imprinted. If the determination in S428indicates that one or more other fields are available for imprinting, the algorithm returns to S402. If not, the imprint sequence ends at430. The impact of the Mag control subtask ofFIG.5(and associated function calls inFIGS.6&7) when incorporated into the imprinting algorithm ofFIG.4is illustrated in the graphical plots ofFIGS.8-10and the advantages conferred thereby can be understood in the comparison ofFIGS.8-10with exemplary prior art distortion application control illustrated inFIGS.11-13. Specifically,FIG.8illustrates the setting of the distortion parameters values which are stepped. As shown inFIG.8, the values for the respective distortion parameters are stepped and all changed at a given time depending on the particular phase of the imprint process. This stepped setting of the values for the distortion parameters allows for the calculation to run force trajectories for each of the plurality of distortion mechanisms310by using the stepped value set as shown inFIG.8and determining the force trajectory by combining the stepped values for each of the distortion parameters with the correction matrix. For example, the distortion parameters are set at a first value during the dispense magnification control phase until it is changed to a second lower value at a start of the CL1 phase of the imprint process. As a result of the independent control of each of the distortion mechanisms310, they all have individual force trajectories that allow them to ramp up to and arrive at an upper limit all at the same time and remain there until a start of the CL1 phase whereby force trajectories for each of the plurality distortion mechanisms310begin the ramp down process from the upper limit at the same time until the beginning of the fluid fill (FF) phase. This independent ramping of respective distortion mechanisms310reaching the upper limit is illustrated in the circle labeled902inFIG.9and the simultaneous exit from the upper limit beginning the ramp down at the start of the CL1 phase is illustrated in the circle labeled904inFIG.9. Because the distortion mechanisms310are individually controlled such that their individual force trajectories are calculated using the five distortion parameter setpoints in combination with the correction matrix which takes into account these five distortion parameters and the force trajectories of each of the other distortion mechanisms310and without the application of secondary deformation value(s), it all allows for each of the distortion mechanisms310to reach the upper limit at the same time and then exit the upper limit at the same time. Because all of the distortion mechanisms310arrive and leave the upper limit at the same time magnification forces remain balanced so as to not induce template slip and high-order Mag distortions. This balance is illustrated inFIG.10wherein there is substantially no deviation beyond the zero value indicating that magnification forces remain balanced across all phases indicated inFIG.10.

The advantages provided by the control algorithm described herein are clear when looking at the plots ofFIGS.11-13which illustrate the same periods illustrated inFIGS.9-11but using a convention distortion control method. The distortion control method used herein ramps the distortion parameter values over the same periods, taking into account the secondary distortion supplied by the secondary deformation mechanism. These are then applied equally to control the distortion members in unison as shown inFIG.11. The drawbacks of this type of control algorithm is shown inFIG.12whereby in the circle labeled1202, each of the distortion members arrive at the upper limit at different time periods and also exit the upper limit at different time periods as shown in the circle labeled1204. The impact on this is imbalance which can induce template slip and high order distortion. This resulting balance of magnification forces across the distortion members are shown inFIG.13which illustrates large distortion of magnification forces in different periods of the imprint process. Moreover, the imbalance differs depending on which phase of the process leading to further chances of template slippage prior to fluid fill phase and high order distortion errors.

As discussed above with respect toFIGS.8-10, the control algorithm described above inFIGS.4-7provide for individualized control of distortion members to enter and exit upper limit compressive force levels as the same time resulting in improved balance of magnification forces which minimize the change for template slippage and an improvement to the imprint lithography process.

A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

An embodiment of the present disclosure can be carried out by providing a program implementing one or more functions of the above-described embodiment to a system or apparatus via a network or storage medium and reading and executing the program with one or more processors in a computer of the system or apparatus. Also, an embodiment of the present disclosure can be carried out by a circuit implementing one or more functions (for example, an application specific integrated circuit (ASIC)).

Embodiment(s) of the present disclosure can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.

In referring to the description, specific details are set forth in order to provide a thorough understanding of the examples disclosed. In other instances, well-known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily lengthen the present disclosure.

It should be understood that if an element or part is referred herein as being “on”, “against”, “connected to”, or “coupled to” another element or part, then it may be directly on, against, connected or coupled to the other element or part, or intervening elements or parts may be present. In contrast, if an element is referred to as being “directly on”, “directly connected to”, or “directly coupled to” another element or part, then there are no intervening elements or parts present. When used, term “and/or”, includes any and all combinations of one or more of the associated listed items, if so provided.

Spatially relative terms, such as “under” “beneath”, “below”, “lower”, “above”, “upper”, “proximal”, “distal”, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the various figures. It should be understood, however, that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, a relative spatial term such as “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90° or at other orientations) and the spatially relative descriptors used herein are to be interpreted accordingly. Similarly, the relative spatial terms “proximal” and “distal” may also be interchangeable, where applicable.

The term “about,” as used herein means, for example, within 10%, within 5%, or less. In some embodiments, the term “about” may mean within measurement error.

The terms first, second, third, etc. may be used herein to describe various elements, components, regions, parts and/or sections. It should be understood that these elements, components, regions, parts and/or sections should not be limited by these terms. These terms have been used only to distinguish one element, component, region, part, or section from another region, part, or section. Thus, a first element, component, region, part, or section discussed below could be termed a second element, component, region, part, or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an”, and “the”, are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that the terms “includes” and/or “including”, when used in the present specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof not explicitly stated.

The foregoing merely illustrates the principles of the disclosure. Various modifications and alterations to the described exemplary embodiments will be apparent to those skilled in the art in view of the teachings herein.

In describing example embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner.