JP3340248B2 - Electron beam exposure method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam exposure apparatus capable of forming an oblique figure with high accuracy without lowering the throughput when drawing a fine oblique figure using a variable rectangular electron beam exposure apparatus. About the method.

[0002]

2. Description of the Related Art Conventionally, when a diagonal figure is drawn using a variable-shaped electron beam exposure apparatus, drawing is performed using a focused electron beam having an intensity profile of the irradiation amount as shown in FIG. For example, see JP-A-5-3659.
As disclosed in No. 5, first, rectangle division is performed. However, since the oblique side cannot be divided into rectangles and becomes non-rectangular, an oblique figure is formed using proximity exposure of the rectangular part closest to the oblique side. are doing. In this case, in order to improve the oblique line accuracy, it is necessary to increase the exposure amount in a portion closest to the oblique side compared to other portions.

[0005] However, drawing requires a large number of rectangular divisions, and further requires a complicated operation such as increasing or decreasing the exposure amount, thus causing a problem that the throughput is reduced. In addition, since the accuracy of oblique lines is determined by the size of the rectangle, it is difficult to draw a figure with low edge roughness, and it has been impossible to form a fine figure with high accuracy.

[0004]

SUMMARY OF THE INVENTION The present invention does not require a large number of rectangular divisions, does not need to adjust the exposure amount, and draws an oblique figure using a variable-shaped electron beam exposure apparatus. This is provided for the purpose of improving the drawing accuracy of oblique lines.

[0005]

To achieve the above object, according to the solution to ## is put to the present invention, when exposing the fine oblique shapes, the electron beam defocused state, the electron beam
Of the irradiated part, the light that can expose the resist film
The irradiation part of the electron beam having the irradiation intensity less than the irradiation intensity
The resist film is exposed by an electron beam so as to overlap .

[0006]

According to the present invention, by the method as described above,
By performing multiple exposure of defocused electron beam,
An oblique figure with high throughput and high accuracy can be formed.

[0007]

1 and 2 are explanatory views of an embodiment of the present invention. When drawing the oblique figure 1 having a line width of 0.5 μm shown in FIG. 2, it is first divided into rectangles 2 of about 0.4 μm . next,
The oblique figure shown in FIG. 1 can be formed by exposing the electron beam resist with the defocused electron beam 3 shifted by 10 μm .

FIG. 3A shows an intensity profile of the irradiation amount of the defocused electron beam. As shown in this figure,
In defocusing, the image formation of the electron beam is shifted with respect to the electron beam resist to be exposed, and the edge slope of the defocused electron beam is smaller than that of the focused electron beam. FIG. 3 (b)
Shows a projection view of the irradiation intensity of the defocused electron beam, and the exposed portion above the electron beam resist exposure threshold is rectangular, and this portion corresponds to the rectangular portion of the focus electron beam, and is below the exposure threshold. Has a circular or elliptical shape.

In this embodiment, since there is no overlap between the rectangular portions, the portion below the exposure threshold value is not originally exposed, but
Since the electron beam has the overlapping portion 4, multiple exposure is performed, and a smooth oblique figure of the edge 5 is obtained by the effect of the proximity exposure.

[0010] In this embodiment, although the division, such as rectangles overlap is not upon block dividing oblique shape, divided as there is an overlap of the rectangular portion by adjusting the current amount of defocus the electron beam Is also possible.

[0011]

As described above, according to the present invention,
In the rectangular division when exposing a diagonal pattern, the division can be performed without overlapping or minimizing the overlap of the rectangular parts, so that an improvement in throughput can be expected, and the exposure of the electron beam resist can be improved. Since multiple proximity exposure of an electron beam equal to or less than the threshold value is used, it is possible to draw a pattern with high accuracy and low edge roughness. Therefore, a high-performance and high-density semiconductor integrated circuit can be manufactured.

[Brief description of the drawings]

FIG. 1 is an exposure forming view of an oblique figure showing a first embodiment of the present invention.

FIG. 2 is a rectangular division diagram of an oblique figure showing a first embodiment of the present invention;

FIG. 3 is an irradiation intensity profile and irradiation intensity projection of a defocused electron beam used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oblique figure 2 Rectangle 3 Defocused electron beam irradiation shape 4 Overlapping part 5 Exposed edge

Claims (1)

(57) [Claims] 1. A variable rectangular electron beam exposure apparatus,
An electronic beam that divides the oblique figure of the resist film into rectangles and draws
In the method of exposing the electron beam, the electron beam is defocused , and the resist film is exposed in the irradiated portion of the electron beam .
The electron having an irradiation intensity not higher than the irradiation intensity
The irradiation part of the beam overlaps and the electron beam
Therefore , an electron beam exposure method comprising exposing the resist film .