Vibration reduction device, system, object production method and control method

Abstract

To provide a technique advantageous for appropriately determining a control parameter value of an air actuator in a vibration reduction device.SOLUTION: A vibration reduction device for reducing vibration of an object includes: a regulation member that regulates a position of the object; an actuator including a gas spring that supports the object in a release state where the regulation of the position of the object by using the regulation member is released and a valve that adjusts internal pressure of the gas spring; and a control section that controls the actuator. On the basis of responsiveness properties of the actuator measured in a regulation state where the position of the object is regulated by the regulation member, the control section determines a parameter value for controlling the actuator in the release state.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vibration reduction device, system, article manufacturing method, and control method. [Background technology]

[0002] In a lithography process, which is a manufacturing process for semiconductor devices and liquid crystal display devices, for example, an exposure apparatus may be used that transfers a pattern of an original (reticle or mask) to a substrate (such as a wafer or glass plate with a resist layer formed on the surface) via a projection optical system. In recent years, there has been a demand for extremely fine patterns in exposure apparatuses, but vibrations transmitted from the floor on which the exposure apparatus is installed to the apparatus body cause a decrease in the transfer accuracy and overlay accuracy of the pattern. For this reason, the exposure apparatus may be installed via a vibration isolator (vibration reduction device) to reduce the influence of floor vibration. Similarly, a configuration in which the main body is supported by a vibration isolator is also adopted in processing apparatuses such as high-precision measurement apparatuses, electron beam drawing apparatuses, and imprint apparatuses.

[0003] As a conventional vibration isolator, a so-called active type vibration isolator is known, which detects the vibration of a vibration isolator table by a vibration sensor and drives the vibration isolator table by an actuator in response to the detection signal. The active type vibration isolator can realize a well-balanced characteristic between vibration isolating performance and vibration damping performance, which is difficult to achieve with a passive vibration isolator composed only of a support mechanism having spring and damper characteristics. In the active type vibration isolator, an air actuator having a gas spring (air spring) and an adjustment valve for adjusting the internal pressure can generally be used. This is because the air actuator can easily generate a large thrust and can sufficiently support a heavy object such as a semiconductor manufacturing device body such as an exposure device. In addition, by using the air actuator, the natural frequency of the vibration isolator can be set to a low frequency of about several Hz, and sufficient vibration isolating performance against external vibration can be ensured. Patent Document 1 discloses the configuration and control method of the vibration isolator, and Patent Document 2 discloses an adjustment method of the vibration isolator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-148552 A [Patent Document 2] JP 2004-246661 A Summary of the Invention [Problem to be solved by the invention]

[0005] In an air actuator, the internal pressure of the gas spring is adjusted by a regulating valve, and a thrust is generated according to the internal pressure of the gas spring. The regulating valve can output a pressure to the gas spring within a range from the supply pressure of the high-pressure gas supplied to the regulating valve to the exhaust pressure of the air release, according to an input signal given to the regulating valve. That is, when the supply pressure supplied to the regulating valve changes, the pressure output to the gas spring can change due to the influence. In addition, air actuators have a large individual difference compared to other types of actuators. Therefore, in an active vibration isolation device using multiple air actuators as a means for imparting skyhook viscosity, it is necessary to provide a large stability margin for the control system in consideration of the supply pressure adjustment range and individual differences of the air actuators, and the skyhook viscosity can be reduced accordingly.

[0006] In order to accurately reduce the vibration of the vibration isolation table in such an anti-vibration apparatus, it is desirable to set appropriate control parameter values ​​for each air actuator. However, for example, in a configuration in which multiple air actuators are used to reduce the vibration of the vibration isolation table with multiple control axes, it may be difficult to appropriately determine the control parameter values ​​for each air actuator due to interference between the multiple axes.

[0007] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide an advantageous technique for appropriately determining control parameter values ​​for an air actuator in a vibration reduction device. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, a vibration reduction device as one aspect of the present invention is a vibration reduction device that reduces vibration of an object, and comprises a regulating member that regulates the position of the object, an actuator that includes a gas spring that supports the object in a released state in which the regulation of the position of the object by the regulating member is released, and a valve that adjusts the internal pressure of the gas spring, and a control unit that controls the actuator, wherein the control unit determines a parameter value for controlling the actuator in the released state based on the response characteristics of the actuator measured in the regulated state in which the position of the object is regulated by the regulating member.

[0009] 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. Effect of the Invention

[0010] According to the present invention, for example, it is possible to provide an advantageous technique for appropriately determining control parameter values ​​of an air actuator in a vibration reduction device. [Brief description of the drawings]

[0011] [Figure 1] A diagram showing an example of the configuration of a general vibration reduction device. [Diagram 2] A diagram showing the control system of a typical vibration reduction device. [Diagram 3] FIG. 1 is a diagram showing an example of a configuration and a control system of a vibration reduction device according to an embodiment of the present invention; [Figure 4] (a) Diagram showing the restricted state, (b) Diagram showing the lifted state [Diagram 5] A diagram showing the response characteristics of an air actuator [Figure 6] A diagram showing the relationship between the command value to the air valve and the time constant of the response characteristics. [Figure 7] A diagram showing the relationship between the command value to the air valve and the proportional gain of the response characteristics. [Figure 8]Flowchart showing how to determine the parameter values ​​of the PI compensator [Figure 9] FIG. 1 is a schematic diagram showing an example of the configuration of a system including a motion reduction apparatus and an exposure apparatus; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0013] In this specification and the accompanying drawings, directions are shown in an XYZ coordinate system with the vertical direction as the Z direction. The directions parallel to the X-axis, Y-axis, and Z-axis in the XYZ coordinate system are the X direction, the Y direction, and the Z direction, respectively, and the rotation around the X-axis, the Y axis, and the Z axis are θX, θY, and θZ, respectively. Control and drive (movement) regarding the X-axis, Y-axis, and Z-axis respectively mean control or drive (movement) regarding the direction parallel to the X-axis, the direction parallel to the Y axis, and the direction parallel to the Z axis. In addition, control or drive regarding the θX-axis, θY-axis, and θZ-axis respectively mean control or drive regarding the rotation around an axis parallel to the X-axis, the rotation around an axis parallel to the Y axis, and the rotation around an axis parallel to the Z axis.

[0014] First, a general vibration reduction device 100 that is the basis of the vibration reduction device according to the present invention will be described. Fig. 1 is a diagram showing an example of the configuration of a general vibration reduction device 100. The vibration reduction device 100 is a device that reduces vibration of a vibration isolation table 10 (object), and is an active type vibration isolation device that reduces vibration transmitted to the vibration isolation table 10 from a base such as a floor (not shown in Fig. 1) by using an air actuator 20. In the XYZ coordinate system in Fig. 1, the left-right direction of the device is the X direction, the depth direction of the device is the Y direction, and the height direction (vertical direction) of the device is the Z direction.

[0015] The vibration reduction device 100 includes a plurality of air actuators 20. The plurality of air actuators 20 are provided, for example, at the four corners of the vibration isolation table 10 having a rectangular parallelepiped shape. Each air actuator 20 is an actuator including an air spring 21 (gas spring) that supports the vibration isolation table 10 and an air valve 22 (adjustment valve) that adjusts the internal pressure of the air spring 21. Here, in the explanation of FIG. 1, the air spring 21 may be represented as "SU" and the air valve 22 may be represented as "AV". The suffixes "-1V" to "-4V" of "SU" and "AV" indicate the identification numbers of the air spring SU and the air valve AV for reducing the vibration of the vibration isolation table 10 in the vertical direction (Z direction). The suffixes "-1H" to "-4H" indicate the identification numbers of the air spring SU and the air valve AV for reducing the vibration of the vibration isolation table 10 in the horizontal directions (XY directions). In addition, those designated with "-1H" and "-3H" are configured to act on the vibration isolation table 10 in the Y direction, and those designated with "-2H" and "-4H" are configured to act on the vibration isolation table 10 in the X direction.

[0016] The vibration reduction device 100 includes a vibration detection unit 30 that detects vibrations of the vibration isolation table 10. In the present embodiment, the vibration detection unit 30 includes a position sensor 30a that detects the position (displacement) of the vibration isolation table 10 and an acceleration sensor 30b that detects the acceleration of the vibration isolation table 10, and a plurality of vibration detection units 30 may be provided at each location on the vibration isolation table 10. Here, in the explanation of FIG. 1, the position sensor 30a may be represented as "PS" and the acceleration sensor 30b may be represented as "AS". The suffixes "-1V" to "-3V" of "PS" and "AS" indicate the identification numbers of the position sensor PS and the acceleration sensor AS that perform detection in the vertical direction (Z direction). The suffixes "-1H" to "-3H" indicate the identification numbers of the position sensor PS and the acceleration sensor AS that perform detection in the horizontal direction (XY direction). Note that the sensors with "-1H" and "-3H" are configured to perform detection in the Y direction, and the sensors with "-2H" and "-4H" are configured to perform detection in the X direction. Moreover, each of the position sensor PS and the acceleration sensor AS is composed of only six elements, "-1V" to "-3V" and "-1H" to "-3H." This is because the rigid body motion of the vibration isolation table 10 has six degrees of freedom, and a minimum of six sensors are required to measure all the degrees of freedom of motion.

[0017] The vibration reduction device 100 includes a control unit 40 that controls each air actuator 20 based on the detection results of the vibration detection unit 30 (position sensor PS, acceleration sensor AS). The control unit 40 is configured, for example, by a computer (information processing device) having a processor such as a CPU (Central Processing Unit) and a storage unit such as a memory, and controls the process of reducing vibration of the vibration isolation table 10 using each air actuator 20. The control unit 40 may also be configured, for example, by a PLD (abbreviation for Programmable Logic Device) such as an FPGA (abbreviation for Field Programmable Gate Array), or an ASIC (abbreviation for Application Specific Integrated Circuit), or a general-purpose or dedicated computer with a program built in, or a combination of all or part of these.

[0018] The following description focuses on the components at the left front of the drawing, which are given the subscripts "-1V" and "-1H".

[0019] The air spring SU-1V supports the vibration isolation table 10 in the vertical direction (Z direction), and reduces (blocks) the transmission of vibration from the base (i.e., the floor on which the vibration reduction device 100 is installed) to the vibration isolation table 10 due to the vibration reduction (vibration blocking) property of the air spring. The air spring SU-1V is a support leg of the vibration isolation table 10, and at the same time, it plays the role of an actuator that applies a vibration-damping force to the vibration isolation table 10. The vibration-damping force is generated by actively controlling the internal pressure of the air spring SU-1V. For this purpose, the air spring SU-1V is provided with an air valve AV-1V. The air valve AV-1V is a pressure-controlled air valve that adjusts (controls) the internal pressure of the air spring SU-1V according to an input signal. In general, an air actuator (pneumatic actuator) that combines the air spring SU-1V and the air valve AV-1V generates a vibration-damping force with a first-order delay in response to an input signal to the air valve AV-1V.

[0020] On the other hand, the air spring SU-1H supports the vibration isolation table 10 in the horizontal direction (Y direction). The air spring SU-1H has vibration reducing characteristics and is used as an air actuator that applies a vibration damping force to the vibration isolation table 10 in cooperation with the air valve AV-1H, just like the air spring SU-1V, so detailed explanations will be omitted here.

[0021] The position sensor PS-1V is a position detector that detects the position of the vibration isolation table 10 in the vertical direction (Z direction) and is used to hold the vibration isolation table 10 at a predetermined position in the vertical direction. A position signal indicating the position of the vibration isolation table 10 detected by the position sensor PS-1V is provided to the control unit 40. The control unit 40 performs a feedback control of the air spring SU-1V by performing a predetermined compensation process based on the deviation between the position of the vibration isolation table 10 detected by the position sensor PS-1V and a position target value. The control unit 40 may include a compensator that generates a command value (input signal) to be input to the air valve AV-1V to adjust the internal pressure of the air spring SU-1V based on the deviation. The vibration isolation table 10 is held at a predetermined position by the operation of such a position feedback loop. The position sensor PS-1H is a position detector that detects the position of the vibration isolation table 10 in the horizontal direction (Y direction). The feedback control of the air spring SU-1H using the position sensor PS-1H is similar to the feedback control of the air spring SU-1V using the position sensor PS-1V, so a detailed description thereof will be omitted here.

[0022] The acceleration sensor AS-1V is an acceleration detection unit that detects the vibration acceleration of the vibration isolation table 10 in the vertical direction (Z direction) and is used to impart skyhook viscosity to the vibration isolation table 10 in the vertical direction. An acceleration signal indicating the acceleration of the vibration isolation table 10 detected by the acceleration sensor AS-1V is provided to the control unit 40. The control unit 40 performs feedback control of the air spring SU-1V by performing a predetermined compensation process based on the acceleration of the vibration isolation table 10 detected by the acceleration sensor AS-1V. The control unit 40 may include a compensator that generates a command value (input signal) to be input to the air valve AV-1V to adjust the internal pressure of the air spring SU-1V based on the acceleration of the vibration isolation table 10 detected by the acceleration sensor AS-1V. In addition, the acceleration sensor AS-1H is an acceleration detection unit that detects the vibration acceleration of the vibration isolation table 10 in the horizontal direction (Y direction) and is used to impart skyhook viscosity to the vibration isolation table 10 in the horizontal direction. The feedback control of the air spring SU-1H using the acceleration sensor AS-1H is similar to the feedback control of the air spring SU-1V using the acceleration sensor AS-1V, so a detailed description thereof will be omitted here.

[0023] Next, a control system of the general vibration reduction device 100 will be described. Fig. 2 is a diagram showing the control system of the general vibration reduction device 100. The control system of the general vibration reduction device 100 may include the air valve 22, the position sensor 30a, and the acceleration sensor 30b described above. The control system of the general vibration reduction device 100 may further include a position target generator 41, a subtractor 42, motion mode extraction calculators 43-44, compensators 45-46, an adder 47, a thrust distribution calculator 48, and a power amplifier 49. Each of the units 41-49 may be understood as a component of the control unit 40.

[0024] The rigid body motion of the vibration isolation table 10 is decomposed into a total of six motion modes, including translation directions X, Y, and Z of each axis and rotation directions θx, θy, and θz around each axis, when considered based on the XYZ coordinate system. A feedback loop is configured for each of these motion modes.

[0025] The position signals output from the position sensors 30a (PS-1V to PS-3V, PS-1H to PS-3H) are compared with and subtracted from predetermined target values ​​(R1V to R3V, R1H to R3H) output from the position target generator 41 by the subtractors 42. As a result, deviation signals (E1V to E3V, E1H to E3H) related to the position sensors 30a are output from the subtractors 42 and input to a position-related motion mode extraction calculator 43. The motion mode extraction calculator 43 is a calculator that converts each deviation signal into a motion mode deviation signal (Ex, Ey, Ez, Eθx, Eθy, Eθz). Note that Ex, Ey, Ez indicate deviations in the translation directions of the X-, Y-, and Z-axes, respectively, and Eθx, Eθy, and Eθz indicate deviations in the rotation directions around the X-, Y-, and Z-axes, respectively.

[0026] The acceleration signals output from each acceleration sensor 30b (AS-1V to AS-3V, AS-1H to AS-3H) are input to an acceleration-related motion mode extraction calculator 44. The motion mode extraction calculator 44 is a calculator that converts each acceleration signal into a motion mode acceleration signal (Ax, Ay, Az, Aθx, Aθy, Aθz).

[0027] The feedback loop is configured to apply a vibration suppression force of a motion mode to the vibration isolation table 10 after performing a predetermined compensation process on each of the deviation signal and acceleration signal of the motion mode. The deviation signal (Ex, Ey, Ez, Eθx, Eθy, Eθz) is input to a compensator 45 for each motion mode. Each compensator 45 adjusts the band of the position control of each control axis, and generates a control signal for each motion mode based on each deviation signal. On the other hand, the acceleration signal (Ax, Ay, Az, Aθx, Aθy, Aθz) is input to a compensator 46 for each motion mode. The compensator 46 adjusts the magnitude of the active viscosity to be applied to each control axis and limits the band, and generates a control signal for each motion mode based on each acceleration signal. The compensator 46 is a gain compensator for viscosity, and functions to apply viscosity to the vibration isolation table 10 based on each acceleration signal (Ax, Ay, Az, Aθx, Aθy, Aθz). The viscosity is applied by feedback of the velocity signal. Therefore, in the case of feedback of an acceleration signal, the compensator 46 may be configured to be an integrator together with the actuator.

[0028] Each signal from the compensator 46 is added with negative polarity by each adder 47 to each signal from the compensator 45 in order to generate a thrust in a direction that suppresses the acceleration. The signal obtained by this addition is converted by a thrust distribution calculator 48 into a command signal that is given to each air valve 22 (AV-1V to AV-3V, AV-1H to AV-3H) to adjust the internal pressure of each air spring SU. The command signal is given to the air valve 22 after being converted from a digital signal to a current signal by a power amplifier 49.

[0029] Incidentally, in the air actuator 20, the internal pressure of the air spring 21 is adjusted by the air valve 22, and a thrust is generated according to the internal pressure of the air spring 21. The air valve 22 can output to the air spring 21 a pressure within a range from the supply pressure of the high-pressure gas supplied to the air valve 22 to the exhaust pressure of the air release, according to an input signal given to the air valve 22. That is, when the supply pressure supplied to the air valve 22 changes, the pressure output to the air spring 21 can change due to the influence of the change. Also, the air actuator 20 has a large individual difference compared to other types of actuators. Therefore, in the active vibration reduction device 100 using multiple air actuators 20 as a means for imparting skyhook viscosity, it is necessary to take a large stability margin of the control system into consideration of the adjustment range of the supply pressure and the individual differences of the air actuators 20. And the skyhook viscosity can be reduced accordingly.

[0030] In order to accurately reduce the vibration of the vibration isolation table 10 in such a vibration reduction device 100, it is desirable to appropriately set control parameter values ​​for each air actuator 20. However, for example, in a configuration in which multiple air actuators 20 are used to reduce the vibration of the vibration isolation table 10 in multiple control axes (e.g., six degrees of freedom), it may be difficult to appropriately determine control parameter values ​​for each air actuator 20 due to interference between the multiple axes.

[0031] Therefore, the vibration reduction device 100a according to one embodiment of the present invention acquires the response characteristics of the air actuator 20 in a state in which the position of the vibration isolation table 10 is restricted by a restricting member 12 (hereinafter, sometimes referred to as a restricted state) which will be described later. Then, based on the acquired response characteristics of the air actuator 20, a parameter value for controlling the air actuator 20 in a state in which the restriction of the position of the vibration isolation table 10 by the restricting member 12 is released (hereinafter, sometimes referred to as a released state) is determined.

[0032] A vibration reduction device 100a according to an embodiment of the present invention will be described below. The following description will focus on the air actuator 20 (air spring SU-1V, air valve AV-1V) at the front left of the drawing in Fig. 1, which is given the suffix "-1V". Fig. 3 is a diagram showing an example of the configuration and control system of the vibration reduction device 100a of this embodiment. Fig. 3 shows the configuration after the thrust distribution calculator 48 of the control system shown in Fig. 2, and omits the configuration before the thrust distribution calculator 48.

[0033] The vibration reduction device 100a of this embodiment may include an air actuator 20 and a control unit 40, similar to the general vibration reduction device 100 described above. The air actuator 20 includes an air spring 21 (gas spring) that is disposed between the vibration isolation table 10 and a base 11 (e.g., a floor) and supports the vibration isolation table 10, and an air valve 22 (adjustment valve) that adjusts the internal pressure of the air spring 21. The vibration reduction device 100a of this embodiment may further include a regulating member 12, a pressure detection unit 50, a PI compensator 61, a characteristics acquirer 62, and a signal switcher 63. The PI compensator 61, the characteristics acquirer 62, and the signal switcher 63 may be understood as components of the control unit 40.

[0034] The regulating member 12 is a member that regulates the position (displacement) of the vibration isolation table 10. The regulating member 12 may be configured as a member that fixes the position of the vibration isolation table 10. In the case of this embodiment, the regulating member 12 may be configured as a mounting table on which the vibration isolation table 10 is placed when the internal pressure of the air spring 21 of the air actuator 20 is reduced. In this case, the regulated state is a state in which the vibration isolation table 10 is placed on the regulating member 12 as a mounting table, that is, a state in which the vibration isolation table 10 is seated on the regulating member 12 (seated state), as shown in FIG. 4(a). The regulated state may be a state in which the air spring 21 and the vibration isolation table 10 are not in contact with each other. In addition, the released state is a state in which the vibration isolation table 10 is separated from the regulating member 12 as a mounting table, floats, and is supported by the air spring 21 of the air actuator 20 (floating state), as shown in FIG. 4(b). The released state may be a state in which the air spring 21 and the vibration isolation table 10 are in contact with each other. 4(a)-(b) are diagrams showing the positional relationship between the vibration isolation table 10, the air spring 21 and the regulating member 12, with FIG. 4(a) showing the regulated state (seated state) and FIG. 4(b) showing the released state (floating state).

[0035] The pressure detection unit 50 detects the internal pressure of the air spring 21 of the air actuator 20. The pressure detection unit 50 may be configured to directly detect the internal pressure of the air spring 21, or may be configured to detect the pressure in a communication passage connecting the air spring 21 and the air valve 22 as the pressure of the air spring 21, as shown in FIG.

[0036] As described above, the control unit 40 further includes the PI compensator 61, the characteristics acquirer 62, and the signal switcher 63. As described above, only the configuration after the thrust distribution calculator 48 is shown in FIG.

[0037] The thrust distribution calculator 48 converts the feedback control signal (signal from the adder 47) of the vibration reduction device 100a into a command signal that is given to the air valve 22 to adjust the internal pressure of the air spring 21. The command signal output from the thrust distribution calculator 48 is given to the air valve 22 via a PI compensator 61 and a power amplifier 49. The PI compensator 61 is a compensator for correcting (adjusting) the command signal output from the thrust distribution calculator 48 so that individual differences in the individual axes of the air actuator 20 are adjusted. It is desirable that the characteristics of the combined PI compensator 61 and the air actuator 20 be integral characteristics, since this can be easily converted into a velocity signal for imparting viscosity to the vibration isolation table 10 when feeding back an acceleration signal.

[0038] In the vibration reduction device 100a (control unit 40) of this embodiment, a signal switcher 63 is disposed between the PI compensator 61 and the power amplifier 49. The signal switcher 63 switches the signal to be input to the air actuator 20 between the input signal Din output from the characteristic acquirer 62 and the command signal output from the PI compensator 61 in response to a switching signal Sw from the characteristic acquirer 62. The input signal Din is a signal given to the air actuator 20 (air valve 22) to acquire the response characteristic of the air actuator 20, and may be, for example, a step signal. The response characteristic (step response characteristic) of the air actuator 20 may be acquired (observed) by the pressure detection unit 50 detecting the internal pressure of the air spring 21 when the input signal Din (step signal) output from the characteristic acquirer 62 is given to the air valve 22. The characteristic acquirer 62 acquires the response characteristic of the air actuator 20 based on the detection signal Dout (observation signal) of the pressure detection unit 50 with respect to the input signal Din. Then, the characteristic obtainer 62 determines parameter values ​​of the PI compensator 61 based on the obtained response characteristics of the air actuator 20, and sets the parameter values ​​in the PI compensator 61. Here, the parameter values ​​of the PI compensator 61 include at least one of the proportional gain and the time constant of the PI compensator 61.

[0039] Next, a description will be given of a method for determining the parameter values ​​of the PI compensator 61. The parameter values ​​of the PI compensator 61 can be determined by the control unit 40 (characteristics obtainer 62).

[0040] In this embodiment, the response characteristic of the air actuator 20 is acquired in a restricted state in which the position of the vibration isolation table 10 is restricted by the restricting member 12. Then, based on the acquired response characteristic of the air actuator 20, a parameter value of the PI compensator 61 for controlling the air actuator 20 in a released state in which the restriction of the position of the vibration isolation table 10 by the restricting member 12 is released is determined. The response characteristic of the air actuator 20 is a characteristic of the internal pressure of the air spring 21 with respect to an input signal to the air valve 22, and is measured (acquired) as a first-order lag response characteristic. A simple method for measuring the response characteristic of the air actuator 20 is to use the response of the internal pressure of the air spring 21 when a step signal is input to the air valve 22, that is, the step response. An example of measuring the response characteristic of the air actuator 20 by the step response will be described below.

[0041] Fig. 5 shows the response characteristic of the air actuator 20. The response characteristic shown in Fig. 5 is a characteristic (step response characteristic) that indicates the change over time in the internal pressure of the air spring 21 detected by the pressure detection unit 50 when a step signal is input to the air valve 22 of the air actuator 20. The response of the air spring 21 can generally be approximated by a first-order lag, so that the transfer function G a can be expressed by the following equation (1).

[0042]

number

[0043] In this case, it is generally known that the proportional gain Ka is obtained from the final step value based on the response characteristics to the step signal (step input), and the time constant Ta is obtained from the elapsed time when the pressure value of the air spring 21 becomes 63.2% of the final step value. The final step value can be defined, for example, as the value after five times the maximum time constant among the assumed time constants has elapsed (99.3% value in the case of first order lag). The elapsed time can be defined as the time elapsed from the time when the measurement of the step response characteristics started, i.e., the time elapsed from the time when the input of the step signal started.

[0044] In contrast, the transfer function G PI The proportional gain is "K P "Integration time "T I ", then it can be expressed by the following equation (2).

[0045]

number

[0046] Therefore, by combining equations (1) and (2), the transfer function is expressed by the following equation (3).

[0047]

number

[0048] And the integral time T I When the integral time T is adjusted to be the same value as the time constant Ta, the equation (3) is expressed by the following equation (4). I It can be seen that by adjusting to the same value as the time constant Ta, an integrator can be obtained.

[0049]

number

[0050] Here, when attempting to measure the step response characteristics of the air actuator 20 in the released state (floating state), depending on the step signal input to the air valve 22, the vibration isolation table 10 may move beyond the movable stroke range and collide with other components in the device. Therefore, in this embodiment, the step response characteristics of the air actuator 20 are measured using a step signal that lowers the internal pressure of the air spring 21 compared to normal control so that the vibration isolation table 10 is placed on the regulating member 12 in a regulated state (seated state). However, in this case, a step signal with a command value range outside the command value range used in normal control is used. Therefore, the parameter value of the PI compensator 61 obtained based on the step response characteristics measured in the regulated state is slightly shifted from the parameter value of the PI compensator 61 that can accurately reduce the vibration of the vibration isolation table 10 within the command value range of normal control. The normal control refers to active control of the air actuator 20 that is performed to reduce the vibration of the vibration isolation table 10 in the released state (floating state).

[0051] In order to reduce the deviation of the parameter values, for example, it is preferable to determine the parameter values ​​of the PI compensator 61 based on the response characteristics of the air actuator 20 measured when at least two different types of inputs are applied to the air valve 22 in the restricted state. That is, it is preferable to determine the parameter values ​​of the PI compensator 61 based on the response characteristics (first response characteristics) measured when a first input is applied to the air valve 22 in the restricted state and the response characteristics (second response characteristics) measured when a second input is applied to the air valve 22 in the restricted state. The first input is, for example, an input that changes the command value in a first range that is lower than the range of command values ​​used in normal control (released state). The second input is, for example, an input that is different from the first input and that changes the command value in a second range that is lower than the range of command values ​​used in normal control (released state) and different from the first range. In the following, a command value that is changed within a first range as a first input may be referred to as a "first command value range," and a command value that is changed within a second range as a second input may be referred to as a "second command value range."

[0052] Fig. 6 shows the relationship between the command value to the air valve 22 and the time constant Ta of the response characteristic (hereinafter, sometimes referred to as the time constant characteristic). The time constant characteristic generally shows a curved shape that is convex upwards, and when the supply air pressure (input pressure) supplied to the air valve 22 is changed, the peak position can change accordingly. In the vibration reduction device 100a of this embodiment, as shown in Fig. 6, the supply air pressure to the air valve 22 is set so that the portion of the curve showing the time constant characteristic that has a shape close to linear overlaps with the command value range b used in normal control (released state). Note that, hereinafter, the command value range b used in normal control may be referred to as the "normal command value range b".

[0053] The first command value range a1 can be selected (set) from a portion of the curve representing the time constant characteristic that has a shape close to linear so as to be lower than the normal command value range b. Then, the first response characteristic is measured by operating the air valve 22 in the first command value range a1, and a time constant T1 (first characteristic value) is obtained from the first response characteristic. Similarly, the second command value range a2 can be selected (set) from a portion of the curve representing the time constant characteristic that has a shape close to linear so as to be lower than the normal command value range b and different from the first command value range a1. Then, the second response characteristic is measured by operating the air valve 22 in the second command value range a2, and a time constant T2 (second characteristic value) is obtained from the second response characteristic.

[0054] An approximation function Ft (a linear function in this embodiment) is obtained from the time constants T1 and T2 obtained in this manner, and a time constant T3 (third characteristic value) of the response characteristics of the air actuator 20 in the normal command value range d is estimated based on this approximation function Ft. Then, the parameter value (time constant) of the PI compensator 61 can be determined based on the estimated time constant T3. In this embodiment, the estimated time constant T3 can be determined (set) as the parameter value (time constant) of the PI compensator 61 as is.

[0055] The proportional gain Ka as a parameter value of the PI compensator 61 can be determined in the same manner as the time constant Ta. FIG. 7 shows the relationship between the command value to the air valve 22 and the proportional gain Ka of the response characteristic (hereinafter, sometimes referred to as the gain characteristic). The first response characteristic is measured by operating the air valve 22 in the first command value range a1, and the proportional gain K1 (first characteristic value) is obtained from the first response characteristic. Similarly, the second response characteristic is measured by operating the air valve 22 in the second command value range a2, and the proportional gain K2 (second characteristic value) is obtained from the second response characteristic. An approximation function Fk (a linear function in this embodiment) is obtained from the proportional gain K1 and proportional gain K2 thus obtained, and a proportional gain K3 (third characteristic value) of the response characteristic of the air actuator 20 in the normal command value range d is estimated based on the approximation function Fk. Then, the parameter value (proportional gain) of the PI compensator 61 can be determined based on the estimated proportional gain K3. In the case of this embodiment, the estimated proportional gain K3 can be determined (set) as the parameter value (proportional gain) of the PI compensator 61 as it is.

[0056] Here, in this embodiment, a method for determining the parameter values ​​of the PI compensator 61 using a step response has been described, but the present invention is not limited to this. For example, a Bode diagram may be created by a sine sweep or random vibration, and the parameter values ​​(time constant, proportional gain) of the PI compensator 61 may be determined based on the Bode diagram.

[0057] Next, a description will be given of a flow for determining the parameter values ​​of the PI compensator 61. Fig. 8 is a flowchart showing a method for determining the parameter values ​​of the PI compensator 61. The flowchart in Fig. 8 can be executed by the control unit 40 (characteristics acquirer 62).

[0058] In step S10, the control unit 40 brings the vibration isolation table 10 into a restricted state in which the position of the vibration isolation table 10 is restricted by the restricting member 12. For example, the control unit 40 controls the air valve 22 to reduce the internal pressure of the air spring 21 so that the vibration isolation table 10 is placed on the restricting member 12.

[0059] In step S11, the control unit 40 measures a first response characteristic by operating the air valve 22 in a first command value range. For example, the control unit 40 can measure the first response characteristic by having the pressure detection unit 50 detect the internal pressure of the air spring 21 when the air valve 22 is operated in the first command value range. Next, in step S12, the control unit 40 acquires a first characteristic value from the first command value range measured in step S11. The first characteristic value is an item to be determined as a parameter value of the PI compensator 61, and is at least one of a time constant and a proportional gain.

[0060] In step S13, the control unit 40 measures the second response characteristic by operating the air valve 22 in the second command value range. For example, the control unit 40 can measure the second response characteristic by having the pressure detection unit 50 detect the internal pressure of the air spring 21 when the air valve 22 is operated in the second command value range. Next, in step S14, the control unit 40 acquires a second characteristic value from the second command value range measured in step S13. The second characteristic value, like the first characteristic value, is an item to be determined as a parameter value of the PI compensator 61, and is at least one of a time constant and a proportional gain.

[0061] In step S15, the control unit 40 estimates a third characteristic value of the response characteristic of the air actuator 20 in the normal command value range based on the first characteristic value acquired in step S12 and the second characteristic value acquired in step S14. For example, the control unit 40 creates an approximation function of the first characteristic value and the second characteristic value, and estimates the third characteristic value based on the approximation function. A linear function may be used as the approximation function. The third characteristic value, like the first characteristic value and the second characteristic value, is an item to be determined as a parameter value of the PI compensator 61, and is at least one of a time constant and a proportional gain.

[0062] In step S16, the control unit 40 determines a parameter value of the PI compensator 61 based on the third characteristic value estimated in step S15. For example, the control unit 40 can determine the third characteristic value estimated in step S15 as the parameter value of the PI compensator 61 as it is.

[0063] In step S17, the control unit 40 sets the vibration isolation table 10 to a released state in which the restriction of the position of the vibration isolation table 10 by the restricting member 12 is released. For example, the control unit 40 controls the air valve 22 to increase the internal pressure of the air spring 21 so that the vibration isolation table 10 separates from the restricting member 12 and floats up.

[0064] As described above, the vibration reduction device 100a of this embodiment acquires the response characteristics of the air actuator 20 in the restricted state, and determines the parameter values ​​(parameter values ​​of the PI compensator 61) for controlling the air actuator 20 in the released state based on the response characteristics. This makes it possible to appropriately determine the parameter values ​​for controlling the air actuator 20.

[0065] <System embodiment> An embodiment of the system according to the present invention will be described. The system includes the vibration reduction device 100a and a processing device for processing a member. The processing device can be placed on an object (on the vibration isolation table 10) whose vibration is reduced by the vibration reduction device 100a. Examples of the processing device include a lithography device that forms a pattern on a substrate as a member, a measurement device that measures the member, and a processing device that processes the member. Examples of the lithography device include an exposure device that exposes the substrate to light and transfers the pattern of the original onto the substrate, a molding device (imprint device, flattening device) that uses a mold to mold a composition on the substrate, and a drawing device that uses a charged particle beam to form a pattern on the substrate. The following describes an example of a system having an exposure device as a processing device.

[0066] FIG. 9 is a schematic diagram showing a configuration example of a system STM including a vibration reduction device 100a and an exposure device 200. The configuration and control of the vibration reduction device 100a have been described above, so a description thereof will be omitted here. The exposure device 200 transfers a pattern formed on an original R (reticle 5) to a substrate S, for example, by a step-and-repeat method or a step-and-scan method. The exposure device 200 may include an illumination optical system 201, an original stage 202, a projection optical system 203, a substrate stage 204, and a control unit 206. In the exposure device 200, the illumination optical system 201, the original stage 202, the projection optical system 203, and the substrate stage 204 function as a processing device that processes the substrate S as a member. The control unit 206 of the exposure device 200 and the control unit 40 of the vibration reduction device 100a may be configured as an integrated unit or may be configured separately.

[0067] <Embodiment of the article manufacturing method> The above-mentioned system can be used to implement an article manufacturing method for manufacturing various articles (semiconductor IC elements, liquid crystal display elements, MEMS, etc.). The article manufacturing method in the embodiment of the present invention is suitable for manufacturing articles such as devices (semiconductor elements, magnetic storage media, liquid crystal display elements, etc.). Such an article manufacturing method includes a processing step of processing a member by a processing device of the above-mentioned system, and a manufacturing step of manufacturing an article from the member that has undergone the processing step. Furthermore, such an article manufacturing method may include other well-known steps (oxidation, film formation, deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The article manufacturing method in the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to the conventional methods.

[0068] <Summary of the embodiment> The disclosure of this specification includes at least the following vibration reduction devices, systems, article manufacturing methods, and control methods. (Item 1) A vibration reduction device for reducing vibration of an object, comprising: A regulating member that regulates the position of the object; an actuator including a gas spring that supports the object in a released state in which the restriction of the position of the object by the restricting member is released, and a valve that adjusts an internal pressure of the gas spring; A control unit that controls the actuator; Equipped with The control unit determines a parameter value for controlling the actuator in the released state based on the response characteristics of the actuator measured in a regulated state in which the position of the object is regulated by the regulating member. (Item 2) The vibration reduction device described in item 1, characterized in that the control unit determines the parameter value based on a first response characteristic which is a response characteristic of the actuator when a first input is applied in the regulated state, and a second response characteristic which is a response characteristic of the actuator when a second input different from the first input is applied in the regulated state. (Item 3) the first response characteristic is a response characteristic of the actuator measured when a command value is changed within a first range as the first input, 3. The vibration reduction device according to item 2, wherein the second response characteristic is a response characteristic of the actuator measured when a command value is changed as the second input within a second range different from the first range. (Item 4) The vibration reduction device described in item 2 or 3, characterized in that the control unit estimates a characteristic value of the response characteristic of the actuator within a range of command values ​​used in the released state as a third characteristic value based on a first characteristic value obtained from the first response characteristic and a second characteristic value obtained from the second response characteristic, and determines the parameter value based on the third characteristic value. (Item 5) 5. The vibration reduction device according to item 4, wherein the control unit estimates the third characteristic value based on an approximation function of the first characteristic value and the second characteristic value. (Item 6) 6. The vibration reduction device according to item 5, wherein the approximation function is a linear function. (Item 7) Further comprising a pressure detection unit that detects the internal pressure of the gas spring, 7. The vibration reduction device according to any one of items 1 to 6, wherein the control unit measures a response characteristic of the actuator based on a detection result of the pressure detection unit. (Item 8) the control unit includes a compensator for correcting a command signal of the actuator, 8. The vibration reduction device according to any one of items 1 to 7, wherein the parameter value is at least one of a proportional gain and a time constant of the compensator. (Item 9) 9. The vibration reduction device according to item 8, wherein the compensator is a PI compensator. (Item 10) 10. The vibration reduction device according to any one of items 1 to 9, wherein the restricted state is a state in which the internal pressure of the gas spring is smaller than that of the released state. (Item 11) the regulating member is configured as a member on which the object is placed, The vibration reduction device described in any one of items 1 to 10, characterized in that the released state is a state in which the object is separated from the regulating member and floats up, and the regulated state is a state in which the object is placed on the regulating member. (Item 12) A vibration reduction device according to any one of items 1 to 11, A processing device for processing the member, A system, comprising: the processing device disposed on an object whose vibrations are to be reduced by the vibration reduction device. (Item 13) A processing step of processing a member by a processing device of the system according to item 12; a manufacturing process for manufacturing an article from the member that has been subjected to the processing process; A method for manufacturing an article, comprising: (Item 14) 1. A control method for a vibration reduction device that reduces vibration of an object by using an actuator including a gas spring that supports an object and a valve that adjusts an internal pressure of the gas spring, comprising: a measuring step of measuring a response characteristic of the actuator in a restricted state in which a position of the object is restricted; a determination step of determining, based on the response characteristic measured in the measurement step, parameter values ​​for controlling the actuator in a release state in which restriction on the position of the object is released; A control method comprising:

[0069] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0070] 10: vibration isolation table, 11: base (floor), 12: regulating member, 20: air actuator, 21: air spring, 22: air valve, 30: vibration detection unit, 40: control unit, 50: pressure detection unit, 61: PI compensator, 62: characteristic acquisition unit, 63: signal switch 63, 100, 100a: vibration reduction device

Claims

1. A vibration reduction device for reducing vibration of an object, comprising: A regulating member that regulates the position of the object; an actuator including a gas spring that supports the object in a released state in which the restriction of the position of the object by the restricting member is released, and a valve that adjusts an internal pressure of the gas spring; A control unit that controls the actuator; Equipped with The control unit determines a parameter value for controlling the actuator in the released state based on the response characteristics of the actuator measured in a regulated state in which the position of the object is regulated by the regulating member.

2. The vibration reduction device of claim 1, characterized in that the control unit determines the parameter value based on a first response characteristic which is the response characteristic of the actuator when a first input is applied in the regulated state, and a second response characteristic which is the response characteristic of the actuator when a second input different from the first input is applied in the regulated state.

3. the first response characteristic is a response characteristic of the actuator measured when a command value is changed within a first range as the first input, 3. The vibration reduction device according to claim 2, wherein the second response characteristic is a response characteristic of the actuator measured when a command value is changed as the second input within a second range different from the first range.

4. The vibration reduction device of claim 2, characterized in that the control unit estimates a characteristic value of the response characteristic of the actuator within the range of command values ​​used in the released state as a third characteristic value based on a first characteristic value obtained from the first response characteristic and a second characteristic value obtained from the second response characteristic, and determines the parameter value based on the third characteristic value.

5. The vibration reducing device according to claim 4 , wherein the control unit estimates the third characteristic value based on an approximation function of the first characteristic value and the second characteristic value.

6. 6. The vibration reduction device according to claim 5, wherein the approximation function is a linear function.

7. Further comprising a pressure detection unit that detects the internal pressure of the gas spring, 2. The vibration reduction device according to claim 1, wherein the control unit measures a response characteristic of the actuator based on a detection result of the pressure detection unit.

8. the control unit includes a compensator for correcting a command signal of the actuator, 2. The vibration reduction device according to claim 1, wherein the parameter value is at least one of a proportional gain and a time constant of the compensator.

9. 9. The vibration reduction device according to claim 8, wherein the compensator is a PI compensator.

10. 2. The vibration reduction device according to claim 1, wherein the restricted state is a state in which the internal pressure of the gas spring is smaller than that of the released state.

11. the regulating member is configured as a member on which the object is placed, 2. The vibration reduction device according to claim 1, wherein the released state is a state in which the object is separated from the regulating member and floats, and the regulated state is a state in which the object is placed on the regulating member.

12. A vibration reduction device according to any one of claims 1 to 11, A processing device for processing the member, A system, comprising: the processing device disposed on an object whose vibrations are to be reduced by the vibration reduction device.

13. A processing step of processing the workpiece by a processing device of the system of claim 12; a manufacturing process for manufacturing an article from the member that has been subjected to the processing process; A method for manufacturing an article, comprising:

14. 1. A control method for a vibration reduction device that reduces vibration of an object by using an actuator including a gas spring that supports an object and a valve that adjusts an internal pressure of the gas spring, comprising: a measuring step of measuring a response characteristic of the actuator in a restricted state in which a position of the object is restricted; a determination step of determining, based on the response characteristic measured in the measurement step, parameter values ​​for controlling the actuator in a release state in which restriction on the position of the object is released; A control method comprising:

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