JPH10256356A - Positioning device, and exposure device provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To position such flat object as semiconductor wafer at a high speed and precision. SOLUTION: Drive units 17A and 17AR are allocated with a specified pitch in X and Y directions over the entire surface of a drive base 4, and a compressed air is blown from air supply holes 13A and 13AR formed at the center part of respective drive units 17A and 17AR to jet a mirror plate 7 and a wafer W float, and they are held. The position of the mirror plate 7 is measured with laser interferometers 8X, 8YA, and 8YB, and a relative position of the wafer W against the mirror plate 7 is measured with displacement gauges 31A-31E. Respective drive units 17A and 17AR generate, to the mirror plate 7 and the wafer W, Y-direction drive force (Lorentz force) FY and X-direction drive force (Lorentz force) FX respectively, and the wafer W is positioned by combining these drive forces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning device for positioning a flat object such as a semiconductor wafer in a non-contact manner, and an exposure apparatus provided with the positioning device.

[0002]

2. Description of the Related Art Conventionally, semiconductor devices, liquid crystal display devices,
Alternatively, in a photolithography process for manufacturing a thin-film magnetic head or the like, a projection exposure apparatus that transfers a reticle pattern as a mask to each shot area of a wafer (or a glass plate or the like) as a photosensitive substrate via a projection optical system ( And a proximity type exposure apparatus that transfers a reticle pattern directly onto a wafer. In such an exposure apparatus, since it is necessary to position the wafer at the exposure position with high precision, the wafer is held on a wafer holder by vacuum suction or the like, and this wafer holder is fixed on a wafer stage that can be positioned with high precision. I have.

FIG. 12 shows an example of a wafer stage of a conventional exposure apparatus. In FIG.
The Y stage 102 is mounted on the Y stage 102 so as to be driven in the Y direction by a drive motor.
The stage 103 is mounted so as to be driven in the X direction by a drive motor. Further, a stage 104 is mounted on the X stage 103, a wafer holder 105 is fixed on the stage 104, and a wafer 106 is held on the wafer holder 105 by vacuum suction. Further, orthogonal movable mirrors 107 and 108 for a laser interferometer are also fixed on the stage 104 near the wafer holder 105. In this case, the stage 104 positions the wafer 106 in the Z direction and the rotation direction around an axis parallel to the Z axis, and at the same time, tilts the wafer 106 (that is, each of the axes parallel to the X axis and the Y axis). (Angle of rotation about an axis).

If the wafer is locally distorted such as curvature, a reticle image cannot be transferred with high resolution in a shot area close to such an area. Therefore, a method has been proposed in which a large number of piezoelectric elements are embedded in parallel inside the wafer holder 105 and the flatness of the wafer held thereon is controlled by partially controlling the amount of expansion and contraction of these piezoelectric elements. ing.

[0005]

As described above, the wafer stage of the conventional exposure apparatus is constructed by stacking various stages and a stage on a wafer base, and the position of the wafer on the stage is determined by, for example, a feed screw. This was done by a drive motor of the type. In this regard, in recent years, as semiconductor elements and the like have been increasingly miniaturized, it has been required to further increase the positioning accuracy of the wafer stage.
In addition, since it is desired to improve the throughput (productivity) in the manufacturing process of the semiconductor element and the like, the wafer stage is also required to improve the positioning speed.

In order to position the stage (wafer) at high speed and with high accuracy in the conventional wafer stage having the stacked structure, a driving motor having a large power is required. The use of a drive motor results in an increase in the size and weight of the device configuration, and as a result, there has been a disadvantage that the positioning speed cannot be increased so much. Further, when a driving motor having a large power is used, the stage and the wafer are thermally deformed by the influence of heat generated by the driving motor, so that the positioning accuracy may be deteriorated.

In the prior art in which a large number of piezoelectric elements are embedded in a wafer holder in order to improve local distortion of the wafer, it is necessary to provide a large number of high-voltage wirings for the piezoelectric elements in the wafer holder. However, there has been a problem that the size of the wafer holder is increased, the positioning speed is reduced, and the manufacturing cost is increased. In view of the above, an object of the present invention is to provide a positioning device that can position a flat object such as a wafer at high speed and with high accuracy.

Another object of the present invention is to provide a positioning device capable of improving the local distortion of such a flat object without increasing the size of the device configuration. Furthermore,
It is another object of the present invention to provide an exposure apparatus having such a positioning device and capable of manufacturing a semiconductor element or the like with high throughput and high accuracy.

[0009]

A first positioning device according to the present invention is a positioning device for positioning a flat object (W) made of an electric conductor on a predetermined base (4), and is substantially a positioning device. A flat holding member (7) made of a rectangular electric conductor and having a through hole (7a) in the center portion for storing the flat object (W); a flat object (W) and a flat holding member (7); ) On the base (4).
16) and current generators (18A, 18B, 2) for inducing current in the flat object (W) and the flat holder (7), respectively.
5) and a magnetic field generator (19, 20, 2) for generating a magnetic field in a direction crossing the current induced by the current generator.
8), and generates a driving force of Lorentz force on the flat object (W) and the flat holding member (7) in a direction orthogonal to the current and the magnetic field, and the generated driving force W) and a driving device (17A) for moving the flat holding member (7) along the surface of the base (4)
A first displacement measuring device (8X, 8YA, 8YB) for measuring the displacement of the plate-like holder (7), and a second displacement measuring device for measuring the displacement of the plate-like object (W) with respect to the plate-like holder (7).
And a plate-like holding member (7) and a plate-like object () via a driving device (17A) based on the measurement results of the first and second displacement measuring devices. W) is moved to position the flat object (W) in a non-contact state.

According to the present invention, the levitation device causes the flat holding body (7) and the flat object (W) to float on the predetermined base (4). In this state, a current is induced in the inside by the current generating unit of the driving force generating device, a magnetic field is generated by the magnetic field generating unit in a direction crossing the current, and the magnetic field is orthogonal to the direction of the current and the magnetic field. A Lorentz force is generated in the direction, and the flat holding body (7) and the flat object (W) are displaced by the Lorentz force. The position of the flat object (W) is accurately obtained by correcting the measurement value of the first displacement measurement device with the measurement value of the second displacement measurement device, and based on the detection result, Flat holding body by Lorentz force (7)
By controlling the displacement of the flat object (W) and the flat object (W), the flat object (W) is positioned at high speed and with high accuracy in a non-contact state. In particular, when the flat object is a semiconductor wafer, since the semiconductor wafer weighs about 100 g even with an 8-inch wafer, the semiconductor wafer can easily float and can be easily displaced by Lorentz force.

In this case, an example of the levitation device is an air supply device (14 to 16) for ejecting a compressed gas from an opening (13A) formed on the base (4). (W) and the back surface of the flat holding member (7) are floated by spraying them. Another example of the levitation device is a flat object (W) and a flat support (7).
Consisting of a pair of suction electrodes (36A) arranged above
This is a device in which a predetermined voltage is applied between the pair of suction electrodes, and the flat object (W) and the flat holding member (7) are suction-floated by electrostatic suction force.

One example of the current generating section is a plurality of electrodes (18A, 18A) arranged on the surface of the base (4).
B), a predetermined drive voltage is applied between the adjacent electrode pairs (18A, 18B), and areas on the flat object (W) and the flat holding member (7) facing these electrode pairs. This is a device that allows current to flow between them. In this case, a capacitance detecting a change in capacitance caused by a change in the distance from the front surface of the current generating electrodes (18A, 18B) to the back surface of the flat object (W) and the flat holding member (7). Capacity detection device (2
It is desirable to further include 6), and to measure the distance (gap) between the flat object (W) and the rear surface of the flat holding member (7) based on the detection result of the capacitance detecting device. According to this, the electrode for generating current can be used also as a gap sensor, so that the structure can be simplified. Further, by measuring the gap with three electrodes on the back surface of the flat object (W), the inclination angle of the object can be detected.
By measuring the gap with the electrodes at or above the location, distortion such as the curvature of the object can also be measured.

The first displacement measuring device is disposed so as to face a side surface of the flat holding member (7) floated by the floating device, and is provided at least at three positions on the side surface of the flat holding member (7). Measuring device (8X, 8YA,
8YB), and the second displacement measuring device is disposed so as to face the outer peripheral surface of the flat object (W), and the flat displacement object (W)
A measuring device (31A to 31E) for measuring displacement at at least three places on the outer peripheral surface of the flat plate-shaped holding member (7) and the flat or flat object (W). A height measuring device (18A, 1A) for measuring a distance between the holding body (7) and the front surface or the back surface of the flat object (W).
8B, 26).

At this time, since there is usually a notch around the flat object (W), the second displacement measuring devices are arranged at three or more positions including the notch, and the height of the second displacement measuring device is increased. By measuring the gap (gap) at three or more locations on the bottom surface of the flat object (W) by the measuring device, the three-dimensional displacement of the flat object (W) and the six degrees of freedom including the rotation of three degrees of freedom are measured. Can be detected.

An example of the first displacement measuring device is as follows.
Laser interferometers (8X, 8YA, 8YB) for irradiating at least three points on the side surface of the plate-like holder (7) floated by the levitation device with measurement light beams. The displacement of the flat holding member (7) is measured based on the detected value. An example of the second displacement measuring device is a through-hole (7a) of a flat holding member (7).
A plurality of gap sensors (31A to 31E) for detecting a distance from an inner wall of the flat object to an outer peripheral surface of the flat object (W).
In this case, the displacement of the flat object (W) with respect to the flat holding member (7) is measured based on the detection values of the plurality of gap sensors.

Further, in the above-mentioned present invention, a suction force generating device (18A, 18B, 24) for sucking the plate-like holder (7) and the plate-like object (W) toward the base (4) is further provided. Is desirable. In the present invention, the flat holding member (7) and the flat object (W) are floated on the base (4) by the lifting device, and the floating force can be adjusted to some extent by adjusting the lifting force. The height of the body can be controlled. Further, by controlling the suction force by the suction force generator, the height of the flat object or the like can be more accurately controlled.

One example of the attraction force generating device is such that a predetermined voltage is applied between adjacent pairs of electrodes (18A, 18B) of the current generating portion to apply a predetermined voltage to the flat holding member (7) and the flat object (W). ) Is generated toward the base (4). According to this, the current generating electrode (1)
8A, 18B) can also be used as a part of the suction force generating device, so that the device configuration is simplified.

It is desirable to adjust the voltage applied between the adjacent electrode pairs (18A, 18B) of the current generating section for each set to correct the distortion of the flat object (W). With this method, the flatness of a thin and light object such as a semiconductor wafer can be improved in a non-contact manner without increasing the complexity and size of the apparatus. Next, a second positioning device according to the present invention is a positioning device for positioning a flat object (W) made of an electric conductor on a predetermined base (4A). A levitation device (14 to 16) for levitation on the base (4A), a current generation unit for inducing a current in the flat object (W), and a magnetic field in a direction intersecting the current induced by the current generation unit A magnetic field generator is provided to generate a driving force of Lorentz force in a direction perpendicular to the direction of the current and the magnetic field to the flat object (W), and the generated driving force causes the flat object (W) to be a base. (4A) Driving device (17) for moving along the surface
A) and a measuring device (18A, 18B, 26A) for measuring a relative position of the flat object (W) with respect to the base (4A).
And positioning the flat object (W) in a non-contact state via the driving device (17A) based on the position of the flat object (W) measured by the measuring device.

According to the second positioning device of the present invention, the flat object (W) floats independently and is positioned at high speed. Therefore, for example, when the flat object (W) is a semiconductor wafer, the position cannot be detected by irradiating the side surface of the flat object (W) with a laser beam. Therefore, in the present invention, the displacement of the flat object (W) in the lateral direction with respect to the base (4) is detected on the bottom side of the flat object (W) by using the measuring device, and the detection result is more accurate. Perform positioning.

In this case, one example of the measuring device is a plurality of electrodes (18A, 18A) arranged on the surface of the base (4).
B), and measures the position of the flat object (W) based on a change in capacitance generated between the back surface of the flat object (W) and the plurality of electrodes (18A, 18B). is there.
Next, an exposure apparatus of the present invention includes the above-described first or second positioning apparatus of the present invention, and exposes a mask pattern image on a semiconductor wafer (W) positioned by the positioning apparatus. In this case, since the semiconductor wafer (W) is an electric conductor, the semiconductor wafer (W) can be driven at high speed without contact by the positioning device of the present invention. Further, since the semiconductor wafer (W) is held in a non-contact manner, the semiconductor wafer (W) is not affected by foreign substances on the back surface thereof.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In this embodiment, the present invention is applied to a positioning section of a semiconductor wafer in a projection exposure apparatus. FIG. 1 is a schematic configuration diagram showing a projection exposure apparatus of the present embodiment. In FIG. 1, exposure light (bright line such as i-line of a mercury lamp or excimer laser light) IL from an illumination optical system 1 is used. The pattern formed on the lower surface of the reticle R is illuminated with a uniform illuminance distribution, and the pattern of the reticle R is exposed to a predetermined reduction magnification β (β is, for example, １ ／, １ ／) and projected onto a predetermined shot area on a semiconductor wafer (hereinafter simply referred to as “wafer”) W. A photoresist is applied to the surface of the wafer W. Hereinafter, the Z axis is taken in parallel with the optical axis AX of the projection optical system 3, the X axis is taken in a plane perpendicular to the optical axis AX, in parallel with the plane of FIG. 1, and the Y axis is taken in the plane perpendicular to the plane of FIG. explain.

The reticle R is held on a reticle stage 2 that can be finely moved in the X direction, the Y direction, and the rotation direction, and the position of the reticle stage 2 is controlled based on a measurement value of a laser interferometer (not shown). . On the other hand, the wafer W of the present example
Is housed inside a mirror plate 7 as a flat holding member, and the wafer W and the mirror plate 7 are held in a floating state on a drive base 4 in a non-contact manner, and the drive base 4 is placed on a surface plate (not shown). Fixed. The levitation force of the wafer W and the mirror plate 7 is given by compressed air blown out from the upper surface of the drive base 4, and the compressed air is driven from an external air supply source 15 via a flow control valve 14 and an air supply pipe 16. A main control system 9, which is supplied to the base 4 and supervises and controls the operation of the entire apparatus, controls the flow rate in the flow control valve 14 (details will be described later).

FIG. 2 is a plan view of the drive base 4 of FIG. 1. In FIG. 2, the -X direction of a rectangular plate-like mirror plate 7 surrounded by sides substantially parallel to the X axis and the Y axis. The side surface 7x and the side surface 7y in the + Y direction are mirror-finished, and the side 7x is irradiated with a laser beam from the laser interferometer 8X in parallel with the X-axis, and two side-by-side laser interferometers are arranged on the side surface 7y Laser beams from 8YA and 8YB are irradiated in parallel to the Y axis. Laser interferometer 8X, 8Y
A and 8YB measure the displacements of the corresponding side surfaces 7x and 7y at a resolution of, for example, about 0.001 μm to 0.01 μm, and output the measurement results to the main control system 9 in FIG. In this case, for example, the X coordinate and the Y coordinate of the mirror plate 7 are obtained from the measured value of the laser interferometer 8X and the average value of the measured values of the laser interferometers 8YA and 8YB, respectively.
The rotation angle of the mirror plate 7 is obtained from the difference between the measurement values of the two laser interferometers 8YA and 8YB.

The mirror plate 7 is, for example, a metal plate,
Or formed from an electrical conductor such as conductive ceramics,
A circular through hole 7a is formed inside the mirror plate 7, and the wafer W is stored in the through hole 7a. Furthermore,
Capacitive displacement gauges 31A to 31E are provided in the through-holes 7a of the mirror plate 7 to detect the distance to the contour (edge) of the wafer W, respectively.
The detection result of 31E is supplied to the main control system 9 in FIG. These displacement meters 31A to 31E are manufactured by a fine processing technique used when manufacturing a micromachine or the like.

At this time, the displacement gauges 31D and 31E measure the rotation angle of the wafer W with respect to the mirror plate 7 so that the orientation flat portion W on the outer periphery of the wafer W is used.
It is arranged so as to face both ends of F. The remaining three displacement gauges 31A to 31C are arranged at approximately 90 ° intervals along the arc-shaped outer periphery of the wafer W in order to measure the amount of displacement of the wafer W in the X direction and the Y direction with respect to the mirror plate 7. ing. In this example, the displacement meters 31D, 31
E is arranged corresponding to the orientation flat portion OF, but in the case of a wafer having a notch portion,
The arrangement of the displacement meters 31D and 31E may be changed accordingly. Further, the arrangement and the number of the displacement meters 31A to 31E can be changed within a range in which the displacement of the wafer W in the X direction and the Y direction with respect to the mirror plate 7 and the rotation angle can be detected.

The main control system 9 shown in FIG. 1 includes the measured values of the laser interferometers 8X, 8YA, 8YB and the displacement meters 31A to 31A.
From the measurement value of 31E, the X coordinate of the wafer W on the XY plane,
Calculate the Y coordinate and the rotation angle. Further, as described later, the wafer W and the mirror plate 7
Function of displacing the wafer in a non-contact manner in the XY plane, and the wafer W
And a function of controlling the position (height) of the mirror plate 7 in the Z direction, the tilt angle, and the like. Therefore, FIG.
In the above, the main control system 9 controls the operation of the drive base 4 via the wafer drive unit 21 based on the position and the rotation angle of the wafer W in the XY plane obtained as described above, thereby The mirror plate 7 is positioned. At this time, since the displacement meters 31A to 31E can also measure the expansion and contraction (change in magnification, etc.) of the wafer W, according to the present embodiment, it is possible to improve the overlay accuracy of each shot area of the wafer W and the reticle image.

Although not shown, a slit image or the like is projected on the side surface of the projection optical system 3 on the surface of the wafer W, and the lateral shift amount of the slit image re-imaged by the reflected light from the wafer W. An oblique incidence type focus position detection system for detecting the defocus amount of the wafer W is also provided, and based on the output of the focus position detection system, the main control system 9 controls the drive base 4 in the auto focus method and the auto leveling method. The control of the position and the tilt angle of the wafer W in the Z direction is performed via the. Since the drive base 4 of the present example also has a function of measuring the distance between the wafer W and the mirror plate 7 as described later, the oblique incidence type focus position detection system may be omitted. At the time of exposure, when exposure to a certain shot area on the wafer W is completed, the wafer W is stepped through the drive base 4 in a non-contact and high-speed manner so that the next shot area becomes an exposure field of the projection optical system 3. After moving and positioning with high precision, the operation of projecting and exposing the pattern image of the reticle R to the shot area is repeated in a step-and-repeat manner, and the exposure of each shot area of the wafer W is repeated. Done.

As described above, the wafer W and the mirror plate 7 of this embodiment are held on the drive base 4 in a non-contact floating state at a predetermined interval. Further, the drive base 4 is provided with a mechanism for positioning the wafer W and the mirror plate 7 in a non-contact manner. Hereinafter, a non-contact holding mechanism and a positioning mechanism of the wafer W and the mirror plate 7 by the drive base 4 will be described.

First, as shown in FIG. 2, the pitch PX in the X direction and the pitch P in the Y direction are provided inside the entire area where the wafer W and the mirror plate 7 move on the drive base 4.
In Y, drive units 17A and 17AR having the same configuration are incorporated. In this case, one drive unit 17A is a unit that applies a drive force FY consisting of Lorentz force in the ± Y direction to the wafer W or the like on the upper surface thereof in a non-contact manner, and the other drive unit 17AR is a unit for applying the wafer W on the upper surface. W
And a drive unit for applying a driving force FX composed of Lorentz force in the ± X direction in a non-contact manner to
7AR is obtained by rotating the drive unit 17A by 90 °. In this example, the drive units 17A and 17AR are alternately arranged along the X direction and the Y direction, respectively, and the drive unit 17A (similarly, the drive unit 17AR) is provided.
AR) are arranged in a zigzag pattern as a whole, and the arrangement pitches PX and PY are set such that the drive units 17A and 17AR together on the bottom surface of the wafer W always fit within about 3 rows × 3 columns. I have. Also, the drive unit 17
At the center of A and 17AR are the air supply holes 13A and 1A, respectively.
3AR is formed and these air supply holes 13A and 13AR
Are all connected to the air supply pipe 16 of FIG.

FIG. 3 is a sectional view taken along the line AA in FIG. 2. In FIG. 3, only one of the drive units 17A is shown in a sectional view of the drive base 4, and the sectional view of the drive base 17 is 90 °.
The rotated drive unit 17AR is shown in a front view. As shown in FIG. 3, drive units 17A and 17AR are alternately arranged at a predetermined pitch on the bottom surface of the upper plate 32 of the drive base 4 (the upper plate 32 is omitted in FIG. 2). The central air supply hole 13A and the central air supply hole 13AR of each drive unit 17AR are connected to the air supply pipe 16 inside the drive base 4, respectively. Then, the compressed air (or compressed nitrogen gas or the like) inside the air supply source 15 is jetted from the air supply holes 13A and 13AR on the surface of the drive base 4 through the air supply pipe 16 so that the compressed air layer is used. The wafer W and the mirror plate 7 float by the same operation as the static pressure air bearing. At this time, the floating amount of the wafer W and the mirror plate 7 can be controlled to some extent by the main control system 9 controlling the flow rate of the compressed air passing through the flow control valve 14. Even if the wafer W and the mirror plate 7 move in the X direction and the Y direction, since the drive units 17A and 17AR are arranged inside almost the entire surface of the drive base 4 of this example, the wafer W
The mirror plate 7 moves while floating over the entire surface of the drive base 4. Next, typically, the drive unit 17A,
The configuration of the driving circuit will be described with reference to FIGS.

FIG. 4 is an enlarged view of a part of FIG.
As shown in FIG. 4, on the bottom surface of the upper plate 32 of the drive base 4, electrodes 18A, 18B, 18C, 18 made of a flat metal elongated in the Y direction, which are a part of the drive unit 17A, are provided.
D is arranged in the X direction. In this case, the distance in the X direction between the first pair of electrodes 18A and 18B is equal to the distance in the X direction between the second pair of electrodes 18C and 18D, and the distance between the center electrodes 18B and 18C is: It is set wider than the distance between the first and second pairs of electrodes. Upper plate 32
Is formed of an insulator thinner than the wafer W as an example. A substantially E-shaped iron core (core) 19 is arranged below these electrodes 18A to 18D, and a magnetic pole 19a at the center of the iron core 19 is arranged between the electrode 18B and the electrode 18C. The magnetic poles 19b and 19c are located between a pair of electrodes 18A, 18B, respectively, and another pair of electrodes 1
8C, 18D and a central magnetic pole 19
The air supply hole 13A penetrates the center part of a. Further, a coil 20 is wound around the central magnetic pole 19a,
The coil 20 constitutes an electromagnet as a magnetic field generating unit. The iron core 19 is formed of a laminated silicon steel sheet so as to generate a rapidly changing AC magnetic field.

FIG. 5 is an enlarged perspective view of the driving unit 17A and a configuration diagram of the driving circuit 22A.
A control unit 23 including a microcomputer in the drive circuit 22A controls the operation of each circuit in the drive circuit 22A. The drive circuit 22A includes an electrostatic suction circuit 2
4. AC voltage generation circuit 25 and gap detection circuit 26
Is provided, and a variable DC voltage VA
1 is generated, the AC voltage generation circuit 25 generates an AC voltage VA2 having a predetermined frequency f1 and a variable amplitude, and the gap detection circuit 26 generates a high frequency (carrier frequency) f2 (> f).
The AC voltage VA3 of 1) is generated, and these DC voltages V
A1, the AC voltage VA2, and the AC voltage VA3 are combined in the combining circuit 27 as follows to become a voltage φA, and this voltage (potential difference) φA is applied to the pair of electrodes 18 of the drive unit 17A.
A is applied between A and 18B.

ΦA = VA 1 (DC) + VA 2 (frequency f 1) + VA 3 (frequency f 2) (1) In the drive circuit 22 A, an excitation circuit 28 and a partial drive circuit 29 are also provided.
7A, the frequency f
And the partial drive circuit 29 supplies the voltage (potential difference) φB to the electrode 18 in the drive unit 17A.
Applied between C and 18D. The voltage φB includes a DC voltage VB1 equal to the DC voltage VA1 generated by the electrostatic attraction circuit 24, an AC voltage VB2 having a frequency f1 equal to the AC voltage VA2 generated by the AC voltage generation circuit 25, and a gap as follows. AC voltage VA3 output from detection circuit 26
Is a voltage obtained by combining the AC voltage VB3 having the frequency f2.

ΦB = VB 1 (DC) + VB 2 (frequency f 1) + VB 3 (frequency f 2) (2) In this case, the synchronization signal S 1 is supplied from the AC voltage generation circuit 25 to the excitation circuit 28 and the partial drive circuit 29. , The component VA2 of the frequency f1 in the voltage φA, and the exciting current I
E and the component VB2 of the frequency f1 in the voltage φB change in synchronization with each other. The same drive circuit as the drive circuit 22A is provided in each of the other drive units 17AR, and these drive circuits constitute the wafer drive unit 21 in FIG.

Here, the driving unit 17 using the AC voltages VA2 and VB2 having the frequency f1 in the equations (1) and (2).
The basic operation of A will be described with reference to FIG. FIG.
As shown in FIG. 7, at some point, the AC voltage VA2 is applied to the electrode 18A.
Assuming that the side is higher than the electrode 18B side, the other AC voltage VB2 is also higher on the electrode 18C side than on the electrode 18D side. As a result, the wafer W above the electrodes 18A and 18B and the mirror plate 7 (not shown) have +
The current IA flows in the X direction, and the current IB also flows in the + X direction inside a wafer or the like above the electrodes 18C and 18D. Further, at this time, if the magnetic pole 19a at the center of the iron core 19 is an N pole and the magnetic poles 19b and 19c at both ends are S poles, a magnetic field is generated from the N pole to the S pole. A magnetic field BA is generated upward in the -Z direction so as to be orthogonal to the current IA, and a magnetic field BB is generated above the other magnetic pole 19c in the -Z direction so as to be orthogonal to the current IB. Accordingly, a Lorentz force FA is generated in the + Y direction on the wafer W and the mirror plate 7 (not shown) above the one magnetic pole 19b, and a Lorentz force FA is also generated on the wafer and the like above the other magnetic pole 19c in the + Y direction. FB occurs.

Further, in this embodiment, since the AC voltage VA2 and the exciting current IE are synchronized, when the potential of the electrode 18B becomes higher than that of the electrode 18A and a current flows in the -X direction,
The magnetic pole 19b becomes the N pole, and a magnetic field is generated in the + Z direction, and the Lorentz force FA is also generated in the + Y direction. Similarly, the direction of the Lorentz force FB generated above the magnetic pole 19c is also constant, and in this example, the two Lorentz forces FA and FB have the same magnitude and direction. To change the direction of the Lorentz forces FA, FB, the AC voltage VA2,
What is necessary is just to invert the phase of VB2 (the excitation current IE side is also possible). Then, by controlling the directions of the Lorentz forces FA and FB and the operation times thereof, the wafer W and the mirror plate 7 above the drive unit 17A can be displaced by a desired amount in the + Y direction or the −Y direction. . Generally, the wafer W is as light as about several tens g, and even an 8-inch wafer weighs about 100 g. Since the wafer W is floating, the wafer W can be easily moved by the Lorentz forces FA and FB. Also, as shown in FIG. 2, for example, the mirror plate 7 has a through hole 7a, so that the weight can be reduced and the mirror plate 7 can be easily moved by Lorentz force. For this reason, the control unit 23 in FIG. 5 outputs information on the directions and the operation times of the Lorentz forces FA and FB to be generated to the AC voltage generation circuit 25 and the partial drive circuit 29, and accordingly, the AC voltage generation circuit 25 Outputs the AC voltage VA2 for the operation time, and the exciting current I2 is synchronized with the AC voltage VA2.
B and the AC voltage VB2 are output.

Next, the operation of the AC voltages VA3 and VB3 having the high frequency f2 in the equations (1) and (2) will be described. FIG. 6 is a cross-sectional view showing the drive unit 17A.
In FIG. 6, an AC voltage VA3 is applied between the electrode 18A and the electrode 18B. Also, the electrodes 18A, 1
It can be considered that a capacitor having a capacitance C corresponding to the distance δA between the base plate 8B and the wafer W (here, the distance between the upper plate 32 and the bottom surface of the wafer W) is formed. Therefore, the capacitance C can be obtained from the value of the AC current flowing while the AC voltage VA3 is applied. That is, in the gap detection circuit 26 of FIG.
The capacitance C is obtained from the value of the alternating current flowing between the electrodes 18A and 18B in the state where A3 is applied.
A is obtained and output to the control unit 23. The capacitance C and the interval δ
The relationship with A is measured in advance using a standard wafer or the like,
A gap detection circuit 26 as a predetermined function or table
May be stored in the internal memory.

It is to be noted that the AC voltage V
The distance to the wafer is detected using B3, and the detection result is output to the control unit 23. As an example, the average value of the two intervals can be used as the interval between the drive unit 17A and the wafer. Similarly, the distance between the mirror plate 7 can be measured. However, since the distance between the mirror plate 7 and the mirror plate 7 does not need to be measured with high precision as compared with the wafer, the above-mentioned capacitance C and the distance δA can be measured.
For example, only the distance δA to the mirror plate 7 may be roughly measured by using, for example, a relation for a wafer.

Next, the operation of the DC voltages VA1 and VB1 in the equations (1) and (2) will be described. In FIG. 6, assuming that the potential on the electrode 18A side is higher than the electrode 18B side by the DC voltage VA1,
The bottom surfaces of the wafers W on A and 18B are charged negatively and positively, respectively, and an electrostatic attraction force 52A is generated between the electrodes 18A and 18B and the wafer W. This is the same even if the sign of the DC voltage VA1 is inverted. Similarly, the electrostatic attraction force 5 is also applied between the electrodes 18C and 18D and the wafer W by the DC voltage VB1.
2B occurs. Therefore, both electrostatic attraction forces 52A, 5A
By making 2B equal and variable, a variable suction force is applied to the wafer W from the drive base 4 in the −Z direction. At this time, in this example, the air supply hole 13A at the center of the drive unit 17A is used.
Compressed air is blown from the bottom of the wafer W to the wafer W, and a floating force 51 in the + Z direction also acts on the wafer W. Therefore, the controller 23 in FIG. 5 sets the electrostatic adsorption circuit 2 so that the interval δA detected by the gap detection circuit 26 becomes a predetermined target value.
AC voltages VA1 and V
An instruction to increase or decrease the size of B1 is issued. Thus, the distance δA between the wafer W and the upper plate 32 of the drive base 4 is set to a desired value.

Similarly, when the mirror plate 7 is located above the drive unit 17A, the AC voltages VA1 and VB
The distance to the mirror plate 7 is controlled by the size of 1. However, the height of the wafer W needs to be set with high accuracy, but the height of the mirror plate 7 may be any range as long as the wafer W inside does not come off. As described above, the drive unit 17A shown in FIG. 5 has a function of applying a Lorentz force (the driving force FY in FIG. 2) to the wafer W and the mirror plate 7 in the ± Y direction. It has a function of measuring the distance from the mirror plate 7 and a function of applying electrostatic attraction to the wafer W and the mirror plate 7 thereon. The last electrostatic attraction force can be said to be a holding force for holding the position (height) of the wafer in the Z direction at a desired position by a combination with a floating force by compressed air. These three functions also include all the other drive units 17A and 17AR shown in FIG. However, regarding the Lorentz force, since the drive unit 17AR is rotated by 90 ° with respect to the drive unit 17A, the direction of the Lorentz force (drive force FX) generated by the drive unit 17AR is the ± X direction.
In this example, these Lorentz forces are combined to displace the wafer W and the mirror plate 7 by a desired amount in the X direction and the Y direction with respect to the drive base 4 and to move the wafer W
Then, the mirror plate 7 is rotated by a desired angle.

At this time, the coordinates in the X and Y directions and the rotation angle of the wafer W are obtained from the measured values of the laser interferometers 8X, 8YA and 8YB and the measured values of the displacement meters 31A to 31E. The main control system 9 includes the drive units 1
The controller (eg, the controller 23 in FIG. 5) in the drive circuit of each of the 7A and 17AR is given a command as to how much the wafer W is displaced in each part, and the controller 23 and the like respond in response to the command. A predetermined Lorentz force is generated in the driving unit 17A or the like. The distance from the upper plate 32 of the drive base 4 to the bottom surface of the wafer W and the mirror plate 7 detected by the gap detection circuit (eg, the gap detection circuit 26 in FIG. 5) in the drive circuits of the drive units 17A and 17AR is as follows.
It is supplied to the main control system 9 via the corresponding control unit 23 and the like,
The main control system 9 outputs a target value of the interval to the control unit 23 and the like based on these intervals, and accordingly, in each of the drive units 17A and 17AR, the intervals between the wafer W and the mirror plate 7 are designated. Set the target value.

Next, an example of the operation when exposing the wafer W by the projection exposure apparatus of this embodiment will be described. First, in FIG. 1, when a wafer W is supplied from a wafer loader system (not shown) into the mirror plate 7 on the drive base 4, the main control system 9 transmits a predetermined standard value via the flow rate adjusting valve 14. Many air supply holes 1 of the drive base 4 at the flow rate
Compressed air is blown from 3A and 13AR. As a result, the wafer W and the mirror plate 7 float above the drive base 4 and are held. Thereafter, the main control system 9 performs, for example, the bending correction of the wafer W.

FIG. 7 is a schematic sectional view of the drive base 4. In FIG. 7, three drive units (in FIG. 7, drive units 17B, 17E, 17
H), and the wafer W is floating above the drive base 4 by the compressed air. However, the wafer W has a curve, and the two-dot chain line 53 simply floats.
It is assumed that the outer peripheral part is lowered as shown by. In this case, the main control system 9 of FIG.
Since the bend of the wafer W can be recognized from the measured value of the interval at R, the amount of compressed air blown to the bottom surface of the wafer W via the flow control valve 14 is increased, and the levitation force on the wafer W is increased. Further, the main control system 9 includes the drive units 1
A command is issued to the control units (the control unit 23 and the like) of the 7A and 17AR to make the distance to the wafer W the same. As a result, in the center drive unit 17E of FIG. 7, the electrostatic attraction force is increased to maintain the distance δE to the wafer W at the target value, and at the both end drive units 17B and 17H, the electrostatic attraction force is reduced. By extending the distances δB and δH to the wafer W to the target values, the distances δB, δE, and δH eventually become the target values. Similarly, in the other drive units 17A and 17AR, equal intervals are set, and the curvature of the wafer W is corrected.

Next, with the wafer W floating, the wafer W
Is at a predetermined reference position with respect to the drive base 4,
The alignment coordinates of each shot area are obtained by detecting the position of the alignment mark of each shot area on the wafer W using an alignment sensor (not shown). Thereby, the positional relationship between the projected image of the reticle R and each shot area of the wafer W is obtained based on the measurement values of the laser interferometers 8X, 8YA, 8YB and the displacement meters 31A to 31E. In addition, by controlling the distance between the drive units 17A and 17AR, the auto-focusing of the wafer W,
Also, automatic leveling (tilt angle correction) is performed. In this state, the wafer W and the mirror plate 7 are stepped through the drive base 4 in a non-contact manner so that the shot area to be exposed on the wafer W is positioned in the exposure field of the projection optical system 3 and the reticle R The pattern image is exposed.

As described above, the wafer W is driven through the drive base 4.
When the mirror plate 7 is driven in a non-contact manner, the respective drive units 17A and 17AR are used, for example, as shown in FIG. That is, when correcting the shift amount of the rotation angle (the clockwise shift amount), the main control system 9 sets the two X-axis positions at the bottom of the wafer W as shown in FIG. Driving unit 17AR and two Y-axis driving units 17A
Is supplied to such a control unit as to offset the shift amount. Accordingly, the right drive unit 17A, the upper drive unit 17AR, and the left drive unit 17A
A, and the Lorentz forces F1, F2,-in the counterclockwise direction on the wafer W from the lower drive unit 17AR.
F1 and -F2 act to rotate the wafer W counterclockwise. At this time, since the rotation angle of the wafer W is monitored from the measurement values of the laser interferometers 8YA and 8YB and the displacement meters 31D and 31E in FIG. 2, the rotation angle of the wafer W is accurately corrected in a closed loop based on this. Is done.

Next, when the wafer W is displaced in the −X direction, the main control system 9 controls the control unit of the plurality of X-axis drive units 17AR at the bottom of the wafer W as shown in FIG. , A command is issued to generate a Lorentz force in the −X direction. In response to this, Lorentz force F3 in the −X direction acts on wafer W from drive unit 17AR, and wafer W is displaced in the −X direction. Similarly, when the wafer W is displaced in the −Y direction, FIG.
As shown in (c), the main control system 9 issues a command to the control units of the plurality of Y-axis drive units 17A at the bottom of the wafer W to generate a Lorentz force in the −Y direction.
In response to this, the Lorentz force F4 in the −Y direction acts on the wafer W from the drive unit 17A, and the wafer W is displaced in the −Y direction. At this time, X of wafer W
Direction, Y direction position is the laser interferometer 8X, 8YA, 8Y
B and the displacement gauges 31A to 31E are monitored with high accuracy, so that the position of the wafer W is accurately corrected in a closed loop based on this.

As described above, in this embodiment, since the wafer W is driven without contact, the wafer W can be positioned at a high speed. Therefore, the throughput (productivity) of the exposure process is increased. In addition, the drive base 4 only needs to drive the wafer W and the mirror plate 7 and generates a small amount of heat.
Since the wafer W is floating from the drive base 4, the influence of heat generated by the drive base 4 is hardly transmitted to the wafer W, and the positioning accuracy of the wafer W is improved.

Further, the wafer W is placed on the drive base 4 of this embodiment.
Are held in a non-contact manner, so that even if foreign matter such as a resist residue adheres to the back surface of the wafer W, the wafer W does not bend, and the curvature of the wafer W is controlled by the drive units 17A and 17AR. Since the correction can be made by controlling the electrostatic suction force, the wafer W during exposure is held in a flat state. Further, there is no generation of foreign matter due to contact with the wafer. Therefore, the reticle image can be transferred to each shot area of the wafer W at a high resolution, thereby improving the yield of the finally manufactured semiconductor integrated circuit.

In this embodiment, the driving units 17A, 17
Since each of the ARs can individually control the electrostatic attraction force on the wafer W and can separately measure the distance to the wafer W, even when the wafer W has local deformation,
By controlling the electrostatic attraction force of the drive unit at the bottom of that portion, local deformation can be easily corrected. This is particularly effective when exposing a large wafer where local deformation is likely to occur.

In the above embodiment, since the driving force generating electrodes 18A and 18B are also used as gap sensors for measuring the distance to the back surface of the wafer W, the configuration is simplified. An independent gap sensor may be provided. Furthermore, in this example, the wafer W
Is provided with a focus position detection system (not shown) for detecting the position of the front surface of the wafer W in the Z direction. The distance from the base 4 may be controlled.

Next, a second embodiment of the present invention will be described with reference to FIGS. In the above-described embodiment, the position of the wafer W is indirectly measured via the mirror plate 7, whereas in the present embodiment, the position of the wafer W is directly measured and only the wafer is driven. 9 and FIG.
In FIG. 0, portions corresponding to FIGS. 2 and 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 9 is a plan view of the drive base 4A of this embodiment. In FIG. 9, the drive unit 1 has a pitch PX in the X direction and a pitch PY in the Y direction.
7A and 17AR are alternately arranged. The configuration of the drive units 17A and 17AR is substantially the same as that of the first embodiment, and the air supply holes 13 in the drive units 17A and 17AR are provided.
Compressed air is blown out from A and 13AR, respectively, and the wafer W is floated by the compressed air. Thus, in this example, the wafer W is floating alone on the drive base 4A. In addition, the drive units 17A and 17AR generate an electrostatic attraction force on the wafer W, respectively, and can maintain a desired distance to the wafer W without contact. Further, the driving units 17A and 17AR generate a driving force (Lorentz force) FY and a driving force (Lorentz force) FX in the Y direction and the X direction with respect to the wafer W in a non-contact manner, respectively. , FX, the wafer W is moved and rotated in the X and Y directions.

The mechanism for measuring the position of the wafer W in the XY plane in this embodiment is also incorporated in the drive units 17A and 17AR. FIG. 10 typically shows a cross-sectional view of one drive unit 17A. In FIG. 10, the drive circuit of drive unit 17A is substantially the same as drive circuit 22A of FIG.
10 except that the gap detection circuit 16 of FIG.
Is replaced by a gap position detection circuit 26A. The gap position detecting circuit 26A also supplies an AC voltage VA3 having a high frequency f2 to the electrodes 18A and 18B of the driving unit 17A via the synthesizing circuit 27, so that the upper plate 32 of the driving base 4A and the bottom surface of the wafer W , The capacitance C of the capacitor formed according to the interval is detected. Then, in a state where the wafer W is on the drive unit 17A, that is, in a state where the capacitance C is slightly deviated from a predetermined reference value, the gap position detection circuit 26A detects an interval from the change in the capacitance C to the wafer W, Figure 5 shows the detection results.
Is supplied to the control unit 23.

On the other hand, when the wafer W moves in the X direction and the edge portion 33 of the wafer W crosses over the electrodes 18A and 18B, the capacitance C detected by the gap position detection circuit 26A greatly changes. Therefore, the gap position detecting circuit 26A detects the edge portion 3 of the wafer W from the change in the capacitance C.
3 in the X direction (the reference point is, for example, the electrode 18
A, 18B) and supplies the detection result to the main control system 9 via the control unit 23 in FIG. And FIG.
In the main control system 9, the X and Y directions of the wafer W are obtained from the positional deviation amounts in the X and Y directions of the edge portion of the wafer W detected by the gap position detection circuit 26A attached to each of the drive units 17A and 17AR. The position in the direction and the rotation angle are calculated, and the drive units 17A and 17
The wafer W is positioned in a non-contact manner through the AR. Other configurations are the same as those of the first embodiment.

As described above, in this embodiment, the drive units 17A,
Since the electrodes 18A to 18D of the 17AR are also used as capacitance type edge sensors, the displacement including the expansion and contraction of the wafer W is detected in a non-contact manner.
Position control by itself is possible. Next, a third embodiment of the present invention will be described with reference to FIG. In the above-described embodiment, the wafer is floated by blowing the compressed air to the back surface of the wafer, whereas in the present embodiment, the wafer (or the holder) is sucked upward and floated. In FIG. 7, the same reference numerals are given to the portions corresponding to FIGS. 1 to 3 and the detailed description thereof is omitted.

FIG. 11 shows a part of the projection exposure apparatus of this embodiment. In FIG. 11, the drive unit 17 is provided at a predetermined pitch in the X and Y directions on the bottom of the upper plate 32 of the drive base 4B.
A and 17AR are alternately arranged. However, in this example, the drive units 17A and 17AR are not arranged in the area 32a of a predetermined size including the exposure field of the projection optical system 3. In addition, the drive units 17A, 17A of this example
The configuration of R is almost the same as that of the drive unit 17A of FIG. 5, but further has a function of detecting the displacement of the edge of the moving body that crosses the upper part as in the example of FIG. However, since the drive units 17A and 17AR of the present example do not need to blow out compressed air for floating the wafer W, the air supply source 15, the flow control valve 14, and the air supply pipe 16 of FIG. 2 are not provided.

A substantially rectangular plate-like movable plate 34 floats on the drive base 4B.
The wafer W is placed in the recess 34a on the upper surface of the wafer W. The movable plate 34 is made of an electric conductor made of, for example, a metal plate or a conductive ceramic. In this example, the movable plate 34 is connected to the drive units 17A, 17 in the drive base 4B.
It is driven in a non-contact manner in the XY plane by the AR. At this time, the displacement of the edge of the movable plate 34 is also detected by the edge displacement detection function of the drive units 17A and 17AR, and the movable plate 34 is positioned based on the detection result.

As described above, the movable plate 34 and the wafer W
11 is fixed to the lower side surface of the projection optical system 3 in FIG. 11 and has a bottom surface that covers most of the area where the movable plate 34 moves. Are fixed at a predetermined pitch in the Y direction. For example, the suction electrode pair 36A has two elongated electrodes arranged in the Y direction at predetermined intervals in the Y direction. It is configured.
A predetermined DC voltage is applied to the suction electrode pairs 36A, 36B, 36C,... From a power supply in a main control system (not shown), and thereby, the suction electrode pairs 36A, 36B, 36
An electrostatic attraction force is generated between C,... And the movable plate 34 and the wafer W, and the movable plate 34 and the wafer W are sucked upward (in the + Z direction) and float. At this time, an electrostatic attraction force is also generated between the wafer W and the movable plate 34, and the wafer W is held in the concave portion 34a of the movable plate 34 by the electrostatic attraction force. Other configurations are the same as those of the projection exposure apparatus of FIG.

In this embodiment, since the movable plate 34 and the wafer W are lifted toward the mounting frame 35 by electrostatic attraction, each drive unit 17 in the drive base 4B is moved.
By controlling the electrostatic attraction force in the -Z direction by the A and 17AR, the height and the inclination angle of the movable plate 34 can be controlled to desired states. However, since no electrode pair for suction is provided in the area through which the exposure light from the projection optical system 3 passes,
If no measures are taken, the movable plate 3
4 and the wafer W may be bent downward. Therefore, in the suction electrode pair disposed in the vicinity of the exposure field of the projection optical system 3 in the suction electrode pair 36A, 36B, 36C,... Of the present example, the central wafer W and the movable plate in the exposure field are used. A moment (= distance to the center × force) is applied to the wafer W and the movable plate 34 so as to lift the wafer 34 upward. Thus, the wafer W is always kept flat.

In this example, the area 32a near the exposure field by the projection optical system 3 in the drive base 4B is
Although the drive units 17A and 17AR are not provided,
Since the area around the bottom surface of the movable plate 34 is always above one of the drive units 17A and 17AR, the wafer W can always be positioned at high speed and with high precision via the movable plate 34. As described above, the driving unit 1 is located in a predetermined range including the exposure field, that is, near the lower surface of the wafer W.
In the configuration in which 7A and 17AR are not provided, since a device for generating a fluctuating magnetic field and a magnetic material are not disposed near the lower surface of the wafer W, even if exposure is performed using an electron beam, the The orbit does not change. Therefore, FIG.
The non-contact driving mechanism having the above configuration is also suitable for an electron beam exposure apparatus.

In the above embodiment, the present invention is applied to a batch exposure type projection exposure apparatus. However, the present invention scans and transfers a reticle and a wafer in synchronization with a projection optical system. May be applied to a scanning exposure type projection exposure apparatus such as a step-and-scan method, and may be applied to a proximity type exposure apparatus. Further, the positioning device of the present invention is not limited to an exposure device, and can be applied to other devices such as a machine tool. As described above, the present invention is not limited to the above-described embodiment, and can take various configurations without departing from the gist of the present invention.

[0062]

According to the first positioning device of the present invention,
A flat object (such as a semiconductor wafer) and a flat holding body are levitated on a base, and a driving force such as Lorentz force is generated for the levitated driven body to perform non-contact positioning. Therefore, since the driven body can be reduced in size and weight, there is an advantage that positioning of the flat object can be performed at high speed and with high accuracy by using a small-sized apparatus with a small amount of heat generation. Further, even if foreign matter or the like is present on the back surface of the flat object, the object does not contact the base, so that there is an advantage that the object is not distorted and no foreign matter is generated by the contact.

When the levitation device comprises an air supply device for ejecting compressed gas from an opening formed in the base, the levitation force can be applied to the bottom surface of the driven body in a substantially constant state at all times. When the levitation device includes a plate-shaped object and a pair of suction electrodes arranged above the plate-shaped holder, the configuration on the base side can be simplified. Also,
When the current generating section has a plurality of electrodes arranged on the surface of the base and applies a predetermined drive voltage between adjacent electrode pairs to cause a current to flow between regions facing the electrode pairs. Can generate current without contact. In addition, the magnetic field generator
When a magnetic field is provided between the adjacent electrode pairs, a magnetic field orthogonal to the current can be easily generated.

When measuring the distance from the surface of the current generating electrode to the back surface of the substrate based on the change in capacitance caused by the change in the distance from the surface to the substrate, a gap sensor or the like is separately required. There is no need to provide them, and the structure can be simplified. Further, a first displacement measuring device is a measuring device that is disposed facing a side surface of the flat holding member that is levitated by the floating device, and measures displacement at at least three places on the side surface of the flat holding member, A second displacement measuring device is arranged facing the outer peripheral surface of the flat object,
This is a measuring device for measuring displacement at least at three places on the outer peripheral surface of the flat object, and is further arranged to face the front or back surface of the flat holder and the flat object. When a height measuring device for measuring the distance to the front surface or the back surface of the object is provided, displacement of the flat object with six degrees of freedom can be easily measured.

In this case, when the first displacement measuring device is composed of laser interferometers each irradiating a measuring light beam to at least three positions on the side surface of the plate-like holding member levitated by the levitating device, the first non-contact measuring device is used. The displacement of the plate-like holder can be measured with high accuracy and in a wide range, and the second displacement measuring device detects the distance from the inner wall of the through hole of the plate-like holder to the outer peripheral surface of the plate-like object. When a plurality of gap sensors are used, the relative displacement of the flat object with respect to the flat holder can be easily measured with high accuracy.

In the case where the flat holding body and the suction force generating device for suctioning the flat object to the base side are further provided, the positioning of the flat object in the height direction can be performed with high accuracy. it can. In this case, when the attraction force generating device applies a predetermined voltage between the pair of adjacent electrodes for generating the current to generate an electrostatic attraction force for attracting the plate-shaped object or the like to the base side, Can be used also as a current generator and a suction force generator, and the positioning of the flat object or the like in the height direction can be performed with an extremely simple configuration.

Further, when the applied voltage between the current generating electrode pair is adjusted for each set to correct the distortion of the flat object, the flat object can be flattened without increasing the size of the apparatus. The degree can be improved. Further, according to the second positioning apparatus of the present invention, since only the flat object (semiconductor wafer or the like) is driven in a non-contact manner by Lorentz force, the driven body is minimized and lightest, and extremely high speed is achieved. In addition, the positioning of the flat object can be performed with high accuracy.

According to the exposure apparatus of the present invention, the positioning of the semiconductor wafer is performed at high speed in a non-contact manner by using the positioning apparatus of the present invention, so that the throughput of the exposure step can be increased. Further, since the semiconductor wafer is not distorted due to the foreign matter on the back surface of the semiconductor wafer and no foreign matter is generated due to contact with the semiconductor wafer, the yield of the manufactured semiconductor integrated circuit and the like can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a projection exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a driving base 4, a mirror plate 7, and the like in FIG. 1;

FIG. 3 is a sectional view taken along the line AA in FIG. 2;

FIG. 4 is an enlarged view of a part of FIG. 3;

FIG. 5 shows a drive unit 17 used in the embodiment.
FIG. 2A is a diagram showing the driving circuit.

FIG. 6 is a cross-sectional view for explaining the operation of the drive unit 17A.

FIG. 7 is a cross-sectional view for explaining a case in which the bending of the wafer W is corrected using the drive unit.

FIG. 8 is an explanatory diagram in the case where the rotation of the wafer W and the driving in the X direction and the Y direction are performed using the driving unit.

FIG. 9 is a plan view showing a drive base 4A of a projection exposure apparatus according to a second embodiment of the present invention.

FIG. 10 is a sectional view showing a drive unit 17A used in the second embodiment.

FIG. 11 is a sectional view showing a main part of a projection exposure apparatus according to a third embodiment of the present invention.

FIG. 12 is a configuration diagram illustrating an example of a wafer stage of a conventional exposure apparatus.

[Explanation of symbols]

 R Reticle 3 Projection optical system W Wafer 4, 4A, 4B Drive base 7 Mirror plate 8X, 8YA, 8YB Laser interferometer 9 Main control system 13A, 13AR Air supply hole 15 Air supply source 17A, 17AR Drive unit 18A to 18D Electrode 19 Iron core Reference Signs List 20 coil 22A drive circuit 24 electrostatic attraction circuit 25 AC voltage generation circuit 26 gap detection circuit 28 excitation circuit 31A to 31E capacitance type displacement meter 34 movable plate 36A, 36B, 36C suction electrode pair

Claims (15)

[Claims] 1. A positioning device for positioning a flat object made of an electric conductor on a predetermined base, comprising a substantially rectangular electric conductor, and having a central portion in which the flat object is stored. A flat holding member having a hole, a floating device for floating the flat object and the flat holding member on the base, a current generator for inducing a current in the flat object and the flat holding member, and A magnetic field generator that generates a magnetic field in a direction that intersects the current induced by the current generator,
A driving force consisting of a Lorentz force is generated on the flat object and the flat holding member in a direction orthogonal to the current and the magnetic field, and the generated driving force causes the flat object and the flat holding member to move from the base to the base plate. A driving device that moves along the surface; a first displacement measuring device that measures the displacement of the plate-like holding member; and a second displacement measuring device that measures the displacement of the plate-like object with respect to the plate-like holding member. And moving the flat holding body and the flat object via the driving device based on the measurement results of the first and second displacement measuring devices, and positioning the flat object in a non-contact state. A positioning device. 2. The positioning device according to claim 1, wherein said levitation device comprises an air supply device for ejecting compressed gas from an opening formed in a surface of said base. 3. The positioning device according to claim 1, wherein the levitation device includes a pair of suction electrodes disposed above the flat object and the flat holding member, respectively. Wherein a predetermined voltage is applied to the plate-like object and the plate-like holding body to levitate by electrostatic attraction. 4. The positioning device according to claim 1, 2 or 3, wherein the current generator has a plurality of electrodes arranged on a surface of the base, and a predetermined current is provided between adjacent pairs of electrodes. And a current flowing between the plate-like object and the region on the plate-like holding member facing the electrode pair by applying the driving voltage of (i). 5. The positioning device according to claim 1, wherein the magnetic field generator is made of a magnetic body provided in the base. 6. The positioning device according to claim 1, wherein a distance from a surface of the electrode of the current generating portion to a back surface of the flat holding body and the flat holding object is changed. Further comprising a capacitance detection device for detecting a change in the generated capacitance,
A positioning device for measuring a distance to the back surface of the flat holding body and the flat object based on a detection result of the capacitance detecting device. 7. The positioning device according to claim 1, wherein the first displacement measuring device faces a side surface of the flat holding member that is levitated by the levitating device. A measuring device arranged to measure displacement at at least three places on the side surface of the flat holding member, wherein the second displacement measuring device is arranged facing an outer peripheral surface of the flat object; A measurement device for measuring displacement at at least three points on an outer peripheral surface of an object, further disposed to face the front or back surface of the plate-shaped holder and the plate-shaped object, and the surface of the plate-shaped holder and the plate-shaped object Or a positioning device comprising a height measuring device for measuring an interval to a back surface. 8. The positioning device according to claim 7, wherein the first displacement measuring device applies a measuring light beam to at least three places on a side surface of the flat holding member that is floated by the floating device. A positioning device comprising a laser interferometer for irradiating, and measuring a displacement of the flat holding member based on a detection value of the laser interferometer. 9. The positioning device according to claim 7, wherein the second displacement measuring device detects a distance from an inner wall of a through hole of the flat holding member to an outer peripheral surface of the flat object. A plurality of gap sensors for measuring a displacement of the flat object with respect to the flat holding body based on detection values of the plurality of gap sensors. 10. The positioning device according to claim 1, further comprising: a suction force generating device that suctions the flat holding body and the flat object toward the base. Characteristic positioning device. 11. The positioning device according to claim 10, wherein the attraction force generating device applies a predetermined voltage between adjacent pairs of electrodes of the current generating unit, and the flat holding body and the flat object are applied. A positioning device for generating an electrostatic attraction force for attracting an object to a base side. 12. The positioning device according to claim 11, wherein a voltage applied between adjacent electrode pairs of the current generator is adjusted for each set to correct the distortion of the flat object. Positioning device. 13. A positioning device for positioning a flat object made of an electric conductor on a predetermined base, wherein the floating device floats the flat object on the base, and a current is applied to the flat object. And a magnetic field generator for generating a magnetic field in a direction intersecting the current induced by the current generator, and Lorentz in the direction perpendicular to the current and the magnetic field with respect to the flat object. A driving device that generates a driving force composed of a force and moves the flat object along the base surface by the generated driving force, and a measuring device that measures a relative position of the flat object with respect to the base. And positioning the flat object in a non-contact state via the driving device based on the position of the flat object measured by the measuring device. Positioning device. 14. The positioning device according to claim 13, wherein the measuring device has a plurality of electrodes arranged on a surface of the base, and a back surface of the flat object and the plurality of electrodes. A position of the flat object is measured based on a change in capacitance generated during the positioning. 15. An exposure apparatus comprising: the positioning device according to claim 1; and exposing a mask pattern image on a semiconductor wafer positioned by the positioning device.