JPH04181715A - Beam exposure of pattern - Google Patents

Abstract

PURPOSE:To increase the accuracy of approximation by a method wherein a right-angled triangle pattern having an oblique side with an arbitrary inclination is replaced by a set of rectangular patterns. CONSTITUTION:A short side 2 and a long side 3 are determined by comparing the lengths of two sides that are intersecting at right angles of a right-angled triangle pattern 1 having two sides intersecting at right angles and an oblique side 4, and the right-angled triangle pattern 1 is separated by a plurality of straight lines parallel to the short side 2 to obtain a plurality of trapezoid patterns 5A-5C with constant height. A separated oblique side 4 composing one side of each trapezoid pattern 5A-5C is replaced by a segment of a line which is vertical to the short side 2 and whose length is equal to the height of each trapezoid pattern 5A-5C. The lengths of the upper bottom and the lower bottom of the trapezoid patterns 5A-5C are adjusted to approximate each trapezoid pattern 5A-5C by a rectangular pattern 6A-6C so that the right- angled triangle pattern 1 is approximated by a set of the rectangular pattern 6A-6C. Thus, the accuracy of approximation can be maintained with respect to the right-angled triangle pattern having an oblique side with an arbitrary inclination.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a beam exposure method for a pattern, and particularly to a beam exposure method for a right triangle pattern.

The purpose of this paper is to provide a method for performing beam exposure by accurately approximating a right-angled triangular pattern using multiple rectangular patterns.

A step of determining a short side and a long side by comparing the lengths of two orthogonal sides of a right triangle pattern having two orthogonal sides and a hypotenuse, and dividing the right triangle pattern by a plurality of straight lines parallel to the short sides. to obtain a plurality of trapezoidal patterns of constant height, and replacing the divided hypotenuse forming one side of each trapezoidal pattern with a line segment perpendicular to the short side and having a length equal to the height of each trapezoidal pattern. , and approximating the right triangle pattern with a set of a plurality of rectangular patterns by approximating each trapezoidal pattern with a rectangular pattern by adjusting the lengths of the upper and lower bases of each trapezoidal pattern, and the plurality of rectangular patterns. scanning and exposing a rectangular pattern area in a direction parallel to the short side with a beam, and comprising a pattern beam exposure method in which right triangle pattern beam exposure is replaced with a plurality of rectangular pattern beam exposures. do.

[Industrial application field]

The present invention relates to a pattern beam exposure method, and more particularly to a right triangle pattern beam exposure method.

In recent years, in addition to rectangular patterns consisting of line segments parallel to two orthogonal basic lines, it has become essential for LSI patterns in recent years to have patterns that include line segments at arbitrary angles to the two basic lines. . Any pattern consisting of multiple line segments is
It can be divided into a rectangular pattern consisting of line segments parallel to two orthogonal basic lines and a right triangular pattern consisting of line segments parallel to two orthogonal basic lines and a line segment inclined thereto.

However, current beam exposure equipment that draws LSI patterns draws a right-angled triangular pattern with an arbitrarily inclined hypotenuse by approximating it, and no consideration is given to the accuracy of that approximation. Not yet. Therefore,
It is necessary to improve the accuracy of approximation of a right-angled triangular pattern with an arbitrary slope of the hypotenuse.

[Conventional technology]

FIGS. 2(a) and 2(b) are diagrams for explaining the conventional exposure method, and show that the right triangular pattern 1 is approximated by a plurality of rectangular patterns 6A to 6C. That is.

The right triangular pattern 1 is divided by a predetermined constant width d to create trapezoidal patterns 5A to 5c, and the periphery of the inclined sides of each trapezoidal pattern 5A to 5C is manipulated to approximate each trapezoidal pattern into a rectangle. It is converted into patterns 6A to 6C. After that, the regions of the plurality of rectangular patterns 6A to 6C are exposed.

By the way, in Fig. 2(a), the angle θ between the hypotenuse and the base is 4.
This is the case where the angle θ between the oblique side and the base is larger than 45°. When replacing the hypotenuse with a staircase with a constant width d, if the angle θ is smaller than 45°, the step difference in one staircase is smaller than the width d, and the accuracy of approximating this right triangle pattern with a set of multiple rectangular patterns is good. However, when the angle θ is larger than 45°, the difference in nine steps is larger than the width d, and the accuracy of the approximation deteriorates.

Therefore, simply approximating a right triangle pattern by a set of a plurality of rectangular patterns does not necessarily ensure accuracy of approximation for any angle θ.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned circumstances, and provides a beam exposure method that ensures accuracy of approximation for right-angled triangular patterns having hypotenuses of arbitrary inclinations.

[Means to solve the problem]

FIGS. 1(a) to 1(C) are diagrams for explaining the steps of the example.

The above problem consists of a step of determining short side 2 and long side 3 by comparing the lengths of two orthogonal sides of a right triangle pattern l having two orthogonal sides and hypotenuse 4, and a process of determining short side 2 and long side 3, and dividing the right triangular pattern 1 along straight lines to obtain a plurality of trapezoidal patterns 5A to 5C having constant heights, and dividing the divided oblique side 4 forming one side of each trapezoidal pattern 5A to 5C to the short side 2; , and the length is equal to the height of each trapezoidal pattern 5A to 5C, and the lengths of the upper and lower bases of each trapezoidal pattern 5A to 5C are adjusted to create each trapezoidal pattern 58 to 5.
By approximating C with rectangular patterns 6A to 6C, the right triangle pattern 1 is transformed into a plurality of rectangular patterns 6A to 6.
A step of approximating by a set of C, and the plurality of rectangular patterns 6A
6C by scanning the area with a beam in a direction parallel to the short side 2, and replacing the beam exposure of the right triangle pattern 1 with the beam exposure of a plurality of rectangular patterns 6A to 6C. This is solved by the exposure method. [Function] When a right triangular pattern is approximated by a set of a plurality of rectangular patterns as in the present invention, the step of the staircase corresponding to the hypotenuse of the right triangular pattern is Since it can be kept small, the accuracy of approximating an arbitrary right triangle pattern with a plurality of rectangular patterns is improved.

Since a plurality of rectangular pattern areas are then exposed to beam light, the accuracy of approximation of the exposure pattern to the original pattern is increased.

〔Example〕

FIGS. 1(a) to 1(C) are diagrams for explaining the steps of the embodiment, and the following description will be made with reference to these diagrams.

Referring to FIG. 1(a), the original pattern to be exposed is a right-angled triangular pattern 1, which has two sides parallel to two orthogonal basic lines and an oblique side 4 with respect to the right angle between the two.

The right angle corner of this right triangle pattern l is the origin 0 (0
, 0), and the two sides sandwiching the right angle are in the X direction.

Taken in the X direction, the intersection with the hypotenuse l is A(x+, 0).

Let B be (0, y+).

Comparing Xl and yl, since X+ < y+, line segment OA is short side 2. Know that line segment OB has long side 3.

The length of the short side 2 is 1, for example, 2 μm, and the length of the long side 3 is 1, for example, 4 μm.

A right triangular pattern 1 is divided into a plurality of line segments parallel to the short side 2 at intervals of d. The distance d is 9, for example, 0.2 μm. By this division, the right triangular pattern 1 is divided into trapezoidal patterns 5A, 5B, 5C, etc.

The divided hypotenuse 4 forming one side of the reference trapezoidal pattern 5A, 5B, 5C, etc. in FIG. The upper bases of the trapezoidal patterns 5A, 5B, 5C are lengthened and the lower bases are shortened to form rectangular patterns 6A, 6.
B. Make 6C. If you do that, the rectangular pattern 6
The coordinates of the upper right corner of A are (x+ (x+/y+) (d/2), d), and similarly, the coordinates of the upper right corner of rectangular pattern 6B are (x + (x+/y+) (3d/2), 2 d
), and similarly, the coordinates of the upper right corner of the rectangular pattern 6C are (x+-(xi/y+)(sa/2), 3d).

In this way, the nine trapezoidal patterns 5A, 5B, and 5C are approximated by the rectangular patterns 6A, 6B, and 6C. This approximation is further continued to replace the entire right triangle pattern 1 with a set of a plurality of rectangular patterns.

Referring to FIG. 1(c), the area of the rectangular pattern 6A is exposed with an electron beam having a diameter of 0.2 μm and scanned from the left end to the right end in parallel to the short side 2 (line segment OA). Next, in the same manner, the area of the rectangular pattern 6B is exposed and scanned. Thereafter, exposure scanning is continued in the same manner to complete the exposure of the entire area of one right triangle pattern 1.

In this way, beam exposure can be performed in an approximately right triangular pattern with a step difference smaller than the electron beam diameter.

By applying the above beam exposure method, it is possible to accurately perform beam exposure of a pattern having line segments having arbitrary inclinations with respect to the perpendicular basic line.

In addition, although electron beam exposure was explained in the example,
When using a laser beam instead of an electron beam,
The methods described above are applicable.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to replace a right triangular pattern having a hypotenuse of an arbitrary slope with a set of rectangular patterns, and to improve the accuracy of approximation.

The present invention has the effect of exposing an LSI pattern with high precision, and contributes to reducing the chip size and increasing the density of elements.

[Brief explanation of the drawing]

FIGS. 1(a,) to (C) are diagrams for explaining the steps of the example. FIGS. 2(a) and 2(b) are diagrams for explaining a conventional exposure method. In fig. ■ is a right triangle pattern. 2 is the short side. 3 is the long side. 4 is the hypotenuse. 5A to 5C are trapezoidal patterns. 6A to 6C are rectangular patterns 8 (o, yt) 9 days and months;
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Claims (1)

[Claims] A step of determining a short side (2) and a long side (3) by comparing the lengths of two orthogonal sides of a right triangle pattern (1) having two orthogonal sides and a hypotenuse (4). and dividing the right triangular pattern (1) by a plurality of straight lines parallel to the short side (2) to obtain a plurality of trapezoidal patterns (5A to 5C) with constant heights, each trapezoidal pattern ( Replace the divided hypotenuse (4) forming one side of 5A to 5C with a line segment perpendicular to the short side (2) and having a length equal to the height of each trapezoidal pattern (5A to 5C), and each trapezoidal pattern By approximating each trapezoid pattern (5A to 5C) with a rectangular pattern (6A to 6C) by adjusting the lengths of the upper and lower bases of (5A to 5C), a plurality of right triangle patterns (1) can be created. Rectangular pattern (6A to 6C)
a process of approximating by a set of the plurality of rectangular patterns (6A
~6C) scanning and exposing the area with a beam in a direction parallel to the short side (2); A pattern beam exposure method characterized by replacing the pattern with beam exposure.