JPS59119831A - Method for splitting of pattern in charged particle beam exposure - Google Patents

Abstract

PURPOSE:To accomplish the sufficient accuracy required for a pattern without having restriction of minimum drawing unit patterning by a method wherein a triangular pattern and a paralellogram pattern are removed from patterns containing diagonal sides, a straight line is extended from the shorter side of the two sides interposing a concaved points between them starting from each concaved point of the remaining region, and the remained region is divided. CONSTITUTION:The two end points of the diagonal side are designated as points A and B, and a straight line is drawn in the direction excluding the oblique side facing from the point B toward the internal part of a pattern 3, to be more precise, in the direction wherein the scanning direction of an exposure beam and the direction authogonally intersecting with the scanning direction, and this point of intersection is designated as C. The points A, B and C form a triangle, and a triangular pattern 31 is obtained. This triangular pattern 31 is removed from the pattern 3, and the remaining tetragons B, C, D, E, F and G are splitted. At this point, among the apexes of said tetragons, attention is directed to the concaved point, nd the two sides pinching said concaved point, namely the side BC which is shorter than DC, is extended and the point-intersecting with the side EF is designated as H, the region left by the straight line CH is divided into tetragonal patterns 32 and 33.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical field of the invention The present invention provides a method for exposing each pattern of a complex shape using a charged particle beam exposure method such as an electron beam exposure method or an ion beam exposure method. The present invention relates to an improvement in a figure division method in a charged particle beam exposure method, in which the sides are divided into triangles, quadrilaterals, parallelograms, etc. whose sides include the scanning direction of an exposure beam and a direction perpendicular to the scanning direction. In particular, the present invention relates to an improvement in which the number of division patterns is reduced to reduce the number of division steps, and the invention is not limited by the minimum drawing unit figure.

(2) Background of the technology, conventional technology, and problems In charged particle beam exposure methods such as electron beam exposure methods and ion beam exposure methods, a charged particle beam having a minute width is used to scan this beam. while adjusting the irradiation amount according to the desired pattern information and irradiating the sample.
Before exposing the sample surface to a desired pattern, it is essential to divide the pattern so that it can be drawn most efficiently using the exposure equipment currently in use. This is because exposure apparatuses in the prior art have various functional limitations.

Therefore, in the case of a pattern having a side (hereinafter referred to as the hypotenuse) extending in the scanning direction of the exposure beam and the direction perpendicular to the scanning direction, for example, as shown in FIG. The rectangle pattern 1
1 and a triangular pattern 12, and the triangular pattern 12 was further divided into minute rectangular patterns having extremely small short sides as shown in the figure.

By the way, when the pattern width is very thin, such as 0.1 to 0.2 μIn, it is easily affected by the beam sag of the electron beam exposure device, and especially in the case of a rectangular beam, the current density distribution does not have an ideal step-like shape but a beam edge. It has a droop width.

As a result, the area of the drawn figure becomes thick (if the area changes, the charge distribution becomes uneven in the parts where these figures are connected, the pattern is likely to break, and the quality of the formed pattern deteriorates. Therefore, the minimum size of the figure that can be drawn is Dimensions exist.

This is called the minimum unit figure, and when dividing the pattern,
Naturally, this restriction applies. When exposure is performed with a pattern smaller than this minimum drawing unit figure, the quality of the pattern deteriorates.

For example, when dividing pattern 2 as shown in Figure 2,
When divided vertically into two rectangles, that is, pattern 21 and pattern 22 (Fig. 2(a)), pattern 2
If the short side of 2 is 0.1 to 0.2 .mu.In or less, the pattern quality after drawing is reduced due to the restriction of the minimum drawing unit figure. On the other hand, if the same pattern 2 is laterally divided into two rectangles, that is, a pattern 21' and a pattern 22' (FIG. 2(b)), it becomes possible to draw a pattern with high precision. In other words, whether or not the minimum drawing unit figure is constrained often depends on the method of dividing the pattern.

In general, the number of patterns used to manufacture integrated circuits, etc. is enormous, and their shapes are complex, so the number of steps required to divide a pattern with a hypotenuse like the one mentioned above is extremely large. Furthermore, since the step of dividing a pattern so as to avoid the restriction of the minimum drawing unit figure is also cumbersome, there is a strong demand for a figure dividing method in a charged particle beam exposure method that is more advantageous for the process.

(3) Purpose of the Invention The purpose of the present invention is to meet this demand, and to provide a method for dividing a pattern including a hypotenuse, which reduces the number of man-hours required for dividing a figure, and which is free from the constraints of the minimum drawing unit figure. It is an object of the present invention to provide a figure division method in a charged particle beam exposure method, which has no advantages, is simple, and can realize necessary and sufficient pattern accuracy.

(4) Structure of the Invention The above object is to provide an oblique side that extends in a direction excluding the scan direction of the exposure beam and a direction orthogonal to the scan direction among the sides forming the outline of the exposure pattern, from both ends of the oblique side. A straight line is drawn in a direction perpendicular to the scan direction of the exposure beam and the +iif scan direction, a triangle or parallelogram formed by the straight line and the hypotenuse is removed from the exposure pattern, and the remaining area is A figure in a charged particle beam exposure method, characterized in that the remaining area is divided by drawing a straight line that is an extension of the shorter side of the two sides sandwiching the recessed point from each recessed point of the area. This is achieved by a dividing method.

In order to reduce the number of steps required to divide a pattern that includes a hypotenuse, it is possible to separate a triangular pattern and a parallelogram pattern from a pattern that includes a hypotenuse, and draw these patterns as one pattern without dividing them any further. Just do it. Therefore, in the present invention, the triangular pattern and the parallelogram pattern are removed from the pattern including the hypotenuse, and the remaining area not including the hypotenuse is further divided so as not to be subject to the restriction of the minimum drawing unit figure. It is something.

Hereinafter, the steps shown in the above configuration will be explained in further detail with reference to FIGS. 3(a), (b), and (C1).

First step: Before dividing the pattern 3 including the hypotenuse, first, set the points at both ends of the hypotenuse to A, respectively, as shown in FIG. A straight line parallel to the direction not including the hypotenuse of C, that is, the scanning direction of the exposure beam and a direction perpendicular to this scanning direction, is drawn toward C, and the intersection point is C. Points A, 1: 1, C form a right triangle, and the triangular pattern 31 shown with parallel hatched areas is ? II (Fig. 3 (1)+).

Second step: The above three-jrt pattern 31 is excluded from pattern 3, and the remaining polygon 13 CD J-; FG is further divided. Now, focus on the four points C among the vertices of this polygon, and divide the remaining area by sandwiching this concave point C into a pattern 32 and a pattern 33 made of quadrilaterals. (Figure 3 (C)).

According to the above process, pattern 3 can be easily drawn into pattern 31 with less man-hours without generating the minimum drawing unit figure.
．． 32, and d33.

However, in the case of pattern 4 shown in FIG. 4 [a], that is, when the triangular pattern 41 obtained based on the above process is smaller than the minimum drawing unit figure and cannot be drawn, only the diagonally shaded part is The dividing method was changed, and as shown in FIG. do it.

(5) Embodiments of the Invention A figure dividing method in a charged particle beam exposure method according to an embodiment of the present invention will be explained below with reference to the drawings, and the structure and unique effects of the present invention will be clarified. - As an example, a method of dividing a pattern 5 including an oblique side as shown in FIG. 5 will be described.

As the first step, a triangular pattern 51.52 is applied to the oblique side.
．． 53 (areas indicated by parallel hatching in FIG. 5(a)). Subsequently, as a second step, the above-mentioned triangular patterns 51, 52, and 53 are removed from pattern 5, and the recesses ■, J,
Then, by focusing on L, M, and N (see FIG. 5(b)) and dividing them as shown by broken lines in the figure, a rectangular pattern 54, 55, 56, 57, 58 is obtained, and pattern 5 is obtained. Complete the division process.

According to the above process, in a pattern with a complex shape including a hypotenuse, by separating the hypotenuse part as a triangular pattern, the man-hours are reduced, the number of divided patterns is also reduced, and the size is smaller than the minimum drawing unit figure. This has advantages such as being able to effectively prevent the occurrence of small patterns.

(6) As described in the detailed description of the invention, according to the present invention, in a method for dividing a pattern including a hypotenuse, the number of man-hours required for dividing a figure is reduced, and there is an advantage that the figure is not limited by the minimum drawing unit figure. It is possible to provide a figure division method in an 11:I heavy particle beam exposure method, which is simple and can achieve necessary and sufficient pattern accuracy.

[Brief explanation of the drawing]

1st L! g, 2nd V(a), and fbl are diagrams for explaining the pattern part''j method in the prior art;
bad (al, fbl, (C) and 41st (al, (bl
is used for detailed explanation of the present invention, and FIG. 5(a)
), fbl are diagrams for explaining a figure division method in a charged particle beam beam method according to an embodiment of the present invention. 1.2.3.4.5... Pattern, 11.12
．． 21.21', 22, 22', 31.32.33.
41.42.43.44.45.51.52.53.5
4.55.56.57.58... Divided pattern, C, I, J, L, 84, N... Concave points.

Claims (1)

[Claims] Among the sides forming the outline of the exposure pattern, for the oblique side extending in a direction other than the scanning direction of the exposure beam and the scanning direction (a direction perpendicular to the scanning direction), from both ends of the oblique side A straight line is drawn in a direction perpendicular to the self-scanning direction, a triangle or parallelogram formed by the straight line and the hypotenuse is removed from the path light pattern, and each of the remaining areas is A graphic needle in a charged particle beam exposure method, characterized in that the remaining area is divided from a concave point by extending the shorter side of the two sides sandwiching the concave point and making a straight line. How to fit.