JPH0659589B2 - Stage feeding device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage feed device, and particularly to a liquid cylinder device suitable for precision positioning with a relatively long stroke, such as for fine pattern processing or inspection in a semiconductor manufacturing apparatus such as LSI. The present invention relates to a coarse / fine movement stage feed device using the.

[Prior Art] In various semiconductor manufacturing apparatuses that process or inspect a fine pattern such as an LSI including an exposure apparatus using light, an electron beam, an X-ray, or the like, a wafer to be processed or a mask for exposure is used. Alternatively, hold the reticle on the stage and position it precisely by linear feed. Since such a stage feed device requires a relatively long stroke, coarse movement feed with low positioning accuracy that performs high-speed feed to the vicinity of the target stop position, and target stop of the stage that is roughly positioned near the target stop position In general, a feed mechanism that performs both the function of finely positioning the position and the fine movement feed is provided. Conventionally, a biaxial feed screw system in which the feed screw mechanisms are double stacked for each function, or Two feed screw parts with lead difference are provided on one feed shaft 1
The shaft differential feed screw type was the mainstream.

However, in the conventional device that performs coarse and fine movement feed only with these feed screw mechanisms, there is no center of gravity of the stage on the central axis of the feed screw, in other words, there is no center of gravity of the stage on the line of action of force, so it is a vertical type. When it is installed and used, an overhang load is applied to the guide bearing that guides and supports the stage, and twisting occurs between the guide rail and the guide bearing, which impairs bearing life and guide accuracy. If it needs to be placed in the atmosphere, there are problems such as seizure of the feed screw and guide bearing due to evaporation of lubricating oil, and the feed drive motor must be configured to withstand vacuum. A feed screw mechanism and a motor with a complicated structure that are difficult to vacuum seal with a bellows etc. are placed outside the vacuum chamber, and the guide rail is set inside the chamber. Even if the movement of the feed screw is transmitted to the stage supported and guided by the transmission mechanism, both feed screw mechanisms for coarse and fine movement must be placed outside the chamber, so the required stroke of the stage An installation space longer than the full length is required outside the chamber.

Therefore, the inventors of the present invention can easily adopt a configuration in which the center of gravity of the stage is located on the line of action of force, and can store and arrange the coarse motion feed stroke portion in the stage, and cause seizure in a vacuum atmosphere. Especially, when the feed screw mechanism is arranged outside the vacuum chamber, the one shown in FIG. 4 is used as a stage feed device for precision positioning which has a simple structure and can make the protruding portion outside the chamber more compact than the conventional one. Proposed to.

In FIG. 4, the stage 1 is guided and supported by linear guide shafts 2a and 2b so as to be linearly moved in the y-axis direction. A piston cylinder assembly 3 is arranged in the stage 1, and the cylinder side of the assembly 3 is in a fixed relationship with the stage 1. The assembly 3 constitutes the coarse feed means of the stage 1, and moves the stage 1 relative to the piston rod 5 by the fluid 11 supplied and discharged via the flexible tubes 6a and 6b. A clamp device 4 is attached to the stage 1 so as to surround the piston rod 5, so that the stage 3 can be locked after the coarse positioning feed rough stop by the assembly 3, that is, the stage 1 can be locked to the piston rod 5. There is. A bifurcated fine feed rod 12 is connected to the tip of the piston rod 5, and the bifurcated tip of the rod 12 is a fine feed nut 8.
It is fixed to the housing block 13 having. The nut 8 is screwed into a fine movement feed screw 7 supported by a bearing 10 so that the rotation of the screw 7 by the drive motor 9 finely moves the piston rod 5 via the housing block 13 and the forked rod 12. Has been done.

In the apparatus shown in FIG. 4 having the above-described configuration, in coarse movement feed of the stage 1, first, the motor 9 is servo-locked and the feed screw 7 and the feed nut 8 with a rotation stop mechanism are locked so as not to move relative to each other. One method is to do it after that. In this case, the piston rod 5 remains stationary at the fixed position, and the pressurized fluid (5 to 7 kgf / cm ² ) is supplied and discharged through the flexible tubes 6a and 6b to the cylinder side of the piston cylinder assembly 3, that is, Stage 1
The forward and backward movements are performed to perform coarse movement feed for the required stroke. When the stage 1 reaches a position within the predetermined coarse position accuracy near the target stop position, the clamp device 4 is actuated to stop the movement of the stage 1, whereby the coarse positioning of the stage 1 is performed.

Then, the fine movement is performed. In this case, the clamp device 4
Is left active. The feed screw 7 is rotated by a required number of rotations by the rotation of the drive motor 9. At this time, since the feed nut 8 is fixed to the housing block 13, the housing block 13 is screwed by the screw 7 every time the feed screw 7 makes one rotation. Of the lead, the movement is transmitted to the piston rod 5 via the rod 12, and the stage 1 is finely moved via the clamp device 4.

In the example of FIG. 1, the piston rod 5, the forked rod 12, the feed unit including the housing block 13 and the feed nut 8, and the feed screw 7 are all arranged coaxially, and the center of gravity of the stage 1 is coaxially arranged. The central axes of the respective coaxial elements including the guide shafts 2a and 2b are arranged in the same plane. That is,
Since the line of action of force penetrates through the center of gravity of the stage 1, it is possible to minimize the occurrence of twisting of the guide shaft and its bearing due to overhang load when this is arranged vertically. .

When the apparatus of the above-mentioned embodiment is arranged in a vacuum chamber, for example, a lubricating oil having a low vapor pressure is used for the guide shafts 2a and 2b, and the sliding surface of the piston rod of the piston cylinder assembly 3 has a vacuum seal structure. By placing the mechanism on the feed screw side in the atmosphere outside the chamber and arranging it from the piston rod 5 in the mechanism chamber on the stage 1 side, it is possible to make it suitable for a low vacuum chamber. In this case, most of the coarse feed stroke is accommodated in the vacuum chamber, so the apparatus outside the chamber becomes very compact.

In addition to this, the guide shafts 2a, 2b, the clamp device 4, the piston rod 5, and the tubes 6a, 6b are vacuum-sealed in the vacuum chamber by bellows, O-rings, etc., to highly prevent the evaporation of the lubricating oil. Therefore, the addition of these vacuum sealing elements makes the system suitable for high vacuum chambers.

In this example, an example in which the fine feed side is locked and operated during coarse feed is described. For example, in this case, the fine feed screw 7 is interlocked to move the feed nut 8 during coarse feed. Direction, and the clamp device 4 is operated in a state where the relative movement between the stage 1 and the piston rod 5 is reduced to improve the positioning accuracy of the coarse feed and to operate the clamp device 4 to move the piston rod 5. You may measure damage prevention.

As described above, in the stage feeding device shown in FIG. 4, the coarse movement feeding means is constituted by the piston cylinder assembly. Therefore, even if this is arranged in the stage at the center line position passing through the center of gravity of the stage Is not a problem, and the piston rod, the clamping means and the guide rail are simple rod-shaped and can be vacuum-sealed by the bellows even when they are arranged in the vacuum chamber. It is possible to dispose the coarse movement feeding means for carrying out the above in the chamber, and only the feed screw device for the fine movement feeding needs to be arranged outside the chamber, so that the arrangement of the device outside the chamber becomes compact accordingly. Furthermore, since the actuator for coarse feed is a piston cylinder assembly, the structure is simpler than that of the feed screw method, and the positioning to the final stop target position can be performed by the feed screw device of the fine feed means, so the positioning accuracy is high. You can hope for.

By the way, in the stage feed device of FIG. 4, a normal piston-cylinder assembly 3 is used as the coarse-moving feed means, and its structure is such that the piston 3a connected to the piston rod 5 is as shown in FIG. The nipples 14a and 14b for supplying and discharging the working fluid are slidably in contact with the inside of the cylinder tube 3b through a seal ring 3c, and the two cylinder chambers 3d and 3e partitioned by the piston have tubes nipples 14a and 14b.
The structure was located near both ends of 3b.

Therefore, in the stage feed device of FIG. 4, it is necessary to make the working fluid supply / discharge tubes 6a and 6b for coarse movement feed have a flexible structure outside the stage and to pipe the tubes inside the stage 1. Flexible tube along with the movement of 6
Since a and 6b bend together, the spring constants of 6a and 6b are constantly changing, which causes uneven feeding during fine feed.
Since the internal piping of the stage is required, the stage body must be subjected to complicated processing, and the presence of a movable tube changes its spring constant even when the tube internal pressure changes and its airtightness when placed in a vacuum chamber. It has been pointed out that it is disadvantageous in that it is difficult to avoid complication of the structure around the feeding device.

[Object of the Invention] An object of the present invention is to eliminate these drawbacks while making use of the above-mentioned features of the coarse / fine movement stage feed device in which the above-mentioned fluid cylinder device and feed screw device are combined. It is an object of the present invention to provide a stage feeding device which does not require flexible tube piping for supplying and discharging a working fluid to and from which the feeding accuracy and reliability are high.

[Configuration of the Invention] In order to achieve this object, according to the present invention, in a stage feed device that linearly moves a stage guided and supported by a linear guide, a piston / cylinder assembly in which a working fluid supply / discharge passage is disposed in a piston rod is provided. And a clamp mechanism that locks relative movement between a piston and a cylinder of the piston-cylinder assembly, the coarse-motion feed means having a cylinder side of the assembly fixed to the stage for coarse-motion feed of the stage, and the clamp. And a fine movement feed means having a screw feed mechanism for finely feeding the stage through the piston cylinder assembly in a state of being locked by the mechanism.

In one preferred aspect of the present invention, the cylinder is a closed cylinder having no opening other than a piston rod insertion port, and two working fluid supply / discharge ports respectively communicating with two cylinder chambers partitioned by a piston in the cylinder. The passages are both independently located in the piston rod,
It is adapted to be connected to a working fluid supply source outside the cylinder via the inside of the piston rod.

Further, in a specific embodiment of the present invention, the piston rod is formed by a hollow rod having a working fluid supply / discharge passage formed therein, and a hollow pipe for independently forming another supply / discharge passage is provided in the hollow rod. By being fixedly arranged, two independent supply / discharge passages for both cylinder chambers are formed in the piston rod.

When the stage moves, it can be driven by feeding pressurized fluid into a supply / discharge passage communicating with one cylinder chamber, or by sucking and discharging the working fluid from one cylinder chamber via the supply / discharge passage. However, either is acceptable.

[Advantages of the Invention] In the stage feeding device of the present invention, the above-described advantages are obtained by combining the coarse movement feeding means having the piston cylinder assembly operable by the pressurized fluid and the fine movement feeding means using the screw feeding mechanism. In addition to being obtained, the working fluid is supplied to and discharged from the cylinder chambers on both sides of the piston in the cylinder fixed to the stage through the supply and discharge passages in the piston rod. Therefore, it is possible to eliminate the causes of the above-mentioned drawbacks.

A preferred embodiment of the present invention will be described below with reference to the drawings.

[Embodiment] FIG. 1 shows an embodiment of the stage feeding apparatus of the present invention.
The same parts as those in the example of FIG. 4 are designated by the same reference numerals. That is, in FIG. 1, the stage 1 is guided by the linear guide shafts 2a and 2b so as to be linearly moved in the y-axis direction. The piston cylinder assembly 30 arranged on the stage 1 has a structure as shown in FIG. 2, for example, and the cylinder side is in a fixed relationship with the stage 1. In FIG. 2, the assembly 30 includes a piston 30a, a cylinder 30b, and a cylinder 30 fixed to the piston.
Piston rod 50 extending to the outside through the insertion hole 30f of
The cylinder 30b does not have an opening communicating with the outside, other than the insertion opening 30f. The piston rod 50 is a hollow rod whose inside is the head side cylinder chamber 30e.
To form a working fluid supply / discharge passage 50b. Also, a small diameter hollow pipe 51 is fixedly arranged inside the hollow piston rod 50, and the hollow portion inside the pipe is the rod side cylinder chamber.
A hydraulic oil supply / discharge passage 50a for 30d is formed. Both passages 50a and 50b in the piston rod 50 are connected to the joint 15 at the tip of the rod.
Are independently communicated with the nipples 16a and 16b provided in the above, and are connected to a working fluid supply source (not shown) from here.

The assembly 30 constitutes the coarse feed means of the stage 1,
The stage 1 with respect to the piston rod 50 by the fluid 11 supplied and discharged through the passages 50a and 50b in the piston rod 50.
Move relative to. The piston rod is again on stage 1.
A clamp device 4 is attached so as to surround 50, and it is possible to lock (clamp) the stage 1 to the piston rod 5 after the coarse positioning feed rough stop by the assembly 30 is stopped. A bifurcated fine feed rod 12 is connected to the tip of the piston rod 5 via a joint 15. The bifurcated tip of the rod 12 has a fine feed nut 8 in a housing block.
It is fixed at 13. The nut 8 is screwed into a fine feed screw 7 supported by a bearing 10, and the rotation of the screw 7 by the drive motor 9 finely moves the piston rod 50 through the housing 13, the bifurcated rod 12, and the joint 15. It is like this.

In the apparatus of the embodiment shown in FIG. 1 having the above-described configuration, in coarse movement feed of the stage 1, first, the motor 9 is servo-locked to relatively move the feed screw 7 and the feed stopper pupil 8 with a rotation stop mechanism. One way is to lock it so that it doesn't exist. In this case, the piston rod 5 remains in the fixed position, and pressurized fluid (5 to 7 kgf / cm ² ) is supplied and discharged from the nipples 16a and 16b of the joint 15 through the passages 50a and 50b in the piston rod 50. The piston side of the piston cylinder assembly 30, that is, the stage 1
The forward and backward movements are performed to perform coarse movement feed for the required stroke. When the stage reaches a position within the predetermined coarse position accuracy near the target stop position, the clamp device 4 is actuated to stop the movement of the stage 1, whereby the coarse positioning of the stage 1 is performed.

Next, the fine movement feed is performed by the feed screw device, but since this is the same as in the example of FIG. 4, description thereof will be omitted.

In this embodiment, the hollow pipe 51 in the piston rod 50
Is preferably fixed in the rod 50, which prevents vibration of the pipe 51 in the rod 50. As a preferred embodiment for this purpose, FIG. 3 shows a hollow pipe 151 having an outer diameter which fits exactly inside a hollow rod 150 as a piston rod, and is continuous on the outer surface of the pipe 151 in the longitudinal direction. After chamfering, the pipe 15
One is shown inserted into rod 150. In this structure, the hollow portion of the hollow pipe 151 forms one supply / discharge passage 50a, the chamfered portion forms the other supply / discharge passage 50b, and since the pipe 151 is closely fitted in the rod 150, Vibration of the internal supply / exhaust pipe does not occur.

In the present invention, the example in which the assembly 30 is driven by the pressurized fluid to move the stage 1 has been described. For example, when air is used as the fluid and the load of the stage is small and the feed speed is not so fast, It may be driven by so-called vacuum exhaust, in which one of the supply / discharge passages is opened to the atmosphere and the other supply / discharge passage is depressurized to atmospheric pressure or less, for example, within a maximum of 1 kgf / cm ² , and so on. It is effective in reducing fluid leakage in the rod packing 30g shown in FIG. 2 when used in the chamber.

[Effects of the Invention] As described above, according to the present invention, the advantage of using the fluid cylinder device as the coarse movement feed device in the case of performing the coarse / fine movement stage feed in combination with the feed screw device can be fully exerted. However, since the working fluid supply / discharge passage is provided in the piston rod, the problem of pipe tube bending that accompanies the movement of the stage can be eliminated, and the tube is not required. Therefore, it is possible to eliminate the need for processing for the stage body for piping, there is no obstruction to the sealing by the bellows, etc., and the stage itself can be made compact and the space factor around the stage can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a partially cutaway embodiment of the present invention, FIG. 2 is a longitudinal sectional view of a piston cylinder assembly as a main part, and FIG. 3 is a sectional view showing an internal structure of a piston rod according to another embodiment. 4 and 5 are perspective views showing a conventional example and FIG.
The drawing is a vertical sectional view showing a conventional piston cylinder assembly. 1: Stage, 2a, 2b: Linear guide shaft, 30: Piston cylinder assembly, 30a: Piston, 30b: Cylinder, 50: Piston rod, 50a, 50b: Supply / discharge passage, 5
1: Hollow pipe, 16a, 16b: Nipple.

Claims (5)

[Claims] 1. A stage feed device for linearly moving a stage guided and supported by a linear guide, wherein a working fluid supply / discharge passage has a piston cylinder assembly disposed in a piston rod, and the cylinder side of the assembly is attached to the stage. A fixed coarse movement feed means for coarsely feeding the stage, a clamp mechanism for locking relative movement between the piston and the cylinder of the piston cylinder assembly, and a piston cylinder cylinder locked by the clamp mechanism. A fine feed unit having a screw feed mechanism for finely feeding the stage through the assembly. 2. A cylinder is a closed cylinder having no opening other than a piston rod insertion port, and two working fluid supply / discharge passages, which communicate with two cylinder chambers partitioned by a piston in the cylinder, are both in the piston rod. The stage feed device according to claim 1, wherein the stage feed device is independently arranged. 3. A piston rod comprises a hollow rod having a working fluid supply / discharge passage formed therein, and a hollow pipe for independently forming another supply / discharge passage is fixedly positioned in the hollow rod. The stage feeding device according to claim 2, which is characterized. 4. The stage feeding device according to claim 2, wherein the stage is moved linearly by feeding a pressurized fluid to a working fluid supply / discharge passage communicating with one of the cylinder chambers. 5. The stage according to claim 2, wherein the working fluid is sucked and discharged from the one cylinder chamber through a working fluid supply / discharge passage communicating with the one cylinder chamber to linearly move the stage. Stage feed device.