Base support device and exposure device

Abstract

The purpose of the present invention is to provide a base support device capable of suppressing deformation of a base.　A base support device (810) comprises: a plurality of actuators (81b) that are disposed on an installation surface, each support a base (81a) at each of a plurality of support points on the lower surface side of the base (81a), and generate thrust in a support direction with respect to the support points; a plurality of detection units (82) that each detect a first position in the support direction of each of the plurality of support points with respect to the installation surface; and a control unit (CNT) that calculates an approximate plane of the lower surface of the base (81a) on the basis of the first position detected by each of the plurality of detection units (82), calculates a second position in the support direction with respect to the installation surface of each point where an axis passing through the support point and extending in the support direction and the approximate plane cross each other, and controls the plurality of actuators (81b) on the basis of the difference between the second position and the first position of each of the support points.

Description

Base support device and exposure device

[0001] The present invention relates to a base support device and an exposure apparatus.

[0002] For example, in the lithography process, which is one of the manufacturing processes for electronic devices (microdevices) such as semiconductor devices or liquid crystal display elements, a one-shot exposure (static exposure) exposure device such as a stepper or a scanning exposure type exposure device such as a scanning stepper is used to transfer and expose a pattern formed on a mask (reticle) onto a glass plate (or wafer) coated with photoresist.

[0003] In exposure apparatuses, a vibration isolation table is disposed between a base member (base plate) of the exposure apparatus and the floor (installation surface) in order to eliminate the effects of vibration and improve exposure accuracy such as the positioning accuracy and overlay accuracy of the mask stage and substrate stage. Anti-vibration devices have been proposed that actively control the vibration of the vibration isolation table by detecting the vibration of the vibration isolation table with a sensor and feeding back the detection signal to an actuator that applies a control force to the vibration isolation table (for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2001-304332

[0005] According to a first aspect of the disclosure, a base support device is arranged on an installation surface, supports the base at each of a plurality of support points on the underside of the base, and includes a plurality of actuators that generate thrust in a support direction relative to the support points; a plurality of detection units that detect first positions in the support direction of each of the plurality of support points relative to the installation surface; and a control unit that calculates an approximate plane of the underside of the base based on the first positions detected by each of the plurality of detection units, calculates second positions in the support direction relative to the installation surface for each of points where an axis that passes through the support points and extends in the support direction intersects with the approximate plane, and controls the thrust generated by each of the plurality of actuators based on the difference between the second position and the first position of each of the support points.

[0006] According to a second aspect of the disclosure, the exposure apparatus comprises the above-mentioned base support device, a mask stage that can move while holding a mask, and an optical surface plate that supports the mask stage and is arranged on the base support device.

[0007] According to a third aspect of the disclosure, the exposure apparatus includes the above-mentioned base support device, a stage positioned on the base support device, capable of holding a substrate and moving in a scanning direction, and a projection optical system positioned on the stage, and the control unit detects the first position when the stage is moved in the scanning direction relative to the projection optical system, calculates the approximate plane, calculates the second position, and controls the thrust generated by each of the plurality of actuators based on the difference between the second position and the first position of each of the support regions.

[0008] The configurations of the embodiments described below may be modified as appropriate, and at least a portion of the configuration may be replaced with other components. Furthermore, components that are not particularly limited in terms of their placement may be placed in any position that can achieve their function, not limited to the placement disclosed in the embodiments.

[0009] FIG. 1 is a diagram schematically illustrating the configuration of an exposure apparatus equipped with an anti-vibration device according to an embodiment. FIG. 2A is a plan view of the anti-vibration device as viewed from the +Z direction, and FIG. 2B is a view of the anti-vibration device as viewed from the -X direction. FIG. 3 is a diagram for explaining the configuration of the anti-vibration device. FIG. 4 is a block diagram illustrating an example of a body attitude control method. FIG. 5A is a diagram illustrating the simulation results of a Z position (first position) based on the floor surface of a support point, FIG. 5B is a diagram illustrating the calculation results of a Z position (second position) based on the floor surface of a support point in a least-squares plane calculated from the first position, and FIG. 5C is a diagram illustrating the difference between the first position and the second position for each support point. FIG. 6 is a diagram illustrating, in an XYZ Cartesian coordinate system, the relationship between the Z position (first position) based on the floor surface of a support point and the Z position (second position) based on the floor surface of a support point in a least-squares plane calculated from the first position. Fig. 7 is a block diagram showing the control method according to this embodiment. Fig. 8 is a graph showing the simulation results of the difference between the first position and the second position when the control method according to this embodiment is applied. Fig. 9(A) is a diagram showing the movement speed of the substrate stage versus time, Fig. 9(B) is a diagram showing the movement speed of the mask stage versus time, and Figs. 9(C) to 9(F) are diagrams comparing the difference between the first position and the second position at each support point calculated based on the output of the position sensor when control according to the comparative example is performed with the difference between the first position and the second position at each support point calculated based on the output of the position sensor when control according to this embodiment is performed.

[0010] An exposure apparatus 10 equipped with an anti-vibration device 81 according to one embodiment will be described with reference to FIGS.

[0011] (Configuration of Exposure Apparatus 10) FIG. 1 is a diagram that shows roughly the configuration of an exposure apparatus 10 that is equipped with an anti-vibration device 81 according to this embodiment.

[0012] The exposure apparatus 10 is a scanning stepper (scanner) that drives a mask MSK and a substrate (e.g., a glass substrate) P in the same direction and at the same speed relative to a projection optical system PL, thereby transferring a pattern formed on the mask MSK onto the substrate P. The substrate P is a rectangular glass substrate used in, for example, a liquid crystal display device (flat panel display), with at least one side or diagonal length of 500 mm or more.

[0013] In the following, the direction in which the mask MSK and substrate P are driven during scanning exposure (scanning direction) is referred to as the X-axis direction, the direction in a horizontal plane perpendicular to this is referred to as the Y-axis direction, the direction perpendicular to the X-axis and Y-axis is referred to as the Z-axis direction, and the directions of rotation (tilt) about the X-axis, Y-axis, and Z-axis are referred to as the θx direction, θy direction, and θz direction, respectively. Furthermore, positions in the X-axis direction, Y-axis direction, and Z-axis direction are referred to as the X position, Y position, and Z position, respectively. Furthermore, positions in the θx direction, θy direction, and θz direction are referred to as the θx position, θy position, and θz position, respectively.

[0014] The exposure apparatus 10 includes an illumination system IOP, a mask stage MST that holds a mask MSK, a projection optical system PL, a body 70 that supports these, a substrate stage PST that holds a substrate P, and a control device CNT for these components. The control device CNT controls all of the components of the exposure apparatus 10.

[0015] The body 70 includes a lower column (hereinafter referred to as a base) 81a, columns 72A and 72B, an optical surface plate 73, a support 74, a slide guide 75, and the like.

[0016] The base 81a is supported by a plurality of pneumatic mounts (actuators) 81b and passive mounts (not shown) arranged on the floor surface (installation surface) F. The plurality of pneumatic mounts 81b support the base 81a at a plurality of support points, and generate thrust in the support direction (Z-axis direction) relative to the support points. The passive mounts are, for example, air dampers that are controlled so that the internal pressure remains approximately constant. The base 81a and the plurality of pneumatic mounts 81b constitute the vibration isolation device 81.

[0017] Each of columns 72A and 72B has a frame shape, with column 72A being disposed inside column 72B. Optical surface plate 73 has, for example, a flat plate shape, and is fixed to the ceiling of column 72A. Support body 74 is supported on the ceiling of column 72B via slide guides 75. Slide guide 75 includes an air ball lifter and a positioning mechanism, and positions support body 74 (i.e., mask stage MST, described later) at an appropriate position in the X-axis direction relative to optical surface plate 73.

[0018] The illumination system IOP is disposed above the body 70. The illumination system IOP irradiates the mask MSK with illumination light IL.

[0019] The mask stage MST is supported by a support 74. A mask MSK having a pattern surface (the lower surface in FIG. 1 ) on which a circuit pattern is formed is fixed to the mask stage MST by, for example, vacuum suction (or electrostatic suction). The mask stage MST is driven by a drive system including, for example, a linear motor at a predetermined stroke in the scanning direction (X-axis direction), and is also driven slightly in the non-scanning directions (Y-axis direction and θz direction).

[0020] Position information of the mask stage MST in the XY plane (including rotation information in the θz direction) is measured by an interferometer system. The interferometer system measures the position of the mask stage MST by irradiating a measurement beam onto a movable mirror (or a mirror-finished reflective surface (not shown)) provided at the end of the mask stage MST and receiving the reflected light from the movable mirror. The measurement results are supplied to a control device CNT, which drives the mask stage MST via a drive system in accordance with the measurement results of the interferometer system.

[0021] The projection optical system PL is supported on an optical surface plate 73 below (on the -Z side of) the mask stage MST. The projection optical system PL is configured similarly to the projection optical system disclosed in, for example, U.S. Pat. No. 5,729,331. The projection optical system PL includes multiple (e.g., seven) projection optical units 100 (multi-lens projection optical units) arranged, for example, in a staggered pattern, to project the pattern image of the mask MSK. This forms a rectangular image field with the Y-axis direction as its longitudinal direction. Here, four projection optical units 100 are arranged at predetermined intervals in the Y-axis direction, and the remaining three projection optical units 100 are arranged at predetermined intervals in the Y-axis direction, spaced apart from the four projection optical units 100 on the +X side. Each of the multiple projection optical units 100 is, for example, a bilaterally telecentric, 1x1 system that forms an erect, normal image. The multiple projection areas of the staggered projection optical units 100 are collectively referred to as the exposure area.

[0022] When the illumination area on the mask MSK is illuminated by illumination light IL from the illumination system IOP, the illumination light IL that has passed through the mask MSK forms a projected image (partial erect image) of the circuit pattern of the mask MSK within that illumination area, via the projection optical system PL, in an irradiation area (exposure area (conjugate to the illumination area)) on the substrate P, which is arranged on the image plane side of the projection optical system PL. Here, a resist (sensitizer) is applied to the surface of the substrate P. By synchronously driving the mask stage MST and the substrate stage PST, i.e., by driving the mask MSK in the scanning direction (X-axis direction) relative to the illumination area (illumination light IL) and driving the substrate P in the same scanning direction relative to the exposure area (illumination light IL), the substrate P is exposed and the pattern of the mask MSK is transferred onto the substrate P.

[0023] The substrate stage PST is disposed below (on the −Z side of) the projection optical system PL on an anti-vibration device 81. The substrate P is held on the substrate stage PST via a substrate holder (not shown).

[0024] Position information of the substrate stage PST in the XY plane (including rotation information (yawing amount (rotation amount θz in the θz direction), pitching amount (rotation amount θx in the θx direction), and rolling amount (rotation amount θy in the θy direction))) is measured by an interferometer system. The interferometer system measures the position of the substrate stage PST by irradiating a measurement beam from the optical surface plate 73 onto a movable mirror (or a mirror-finished reflective surface (not shown)) provided at the end of the substrate stage PST, and receiving the reflected light from the movable mirror. The measurement results are supplied to the control device CNT, and the control device CNT drives the substrate stage PST in accordance with the measurement results of the interferometer system.

[0025] In the exposure apparatus 10, alignment measurement (for example, EGA, etc.) is performed prior to exposure, and the results are used to expose the substrate P in the following procedure. First, in accordance with instructions from the control device CNT, the mask stage MST and the substrate stage PST are synchronously driven in the X-axis direction. This performs scanning exposure on the first shot area on the substrate P. When scanning exposure on the first shot area is completed, the control device CNT moves (steps) the substrate stage PST to a position corresponding to the second shot area. Then, scanning exposure is performed on the second shot area. Similarly, the control device CNT repeats stepping between shot areas on the substrate P and scanning exposure on the shot areas to transfer the pattern of the mask MSK to all shot areas on the substrate P.

[0026] (Configuration of Anti-vibration Device 81) Next, the configuration of the anti-vibration device 81 will be described. Fig. 2(A) is a plan view of the anti-vibration device 81 as seen from the +Z direction, and Fig. 2(B) is a view of the anti-vibration device 81 as seen from the -X direction. Fig. 3 is a diagram for explaining the configuration of the anti-vibration device 81.

[0027] 1, the vibration isolation device 81 includes a base 81a and a base support device 810. The base support device 810 includes a plurality of pneumatic mounts 81b that support the base 81a, a plurality of position sensors 82-1, 82-2, 82-3, and 82-4, and a control device CNT. As shown in FIG. 2A, in this embodiment, the base 81a has a rectangular outer shape in a plan view, and the pneumatic mounts 81b include pneumatic mounts 81b-1, 81b-2, 81b-3, and 81b-4 provided at the four corners of the base 81a.

[0028] Each of the pneumatic mounts 81b-1 to 81b-4 has a bellows made of, for example, synthetic rubber, and one end of the bellows in the expansion / contraction direction (here, the Z-axis direction) is mechanically connected to the underside of the base 81a, and the other end is installed on the floor surface F. As shown in Figure 3, an air supply device 85 is connected to the bellows of the pneumatic mounts 81b-1 to 81b-4 via valves 83-1, 83-2, 83-3, and 83-4. By changing the opening of the valves 83-1 to 83-4, the pressure inside the bellows of the pneumatic mounts 81b-1 to 81b-4 can be changed, and the thrust in the Z-axis direction generated by the pneumatic mounts 81b-1 to 81b-4 can be changed.

[0029] In this embodiment, the pneumatic mounts 81b-1 to 81b-4 have a cylindrical shape with the Z-axis direction as their axis, and therefore the centers of the regions where one end of the bellows of each of the pneumatic mounts 81b-1 to 81b-4 contacts the underside of the base 81a are referred to as support points SP1, SP2, SP3, and SP4, respectively. The regions where one end of the bellows of each of the pneumatic mounts 81b-1 to 81b-4 contacts the underside of the base 81a may also be referred to as support points SP1 to SP4. Alternatively, points other than the centers of these regions may also be referred to as support points SP1 to SP4.

[0030] Position sensors 82-1, 82-2, 82-3, and 82-4 are provided at the support points SP1 to SP4 of the pneumatic mounts 81b-1 to 81b-4, respectively, to detect the Z-axis position (sometimes referred to as the Z relative position) of each of the support points SP1 to SP4 relative to the floor surface F.

[0031] 3, the position detection signals output by the position sensors 82-1 to 82-4 are input to the control device CNT. The control device CNT also receives pressure detection signals output by pressure sensors 84-1, 84-2, 84-3, and 84-4 that measure the pressures in the bellows of the pneumatic mounts 81b-1 to 81b-4, respectively.

[0032] The control device CNT controls the openings of the valves 83-1, 83-2, 83-3, and 83-4 based on position detection signals from the position sensors 82-1 to 82-4 and pressure detection signals from the pressure sensors 84-1 to 84-4, and controls the thrust in the Z-axis direction generated by the pneumatic mounts 81b-1 to 81b-4, thereby controlling the attitude of the base 81a, i.e., the attitude of the body 70.

[0033] In the exposure apparatus 10, the posture of the body 70 changes due to vibrations transmitted from the floor F, etc., as well as due to load movements that accompany movement of the substrate stage PST and mask stage MST in the scanning direction. For this reason, exposure apparatuses typically perform posture control to bring the posture of the body 70 closer to a target posture. The posture control is performed, for example, when the substrate stage PST is being moved in the scanning direction relative to the projection optical system PL.

[0034] Fig. 4 is a block diagram showing an example of a method for controlling the attitude of the body 70. In the attitude control method shown in Fig. 4, the body 70 of the exposure apparatus 10 is regarded as a rigid body.

[0035] 4, a signal corresponding to the target attitude of the body 70 of the exposure apparatus 10 is supplied to the addition side of the subtraction unit 200. In addition, signals corresponding to the Z relative positions measured by the position sensors 82-1 to 82-4 are supplied to the subtraction side of the subtraction unit 200 after being coordinate-converted into the Z position, θx position (rotation about the X axis), and θy position (rotation about the Y axis) of the body 70. The Z position, θx position (rotation about the X axis), and θy position (rotation about the Y axis) of the body 70 are also supplied to a feedback (FB) control unit 202.

[0036] The output of the subtraction unit 200 is supplied to a PI control unit 201 for performing proportional control and integral control. The output of the PI control unit 201 and the output of the FB control unit 202 are supplied to an addition unit 203.

[0037] The output from the adder 203 (command values ​​for the Z position, θx position (rotation around the X axis), and θy position (rotation around the Y axis) of the body 70) is converted into pressures (target pressures) for the four pneumatic mounts 81b-1 to 81b-4 to achieve the command values, and is supplied to the adder 206. In addition, the output (pressure value) from a feedforward (FF) control unit 205 based on the positions of the substrate stage PST and mask stage MST is supplied to the adder 206.

[0038] The output from the adder 206 and the disturbance force are supplied to an adder 207, which calculates a pressure command value for each of the four pneumatic mounts 81b-1 to 81b-4. The control device CNT adjusts the opening of each of the valves 83-1 to 83-4 so that the pressures in the pneumatic mounts 81b-1 to 81b-4 become the pressure command values.

[0039] The inventors discovered that when controlling the attitude of the body 70 shown in Figure 4, deformation occurs in the base 81a (body 70) due to the movement of the load that accompanies the movement of the substrate stage PST and mask stage MST in the scanning direction.

[0040] Fig. 5(A) is a diagram showing the simulation results of the positions of support points SP1 to SP4 in the Z-axis direction relative to floor surface F (called first positions) when the pressure of pneumatic mounts 81b-1 to 81b-4 is controlled by the control method shown in Fig. 4. Fig. 5(B) is a diagram showing the results of calculating the least-squares plane of the underside of base 81a (the underside of body 70) based on the first positions of each of support points SP1 to SP4, and calculating the positions of the Z-axis direction (called second positions) relative to floor surface F (installation surface) of each of the points where the least-squares plane intersects with an axis that passes through each of support points SP1 to SP4 and extends in the Z-axis direction. The Z-axis direction positions of the points where an axis passing through each of the support points SP1 to SP4 and extending in the Z-axis direction intersects with the least squares plane, and which are based on the floor surface F (installation surface), can also be said to be the Z-axis direction positions of the calculated points based on the floor surface F when the points obtained by projecting the support points SP1 to SP4 onto the least squares plane in the Z-axis direction are calculated.

[0041] 5(C) is a diagram showing the difference between the first position and the second position at each of support points SP1 to SP4. The horizontal axis in FIGS. 5(A) to 5(C) represents time. Note that, since support point SP1 and support point SP4 exhibit almost identical behavior with respect to the first position, in FIG. 5(A), the first positions of support point SP1 and support point SP4 are represented by a single solid line (SP1,4), and since support point SP2 and support point SP3 exhibit almost identical behavior, the first positions of support point SP2 and support point SP3 are represented by a single dotted line (SP2,3). Furthermore, with respect to the second position, the support points SP1 and SP4 exhibit substantially the same behavior, so in Fig. 5(B) the second positions of the support points SP1 and SP4 are represented by a single solid line (SP1,4), and the support points SP2 and SP3 exhibit substantially the same behavior, so the second positions of the support points SP2 and SP3 are represented by a single dotted line (SP2,3). Furthermore, with respect to the difference between the first position and the second position, the support points SP2 and SP4 exhibit substantially the same behavior, so in Fig. 5(C) the difference between the first position and the second position is represented by a single solid line (SP2,4), and the support points SP1 and SP3 exhibit substantially the same behavior, so the difference between the first position and the second position is represented by a single dotted line (SP1,3).

[0042] As shown in Figure 5(C), there is a difference between the Z relative positions (first positions) of the support points SP1 to SP4 and the Z relative positions (second positions) of the support points SP1 to SP4 on the least squares plane. This means that deformation has occurred in the base 81a (i.e., the body 70). This point will be explained below.

[0043] 6 is a diagram showing, in an XYZ Cartesian coordinate system, the relationship between the Z relative positions (first positions) of the support points SP1 to SP4 and the Z relative positions (second positions) of the support points SP1 to SP4 on a least-squares plane calculated from the Z relative positions of the support points SP1 to SP4. The Z relative positions of the support points SP1 to SP4 are represented by coordinates (X1, Y1, Za1), (X2, Y2, Za2), (X3, Y3, Za3), and (X4, Y4, Za4), respectively. Meanwhile, the points on the least-squares plane corresponding to the support points SP1 to SP4 are respectively designated SP1' to SP4', and the positions of SP1' to SP4' are respectively represented by coordinates (X1, Y1, Zls1), (X2, Y2, Zls2), (X3, Y3, Zls3), and (X4, Y4, Zls4).

[0044] 5C, Za1>Zls1, Za3>Zls3, Za2<Zls2, and Za4<Zls4. This shows that the lower surface of base 81a, i.e., body 70, is deformed with respect to least-squares plane LSP indicated by the dotted line, as shown in FIG. 6. Deformation of body 70 may deteriorate the exposure accuracy of exposure apparatus 10.

[0045] Therefore, in this embodiment, the control loop shown in FIG. 4 is used as the main loop (second control), and a minor loop (first control) that suppresses deformation of the base 81 a is inserted, and a control method shown in the block diagram in FIG. 7 is adopted.

[0046] The block diagram shown in FIG. 7 differs from the block diagram shown in FIG. 4 in the portion enclosed by the dashed dotted line, and this point will be mainly described.

[0047] In the block diagram shown in Figure 7, the Z-axis positions (second positions) of each of the support points SP1 to SP4 in the least squares plane, calculated from the Z relative positions (first positions) of the support points SP1 to SP4 detected by the position sensors 82-1 to 82-4, relative to the floor surface F, are supplied to the subtraction side of the subtraction unit 208, and the Z relative positions (first positions) of the support points SP1 to SP4 detected by the position sensors 82-1 to 82-4 are supplied to the addition side.

[0048] The pressure of the pneumatic mounts 81b-1 to 81b-4 is controlled based on the difference (correction value) between the first position and the second position of each of the support points SP1 to SP4. Specifically, the pressure of the pneumatic mounts 81b-1 to 81b-4 is controlled so that the Z relative positions (first positions) of the support points SP1 to SP4 detected by the position sensors 82-1 to 82-4 coincide with the Z-axis positions (second positions) of the support points SP1 to SP4 on the least-squares plane relative to the floor surface F. This suppresses deformation of the base 81a (body 70).

[0049] The correction value used to control the pneumatic mounts 81b-1 to 81b-4 is supplied to the subtraction side of the subtraction unit 210, and the output from the addition unit 206 is supplied to the addition side, and pressure command values ​​for each of the four pneumatic mounts 81b-1 to 81b-4 in the main loop are calculated.

[0050] The minor loop is executed at a cycle that is the same as or shorter than that of the main loop, depending on the deformation time constant of the base 81a (body 70). Therefore, it is possible to perform attitude control of the body 70 while reducing the amount of deformation of the base 81a (body 70). In other words, the control method shown in FIG. 7 can suppress deformation of the base 81a (body 70) by the minor loop while maintaining attitude controllability of the body 70. This can improve the exposure accuracy of the exposure apparatus 10. Note that in this embodiment, the control target of the minor loop is static deformation of the base 81a (body 70), so the minor loop may be executed at a cycle that is longer than that of the main loop.

[0051] Fig. 8 is a graph showing the results of a simulation of the difference between the first position and the second position when the control method shown in Fig. 7 is applied. It can be seen that the difference between the first position and the second position is smaller than in Fig. 5(C). In other words, it was confirmed that the control method shown in Fig. 7 can reduce the amount of deformation of the body 70 while maintaining the attitude controllability of the body 70.

[0052] In the exposure apparatus 10 having the configuration shown in FIG. 1, the difference between the first position and the second position (position difference) at each of the support points SP1 to SP4 calculated based on the output of the position sensors 82-1 to 82-4 when control was performed in accordance with the block diagram shown in FIG. 4 (control related to the comparative example) was compared with the difference between the first position and the second position (position difference) at each of the support points SP1 to SP4 calculated based on the output of the position sensors 82-1 to 82-4 when control was performed in accordance with the block diagram shown in FIG. 7 (control related to the present embodiment).

[0053] Figure 9(A) is a diagram showing the movement speed of the substrate stage PST over time, where a positive movement speed indicates that the substrate stage PST has moved in the +X direction, and a negative movement speed indicates that the substrate stage PST has moved in the -X direction.

[0054] Figure 9(B) is a diagram showing the movement speed of the mask stage MST over time, where a positive movement speed indicates that the mask stage MST has moved in the +X direction, and a negative movement speed indicates that the mask stage MST has moved in the -X direction.

[0055] Figures 9(C) to 9(F) are diagrams comparing the difference (position difference) between the first position and the second position at each support point SP1 to SP4 calculated based on the output of position sensors 82-1 to 82-4 when control is performed in accordance with the block diagram shown in Figure 4 (control related to the comparative example), and the difference (position difference) between the first position and the second position at each support point SP1 to SP4 calculated based on the output of position sensors 82-1 to 82-4 when control is performed in accordance with the block diagram shown in Figure 7 (control related to this embodiment).

[0056] 9(C) to 9(F), it can be seen that when the control according to the embodiment is performed, the position difference is smaller at all support points SP1 to SP4 over the entire time period than when the control according to the comparative example is performed. In this way, it was confirmed not only by simulation but also in an actual exposure apparatus that the control according to the embodiment can suppress deformation of the base 81a (body 70).

[0057] As described above in detail, the base support device 810 according to this embodiment is disposed on the floor surface F, supports the base 81a at each of a plurality of support points SP1 to SP4 on the underside of the base 81a, and includes a plurality of pneumatic mounts 81b-1 to 81b-4 that generate thrust in the support direction (Z-axis direction) relative to the support points SP1 to SP4, and a plurality of position sensors 82-1 to 82-4 that detect the positions (first positions) of each of the plurality of support points SP1 to SP4 in the Z-axis direction relative to the floor surface F. The base support device 810 also includes a control device CNT that calculates a least-squares plane of the underside of the base 81a based on the first positions detected by each of the multiple position sensors 82-1 to 82-4, calculates positions in the Z-axis direction (second positions) based on the floor surface F of each of the points where the least-squares plane intersects with an axis that passes through the support points SP1 to SP4 and extends in the Z-axis direction, and controls the multiple pneumatic mounts 81b-1 to 81b-4 based on the difference between the second positions and the first positions of each of the support points SP1 to SP4.

[0058] 8 and 9(C) to 9(F), deformation of the base 81a can be suppressed. Furthermore, in this embodiment, the positions in the Z-axis direction of each of the support points SP1 to SP4 relative to the floor surface F (Z relative positions) are detected, and the least-squares plane is calculated using the Z relative positions, so that even if the floor surface F is uneven or tilted, for example, deformation of the lower surface of the base 81a relative to the floor surface F can be suppressed and the flatness can be maintained.

[0059] Furthermore, in this embodiment, the base 81a has a rectangular outer shape, and the pneumatic mounts 81b-1 to 81b-4 are provided near the four corners of the base 81a. When the base 81a is supported at three points, the degree of freedom of movement and the degree of freedom of control of the base 81a match, making deformation of the base 81a unlikely to occur. However, as the exposure apparatus 10 has become larger, the base 81a has also become larger, making it difficult to support the base 81a at three points. By supporting the base 81a at four points, even a large base 81a can be stably supported. On the other hand, when the base 81a is supported at four points, the degree of freedom of control exceeds the degree of freedom of movement of the base 81a, which may result in deformation of the base 81a (body 70). Therefore, as shown in this embodiment, by controlling the thrust generated by each of the multiple pneumatic mounts 81b-1 to 81b-4 based on the difference between the position (first position) of each of the support points SP1 to SP4 in the Z axis direction relative to the floor surface F and the position (second position) of each of the support points SP1 to SP4 in the Z axis direction relative to the floor surface F in a least-squares plane of the underside of the base 81a calculated based on the first position, it is possible to suppress deformation of the base 81a even when the base 81a is supported at four points. Note that the control method according to this embodiment is not limited to cases where the number of support points on the base 81a is four, and can also be applied to cases where there are five or more support points.

[0060] In this embodiment, the control device CNT controls the thrust generated in the Z-axis direction by each of the pneumatic mounts 81b-1 to 81b-4 on the support points SP1 to SP4 so that the difference between the second position and the first position of each of the support points SP1 to SP4 becomes small, thereby suppressing deformation of the base 81a.

[0061] In this embodiment, the control device CNT controls the thrust generated by each of the pneumatic mounts 81b-1 to 81b-4 based on the target attitude of the base 81a and the positions (first positions) of the support points SP1 to SP4 in the Z-axis direction detected by the position sensors 82-1 to 82-4, thereby making it possible to bring the attitude of the base 81a closer to the target attitude.

[0062] Furthermore, in this embodiment, the period (first period) during which the thrust generated by each of the plurality of pneumatic mounts 81b-1 to 81b-4 is controlled based on the difference between the second position and the first position of each of the support points SP1 to SP4 (the minor loop in FIG. 7) is the same as the period (second period) during which the thrust generated by each of the plurality of pneumatic mounts 81b-1 to 81b-4 is controlled based on the target attitude and the first position of the base 81a (the main loop in FIG. 7), or is shorter than the period during which the main loop is executed. This makes it possible to control the attitude of the base 81a (body 70) while suppressing deformation of the base 81a (body 70).

[0063] In the above embodiment, the pneumatic mounts 81b are used as the actuators, but actuators other than pneumatic mounts may be used. Also, dampers other than air dampers may be used as passive mounts.

[0064] In the above embodiment, the least-squares plane of the lower surface of the base 81a is calculated, but an approximation plane other than the least-squares plane may be calculated. For example, an approximation plane that minimizes the sum of the distances in the Z-axis direction from all measurement points may be calculated.

[0065] In the above embodiment, the Z relative positions of the support points SP1 to SP4 are converted into the Z position, θx position, and θy position of the base 81a, but they may also be converted into the Z position, θx position, θy position, and torsion component.

[0066] Furthermore, in the above embodiment, the exposure apparatus 10 is described as being a scanning stepper, but this is not limited to this, and the exposure apparatus 10 may be a stationary exposure apparatus such as a stepper, or may be a step-and-stitch type reduction projection exposure apparatus that combines shot areas.

[0067] Furthermore, in the above embodiment, the vibration isolation device 81 can also be applied to devices other than the exposure device 10 .

[0068] The above-described embodiment is a preferred example of the present invention, but the present invention is not limited to this and can be modified in various ways without departing from the spirit of the present invention.

[0069] 10 Exposure device 70 Body 81 Anti-vibration device 81a Base 81b, 81b-1 to 81b-4 Pneumatic mounts 82-1 to 82-4 Position sensors 73 Optical surface plate CNT Control device F Floor surface LSP Least squares plane MST Mask stage PST Substrate stage SP1 to SP4 Support points

Claims

1. A base support device comprising: a plurality of actuators arranged on an installation surface, supporting the base at each of a plurality of support points on the underside of the base and generating a thrust in a support direction relative to the support points; a plurality of detection units detecting a first position in the support direction of each of the plurality of support points based on the installation surface; and a control unit calculating an approximation plane of the underside of the base based on the first position detected by each of the plurality of detection units, calculating a second position in the support direction based on the installation surface for each of points where the approximation plane intersects with an axis that passes through the support points and extends in the support direction, and controlling the plurality of actuators based on a difference between the second position and the first position of each of the support points.

2. The base support device according to claim 1, wherein the base has a rectangular outer shape, and the actuators are provided near the four corners of the base.

3. The base support device according to claim 2, wherein the control unit controls the thrust generated by each of the plurality of actuators in the support direction relative to the support point so as to reduce the difference.

4. The base support device according to any one of claims 1 to 3, wherein the plurality of actuators are pneumatic actuators.

5. The base support device according to claim 3, wherein the control unit controls the thrust generated by each of the plurality of actuators based on a target attitude of the base and the first position detected by the detection unit.

6. A base support device as described in claim 5, wherein a first period during which control of the thrust generated by each of the plurality of actuators based on the difference is performed is substantially the same as or shorter than a second period during which control of the thrust generated by each of the plurality of actuators based on the target attitude and the first position is performed.

7. The base support device of claim 1, wherein the approximation plane is a least-squares plane.

8. An exposure apparatus comprising: a base support device according to any one of claims 1 to 7; a mask stage capable of holding a mask and moving; and an optical base supporting the mask stage and disposed on the base support device.

9. An exposure apparatus comprising: a base support device as defined in any one of claims 1 to 7; a stage positioned on said base support device, capable of holding a substrate and moving in a scanning direction; and a projection optical system positioned on said stage, wherein said control unit detects the first position while the stage is being moved in the scanning direction relative to the projection optical system, calculates the approximate plane, calculates the second position, and controls the thrust generated by each of said plurality of actuators based on the difference between the second position and the first position of each of said support points.

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