JPH01216530A - Moving stage for lithography device - Google Patents

Abstract

PURPOSE:To move a moving stage for a lithography device at a high speed with a simple structure, and to provide the moving stage without vibration at the time of stopping by feed-forward controlling it in the former half of a stage moving period, and PID-controlling it in the lower half. CONSTITUTION:A moving stage 21 is moved by feed-forward control at a high speed, and then PID-controlled (proportionally integrated and differentiated) to prevent the stage 21 from vibrating at the time of stopping. The feed-forward control is conducted by predicting in advance the moving mode of the stage 21 and optimally moving it. When a speed diagram waveform is input to the driving input of a control calculator 22, the calculator 22 generates a control voltage V according to the driving input, and applies it to a V/F converter 23. The timing change of a pulse frequency is not formed in a trapezoidal shape but abruptly formed at its rise. The PID control is conducted during the period of falling and stopping the speed of the stage 21, the calculator 22 calculates a control amount while always know the positional information of the stage 21 from a pulse encoder 24 or a laser range measuring system 25, and feeds it back to the driver of a servo motor 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a moving stage for a drawing apparatus, and more particularly to a moving stage for a drawing apparatus 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. 3 is a diagram showing an example of the configuration of an electron beam exposure apparatus. The electron beam (hereinafter simply referred to as beam) Bi emitted from the electron gun 1 is controlled on and off by the blanking electrode 2, and is focused by the subsequent electron lens 3.4.
After being deflected in a two-dimensional direction by a deflection electrode 5, it is irradiated onto 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.

The pattern data for performing beam writing on material 6 is:
It is stored in the external storage device 110. CPU circuit 11
controls the transfer of pattern data stored in the external storage device W110, calculates the amount of stage movement, and the like. Then, the blanking control circuit 12. Control signals are sent to the beam deflection control circuit 13 and the stage movement control circuit 14, respectively. 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. . As a result, a predetermined pattern is exposed (drawn) on the material 6.

In the case of such a beam exposure apparatus, the movement time of the moving stage 7 has a large effect on the drawing throughput. The movable stage 7 is required to move in a short period of time, and it is also necessary that the imaging that occurs when stopped is small.

[Problems to be Solved by the Invention] Conventionally, when driving a moving stage in such an exposure apparatus, the moving stage is driven using a trapezoidal speed diagram as shown in FIG. 4 (a). .

In the figure, the vertical axis is speed and the horizontal axis is time. In this driving method, as for the actual speed change, the rise is slow as shown by the solid line in FIG. Therefore, with such a trapezoidal drive, it is difficult to realize a moving stage capable of high-speed movement.

As described above, the reality is that in conventional exposure apparatuses, a technology for reducing vibrations during high-speed movement or stopping has not been clearly established. Furthermore, in order to realize high-speed movement of the moving stage, it is also necessary that the stage drive mechanism has a simple configuration.

The present invention has been made in view of these points, and
The purpose is to realize a moving stage for an exposure apparatus that has a simple configuration, can move at high speed, and does not vibrate when stopped.

[Means for Solving 11ffl] The present invention for solving the above-mentioned problems includes performing feedforward control in the first half of the stage movement period when driving the movement stage on which the material for beam exposure is placed; The present invention is characterized in that it is configured to perform PID control in the latter half of the stage movement period.

[Operation] Feedforward control is performed during the first half of stage movement, and PID control is performed during the second half.

[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 beam exposure is placed on the moving stage 21.

Reference numeral 22 denotes a control calculation unit that receives drive input for driving the moving stage 21 and position information of the moving stage 21 and generates a control voltage for controlling the movement of the moving stage 21.

As the control calculation section 22, for example, a microcomputer is used.

23 receives the control mTi pressure (■) from the control calculation unit 22,
This is a V/F converter that converts the pulses into corresponding frequency F pulses. The output pulse of the V/F converter 23 is given to the servo motor 20 as a drive pulse. A pulse encoder 24 is attached to the rotating shaft of the servo motor 20 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 length measurement system that detects the position of the moving stage 21; 26 is a position converter that receives the output of the laser length measurement 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 numbing unit 22 as position information. The operation of the device configured as described above will be explained as follows.

In the present invention, first, the moving stage 21 is moved at high speed by feedforward control, and then PID (proportional
Integral/differential) control is performed to prevent vibration of the moving stage 21 when stopped. These two 1lJIj techniques will be explained below.

(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 is input to the drive input of the control calculation unit 22, the control calculation unit 22 generates a control voltage V according to the drive input.
is generated and applied to the V/F converter 23. FIG. 2 is a speed diagram of the drive signal input to the control calculation unit 22 at this time. Unlike the trapezoidal waveform shown in FIG. 4(a), the time change in pulse frequency is not trapezoidal but has a steep rise (approximately twice that of the normal waveform). The plane M (shaded area in the figure) of this velocity diagram is set in advance so that it has the same area as the trapezoid shown in FIG. There is.

In this way, the rise of the waveform is made steep, so
The amount of change with respect to time becomes large, and the moving stage 21 can quickly rise to the desired speed. Also,
The pulse frequency is also lowered early in the second half of the speed diagram to prevent pulses from accumulating internally. This results in
The time required for stopping the moving stage 21 can be shortened.

(2) P[D control This II tall is a control performed during a period when the speed of the moving stage 21 falls and stops. 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 action).

This is a combination of integration (■ operation) and differentiation (D operation), and is called PID control. This PI-DI
l, lj Ill is used, for example, in oil refinery plants, and has been established as a technology that contributes to plant stability.

Therefore, by using Pl and DIlJIIl, vibrations when the stage is stopped can be suppressed.

In the calculation formula, the current position of the moving stage 21 is xt.

When the target position is expressed as a differential equation by xO, the differential value ΔXt is expressed by the following equation.

ΔXt −Xo −Xt ...(
1) The control amount ΔxC output from the control calculation unit 22 using equation (1) is expressed by the following equation.

Δxc −KAXt + (1/Ti)ΣΔXt+T
d (AXt - AXt-1> ... (2) where K: proportional constant Ti H411 minute constant Td; control 1mΔX given by equation (2) from differential constant control calculation section 22
By applying the control voltage (2) corrected by O to the V/F converter 23, the moving stage 21 can be stopped without vibration. Note that the appropriate starting point for PID control is point A in FIG. 2, that is, the point at which the stage movement speed starts to fall in terms of the pulse sending timing.

In the series of operations described above, since the position of the moving stage 21 is input to the control calculation section 22 from the pulse encoder 24 or the laser m-length system 25, the control calculation section 22
The position of the movable stage 21 can be grasped at all times.

Therefore, the movement of the moving stage 21 can also be controlled accurately.

[Effects of the Invention] As described above in detail, according to the present invention, the configuration is simple and high-speed movement is possible by performing feedforward control in the first half of the stage movement period and performing PID control in the second half. , it is possible to realize a moving stage for a drawing device that does not vibrate when stopped.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of a velocity diagram used in the present invention, FIG. 3 is a diagram showing a configuration example of an electron beam exposure apparatus, and FIG. is a diagram showing an example of a conventional moving stage drive waveform (velocity diagram). 20...Servo motor 21...Moving stage 2
2...Control calculation section 23...V/Fl! converter 2
4...Pulse encoder 25...Laser length measurement system 26...Position converter patent applicant Japan Denshi Co., Ltd.
Company Representative Key Person Patent Attorney I
Shimafuji Jigai 1 person

Claims (1)

[Claims] When driving a moving stage on which a material to be drawn is placed, feedforward control is performed during the first half of the stage movement period, and PID control is performed during the second half of the stage movement period. Movement stage for equipment.