JPS6020513A - Moving table device having attitude control function - Google Patents

Abstract

PURPOSE:To obtain the accuracy of rectilinear movement with high accuracy without being affected by the accuracy of finishing and linear accuracy of a guide by controlling only a minutely displaced member mounted to a moving table device and controlling an attitude. CONSTITUTION:Minutely displaced members 4b, 4b' fitted to pads such as rear pads 3b, 3b' are extended so that an interval between a pad 3 and a guide 2 is kept to (d) at the position of the starting of movement, the members 4b, 4b' are shrunk with an approach to the central section of movement, and minutely displaced members 4a, 4a' fitted to front pads 3a, 3a' are extended after the members pass through the central section of movement, thus controlling an attitude so that an error theta on the accuracy of pitchings is brough to zero. Members such as minutely displaced members 6a', 6b are extended so that the interval between the pad and the guide is kept to (d') at the position of the starting of movement, said members 6a', 6b are shrunk with an approach to the central section of movement, and minutely displaced members 6a, 6b' are extended after the members pass through the central section of movement, thus controlling the attitude so that an error theta' on the accuracy of yawings is brought to zero.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to devices in many fields that require linear precision of high sheath limbs, such as transfer mechanisms of length measuring machines, feeding mechanisms of precision processing machines,
The present invention relates to a moving table device applied to a scanning mechanism for an original plate and a photosensitive plate in a semiconductor exposure apparatus.

Conventional table straightness accuracy (pitching, yawing)
was determined by the processing accuracy of the guide, so the linearity of the guide must be strictly controlled for accuracy. Even if the guide is processed and manufactured with high precision, the guide may deteriorate due to aging due to long-term use. There is a problem that the linear accuracy of the line is degraded. Furthermore, if the table posture is controlled by controlling the gas pressure supplied to the gas supply pad that forms part of the movable table device, especially if the gas pressure is controlled low, There is also the problem that rigidity deteriorates.

The present invention has been proposed in view of the above-mentioned problems, and its purpose is to provide a small displacement member in a movable table device and control the member to solve problems in processing accuracy and linear accuracy of the guide. It is possible to obtain high straight-line accuracy even when the movement occurs, and the performance (rigidity) as a moving table device
An object of the present invention is to provide a movable table device 15- having an attitude control function that does not cause any change in the movement of the table.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIGS. 1(a), (b), and (C) are views showing one embodiment of the present invention, where (a) is a front view and (b) is a front view.
(C) is a side sectional view of a portion taken along line A, -A' and line B = B', and (C) is a plan view of (a). 1 is X in the diagram
With a slide (moving table) that moves in the direction, four gas supply pads 3a+3a are connected to the fixed guide 2.
', 6b, and 6bt, it is floating in the Z direction in the figure. 4a, 4a', 4b, 4b' are four minute displacement members, which are the slide 1 and the pads 3a, 3a'.
, 31) and 3b', and a piezoelectric element or a diaphragm member that expands and contracts with fluid pressure is used as the part. 5a, 5a', 5b.

5b' are four gas supply pads, slide 1 is shown in Figure (7).
) Constrain in the Y direction. 6a, 6a', 6b,
6b' is the side of the four minute displacement parts, which are interposed between the slide 1 and the .xi.rads 5a, 5, a', 5b, and 5b', respectively.

Figure 2 (a), (1)) and Figure 6 (a), (
b) is a diagram exaggerating the behavior of the moving table during pitching and yawing, respectively;
) shows the case where the control of the present invention is not carried out, and (1)) shows the case where it is carried out.

First, a method for controlling the attitude of the moving table during pitching will be explained with reference to FIG. The method is to measure the position of the table in the straight direction and the straight line accuracy of the table,
If there is an accuracy error, the position of the table in the straight direction and the amount to be corrected are stored in a memory (not shown). In actual control, the position of the table in the straight direction is detected by a position detector (not shown), and the amount to be corrected at that position is detected by the minute displacement members 4a, 4 while the table is moving.
b.

By controlling 4a' and 4b', the accuracy error measured in advance is corrected. Note that if the straightness accuracy is constantly measured using a laser interferometer (not shown) or the like, the above-mentioned preliminary measurement is not necessary, and the minute displacement members 4a, 4b are measured based on the signals from the laser interferometer or the like.

4a'14b' may be controlled.

In Fig. 2(a), the weight of moving parts such as slides and gas supply pad 3 a + 3 b + 3'' + 6
Unless the supply pressure to b' changes, the distance d between the pad and the guide 2 remains constant, so the slide 1 moves in a convex manner along the convex guide 2. For that reason θ
A pitching accuracy error of this angle occurs.

In FIG. 2(b), in which the control of the present invention is performed, first, at the movement start position, the minute displacement members 4Lz46' attached to the rear and rear rads 3b, 3b, and 46' are used to maintain the distance between the pad and the guide at d. The members 4b, 41)' are contracted as they approach the center of movement, and after passing the center of movement, the minute displacement members 4a, 4a' attached to the front panels 6a, 3a' are extended. As a result, attitude control is performed so that the pitching accuracy error θ is reduced to zero.

It is obvious that when the guide 2 has a concave shape, the method of controlling the minute displacement member (contraction and expansion) performed in the case of a convex shape can be reversed. Therefore, when the guide 2 has an uneven shape, it goes without saying that the above-described control methods for the case of a convex shape and a concave shape may be combined.

Next, we will explain how to control the posture of the moving table during yawing.
This will be explained according to FIG. The figure shows a case where the guide 2 is curved to the right with respect to the straight traveling direction. Figure 3 (a
), gas supply pads 5a, 5b, 5a', 5b
As long as the supply pressure to
Since the distance d' between the slide 1 and the guide 2 is kept constant, the slide 1 moves along the shape of the guide 2. This results in a yawing accuracy error of angle θ'. In FIG. 6(b), in which the control of the present invention is performed, first, at the movement start position, for example, the minute displacement members 6a' and 6b are extended so as to maintain the distance d' between the pad and the guide, and as they approach the center of movement, By contracting the members 68' and 6b and extending the minute displacement members 6a and 6b' after passing the center of movement,
Attitude control is performed so that the yawing accuracy error θ' becomes zero.

Furthermore, if the guide 2 is curved to the left with respect to the straight traveling direction, it is obvious that the minute displacement member should be controlled in the opposite way to the above case; Of course, it is possible to use a combination of control methods.

Note that the errors Δ and Δ′ shown in FIG. 2(b) and FIG. 6(b), respectively, are exaggerated as described above, so in reality, they are It is a value that can be ignored.

As explained above, the present invention performs posture control by controlling only the minute displacement member provided in the movable table device, so high linear accuracy is achieved without being affected by the processing accuracy or linear accuracy of the guide. Furthermore, there is a significant effect on the performance of the movable table device.

[Brief explanation of drawings]

FIGS. 1(a), (1)), and (C) are diagrams showing one embodiment of the present invention, in which (a) fcl, front view, and (1)
)) is a side sectional view of a portion taken along lines A, -A, ' and B-B' in (a), and (C) is a plan view of il-i (a). Figure 2 shows I), (1)) and Figure 6 (a).
, (b! is a diagram exaggerating the behavior of the moving table during pitching and yawing, respectively, and (a) is a diagram showing the behavior of the moving table during pitching and yawing, respectively.
b) shows the case where it is carried out. 1...Slide, 2...Guide, 3a
+ 3a' 16b+ 3 b'+ 52+ + 5
t+' + 5b + 51)'...Gas supply pad, 4a +4a' + 41)l 4b' +6
8'162' +6b +6b'...Minor displacement member. Patent applicant Canon Co., Ltd.

Claims (1)

[Scope of Claims] 1. In a sliding movable table device that is movable with respect to a guide via a fluid supply pad, the fluid supply pad itself or a micrometer disposed between the fluid supply pad and the slide. A moving table device having an attitude control function, characterized in that the attitude of the table is controlled by controlling a displacement member while the table is moving. 2. A movable table device having an attitude control function according to claim 1, characterized in that a piezoelectric element or a diaphragm member is used as the minute displacement member.