JPH0758338B2 - Flat object moving device - Google Patents

Description

The present invention relates to an exposure apparatus for forming a pattern on a flat object such as a semiconductor wafer or a liquid crystal display panel, or a moving apparatus for a flat object in various measuring devices. Regarding

[Prior Art] Conventional examples are shown in FIG. 3 and FIG. FIG. 4 is of FIG.
FIG. 1 is a wafer, 2 is a chuck for sucking the wafer 1, 3 is a Z stage for fixing the chuck 2, 4
Is an inner guide of the Z-direction guide, 5 is a steel ball, and 6 is an outer guide of the Z-direction guide. The inner guide 4, the steel balls 5, and the outer guide 6 form a Z-direction guide. Reference numeral 7 is a base for fixing the outer guide 6. 8 is a rotation stop plate fixed vertically to the Z stage 3, 16 is a bearing, and 17 is a bearing stand for supporting the bearing 16, which is fixed to the base 7. Reference numeral 18 is a spring hook A, which is fixed to the bearing base 17. A spring hook B is fixed to the rotation stop plate 8. Reference numeral 20 is a tension coil spring, and both ends thereof are respectively hooked on a spring hook A18 and a spring hook B19.

The elastic force of the spring 20 causes the bearing 16 to rotate the stopper plate 8
The Z stage 3 is pressed against and its degree of freedom in the θ direction is restricted. Reference numeral 14 denotes a piezo that expands and contracts in the Z direction, one end of which is fixed to the inner guide 4 of the Z direction guide and the other end of which is fixed to the reference plane. Reference numeral 15 is a driver for driving the piezo 14. With the above configuration, the wafer 1 can move in the Z direction without rotating in the θ direction.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, a moment acts on the Z stage 3 due to a frictional force generated between the detent plate 8 and the bearing 16, and the Z stage 3 moves together with the chuck 2 and the wafer 1 by an angle α. Lean. As a result, a positional deviation e was generated in the X direction, the parallelism between the reference surface and the wafer 1 was deteriorated, and the wafer 1 could not be moved with high accuracy.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and provides a moving device that prevents the Z stage on which a positioning object is mounted from tilting, and prevents displacement in the X direction and deviation of the parallelism of the mounting surface. With the goal.

[Means and Actions for Solving the Problems] In order to achieve the above object, according to the present invention, the Z stage 3
By providing means for restricting the θ direction with a frictionless bearing, the Z stage 3 can be driven straight without tilting along the Z axis (rotation axis). Also, θ
The θ rotation of the wafer 1 can be controlled by adjusting the direction regulation force.

[Embodiment] FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a view taken along the line AA of FIG. In the figure, 1 is a wafer, 2
Is a chuck for attracting the wafer 1, 3 is a Z stage for fixing the chuck 2, 4 is an inner guide of the Z direction guide, 5 is a steel ball, and 6 is an outer guide of the Z direction guide. Inner guide 4,
Z that doubles as a θ direction guide with the steel ball 5 and outer guide 6
It constitutes a direction guide. Reference numeral 7 denotes a base for fixing the outer guide 6, which is fixed to the reference surface. Reference numeral 8 is a rotation stop plate fixed vertically to the Z stage 3. 9,9 'are air bearings and 10,10' are air bearing housings. Reference numeral 14 denotes a piezo that expands and contracts in the Z direction, and one end (upper end) thereof is fixed to the lower end of the inner guide 4 of the Z direction guide, and the other end is fixed to the reference surface. Reference numeral 15 is a driver for driving the piezo. 11, 11 'are nipples for supplying air to the air bearings 9, 9', 12, 12 'are servo valves for adjusting the air pressure to the air bearings 9, 9', 13 is a control device, servo Control valves 12, 12 '. By controlling the servo valves 12 and 12 ', a constant pressure of air is sent to the air pads 9 and 9', respectively, and the air pressure holds the detent plate 8 from both sides in a non-contact manner. This restricts the degree of freedom of the Z stage 3 in the θ direction (rotation around the axis). At this time, the air pad 9,
Since there is no frictional force between 9'and the rotation stop plate 8,
No moment acts on the Z stage 3. Therefore, the Z stage 3 has the angle α shown in the prior art (FIG. 3).
The wafer surface moves along the axis of rotation (Z axis) without tilting and the wafer surface always moves up and down in parallel with the reference surface. This prevents the wafer 1 from being displaced in the X direction and can be moved in the Z direction with high accuracy while maintaining the parallelism with the reference plane.

In FIG. 2, reference numerals 21 and 21 ′ are displacement sensors fixed to the base 7. The sensors 21, 21 'measure the displacement of the sensor targets 22, 22' fixed to the Z stage 3. The rotation angle of the Z stage 3 can be detected by taking the difference between the outputs of the sensors 21, 21 '. The outputs of the sensors 21, 21 'are fed back to the control device 13, and the pressures of the air bearings 9, 9'are controlled via the servo valves 12, 12', respectively. This enables positioning control in the θ direction. Since air bearings have high rigidity by nature, highly accurate positioning is possible.

[Effects of the Invention] As described above, by using the non-contact air bearing as the rotation preventing means of the Z stage (restricting means in the θ direction), there is no friction with respect to the movement of the Z stage in the Z direction. The Z stage 3 can move extremely straight in the Z direction without the action of. As a result, the wafer 1 is not displaced in the X direction, for example, in a plane perpendicular to the Z direction, and deterioration of parallelism with the reference plane is prevented. This makes it possible to move the wafer with high accuracy. Further, displacement sensors 21, 21 'and sensor targets 22, 22' are provided so that the angle of the Z stage 3 in the θ direction can be detected.
By controlling the supply pressure to the air bearings 9 and 9'via the
Direction) can be positioned with high accuracy.

[Brief description of drawings]

1 is a cross-sectional view of a flat object positioning device according to an embodiment of the present invention taken along the rotation center axis, FIG. 2 is a view taken along the line AA of FIG. 1, and FIG. 3 is a rotation center axis of a conventional device. FIG. 4 is a sectional view taken along the line AA of FIG. 1: Wafer, 2: Chuck, 3: Z stage, 4: Inner guide, 5:
Steel ball, 6: Outer guide, 7: Base plate, 8: Non-rotating plate, 9,9 ': Air bearing, 12,12': Servo valve, 13: Control device, 14: Piezo, 16: Bearing, 21,21 ′: Displacement sensor, 22,22 ′: Sensor target.

Claims (3)

[Claims] 1. A stage which mounts a flat object to be positioned, is movable in the Z direction, and is rotatable in the θ direction around an axis parallel to the Z direction; and a stage for guiding the movement of the stage in the Z direction and θ. Rotation restraining means for preventing rotation in the direction, the rotation restraining means comprising a guide member fixed to the stage and a static pressure holding means for holding the guide member from both front and rear in the rotation direction in a non-contact manner. A flat-shaped object moving device characterized by. 2. The flat plate according to claim 1, wherein fine rotation adjustment in the θ direction is possible by separately controlling the static pressure acting on the front and rear of the guide member of the rotation restricting means. Object moving device. 3. The flat object moving device according to claim 2, wherein the static pressure holding means comprises an air bearing.