JP2725927B2 - How to create charged beam drawing data - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, Ru der relates to a method for creating a charged particle beam drawing data used to charged beam exposure apparatus of the vector scanning method of drawing a pattern of a semiconductor integrated circuit as a mask or a semiconductor wafer .

[0002]

2. Description of the Related Art When a pattern is formed by charged beam exposure, a design figure obtained by design is generally represented by a polygon, but charged beam drawing data is represented by a rectangular and trapezoidal basic figure. Therefore, when a pattern is formed by charged beam exposure, design data of a design figure cannot be used as it is as charged beam drawing data. Also, if there is an overlap in the figures based on the charged beam drawing data, multiple exposure is performed, and it is necessary to perform a process of removing the overlapped charged beam drawing data. Therefore,
Conventionally, the design data is subjected to an overlap elimination process to remove data that results in multiple exposures, and then the polygonal design figure is divided into a rectangle and a trapezoid that are charged beam drawing data.

[0003]

When a design figure based on the design data is divided into basic figures (hereinafter simply referred to as basic figures) of the charged beam drawing data after performing the overlap removal processing on the design data, Conventionally, emphasis has been placed on the processing speed, so when a polygonal design figure 1 as shown in FIG. 3A is given, FIGS. 3B and 3C
As shown in the figure, the polygon is uniformly divided vertically or horizontally from each vertex 1a. In this case, when divided in the horizontal direction, as shown in FIG.
b to 1f are generated many times, and the width is 0.5 μm depending on the design figure.
An elongated figure of m or less may occur. In the actual drawing stage, these figures are further divided and drawn in drawing units of the drawing apparatus. However, there is a problem that extremely fine figures deteriorate the quality of the drawing pattern. On the other hand, in the example of FIG. 3, it is considered that the division method of FIG. 3B should be selected. However, there are various design figures of the actual semiconductor integrated circuit, and it is better to divide in the vertical direction. Also, there is a problem that graphics which should be divided in the horizontal direction coexist and the processing becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a charged beam drawing data creating method capable of improving the quality of a drawing pattern by eliminating figures that degrade the quality of the drawing pattern. The purpose is to get.

[0005]

SUMMARY OF THE INVENTION A charged beam drawing data creating method according to the present invention comprises the steps of dividing a design figure in a vertical direction and a horizontal direction to form a plurality of basic figures; Calculating the aspect ratio, which is the ratio of the height to the width, and determining the average of these aspect ratios, and determining the direction in which the average of the obtained aspect ratios is closer to 1 as the dividing direction. It is a thing.

[0006]

The present invention eliminates the invention of an elongated basic figure,
The quality of the drawing pattern can be improved.

[0007]

【Example】

Embodiment 1 FIG. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart schematically illustrating a method for creating charged beam drawing data according to the present invention. FIG. 2 is an explanatory diagram illustrating an embodiment of the present invention using simple numerical examples. () Is a view obtained by dividing the design figure in the vertical direction, and (C) is a view obtained by similarly dividing the design figure in the horizontal direction.

In FIG. 1, a design figure is inputted in step S1, and the design figure is divided in a vertical direction in step S2 to form a basic figure. The aspect ratio (height of figure / width of figure) is calculated for each of the basic figures divided in step S3, and the average value is calculated. Similarly, in step S4, the design figure is divided in the horizontal direction to form a basic figure, and in step S3, the aspect ratio and the average thereof are calculated. Next, in step S5, the average values of the aspect ratios in the vertical direction division and the horizontal direction division are compared, and the direction in which the average value of these aspect ratios is closer to 1 is selected and determined to determine the design graphic division direction. . Here, an aspect of 1 means that the height of the figure is the same as the width of the figure. That is, it indicates that there is no elongated figure. The aspect ratio is smaller than 1 when the figure is horizontally long and larger than 1 when it is vertically long.

The above-described charged beam writing data creation method of the present invention will be described below with reference to FIG. 2 using numerical examples. First, a design figure 2 as shown in FIG.
Considering the case where the design figure 2 is divided in the vertical direction from the vertex 2a, the design figure 2 has a rectangular basic figure 2b having a width w1 and a height h1 and a width w2, as shown in FIG. It is divided into a rectangular basic figure 2c having a height h2. The average of the aspect ratio in the case of FIG.

(H ₁ / w ₂ + h ₂ / w ₂ ) / 2

## EQU1 ## Similarly, considering the case of dividing horizontally, a rectangular basic figure 2 as shown in FIG.
d, 2e, and the average value of the aspect ratio is

(H ₂ / w ₃ + h ₄ / w ₄ ) / 2

## EQU1 ## In general, when divided into n basic figures,

(H ₁ / w ₁ +... + H _n / w _n ) / n

In this case, the aspect ratio may be calculated. Now, w1 = 2 μm, w2 = 3 μm, h1 = 1.5 μm,
If h2 = 2.4 μm, w3 = w1 + w2, h3 =
Since h1, w4 = w2, h4 = h2-h1, the average value of the aspect ratio is 0.775 in the case of the vertical division shown in FIG. 2B and 0.2 in the case of the horizontal division shown in FIG. The average value of the aspect ratio of the division is closer to 1. Therefore, in the case of a graphic as shown in FIG.
Should be divided.

[0016]

As described above, according to the present invention, a design graphic is divided into a vertical direction and a horizontal direction to form a plurality of basic figures, and the ratio of the height and width of each formed basic figure is determined. The method includes a step of calculating a certain aspect ratio and calculating an average value of these aspect ratios, and a step of determining a direction in which the obtained average value of the aspect ratio is closer to 1 as a division direction. This has the effect of eliminating the occurrence of deteriorating figures and improving the quality of drawing patterns.

[Brief description of the drawings]

FIG. 1 is a flowchart schematically illustrating a charged beam drawing data creation method according to the present invention.

FIG. 2 is an explanatory diagram showing a numerical example of the embodiment of FIG. 1;

FIG. 3 is an explanatory diagram illustrating a conventional method of dividing a design graphic.

[Explanation of symbols]

 2 Design graphics 2b, 2c, 2d, 2e Basic graphics w1 to w4 Width of basic graphics h1 to h4 Height of basic graphics

Claims (1)

(57) [Claims] 1. A step of dividing a design graphic in a vertical direction and a horizontal direction to form a plurality of basic graphics, and calculating an aspect ratio which is a ratio of a height to a width of each of the formed basic graphics. A method for generating charged beam drawing data, comprising: a step of obtaining an average value of an aspect ratio; and a step of determining a direction in which the obtained average value of the aspect ratio is closer to 1 as a division direction.