JPS6288247A - Electron beam exposure device - Google Patents

Abstract

PURPOSE:To reduce the influence of the ground potential, which results from the proximity of the wall of a vacuum container, by disposing a plurality of electrodes on a circle to constitute an auxiliary deflector, and increasing the distance between the electrodes toward the center of the circle. CONSTITUTION:Prism-shaped electrodes 1A-8A each having an almost triangular cross section are disposed at the same height on a circle to constitute an auxiliary deflector for slightly deflecting an electron beam whose direction is curved by a main deflector in an electron beam exposure device. The distance between the electrodes 1A-8A is decreased outwards as to the circle to reduce the influence of the ground potential, which results from the proximity of the wall of a vacuum container. The distance between the electrodes is increased inwards as to the circle to adjust the disposition of equipotetntial surfaces 9 to make a uniform electric field area nearly fully to the inscribed circle on the electrodes. The uniform electric field area is thus enlarged to diminish the astigmatism caused by the auxiliary deflector.

Description

[Detailed Description of the Invention] [Summary] The cross-sectional shape of the electrodes of the sub-deflector is formed into a triangular shape, a rice ball shape, etc. so that the interval between each electrode becomes wider from the outside of the circumference toward the inside, and the vacuum The influence of the ground potential from the container wall is reduced, and a uniform electric field area within the sub-deflector can be widened, thereby significantly reducing astigmatism caused by the sub-deflector.

[Industrial application field]

The present invention relates to a structure of a sub-deflector that improves astigmatism in an electron beam exposure apparatus.

Currently, electron beam exposure apparatuses are frequently used to form fine patterns having submicron line widths for integrated circuits and the like.

In an electron beam exposure system, the area that can be covered by a large electromagnetic deflection by the main deflector is called the main field, and the sub-deflector, which deflects the electron beam by a small amount after its trajectory is bent by the main deflector, is a high-speed electrostatic deflector. The area that is used and that it can cover is called a subfield.

The size of the main field is the size of the semiconductor chip,
For example, the size of the subfield is about 10III11 squares, and the size of the subfield is about 0.11 squares.

When the exposure of one chip in the main field is completed, the stage carrying the wafer on which many chips are to be formed is moved step by step to expose the chips one after another.

In this case, when the trajectory of the electron beam deflected by the main deflector passes through a location away from the center of the sub-deflector, astigmatism becomes large, so it is desirable that the uniform electric field area within the sub-deflector be large.

[Conventional technology]

FIGS. 2(1) to 2(4) are a perspective view and a sectional view illustrating the electrode structure of a conventional sub-deflector.

FIG. 2 (1) is a perspective view showing the basic structure of electrostatic deflection, with one set of electrodes 11.1 in each of the X and Y directions.
2, and 13.14.

By arranging these electrode pairs so as to be shifted in two directions, interference between electric fields in the X direction and the Y direction is reduced.

The electron beam passes between electrode pairs 11.12 and 13.14, and is deflected in the X and Y directions by the potentials applied to the respective electrode pairs.

In this case, since the positions of the electrode pair 11.12 in the X direction and the electrode pair 13.14 in the Y direction are different in the Z direction, there is a drawback that they cannot be treated equally.

Therefore, if these four poles are arranged at the same height, the electrode pairs will interfere with each other, making it impossible to deflect the light properly.

Therefore, eight poles are usually arranged at the same height and a potential is applied as follows to obtain a uniform electric field.

FIG. 2(2) is a plan view of a sub-deflector in which eight cylindrical electrodes are arranged at the same height.

In the figure, cylindrical electrodes 1 to 8 are arranged on the circumference centered on the origin of the XY coordinates, and each electrode has a potential of +X, (X+Y)/2"", +Y, (-X+Y)/2"", -X, -(X+Y)/2"", -Y, (X-
By providing Y)/2"", a uniform electric field can be obtained in a desired deflection direction on the XY coordinates.

However, since these electrodes are arranged close to the grounded inner wall of the vacuum vessel, they are affected by the ground potential and narrow the uniform electric field area within the sub-deflector.

In order to reduce the influence of the ground potential, the following structure is adopted in which the electrode spacing is narrowed.

Figure 2 (3) shows that the influence of the ground potential is small (so that 8
FIG. 3 is a plan view of a sub-deflector in which thick cylindrical electrodes are arranged at the same height.

In the figure, by using thick cylindrical electrodes, the electrode spacing becomes narrower, but this has the disadvantage that the uniform electric field region is also narrowed at the same time.

In the subsequent figures, 9 schematically shows equipotential lines in the case of X=±XXY=O.

FIG. 2(4) is a plan view of a sub-deflector formed by dividing a cylinder into eight parts by thin cuts so as to reduce the influence of the ground potential.

In this case, the influence of the ground potential can be reduced, but it becomes very difficult to form a uniform electric field within the subdeflector.

[Problem that the invention seeks to solve]

With conventional sub-deflectors, it has been difficult to reduce the influence of ground potential due to the proximity of the vacuum vessel wall and to provide a wide uniform electric field area.

[Means for solving problems]

The solution to the above problem is to have a sub-deflector that performs a small deflection of the electron beam whose trajectory has been bent by the main deflector.
This is achieved by the electron beam exposure apparatus according to the present invention, in which a plurality of electrodes constituting the sub-deflector are arranged on a circumference, and the interval between each electrode becomes wider toward the inside of the circumference from the outside.

For example, when each of the electrodes has a columnar shape with a substantially triangular cross section, the interval between the electrodes can be made wider toward the inner side of the circumference than the outer side.

[Effect]

The present invention reduces the outer spacing of the electrodes arranged on the circumference to eliminate the influence of the ground potential, and widens the inner spacing to adjust the arrangement of equipotential surfaces to approximate the inscribed circle of the electrodes. This allows a completely uniform electric field region to be formed.

〔Example〕

FIGS. 1(1) and 1(2) are cross-sectional views illustrating the electrode structure of a sub-deflector according to the present invention.

FIG. 1 (1) is a plan view of a sub-deflector in which eight prismatic pole electrodes each having a substantially triangular cross section are arranged at the same height.

In the figure, triangular prism electrodes IA to 8A are arranged on the circumference.

In such a structure, the outer spacing between each electrode is narrow, so the influence of the ground potential is reduced (and
Since the electrode spacing becomes wider toward the inside, it is possible to adjust the arrangement of the equipotential surfaces 9 to form a uniform electric field region that covers approximately the entire inscribed circle of the electrodes.

FIG. 1(2) is a sectional view showing a modification of the electrode shape.

As shown in the figure, even if the electrode shape has an approximately triangular trapezoidal cross section due to manufacturing convenience, it is sufficient as long as d≦D/2.

In the embodiment, the cross-sectional shape of the electrode was approximately triangular or trapezoidal close to a triangle, but the cross-sectional shape may be a ball shape, a T shape, or the like instead.

〔Effect of the invention〕

As described above in detail, the sub-deflector according to the present invention can reduce the influence of the ground potential due to the proximity of the vacuum container wall, can widen the uniform electric field region, and can reduce astigmatism caused by the sub-deflector.

[Brief explanation of drawings]

Figures 1 (1) and (2) are cross-sectional views illustrating the electrode structure of a sub-deflector according to the present invention, and Figures 2 (11 to 4) are perspective views and cross-sections illustrating the electrode structure of a conventional sub-deflector. In the figure, IA~8A are electrodes, 9 is equipotential line, 4≦, Wednesday, Sunday R (=Yotoki 7' deflation 2 Yudenki & mini 1
'Head diagram A buttocks 1rQ (1) Puff L lid electrode silk diagram [Next row N thread ↑ Acquisition and front rq N 2 Figure

Claims (2)

[Claims] (1) It has a sub-deflector that performs a small deflection of the electron beam whose trajectory has been bent by the main deflector, and a plurality of electrodes constituting the sub-deflector are arranged on the circumference, and the interval between each electrode is set at the circumference. An electron beam exposure device characterized in that the electron beam exposure device is wider toward the inside than the outside. (2) The electron beam exposure apparatus according to claim 1, wherein each of the electrodes has a columnar shape with a substantially triangular cross section.