JP3797670B2 - Static pressure stage and scanning exposure apparatus - Google Patents

Description

The present invention relates to a static pressure stage using a magnet that lifts and supports a moving stage with respect to a surface plate with static pressure and attracts the moving stage toward the surface plate in order to increase its supporting rigidity, and more particularly to scanning. The present invention relates to a static pressure stage and a scanning exposure apparatus suitable for use in a type exposure apparatus.

As a conventional exposure apparatus, a so-called stepper is known in which a substrate to be exposed such as a wafer is sequentially moved and stopped to repeat exposure.

FIG. 11 shows details of the wafer stage of the stepper, and FIG. 12 shows an exploded view of the wafer stage. In the figure, a Y yaw guide 2 is fixed on a base surface plate 1, and a Y stage 3 guided by the side surface of the Y yaw guide 2 and the upper surface of the base surface plate 1 is an air slide (not shown) on the base surface plate 1 in the Y direction. It is slidably supported by. The Y stage 3 is mainly composed of four members, ie, two X yaw guides 3a and a large Y slider 3b and a small Y slider 3c. The large Y slider 3b is connected to the Y stage 3 via air pads (not shown) provided on the side and lower surfaces thereof. The side surface of the yaw guide 2 and the upper surface of the base surface plate 1 face each other, and the small Y slider 3c faces the upper surface of the base surface plate 1 through an air pad (not shown) provided on the side surface. As a result, the Y stage 3 as a whole is slidably supported in the Y direction on the side surface of the Y yaw guide 2 and the upper surface of the base surface plate 1 as described above.

On the other hand, an X stage 4 guided by the side surfaces of two X yaw guides 3a that are components of the Y stage 3 and the upper surface of the base surface plate 1 is provided so as to surround the Y stage 3 around the X axis. Are slidably supported by an air slide (not shown). The X stage 4 is mainly composed of four members, that is, two X stage side plates 4a, an upper and lower X stage top plate 4b, and an X stage bottom plate 4c. The X stage bottom plate 4c is interposed via an air pad 4d provided on the lower surface thereof. The two X stage side plates 4a face the upper surface of the base surface plate 1 and face the side surfaces of the two X yaw guides 3a, which are constituent members of the Y stage 3, through air pads (not shown) provided on the side surfaces. The lower surface of the X stage top plate 4b and the upper surface of the X yaw guide 3a, and the upper surface of the X stage bottom plate 4c and the lower surface of the X yaw guide 3a are not in contact with each other. As a result, the X stage 4 as a whole is slidably supported in the X direction on the side surfaces of the two X yaw guides 3a and the upper surface of the base surface plate 1 as described above. A workpiece holding mechanism (not shown) is provided on the top of the X stage top plate 4b so as to hold a workpiece such as a wafer. A not-shown square mirror is provided here, and the X and Y stages 4, 3 are provided. The position of can be measured accurately with a laser interferometer.

As the driving mechanism, one multi-phase coil switching type linear motor is used for X driving and two for Y driving. The stators 6a and 7a are obtained by inserting a plurality of coils 6c and 7c arranged in the stroke direction into a frame, and the movers 6b and 7b are constituted by box-shaped magnet units. 7d is a magnet coupling plate, and 8 is a Y stator fixing member. Thrust is generated by selectively passing a current through the coils 6c and 7c of the stators 6a and 7a according to the positions of the movers 6b and 7b.

In order to increase the rigidity of the air slide, it is necessary to keep the gap at about 5 μm. For this reason, as shown in the exploded view, the X stage 4 is attached to the base surface plate 1 by two preloading magnets 4e provided between the air pads 4d. It comes to be sucked. Y stage 3 as well is sucked Similarly, in not shown preload magnet in the Y slider atmospheric 3b side to the Y yaw guides 2, suction to the base plate 1 by unshown preload magnet in the Y slider atmospheric 3b underside and Y sliders small 3c underside It has come to be.

As these preload magnets, a plurality of rectangular magnet pieces 9 as shown in FIG. 13 are used. The base surface plate 1 and the Y yaw guide 2 are hardened and polished in SKS because they need to be attracted by magnets and the guide surface of the air slide.

By the way, it is desirable that the preload magnet provided to hold the air gap should only exert an attractive force in the direction opposite to the buoyancy direction of the air slide, but in reality, a resistance force in the sliding direction of the air slide is also generated. There is a problem of doing.

As a feature of the current stage configuration, the tilt posture of the X stage 4 is directly guided by the base surface plate 1. Therefore, the X stage 4 moves two-dimensionally while facing the base surface plate 1, and receives the resistance of the preload magnet 4e in both XY directions. The Y stage 3 receives the resistance of the preload magnet only in the Y direction.

On the other hand, as the preload magnet, a configuration in which a plurality of rectangular magnet pieces 9 as shown in FIG. 13 are arranged one-dimensionally is used. FIG. 2 shows the relationship between the thrust force and displacement of such a preload magnet. The first characteristic of the thrust force of the preload magnet is that when the relative speed between the surface plate and the stage is small, the thrust force changes with the displacement, and when the relative speed is large and the direction does not change, that is, when the displacement is large, the displacement is changed. It becomes almost constant regardless. That is, when the relative speed with the surface plate is small, the preload magnet acts as a spring for the surface plate and transmits the floor vibration to the stage. When the relative speed is high, it does not act as a spring and hardly transmits floor vibration.

As a second feature of the thrust force of the preload magnet, there is a remarkable anisotropy between the direction along which the magnet pieces 9 are arranged (the short side direction of the magnet pieces 9) and the direction perpendicular to the magnet piece 9 (the long side direction). Show.

Since the stepper is exposed in a stopped state, the relative speed between the preload magnet provided on the stage and the surface plate is always small, and the preload magnet acts as a spring for the surface plate, transmitting floor vibrations to the stage and causing a servo disturbance. It was. In other words, the region where the stepper does not act as a spring could not be used. Further, since the stepper is required to have the same stop accuracy in both the X direction and the Y direction, the optimum disturbance reduction using anisotropy cannot be performed.

Next, FIG. 14 shows an overall view of a scanning exposure apparatus, which is one of the next generation exposure apparatuses. In FIG. 14, the surface plate 1 is supported from a floor (or ground) 30 through vibration isolation means 31. On the surface plate 1, a wafer stage 33 that is movable in the XY plane is provided, and a reduction projection optical system 35 is fixed via a lens barrel support member 34. A reticle stage base 36 is provided above the support member 34, and a reticle stage 37 that can scan the reticle stage base 36 along the guide in one axial direction is provided. Illumination system 38 for applying exposure energy to the wafer through the reticle is shown in broken lines. 41 is an outer cylinder of the optical system 35, and 42 and 43 are interferometer standards.

In this apparatus, only a rectangular partial area of the reticle pattern is illuminated. Therefore, in order to expose the whole, the wafer stage 33 and the reticle stage 37 are synchronously scanned at a speed ratio equal to the reduction magnification of the optical system 35 and exposed during scanning. The wafer stage 33 is an XY stage. During exposure, the wafer stage 33 is controlled so that an axis parallel to the axis of the reticle stage 37 is scanned and the other axis is stationary.

There is also a system shown in FIG. 15 as an improved type. The projection optical system 35 supported by the lens barrel surface plate 45 is mechanically separated from the wafer stage surface plate 46 and directly supported by the vibration isolation means 31 from the floor 30. For this reason, the projection optical system 35 and the interferometer reference have an advantage that the vibration from the wafer stage 33 is not transmitted and the mechanical deformation and vibration of the optical system 35 and the interferometer references 42 and 43 can be extremely reduced. Further, the wafer stage surface plate 46 is directly supported from the floor 30 without the vibration isolation means 31 interposed therebetween. For this reason, there is an advantage that the swinging back of the surface plate 46 due to the reaction force when the wafer stage 33 is accelerated / decelerated is extremely small and the stopping accuracy is improved and the establishment time is shortened.

In such a system, the running resistance unevenness and the absolute value generated during scanning become new problems in the scanning direction. In the scanning exposure apparatus, since exposure is performed during scanning, if the running resistance during scanning is uneven, a thrust disturbance different from floor vibration acts on the stage to reduce the overlay accuracy in the scanning direction of scanning exposure.

The running resistance unevenness is the result of the resistance itself due to the magnetic hysteresis when the magnet and the platen are relatively displaced, and the combination with the drive system even if the magnetic hysteresis resistance unevenness is zero. It can be broadly divided into those that occur.

First, regarding the unevenness of the magnetic hysteresis resistance itself, in FIG. 7, the resistance unevenness when the magnet and the surface plate are relatively displaced is illustrated as zero, but there is actually some unevenness. The problem is the amount of the material which can be regarded as zero as shown in FIG. 7 depending on the surface plate material, and the material which is so uneven that the exposure accuracy is lowered. For example, in FIG. 2, when the platen material is SKS, the resistance unevenness when the magnet and the platen are relatively displaced can be regarded as zero, but when the platen material is Ni-based casting, the arrangement of rectangular magnet pieces constituting the magnet When scanning is performed in the direction along the short side of the rectangular magnet piece, noticeable unevenness synchronized with the magnetic pole pitch occurs.

Next, unevenness due to the combination with the drive system occurs when a linear motor of a type that switches a plurality of coils is used for the drive system. In this type of motor, the thrust constant changes periodically depending on the position. Therefore, when driving at a constant current, even if the resistance from the magnet is constant, the periodic unevenness of the thrust constant acts as the resistance unevenness as it is, and the exposure accuracy in the scanning direction is lowered. Since the magnitude of this unevenness is proportional to the absolute value of the resistance generated by the magnet, it is necessary to reduce the absolute value of the resistance of the magnet in order to reduce this.

Further, if the absolute value of the running resistance is large, extra thrust is required to overcome this, and the heat generation of the drive system increases or the cooling system for removing the heat generation becomes large.

On the other hand, in the direction of rest during scanning (hereinafter referred to as the step direction), the situation is exactly the same as that of the stepper, and the preload magnet resistance plays a role of transmitting the horizontal component of floor vibration. Normally, the wafer stage surface plate is supported by vibration isolation means as in the system of FIG. 14 to make it difficult to transmit floor vibration, but the residual is transmitted to the stage via a preload magnet. This lowers the servo performance and causes a reduction in image performance in a direction perpendicular to the scan, that is, a reduction in the contrast of the exposure pattern. In order to prevent this, the floor vibration level itself must be further reduced, which increases the total cost. In the system that directly supports the wafer stage surface plate from the floor as shown in FIG. 15, the floor vibration is transmitted to various places, which is a more serious problem.

The difference from the stepper is that the concept of the scanning direction and the non-scanning direction (step direction) has appeared in the scanning exposure apparatus, so that the anisotropy of the spring property of the magnet could be used.

The present invention has been made in view of the above-described problems in the conventional example, and an object of the present invention is to provide a static pressure stage and a scanning exposure apparatus in which the preload magnet has a small thrust resistance.
It is another object of the present invention to provide a static pressure stage and a scanning exposure apparatus with little thrust disturbance caused by a preload magnet.

In order to achieve the above object, the present invention provides a first stage movable on a surface plate in a first direction along a first guide provided on the surface plate, and the first stage. A second stage movable along a second guide provided on the surface plate in a second direction intersecting the first direction; and the first stage provided on the first stage and the second stage. First and second hydrostatic pressure applying means for levitating the second stage and the second stage, respectively, and the first and second stages provided on the first and second stages, respectively. In a static pressure stage used in a scanning exposure apparatus including first and second preload magnets that attracts toward a board, the surface plate is a low-carbon iron-based material, and the first and second preloads Magnets are one-dimensional by touching the sides of each rectangular magnet piece Is obtained by sequence, the second one-dimensional magnets and along the direction of the magnet pieces constituting the preloading magnets are static pressure stage, characterized in that perpendicular to the step direction.

Further, the present invention is arranged as a wafer stage in a scanning exposure apparatus in which the first direction and the second direction are orthogonal to each other, and one of these directions is a scanning direction and the other is a step direction. This is a static pressure stage described above.
Furthermore, in the present invention, the first direction is a scan direction, and the scan direction is orthogonal to a direction along a one-dimensional magnet of the magnet piece constituting the first preload magnet. The static pressure stage.

Furthermore, the present invention is characterized in that the second direction is a scanning direction, and the scanning direction is orthogonal to the one-dimensional magnets along the one-dimensional magnets constituting the first preload magnet. The static pressure stage.
Further, the present invention is characterized in that the surface plate is installed on a floor via vibration isolation means, and a projection optical system and a reticle stage constituting the scanning exposure apparatus are mounted on the surface plate. The above-described static pressure stage.

Further, according to the present invention, the surface plate is directly connected to the floor without the vibration isolation means, and the projection optical system and the reticle stage constituting the scanning exposure apparatus are installed on the floor via the vibration isolation means. The static pressure stage described above, which is mounted on a surface plate.
Furthermore, the present invention is the above-described static pressure stage, wherein the fluid for generating the static pressure is air.

Further, the scanning exposure apparatus of the present invention includes a first stage that is movable in a first direction on the surface plate along a first guide provided on the surface plate, and on the first stage. A second stage movable along a second guide provided on the surface plate in a second direction intersecting the first direction; and the first stage provided on the first stage and the second stage. First and second hydrostatic pressure applying means for levitating the second stage and the second stage, respectively, and the first and second stages provided on the first and second stages, respectively. In a static pressure stage used in a scanning exposure apparatus including first and second preload magnets that attracts toward a board, the surface plate is a low-carbon iron-based material, and the first and second preloads Magnets are one-dimensional by touching the sides of each rectangular magnet piece Is obtained by sequence, the second one-dimensional magnets and along the direction of the magnet pieces constituting the preloading magnet is a scanning exposure apparatus characterized by orthogonal to the step direction.

According to the present invention, in the static pressure stage for a scanning exposure apparatus, the magnets of the rectangular magnet pieces constituting the preload magnet and the direction along the short side direction (short side direction) are perpendicular to the scan axis, that is, the longitudinal direction of the rectangular magnet pieces. By arranging so that is parallel to the scan axis, the thrust resistance of the preload magnet can be reduced. Further, in the static pressure stage for a scanning exposure apparatus, the magnets of the rectangular magnet pieces constituting the preload magnet and the direction along the short side direction (short side direction) are perpendicular to the step direction, that is, the longitudinal direction of the rectangular magnet pieces is the step direction. By arranging them in parallel, the thrust disturbance due to the preload magnet can be reduced. Further, by selecting the surface plate material, the thrust resistance or the thrust disturbance can be further reduced.
According to the present invention, by reducing the scan resistance caused by the thrust force of the preload magnet, it is possible to reduce heat generation and improve overlay accuracy when combined with a multiphase motor. Further, it is possible to improve the image performance in the direction perpendicular to the scan by reducing the servo disturbance caused by the thrust force of the preload magnet.
Furthermore, it is possible to establish a system for placing the surface plate directly.

Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, the components of the stage are the same as those in FIGS. However, although the material of the base surface plate 1 is SKS in the conventional example, it is made of a Ni-based casting material in the present example and the second example. When the preload magnet moves from one position to another, the resistance of the preload magnet is not completely lost even if the SKS magnetization at the position where the magnet originally existed is lost. It is caused by trying to prevent. That is, it is caused by the magnetic hysteresis of the material. The resistance resulting from this magnetic hysteresis is proportional to the area enclosed by the BH curve of the material. Therefore, as the material for the surface plate and the yaw guide, a material having a small area surrounded by the BH curve is desirable.

On the other hand, since the surface plate 1 and the yaw guide 2 must fulfill the function of the magnet as a material to be attracted, it is desirable that the magnetic flux is sufficiently passed, that is, the saturation magnetic flux density is large.

There is a Ni-based casting as a material that satisfies both of these requirements.

It is.

A comparison of BH curves between SKS and Ni castings is shown in FIG. In the Ni-based casting, the area of the BH curve is much smaller than that of SKS. On the other hand, the saturation magnetic flux density can be expected to be about 0.8 T or more, and it can be seen that a considerable attractive force can be expected.

FIG. 1 is a view for explaining a first embodiment of the present invention, and is an X stage 4 and a Y stage 3 with Y as a scanning direction and X as a step direction as viewed from below. In both the X stage 4 and the Y stage 3, the magnets of the rectangular magnet pieces constituting the preload magnets 4 e and 3 e and the direction along the magnet pieces (the short side direction of the magnet pieces) are perpendicular to the scan axis (Y axis). That is, the magnet pieces are arranged so that the longitudinal direction thereof is parallel to the scan axis. The reason for this arrangement is that in Ni-based castings, when scanning is performed at right angles to the long side (longitudinal direction) of the rectangular magnet piece, there is uneven resistance synchronized with the magnetic pole pitch. The circumstances around this will be described below.

FIG. 3 shows the relationship between the position and resistance force when two preload magnets (corresponding to X stage 4) are scanned perpendicularly to the long side of the rectangular magnet and when they are scanned in parallel. It is the figure shown about. VS, PS, VN, and PN are amounts equivalent to twice the scanning resistance, but the measured values are

It is. By using a Ni-based material, the scanning resistance is reduced as expected. Further, in the case of a Ni-based right angle, about 30 g peak-to-peak unevenness is generated in synchronization with the magnetic pole pitch (for example, 7.5 mm).

FIG. 4 shows the relationship between the position and resistance force when two preload magnets (corresponding to X stage 4) are moved minutely (about 1 μm) perpendicularly to the long side of the rectangular magnet and when they are moved minutely in parallel. And Ni castings. The slope of each straight line corresponds to the spring constant in the thrust direction generated by the preload magnet, but the measured value is

It is. This value is an indicator of ease of transmission of the horizontal component of floor vibration. This is also reduced as expected by using a Ni-based material.

The Ni-based parallel direction has no unevenness in scanning, has a small value, and has a small spring constant for minute displacement. Therefore, it is preferable to adopt it for both scanning and minute movement. Since the Y stage 3 moves relative to the base surface plate 1 in one dimension only in the Y direction, such an arrangement is possible.

On the other hand, the current X stage 4 moves two-dimensionally relative to the base surface plate 1 and receives thrust resistance from the magnet 4e in both XY directions. Therefore, only one of XY can adopt the parallel direction of the long side of the magnet. The problem is how to arrange this most preferred direction.

Therefore, if the short side direction of the rectangular magnet piece is arranged at a right angle to the scan axis (the longitudinal direction of the magnet piece is parallel) with a stage in which Y is in the scan direction as in the present embodiment, there is no uneven running resistance during scanning. , Thrust disturbance caused by unevenness is eliminated.

Further, the spring constant in the scanning direction, which is an index of floor vibration transmission, is not zero as shown in Table 3, but almost zero. This is because even if the servo error during scanning takes a positive or negative value with respect to the target value, the absolute value of the position continues to increase and is always in a large displacement region, so a substantially constant force is applied.

On the other hand, in the direction perpendicular to the scan, only vibration transmission from the floor may be considered, but as shown in Table 3, the spring constant is 223 g / mm, which is about 1/8 that of SKS.

When Y is in the scan direction, the longitudinal direction of the rectangular magnet piece is parallel to the scan axis in both the X stage 4 and the Y stage 3 as shown in this embodiment in order to minimize the uneven thrust resistance during the scan. Must be arranged as follows. In the scan operation of Y scan, the integrated body of the X stage 4 and the Y stage 3 is scanned by the Y linear motor. Therefore, if either one of the rectangular magnet pieces is parallel to the scan axis, the scan resistance is uneven. Because it comes out. In this case, vibration transmission in the direction perpendicular to the scan is transmitted only from the X stage 4. This is because the portion from the Y stage 3 is insulated by the air slide between the X stage 4 and the Y stage 3.

FIG. 5 is a view for explaining a second embodiment of the present invention, and shows the X stage 4 and the Y stage 3 as viewed from below, where X is the scanning direction and Y is the step direction. The X stage 4 is arranged such that the magnets of the rectangular magnet pieces constituting the preload magnet 4e and the direction along which the preload magnet 4e is aligned (the short side direction) are perpendicular to the scan axis, and the Y stage 3 constitutes the preload magnet 3e. The magnets of the rectangular magnet piece and the direction along the short side (short side direction) are arranged in parallel with the scan axis.

This arrangement is also based on the fact that resistance unevenness is not generated in the scanning direction. From this point of view alone, it seems that the long side of the rectangular magnet piece of the Y stage 3 may face either direction XY. This is because, in the X scan, only the X stage 4 is scanned by the X linear motor, so that resistance unevenness does not occur from the Y stage 3 regardless of the orientation of the rectangular magnet piece of the Y stage 3.

On the other hand, considering vibration transmission from the floor, it is desirable that the short side direction of the rectangular magnet piece of the Y stage 3 be parallel to the scanning direction as in this embodiment. In this way, the floor vibration in the direction perpendicular to the scan is not easily transmitted to the Y stage 3, and the floor vibration in the scan direction is easily transmitted. The vibration in the direction perpendicular to the scan transmitted to the Y stage 3 is transmitted to the X stage 4 through the yaw guide. On the other hand, the vibration in the scanning direction transmitted to the Y stage 3 is insulated by the yaw guide and is not transmitted to the X stage 4. As a result, the total floor vibration via the Y stage 3 is hardly transmitted to the X stage 4 in total.

In this embodiment, the components of the stage are the same as those in FIGS. However, the material of the base surface plate 1 is SKS in the conventional example, but in the third and fourth embodiments, it is a low carbon iron-based material. When the resistance of the preload magnet to move from one location to another preload magnet originally remaining portion not eliminated completely even magnetization of SKS position for which the magnets are gone magnet, which prevents the movement of the magnet It occurs because of trying. That is, it is caused by the magnetic hysteresis of the material. The resistance resulting from this magnetic hysteresis is proportional to the area enclosed by the BH curve of the material. Therefore, as the material for the surface plate 1 and the yaw guide 2, a material having a small area surrounded by the BH curve is desirable.

On the other hand, since the surface plate and the yaw guide must function as a magnet attractant, it is desirable that the magnetic flux be sufficiently passed, that is, the saturation magnetic flux density is large.

As a material that satisfies both of these requirements, there is a low-carbon iron-based material. Specifically, pure iron or S10C is used. In the case of pure iron, it is desirable to add impurities other than carbon in order to improve workability.

A comparison of BH curves between SKS and pure iron is shown in FIG. With pure iron, the area of the BH curve is much smaller than that of SKS, while the saturation magnetic flux density is about 1.6 T or more, and there is no problem with the attractive force.

FIG. 6 is a view for explaining a third embodiment of the present invention, and shows the X stage 4 and the Y stage 3 as viewed from below, where Y is the scanning direction and X is the step direction. In Y stage 3 it is disposed so that the magnet and a direction perpendicular rectangular magnet pieces which constitute the preloading magnet 3e (longitudinal direction of the magnet piece) is parallel to the scan direction (Y-axis), the preload in the X stage 4 The magnets of the rectangular magnet pieces constituting the magnet 4e and the perpendicular direction (longitudinal direction of the magnet pieces) are arranged perpendicular to the scan direction (Y axis) and parallel to the step direction (X axis). .

The circumstances around this will be described below. FIG. 8 shows the relationship between the position and resistance force when two preload magnets (corresponding to X stage 4) are scanned perpendicularly to the longitudinal direction of the rectangular magnet piece and when they are scanned in parallel. It is the figure shown about. VS, PS, VJ, and PJ are amounts corresponding to twice the scanning resistance.

It is. By using a low-carbon iron-based material, the scanning resistance is reduced as expected. FIG. 9 shows the relationship between the position and resistance force when two preload magnets (corresponding to X stage 4) are moved minutely (about 1 μm) perpendicularly to the short side direction of the rectangular magnet piece and when they are moved minutely in parallel. Is shown for each of SKS and pure iron. The slope of each straight line corresponds to the spring constant in the thrust direction generated by the preload magnet, but the measured value is

It is. This value is an index of the ease of transmitting the horizontal component of floor vibration to the stage held at the same position. This is also reduced as expected by using a low-carbon iron-based material.

Since the pure iron parallel direction has no unevenness in scanning and a small value and a small spring constant of minute displacement, it is preferable to adopt it in both scanning and minute movement. Since the Y stage 3 moves relative to the base surface plate 1 in one dimension only in the Y direction, such an arrangement is possible.

On the other hand, the current X stage 4 moves two-dimensionally relative to the base surface plate 1 and receives thrust resistance from the magnet 4e in both XY directions. Therefore, only one of XY can adopt the parallel direction of the long side of the magnet. The problem is how to arrange this most preferred direction.

Therefore, if the longitudinal direction of the strip magnet piece is arranged at right angles to the scanning direction on the stage where Y is in the scanning direction as in this embodiment, the spring constant in the direction perpendicular to the scanning (during step) is minimized to 25 g / mm. be able to. At this time, the spring constant in the scanning direction is as large as 260 g / mm, but this is a stationary story, and is almost zero during scanning. This is because even if the servo error during scanning takes a positive or negative value relative to the target value, the movement by scanning is dominant, so the relative displacement between the magnet and the surface plate increases monotonically with time. This is because the resistance received from the magnet is almost constant. In this way, horizontal vibration transmission from the floor can be minimized. On the other hand, the scan resistance is 60 g as shown in Table 4, which is larger than 10 g when the longitudinal direction of the magnet piece is parallel to the scan direction, but is sufficiently smaller than SKS.

When Y is the scanning direction, as shown in the present embodiment, the Y stage 3 is preferably arranged so that the longitudinal direction of the rectangular magnet pieces is parallel to the scanning direction. This is because in the scanning operation of the Y scan, the integrated body of the X stage 4 and the Y stage 3 is scanned by the Y linear motor, so that the scanning resistance of scanning can be reduced in this way. In other words, if this is not done, an unnecessary scanning resistance is obtained from the Y stage 3, resulting in uneven thrust in combination with the drive system.

On the other hand, when considering from the floor vibration transmission surface, the spring constant in the scanning direction during scanning is almost zero in the Y stage 3 as well. The spring constant in the direction perpendicular to the scan is a larger value of 260 g / mm in the Y stage 3, and floor vibration is transmitted to the Y stage 3 as it is, but the X stage 4, that is, the stage on which the wafer is mounted, is a yaw guide. Since the vibration in the direction perpendicular to the scan at 2 is insulated, there is no problem even if a certain amount of floor vibration is transmitted to the Y stage 3.

FIG. 10 is a view for explaining a fourth embodiment of the present invention, and is a view of the X stage 4 and the Y stage 3 with X as the scanning direction and Y as the step direction as viewed from below. In the X stage 4, the magnets of the rectangular magnet pieces constituting the preload magnet 4 e and the direction along the short side direction (short side direction) are arranged in the scanning direction, and the Y stage 3 also forms a rectangular shape constituting the preload magnet 3 e. These magnet pieces are arranged so that the magnet and the direction along the magnet piece (short side direction) are the scanning direction.

This arrangement is also based on minimizing floor vibration transmitted to the X stage 4. As in the third embodiment, the spring constant in the direction perpendicular to the scan (during step) is 25 g / mm, and the spring constant in the scan direction (during scan) is almost zero.

In this example, scanning is performed only by the X stage 4 and the Y stage 3 is stationary, so that the direction of the magnet 3e of the Y stage 3 seems to be either XY from the viewpoint of scanning resistance.

However, considering vibration transmission from the floor 30, it is desirable that the longitudinal direction of the rectangular magnet piece of the Y stage 3 is also perpendicular to the scanning direction as in this embodiment. In this way, the floor vibration in the direction perpendicular to the scan is not easily transmitted to the Y stage 3, and the floor vibration in the scan direction is easily transmitted. Of the vibrations transmitted to the Y stage 3, only vibrations in the direction perpendicular to the scan are transmitted to the X stage 4. This is because the vibration in the scanning direction is insulated by the yaw guide 2. As a result, the total floor vibration via the Y stage 3 is hardly transmitted to the X stage 4 in total.

It is a bottom view of the wafer stage which concerns on 1st Example of this invention. It is a BH curve comparison figure of the surface plate material used for the stage of FIG. It is a scanning resistance comparison figure by the direction of the surface plate material and pre-load magnet used for the stage of FIG. It is a spring constant comparison figure by the direction of the surface plate material and preload magnet used for the stage of FIG. It is a bottom view of the wafer stage which concerns on 2nd Example of this invention. It is a bottom view of the wafer stage which concerns on 3rd Example of this invention. It is a BH curve comparison figure of the surface plate material used for the stage of FIG. It is a scanning resistance comparison figure by the direction of the surface plate material and preload magnet used for the stage of FIG. It is a spring constant comparison figure by the direction of the surface plate material and preload magnet used for the stage of FIG. It is a bottom view of the wafer stage which concerns on 4th Example of this invention. It is a whole view of the wafer stage which is a prior art example and is an application object of this invention. FIG. 12 is an exploded view of the wafer stage of FIG. 11. It is a magnet unit figure as a preload magnet. 1 is an overall view of a scanning exposure apparatus as an application target example of a stage of the present invention. FIG. 10 is an overall view of another scanning exposure apparatus as an example to which the stage of the present invention is applied.

Explanation of symbols

1: Base surface plate, 2: Y yaw guide, 3: Y stage, 3a: X yaw guide, 3b: Y slider large, 3c: Y slider small, 3e: Preload magnet, 4: X stage, 4a: X stage side plate, 4b : X stage top plate, 4c: X stage bottom plate, 4d: Air pad, 4e: Preload magnet, 6a, 7a: Stator, 6b, 7b: Mover, 6c, 7c: Coil, 7d: Magnet coupling plate, 8: Y Stator fixing member, 30: floor (or ground), 31: vibration isolation means, 33: wafer stage, 34: lens barrel support member, 35: reduction projection optical system, 36: reticle stage base, 37: reticle stage, 38 : Illumination system, 41: outer cylinder, 42, 43: interferometer reference, 45: lens barrel surface plate.

Claims (8)

A first stage that is movable in the first direction on the surface plate along a first guide provided on the surface plate, and a second guide provided on the first stage. A second stage movable in a second direction intersecting the first direction on the surface plate, and the first and second stages provided on the first and second stages respectively on the surface plate First and second hydrostatic pressure applying means for floating and first and second provided on the first and second stages for sucking the first and second stages toward the surface plate, respectively. In the static pressure stage used in a scanning exposure apparatus having a preload magnet, the surface plate is made of a low-carbon iron-based material, and the first and second preload magnets each include a plurality of rectangular magnet pieces. It is arranged in a one-dimensional manner with its sides in contact with each other, Static pressure stage, characterized in that the one-dimensional magnets and along the direction of the magnet pieces constituting the magnet is orthogonal to the step direction. The first direction and the second direction are orthogonal to each other, and the wafer is disposed as a wafer stage in a scanning exposure apparatus in which one of these directions is a scanning direction and the other is a step direction. Item 1. The static pressure stage according to Item 1. 3. The hydrostatic stage according to claim 2, wherein the first direction is a scanning direction, and the scanning direction is orthogonal to a direction along a one-dimensional magnet of the magnet piece constituting the first preloading magnet. . 3. The hydrostatic stage according to claim 2, wherein the second direction is a scan direction, and the scan direction is orthogonal to a direction along which the one-dimensional magnets constituting the first preload magnet are aligned. . 5. The surface plate is installed on a floor via vibration isolation means, and a projection optical system and a reticle stage constituting the scanning exposure apparatus are mounted on the surface plate. The static pressure stage according to any one of the above. The surface plate is directly connected to the floor without the vibration isolation means, and the projection optical system and the reticle stage constituting the scanning exposure apparatus are mounted on another surface plate installed on the floor via the vibration isolation means. The static pressure stage according to claim 1, wherein the static pressure stage is provided. The static pressure stage according to claim 1, wherein the fluid for generating the static pressure is air. A first stage that is movable in the first direction on the surface plate along a first guide provided on the surface plate, and a second guide that is provided on the first stage. A second stage movable in a second direction intersecting the first direction on the surface plate, and the first and second stages provided on the first and second stages respectively on the surface plate First and second hydrostatic pressure applying means for floating and first and second provided on the first and second stages for sucking the first and second stages toward the surface plate, respectively. In the static pressure stage used in a scanning exposure apparatus having a preload magnet, the surface plate is made of a low-carbon iron-based material, and the first and second preload magnets each include a plurality of rectangular magnet pieces. It is arranged in a one-dimensional manner with its sides in contact with each other, Scanning exposure apparatus in which one-dimensional magnets and along the direction of the magnet pieces constituting the magnet is equal to or orthogonal to the step direction.