JPS5972135A - Super-precise x-y shifter - Google Patents

Abstract

PURPOSE:To obtain the super-precise X-Y shifter, which can be moved minutely in the X-Y-theta direction, by supporting one base by four elastic struts and driving the base by three rectilinear actuators. CONSTITUTION:The elastic struts 5 are set up at four corners of a Y roughly movable base 2 on an X roughly movable base 1, and support the minutely movable base 6. The base 6 is positioned within + or -5mum by the base 1 and 2, the accurate coordinates of the base 6 are detected by laser interference measuring instruments 17, 18, voltage bringing difference with a target value to zero by each closed loop control circuit 19, 20 is applied to piezoelectric elements 11- 13, and the base 6 is servo-controlled. The theta angular displacement of the base is detected by a laser measuring instrument 21, severally reverse phase voltage for X-axis compensation is applied to the piezoelectric elements 11, 12, and the base is compensated. Accordingly, a simple and light minutely movable mechanism is formed, and the roughly and minutely movable composite type super- precise X-Y shifter is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a reduction projection exposure apparatus or an electron beam lithography apparatus, and particularly to an ultra-precision XY movement apparatus suitable for use as a sample stage.

[Prior art]

The ultra-precision XY moving table used in the conventional above-mentioned equipment is required to have an ultra-precision positioning accuracy of 0.1 μm as well as a high-speed positioning function.
A compound movement mechanism that combines a coarse movement table and an ultra-precision xy6W movement table is often used.

In the above-mentioned conventional compound movement mechanism, for example, a Y coarse movement table moves in the Y axis direction on an X movement table that moves in the X axis direction, and an X fine movement table, etc.
The fine movement tables are stacked one on top of the other, resulting in a four-tier structure (2).This makes the structure complicated and expensive, and also increases the weight of the moving parts, which hinders high-speed positioning. Ta.

[Purpose of the invention]

The purpose of this invention was to solve the above problems, and to provide a simple and inexpensive Bue composite type ultra-precision XY.
The purpose of the present invention is to provide a mobile device.

[Summary of the invention]

This invention replaces the conventional XY two-stage fine movement mechanism.
A single table supported by four elastic columns is driven by three linear actuators to make fine movements in the X, Y, and θ directions.The XY coarse and fine movement has a simple structure and a lightweight fine movement mechanism. This is an ultra-precision XY movement device consisting of a complex movement mechanism.

[Embodiments of the invention]

Hereinafter, the configuration of an embodiment of the present invention will be explained with reference to FIGS. 1 to 3. In addition, in each figure, the same reference numerals are given to the same or equivalent parts. The XY coarse movement table is composed of an X coarse movement table 1, a Y coarse movement table 2, and motor drive mechanisms 3 and 4 for each of the above tables.
The XY two-dimensional positioning of the Y coarse movement table 2 is performed with a positioning accuracy of about ±5 μm over a movable range of about 50111111, but the above-mentioned technique is already known. A fine movement table 6 whose weight is supported by thin elastic columns 5 at its four corners is mounted on the Y coarse movement table 2, and the fine movement table 6 has an elastic deformation range of ±5 of the elastic column 5.
It can freely move slightly in the X, Y, and θ directions at about 0 μm.

A gap of approximately 100 μm is provided between the Y coarse movement table 2 and the BXX fine table 2, as shown in the second core, and the gap is not filled with high viscosity oil (for example, silicone oil) 7. The 70 layers of oil are for effective action,
Absorbs minute vibrations of the fine movement table 6.

L-shaped support frames 8°9.10 are fixed to the Y coarse movement table 2 at two locations in the X-axis direction and one in the Y-axis direction, and the L-shaped support frames 3, 9.10 and the fine motion table 6 are fixed to the Y coarse motion table 2.
A piezoelectric element actuator] I,
12.13 is inserted and fixed.

The piezoelectric element actuator 11, 12, 13 is one such as that shown in Japanese Patent Publication No. 49-26477, which utilizes minute displacement of the element length due to the electrostrictive effect of the piezoelectric element.
In this example, when a voltage of 600V DC is applied, approximately 20μ
A displacement of m is obtained.

The feature of this invention is that by using three piezoelectric actuators as described above, the fine movement table 6 can be moved in the X and Y directions.
The point is that it is possible to regulate not only the minute displacement in the direction but also the minute angular displacement in the θ direction. Therefore, the XY guide mechanism using the parallel spring mechanism of the fine movement table, etc., which was indispensable to the conventional device, is no longer necessary, and the structure can be made very compact.

As the fine movement table 6 moves slightly in the X and Y directions, the piezoelectric actuator will be slightly tilted in the XY plane, but as shown in FIG. 14, the constriction 14 is elastically deformable, and the elastically deformable support terminals 15, 1.6
are provided at both ends of the three piezoelectric element actuators. ], 7.18 is the fine movement table 6
19. 20 is a closed loop control circuit to be described later; 21 is a laser length measurement device for Yaw detection; 22 shows the Yaw closed loop control circuit.

Next, the effect will be explained. In the above structure, by changing the applied voltages to the piezoelectric element actuators 11, 12, and 13, the X, Y, and θ positional relationships of the fine movement table 6 with respect to the Y coarse movement table 2 can be changed, and the applied voltage The above positional relationship can be constrained as long as it does not change.

The method for controlling the XY excitation mechanism described above is as follows. That is, in FIG. 1, the X and Y positions of the fine movement table 6 with respect to the stationary coordinate system are each accurately detected by the laser interferometers 17 and 18 with an accuracy of approximately 0.02 μm. After the fine movement table 6 is positioned within ±5 μm of the target value given by the XY coarse movement table, the precise coordinates of the fine movement table 6 are detected by the laser interferometer 17 and 18, as shown in FIG. X shown in
, Y, a voltage is applied to the piezoelectric element actuators 11, 12, and 13 so as to make the difference from the target value zero, and servo control is performed. However, since these closed-loop position control techniques are well-known techniques, detailed explanations thereof will be omitted.

In the above control method, two piezoelectric element actuators 11 and 12 are provided in the X-axis direction, but normally the same control signal is given to both piezoelectric element actuators 11 and 12, thereby causing the fine movement table 6 to have a minute θ. It can be driven only in the X-axis direction without causing angular displacement (Yaw). However, when used in the XYY stage of a reduction projection exposure apparatus, even the slightest Yaw of the fine movement table 6 cannot be tolerated;
Within the movable range of mm, ±5 X IF' rad
The following Yaw is required. As a method of detecting and correcting Yaw of a fine movement table, there is a known example in which a table that rotates around a fulcrum is provided as shown in -km Japanese Patent Laid-Open No. 52-60074. As shown in Fig. 3, Ya of the fine movement table 6
W is detected using the laser length measuring device 21 for Yaw detection, and Y
If aw occurs, the fine movement table 6 is angularly displaced by applying voltages of opposite phases for X-axis direction correction to the two piezoelectric actuators 11 and 12 in the X-axis direction to correct the above-mentioned Yaw. It is something to do. In the above description, an example using a piezoelectric element actuator has been described, but the present invention is not limited thereto, and the same effect can be obtained by using a magnetostrictive element or an electromagnetic actuator that balances electromagnetic force and spring force.

〔Effect of the invention〕

As explained above, according to the present invention, the Yaw caused by the XY coarse movement table can be easily corrected by the fine movement table, so that the XY coarse movement table does not require high (guiding) accuracy, and therefore It has the advantage that it can be manufactured at low cost.

In addition, a laser length measuring device for Yaw detection is installed to constantly detect and correct Yaw, and the Yaw at each XY coordinate of the XY coarse movement table is
It also has the effect that the Yaw of the XY coarse movement table can be corrected by creating a map of the w value by measuring it in advance and angularly displacing the fine movement table based on this data.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view along the Y axis of FIG. 1, and FIG. 3 is a diagram showing a control method of the embodiment of FIG. 1. . Explanation of symbols 1...X coarse movement table, 2...Y coarse movement table, 5...
... Elastic strut, 6... Fine movement table, 7... Oil, 11°12.13... Piezoelectric element actuator, 1
7.18...Laser interferometric length measuring device, 19.20...Closed loop control circuit, 21...Laser length measuring device for YaW detection, 22...Yaw closed loop control circuit Patent attorney Junnosuke Nakamura

Claims (1)

[Claims] (ll) An XY moving table that can be moved in two dimensions, and an
In a coarse and fine movement joint type xy movement device provided with a fine movement mechanism. The XY@ movement mechanism includes a parallel guide mechanism provided between the fine movement table and the XY movement table, and at least three linear telescopic mechanisms provided between the XY movement table and the fine movement table. Ultra-precision X characterized by
Y moving device. (2) The ultra-precision XY moving device according to claim 1, wherein a piezoelectric actuator is used in the linear expansion and contraction mechanism. (3) One of the above linear telescopic mechanisms is arranged parallel to the X-axis, and the other linear telescopic mechanisms are spaced apart from each other by a finite distance in the X-axis direction and parallel to the Y-axis direction. Precision XY
Mobile device. (4) The parallel guide mechanism includes a parallel spring guide mechanism supported by at least three or more elastic columns, and further includes a viscous liquid interposed in the parallel gap between the XY moving table and the fine movement table. The ultra-precision x-y moving device according to claim 1, characterized in that: (5) X, Y to detect the X, Y position of the fine movement table
The ultrasonic device according to claim 3, further comprising respective position detectors, and configured to adjust the amount of expansion and contraction of the linear expansion and contraction mechanism according to the position error of the fine movement table with respect to the target value. Precision XY movement device. (6) A detector for detecting the Yaw of the fine movement table is provided, and two of the linear expansion and contraction mechanisms are arranged so as to expand and contract in parallel to each other according to the Yaw detected by the detector.
4. The ultra-precision XY moving device according to claim 3, characterized in that the amount of expansion and contraction of each of the linear expansion and contraction mechanisms is adjusted to be in opposite phases.