JPS6342997Y2 - - Google Patents

Description

[Detailed description of the invention] <Technical field of the invention> The invention relates to a moving table device, so-called XY stage, which is applied to precision machine tools, robots, static measuring machines, semiconductor manufacturing equipment, etc., and performs ultra-precise positioning. .

<Background of the invention> Conventionally, an XY stage used for precision positioning is equipped with a flexible stage at the intersection of vertically and horizontally movable guides arranged orthogonally on a surface plate, and both movable guides are forced by a drive mechanism such as a linear motor. The flexible stage on the intersection is moved to the target position. However, such an XY stage is
Since everything from rough positioning to final fine positioning is performed by the operation of the linear motor that constitutes the drive mechanism, the mass of the moving parts is large, and
Since the linear motor and the movable guide are connected through a static pressure air joint, the static pressure air at the joint portion causes damping vibrations, which requires a long time for static and tight positioning. Therefore, in order to perform precise positioning quickly with the conventional XY stage, it is necessary to provide a special fine movement feed mechanism, which in this case complicates the mechanism and poses a problem in miniaturizing the stage.

<Purpose of the invention> The present invention focuses on the air gap on both sides in the transition direction in the static pressure air joint that connects the movable guide and the drive mechanism, and adjusts the size of the air gap to realize fine movement adjustment of the stage. The present invention provides a new XY stage that is smaller in size and speeds up precision positioning operations.

<Description of Embodiments> The drawing shows a pair of linear motors 2, 2, 2 that constitute a drive mechanism along vertical and horizontal parallel sides of a surface plate 1.
vertically and horizontally movable guides 3 and 3a are arranged on the surface plate 1, and an air bearing 4 is installed at the intersection of the guides 3 and 3a.
A flexible stage 4 is provided via 1, and the vertical,
Both ends of the horizontal movable guides 3, 3a are connected to linear motors 2, 2 via static pressure air joints 5, 5, 5, 5, respectively.
It is connected to a. As shown in FIG. 3, each of the static pressure air joints 5 includes joint walls 51, 51 that protrude to the front and rear sides of the movable guide 3 on the linear motor 2.
On the other hand, air blowing orifices 52, 52 are provided on the front and rear surfaces of the movable guide 3, and a pair of thrust type air bearings are formed between the two orifices 52, 52 and the joint walls 51, 51 with a diameter of 10 to 20 μm. It is provided with so-called air gaps 53, 53, which have a joint clearance of about 100 degrees. The present invention provides that the linear motors 2, 2a
constitutes a coarse movement mechanism for the flexible stage 4, and is connected to the static pressure air joint 5 with a control means 6 that controls the height of the supplied air and adjusts the sizes of the front and rear air gaps 53, 53, Free stage 4
This is a fine movement mechanism. The control means 6 controls each orifice 52, 52 and the pressure air source 5.
A pair of electric/pressure control valves 61, 61 interposed in the air passages 55, 55 between the control valves 4, 54, and a control valve drive section 62 connected to both control valves 61, 61 to control each of them. The position detector 63 detects the position of the flexible stage 4, and the difference from the command value 64 is calculated by a comparison circuit 65, and control is performed according to this deviation. The electric/pressure control valves 61 and 6 are operated by the valve drive unit 62.
1 to control the air pressure supplied to the pair of orifices, and relatively adjust the size of the front and rear air gaps 53, 53.

In the above embodiment, the supply air pressure to the front and rear orifices of the static pressure air joint was controlled, but in practice, the same effect can be obtained by keeping one pressure constant and controlling the other. In addition, the orifice can be configured on the linear motor side if necessary, and the drive mechanism is not limited to the linear motor, but can be selected within the technical scope of this proposal, such as a combination structure of a rotary motor and a feed screw. Of course you can.

When a command to move the flexible stage 4 is issued, the vertical and horizontal movable guides 3 and 3a are moved at high speed by the linear motors 2 and 2a, and the flexible stage 4 at the intersection of the movable guides is moved at high speed toward the vicinity of the target position. . When the flexible stage 4 reaches the vicinity of the command target position, the linear motors 2 and 2a stop, and rough positioning is completed. Next, fine movement adjustment is performed by adjusting the air gap of the static pressure air joint 5. In such fine adjustment, the stage position is detected by the position detector 63, and the difference from the command value 64 is detected by the comparison circuit 65.
The air pressure supplied to both the orifices 52, 52 of the static pressure air joint 5 is controlled to be large or small according to the deviation, and the front and rear air gaps 53, 53 are relatively changed in size to control the movable guide. The flexible stage 4 is moved slightly.

In the embodiment shown in FIG. 3, the supply pressure on the right side of the joint is set to P+ΔP, the supply pressure on the left side is set to P-ΔP, and both air gaps 53, 53 are adjusted accordingly to H+.
By changing ΔH and H−ΔH, the movable guides 3 and 3a, that is, the flexible stage 4, moves slightly by ΔH.

<Effects of the invention> As described above, the present invention connects the ends of the vertically and horizontally movable guide, which is equipped with a flexible stage at the intersection, to a drive mechanism as a coarse movement mechanism via a static pressure air joint, and By linking the supply air pressure control means to the joint and adjusting the size of the front and rear air gaps to finely move the flexible stage, the drive mechanism performs high-speed coarse positioning followed by fine positioning using the air gap, allowing for ultra-precise positioning. Positioning can be done quickly. In addition, in the present invention, especially during fine positioning, the drive mechanism is stopped and only the movable guide is moved slightly, so the weight of the movable part is reduced and the response speed is increased. Furthermore, since fine positioning using air gap control only changes the film thickness of the air, there is no damping vibration at all compared to conventional linear motor-based static pressure air joints, and high-speed positioning is possible. Moreover, because of the non-contact drive using the static pressure air joint, components other than those in the thrust direction are not transmitted, improving movement accuracy. Furthermore, the fine movement of the flexible stage is achieved by adjusting the air gap in the hydrostatic air joint, and there is no need to incorporate a separate special fine movement mechanism, so there is no risk of increasing the size of the device. Since adjustments are made to the flexible stage, it is sufficient to share one position detector to detect the position of the flexible stage during each adjustment, which contributes to the miniaturization and simplification of the device, resulting in a simpler configuration. It has the effect of achieving the purpose of the invention.

[Brief explanation of the drawing]

Figure 1 is a plan view of the XY stage, Figure 2 is the
FIG. 3 is an enlarged view of a static pressure air joint portion showing an embodiment of the present invention. 2, 2a... Drive mechanism, 3, 3a... Movable guide, 5... Static pressure air joint, 53... Air gap, 6... Control means.

Claims (1)

[Scope of Claim for Utility Model Registration] An XY stage in which a flexible stage is provided at the intersection of vertically and horizontally movable guides, a drive mechanism for coarsely moving the flexible stage connected to both ends of each of the vertically and horizontally movable guides; A static pressure air joint having air gaps at the front and rear in the transition direction, interposed between both ends of each movable guide and a drive mechanism, and a control means for finely moving the flexible stage by adjusting the size of the front and rear air gaps in the static pressure air joint. An XY stage consisting of.