JP2010039004A - Stage device, exposure apparatus and stage control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To synchronously move both of a substrate and a mask with high accuracy at a high speed. <P>SOLUTION: A stage device includes a first control system 100 having two degrees of freedom including a feedforward control unit 102 and a feedback control unit 103 for controlling the position of a plate stage PST, and a second control system 200 having two degrees of freedom comprising a feedforward control unit 202 and a feedback control unit 203 controlling the position of a mask stage MST. The second control system 200 having two degrees of freedom carries out control based on the position of the plate stage PST, and the feedforward control units 102 and 202 carries out complete follow-up control. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a stage apparatus, an exposure apparatus, and a stage control method.

  Conventionally, for example, in a process of manufacturing a liquid crystal display (generally called a flat panel display), an exposure apparatus is often used to form elements such as transistors and diodes on a substrate (glass substrate). In this exposure apparatus, a resist-coated substrate is placed on a holder of a stage device, and a fine circuit pattern drawn on a mask is transferred to the substrate via an optical system such as a projection lens. In recent years, for example, step-and-scan type exposure apparatuses are often used (see, for example, Patent Document 1).

  A step-and-scan type exposure apparatus is a pattern formed on a mask while the mask and the substrate are moved synchronously with respect to the projection optical system while irradiating the mask with slit-shaped exposure light. This is an exposure apparatus that sequentially transfers a portion to a shot area of a substrate and moves the substrate stepwise to transfer the pattern to another shot area each time pattern transfer to one shot area is completed.

  Therefore, in the step-and-scan type exposure apparatus, in order to perform pattern transfer to a plurality of shot areas, the substrate and the mask are each driven by independent stage devices, and in pattern transfer to one shot area, It is necessary to control the stage devices for the substrate and the mask so that the substrate and the mask move synchronously.

Conventionally, as a control method for controlling the two stage devices so that the substrate and the mask move synchronously, a master-slave system is configured with the substrate side as the master and the mask side as the slave, and the mask stage device (slave) ) Is controlled only by feedback control in which the actual position of the substrate is set as the target position and the mask position follows the target position.
JP 2000-0773313 A

  When the above conventional control method is used, since the mask stage device as a slave is controlled only by feedback control, the performance of the mask position following the substrate position depends exclusively on the performance of the feedback controller. It becomes. Therefore, even if the control target (substrate stage and mask stage) is nominal, if the feedback controller is not sufficiently high-performance, it is impossible to control the substrate and the mask to move synchronously with high accuracy and high speed. There was a problem that it was possible.

  The present invention has been made in view of the above points, and an object thereof is to provide a stage apparatus, an exposure apparatus, and a stage control method capable of synchronously moving a substrate and a mask with high accuracy and high speed. It is in.

  The present invention has been made to solve the above-described problems, and is a stage device that drives by synchronizing the positions of the first stage and the second stage, and controls the position of the first stage. First two degrees of freedom control means comprising forward control means and first feedback control means, and second two degrees of freedom comprising second feedforward control means and second feedback control means for controlling the position of the second stage. A control unit, wherein the second two-degree-of-freedom control unit performs control based on the position of the first stage, and the first and second feedforward control units perform complete tracking control. Device.

  In addition, the stage apparatus includes a state prediction unit that predicts a state of the first stage including at least values related to position and velocity, and the second feedforward control unit includes the first prediction unit predicted by the state prediction unit. The position of the second stage is controlled based on the state of one stage.

  The state predicting means predicts the state of the first stage ahead by the dead time in the control by the first and second two-degree-of-freedom control means.

  In addition, the stage apparatus includes a calculation unit that calculates at least a value related to a speed from a difference between the current and past positions of the first stage, and the second feedforward control unit includes a position of the first stage. And the position of the second stage is controlled based on at least a value related to the speed of the first stage calculated by the calculating means.

  The second feedback control means feedback-controls the position of the second stage based on the position of the first stage.

  Further, the present invention provides an exposure apparatus that exposes a mask pattern held on a mask stage onto a photosensitive substrate held on a substrate stage, wherein the substrate stage is any one of the first stages, and the mask stage is An exposure apparatus as any one of the second stages.

  Further, the present invention provides a first two-degree-of-freedom control means comprising a first feedforward control means and a first feedback control means for controlling the position of the first stage, and a second feedforward for controlling the position of the second stage. A stage control method for a stage apparatus, comprising: a second two-degree-of-freedom control means comprising a control means and a second feedback control means, and driving the first stage and the second stage in synchronization with each other, In the stage control method, the second two-degree-of-freedom control unit performs control based on the position of the first stage, and the first and second feedforward control units perform complete tracking control.

  According to the present invention, since complete follow-up control is performed by the feedforward control means, if the control target is nominal, the two stages can be moved completely synchronously, and based on the position of the first stage (master). Since the position of the second stage (slave) is controlled, the two stages can be moved synchronously with high precision even when the controlled object fluctuates, such as when a disturbance occurs.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of an exposure apparatus 10 according to an embodiment. The exposure apparatus 10 applies a mask M on which a liquid crystal display element pattern is formed and a glass plate (hereinafter referred to as “plate”) P as a substrate held by a plate stage PST to a projection optical system PL in a predetermined manner. The pattern formed on the mask M is transferred onto the plate P by performing relative scanning in the same direction at the same speed along the scanning direction (here, the X-axis direction (left and right direction in the drawing) in FIG. 1). This is a scanning exposure apparatus for liquid crystal of the same size batch transfer type.

  The exposure apparatus 10 illuminates a predetermined slit-shaped illumination area (a rectangular area or an arc-shaped area elongated in the Y-axis direction (perpendicular to the plane of FIG. 1)) on the mask M with exposure illumination light IL. A system IOP, a mask stage MST that holds the mask M on which the pattern is formed and moves in the X-axis direction, a projection optical system PL that projects the exposure illumination light IL transmitted through the illumination area portion of the mask M onto the plate P, A main body column 12, an anti-vibration table (not shown) for removing vibration from the floor to the main body column, a control device 11 for controlling both the stages MST and PST, and the like are provided.

  The illumination system IOP includes, for example, a light source unit, a shutter, a secondary light forming optical system, a beam splitter, a condensing lens system, a field stop (blind), and an image formation as disclosed in Japanese Patent Laid-Open No. 9-320956. The slit illumination area on the mask M, which is composed of a lens system and the like (both not shown) and is placed and held on the mask stage MST described below, is illuminated with uniform illuminance.

  The mask stage MST is levitated and supported above the upper surface of the upper surface plate 12a constituting the main body column 12 by a not-shown air pad via a clearance of about several μm, and is driven in the X-axis direction by the drive mechanism 14. The

  Here, a linear motor is used as the driving mechanism 14 for driving the mask stage MST, and this driving mechanism is hereinafter referred to as a linear motor 14. The stator 14a of the linear motor 14 is fixed to the upper part of the upper surface plate 12a and extends along the X-axis direction. The mover 14b of the linear motor 14 is fixed to the mask stage MST. The position of the mask stage MST in the X-axis direction is determined at a predetermined resolution with reference to the projection optical system PL by a mask stage position measuring laser interferometer (hereinafter referred to as “mask interferometer”) 18 fixed to the main body column 12. For example, it is always measured with a resolution of about several nm. The X-axis position information of the mask stage MST measured by the mask interferometer 18 is supplied to the control device 11.

  The projection optical system PL is disposed below the upper surface plate 12 a of the main body column 12 and is held by a holding member 12 c constituting the main body column 12. Here, as the projection optical system PL, an apparatus that projects an equal-size erect image is used. Therefore, when the slit illumination area on the mask M is illuminated by the exposure illumination light IL from the illumination system IOP, an equal-magnification image (partial upright image) of the circuit pattern of the illumination area is displayed on the plate P. It is projected onto an exposure area conjugate to the illumination area. For example, as disclosed in Japanese Patent Application Laid-Open No. 7-57986, the projection optical system PL may be configured by a plurality of sets of equal-magnification projection optical system units.

  Further, a focus position detection system (not shown) configured to measure the position of the plate P in the Z direction, for example, an autofocus sensor (not shown) configured by a CCD or the like is fixed to the holding member 12c that holds the projection optical system PL. . The Z position information of the plate P from the focal position detection system is supplied to the control device 11. The control device 11 projects the Z position of the plate P based on the Z position information during scanning exposure, for example. An autofocus operation is performed to match the PL image plane.

  The plate stage PST is disposed below the projection optical system PL, and is levitated and supported by a not-shown air pad above the upper surface of the lower surface plate 12b constituting the main body column 12 via a clearance of about several μm. The plate stage PST is driven in the X-axis direction by a linear motor 16 as a drive mechanism.

  The stator 16a of the linear motor 16 is fixed to the lower surface plate 12b and extends along the X-axis direction. A movable element 16b as a movable part of the linear motor 16 is fixed to the bottom of the plate stage PST. The plate stage PST includes a moving table 22 to which the mover 16b of the linear motor 16 is fixed, a Y driving mechanism 20 mounted on the moving table 22, and a plate P provided on the Y driving mechanism 20 on the plate P. The plate table 19 to hold | maintain is provided.

  The position of the plate table 19 in the X-axis direction is always measured by a plate interferometer 25 fixed to the main body column 12 with a predetermined resolution, for example, a resolution of about several nm, with reference to the projection optical system PL. As the plate interferometer 25, here, two length measuring beams in the X-axis direction separated by a predetermined distance L in the Y-axis direction orthogonal to the X-axis direction (the direction orthogonal to the paper surface in FIG. 1) are used. A two-axis interferometer that irradiates the measurement axis is used, and the measurement value of each measurement axis is supplied to the control device 11.

  When the measured values of the length measuring axes of the plate interferometer 25 are X1 and X2, the position of the plate table 19 in the X-axis direction is obtained by X = (X1 + X2) / 2, and θZ = (X1-X2) / L The amount of rotation of the plate table 19 about the Z-axis can be obtained, but in the following description, the above X is output as the X position information of the plate table 19 from the plate interferometer 25 unless otherwise required. Shall be.

FIG. 2 is a cross-sectional view showing a detailed configuration of the plate stage PST.
As shown in the figure, a leveling unit 50 is provided between the lower surface (surface in the −Z direction) 19a of the plate table 19 and the Y movable element 20a. A plurality of, for example, three leveling units 50 are arranged, and the position of the plate table 19 (position in the Z direction, position in the θX direction, and This unit controls the position in the θY direction. That is, by applying a predetermined force to the plate table 19 by these three leveling units 50, the position in the Z direction, the position in the θX direction, and the position in the θY direction of the plate table 19 can be adjusted.

FIG. 3 is a diagram illustrating a configuration of the leveling unit 50. Since each leveling unit 50 has the same configuration, one of them will be described as an example.
The leveling unit 50 includes a cam member 51, a guide member 52, a cam moving mechanism 53, a support member 54 provided on the Y movable element 20a, and a bearing member 55 provided on the plate table 19 side. ing.

  The cam member 51 is a member formed in a trapezoidal shape in cross section, and the lower surface 51a is a flat surface in the horizontal direction. The lower surface 51 a of the cam member 51 is supported by the guide member 52. The upper surface 51b of the cam member 51 is a flat surface provided to be inclined with respect to the horizontal plane. A screw hole 51 d is formed on one side surface 51 c of the cam member 51. The guide member 52 is provided on the support member 54 along the cam member 51, and extends in the left-right direction in the drawing.

  The cam moving mechanism 53 includes a servo motor 56, a ball screw 57, and a connecting member 58. The servo motor 56 rotates the shaft member 56 a based on a signal from the control device 11. Here, the shaft member 56a extends, for example, in the left-right direction in the figure. The ball screw 57 is connected to the shaft member 56a of the servomotor 56 via the connecting member 58, and the rotation of the shaft member 56a is transmitted. The ball screw 57 is provided with a screw portion in the left-right direction (the same direction as the axial direction of the rotation shaft of the servo motor 56) in the drawing, and the screw portion is formed in a screw hole 51d formed in the side surface 51c of the cam member 51. It is screwed. The shaft member 56a and the ball screw 57 are supported by the protrusions 54a and 54b of the support member 54, respectively.

  In this cam drive mechanism 53, the ball screw 57 is rotated by the rotation of the servo motor 56, and the cam member 51 screwed to the ball screw 57 by the rotation of the ball screw 57 is moved in the horizontal direction in the drawing along the guide member 52. It has become.

  The bearing member 55 has a hemispherical portion 55 a on the lower side in the figure, and the lower surface 55 b of the hemispherical portion 55 a is provided so as to contact the upper surface 51 b of the cam member 51. As the cam member 51 moves, the contact position between the lower surface 55b of the bearing member 55 and the upper surface 51b of the cam member 51 changes. When the contact position with the upper surface 51b changes, the lower surface The position of 55b in the Z direction changes. The position of the plate table 19 in the Z direction is finely adjusted by this change in position.

  The position of the plate table 19 in the Z direction can be detected by the detection device 59. A plurality of, for example, three detection devices 59 are provided for the plate table 19. Each detection device 59 includes, for example, an optical sensor 59a and a detected member 59b. The position of the detected member 59b is detected by the optical sensor 59a, so that the position of the plate table 19 in the Z direction is determined. It comes to detect. The optical sensor 59a is fixed to a protruding portion 20b provided on the Y movable element 20a. Therefore, the detection device 59 can detect the position and posture of the plate table 19 in the Z direction when the upper surface 20c of the Y movable element 20a is used as a reference. The position information detected by the detection device 59 is transmitted to the control device 11.

  Further, one end of the plate table 19 is connected to the protruding portion 20d on the Y movable element 20a by an elastic member 60. One end of the elastic member 60 is fixed to the end portion 19b of the plate table 19 by a fixing member 60a, and the other end is fixed to the protruding portion 20d by the fixing member 60b. The elastic member 60 allows the movement in the Z direction while suppressing the movement of the plate table 19 in the X direction and the Y direction.

  With the above-described configuration, the plate stage PST moves the moving table 22 (linear motor 16 so that the predetermined exposure area of the plate P held by the plate table 19 is located in the exposure area by the projection optical system PL. Can be moved in the X direction (positioning the X position), and the Y mover 20 can be moved in the Y direction with respect to the moving table 22 (positioning the Y position). At this time, the position of the plate P in the θZ direction may be adjusted. Further, the leveling unit 50 causes the Z position of the plate P to be in the just focus (coincides with the imaging point of the projection optical system PL) based on the detection result of the autofocus sensor and the detection result of the detection device 59. In addition, the plate table 19 can be moved in the Z direction, θX direction, and θY direction with respect to the Y movable element 20a (positioning in the Z position, θX direction, and θY direction is performed).

  Next, with reference to FIG. 4, the details of the control device 11 that drives and controls the linear motors 14 and 16 so that the plate stage PST and the mask stage MST move synchronously in the X-axis direction will be described. FIG. 4 is a block diagram illustrating a configuration of the control device 11 and a control target thereof.

  In FIG. 4, the control device 11 includes a first two-degree-of-freedom control system 100 and a second two-degree-of-freedom control system 200. The first two-degree-of-freedom control system 100 is a control system for driving and controlling the plate stage PST. The trajectory generation unit 101, the feedforward control unit 102, the feedback control unit 103, the state prediction unit 104, And adding units 105 and 106. The second two-degree-of-freedom control system 200 is a control system for driving and controlling the mask stage MST, and includes a feedforward control unit 202, a feedback control unit 203, and addition units 205 and 206. ing.

  In this embodiment, as will be described below, the first two degrees of freedom control system 100 serves as a master to drive and control the plate stage PST, and the second two degrees of freedom control system 200 serves as a slave as a mask stage. A master / slave system is configured to drive and control the MST in synchronization with the plate stage PST.

  First, the first two-degree-of-freedom control system 100 will be described.

  To the trajectory generator 101, the X coordinate of the movement start point and the X coordinate of the movement end point of the plate stage PST are input. The movement start point represents the current position on the X axis of the plate stage PST, and the movement end point represents the target position on the X axis to which the plate stage PST is moved. The trajectory generation unit 101 generates a target trajectory for moving the plate stage PST from the movement start point to the movement end point based on the input movement start point and movement end point. The target trajectory can be data obtained by sampling the position X (t) of the plate stage PST associated with each time t at a predetermined period Tr. Further, the trajectory generation unit 101 generates a target trajectory not only for position data but also for each data for all states of the controllable canonical system, such as speed and acceleration.

  The feedforward control unit 102 receives the above target trajectory related to all the states ahead by the time Tr corresponding to one sampling period in the trajectory generation unit 101 as an input, and performs complete follow-up control on the X coordinate position of the plate stage PST (for example, JP, A, 2001-325005 and the paper “Complete tracking method using multi-rate feedforward control” (see Hiroshi Fujimoto et al., Vol. 36, No. 9, pp 766-772, 2000) Feed forward control. Specifically, the feedforward control unit 102 holds (stores) an inverse system that shows a response opposite to the control model that reproduces the control characteristics of the control target 301 (plate stage PST) (the input and output are in an inverse relationship). By using this reverse system, a drive signal for driving the linear motor 16 is generated. This drive signal is an operation amount from the feedforward control unit 102 for the control target 301. It is assumed that the feedforward control unit 102 captures input at the above sampling period Tr and outputs the generated drive signal at a predetermined sampling period Tu.

  The addition result of the addition unit 106 is input to the feedback control unit 103. The addition result of the adding unit 106 is an X position of the plate stage PST (X position information obtained by the plate interferometer 25, that is, X expressed by the above-described formula X = (X1 + X2) / 2) and feedforward control. This is a difference from the output of the unit 102.

The feedback control unit 103 feedback-controls the X coordinate position of the plate stage PST based on the output of the adding unit 106, that is, the error of the X position of the plate stage PST with reference to the target trajectory. Specifically, the feedback control unit 103 generates a drive signal for driving the linear motor 16 so that the error becomes zero. This drive signal is an operation amount from the feedback control unit 103 to the control target 301.
The X position of the plate stage PST is read at a predetermined sampling period Ty, and the feedback control unit 103 takes in the input at a predetermined sampling period Ty and outputs the generated drive signal at a predetermined sampling period Tu. It shall be.

  The operation amount from the feedforward control unit 102 and the operation amount from the feedback control unit 103 are added by the addition unit 105, and the operation amount after the addition is given to the control object 301 (plate stage PST).

  The state prediction unit 104 predicts the state of the control target 301 ahead (including the position, speed, and acceleration of the plate stage PST) for a predetermined sampling time according to the input to the control target 301 and the output from the control target 301. To do. In this prediction, the control dead time of the first two-degree-of-freedom control system 100 and the second two-degree-of-freedom control system 200 (for example, the time required for the control calculation or the output after the input to the control target is obtained It is necessary to take into account the time required for (the stage position is observed). That is, the state predicting unit 104 in the future by the time corresponding to the dead time so that the operation amount synchronized with the input to the control target 301 (plate stage PST) is input to the control target 302 (mask stage MST). Make predictions. A specific example of the calculation method will be described later.

  Next, the second two-degree-of-freedom control system 200 will be described.

  The state of the control target 301 (plate stage PST) predicted by the state prediction unit 104 is input to the feedforward control unit 202. The feedforward control unit 202 uses the state of the input control target 301 (plate stage PST) as a target trajectory, as with the feedforward control unit 102 of the first two-degree-of-freedom control system 100 described above, X of the mask stage MST. The coordinate position is feedforward controlled based on complete tracking control. Specifically, the feedforward control unit 202 holds (stores) an inverse system that shows a response opposite to that of the control model that reproduces the control characteristics of the control target 302 (mask stage MST) (input and output are in an inverse relationship). By using this reverse system, a driving signal for driving the linear motor 14 is generated. This drive signal is an operation amount from the feedforward control unit 202 for the control target 302. Note that the feedforward control unit 202 captures input at the above-described sampling period Tr and outputs the generated drive signal at a predetermined sampling period Tu.

  The addition result of the addition unit 206 is input to the feedback control unit 203. The addition result of the adding unit 206 is a difference between the X position of the mask stage MST (X position information obtained by the mask interferometer 18) and the output of the feedforward control unit 202.

The feedback control unit 203 feedback-controls the X coordinate position of the mask stage MST based on the output of the adding unit 206, that is, the error of the X position of the mask stage MST with reference to the target trajectory. Specifically, the feedback control unit 203 generates a drive signal for driving the linear motor 14 so that the error becomes zero. This drive signal is an operation amount from the feedback control unit 203 to the control target 302.
Note that the X position of the mask stage MST is read at a predetermined sampling period Ty, and the feedback control unit 203 outputs the generated drive signal at a predetermined sampling period Tu.

  The operation amount from the feedforward control unit 202 and the operation amount from the feedback control unit 203 are added by the addition unit 205, and the operation amount after the addition is given to the control target 302 (mask stage MST).

  Next, an algorithm in which the state prediction unit 104 predicts the state of the control target 301 (plate stage PST) will be described.

It is assumed that the dead times generated in the control objects 301 and 302 and the arithmetic processing are T _dim and T _dis (subscript m is the master side, s is the slave side, and so on), and the input terminal has a delay. Further, the dead time of the sensor (interferometer) is assumed to be T _dom and T _dos and it is considered that there is a delay at the output end. Here, the master side state x _m (kT _y + T _dim ) can be estimated at time kT _y by collecting the dead time on the master side at the output end. Since the actual position _y s (t) the actual position _y m (t) master state needed to synchronize to the master side of the slave side is _{x m (kT y + n s} T u + T dis), estimated The state further advanced by n _{s Tu} + T _dis −T _dim from the state x _m (kT _y + T _dim ) becomes the slave target trajectory. Here, _ns is the order of the control target 302 on the slave side.

  The continuous time state equation of the control object 301 excluding the master side dead time is expressed by the following equation (1) by the controllable canonical realization, and the continuous time state equation of disturbance on the master side is expressed by the following equation (2).

  At this time, the extended system continuous-time equation of state can be expressed by the following equations (3) and (4).

The expanded system discrete-time state equation of period _{Tu in} equation (3) is defined as the following equation (5).

  Similarly, the subscript m is defined as s on the slave side.

  Here, the dead time collected at the output end on the master side is defined as in the following equation (6).

The state prediction unit 104 predicts the state x _m (kT _y + T _dim ) on the master side at time kTu as the state x _m [k]. The explanation will be divided into cases where there is no dead time and cases where there is no dead time as follows.

When there is no dead time (T _dm = 0), the state x _m [k] can be predicted using the following equations (7) and (8). This is a general observer.

When there is a dead time, if (n _dm −1) T _y <T _dm ≦ n _dm T _y (n _dm = 1, 2,...), The output signal y _m [k] that can be used at the time kT _y is It is given by the following equations (9), (10), (11).

Then, the state x _m [k] can be predicted using an algorithm based on the following equation (12). Expression (13) is an expression necessary for obtaining the observer gain H and represents the state transition of the estimation error.

Thus, since Motoma' state estimate of master _x m [k] at time kT _y, further predict _{n s} in the sample each at the same time _{n s T y + T dis -T} dim destination state _{x m [i + N + σ} ] To do. However, [i] = (i · n _s T _y ), N = 0, 1,..., 0 ≦ σ <1. Here, if n _s T _y + T _dis −T _dim <0, the predicted state x _m [k] may be delayed by this amount. On the other hand, when n _s T _y + T _dis −T _dim ≧ 0, the next state x _m [i + N + σ] is predicted from the predicted state x _m [k] using the following equations (14) to (19). . Here, u _om represents a nominal control input calculated in advance by the multi-rate feedforward controller.

  Next, a modification of the control device 11 will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of the control device 11 according to this modification and the control target thereof.

In FIG. 5, the control device 11 is different from FIG. 4 only in that a difference calculation unit 107 is provided instead of the state prediction unit 104.
The difference calculation unit 107 calculates the difference between these values according to the current value output from the control object 301 and the value before the predetermined sampling time from the present time, and the state of the control object 301 including the value related to the speed Is calculated. For example, the speed of the control target 301 can be obtained by dividing the difference between the current value output from the control target 301 and the value one sampling time earlier by the sampling time. As a speed calculation method using such a difference, for example, there is a method using a highly accurate center difference. In the calculation method using the difference, the calculated speed is delayed from the current value according to the sampling time (for example, one sample delay or half sample delay). Also, the difference calculation unit 107 calculates other state variables such as a value related to acceleration and a value related to jerk (jerk) as an amount representing the state of the control target 301 in addition to the speed by the same method. You can also. When obtaining these multiple values, each may be calculated individually from the difference, or may be calculated so that the sampling delay of the desired value is the same sampling point at each value.

In the case of the control device 11 having the configuration of FIG. 5 using the difference calculation unit 107, unlike the configuration using the state prediction unit 104 of FIG. 4, the state of the control target 301 cannot be predicted, and the control target 301 is moved to. Therefore, the operation amount synchronized with a delay of 2n _s −1 samples from the input is input to the control object 302. Therefore, it is not possible to perform strict synchronous control in consideration of the dead time as in the configuration of FIG. 4, but compared with the conventional control system in which the control on the slave side is performed only by feedback control based on the actual position on the master side, There is an advantage that a certain degree of effect that the slave side follows the master side is obtained, and that the difference calculation unit 107 has a simpler configuration than the state prediction unit 104.

  Next, another modification of the control device 11 will be described with reference to FIG. FIG. 6 is a block diagram showing the configuration of the control device 11 according to this modification and the control target.

  In the control device 11 of FIG. 6, the first two-degree-of-freedom control system 100 includes a trajectory generation unit 101, a feedforward control unit 102, a feedback control unit 103, and addition units 105 and 106. The second two-degree-of-freedom control system 200 includes a trajectory generation unit 201, a feedforward control unit 202, a feedback control unit 203, and addition units 205 and 206. Only differences from the control device 11 of FIG. 4 will be described below.

  The second two-degree-of-freedom control system 200 includes a trajectory generation unit 201 similar to that of the first two-degree-of-freedom control system 100. To this trajectory generation unit 201, the X coordinate of the movement start point of the mask stage MST and the X coordinate of the movement end point are input. The movement start point represents the current position of the mask stage MST on the X axis, and the movement end point represents the target position on the X axis to which the mask stage MST is moved. The trajectory generation unit 201 generates a target trajectory for moving the mask stage MST from the movement start point to the movement end point based on the input movement start point and movement end point. The target trajectory is time-series data of the position X (t) of the mask stage MST associated with each time t, and an appropriate algorithm can be used as the generation algorithm.

  The feedforward control unit 202 uses the target trajectory output from the trajectory generation unit 201 as an input, and feedforward controls the X coordinate position of the mask stage MST based on complete tracking control as in the case of FIG.

  The addition result of the addition unit 206 is input to the feedback control unit 203. The addition result of the adding unit 206 is an X position of the mask stage MST (X position information obtained by the mask interferometer 18) and an X position of the plate stage PST (X position information obtained by the plate interferometer 25). It is a difference. The feedback control unit 203 feedback-controls the X coordinate position of the mask stage MST based on the output of the addition unit 206, that is, the error of the X position of the mask stage MST with reference to the X position of the plate stage PST.

  The control device 11 having the configuration shown in FIG. 6 includes a feedforward control unit 202 that performs complete tracking control as compared with a conventional control system that performs control on the slave side only by feedback control based on the actual position on the master side. Therefore, if the controlled object is nominal, the two stages can be moved completely in synchronization.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

It is the schematic which shows the structure of the exposure apparatus which concerns on embodiment of this invention. It is sectional drawing which shows a part of structure of the exposure apparatus which concerns on this embodiment. It is sectional drawing which shows a part of structure of the exposure apparatus which concerns on this embodiment. It is a block diagram which shows the structure of the control apparatus which concerns on this embodiment. It is a block diagram which shows the structure of the control apparatus (modification) which concerns on this embodiment. It is a block diagram which shows the structure of the control apparatus (other modification) which concerns on this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Control apparatus 14, 16 ... Linear motor 100 ... 1st 2 degree-of-freedom control system 101 ... Trajectory generation part 102 ... Feedforward control part 103 ... Feedback control part 104 ... State prediction part 105, 106 ... Addition part 107 ... Difference Arithmetic unit 200: second two-degree-of-freedom control system 201 ... trajectory generating unit 202 ... feedforward control unit 203 ... feedback control unit 205, 206 ... addition unit 301 ... controlled object (plate stage PST) 302 ... controlled object (mask stage) MST)

Claims (7)

A stage device for driving the first stage and the second stage in synchronization with each other;
A first two-degree-of-freedom control means comprising a first feedforward control means and a first feedback control means for controlling the position of the first stage;
Second 2-degree-of-freedom control means comprising second feedforward control means and second feedback control means for controlling the position of the second stage;
With
The second two-degree-of-freedom control means performs control based on the position of the first stage,
The first and second feedforward control means perform complete tracking control.
Stage device. A state predicting means for predicting a state of the first stage including at least values relating to position and velocity;
The second feedforward control means controls the position of the second stage based on the state of the first stage predicted by the state prediction means;
The stage apparatus according to claim 1.   The stage apparatus according to claim 2, wherein the state predicting unit predicts the state of the first stage ahead by a dead time in the control by the first and second two-degree-of-freedom control units. Computation means for calculating at least a value relating to speed from the difference using the current and past positions of the first stage,
The second feedforward control means controls the position of the second stage based on the position of the first stage and at least a value related to the speed of the first stage calculated by the computing means;
The stage apparatus according to claim 1.   The stage apparatus according to claim 1, wherein the second feedback control unit feedback-controls the position of the second stage with reference to the position of the first stage. In an exposure apparatus that exposes a mask pattern held on a mask stage onto a photosensitive substrate held on a substrate stage,
The substrate stage is the first stage according to any one of claims 1 to 5, and the mask stage is the second stage according to any one of claims 1 to 5. Exposure apparatus. A first two-degree-of-freedom control means comprising a first feed-forward control means and a first feedback control means for controlling the position of the first stage; a second feed-forward control means and a second feedback for controlling the position of the second stage; A stage control method for a stage apparatus, comprising: a second two-degree-of-freedom control unit comprising a control unit, and driving the first stage and the second stage in synchronization with each other;
The second two-degree-of-freedom control means performs control based on the position of the first stage,
The first and second feedforward control means perform complete tracking control.
Stage control method.

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