JPH03211816A - Air supplying and recovery equipment for stage - Google Patents

Abstract

PURPOSE:To prevent the damage of an air pad and a static pressure bearing, by a method wherein, when main gas supply is interrupted by service interruption and the like, and at the same time, pump means for gas recovery are interrupted, a gas recovery inlet of the static pressure bearing is opened to the atmospheric air. CONSTITUTION:When main gas supply is interrupted, a switching means 314 connects a static pressure bearing inlet to a backup supplying means 320 side by the output of a main gas supply interrupting means 316, so that gas is continuously supplied to the static pressure bearing by the backup supplying means 320, and the static pressure bearing continues normal operation. In the case of service interruption, the interruption of main gas supply and that of gas recovery are detected, and backup gas supply is performed. Further, by detecting the interruption of gas collection, an opening means 331 is operated, and a static pressure bearing collecting inlet is opened to the atmospheric air. Thereby pumps 333, 335 for air recovery are interrupted, so that the air withdrawal caused by service interruption and the like is prevented, and the damage of an air pad 303 and a transfer guide can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stage air supply/recovery device for supplying and recovering gas to a static pressure bearing for guiding the movement of a stage moving in a reduced pressure container.

[Prior Art] Semiconductor integrated circuits have become increasingly highly integrated in recent years, and exposure devices (aligners) used to manufacture them are also required to have higher transfer precision. For example, 2
In 56 megabit DRAM class integrated circuits, the line width is 0.
．． An exposure device that can print patterns of about 25 microns is required.

As an exposure apparatus for printing such ultrafine patterns, an apparatus that performs so-called proximity exposure using orbital synchrotron radiation (SOR-X-rays) has been proposed.

In such an X-ray exposure apparatus, a mask and a wafer are exposed to X-rays in a reduced pressure atmosphere. Therefore, in order to align the mask and the square with an accuracy commensurate with the above-mentioned transfer accuracy, the stage that holds the wafer and moves along the movement guide and its movement guide are also placed in a reduced pressure atmosphere. Furthermore, in order to avoid the occurrence of bumps as much as possible, an aerostatic pressure bearing without a sliding part is used as a bearing part between the movement guide and the stage. Metal or sintered metal air pads and ceramic air pads are available as air pads for gas-static bearings, but ceramic air pads have uniform micropores and are more uniform than metal pads. It has the advantage that a high flow rate and pressure can be obtained.

However, on the other hand, ceramic air pads are brittle.
It has the disadvantage that if air escapes due to a power outage or the like and hits the moving guide, damage such as chips or cracks is likely to occur. Of course, air pads and movement guide sides made of metal or sintered metal also suffer from the problem of damage due to power outages, etc., although there are varying degrees of severity.

[Problems to be Solved by the Invention] This invention was made in view of the problems in the conventional example described above, and provides a stage that prevents air leakage due to power outages, etc., and thereby prevents damage to air pads and movement guides. The purpose is to provide air supply and recovery equipment.

[Means for Solving the Problems] In order to achieve the above object, the stage air supply and
The recovery device includes: a main gas supply means for supplying gas to a gas supply port of a hydrostatic bearing for guiding movement of a stage moving in a reduced pressure container; a pump means for reducing pressure in a gas recovery port of the hydrostatic bearing; Main gas supply stop detection means for detecting main gas supply stop, gas recovery stop detection means for detecting operation stop of the pump means, backup gas supply means,
It is characterized by comprising a switching means for switching the gas supply source from the main gas supply means to the backup gas supply means when the main gas supply is stopped, and an opening means for opening the gas recovery port to the atmosphere when the gas recovery is stopped. are doing.

The main gas supply means supplies, for example, air, and the backup gas supply means supplies, for example, nitrogen gas.

As the main gas supply stop detection means, a pressure detection means for detecting the pressure of air supplied to the hydrostatic bearing inlet can be used, and as the switching means, a A valve may be used to switch between the main gas supply means and the backup gas supply means. Alternatively, as having the functions of both the main gas supply stop detection means and the switching means,
A valve that operates on a differential pressure between the main supply air and the backup nitrogen gas may also be used.

Furthermore, the movement guide is often a linear air bearing.

[Function] According to the above configuration, during normal operation, the switching means connects the hydrostatic bearing inlet to the main gas supply means, and the opening means closes to connect the hydrostatic bearing recovery port to the pump means. . In this connected state, it operates in the same way as the conventional one.

When the main gas supply is stopped, the switching means connects the hydrostatic bearing inlet to the backup supply means side based on the output of the main gas supply stop means. Therefore, gas is continuously supplied to the hydrostatic bearing by the backup supply means, and the hydrostatic bearing continues to operate normally. This avoids contact between the stage (particularly the air pad) and the hydrostatic bearing, thereby preventing damage to the stage, air pad, and hydrostatic bearing.

During a power outage, main gas supply stop and gas recovery stop are detected. When this main gas supply stop is detected, the above-mentioned backup gas supply is performed. In addition, the opening means is activated by detecting the stoppage of gas recovery.
The hydrostatic bearing recovery port is opened to the atmosphere. This stops the air recovery pump and prevents the air pressure in the decompression chamber from increasing due to the supply of backup gas.

In addition, as the switching means, an electric valve with a backup gas supply means connected to the normal side is used. Under normal conditions, this electric valve is energized and switched to the main gas supply means side. During a power outage, this electric valve is switched to the main gas supply means side. It may also be possible to switch to the backup gas supply means side by cutting off the energizing power and returning to the normal side.

[Effect] As described above, according to the present invention, when the main gas supply is cut off, gas is immediately continuously supplied from the backup supply means, so air leakage from the hydrostatic bearing is prevented, It is possible to prevent contact between the stage (especially the air pad) and the hydrostatic bearing and damage to the stage, air pad, and hydrostatic bearing.

In addition, in the event that the main gas supply is cut off and the gas recovery pump stops simultaneously due to a power outage, etc., the gas recovery port of the hydrostatic bearing is opened to the atmosphere.
This prevents the backup gas from causing an extreme increase in air pressure within the decompression chamber, and prevents damage to the beryllium window for introducing X-rays provided in the decompression chamber.

[Example] FIG. 1 shows the configuration of an X-ray aligner according to an example of the present invention. In the same figure, 11 is an SOR device;
It is placed on a device stand 12, and X-rays 1 are emitted from a light emitting point 13.
Emit 4. 21 is a first mirror whose reflective surface is processed to have a convex shape in order to magnify the sheet beam-shaped 5OR-X rays 14 elongated in the X (horizontal) direction in the Y (vertical) direction; This is a second mirror that reflects the X-ray flux 15 so that its central axis is horizontal.

The X-ray flux reflected by the second mirror 22 is the illumination light 1 for exposure.
6 into the aligner body 40.

23 is a mirror chamber for creating a desired vacuum atmosphere around the first mirror 21 and the second mirror 22; 24 is a first mirror drive device used to adjust the attitude of the first mirror 21; 25 is a second mirror chamber; A second mirror drive device 26 is used to adjust the attitude of the mirror 22, and is a mirror mount.

30 is a shutter unit, which includes a shutter stay 31 and shutter shafts 32 and 3 attached to the shutter stay 31.
3 and each shirt axis 32° 32 questions and 33.33
It is composed of shutters 34 and 35 stretched between them. The shutter films 34 and 35 each consist of an endless steel belt having a rectangular opening (not shown) on each side longer than the dimension of the exposure area.

41 is a mask on which a transfer pattern is formed from an X-ray opaque material such as gold, 42 is a movable mask stage on which the mask 41 is mounted, and 43 is a mask stage 4 for carrying the mask 41.
2, a mask chuck 44 for fixing on the mask 4;
1 is a wafer to which an image is to be transferred; 45 is a movable wafer stage on which the wafer 44 is mounted; 46 is a wafer 44;
A wafer chuck 47 is used to fix the wafer on the Eva stage 45, and 47 is the mask stage 42 and the wafer stage 4.
5, etc., 48 is an aligner base on which the main frame 47 is placed, and 49 is an air spring for supporting the aligner base 48 on the floor 1. The aligner base 48 has at least three air springs 49
It is supported at three locations.

50 is a helium chamber for creating a desired helium atmosphere around the shutter unit 30, the mask 41 on the mask stage 42, and the wafer 44 on the wafer stage 45. Further, 5152 is a piping spool for connecting the mirror chamber 23 and the helium chamber 50, that is, the aligner main body 40 while maintaining the respective seven atmospheres.
53 is a bellows for flexibly connecting the mirror chamber 23 and the aligner body 40; 54 is a bellows for connecting the illumination light 16;
This is a beryllium window that insulates the vacuum atmosphere in the mirror chamber 23 from the helium atmosphere in the helium chamber 50.

FIG. 2 shows the stage unit parts of the stage apparatus in FIG.
The details of the part consisting of etc. are shown below.

The stage unit shown in FIG. 2 is entirely assembled using the main frame 47 of the aligner body 40 as a base.

The entire aligner body 40 including the stage device is disposed within the main chamber 201.

In the same figure, 202 is a Y coarse movement stage, which has a pair of Y coarse movement guide bars 20 attached to the main frame 47.
3, it is guided by static pressure and can move up and down. This Y coarse movement stage 202 is connected to a balancer cylinder 205 attached to the main chamber 201 via a pair of balance belts 204 for the purpose of offsetting its own weight. It is driven and positioned by an electric cylinder 206.

Furthermore, a coarse movement stage 208 is statically guided by a pair of X coarse movement guide bars 207 attached to the Y coarse movement stage 202, and is movable left and right. This X coarse movement stage 208 is driven and positioned by an X drive electric cylinder 209 attached to the Y coarse movement stage 202. A wafer fine movement stage 210 for finely positioning the wafer 44 and a laser length measurement mirror 211 are mounted on the X coarse movement stage 208 .

A mask θ stage 213 is attached to the AA frame 212 attached to the main frame 47 at a2 length. The main frame 47 is connected to the main chamber 201 via a frame connector 214, and the entire stage fits within the main chamber 20i.

FIG. 3 shows the configuration of a stage air supply/recovery device for the stage device of FIG. 2. In the figure, 301 is a stage, which corresponds to the Y coarse movement stage 202 and the X coarse movement stage 208 in FIG. 302 is a linear guide that guides the stage 301, and is a Y coarse movement guide bar 203 in FIG.
and corresponds to the X coarse movement guide bar 207. A ceramic pad (trade name: CERAPAD) 303 is attached to the surface of the stage 301 facing the linear guide 302.
A linear air bearing (LAB) is formed between the linear guide 302 and the stage 301 by blowing air from the ceramic pad 303 toward the linear guide 302. 310 is an air supply device that supplies air to the ceramic pad 303. Also,
The stage 301, linear guide 302, etc. described above are placed in a reduced pressure atmosphere. In order to maintain this reduced pressure atmosphere, that is, to prevent the air ejected from the ceramic pad 303 from leaking into the reduced pressure atmosphere, grooves 304 and 305 and the air that has flowed into these grooves 304 and 305 are placed around the ceramic pad 303. An air recovery device 330 is provided for recovery.

Next, the operation of this stage air supply/recovery device will be explained.

In FIG. 3, when power is supplied, air is supplied from a main air source (pump) 311 to a clean air unit 312, where it is purified and then passed through a manual valve 313, an electric valve 314 and a regulator 315. It is supplied to the ceramic bat 303. As a result, clean air is blown out from a large number of fine holes on the surface of the ceramic pad 303 on the linear guide 302 side, and the stage 301
LAB is formed between the linear guide 302 and it becomes possible to move along the linear guide 302 with low friction.

The air blown out from the ceramic pad 303
4, most of which is recovered by rotary pump 333 via electric valves 331 and 332. In addition, those that are not collected in the groove 304 and reach the groove 305 are transferred to the rotary pump 33 via an electric valve 334.
Recovered by 5. Ceramic bat 30 like this
By collecting the air blown out from 3 through two recovery systems, the blown air is prevented from leaking into the reduced pressure atmosphere. 336 and 337 are Pirani gauges.

During a power outage, when the main air source 311 stops supplying air and the air pressure supplied from the clean air unit 312 drops below a predetermined value, the pressure switch 316 detects this and switches the electric valve 314 to the auxiliary air source 320 side. . As a result, the regulator 322 and the electric valve 314 are transferred from the auxiliary air source nitrogen cylinder 321 to the regulator 3.
Nitrogen gas is supplied to the ceramic pad 303 via the stage 301, and an air pad is maintained between the stage 301 and the linear guide 302. That is, by backing up with this nitrogen gas, the 5th stage 301 and the linear guide 30
The stage 301 is aligned with the linear guide 30 so that the interval of 2 is maintained.
2, and the ceramic pad 303 is prevented from being damaged due to a power outage. In addition, in order to confirm that either main air or backup nitrogen gas is finally supplied to the stage 301 at a predetermined pressure, a pressure switch 317 detects the pressure.
When the pressure falls below a predetermined value, similar prevention is achieved by emergency stopping the operation of the stage.

During this power outage, the rotary pumps 333 and 335 and the exhaust pump (not shown) for the main chamber 201
has also stopped. Therefore, the pressure inside the main chamber 201 increases due to the nitrogen gas supplied from the auxiliary air source 320, which may have a considerable adverse effect on the main chamber 201 and the like. Electric valve 33 during power outage
2. 334 is an electric valve 331 that is tilted to the closed side shown in the figure.
switches to the atmosphere side. As a result, the air recovery system 330
is opened to the atmosphere, and the pressure inside the main chamber 201 can be prevented from becoming extremely higher than atmospheric pressure. Electric valves 332 and 334 are connected to Pirani gauges 336 and 3, respectively.
It is also effective when the rotary pumps 333 and 335 stop for some reason and the pressure for recovery etc. increases. 323 is a pressure sensor for detecting the amount of nitrogen gas in the nitrogen cylinder 321.

In addition, in the above, an example was explained in which a pressure switch and an electric valve that is switched by the output of this switch are used as the switching valve. It is also possible to use a valve that operates based on the differential pressure between the supply air and the backup nitrogen. Alternatively, an auxiliary air source may be connected to the normal side of the electric valve, and in the event of a power outage, the air source may be switched to the backup side by energizing the electric valve.

[Brief explanation of drawings]

FIG. 1 is a side configuration diagram of an X-ray aligner according to an embodiment of the present invention, FIG. 2 is a perspective view showing the stage device part of the aligner in FIG. 1 in more detail, and FIG. FIG. 3 is a block diagram showing the configuration of an air supply/recovery device of the stage device shown in FIG. 2; 301: Stage 302: Linear guide two pads 310: Air supply system 311: Main air source 314.331, 332.334: Electric valve 31.6
, 317: Pressure switch 320: Auxiliary air source 330/air recovery system

Claims (5)

[Claims] (1) A device for supplying and recovering gas to a static pressure bearing for guiding movement of a stage moving in a reduced pressure container, the main gas supply means supplying gas to a gas supply port of the static pressure bearing; a pump means for decompressing the gas recovery port of the hydrostatic bearing; a main gas supply stop detection means for detecting a stop in the supply of the main gas; a gas recovery stop detection means for detecting a stop in the operation of the pump means; a gas supply means; a switching means for switching the gas supply source from the main gas supply means to the backup gas supply means when the main gas supply is stopped; and an opening means for opening the gas recovery port to the atmosphere when the gas recovery is stopped. A stage air supply/recovery device characterized by comprising: (2) The main gas supply stop detection means is a pressure detection means for detecting the pressure of air supplied to the hydrostatic bearing inlet,
2. The stage air supply system according to claim 1, wherein the switching means is a valve that switches between the main gas supply means and the backup gas supply means based on a signal from the pressure detection means.
Collection device. (3) The stage air supply/recovery device according to claim 2, wherein the main gas supply means supplies air, and the backup gas supply means supplies nitrogen gas. (4) The main gas supply stop detection means and switching means,
4. The stage air supply/recovery device according to claim 3, wherein the valve is operated by a pressure difference between main supply air and backup nitrogen gas. (5) The stage device according to claim 1, wherein the movement guide is a linear air bearing.