JPS5979525A - Electron beam exposure device - Google Patents

Abstract

PURPOSE:To raise accuracy in drawing as well as to reduce drawing time in a device for exposing a sample comprising plural aperture masks and deflectors for beam shaping to make size and shape of electron beam variable by limiting a shape of aperture of a mask to a polygon having at least one interior angle of 180 deg. or more. CONSTITUTION:An electron beam from an electron gun 1 irradiates a first aperture mask for beam shaping 3 through a condenser lens 2 and passes through annular deflection coils for beam shaping 5 and 6 and irradiates a second mask 4. Next, beam after irradiation of the mask 4 is condensed by a condenser lens 7 and passed through coils 10 and 11 to expose a resist arranged on a sample plane 9 through an objective 8. In this constitution, shape of apertures 3a and 4a is limited to a polygon having at least one interior angle of 180 deg. or more and diagonal line of the resist is drawn with parallelogramic beam.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a variable shaped beam type electron beam exposure apparatus.

[Technical background of the invention and its problems] 1. Recently, fine particles have been found in samples such as semiconductor wafers and mask substrates. Various electron beam exposure apparatuses have been developed to form turns. Among these, a so-called variable shaped beam type electron beam optical device, which exposes a sample by varying the dimensions of the electron beam, is attracting attention as the most advantageous for increasing the writing speed.

By the way, when drawing diagonal lines using a variable shaped beam type electron beam exposure device, generally the diagonal lines are subdivided into a collection of rectangles, and each of the subdivided turns is drawn one by one. Therefore, there is a drawback that the drawing time becomes longer.

On the other hand, there are few oblique angles in the second turn of the IC,
Taking note of the relatively large number of diagonal lines at an angle of 45 degrees, a drawing method using a home base type aperture as shown in FIG. 1 has recently been proposed.

With this method, not only a rectangular beam but also a rectangular beam tilted at 45 degrees can be formed by overlapping two aperture masks having apertures in the shape shown in Fig. 1.
Draw time can be significantly reduced.

However, in this type of method, the following (1) to (
There was a problem like 5).

(Since the beam shape with an inclination of 1145 degrees is rectangular, double exposure (area indicated by A in FIG. 2) cannot be avoided when drawing the entire oblique field.

(2) Since it is necessary to uniformly illuminate an area larger than the shaded area in FIG. 1 with the electron beam, it is necessary to increase the emittance of the electron gun.

(3) Because the aperture area is large, two Anno 4
- Beam resolution is degraded due to the space charge effect between the chamask.

(Since a large deflection voltage or current is required to create a beam tilted at 4145 degrees, it is difficult to obtain fast response.

(5) Avoiding double exposure With K, a triangular shape (area indicated by B in FIG. 2) is formed by dividing the pattern into smaller parts at each bent portion of the pattern to be drawn, so that the number of exposures, that is, the drawing time increases.

[Object of the Invention] An object of the present invention is to provide a complete electron beam exposure apparatus that can solve all of the above-mentioned conventional problems (1 to 51) and improve drawing accuracy and shorten drawing time. .

[Summary of the invention]

The gist of the present invention is to completely improve the shape of the aperture and draw diagonal lines with a parallelogram beam.

That is, the present invention provides a variable shaping beam type electron beam exposure apparatus that includes a plurality of beam shaping aperture masks and a plurality of beam shaping deflectors and exposes a sample by changing the size and shape of the electron beam. The aperture shape of the mask is set to be a polygon having at least one interior angle of 180 degrees or more.

〔Effect of the invention〕

According to the present invention, the following effects (1) to (4) can be obtained. Here, the aperture shape is a pentagon with one interior angle of <270V as shown in FIG.

f) The area illuminated by the electron beam can be narrower than in conventional home base type anofactures. For example, up to 2a
In order to obtain a beam size of , it is sufficient to illuminate a circular area with a radius of 6). In contrast, in the conventional method, it was necessary to illuminate a circular area with a radius of 1d(5/3)a.

(2) The deflection voltage or deflection current required to change the beam size and beam shape can be made smaller than before.

In the conventional example, it is necessary to deflect the aperture position by 3a in the horizontal direction and by 2& in the i direction, as shown in FIG. A deflection voltage or deflection current that moves the A/Ya position Ipox by 2a may be sufficient.

(3) The number of triangles to be subdivided can be reduced, and the number of exposures can be reduced.

In the case of the present invention, the pattern shown in FIG. 5fal is completed after three exposures, and triangles to be subdivided cannot be formed. Further, in the pattern shown in FIG. 5(b), there are two triangles (the area indicated by diagonal lines in the figure), and in the pattern shown in FIG. 5(e), there is one triangle. On the other hand, in the conventional example, as shown in Fig. 5(d)
As shown in ~(f), two triangles are formed in all patterns. Therefore, the present invention can reduce the number of exposures,
It is possible to reduce drawing time.

(4) Since the area of the aperture/'P-cha is small, the space charge effect between the two aperture masks can be reduced by 7°, and the beam resolution can be improved.

[Embodiments of the invention]

FIG. 6 is a schematic configuration diagram showing an electron beam exposure apparatus according to an embodiment of the present invention. In the figure, reference numeral 1 denotes an electron gun, and an electron beam emitted from this electron gun is irradiated onto a first beam shaping aperture mask 3 via a condenser lens 2. A second beam shaping aperture mask 4 is arranged below the aperture mask 3, and the aperture mask 3,
A deflection coil (deflector) 5.6 for beam shaping is arranged between the two. The dimensions and shape of the electron beam can be varied by these ano-four-cha masks 3, 4 and deflection coils 5, 6. Here, a.
The apertures Ja and 4a of the matrix masks 3 and 4 are formed in the shape shown in FIG. 3 above.

The electron beam whose beam size and shape have been varied is condensed by a condenser lens 7, and irradiated onto a sample surface 9 via an objective lens 8 to form an image.

As a result, the resist and the like on the sample surface 9 are exposed. In the figure, reference numeral 10.11 indicates a deflection coil for scanning the sample surface 9 with the electron beam.

With such a configuration, by positioning each aperture/arm 3a, 4a of the first and second aperture masks 3, 4 as shown in FIG. 7(a), it is possible to form a rectangular shape. It is possible to create a beam of Furthermore, each a.f.
4. By setting the entire position of a as shown in FIG. 7(b), a parallelogram beam with an inclination of 45 degrees can be made. Therefore, when drawing the ./-turn shown in FIG. 5 fa).

The drawing is completed after three exposures. In addition, when drawing the entire pattern shown in FIG. 5(b), three exposures and
The two subdivided triangles (oblique source part in the figure) are divided into small parallel 4
It is sufficient to perform exposure divided into a set of rectangles. Figure 5(c)
The same applies to the pattern shown in FIG.

According to this embodiment, since the entire parallelogram beam can be created, a pattern including diagonal lines can be drawn with high precision and in a short time. In addition, the extremely f
It also has advantages such as being able to be realized with an easy-to-use 4TI construction.

Note that the present invention is not limited to the embodiments described above. For example, the shape of the armature is not limited to that shown in FIG. 3, but may be as shown in FIGS. 8(a) and 8(b). In this case, as shown in FIG. 5(b)
, (c) also requires three exposures. Further, the shape of the aperture can be changed as appropriate as long as it is a polygon having at least one interior angle of 1809 or more.

Further, the deflector for beam shaping is not limited to a deflection coil, but may be a deflection plate, and the number of the deflectors may be two or more. In addition, various modifications can be made without departing from the gist of the present invention.

[Brief explanation of drawings]

2g1 and 2 are for explaining the conventional example, and Fig. 1 shows the aperture shape, Fig. 2 shows the pattern drawing method, and Figs. 3 to 5 (a) to ff). 3M is a diagram showing the a-zeature shape, FIG. 4(a) is a diagram showing the conventional beam forming state, and FIG. 4(b) is a diagram for explaining the present invention in detail. Figures 5 (a) and 5 (c) show the pattern drawing method according to the present invention, Figures 5 (d) to (f) show the conventional pattern drawing method, and Figure 60 shows the pattern drawing method according to the present invention. A schematic configuration diagram showing an electron beam exposure apparatus according to an embodiment of the invention, FIG. 7(a),
(b) is a diagram showing an example of beam forming by the above embodiment device;
FIGS. 8(a) and 8(b) are diagrams showing modified examples. l...' Hiroko gun s 2 + 7 + 8... Reso, e, 3.4... Beam forming agent A/Piece mask s
3g+4m...Aperture, 5.6...Beam shaping deflection coil (deflector), 9...Sample surface, 10.11
... Scanning deflection coil. Applicant's agent Patent attorney Takehiko Suzue Figure 1
Figure 2 Figure 3 Figure 4 (a) (b) Figure 5 (a) (b) (c) Figure 7 (a) (b) Figure 6 Figure 8 (a) (b)

Claims (1)

[Claims] In a variable shaping beam type electron beam exposure apparatus that is equipped with a plurality of beam shaping aperture masks and a plurality of beam shaping deflectors and exposes a sample by changing the size and shape of the electron beam, the former nQ7. Noa! −
The shape of the chamfer is set to be a polygon having at least one interior angle of 180 degrees or more' (i-Featured electron beam exposure apparatus 4 degrees