JPH11186156A - Xy stage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable stable fine positioning operation at a high speed, by installing electromagnets for levitation which levitates and retains a stage, and a linear motor stator which positions the stage in the XY direction in a noncontact manner. SOLUTION: Four corners of an upper plate 11a on which a specimen is mounted and a lower plate 11b are combined by struts 11c, and an XY stage 11 is constituted. On the upper surface of the upper plate 11a, e.g. a semiconductor wafer 12 is mounted. Electromagnets 14 for levitation are arranged on four corners of the lower surface of a fixed pedestal 13. Magnetic pole surfaces of the electromagnets face the lower plate 11b of the stage 11 and levitate and retain the stage 11 in a noncontact manner. A stator 15a of a linear motor is installed in the upper surface of the fixed pedestal 13, and a movable member for the linear motor is installed on the lower surface of the upper plate 11a of the stage 11. The movable member is constituted of a magnetic material having an uneven surface. The linear motor stator 15a of the fixed pedestal 13 exerts magnetic attractive force to a magnetic pole having the uneven surface in the X, Y directions, so that the stage 11 is moved and positioned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an XY stage, and particularly to a precise positioning suitable for mounting a sample such as a semiconductor manufacturing apparatus such as a drawing apparatus for optical lithography or a semiconductor inspection apparatus. XY stage capable of performing the following.

[0002]

2. Description of the Related Art In a semiconductor manufacturing apparatus, an inspection apparatus, or the like, a sample is usually mounted on an XY stage to perform processing, observation, and the like. In recent years, as semiconductor devices have become highly integrated, circuit wiring has become finer, and the distance between wirings has been decreasing. In particular, in the case of optical lithography of 0.5 μm or less, it is necessary to position the imaging point of the stepper with high accuracy.

However, in the conventional XY stage, a table on which a sample is placed is positioned by feedback control in an X direction or a Y direction through a ball screw or the like by an actuator, for example, a servomotor placed on a mounting table. Was controlled. Thus, a mechanism having mechanical friction is not always sufficient for high-speed and high-accuracy alignment.

[0004]

For example, in the case of a scan type stepper, it is necessary to move the XY stage smoothly at high speed, with high precision, and smoothly. As described above, in a semiconductor manufacturing apparatus and the like, there is an increasing demand for a high-speed and high-precision positioning of a mounted object such as an object to be measured and an object to be processed on an XY stage. The same applies to electron microscopes, and it is desired that positioning on the order of submicrons can be performed accurately and at high speed.

The present invention has been made in view of the above circumstances, and has as its object to provide an XY stage capable of performing a fine positioning operation stably and at a high speed.

[0006]

According to the present invention, there is provided an XY stage comprising an upper plate on which a load is placed, a lower plate, and a column connecting four corners of the upper plate and the lower plate. A levitation electromagnet having a magnetic pole surface facing the lower plate for levitation and supporting the stage; and an XY stage facing the mover of the linear motor provided on the lower surface of the upper plate.
And a linear motor stator positioned in a non-contact manner in the direction.

According to the present invention described above, the stage on which the object is mounted is levitated and supported by the levitating electromagnet, and the positioning operation in the XY directions is similarly performed without contact by the linear motor. The positioning operation of the load on the stage can be performed. This makes it possible to stably perform high-magnification observation in an electron microscope or the like, and to perform fine alignment with high accuracy in a semiconductor manufacturing apparatus or the like. Therefore, a favorable effect can be brought about, for example, on the production yield of semiconductor products.

[0008] Further, there is provided a displacement sensor for detecting a relative displacement between the stage lower plate and the levitation electromagnet, and a control circuit for controlling a magnetic force of the levitation electromagnet based on a signal from the displacement sensor. I do. As a result, feedback control becomes possible, and the stage can be positioned at the target floating position in the Z direction or the like.

[0009] Further, there is provided a position sensor for detecting a position of the stage in the X and Y directions, and a control circuit for driving the linear motor and positioning the stage based on a signal from the position sensor. . This also enables highly accurate positioning in the X and Y directions and the like.

The levitation electromagnet and the linear motor are each sealed by a partition. Accordingly, it can be used even under a high cleanliness atmosphere such as a vacuum.

[0011]

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

FIG. 1 shows an XY stage according to an embodiment of the present invention. In the XY stage 11, an upper plate 11a on which a sample is placed and a lower plate 11b are connected to each other at four corners by pillars 11c. On the upper surface of the upper plate 11a, a load 12, such as a semiconductor wafer, is placed. stage
11 is floated and supported in a non-contact manner by an electromagnet of a fixed base 13 supported by a fixed leg 13a, and is similarly driven in a non-contact manner by a linear motor in the X and Y directions to perform positioning control.

FIG. 2 is an elevation view of the XY stage. On the lower surface of the fixed base 13, electromagnets 14
It has. The magnetic pole surface of the levitation electromagnet 14 faces the lower plate 11b of the stage 11, and applies a magnetic attractive force to the lower plate 11b, which is a magnetic plate, to support the stage 11 in a non-contact floating manner.

A displacement sensor is provided at a substantially central portion of each of the electromagnets 14, and a distance between the electromagnet 14 and the lower plate 11b made of a magnetic material plate is measured. As shown in FIG. , Α, β are controlled by exciting the levitation electromagnet 14 by a control circuit, and the lower plate 11b and, consequently, the entire stage 11 on which the load 12 is placed are levitated and supported at a predetermined target levitation position. .

As shown in FIG. 4, on the upper surface of the fixed base 13, a stator 15a of a linear motor is provided. A mover 15b for a linear motor is provided on the lower surface of the upper plate 11a of the stage 11.
It has. The mover 15b is made of, for example, a magnetic material having a comb-shaped uneven surface, and the linear motor stator 15a of the fixed base 13 is moved in the X direction and the Y direction in FIG. By applying magnetic attraction, the stage
Move 11 for positioning. As shown in FIG. 5, a laser interferometer 17a is provided on a base on which the fixed base 13 is fixed, and a mirror 17b for the laser
And the precise position is detected by the laser beam B. Therefore, the laser interferometer 17a is provided with the mirror 17b as shown in FIG.
By detecting the position signals in the Y and γ directions and controlling the primary side 15a of the linear motor by the control circuit as shown in FIG. 6, the stage 11 can be moved to the target position.

As a result, the stage 11 is levitated and supported by the magnetic attraction force of the levitating electromagnet 14 while the linear motor 15
By driving the stage 11 to an arbitrary position in the X and Y directions by a and 15b, positioning control can be performed in a non-contact manner. As described above, in the XY stage, since the positioning control is performed electromagnetically in a non-contact manner, a precise and high-speed positioning operation can be performed without using a mechanical mechanism such as a conventional gear.

In the XY stage, a fixed base 13, a motor stator (primary side) 15a, a floating electromagnet 1
4. The displacement sensors are sealed by cans. Therefore, by sealing these with a partition wall such as a can, it is possible to prevent contamination of a load requiring high cleanliness due to generation of gas or the like even in an environment with extremely high cleanliness such as a vacuum atmosphere. it can.

In the above description, the lower plate 11 of the stage 11 is moved by the floating electromagnet 14 provided on the lower surface of the fixed base.
b is suspended by magnetic attraction.
1b may be made of an aluminum plate or the like, and a magnetic pole surface of an electromagnet for generating an alternating magnetic field may be arranged below the aluminum plate to support repulsion and floating. Further, by disposing a metal plate such as an aluminum plate on the lower surface of the upper plate 11a, the movable member (secondary side) of the linear induction motor can be used.
a may be used as a stator (primary side) of the linear induction motor to drive the linear induction motor.

Alternatively, the stage may be driven by a linear DC motor having a permanent magnet of a mover on the lower surface of the upper plate of the stage and a coil of the stator arranged on a fixed base 13.

Further, the stage may further include a support for mounting the object on the upper plate, and the movement of the support may be controlled by an actuator such as a piezoelectric element. Thus, rough positioning can be performed using a linear pulse motor, and fine positioning can be performed using an actuator such as a piezoelectric element. Thus, various modifications can be made without departing from the spirit of the present invention.

[0021]

As described above, according to the XY stage of the present invention, the stage is levitated and supported without contact.
Arbitrary positioning is possible in the X and Y directions. Therefore, it is possible to realize an XY stage with high accuracy and excellent high-speed response, thereby improving the throughput of equipment requiring fine positioning, such as a semiconductor manufacturing apparatus or an inspection equipment.

[Brief description of the drawings]

FIG. 1 is a perspective view of an XY stage according to an embodiment of the present invention.

FIG. 2 is an elevation view of the XY stage shown in FIG. 1;

FIG. 3 is a block diagram of a magnetic levitation control system.

FIG. 4 is a view showing a fixed base, (a) is a plan view,
(B) is AA 'sectional drawing of (a).

FIG. 5 is an explanatory diagram showing stage movement control.

FIG. 6 is a block diagram of a stage position control system using a linear motor.

FIG. 7 is a diagram showing a direction of movement of a stage.

[Explanation of symbols]

 Reference Signs List 11 Stage 11a Upper plate 11b Lower plate (magnetic material plate) 11c Column 12 Mount 13 Fixed base 14 Electromagnet for floating 15a Linear motor stator (primary side) 15b Linear motor mover (secondary side)

Claims (4)

[Claims] 1. A stage comprising an upper plate on which a load is placed, a lower plate, and a column connecting four corners of the upper plate and the lower plate, and a magnetic pole surface facing the lower plate of the stage. A floating electromagnet that levitates and supports the stage, and a linear motor stator that faces the mover of the linear motor provided on the lower surface of the upper plate and positions the stage in the XY directions in a non-contact manner. An XY stage characterized by the following. 2. The apparatus according to claim 1, further comprising: a displacement sensor for detecting a relative displacement between the stage lower plate and the levitation electromagnet; and a control circuit for controlling a magnetic force of the levitation electromagnet based on a signal from the displacement sensor. The XY stage according to claim 1, wherein 3. A position sensor for detecting a position of the stage in the X and Y directions, and a control circuit for driving the linear motor and positioning the stage based on a signal from the position sensor. The XY stage according to claim 1. 4. The XY stage according to claim 1, wherein each of the levitating electromagnet and the linear motor is sealed by a partition.