JPH0697051B2 - Fluid flow mechanism for hydrodynamic bearings - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention applies a fluid to a moving object such as an air slide, which is used in various processing machines used in a vacuum atmosphere, a measuring apparatus, an exposure printing apparatus used in a semiconductor lithography process, and the like. The present invention relates to a mechanism for supplying or discharging fluid from a moving object.

[Prior art]

The material of the fluid supply or fluid discharge piping tube for the fluid bearing that can be used in a vacuum atmosphere is limited due to gas generation and the like.

As a piping tube for a moving body in the atmosphere, particularly an air slide, there is, for example, a flexible nylon tube or the like, and a structure that allows the tube to follow the moving body by deforming the flow path as the moving body moves. I was taking it. However, in a high vacuum, nylon releases gas and deteriorates the degree of vacuum, making it difficult to use. Further, a tube made of metal or the like that does not generate a gas even when used in a vacuum atmosphere, for example, a stainless tube cannot be bent and therefore cannot be used as a piping tube for an air slide or the like.

〔Purpose〕

The present invention eliminates the above-mentioned drawbacks of the conventional example, maintains a vacuum atmosphere, can be used for moving objects such as air slides, and the movement performance of the moving object is a movement resistance force of the tube, for example, restoring force of a deformed nylon tube. An object of the present invention is to provide a fluid circulation mechanism for a fluid bearing that does not have an adverse effect due to the above.

[Explanation of Examples]

A description will be given below with reference to FIGS. FIG. 1 is a schematic view of a vertical stage supported by an air bearing used in a vacuum atmosphere according to an embodiment of the present invention. In the figure
The MF is a main frame, which has a cover (not shown) on the front surface and the rear surface and is fixedly arranged on the ground to make the internal space a vacuum or a specific gas filled state. Subframe SF is the mainframe
The MF is suspended from above by MF1R and MF1L, and is lightly contacted with rubber materials FGR and FGL, etc. from below by MF2R and MF2L to prevent vibration and lateral shift. Y2M is an electric motor composed of a cylinder, a motor, etc. fixed to the subframe SF, and its rod Y2G is coupled to the upper surface Y2SU of the vertical movement stage Y2S.

The stage Y2S is composed of an upper plate Y2SU, a lower plate Y2SL, a front plate Y2SF, etc., guided by a pair of axes Y2R, Y2L, and a subframe SF.
The inside is moved up and down by the drive of the electric motor Y2M. A pair of Y
2AU and Y2AL are air bearings for the shaft Y2R, and Y2K is a cylinder connecting them. The same applies to the axis Y2L. Stage Y2S is axis
Guided by Y2R, Y2L and this air bearing.

The periphery of the air bearing of this device is isolated from the external vacuum atmosphere by a labyrinth seal or the like. Y2BR, Y2BL is a constant tension spring mechanism fixed to the main frame MF, Y2SR, Y2SL is a steel belt that connects the constant tension spring mechanism Y2BR, Y2BL and the stage Y2S, and is constantly wound by the spring mechanism Y2BR, Y2BL to Y2S. By replacing the weight to balance such weight, the overload of the electric motor Y2M when the stage Y2S moves up and down is reduced. Y2LR and Y2LL are support bars for locking the stage Y2S, which is symmetrically arranged with respect to the drive axis Y2G. Y2PR and Y2PL include the piezoelectric element etc., and the stage Y2S
This is an electromechanical locking mechanism for pressing and locking the bars Y2LR and Y2LL after stopping. This makes the stage Y2S
The vertical position of is maintained. Bar constriction Y2FR, Y2F
L has a function of elastically absorbing the displacement of the stage Y2S with respect to the axes Y2R and Y2L at the time of locking, and constitutes an elastic locking mechanism with a piezoelectric element or the like.

The stage Y1S is further installed in the stage Y2S. The lower plate Y2SL of the stage Y2S has an electric motor for moving the stage Y1S.
Y1M is fixed and moves in the vertical (Y) direction on the axes Y1R and Y1L (not shown) by the vertical movement of the rod Y1G. Y1AR is Y2AU
A similar air bearing. Like the stage Y2S, the constant tension spring mechanisms Y1BR and Y1BL are used to lift and lower the stage Y1S instead of the weights that balance the load on the Y1S by constantly winding the steel belts Y1SR and Y1SL fixed to the sledge Y1S. The electric motor Y1M is being miniaturized.

Y1PC, Y1PR, and Y1PL lock the stage Y1S with respect to the stage Y2S by a locking mechanism using a piezoelectric element as before. Therefore, even if Y2S is moved in this state, Y1S moves together with Y2S. The stage Y1S further includes a movable stage XS that moves in the horizontal (X) direction.
The moving electric motor XM of the stage XS is fixed to the side portion Y1M of S. The stage XS moves on the axes XL and XR by the lateral movement of the rod XG of the electric motor XM. FLX is a mechanism that elastically connects rod XG and stage XS to stage X with respect to fixed axes XL and XR.
Absorb the deviation of S. The same applies to FLY1 and FLY2. XAU is axis X
The same air bearing as for L. Axis XR is similarly equipped. In addition, a locking mechanism (not shown) including the same voltage element and constricted bar as described above is also provided at a position facing the axis XG. The stage XS is further equipped with a stage ΘZS that is rotatable and movable in the direction of the rotation axis, and also has a function of adsorbing a wafer WF for circuit pattern exposure.

An annular rotary stage ΘS is attached to the inner surface of the front plate Y2SF of the stage Y2S at a position facing the wafer WF, and a mask MK provided with a circuit pattern is attracted to the rotary stage ΘS.

The front plate Y2SF is formed with an opening EXO through which an exposure light beam EX such as an X-ray, an electron beam or an ion beam can enter.
An opening WMIO for loading and unloading K and / or the wafer WF is formed.

Openings SWO and MWO are formed in the sub-frame SF and main frame MF at positions facing the opening WMIO when the stage Y2S reaches the lower end position. MPS is a pre-alignment stage of the wafer WF, and the aligned wafer WF is adsorbed to the stage ΘZS by a vacuum buffer chamber, a hand (neither is shown) or the like. The mask is also adsorbed on the stage ΘS by the same method.

Next, the stage Y2S is raised to a predetermined exposure position,
If necessary, fine alignment of the mask and the wafer is performed before that, and the parallel light flux EX for exposure is sequentially exposed at the exposure position.

At this time, since the stage Y2S moves up and down the exposure range at a low speed, the mask and the wafer move in unison, and as a result, scanning exposure is performed with the parallel light flux EX. When the exposure is completed, the stage Y2S descends to the lower end, and the wafer and / or the mask are replaced. Thus, the stage Y2S is preferable because it has both a mask and / or wafer transfer function and a constant-speed feed function during exposure, for example.

Also, when the stage Y2S moves, the stage Y1S lock function Y1
It is locked in the Y direction by the PC, and the stage XS is also locked in the X direction by the electromechanical locking mechanism XP such as a piezoelectric element.
Further, the stage .THETA.ZS and / or the stage .THETA.S are also locked in their respective moving directions by a servo lock mechanism (not shown).
This is preferable because each stage can be surely moved independently without interfering with each other.

When Y1SL and Y1SR are locked by Y1PL and Y1PR during Y2S movement, the tension fluctuation of the constant tension springs Y1BL and Y1BR acts only on Y2S and does not reach Y1S.
It is preferable because the positional relationship of 2S can be maintained.

FIG. 2 is a rear view of a vertical stage supported by a hydrostatic bearing used in a vacuum atmosphere according to an embodiment of the present invention.

8a to j are piping arms made of stainless steel, and four piping holes are provided inside the block made of Al or the like.
a and 9b are relay blocks, four piping holes are provided inside the block at positions facing the piping holes of the piping arms 8a to j, and the rotary joints 10a to 10o are connected to the piping arms. It is a 4-system joint that has a rotating function so that it can be rotated in the center. Rotary Join 10
a to j and relay blocks 9a and 9b are installed in the subframe SF, stage XS, stage Y1S, and stage Y2S, respectively.
The rotary joints 10k-o are floating in the air. Piping to each table is connected by a combination of piping arms 8a to j, relay blocks 9a and 9b, and rotary joints 10a to 10o. The rotary joints 10a, 10f, 10j on the sub-frame SF are connected to an air supply source (not shown) outside the vacuum atmosphere through a fixing hole (not shown) provided in the sub-frame.

The stage Y2S and the subframe SF are connected by piping arms 8a, 8b and rotary joints 10a, 10b, 10k, and air can be supplied from the outside to a fixed pipe (not shown) in the stage Y2S. Even if is moved, each rotary joint can be rotated and the pipe arms 8a and 8b can move in the directions (arrow A) to open each other.
Between 10b, it can be expanded and contracted smoothly. Therefore, there is no resistance such as restoring force when the stage is moved by the tube.

Piping arms 8c, 8d, 8 from subframe SF to stage XS
e, 8f, rotary joint 10c, 10l, 10d, 10e, 10m, 10
f, connected by a relay block 9a fixed to the stage Y2S via a fixing portion 9a1 with the same structure as the piping arm, and air can be supplied from the outside to a fixing hole (not shown) in the stage XS. When the stage Y1S moves, the joints 10c and 10f can be smoothly expanded and contracted. Also, by fixing the relay block 9a to the stage Y2S, the pipe between the relay block 9a and the joint 10c does not move when the stage Y2S moves, and the movement of this pipe causes the stage Y2S and the stage XS to move. There is no adverse effect on the posture accuracy during the period.

Piping arms 8g, 8h, 8i,
8j, rotary joint 10g, 10n, 10h, 10i, 10j, 10o, 10
n, 10o, fixed structure 9a to stage Y2S with the same structure as piping arm
It is connected by a relay block 9b fixed via the so that the joints 10g and 10j can be smoothly expanded and contracted when the stage Y1S moves. Also, by fixing the relay block 9b to the stage Y2S as in the case of stage XS,
Relay block b and Jyoint 10g when moving on stage Y2S
The pipe between and is fixed so that the stage Y2
It is designed so as not to adversely affect the posture accuracy between the S and the stage Y1S.

With the above piping, stage XS, stage Y1S, stage Y2S
The gas supplied to each stage is supplied to an air bearing for guiding movement of each stage through a fixing hole (not shown) provided in a member forming each stage. Further, the gas ejected from the air bearing passes through another fixing hole (not shown) and is discharged through the above pipe.

FIG. 3 is a detailed view of the rotary joint 10k, in which (a) is a vertical sectional view and (b) is a horizontal sectional view. The configuration of other rotary joints is similar to this. Reference numeral 11 denotes a housing, which has four connection ports 12a to 12d, an inner pipe 13, 14, 15 is inserted into a hollow tubular member consisting of a hollow shaft 19 and four systems are concentrically formed with a lid 16. Gas passages are formed, and four systems of gas passages are formed by the housing 18 having the four connection ports 17a to 17d and the lids 19, 20, and 21. Both four-system gas flow paths are used, one for supplying gas to the air bearing and the other three for discharging gas from the air bearing. Housing 11, inner pipe 13,14,1
5, a first member 101 having four systems of expected flow paths, that is, a hollow shaft 22, that is, a pneumatic circuit, and a second member 102 having four systems of pneumatic circuits, which includes the housing 18 and the lids 19, 20, and 21. Means that the ball bearings 23a and 23b can relatively rotate.
Moreover, the supply of the pneumatic circuits of the four systems of each other and the discharge paths of the four systems are connected so as to communicate with each other, so that air cannot leak to the outside from the rotatable connection portion, and the mutual flow paths do not flow. It is sealed by Teflon seals 24a, 24b, 24c. In order to prevent the communication holes 30a to 30d provided at one location on the outer peripheral portion of the hollow shaft 22 and the connection ports 17a to 17d from being blocked by rotation, a groove 31a to the outer periphery of the hollow shaft 22 in the circumferential direction.
c and the air reservoir 32 are provided so that the communication hole and the connection hole are in a flow relationship through the groove or the air reservoir during rotation.
The cross-sectional areas of the concentric pneumatic circuits of the four systems are made equal to the cross-sectional areas of the four connection ports provided in the housings 11 and 18, and the supply / exhaust efficiency due to losses such as fluid resistance. So that it does not fall. The Teflon seals 24a, 24b, 24c are attached by a push-up ring 25 fixed by screws 26 so as not to shift in the axial direction,
Air leaking from the screw 26 is sealed by a lid 27 with an O-ring. The piping arms 8a to 8j are fixed by bolts so as to fit the connection ports 12a to 12d and 17a to 17d. In the joints 10a, 10b, 10c, 10f, 10g, and 10j, either the first member 101 or the second member 102 is fixedly set on the frame or stage, and is connected to the internal fixed pipe instead of the pipe arm. ing. 1st by the above-mentioned structure
Since the member 101 and the second member 102 can rotate via the ball bearings 23a and 23b, the piping arm can rotate about this joint, and air leakage does not occur even if this rotary motion is performed. .

Instead of the piping arm of this embodiment, four pipes, that is, a connecting pipe may be provided for each of the four pneumatic circuits. The material of the piping arm may be aluminum ceramic or the like for weight reduction.

[Explanation of effects]

As described above, according to the present invention, it is possible to supply a fluid to a moving object such as an air slide and to discharge a fluid from the object while maintaining a vacuum atmosphere, and there is an effect that the moving object piping resistance is not adversely affected. .

[Brief description of drawings]

FIG. 1 is a schematic view of a vertical stage apparatus using an embodiment of the present invention, FIG. 2 is a rear view of the same, and FIG. 3 is a detailed view of a rotary joint. In the figure, MF …… Main frame SF …… Subframe XS …… Horizontal movement stage Y1S …… Vertical movement stage Y2S …… Vertical movement stage Y2AU, Y2AL, Y1AR …… Air bearings 8a to j… … Piping arm 9 …… Relay block 10a ～ o …… Rotary joint 11 …… Housing 13 …… Inner pipe 14 …… Inner pipe 15 …… Inner pipe 18 …… Housing 22 …… Hollow shaft 23a, b …… Ball Bearings 24a to c ... Teflon seal

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Makoto Higomura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takuo Kariya 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Satoku Yamamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (56) References: Showa 50-73016 (JP, U) Showa 52-15674 (JP, U) Actually opened 54-47114 (JP, U)

Claims (4)

[Claims] 1. A mechanism for supplying and discharging fluid to and from a fluid bearing, comprising a piping arm having a supply path for supplying fluid to the fluid bearing and a discharge path for discharging fluid, and a plurality of piping arms. A fluid distribution mechanism for a fluid bearing, comprising: a rotary joint that rotatably connects the pipe arms to each other, and the rotary joint communicates the supply passages and the discharge passages of the pipe arms. 2. The fluid circulation mechanism according to claim 1, wherein the piping arm is made of stainless steel. 3. The fluid flow mechanism according to claim 1, wherein the plurality of piping arms and the rotary joint are installed in a high vacuum. 4. The fluid flow mechanism according to claim 1, wherein the fluid bearing is an air slide.