JPH04127417A - Moving stage for drawing apparatus use - Google Patents

Abstract

PURPOSE:To obtain a moving stage, for drawing apparatus use, whose constitution is simple, which can be moved at high speed and which is not vibrated at its stop operation by a method wherein a proportional, integral and derivative PID control operation is executed at the second half of a stage movement period and, when the stage approaches a target position, the RID control operation is changed over to a P control operation and a pulse-clearing operation. CONSTITUTION:A PID control operation is executed from the time t3 when the speed of a moving stage is increased, a smooth control operation is finished and a stage wants to approach a target position. A control voltage V which has been corrected by a control amount DELTAXc is fed to a motor driving part 23 from a control operation part 22; a vibration is set to a state that it is extremely small and that the moving stage 21 is close to its stop operation. When the stage approaches its target position, a control operation to the motor driving part 23 from the control operation part 22 is changed over to a P (proportional) control operation. When the stage is set within a prescribed stop position error (at the time t5), a pulse-clearing, operation is instructed to the motor driving part, and it is avoided that the stage is moved inessentially by the influence of an excess stored pulse. Thereby, it is possible to realize the moving stage, for drawing apparatus use, which can be positioned with good accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a moving stage for a drawing device, and more particularly to a moving stage for a drawing device in which a method for driving the moving stage is improved.

(Prior art) A lithography device such as an electron beam lithography device or a focused ion beam device stores lithography pattern data in a storage device in advance, and draws a predetermined pattern with a beam onto a material placed on a moving stage. It is supposed to be done.

FIG. 4 is a diagram showing an example of the configuration of an electron beam drawing apparatus. The electron beam Bi emitted from the electron gun 1 is controlled on and off by a blanking electrode 2, focused by subsequent electron lenses 3 and 4, and deflected in a two-dimensional direction by a deflection electrode 5, after which it is applied to a material (for example, a wafer). 6. Here, the material 6 is placed on a moving stage 7 that is movable in two dimensions. 8 is an exchange chamber in which the material 6 is exchanged, and 9 is a vacuum chamber containing these components therein.

Batter data for performing electron beam drawing on the material 6 is stored in the external storage device 10.

The CPU circuit 11 controls the transfer of pattern data stored in the external ratio t6 device 10 and calculates the amount of stage movement. Then, the blanking control circuit 12. Beam deflection control circuit 13 and stage movement control circuit 14
Each control signal is sent to the The blanking control circuit 12 controls the voltage applied to the blanking electrode 2, the beam deflection control circuit 13 controls the voltage applied to the deflection electrode 5, and the stage movement control circuit 14 controls the movement of the moving stage 7. Control. As a result, a predetermined pattern on the material 6 is drawn.

(Issues to be Solved by the Invention) In the case of such an electron beam lithography apparatus, the movement time of the moving stage 7 has a large influence on the lithography throughput. Therefore, the movable stage 7 is required to move in a short period of time, and the vibration generated when stopped is also required to be small.

The present invention has been made in view of these points, and its purpose is to realize a moving stage for a drawing device that has a simple configuration, can move at high speed, and does not have vibrations during stopping.

(Means for Solving the Problems) The moving stage for a drawing apparatus based on the invention of Claim], when driving the moving stage on which the material to be drawn is placed, after the stage moving period! 1'-, PID control is performed, and when approaching the position 1], PID control is switched to P control and pulse clear.

The moving stage for a drawing device according to the invention of claim 2 performs feedforward control in the first half of the stage moving period, and smoothly controls the moving stage in the second half of the stage moving period when driving the moving stage on which the drawing target material is placed. control and PID control, [When approaching the target position, PID
It is characterized in that it is configured to switch from control to P control.

(Function) In the invention of claim 1, PID control is performed in the latter half of the stage movement period, and when the target position is approached, the PID control is switched to P control and pulse clear.

In the second aspect of the invention, feedforward control is performed during the first half of the stage movement period, smooth control and PID control are performed during the second half of the stage movement period, and when the target position is approached, the PID control is switched to P control.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the present invention. In the figure, 20 is a driving servo motor, and 21 is a moving stage driven by the servo motor 20. Although not shown, a material for electron beam drawing is placed on the moving stage 21. 22 is a moving stage 21
This is a control calculation unit that generates a control voltage for controlling the movement of the moving stage 21 in response to position information. As the control calculation unit 22, for example, a microcomputer is used.

Reference numeral 23 denotes a motor drive unit including a V/F converter that receives the control voltage V from the control calculation unit and converts it into pulses of a corresponding frequency F. The output pulse of the motor drive section 23 is given to the servo motor 20 as a drive pulse. 2
A pulse encoder 4 is attached to the rotating shaft of the servo motor 2 and outputs a signal corresponding to the number of rotations of the motor, and its output is input to the control calculation section 22. 25 is a laser p1 length system for detecting the position of the moving stage 21, and 26 is a position converter that receives the output of the laser p1 length system 25 and converts it into a signal indicating the position of the moving stage 21. The output of the position converter 26 is input to the control calculation unit 22 as position information.

The operation of the device configured as described above will be explained as follows.

In this embodiment, first, feedforward control is used to move the moving stage 21 at high speed, then smooth control is performed to slowly decelerate the stage, and when it approaches a stop, PID (proportional, integral, differential) control is performed. Further, when the stage is about to stop, PID control is switched to P control to prevent vibration of the movable stage 21 when the stage is stopped. Below, regarding these four control technologies, the stage speed waveform in Figure 2,
The description will be made with reference to the diagram shown in FIG. 3 showing changes in the stage control amount.

(1) Feedforward control Feedforward control is to predict the movement mode of the moving stage 21 in advance to perform optimal movement. When the speed diagram waveform enters the drive human power of the control calculation unit 22, the control calculation unit 22 generates a control voltage V according to the drive input.
is generated and given to the motor drive unit 23. FIG. 2 is a speed diagram of the drive signal manually input to the control calculation unit 22 at this time. Time 1 from the start of stage movement. Until then, more pulses are applied than normal driving pulses to make the rise of the speed waveform steeper. Therefore, the amount of change in speed with respect to time becomes large, and the movable stage 21 can quickly rise to a desired speed.

(2) Smooth control During the period from time t1 to time 12 in Figure 2, the stage moves at a constant speed, but when it enters the stop mode at time t2, until time t3, the stage moves at a constant speed as shown in the figure. The drive curve is exponentially smoothed. For this reason, when the stage approaches the [1 mark position], the speed is gradually slowed down, thereby preventing vibrations from occurring when the stage stops due to rapid deceleration. Note that this smooth control and the feedback control described above are not feedback control based on stage position information, but oven loop control based on a predetermined speed waveform.

(3) PID control This control is performed from time t3 when the speed of the moving stage 21 decreases, smooth control ends, and the stage approaches a certain target position. The method is such that the control calculation section 22 calculates the control amount while always knowing the position information of the moving stage 21 from the pulse encoder 24 or the laser length measurement system 25, and feeds it back to the drive section of the servo motor 20. In other words, this control is proportional (P
motion).

This is a combination of integration (l operation) and differentiation (D operation) and is called PID control.

This PID control is used, for example, in oil refinery plants, and has been established as a technology for stabilizing the plant. Therefore, by using PID control, vibrations when the stage is stopped can be suppressed. In the calculation formula, the current position of the moving stage 21 is Xl, and the target position is X. When expressed as a difference equation, the difference value ΔX is expressed by the following equation.

ΔX, -X. -X, ... (1) (1
) control amount ΔX output from the control calculation unit 22 using the formula
c is expressed by the following formula.

ΔX, − to ΔX, + to ΣΔX.

10, (ΔX, −ΔX, −+) ... (2) where K: proportional constant Kl, integral constant KD differential constant α: ′j can be obtained from the differential loop constant control calculation unit 22 by equation (2) Control amount ΔX
By supplying the control voltage V extracted in step 1 to the motor drive unit 23, as is clear from the diagram showing the time change of the control amount ΔXo shown in FIG. 21 can be brought to a near-stop state.

(4) P control and pulse clear When the stage approaches the target position by the PID control described above, the control from the control calculation unit 21 to the motor drive unit 23 is switched to P (proportional) control. That is, as shown in FIG. 3, PID control is performed during the period from time t3 to t4, and after time t4, free vibration of the stage is observed as P control, and information from the laser 11-1 length system is used. Finally, it is confirmed whether the stage is within a predetermined stopping position error. The reason for switching to P control is that the stop control ends more quickly than PID control, and once the stage is within the predetermined stop position error (time t5), the motor drive section is instructed to clear the pulses. In addition, we try to avoid unnecessary movement of the stage due to the influence of extra accumulated pulses.

Although the present invention has been described in detail above, the present invention is not limited to the embodiments described above. For example, although an electron beam lithography apparatus has been described as an example, the present invention can also be applied to an ion beam lithography apparatus.

(Effects of the Invention) As explained above, in the first aspect of the present invention, PID control is performed in the latter half of the stage movement period, and when the stage approaches the L1 position, P control is changed from PID control.

Then, in the second aspect of the present invention, feedforward control is performed in the first half of the stage movement period, and smooth control and PID control are performed in the second half of the stage movement period, so that the target position is approached. At the time, PID control was switched to P control, so it was easy to use 111. This configuration enables high-speed movement of the stage, and also eliminates unnecessary movement when the stage is stopped.
It is possible to realize a moving stage for a drawing device that can perform positioning with high precision.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
FIG. 3 is a diagram showing a speed diagram of the stage, FIG. 3 is a diagram showing a change in control amount ΔXc over time, and FIG. 4 is a diagram showing a configuration example of an electron beam lithography apparatus. 20...Servo motor 21...Moving stage 2
2... Control calculation section 23... Motor drive section 24
... Pulse encoder 25 ... Laser length measurement system 26 ... Position converter

Claims (2)

[Claims] (1) When driving the moving stage on which the drawing material is placed, PID control is performed in the latter half of the stage movement period, and when the target position is approached, the PID control is switched to P control and pulse clearing. A movable stage for a drawing device, characterized in that: (2) When driving the moving stage on which the drawing material is placed, feedforward control is performed in the first half of the stage movement period, and smooth control and PID control are performed in the second half of the stage movement period to approach the target position. When I did,
A drawing device and an 11 moving stage characterized by being configured to switch from PID control to P control.