JPS62192685A - Position controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a position control device, and in particular to positioning of an alignment stage on which a wafer, etc. is placed when printing a circuit pattern on the wafer in a semiconductor exposure device or the like. The present invention relates to a device for carrying out.

[Background of the Invention] Conventionally, in a micro-positioning device for a wafer stage in a semiconductor exposure apparatus, etc., as shown in FIG. , a configuration in which a preload is applied by a spring 3 or the like to enable reciprocating motion has been used. Two sets of rod clamping piezoelectric elements 4.5 and 8, 9 for driving the rod 2, and a driving piezoelectric element 6 for driving the rod 2 in the movement direction of the stage 1.
7 was used. Such microstep driving by each piezoelectric element can be performed, for example, in a state in which the piezoelectric element 8.9 is extended and the rod 2 is clamped, the piezoelectric elements 6 and 7 are expanded and contracted, and the pressure τ element 6.7 is expanded and contracted. The clamping piezoelectric element 4.5 is extended to clamp the rod 2.

In this state, the rod 2 is driven in either direction by releasing the clamp by the piezoelectric elements 8 and 9 and contracting or expanding the drive piezoelectric elements 6 and 7 in the opposite direction. Thereafter, the rod 2 is again clamped by the piezoelectric element 8.9 and the clamp by the piezoelectric element 4.5 is released, and the same operation as described above is repeated, whereby the rod 2 is displaced by a minute distance, and the stage 1 is similarly displaced. Displace. In this way, the stage 1 is positioned by performing microstep driving a desired number of times.

However, in the conventional type described above, if the preload by the spring 3 is increased, the amount of movement per drive step changes or the clamp part slips, so it is impossible to increase the preload too much. . For this reason, the natural frequency of the movable parts including the stage and the rod in the driving direction decreases, resulting in the inconvenience that high-speed microstep driving cannot be performed.

Furthermore, in conventional drive methods, the amount of movement per one drive step is constant, so in order to increase the resolution of positioning, it is necessary to reduce the amount of movement per one step, and increasing the resolution increases the feed rate. There was an inconvenience that it decreased.

[Object of the Invention] In view of the problems with the conventional type described above, the present invention enables high-speed and high-precision positioning with a simple configuration in a position control device, and also firmly clamps and drives the stage body after positioning. The purpose is to increase the rigidity in the direction and eliminate the adverse effects such as positional fluctuations due to disturbances such as external vibrations.

[Summary of the Invention] In order to achieve the above-mentioned object, the present invention uses a clamping actuator in addition to a driving actuator that drives the movable stage, and this clamping actuator is mechanically connected to the stage itself or the stage body. configured to clamp a portion secured to the. This enables high-speed and highly accurate positioning.

[Explanation of Examples] Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 schematically shows a position control device according to an embodiment of the present invention. The apparatus shown in the figure includes a stage 11.on which a semiconductor wafer, etc. is placed. Guide 1 that determines the movement of the stage 11
2a, 12b, a base 13, a stage driving piezoelectric element 14 whose one end is fixed to the stage 11, a clamped member 15 connected to the other end of the piezoelectric element 14, a clamper 16a1 that clamps one end of the stage driving piezoelectric element 14. A piezoelectric element 16b for driving the clamper 16a is provided.

Furthermore, the apparatus of FIG.
Clamper 17a and clamper 1 that clamp l itself
The driving piezoelectric element 17b of 7a is provided. In addition, the first
In the illustrated embodiment, two sets of clampers 17a for clamping the stage 11 and their piezoelectric elements 17b are provided.

FIG. 2 shows a position control device according to another embodiment of the present invention applied to a rotary stage. The device shown in the figure includes a rotating stage 21, a bearing 22 that guides the rotational movement of the stage 21, a base 23, a piezoelectric element 24 for driving the stage whose one end is fixed to the stage 21, and a piezoelectric element 24.
Clamped member 25 and piezoelectric element 24 connected to the other end
A clamper 26a1 clamps one end of the clamper 26a.
driving piezoelectric element 26b.

It has a clamper 27a for clamping the stage 21 and a piezoelectric element 27b for driving the clamper 27a. Note that three sets of clampers 27a and piezoelectric elements 27b are each provided around the stage 21.

Further, reference numeral 28 is a shaft that projects from the base 23 and is fixed to the inner ring of the bearing 22.

Next, the operation of the apparatus of each of the above embodiments will be explained with reference to FIG. As shown in FIG. 3(a), for example, a high level voltage is applied to the piezoelectric elements iab, 2ab in FIG. 1 or 2 to operate the clampers 16a, 26a, respectively, and the piezoelectric elements 14. Fix one end of 24. In this state, the stage driving piezoelectric element 14.2
When a voltage is applied to 4, each piezoelectric element expands by a length L, for example, and displaces each stage 11.degree. 21. Next, the piezoelectric elements 17b and 27b for stage clamping are operated to fix each stage N and 21, and then the piezoelectric elements 16b and 2
6b is removed. By repeating such operations, each stage 11.21 becomes a piezoelectric element 14.24.
The extension of M fl will be microstep driven.

In this case, as shown in FIG. 3(b), by adjusting the voltage applied to the stage driving piezoelectric element 14.24 and adjusting the elongation amount 1' according to the applied voltage, the unit transverse movement amount described above can be adjusted. Fine adjustment below p is possible.

FIG. 4 shows a control procedure for high-speed and highly accurate positioning by combining the microstep drive shown in FIG. 3(a) and the expansion/contraction control drive of the piezoelectric element shown in FIG. 3(b). shows. That is, as shown in FIG. 4, first, target position information is referred to and it is determined whether the difference between the current position and the target position is shorter than the amount of expansion l of the piezoelectric element. If the distance difference between the target position and the current position is larger than the extension amount λ, microstep driving is performed.

If this distance difference is shorter than the amount of extension, a voltage corresponding to the distance difference is applied to the piezoelectric element to reach the target position. In this case, the voltage applied to the piezoelectric element is gradually increased, for example, and when it is detected that the stage has reached the target position, the voltage increase is stopped.

In order to perform position control as shown in FIG. 4, a position control system as shown in FIG. 5, for example, is used. The system shown in the figure further includes a stage 1 in addition to the apparatus shown in Fig. 1.
A sensor 51 for detecting the position of point 1, an amplifier 52, a controller 53, a driver 54, and a power source 55 are added. In the system shown in FIG. 5, control as shown in FIG. 4 is performed by configuring a feedback system including a sensor 51, a controller 53, and the like. In this case, the controller 53 determines whether the difference between the target position and the current position of the stage 11 is determined by the piezoelectric element 1 according to the output of the sensor 51.
Determine whether it is larger or smaller than the maximum unit elongation amount in 4.
As described above, it is determined whether the drive is microstep drive or expansion/contraction amount control drive, and a signal corresponding to each control method is supplied to the driver 54.

[Effects of the Invention] As described above, according to the present invention, by providing a clamper that directly clamps the stage, a position control device that does not require preloading and has high rigidity in the driving direction can be obtained. In addition, by using both microstep drive capable of high-speed drive and piezoelectric element expansion/contraction drive capable of minute positioning, it becomes possible to perform high-speed and highly accurate positioning.

[Brief explanation of drawings]

1 and 2 are perspective views showing a position control device according to an embodiment of the present invention, and FIGS. 3(a) and 3(b) respectively.
4 is a waveform diagram for explaining the operation of the position control device according to the present invention, FIG. 4 is a flowchart showing the operating principle of the position control system using the device of FIG. 1 or 2, and FIG.
This figure is a schematic block circuit diagram showing a specific configuration of a position control system for performing the operation shown in FIG. 4, and FIG. 6 is an explanatory diagram showing a conventional position control device. 1, 11.21: Stage, 2: Rod, 3; Spring, 4.5.・・・・・・・・・9. Piezoelectric element, 12a, !
2b guide, 13.23: base, 14, 16b, 17b, 24.26b, 27b
: Piezoelectric element, 15a, 17a, 26a, 27a
: Clamper, 15.25: Clamped member, 22: Bearing, 28: Shaft. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Tetsuya Ito +7b 15 Figure 5 Figure 6

Claims (1)

[Claims] 1. A movable stage, a driving actuator that mechanically displaces the movable stage, and one or more clampers that fix the movable stage at least after the movable stage is positioned by the driving actuator. A position control device comprising: 2. Using a piezoelectric element as the drive actuator,
2. The apparatus according to claim 1, wherein one end of the piezoelectric element is fixed to the movable stage, and the other end can be selectively fixed or released by a separately provided clamper.