JPH05259045A - Electron beam lithography device - Google Patents

Abstract

(57) [Abstract] [Purpose] The throughput is improved by switching the main and sub deflection areas according to the drawing pattern information. A beam emitted from an electron gun 1 is deflected by a sub deflector 7 for deflecting a minute area and a main deflector 8 and is drawn on a sample 9. An electron beam drawing device having a deflection address unit switching function for the main and sub deflectors. [Effect] The throughput can be improved by switching the main and sub deflection units for each precision according to the drawing pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of variably controlling a deflection address unit of a main deflection and a sub deflection in an electron beam drawing apparatus according to the necessity of drawing accuracy.

[0002]

2. Description of the Related Art In an electron beam drawing apparatus, as one method for performing high-speed electron beam deflection with low distortion, a low-distortion magnetic field deflection is used as a main deflector and a high-speed electrostatic deflection is used as a sub-deflector. There is a multi-stage deflection method.

On the other hand, the deflector control is usually digitalized for high reliability. That is, the deflection data becomes an analog value and is amplified by the DAC circuit and becomes an electrical output to the deflector. Therefore, in the multi-stage deflection, a high-resolution DAC is used for the main deflection with a large deflection amount, and a high-speed DAC is used for the high-speed sub-deflector.

The address unit is the minimum unit of beam deflection for drawing, and the deflection field corresponds to the maximum range of the high resolution DAC.

The deflection area of the main deflector (electromagnetic deflector) is determined by the minute area determined from the minimum drawing accuracy.
If there is a portion that requires fine drawing, the deflection address unit (L
It is necessary to reduce SB) and the electrostatic deflection region and the electromagnetic deflection region. In other words, if there is a fine drawing portion even in part, the electromagnetic deflection area is reduced and the deflection field is reduced, which increases the number of stage movements and reduces throughput. On the other hand, if the deflection address unit is increased and the deflection field is increased in order to obtain high throughput, the drawing accuracy of the fine drawing portion cannot be secured, and it is not possible to achieve both high throughput and high accuracy.

[0006]

According to the present invention, the drawing accuracy according to the area required for each part is determined by selecting a deflection address unit, and a drawing pattern including a fine drawing part is drawn with high throughput. .

[0007]

In order to achieve the above object, first, the fineness in each region is judged, and in the low precision region, (1) the LSB of the main deflection region (electromagnetic deflection) is increased.
(The deflection area can be widened so that there is no required accuracy such as 2 times or 4 times.) (2) Raise the LSB of the small deflection area (electrostatic deflection). (Because the area due to electrostatic deflection changes due to (1).) In areas where high accuracy is required, it is necessary to reduce both deflection areas. This switching function ensures the accuracy required for each area and speeds up.

[0008]

In the high precision drawing area, the accuracy is improved by reducing the electromagnetic deflection area. On the other hand, in the low-precision area where there is no fine pattern, the electromagnetic deflection area is widened to the extent that there is no problem of deterioration in accuracy, which causes a reduction in the number of stage movements. By reducing the number of deflections, it is expected that the waiting time after electromagnetic deflection will be reduced.

Through the movement of the stage and the reduction of the electromagnetic deflection waiting time, the throughput can be improved.

[0010]

The details of the present invention will be described below with reference to the illustrated embodiments.

FIG. 1 shows a variable shaped beam type electron beam drawing apparatus. The variable shaped beam system is a system in which the beam emitted from the electron gun 1 is controlled by the shaping deflector 3 at the conjugate cross section of the first rectangular aperture 2 and the second rectangular aperture 4 to obtain an arbitrary rectangular cross section beam. The shaped beam is reduced by the reduction lens 5 and imaged on the sample surface by the objective lens 6. Further, the stage 10 is moved by the drive motor 11, the main deflector 8 and the sub deflector 7 deflect the beam, and an exposure pattern is formed at a desired position on the sample 9. Figure 2
3 shows a block diagram of deflector control. The calculator 14 converts the deflection data into the main deflection DAC circuit 16 and the sub deflection DAC circuit 15
Transfer to. Each DAC circuit outputs deflection data as an analog output, and the main and sub-deflection amplifier circuits 18 and 17 drive the main and sub-deflectors 8 and 7. The main and sub-deflection amplifier circuits 18 and 17 include a sensitivity switching circuit 20 and a sensitivity switching circuit 20 as necessary.
The deflection output is variable at 19. That is, the main and sub deflection address units can be set by this.

FIG. 3 shows an example of changing the main and sub deflection address units. In the entire area of the sample 9, there are portions where the fine pattern is necessary and portions where it is not. At this time, the main and sub deflection regions (LSB) are switched according to the judgment of this pattern. For example, the electromagnetic deflection area is set to 4 mm square in the fine mode, and the electromagnetic deflection area is set to 8 mm square in the high speed mode (area without the fine pattern). It is necessary to enlarge the sub deflection address unit by the enlargement of the main deflection address unit. In this example, the sub deflection region in the fine mode is 40 μm and the sub deflection region in the high speed mode is 80 μm. In this case, the area ratio is 4
By doubling the number of times, the number of stage movements, the number of electromagnetic deflections, etc. are reduced, and throughput can be improved.

The same method can be applied to an electron beam drawing apparatus having a plurality of electrostatic deflectors.

[0014]

EFFECTS OF THE INVENTION Based on the examples given in the embodiments, the throughput will be converted. When the electromagnetic deflection area is increased four times, taking the 16 mm square area as an example, the stage movement frequency is 15 times → 3 times, and the electromagnetic deflection frequency is 1600 times → 400 times. Now, as the throughput conversion condition, (1) drawing time and electrostatic deflection waiting time are ignored. (2) Stage movement time is 50 ms / 4 mm in fine mode, 80 in high-speed mode
ms / 8 mm. (3) The electromagnetic waiting time is 50 μs. Through this, it is expected that the throughput will increase from 0.83 s to 0.26 s, which is about three times higher.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of an electron beam drawing apparatus.

FIG. 2 is a block diagram of a deflector control system having a main / sub deflection area switching function.

FIG. 3 is a diagram showing an example of switching a main deflection region and a sub deflection region.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electron gun, 2 ... First rectangular aperture, 3 ... Forming deflector, 4 ... Second rectangular aperture, 5 ... Reduction lens, 6 ... Objective lens, 7 ... Sub deflector, 8 ... Main deflector, 9 ... Sample 1
0 ... Stage, 11 ... Stage drive motor, 12 ... Main deflection area, 13 ... Sub deflection area, 14 ... Calculator, 15 ... Sub deflection DAC circuit, 16 ... Main deflection DAC circuit, 17 ... Sub deflection amplifier circuit, 18 ... Main Deflection amplifier circuit, 19 ... Sub deflection sensitivity switching circuit, 20 ... Main deflection sensitivity switching circuit.

Claims (1)

[Claims] 1. An electron beam drawing apparatus comprising a stage for positioning and moving a sample, and a deflector for deflecting an electron beam to a desired position on a sample surface.
An electron beam drawing apparatus characterized in that the deflection address unit is controlled as a plurality of values and the deflection address unit is selected according to a drawing pattern.