JPH01292288A - Vertical stage - Google Patents

Abstract

PURPOSE:To contrive to make a stage weightless and to realize a vertical stage suitable for high speed control, by mounting pressure control bellows to the stage. CONSTITUTION:Bellows 12 extending and contracting in a vertical direction by the pressure of a pressure control part 13 is provided to the under surface of a stage 11 and a measuring part 14 measures the moving distance of the stage 11 in the vertical direction to output the moving distance data to an operation part 15. The operation part 15 operates the pressure variation corresponding to the moving distance to input the value thereof to the pressure control part 13 which in turn controls the value of the pressure applied to the bellows 12 on the basis of said pressure variation. By this method, since the weight of the stage can be made weightless apparently, a vertical stage suitable for high speed control can be obtained.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a stage that controls movement in the vertical (vertical) direction, and more specifically, a bellows for pressure adjustment is attached to the stage.
Regarding the vertical stage, which has no appearance of superposition of stages, we aim to provide a vertical stage that can make the stage weightless and suitable for high-speed control. a bellows that expands and contracts in the vertical direction; a pressure adjusting section for supplying pressure to the bellows that can be adjusted at high speed in response to pressure fluctuations; a measuring section that measures the vertical movement distance of the stage; The apparatus includes a vertical stage characterized by comprising a calculation section that calculates a pressure fluctuation corresponding to a moving distance in a direction and controls the pressure adjustment section.

[Industrial application field]

The present invention relates to a stage whose movement is controlled in the vertical (vertical) direction, and more particularly to a vertical stage in which a pressure adjusting bellows is attached to the stage and the appearance of a stage heavy wall is completely eliminated.

[Conventional technology]

2. Description of the Related Art Vertical stages that control vertical movement have conventionally been used in various fields. Since there is no demand for high-speed control with conventional vertical stages, in order to support gravity, stage 1 is moved using rack and pinion 2, as shown in Figures 4(a) and 4(b). Alternatively, as shown in FIGS. 5(a) and 5(b), the stage 1 is driven by the motor 3 using a screw 4 that utilizes frictional force.

Incidentally, in recent years, synchrotron orbital synchrotron radiation (SO) has been used as an X-ray source to form fine patterns in semiconductor manufacturing.
R:5ynchrotron 0rbital Rad
Precision exposure apparatuses using the ion) have attracted attention and are being developed worldwide. This SOR precision exposure apparatus is an apparatus that exposes a wafer by using electromagnetic waves emitted when electrons having a speed close to the speed of light move in a circular orbit and are subject to acceleration. In such an apparatus, since the orbital radius of electrons is large, it is necessary to use a vertical stage for performing exposure. In addition to ion implantation equipment and semiconductor manufacturing equipment, vertical stages are also used in automatic drawing machines, machine tools, and the like. Precision stages used in semiconductor exposure equipment and the like need to be controlled as fast as possible because the speed of movement of the stage directly affects production volume (throughput). To achieve this, it is necessary to reduce the weight of the stage as much as possible, eliminate the fluctuating load when going back and forth between stages, and create a no-load state for the motor.

As a solution, for example, Fig. 6 (a), (b)
As shown in FIG. 1, a method has been proposed in which a balancer 5 having the same weight as the stage is attached to one of the vertical stages 1 using a wire 6 to reduce the weight or make the stage weightless.

In addition, as another method, a method has been proposed in which control is performed in the Z direction by changing the volume of fluid within the bellows.

[Problem to be solved by the invention]

However, in the conventional method using the balancer 5, it is very difficult to make minute adjustments to the balancer 5, and if the wire 6 to which the balancer 5 is attached is cut, it is very dangerous and has many problems.

In a method that utilizes changes in the fluid accumulation within the bellows, the load on the linear step motor in return is always a variable load, which complicates motor control and increases the size of the motor accordingly.

Further, since the fluid within the bellows is required to be an incompressible fluid, contamination is a constant problem in a semiconductor exposure apparatus, which poses many problems.

The speed of the stage in a semiconductor exposure apparatus affects throughput, so precise and high-speed operation is an important factor. To achieve this, it is necessary to reduce the weight to reduce friction or increase the motor performance. However, increasing the motor performance increases the size of the equipment itself, which is not a very desirable method, so the general trend is to reduce the weight of the stage. Most of the conventional exposure stages for semiconductors are horizontal stages that move in the X and Y directions on a plane. However, recently, as seen in SOR precision exposure equipment, there is an increasing need for a vertical stage that can move at high speed over long strokes in the X and Y directions. This control method requires adding force in the direction of gravity to the conventional control methods.

Therefore, an object of the present invention is to provide a vertical stage that can make the stage weightless and is suitable for high-speed control.

[Means to solve problems]

The above-mentioned problems include a bellows that is attached to the lower surface of the stage and expands and contracts in the vertical direction due to pressure, a pressure adjustment unit for supplying pressure to the bellows that can be adjusted at high speed in response to pressure fluctuations, and a pressure adjustment unit that can move the stage in the vertical direction. A vertical stage comprising: a measuring section that measures distance; and a calculating section that calculates pressure fluctuations corresponding to the distance moved in the vertical direction by the measuring section and controls the pressure adjusting section. resolved.

[Effect]

FIG. 1 is an explanatory diagram of the principle of the vertical stage of the present invention. In the figure, a bellows 12 that controls movement in the vertical direction is connected to the stage 11, and the bellows 12 is connected to the weight ffi (Ms) of the stage 11 and the bellows 12 from the outside.
The air pressure corresponding to the weight ffl (Mv) of the pressure adjusting part 13
Supplied via. In addition, the stage 11 has a measuring section 14.
The vertical movement distance (Z) of the bellows 12 from its natural length (L) is measured, and the output of this measurement section 14 is given to the calculation section 15. This calculation section 15 calculates a pressure fluctuation value (p) corresponding to the vertical movement distance, and controls the pressure adjustment section 13 based on the calculation result.

In the present invention, when the bellows 12 is at its natural length at the origin of the stage 11, when the moving distance (Z) of the stage 11 is actually measured by the measuring unit 14, the bellows 12 similarly expands and contracts by Z, and the spring of the bellows 12 If k is a constant, kZO force will act as a load on the motor etc.

If the calculation unit 15 calculates a force in the opposite direction to this force and controls the pressure adjustment unit 13 to change the air pressure, the stage 11 can be constantly made weightless, and the motor can be operated without load. It can be made to work. That is, M=PA, pressure fluctuation p=kZ/A=CX (constant of proportionality), where p is a function only of Z, and feedback is applied to the pressure adjustment section 13. It goes without saying that if C can be made very small, p can be made small and control becomes easier.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to an illustrated embodiment.

FIG. 2 is a front view showing the configuration of a vertical stage according to an embodiment of the present invention, and FIG. 3 is a side view of the vertical stage shown in FIG. 2.

Note that parts corresponding to those in FIG. 1 are denoted by the same reference numerals. In these figures, stage 11 (weight Ms) is Y(
The Y-direction stage llb moves in the horizontal) direction, and the Y-direction stage llb moves in the Z([
), and a Z-direction stage lla that moves in the ) direction. The Y direction stage llb is the Z direction stage ll
Movement is controlled in the Y direction by a rack and pinion 18 and a motor 19 via rollers 17 along the line guide 16 of a. The Z-direction stage lla is controlled to move in the Z-direction along the line guide 20 via a roller 21 by a screw 22 and a motor 23. A bellows (bellows cross-sectional area A, weight Mv) 12 that expands and contracts in the vertical direction is connected to the lower part of the Z-direction stage lla.
Air pressure (P=(Ms+Mv)/
A) is supplied via the pressure regulator 13. This air pressure is measured by a pressure gauge 24. Also, stage 11
A reflecting mirror 25 is fixed to the upper part of the mirror. Then, the laser beam emitted from the laser interferometer 26 is reflected by the reflecting mirror 27 and the reflecting mirror 25, and is returned to the laser interferometer 26 again, and the moving distance (Z) of the stage 11 in the Z direction is measured. That is, the laser interferometer 26 and the reflecting mirrors 25 and 27 constitute the measuring section 14, and the vertical movement distance (Z) of the bellows 12 from the natural length (L) is measured.

The output of this measurement section 14 is given to a calculation section 15 consisting of a central processing unit (CPU). This calculation section 15 calculates a pressure horn fluctuation value (p) corresponding to the vertical movement distance, and controls the plow pressure adjustment section 13 based on the calculation result.

Next, the operation will be explained. First, the stage (weight MsH1
On the bellows 12 (bellows area A1 weight Mv) on the lower surface,
A pressure (P) such that Ms+Mv=PA is injected through the pressure regulator 13. This places the stage 11 in a weightless state and the motor 23 into a no-load state. now,
The moving distance Z of the stage 11 from the origin point (at this time, the length of the bellows 11 is assumed to be the natural length) is measured using a laser interferometer 2.
6, the bellows 12 expands and contracts by Z, and a force F of kZ (spring constant k of the bellows 12) acts on the bellows as a load on the motor 23 in the opposite direction to the moving direction. This load acts regardless of the moving direction of the stage 11, and increases as the moving distance increases. Therefore, the pressure p (p=kZ/A=CZ,
C: proportionality constant) is calculated by the calculation unit 15, and the result is fed back to the pressure adjustment unit 13. By having these control JBa structures, it is possible to constantly create a no-load state on the motor 23 with respect to the movement of the stage 11, and to increase the speed of the stage 11 as a mass point system operation (a light mass moves with a small force). The control method becomes simple, the motor 23 can be made as small as possible, and the equipment can be made more compact. Also, in this example,
By making the stage 11 vertical, warping does not become a problem even if it is made thinner than a stage that moves in the horizontal direction, and it is possible to further reduce the weight.

In addition, in the above embodiment, the stage 11 may be provided with a bellows 12 attached to the lower side, which expands and contracts in the vertical direction under pressure to create a no-load state.
The lateral movement control and structure of 1 can be arbitrarily determined.

Further, although the stage 11 is measured by the laser interferometer 26, any device that can measure the moving distance in the vertical direction may be used.

〔Effect of the invention〕

As explained above, according to the present invention, the motor can operate in a no-load state, and high speed can be achieved with a small torque motor. In other words, it is possible to operate the motor at the same rotational speed without any loss.

Also, since the stage is unloaded, vibrations due to inertia can be reduced. Furthermore, since control can be performed only by pressure fluctuations, the control mechanism becomes simple.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the principle of the vertical stage of the present invention, Fig. 2 is a front view of the vertical stage of the embodiment of the present invention, Fig. 3 is a side view of the vertical stage of Fig. 2, and Fig. 4 ( a) and (b) are front and side views of a conventional vertical stage with a rack and pinion; Figure 5 (a) and Φ) are a front and side view of a conventional vertical stage with a screw; Figure 6 (a) and (b) are a front view and a side view of a vertical stage using a conventional balancer. In the figure, 11 is a stage, 12 is a bellows 12. 13 is a pressure adjustment section; 14 is a measurement section 14. 15 indicates an arithmetic unit. Patent Applicant Fujitsu Ltd. Representative Patent Attorney Akimoto Kuki Yoshiyuki Osuga UW STAY Shiba Miyazu≧Yoyou Tunro Fig. 2 $2 mm K”l sy->a (lisu1tIID Fig. 3 (α] Correctffi] f!] (b
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Claims (1)

[Claims] A bellows (12) attached to the lower surface of the stage (11) that expands and contracts in the vertical direction due to pressure; and a bellows (12) that can be adjusted at high speed against pressure fluctuations.
); and a measuring section (14) that measures the vertical movement distance of the stage (11).
), and a calculation unit (15) that calculates pressure fluctuations corresponding to the vertical movement distance by the measurement unit (14) and controls the pressure adjustment unit (13). Vertical stage.