JP6609158B2 - Adjusting apparatus, imprint apparatus and article manufacturing method - Google Patents

Description

  The present invention relates to an adjustment apparatus, an imprint apparatus including the adjustment apparatus, and an article manufacturing method for manufacturing an article using the imprint apparatus.

  In addition to photolithography technology, semiconductor devices have become finer, and imprint materials are supplied onto the substrate. A mold (also called a template or mold) is brought into contact with the imprint materials, and the imprint materials are cured in this state. Processing technology is drawing attention. This technique is also called an imprint technique, and can form a fine structure on the order of several nanometers on a substrate. For example, one of the imprint techniques is a photocuring method. In the photocuring method, a material that is cured by light irradiation is used as the imprint material.

  When overlaying the pattern (underground) formed on the substrate and the pattern formed on the mold, first, the alignment system detects the relative position between the mark on the mold and the mark on the wafer, and drives the substrate. The shift and the shift in the rotation direction are corrected. Furthermore, pattern shape errors such as magnification, skew, trapezoid, bow, and thread winding are corrected by deforming the mold. In order to perform pattern superposition with high accuracy, a mechanism for deforming the mold with accuracy of several nanometers or less is required.

  In Patent Document 1, in order to deform a template, a plurality of pairs each including a series connection of a piezoelectric actuator and a piezoelectric sensor are provided between a template and a support structure disposed around the template. The arranged configuration is described. The force generated by the piezoelectric actuator is feedback controlled using the output of the piezoelectric power sensor.

  Patent Document 2 describes a system in which a plurality of actuators are disposed between a pattern forming device and a frame disposed around the pattern forming device in order to deform the pattern forming device (template). The plurality of actuators constitute a plurality of pairs arranged to face each other with the pattern forming device interposed therebetween. Each pair of actuators is controlled to generate forces that are opposite in direction and equal to each other so that the force in the x-axis direction, the force in the y-axis direction, and the moment about the z-axis are zero.

JP 2009-141328 A Japanese Patent No. 4573873

  In the system described in Patent Document 2, in a steady state in which an operation for applying a force to the pattern forming device to complete the deformation is completed, the force in the x-axis direction, the force in the y-axis direction, and the force around the z-axis are applied to the pattern forming device. The moment is considered to be zero. However, in the system, in a transient state in which the patterning device is deformed by applying force, for example, only one of the pair of actuators contacts the patterning device and the other does not yet contact the patterning device. A situation can occur. There may also be a difference in the response and characteristics of the pair of actuators. In such a case, in the transient state, the force in the x-axis direction, the force in the y-axis direction, and the moment around the z-axis that are applied to the pattern forming device exceed allowable values, and the pattern forming device is displaced and / or rotated. Can be caused. In addition, even at the moment when the pattern forming device is brought into contact with the imprint material on the substrate, the force in the x-axis direction, the force in the y-axis direction, and the moment around the z-axis exceed the allowable values. The device can be misaligned and / or rotated.

  An object of the present invention is to provide an advantageous technique for preventing the mold from being displaced and / or rotated when the mold is deformed.

  One aspect of the present invention relates to an adjusting device that adjusts the shape of a mold, and the adjusting device includes a plurality of forces that apply force to the mold in order to adjust the shape of the mold held by a mold holding unit. An actuator, a plurality of sensors for detecting a plurality of forces applied to the mold by the plurality of actuators, and a resultant force of the plurality of forces applied to the mold by the plurality of actuators based on outputs of the plurality of sensors And a control unit that controls a plurality of forces applied by the plurality of actuators to the mold so that the resultant force satisfies a restriction.

  According to the present invention, an advantageous technique is provided to prevent the mold from being displaced and / or rotated when the mold is deformed.

1 is a schematic diagram illustrating a configuration of an imprint apparatus according to an embodiment of the present invention. The figure which shows the structure of the adjustment apparatus which adjusts the shape of a mold. The figure which shows the structural example of the adjustment apparatus which adjusts the shape of a mold. The figure which shows the other structural example of the adjustment apparatus which adjusts the shape of a mold. The figure which shows the structural example of a feedback compensator. The figure which illustrates the characteristic of a filter. The figure which illustrates the characteristic of an output limiter.

  Hereinafter, the present invention will be described through exemplary embodiments thereof with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram illustrating a configuration of an imprint apparatus 1 according to an embodiment of the present invention. The imprint apparatus 1 causes the pattern portion P of the mold M to contact the imprint material (for example, resin material) supplied on the substrate S to cure the imprint material, thereby forming a pattern. Composed.

  In this specification and the accompanying drawings, the X axis (first axis) and the Y axis (second axis) that are orthogonal to each other in a plane parallel to the surface of the pattern portion P of the mold M, and the X axis and the Y axis are orthogonal to each other. The direction is indicated in the XYZ coordinate system in which the Z axis (third axis) is determined. In the XYZ coordinate system, the directions parallel to the X, Y, and Z axes are the X, Y, and Z directions, respectively, and rotation around the X axis, rotation around the Y axis, and rotation around the Z axis are θX and θY, respectively. , ΘZ. The control or drive related to the X axis, Y axis, and Z axis means control or drive related to the direction parallel to the X axis, the direction parallel to the Y axis, and the direction parallel to the Z axis, respectively. The control or drive related to the θX axis, θY axis, and θZ axis relates to rotation around an axis parallel to the X axis, rotation around an axis parallel to the Y axis, and rotation around an axis parallel to the Z axis. Means control or drive.

  The imprint apparatus 1 can include a substrate holding unit (substrate stage) 10 that holds the substrate S, and a substrate driving unit 12 that drives the substrate S by driving the substrate holding unit 10. Further, the imprint apparatus 1 can include a mold holding unit 20 that holds the mold M, and a mold driving unit 40 that drives the mold M by driving the mold holding unit 20. The substrate driving unit 12 and the mold driving unit 40 constitute a positioning mechanism that controls the relative position between the substrate S and the mold M. The positioning mechanism can control the relative position between the substrate S and the mold M with respect to the X axis, Y axis, Z axis, θX axis, θY axis, and θZ axis. Contact of the mold M with the imprint material supplied on the substrate S and separation of the cured imprint material and the mold M are performed by the positioning mechanism.

  In addition, the imprint apparatus 1 may include an adjustment device 30, a curing unit 50, an alignment measuring instrument 60, a dispenser 70, a base member 82, and a support structure 84. The adjusting device 30 can be configured to adjust the shape of the mold M. As shown in FIG. 2, the adjustment device 30 includes a plurality of actuators 32, a plurality of sensors 34, and a control unit 36. The plurality of actuators 32 can be supported by the support portion 31. The support part 31 can be supported by the mold holding part 20, for example. The plurality of actuators 32 may be configured to apply a force to the mold M in order to adjust the shape of the mold M held by the mold holding unit 20. The plurality of sensors 34 may be configured to detect a plurality of forces applied to the mold M by the plurality of actuators 32. The single actuator 32 and the single sensor 34 may be connected in series so that the single sensor 34 is disposed between the mold M and the single actuator 32.

  FIG. 2 shows an example in which 16 actuators 32 and 16 sensors 34 are provided as a more specific example. However, the number of actuators 32 and sensors 34 is arbitrary. As the actuator 32, for example, a piezo element having a small calorific value and excellent responsiveness can be used, but other elements may be used. The sensor 34 may be a load cell, a strain gauge, or the like, but other types of sensors may be used.

  The dispenser 70 supplies an imprint material on the substrate S. The curing unit 50 supplies energy for curing the imprint material to the imprint material on the substrate S, thereby curing the imprint material. For example, when the imprint is a photocurable material, the energy is light (eg, ultraviolet light). The mold M can be made of a material that transmits the energy. For example, when the energy is light, the mold M can be made of a light transmitting material such as quartz.

  The alignment measuring instrument 60 can include a measurement light source 62, an image sensor 64, and an optical system (not shown). For example, the alignment measuring device 60 irradiates the mark on the substrate S and the mark AM on the mold M with light from the measurement light source 62, and images the image formed by these marks with the image sensor 64. The relative position with respect to the mold M is detected. Based on this relative position, the relative position between the substrate S and the mold M is controlled by a positioning mechanism including the substrate driving unit 12 and the mold driving unit 40.

  On the other hand, shape errors between the shot region on the substrate S and the pattern portion P of the mold M, such as magnification, skew, trapezoid, bow, and thread winding, are reduced by deforming the mold M by the adjusting device 30. The shape target value of the mold M to be deformed by the adjusting device 30 may be determined based on the result of inspecting the imprint result on the test substrate, or may be determined based on the measurement result by the alignment measuring instrument 60. Also good.

  FIG. 3 is a block diagram illustrating a configuration example of the adjustment device 30. The adjusting device 30 includes a minor loop for controlling the force applied to the mold M and a major loop for controlling the resultant force applied to the mold M. Here, “combined force” means a combined force. The adjustment device 30 includes a control unit 36, a plurality (m) of drivers 130, a plurality (m) of actuators 32, a plurality (m) of transmission units 150, and a plurality of (m) sensors 34. Here, the transmission unit 150 is a transfer function that takes the force generated by the actuator 32 as an input and outputs the input to the sensor 34, in other words, a transfer function between the output of the actuator 32 and the input to the sensor 34. The control unit 36 may include a force target value generation unit 110, a plurality of (m) compensators 120, a resultant force calculator 170, a feedback compensator 180, a distributor 190, and a plurality (m) of calculators 200.

  The shape target value when the mold M is deformed can be supplied to the adjusting device 30 (control unit 36) as a deformation amount decomposed into a plurality of shape components such as magnification, skew, trapezoid, and bobbin. As described above, the shape target value may be determined based on the result of inspecting the imprint result on the test substrate, or may be determined based on the measurement result by the alignment measuring instrument 60.

  The force target value generation unit 110 generates a plurality of force target values that are target values of forces to be generated by the plurality (m) of actuators 32 based on the shape target values. Here, let a some force target value be f1-fm. m is the number of actuators 32 (number of axes). The shape target value is r1-rn. r1-rn is n shape components including magnification, skew, trapezoid and the like. The relationship between f1-fn and r1-rn is given by equation (1).

・・・（１）

... (1)

  (Amn) is a matrix composed of m × n elements. For example, the shape of the mold M in a state where no force is applied, the Young's modulus and Poisson's ratio of the material of the mold M, and the mold holding unit 20 This parameter is determined by the frictional force of the mold M against the holding surface. (Amn) can be determined through simulation or actual measurement. For example, the deformation of the pattern portion P when a compressive force corresponding to the force target value f1-fm is applied to the side surface of the mold M is calculated by a method such as the finite element method (FEA), and the shape components r1-rn are calculated. Can do. Such a calculation is performed on a plurality of sets of force target values f1-fm, and (Amn) can be determined by a process such as a least square method. Here, equation (1) corresponds to a linear simultaneous equation, but in order to perform shape correction with high accuracy, equation (1) may be developed to increase the order.

  The arithmetic unit 200 calculates a plurality (m) of force target values f1-fm based on the outputs of the plurality (m) of sensors 34 and the plurality (m) of force correction amounts cf1-cfm output from the distributor 190. Can be corrected. Specifically, the arithmetic unit 200 can include an adder 201 and a subtracter 202. The adder 201 can be configured to add a plurality (m) of force target values f1-fm and a plurality (m) of force correction amounts cf1-cfm output from the distributor 190. The subtractor 202 can be configured to calculate a deviation between the output of the adder 201 and the outputs af 1 -afm of the plurality (m) of sensors 34.

  The plural (m) compensators 120 generate plural (m) command values for the plural (m) drivers 130 based on the plural (m) outputs from the arithmetic unit 200. The compensator 120 can include, for example, a PID compensator and a filter (eg, a low-pass filter, a notch filter).

  The plural (m) drivers 130 drive the plural (m) actuators 32 based on the plural command values from the plural (m) compensators 120. Thereby, a plurality (m) of actuators 32 generate a force, and this force is applied to the side surface of the mold M, and the mold M is deformed. The plurality (m) of drivers 130 may be current amplifiers, for example. Forces generated by a plurality (m) of actuators 32 are detected by a plurality (m) of sensors 34 via a plurality (m) of transmission units 150 and output as a plurality of force measurement values af1-afm. . The i-axis compensator 120, the driver 130, and the actuator 32 operate based on the target force value fi, force measurement value afi, and force correction amount cfi, and the i-axis sensor 34 measures the force. The value afi is detected.

  The resultant force calculator 170 calculates the resultant force applied to the mold M according to the equation (2) based on a plurality (m pieces) of force measurement values af1-afm detected by the plurality (m pieces) of sensors 34. . The resultant force calculator 170 may be configured to calculate shift forces Fx, Fy and rotational force (moment) Frot as a resultant force (a force obtained by combining af1-afm), for example. Fx is a force synthesized in a direction parallel to the x axis, Fy is a force synthesized in a direction parallel to the y axis, and Frot is a rotational force (moment) synthesized around the z axis.

・・・（２）

... (2)

(B _3m ) is a matrix composed of 3 × m elements, and is determined by the geometrical arrangement of the action points of the force on the mold M by the mold M and the plurality of actuators 32. The feedback compensator 180 calculates shift forces Fx ′, Fy ′ and rotational force Frot ′ as feedback resultant forces based on Fx, Fy, and Frot. FIG. 5 shows a configuration example of the feedback compensator 180.

  The feedback compensator 180 can include at least one of an output limiter 183 and a filter 182 that limit the output of the feedback compensator 180. The feedback compensator 180 may include a PID compensator 181. In the example shown in FIG. 5, the feedback compensator 180 includes a PID compensator 181, a filter 182, and an output limiter 183. The filter 182 may include at least one of a low-pass filter as illustrated in FIG. 6A and a notch filter as illustrated in FIG. 6A and 6B, “resonance frequency” means the resonance frequency of the mold M and the mold holding unit 20. As illustrated in FIG. 6A, the low-pass filter can be set to have a cutoff frequency lower than the resonance frequency of the mold M and the mold holding unit 20. As illustrated in FIG. 6B, the notch filter can be set so that the removal band includes the resonance frequency of the mold M and the mold holding unit 20. The output limiter 183 includes the shift forces Fx ′ and Fy ′ as feedback resultant forces so that the shift forces Fx and Fy and the rotational force Frot as resultant forces are sufficiently smaller than the static friction force between the mold holding unit 20 and the mold M. And the rotational force Frot ′ is limited. The output limiter 183 can have input / output characteristics as illustrated in FIG.

  The distributor 190 has a plurality of shift forces Fx ′, Fy ′ and a rotational force Frot ′ as feedback resultant forces according to the equation (3) so as to distribute them to a plurality of forces to be generated by the plurality (m) of actuators 32. (M) force correction amounts cf1-cfm are generated.

・・・・（３）

.... (3)

(C _m3 ) is a matrix composed of m × 3 elements. The force target value f1-fm generated by the force target value generation unit 110 is corrected by the calculator 200 based on the force correction value cf1-cfm distributed by the distributor 190.

  FIG. 4 is a block diagram showing another configuration example of the adjusting device 30. In FIG. The adjustment device 30 shown in FIG. 4 has a loop for controlling the force applied to the mold M as a major loop and a loop for controlling the resultant force applied to the mold M as a minor loop. The configuration example shown is changed.

  In the adjusting device 30 (control unit 36) of the configuration example shown in FIG. 4, a plurality of force target values f1-fm are corrected based on a plurality of force measurement values af1-afm from a plurality of sensors 34. The one computing unit 203 is disposed between the force target value generation unit 110 and the plurality of compensators 120. In addition, a plurality of command values generated by the plurality of compensators 120 based on the outputs of the plurality of first computing units 203 are corrected based on a plurality of force correction amounts cf 1 -cfm output from the distributor 190. A second computing unit 204 is provided. The plurality of drivers 130 drive the plurality of actuators 32 based on the outputs of the plurality of second arithmetic units 204. In the configuration example shown in FIG. 4, the plurality of force correction amounts cf1 to cfm are reflected in the command values for the plurality of drivers 130 without passing through the plurality of compensators 120, so that the responsiveness for correcting the resultant force is improved. .

  As described above, according to the present embodiment, in the transient state before the deformation of the mold M is completed, the resultant force (Fx, Fy, Frot) applied to the mold M exceeds the allowable value, thereby causing the mold M to be misaligned. Rotation is prevented from occurring. Further, even in a steady state after the deformation of the mold M is completed, the mold M is displaced and / or rotated due to the force received by the mold M when the mold M contacts the imprint material on the substrate S. Is prevented.

  The control unit 36 is, for example, a PLD (abbreviation of Programmable Logic Device) such as FPGA (abbreviation of Field Programmable Gate Array), or an ASIC (abbreviation of Application Specific Integrated Circuit). It can be constituted by a computer or a combination of all or part of them. Alternatively, the plurality of components of the control unit 36 may be configured by individual circuits.

  A method for manufacturing a device (semiconductor integrated circuit element, liquid crystal display element, etc.) as an article includes a step of forming a pattern on a substrate (wafer, glass plate, film-like substrate) using the above-described imprint apparatus. Further, the manufacturing method may include a step of processing (for example, etching) the substrate on which the pattern is formed. In the case of manufacturing other articles such as patterned media (recording media) and optical elements, the manufacturing method may include other processes for processing a substrate on which a pattern is formed instead of etching. The article manufacturing method of this embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared with the conventional method.

DESCRIPTION OF SYMBOLS 1: Imprint apparatus, S: Board | substrate, M: Mold, 10: Board | substrate holding part, 20: Mold holding part, 30: Adjustment apparatus, 31: Support part, 32: Actuator, 34: Sensor, 36: Control part

Claims (10)

An adjustment device for adjusting the shape of the mold,
A plurality of actuators for applying a force to the mold to adjust the shape of the mold held by the mold holding unit;
A plurality of sensors for detecting a plurality of forces applied to the mold by the plurality of actuators;
A plurality of forces applied to the mold by the plurality of actuators based on outputs of the plurality of sensors, and a plurality of forces applied to the mold by the plurality of actuators so that the resultant force satisfies a restriction. A control unit for controlling
An adjustment device comprising: The controller is
A target value generating unit that generates a plurality of force target values that are target values of a plurality of forces generated by the plurality of actuators;
A resultant force calculator for calculating the resultant force based on the outputs of the plurality of sensors;
A feedback compensator for calculating a feedback resultant based on the resultant force;
A distributor for distributing the resultant feedback force to a plurality of forces to be generated by the plurality of actuators;
A plurality of computing units for correcting the plurality of force target values based on the outputs of the plurality of sensors and the outputs of the distributor;
A plurality of compensators that generate a plurality of command values based on outputs of the plurality of computing units, and
The adjustment device further includes a plurality of drivers that drive the plurality of actuators based on the plurality of command values.
The adjusting device according to claim 1. The controller is
A target value generating unit that generates a plurality of force target values that are target values of a plurality of forces generated by the plurality of actuators;
A resultant force calculator for calculating the resultant force based on the outputs of the plurality of sensors;
A feedback compensator for calculating a feedback resultant based on the resultant force;
A distributor for distributing the resultant feedback force to a plurality of forces to be generated by the plurality of actuators;
A plurality of first computing units for correcting the plurality of force target values based on outputs of the plurality of sensors;
A plurality of compensators for generating a plurality of command values based on outputs of the plurality of first computing units;
A plurality of second computing units that correct the plurality of command values based on the output of the distributor;
The adjustment device further includes a plurality of drivers that drive the plurality of actuators based on outputs of the plurality of second arithmetic units.
The adjusting device according to claim 1. The feedback compensator includes an output limiter that limits the output of the feedback compensator;
The adjusting device according to claim 2 or 3, wherein The feedback compensator includes a filter;
The adjustment device according to claim 2, wherein the adjustment device is a device. The filter includes at least one of a low pass filter and a notch filter,
The adjusting device according to claim 5, wherein: The resultant force is calculated with respect to a first axis and a second axis that are orthogonal to each other in a plane parallel to the surface of the mold, and a rotation about a third axis that is orthogonal to the first axis and the second axis. The
The adjustment device according to claim 1, wherein the adjustment device is a device. The limitation is determined such that the mold held by the mold holding unit does not cause displacement and / or rotation due to a force applied to the mold by the plurality of actuators.
The adjustment device according to claim 1, wherein the adjustment device is a device. An imprint apparatus for bringing a mold into contact with an imprint material supplied on a substrate and curing the imprint material,
A mold holding unit for holding the mold;
The adjustment device according to any one of claims 1 to 8, wherein the adjustment device is configured to adjust a shape of the mold held by the mold holding unit.
An imprint apparatus comprising: Forming a pattern on a substrate using the imprint apparatus according to claim 9;
Processing the substrate on which the pattern is formed;
An article manufacturing method comprising:

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