Control device, lithography device, manufacturing method and control method of article

Abstract

[Topic] This provides a technique that is advantageous for controlling the driving precision of a moving body. [Solution] A control device for controlling the driving of a moving body includes: an electromagnetic actuator that drives the moving body; a detection coil that outputs a voltage corresponding to the magnetic flux generated by the electromagnetic actuator; a correction unit that applies a correction value to the output of the detection coil and outputs a correction signal; a conversion unit that converts the correction signal into magnetic flux; and a control unit that controls the electromagnetic actuator based on the output of the conversion unit and a target magnetic flux; wherein the correction unit determines the correction value based on the signal obtained by the control unit and the output of the conversion unit, in a manner that reduces the drift component generated in the output of the conversion unit.

Description

Technical Field

[0001] The present invention relates to a control device, a lithography device, an article manufacturing method and a control method. Prior Art

[0002] In lithography equipment used in the manufacture of semiconductor devices and other applications, the substrate and platen mechanisms require high-speed and high-precision positioning of the stage (moving body). Actuators that drive the stage can employ linear motors that utilize the Lorentz force or electromagnetic actuators that utilize attractive forces. While linear motors offer excellent linearity and ease of handling, electromagnetic actuators have a high thrust constant, which is disadvantageous in terms of heat generation. Patent documents 1 and 2 propose methods for positioning the stage using both a linear motor and an electromagnetic actuator.

[0003] Electromagnetic actuators generally have a nonlinear relationship between the supplied current and the generated thrust, resulting in an error between the thrust generated by the electromagnetic actuator and the target thrust. To address this issue, Patent Document 1 proposes a method that detects the magnetic flux generated by the electromagnetic actuator through a search coil and, based on the detection results, performs feedback control to ensure that the thrust generated by the electromagnetic actuator reaches the target thrust.

[0004] Furthermore, the integrator used to detect the magnetic flux of the electromagnetic actuator can drift due to external disturbances. Patent Document 2 proposes a method for correcting this drift. Specifically, when the flux command indicates zero (i.e., when the electromagnetic actuator is not generating flux), the integrator's output value is used to correct the integrator's input value without actuating the hold switch. On the other hand, when the flux command does not indicate zero (i.e., when the electromagnetic actuator is generating flux), the hold switch is actuated to hold the previous value, and drift correction is performed using this previous value as the external disturbance component. [Prior Art Literature] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-218188 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-89598 Summary of the Invention

[0006] [Problems to be solved by the invention]

[0007] When using a linear motor and an electromagnetic actuator together, the electromagnetic actuator primarily controls the acceleration and deceleration of the stage during acceleration and deceleration periods requiring high thrust, while the linear motor performs minute positioning of the stage during constant speed periods where high thrust is not required. This enables high-speed and high-precision stage positioning control. However, the combination of a linear motor and an electromagnetic actuator results in a redundant number of actuators being deployed in the direction of the stage's drive, which is disadvantageous in terms of device cost. Therefore, a method is being developed that eliminates the use of the linear motor, which has a lower thrust constant than the other two types of electromagnetic actuators, and instead uses only the electromagnetic actuator for stage positioning control, thereby reducing device cost.

[0008] When the stage positioning is controlled solely by an electromagnetic actuator, the electromagnetic actuator must constantly output magnetic flux (thrust). In this case, there are no periods where the magnetic flux command is zero (i.e., periods when the electromagnetic actuator does not generate magnetic flux). Therefore, the method described in Patent Document 2 cannot adequately correct the integrator's drift, making it difficult to accurately control the stage's drive.

[0009] Therefore, an object of the present invention is to provide a technique that is advantageous in controlling the driving of a moving body with high precision. [Means for solving the problem]

[0010] In order to achieve the above-mentioned purpose, a control device as one aspect of the present invention is a control device that controls the drive of a moving body and comprises: an electromagnetic actuator that drives the above-mentioned moving body; a detection coil that outputs a voltage corresponding to the magnetic flux generated by the above-mentioned electromagnetic actuator; a correction unit that applies a correction value to the output of the above-mentioned detection coil and outputs a correction signal; a conversion unit that converts the above-mentioned correction signal into magnetic flux; and a control unit that controls the above-mentioned electromagnetic actuator based on the output of the above-mentioned conversion unit and the target magnetic flux; the above-mentioned correction unit determines the above-mentioned correction value based on the signal obtained by the above-mentioned control unit and the output of the above-mentioned conversion unit in a manner such that the drift component generated in the output of the above-mentioned conversion unit is reduced.

[0011] Further objects and other aspects of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. [Effects of the invention]

[0012] According to the present invention, for example, a technique that is advantageous in controlling the driving of a moving body with high precision can be provided. Simple diagram description

[0013] [Figure 1] A schematic diagram illustrating an example of the configuration of a stage device. [Figure 2] A block diagram illustrating a conventional electromagnet control system. FIG3 is a block diagram illustrating the electromagnet control system according to the first embodiment. FIG4 is a block diagram illustrating an electromagnet control system according to a second embodiment. [Figure 5] A schematic diagram illustrating an example of the structure of a lithography apparatus. Implementation Method

[0014] The following describes the embodiments in detail with reference to the drawings. The following embodiments do not limit the scope of the claimed invention. While multiple features are described in the embodiments, not all of these features are essential to the invention; furthermore, multiple features may be combined in any desired manner. In the drawings, identical or similar components are denoted by the same reference numerals, and repeated descriptions are omitted.

[0015] In the following embodiments, a stage device (positioning device) that controls the drive of a movable body, such as a control device for controlling the drive of a movable body, is described. Specifically, the movable body driven by the control device includes at least one of a platen stage for holding a platen and a substrate stage for holding a substrate. Furthermore, the movable body is not limited to a stage; any object driven by an electromagnetic actuator may be used.

[0016] The conventional stage device described in Patent Document 2 is configured so that the electromagnetic actuator outputs magnetic flux (thrust) only during the stage's acceleration and deceleration periods. However, with this configuration, it is impossible to adequately correct drift in the detected magnetic flux caused by external disturbances while the electromagnetic actuator is outputting magnetic flux. For example, when the electromagnetic actuator outputs magnetic flux for a short period of time, such as during the stage's acceleration and deceleration periods, the effect of drift in the detected magnetic flux caused by external disturbances is minimal. Therefore, even if drift correction is disabled, the electromagnetic actuator can still accurately control the magnetic flux. On the other hand, when the electromagnetic actuator outputs magnetic flux during the stage's constant speed period, the constant speed period is longer than during the acceleration and deceleration periods, so the duration of the magnetic flux output also increases. Consequently, the electromagnetic actuator is significantly affected by drift in the detected magnetic flux caused by external disturbances, making it difficult to accurately control the magnetic flux of the electromagnetic actuator. Accordingly, the conventional stage device described in Patent Document 2 uses a linear motor for positioning control in the constant speed range, and the drift of the detected magnetic flux is corrected during position control by the linear motor. In contrast, the following embodiment provides, by way of example, an electromagnetic actuator control system that simultaneously achieves both the output of the electromagnetic actuator and the correction of drift of the detected magnetic flux caused by external disturbances, regardless of whether the stage is in the acceleration / deceleration range or the constant speed range. The configuration of the electromagnetic actuator control system described in the following embodiment allows the electromagnetic actuator's magnetic flux to be accurately controlled even in the constant speed range of the stage. Consequently, the stage device in the following embodiment can eliminate the linear motor used for stage positioning, allowing stage positioning control to be performed solely by the electromagnetic actuator.

[0017] <First embodiment> The first embodiment of the present invention will be described. Figure 1 is a schematic diagram illustrating an example configuration of a stage device 100 according to this embodiment, viewed from above (in the Z direction). The stage device 100 according to this embodiment can be composed of a coarse movement stage 101, which has a large stroke and high thrust despite poor positioning accuracy, a fine movement stage 102, which has a small stroke but high positioning accuracy, and a drive control unit 110. The drive control unit 110, for example, is comprised of a computer including a processing unit such as a central processing unit (CPU) and a storage unit such as a memory. It controls various actuators and thereby controls the drive of the coarse movement stage 101 and the fine movement stage 102. Furthermore, in this embodiment, the fine movement stage 102 can be configured to hold an object such as a master plate or substrate through vacuum suction, electrostatic suction, or the like.

[0018] Coarse movement stage 101 is driven in a predetermined direction (±Y directions in Figure 1) by coarse movement linear motors 103 (103a, 103b). Furthermore, fine movement stage 102 is non-contactably connected to coarse movement stage 101 and driven in a predetermined direction (±Y directions in Figure 1) relative to coarse movement stage 101 by electromagnetic actuators 104 (104a, 104b).

[0019] Generally speaking, while linear motors have excellent linearity in terms of thrust generated by supplied current and are easy to handle, they also have a small thrust constant and generate a large amount of heat per unit current. On the other hand, electromagnetic actuators (electromagnets) have poor linearity, but they have a large thrust constant and generate a small amount of heat per unit current. Therefore, in this embodiment, the fine motion stage 102 is driven not by a linear motor, but by electromagnetic actuators 104 (104a, 104b). That is, in this embodiment, the stage device 100 performs positioning control and acceleration / deceleration control of the fine motion stage 102 solely using the electromagnetic actuators 104. The electromagnetic actuators 104 are constructed to include an electromagnet that generates magnetic flux by supplying current to a coil. This attractive force acts on a magnetic plate that forms part of the fine motion stage 102.

[0020] [Conventional electromagnetic actuator control systems] The following describes a conventional electromagnetic actuator control system with reference to Figure 2. Figure 2 is a block diagram illustrating the control system (electromagnetic control system) of the conventional electromagnetic actuator 104 described in Patent Document 2. Figure 2 shows the electromagnet control system for either of the two electromagnetic actuators 104a and 104b in Figure 1. The force generated by the electromagnetic actuator 104 is proportional to the square of the magnetic flux between the electromagnet and the magnetic plate. In the electromagnet control system, command information (hereinafter sometimes referred to as "flux command") having a dimension equal to the square root of the absolute value of the acceleration / deceleration force is supplied from the main control unit (e.g., the drive control unit 110) responsible for sequence control of the entire stage.

[0021] The electromagnetic actuator 104 may include an electromagnetic yoke 301 and a drive coil 302 provided on the electromagnetic yoke 301. Furthermore, a detection coil 303 is provided on the electromagnetic yoke 301 of the electromagnetic actuator 104. The detection coil 303 detects the magnetic flux generated by the drive coil 302 and outputs an induced voltage v corresponding to the magnetic flux. This induced voltage v is supplied to the first calculation unit 308. The first calculation unit 308 applies a correction value to the output of the detection coil 303 (induced voltage v) and outputs the resulting signal as a correction signal. The correction value for the induced voltage v can be applied, for example, by adding the correction value to the induced voltage v or subtracting the correction value from the induced voltage v.

[0022] The conversion unit 304 converts the correction signal output from the first calculation unit 308 into magnetic flux. For example, the conversion unit 304 includes an integrator that time-integrates the correction signal output from the first calculation unit 308 to output magnetic flux. The magnetic flux output from the conversion unit 304 can be understood as the detection result of the magnetic flux generated by the electromagnetic actuator 104 and may be referred to below as "detected magnetic flux φd." The magnetic flux required to cause the electromagnetic actuator 104 to generate the desired force can be calculated based on the number of turns of the detection coil 303, the cross-sectional area of ​​the portion of the electromagnetic yoke 301 where the detection coil 303 is provided, and the detected magnetic flux φd output from the conversion unit 304. Furthermore, in the conventional electromagnet control system shown in FIG. 2 , a reset signal S1 is supplied to the conversion unit 304 for setting the detected magnetic flux to zero upon device startup. When the reset signal S1 is input to the conversion unit 304, the output of the conversion unit 304 becomes zero.

[0023] The detected magnetic flux φd output from the conversion unit 304 is supplied to the second calculation unit 305 (subtractor, adder). The second calculation unit 305 calculates a magnetic flux error, which is the difference between the input magnetic flux command (target magnetic flux) and the detected magnetic flux φd, and supplies this magnetic flux error to the gain unit 306. The gain unit 306 (generator) generates a voltage command value based on the magnetic flux error output from the second calculation unit 305. For example, the gain unit 306 multiplies the magnetic flux error output from the second calculation unit 305 by an appropriate (predetermined) gain to generate a voltage command value, which is then supplied to the drive amplifier 307. The drive amplifier 307 (supply unit) supplies a current i to the electromagnetic actuator 104 (the electromagnet's drive coil 302) based on the voltage command value output from the gain unit 306. Specifically, the driver amplifier 307 applies a voltage corresponding to the voltage command value supplied from the gain unit 306 to the drive coil 302, thereby supplying a current to the drive coil 302 of the electromagnetic actuator 104 to generate a magnetic flux corresponding to the magnetic flux command (target magnetic flux). This generates the desired magnetic flux (i.e., the target magnetic flux) in the electromagnetic actuator 104.

[0024] However, in the electromagnet control system configured as described above, even when the flux command indicates zero, an offset current may still flow through the drive coil 302 and / or the detection coil 303 due to the influence of external disturbances. This offset current is time-integrated in the converter 304 and is included as an unnecessary drift component in the detection flux φd output from the converter 304. In other words, a drift component due to external disturbances is generated in the detection flux φd output from the converter 304. In this case, the electromagnetic actuator 104 cannot be controlled to generate a magnetic flux corresponding to the flux command (target flux), making it difficult to accurately position the fine-motion stage 102, the movable body. For this reason, conventional electromagnet control systems have included a drift correction system 401 for correcting the drift component of the detection flux φd output from the converter 304. 2 , the external disturbance that causes the drift component in the detection magnetic flux φ d output from the conversion unit 304 is equivalently represented as “external disturbance A” and is schematically illustrated as being input to the first calculation unit 308 .

[0025] The conventional electromagnet control system shown in FIG2 (Patent Document 2) utilizes the ideal state that, when the magnetic flux command indicates zero, the current i flowing through the drive coil 302 is zero, and the detected magnetic flux φd is also zero, to reduce the drift component of the detected magnetic flux φd. Specifically, when the magnetic flux command indicates zero, if the detected magnetic flux φd output from the converter 304 is non-zero, this detected magnetic flux φd is assumed to be a drift component caused by external disturbances, and drift correction is performed to correct the input value of the converter 304 using this detected magnetic flux φd. On the other hand, when the magnetic flux command does not indicate zero, that is, when the electromagnetic actuator 104 is generating magnetic flux, the hold switch 401b is actuated to hold the previous value, and drift correction is performed using this previous value.

[0026] Specifically, in the conventional drift correction system 401 shown in Figure 2, when the magnetic flux command indicates zero, the hold switch 401b is turned off (inactive). In this case, the detected magnetic flux φd output from the conversion unit 304 is multiplied by the gain g2 in the conversion unit 401a to obtain a voltage value converted from the detected magnetic flux φd. This voltage value is fed back to the first calculation unit 308 as a correction value. The first calculation unit 308 subtracts the correction value from the induced voltage v output from the detection coil 303 and inputs the resulting signal to the conversion unit 304. On the other hand, when the magnetic flux command does not indicate zero, the drive timing command S2 is provided to the hold switch 401b, turning it on (active). In this case, the feedback loop of the drift correction system 401 is substantially cut off, and the previous voltage value converted from the detected magnetic flux φ d is retained. The retained voltage value is sequentially input to the first calculation unit 308 as a correction value. Next, we examine the transfer characteristics from the current i flowing through the drive coil 302 to the detected magnetic flux φd when the switch 401b is held off. Let the current flowing through the drive coil 302 be i and the magnetic flux generated by the drive coil 302 be φ. The relationship between the current i and the magnetic flux φ is expressed using the coefficient G as shown in Equation (1).

[0027] φ: Output magnetic flux of the driving coil G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. i: Current driving the coil

[0028] The transfer characteristic T φ v(s) from the magnetic flux φ generated in the driving coil 302 to the induced voltage v is expressed as shown in Formula (2) using the coefficient N.

[0029] T φ v(s): Transfer characteristic from magnetic flux to induced voltage N: coefficient determined by the number of turns of the detection coil, etc.

[0030] In addition, the transfer characteristic T v φ d (s) from the induced voltage v to the detection magnetic flux φ d is expressed as in equation (3).

[0031] T v φ d(s): Transfer characteristic from induced voltage v to detected magnetic flux φ d g1: Gain of the conversion unit 304 (integrator)

[0032] Based on this, when the switch 401b is turned off, the transfer characteristic T i φ d(s) from the current i of the drive coil 302 to the detected magnetic flux φ d is expressed as equation (4) using equations (1) to (3). The current i of the drive coil 302 and the magnetic flux φ generated by the drive coil 302 are in a constant multiple relationship. Therefore, when the transfer characteristic from the current i of the drive coil 302 to the detected magnetic flux φ d is expressed as a constant multiple as in equation (4), the detected magnetic flux φ d can be obtained with good accuracy. In other words, when the magnetic flux command indicates zero, that is, when the switch 401b is turned off, the feedback loop of the drift correction system 401 can accurately control the electromagnetic actuator 104 based on the detected magnetic flux φ d.

[0033] T i φ d(s): Transfer characteristic from the current i of the driving coil to the detection magnetic flux φ d G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. N: coefficient determined by the number of turns of the detection coil, etc. g1: Gain of the conversion unit 304 (integrator)

[0034] Here, we examine the case where the drive of the micro-motion stage 102 is controlled using only the electromagnetic actuator 104. In this case, the electromagnetic actuator 104 must be kept in a state where it is always driven (i.e., where magnetic flux is generated). In the conventional configuration shown in FIG2 (Patent Document 2), when the electromagnetic actuator 104 is always driven, the timing at which the magnetic flux instruction indicates zero disappears, and the switch 401b is kept turned on (activated) at all times. Therefore, when the magnetic flux instruction indicates zero, it is impossible to achieve the ideal state where the detected magnetic flux φ d is zero. On the other hand, in order to correct the drift component of the detected magnetic flux φ d caused by the external disturbance A, when the switch 401b is kept turned on (activated) at all times while maintaining the conventional configuration, the transfer characteristic T v φ d (s) from the induced voltage v to the detected magnetic flux φ d is expressed as shown in Equation (5). In other words, it becomes a first-order lag filter characteristic.

[0035] T v φ d(s): Transfer characteristic from induced voltage v to detected magnetic flux φ d g1: Gain of the conversion unit 304 (integrator) g2: Gain of the conversion unit 401a

[0036] Based on this, the transfer characteristic T i φ d(s) from the current i of the drive coil 302 to the detection magnetic flux φ d can be expressed as in equation (6) using equations (1) to (2) and (5). This is inconsistent with the transfer characteristic from the current i to the detection magnetic flux φ d when the holding switch 401b is off. In other words, when the magnetic flux command does not indicate zero, that is, when the holding switch 401b is on, the detection magnetic flux φ d cannot be accurately obtained, and it becomes difficult to accurately control the electromagnetic actuator 104 based on the detection magnetic flux φ d. In other words, the structure of the conventional electromagnet control system is not suitable for controlling the drive of the fine motion stage 102 using only the electromagnetic actuator 104.

[0037] T i φ d(s): Transfer characteristic from the current i of the driving coil to the detection magnetic flux φ d G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. N: coefficient determined by the number of turns of the detection coil, etc. g1: Gain of the conversion unit 304 (integrator) g2: Gain of the conversion unit 401a

[0038] [Control System of Electromagnetic Actuator in This Embodiment] The following describes the control system of the electromagnetic actuator in this embodiment with reference to FIG3 . FIG3 is a block diagram illustrating the control system (electromagnetic control system) of the electromagnetic actuator 104 in this embodiment. Similar to FIG2 , FIG3 illustrates the electromagnetic control system for either of the two electromagnetic actuators 104a and 104b in FIG1 .

[0039] The electromagnet control system of this embodiment shown in FIG3 differs from the conventional electromagnet control system shown in FIG2 in terms of the structure of the drift correction system, but otherwise is essentially the same. For example, the electromagnetic actuator 104 can be configured as described above with reference to FIG2 , including an electromagnet yoke 301 and a drive coil 302 provided on the electromagnet yoke 301. Furthermore, a detection coil 303 is provided on the electromagnet yoke 301 of the electromagnetic actuator 104. The detection coil 303 detects the magnetic flux generated by the drive coil 302 and outputs a voltage (induced voltage v) that is the differential value of this magnetic flux. The induced voltage v output from the detection coil 303 is supplied to a first calculation unit 308. The first calculation unit 308 is configured as a correction unit that applies a correction value to the output of the detection coil 303 (induced voltage v), and outputs a signal obtained by applying the correction value to the induced voltage v as a correction signal. The correction value for the induced voltage v can be applied, for example, by adding the correction value to the induced voltage v or subtracting the correction value from the induced voltage v. Furthermore, the correction value applied to the induced voltage v in the first calculation unit 308 can also be understood as a value for reducing (correcting) the drift component generated in the output (detected magnetic flux φ d) of the conversion unit 304 .

[0040] The conversion unit 304 converts the correction signal output from the first calculation unit 308 into magnetic flux and outputs it as the detected magnetic flux φd. In this embodiment, the conversion unit 304 includes an integrator that integrates the correction signal output from the first calculation unit 308 over time to output the detected magnetic flux φd. This integrator can be implemented using an analog circuit. Alternatively, the conversion unit 304 can include a filter with integrating characteristics instead of an integrator, which can be used to integrate the correction signal over time to output the detected magnetic flux φd.

[0041] The detected magnetic flux φd output from the conversion unit 304 is supplied to the second calculation unit 305 (subtractor, adder). The second calculation unit 305 calculates a magnetic flux error, which is the difference between the input magnetic flux command (target magnetic flux) and the detected magnetic flux φd, and supplies this magnetic flux error to the gain unit 306. The gain unit 306 (generator) generates a voltage command value based on the magnetic flux error output from the second calculation unit 305. For example, the gain unit 306 multiplies the magnetic flux error output from the second calculation unit 305 by an appropriate (predetermined) gain to generate a voltage command value, which is then supplied to the drive amplifier 307. The drive amplifier 307 (supply unit) supplies a current i to the electromagnetic actuator 104 (the electromagnet's drive coil 302) based on the voltage command value output from the gain unit 306. This allows the desired magnetic flux (i.e., the target magnetic flux) to be generated in the electromagnetic actuator 104. In this embodiment, the second calculation unit 305, the gain unit 306 (generator), and the drive amplifier 307 (supply unit) constitute a control unit CNT that controls the electromagnetic actuator 104 based on the output of the conversion unit 304 (detected magnetic flux φd) and the target magnetic flux (flux command). Furthermore, the conversion unit 304, the second calculation unit 305, the gain unit 306, the drive amplifier 307, the first calculation unit 308, and the drift correction system 501 described below may be components of the drive control unit 110 described in FIG. 1 .

[0042] Next, an example configuration of the drift correction system 501 of this embodiment will be described. As shown in FIG3 , the drift correction system 501 of this embodiment may include a first conversion unit 501a, a second conversion unit 501b, and a difference calculation unit 501c. Furthermore, the drift correction system 501 of this embodiment determines the correction value to be supplied to the first calculation unit 308 (correction unit) based on the signal obtained by the control unit CNT and the output of the conversion unit 304 (detected magnetic flux φd) so as to reduce the drift component generated in the output of the conversion unit 304. While the current i output from the driver amplifier 307 is used as the signal obtained by the control unit CNT, this is not limiting; the magnetic flux error (deviation) output from the second calculation unit 305 or the voltage command value output from the gain unit 306 may also be used.

[0043] The first conversion unit 501a is set with a gain g3 (first gain) for converting the signal (current i) obtained by the control unit CNT into a magnetic flux. The first conversion unit 501a multiplies the current i output from the driver amplifier 307 by the gain g3 to convert the current i into a magnetic flux, and outputs the magnetic flux information obtained in this manner as the current feedback signal S3. The difference calculation unit 501c calculates the difference (hereinafter sometimes referred to as "magnetic flux difference") between the magnetic flux converted from the current i by the first conversion unit 501a and the detected magnetic flux φd output from the conversion unit 304. Furthermore, the second conversion unit 501b is set with a gain g2 (second gain) for converting the magnetic flux difference calculated by the difference calculation unit 501c into a voltage value. The second conversion unit 501b converts the magnetic flux difference calculated by the difference calculation unit 501c into a voltage value by multiplying the gain g2. The voltage value obtained in this manner is supplied as a correction value to the first calculation unit 308. The gain g3 of the first conversion unit 501a and the gain g2 of the second conversion unit 501b can be determined in advance through, for example, experiments, simulations, etc.

[0044] As mentioned above, the current i of the drive coil 302 and the magnetic flux generated by the drive coil 302 are in a constant-multiplier relationship. In the drift correction system 501 of this embodiment, this relationship is utilized to generate magnetic flux information obtained by multiplying the current i of the drive coil 302 by the gain g3 as a current feedback signal S3. This generated current feedback signal S3 is input to the difference calculation unit 501c. At this time, the transfer characteristic T i φ d(s) from the current i of the drive coil 302 to the detected magnetic flux φ d is expressed as Equation (7).

[0045] T i φ d(s): Transfer characteristic from the current i of the driving coil to the detection magnetic flux φ d G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. N: coefficient determined by the number of turns of the detection coil, etc. g1: Gain of the conversion unit 304 (integrator) g2: Gain of the second conversion unit 501b g3: Gain of the first conversion unit 501a

[0046] The gain g3 (current gain) of the first conversion unit 501a is appropriately set so that the magnetic flux generated by the electromagnetic actuator 104 can be calculated (estimated, predicted) based on the current i supplied from the drive amplifier 307 to the drive coil 302. In other words, the current feedback signal S3 (magnetic flux information) can be calculated (reproduced) as a signal (information) representing the magnetic flux corresponding to the induced voltage v output from the detection coil 303 within the detection magnetic flux φd output from the conversion unit 304. Consequently, the difference calculation unit 501c can output (extract) the drift component of the detection magnetic flux φd caused by the external disturbance A as a magnetic flux difference, and can only feedback this drift component. The gain g3 of the first conversion unit 501a is determined by equation (8).

[0047] g3: Gain of the first conversion unit 501a G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. N: coefficient determined by the number of turns of the detection coil, etc. g1: Gain of the conversion unit 304 (integrator)

[0048] At this time, the transfer characteristic T i φ d(s) from the current i of the drive coil 302 to the detection magnetic flux φ d is expressed as Equation (9) by substituting Equation (8) into Equation (7). The transfer characteristic T i φ d(s) expressed in Equation (9) is consistent with the transfer characteristic T i φ d(s) from the current i to the detection magnetic flux φ d when the holding switch 401b is off, expressed in Equation (4). In other words, the detection magnetic flux φ d can be obtained with high accuracy. Therefore, the electromagnetic actuator 104 can be controlled with high accuracy based on the detection magnetic flux φ d.

[0049] T i φ d(s): Transfer characteristic from the current i of the driving coil to the detection magnetic flux φ d G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. N: coefficient determined by the number of turns of the detection coil, etc. g1: Gain of the conversion unit 304 (integrator) g2: Gain of the second conversion unit 501b

[0050] Furthermore, the transfer characteristic TA φ d(s) from the external disturbance A to the detected magnetic flux φ d is expressed as shown in Equation (10). In other words, it can be seen that applying a first-order lag filter characteristic to the external disturbance A reduces the drift component of the detected magnetic flux φ d. Based on this, it can be seen that in the electromagnet control system using the drift correction system 501 of this embodiment, the output of the electromagnetic actuator 104 can be controlled while the drift component of the detected magnetic flux φ d caused by the external disturbance A can be corrected simultaneously. In other words, the drive accuracy of the fine-motion stage 102 can be controlled with good accuracy using only the electromagnetic actuator 104.

[0051] TA φ d(s): Transfer characteristics from external disturbance A to detection magnetic flux φ d g1: Gain of the conversion unit 304 (integrator) g2: Gain of the second conversion unit 501b

[0052] As described above, the electromagnet control system of this embodiment determines the correction value to be supplied to the first calculation unit 308 based on the signal obtained by the control unit CNT and the output of the conversion unit 304 (detected magnetic flux φd) so as to reduce the drift component generated in the output of the conversion unit 304. Consequently, even when the electromagnetic actuator 104 is constantly driven, the drift component of the detection magnetic flux φd output from the conversion unit 304 can be extracted and reduced with high precision. In other words, the drive of the fine motion stage 102 can be controlled with high precision using only the electromagnetic actuator 104.

[0053] <Second embodiment> The second embodiment of the present invention will now be described. Figure 4 is a block diagram illustrating the control system (electromagnet control system) for the electromagnetic actuator 104 in this embodiment. While the first embodiment described an example in which the converter 304 includes an integrator, this embodiment will describe an example in which the converter 304 includes a digital filter 601. The digital filter 601 of the converter 304 performs a discrete-time integration of the induced voltage v output from the detection coil 303 to output the detected magnetic flux φd. This digital filter 601 can be implemented using a digital circuit such as an FIR (Finite Impulse Response) filter, an IIR (Infinite Impulse Response) filter, or an adder. Furthermore, the value output from the digital filter 601 may be an integrated value within a specific interval. This embodiment essentially follows the first embodiment and, with the exception of the following matters, can be adapted to the first embodiment.

[0054] First, we examine the transfer characteristics from current i in drive coil 302 to detected magnetic flux φd when the feedback loop of drift correction system 501 is essentially split. When the current in drive coil 302 is i and the magnetic flux generated by drive coil 302 is φ, the relationship between current i and magnetic flux φ is expressed using the coefficient G as shown in Equation (11).

[0055] φ: Output magnetic flux of the driving coil G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. i: Current driving the coil

[0056] Furthermore, the discrete transfer characteristic T φ v(z) from the magnetic flux φ generated in the driving coil 302 to the induced voltage v is expressed as in equation (12) using the coefficient N.

[0057] T φ v(z): Transfer characteristic from magnetic flux φ to induced voltage v N: coefficient determined by the number of turns of the detection coil, etc.

[0058] In addition, the discrete transfer characteristic F(z) of the digital filter 601 performing discrete-time integration is expressed as equation (13).

[0059] F(z): Discrete transfer characteristic of digital filter 601 g 4: Gain of digital filter 601

[0060] Based on this, the transfer characteristic T i φ d(z) from the current i of the driving coil 302 to the detected magnetic flux φ d can be expressed as Equation (14) using Equations (11) to (13). The current i of the driving coil 302 and the magnetic flux generated by the driving coil 302 are in a constant-multiplied relationship. Therefore, when the transfer characteristic from the current i of the driving coil 302 to the detected magnetic flux φ d is expressed as a constant-multiplied relationship as in Equation (14), the detected magnetic flux φ d can be obtained with good accuracy.

[0061] T i φ d(z): Transfer characteristic from the current i of the driving coil to the detection magnetic flux φ d G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. N: coefficient determined by the number of turns of the detection coil, etc. g 4: Gain of digital filter 601

[0062] Here, taking advantage of the fact that the current i of the driving coil 302 and the magnetic flux φ generated by the driving coil 302 are constant multiples, the magnetic flux information obtained by multiplying the current i of the driving coil 302 by the gain g3 of the first conversion unit 501a is generated as the current feedback signal S3. This generated current feedback signal S3 is then input to the difference calculation unit 501c. At this point, the transfer characteristic T i φ d(z) from the current i of the driving coil 302 to the detected magnetic flux φ d is expressed as Equation (15).

[0063] T i φ d(z): Transfer characteristic from the current i of the driving coil to the detection magnetic flux φ d G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. N: coefficient determined by the number of turns of the detection coil, etc. g2: Gain of the second conversion unit 501b g3: Gain of the first conversion unit 501a g 4: Gain of digital filter 601

[0064] The gain g3 (current gain) of the first conversion unit 501a is appropriately set so that the magnetic flux generated by the electromagnetic actuator 104 can be calculated (estimated, predicted) based on the current i supplied from the drive amplifier 307 to the drive coil 302. In other words, the current feedback signal S3 (magnetic flux information) can be calculated (reproduced) as a signal (information) representing the magnetic flux corresponding to the induced voltage v output from the detection coil 303 within the detection magnetic flux φd output from the conversion unit 304 (digital filter 601). Consequently, the difference calculation unit 501c can output (extract) the drift component of the detection magnetic flux φd caused by the external disturbance A as a magnetic flux difference, and can only feedback this drift component. The gain g3 of the first conversion unit 501a is determined by equation (16).

[0065] g3: Gain of the first conversion unit 501a G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. N: coefficient determined by the number of turns of the detection coil, etc. g 4: Gain of digital filter 601

[0066] At this time, the transfer characteristic T i φ d(z) from the current i of the drive coil to the detection magnetic flux φ d is expressed as Equation (17) by substituting Equation (16) into Equation (15). The transfer characteristic T i φ d(z) expressed in Equation (17) is consistent with the transfer characteristic from the current i of the drive coil 302 to the detection magnetic flux φ d expressed in Equation (14). In other words, the detection magnetic flux φ d can be obtained with high accuracy. Therefore, the electromagnetic actuator 104 can be controlled with high accuracy based on the detection magnetic flux φ d.

[0067] T i φ d(z): Transfer characteristic from the current i of the driving coil to the detection magnetic flux φ d G: A coefficient determined by the number of turns of the drive coil, the magnetic permeability of the magnetic material, etc. N: coefficient determined by the number of turns of the detection coil, etc. g2: Gain of the second conversion unit 501b g 4: Gain of digital filter 601

[0068] Furthermore, the transfer characteristic TA φ d(z) from the external disturbance A to the detected magnetic flux φ d is expressed as in Equation (18). In other words, it can be seen that by applying a discrete first-order lag filter characteristic to the external disturbance A, the drift component of the detected magnetic flux φ d is reduced. Based on this, it can be seen that even when the integrator in the conversion unit 304 is replaced with the digital filter 601, similar to the first embodiment, the output of the electromagnetic actuator 104 can be controlled while the drift component of the detected magnetic flux φ d caused by the external disturbance A is corrected simultaneously. In other words, the drive accuracy of the fine-motion stage 102 can be controlled with good accuracy using only the electromagnetic actuator 104.

[0069] TA φ d(z): Transfer characteristic from external disturbance A to detection magnetic flux φ d g2: Gain of the second conversion unit 501b g 4: Gain of digital filter 601

[0070] The advantage of this embodiment lies in the ease with which the gain parameters of digital filter 601 can be modified. For example, if the transfer characteristics from external disturbance A to detected magnetic flux φd were to be modified based on the characteristics of external disturbance A, implementing this with an analog circuit would require changing the components implemented in the circuit. However, with this embodiment, the desired transfer characteristics can be achieved simply by changing the parameters of digital filter 601.

[0071] <Implementation Method of Lithography Apparatus> An example of using the stage device (control device) described in the first or second embodiment in a lithography apparatus for forming a pattern on a substrate will be described. Examples of lithography apparatuses include exposure apparatuses that expose a substrate to transfer a pattern on a master plate (mask) to the substrate, and imprint apparatuses that use a master plate (mold) to form a pattern on an imprint material on a substrate. In such lithography apparatuses, the stage device can be used to control the movement of a stage that moves while holding at least one of the master plate (mask, mold) and the substrate. The following describes an example of using the stage device in an exposure apparatus.

[0072] FIG5 is a schematic diagram illustrating an example configuration of an exposure apparatus 10 employing the stage device of the present invention. The exposure apparatus 10 may include an illumination system 11, a reticle stage 13 capable of moving while holding a reticle 12, a projection system 14, and a substrate stage 16 capable of moving while holding a substrate 15. The stage device of the first or second embodiment described above may be applied to at least one of the reticle stage 13 and the substrate stage 16.

[0073] <Methods for manufacturing articles> The method for manufacturing an article according to an embodiment of the present invention is suitable for manufacturing, for example, microdevices such as semiconductor devices, and articles having fine structures, such as components. The method for manufacturing an article according to this embodiment includes: a formation process for forming a pattern on a substrate using the aforementioned lithography apparatus; a processing process for processing the substrate patterned in the formation process; and a process for manufacturing an article from the substrate processed in the processing process. Furthermore, the method for manufacturing an article according to this embodiment includes other well-known processes (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). Compared to conventional methods, the method for manufacturing an article according to this embodiment offers advantages in at least one of the following: article performance, quality, productivity, and production cost.

[0074] <Other embodiments> The present invention may also be implemented by supplying a program that implements one or more functions of the above-described embodiments to a system or device via a network or storage medium, and having one or more processors in a computer of the system or device read and execute the program. Furthermore, implementation may be achieved using a circuit (e.g., an ASIC) that implements one or more functions.

[0075] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention is disclosed by drafting the patent application.

[0076] 100: stage device (control device) 102: Micro-motion stage 104: Electromagnetic actuator 302: driving coil 303: Detection coil 304:Conversion Department 305: Second Calculation Department 306: Gain unit (generation unit) 307: Driver amplifier (supply department) 308: First calculation unit (correction unit) 501:Drift correction system 501a: First conversion unit 501b: Second conversion unit 501c: Difference calculation unit

Claims

1. A control device for controlling the driving of a moving body, comprising: an electromagnetic actuator that drives the moving body; a detection coil that outputs a voltage value corresponding to a magnetic flux generated by the electromagnetic actuator; a correction unit that applies a correction value to the output of the detection coil and outputs a correction signal; a conversion unit that converts the correction signal into a magnetic flux; and a control unit that controls the electromagnetic actuator based on the output of the conversion unit and a target magnetic flux; wherein the correction unit determines the correction value based on the signal obtained by the control unit and the output of the conversion unit, in a manner that reduces the drift component generated in the output of the conversion unit.

2. The control device as requested in item 1, wherein, The aforementioned correction unit determines the aforementioned correction value based on the difference between the magnetic flux converted from the aforementioned signal obtained by the aforementioned control unit and the magnetic flux output from the aforementioned conversion unit.

3. The control device as requested in claim 2, wherein, The aforementioned correction unit is provided with a first gain for converting the aforementioned signal obtained by the aforementioned control unit into a magnetically universal first gain.

4. The control device as claimed in claim 2, wherein, The aforementioned correction unit applies the voltage value converted from the aforementioned differential as the aforementioned correction value to the output of the aforementioned detection coil.

5. The control device as claimed in claim 4, wherein, The aforementioned correction unit is provided with a second gain for converting the aforementioned differential into a voltage value.

6. The control device as requested in claim 1, wherein, The aforementioned conversion unit performs time integration on the aforementioned correction signal to convert the aforementioned correction signal into magnetic flux.

7. The control device as claimed in claim 6, wherein, The aforementioned conversion unit includes an integrator that integrates the aforementioned correction signal over time.

8. The control device as claimed in claim 6, wherein, The aforementioned conversion unit includes a filter that performs time integration on the aforementioned correction signal.

9. The control device as claimed in claim 1, wherein, The signal obtained from the aforementioned control unit is a voltage or current, which is generated based on the output of the aforementioned conversion unit and the aforementioned target magnetic flux in order to control the aforementioned electromagnetic actuator.

10. The control device as claimed in claim 1, wherein, The aforementioned control unit includes: a calculation unit that calculates the deviation between the output of the aforementioned conversion unit and the aforementioned target magnetic flux; a generation unit that generates a voltage command value based on the aforementioned deviation; and a supply unit that supplies current to the aforementioned electromagnetic actuator based on the aforementioned voltage command value. The aforementioned signal obtained from the aforementioned control unit is at least one of the aforementioned deviation output from the aforementioned calculation unit, the aforementioned voltage command value output from the aforementioned generation unit, and the aforementioned current output from the aforementioned supply unit.

11. A lithography apparatus for forming a pattern on a substrate, comprising: a stage for holding the substrate or original; and a control device as claimed in claim 1 for controlling the driving of the stage as a moving body.

12. A method of manufacturing an article, comprising: a forming process for forming a pattern on a substrate using a lithography apparatus as described in claim 11; a processing process for processing the substrate on which the pattern has been formed in the forming process; and a manufacturing process for manufacturing an article from the substrate on which the processing process has been performed.

13. A control method comprising: using an electromagnetic actuator for driving a moving body, and a detection coil for controlling the driving of the moving body by means of an output and a voltage value corresponding to the magnetic flux generated by the electromagnetic actuator; comprising: a correction procedure for outputting a correction signal by applying a correction value to the output of the detection coil; a conversion procedure for converting the correction signal into magnetic flux; and a control procedure for controlling the electromagnetic actuator based on the output obtained in the conversion procedure and a target magnetic flux; wherein in the correction procedure, the correction value is determined based on the signal obtained in the control procedure and the output obtained in the conversion procedure, such that the drift component generated in the output obtained in the conversion procedure is reduced.

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