JPS63175423A - Electron beam exposure equipment - Google Patents

Abstract

PURPOSE:To reduce the number of shots and to improve a lithography through put by forming a beam by using an aperture formed to match a figure repeated ly presented in a pattern to be of lithography. CONSTITUTION:Variable beams are formed by using 1 plurality of sets of apertures 5 placed on a rodlike supporting plate clamped with a click stop type screw. The plurality of apertures 5 placed on the plate are formed in optimal shapes for the patterns predicted in advance for a lithography. In order to replace all the click stop type apertures 5, an electro-optical barrel may be locally down in vacuum with air locking valves 3, 4, and the apertures of another machine sets can be set in a short time. Thus, the lithography can be formed in a short time by selecting the aperture formed in response to the type and the layer of the pattern to be of the lithography.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an electron beam exposure apparatus that uses an electron beam to form an LSI pattern on a mask or a Si wafer. This invention relates to a variable shaped beam type electron beam exposure apparatus which has been improved to achieve the desired results.

(Prior Art) In recent years, electron beam exposure apparatuses have been increasingly required to be faster and more precise, and variable-shaped beam type electron beam exposure apparatuses have been introduced as a method to meet these demands.

FIG. 4 is a diagram schematically showing the drawing method employed in the standard electron beam exposure apparatus of this system. electron gun 10
The electron beam emitted from the first shaping aperture 102
A statue cut into a rectangular shape.

After being deflected by the shaping deflector 103, it is projected onto the second shaping aperture 104. The AND image of this projected image and the second shaping aperture 104 is further combined with the sub deflector 105 and the main deflector 1.
After receiving the deflection 06, it is projected onto the exposed sample 107 to draw a desired figure. The sub-deflector 105 is used to position a relatively narrow area at high speed and perform five hot shots, and the main deflector 106 is used to position the area to be deflected by the sub-deflector 105. In the figure, a shaping deflector 103. Main deflector 1
Although an electrostatic 108-pole deflector is used as the 06° sub-deflector 105, there are other cases (for example, an electrostatic 4-pole deflector).

(Problems to be Solved by the Invention) In the conventional variable shaped beam type electron beam exposure apparatus, a variable size rectangle or triangle is used as the basic unit of 5 hots. This allows any figure to be divided into rectangular or triangular units,
This is because if a shaped beam is obtained in this unit, it becomes possible to draw any pattern.

For example, Figure 5 shows two types of memory pattern plots, and these patterns are also rectangular and triangular 5h.
You can connect and draw ot.

However, in response to the increasing integration of LSI in recent years, 1
The number of figures to be drawn with a chip has increased dramatically, and the number of 5-hot shaping beams has also increased proportionally. Due to these circumstances, the time required to draw one chip increases dramatically, resulting in a problem that the throughput decreases significantly. For example, memory pattern 2 in FIG. 5(a)
01 is fl! Although the pattern group 202 shown in FIG. 5(b) and FIG. 6 is a repeating unit, it is necessary to decompose it into 5 hots of 69 rectangles and triangles and draw it, which becomes an obstacle to improving throughput. It had become.

The present invention has been made to address these problems.

[Structure of the invention]

Means and operation for solving problem C) In order to solve the above problems, the present invention uses a plurality of sets of apertures mounted on a rod-shaped support plate fixed to a click-stop type screw for variable beam shaping. . This click-stop type screw can change the position of the rod-shaped aperture without breaking the vacuum of the electron optical column, thereby fixing a desired set of apertures at the optical axis position of the electron optical system.

A plurality of apertures placed on a support plate are processed in advance into optimal shapes for each pattern expected to be drawn. The optimal shape for a certain pattern is, for example, the figure itself that repeatedly appears in the pattern, or a combination of basic figures that make up the figure. Further, a plurality of these may be provided in one set of apertures.

Additionally, each set includes shapes for generating other common figures (eg, rectangles and triangles).

To replace all the click-stop apertures, all you need to do is locally vacuum down the electron optical lens barrel by using an air valve.

Therefore, several different sets of apertures can be set in a short time. Therefore, by selecting an aperture created according to the type and layer of the pattern to be drawn, drawing can be done in a much shorter time than before.

(Example) The present invention will be described below using examples. FIG. 1 is a diagram schematically showing an embodiment of the present invention, in which 1 is an electron gun cathode;
2 and 7 are vacuum pumps, 3 and 4 are air valves, 5 is a first forming aperture attached to a click-stop type screw, and 6 is a second forming aperture. Various lenses, deflectors, etc. are omitted from this figure for simplicity.

The airlock valves 3 and 4 are closed when the click-stop type first shaping aperture 5 is completely replaced, but are normally kept open so that the electron beam emitted from the electron gun cathode 1 is shaped by the first shaping aperture 5. The first molded aperture has several sets of openings with different shapes, as shown in the top view of FIG. 2(a). Depending on the type of pattern to be drawn or the layer lζ, one of these
Adjust the click stop screw 5 so that the set is on the optical axis. Here, adjustment is made so that the second aperture from the top in FIG. 2 is at the optical axis position. An enlarged view is shown. When drawing, follow the drawing data.

5 with a deflector (not shown) on the first forming aperture 5.
Position it in any one of the figure-shaped openings. An image of the positioned aperture is projected onto the second shaping aperture. The two-piece molded aperture has a shape as shown in a top view in FIG. 2(b). When the central rectangular aperture is positioned in Figure 2 (B), the image is as shown in Figure 2 (b).
The beams are projected onto various positions of the second shaping aperture as shown by dotted lines in the figure, and rectangular beams with arbitrary lengths or triangular beams with various orientations are formed depending on the positional relationships. When any one of the four peripheral figures is positioned in Figure 2(b), its image is projected onto the center of the aperture in Figure 2(b), that is, the beam is cut by the second shaping aperture. It reaches the sample surface while maintaining the shape of the first aperture image.

FIG. 3 shows a 5-hot color scheme when drawing an M6 pattern using an electron beam exposure apparatus having such a configuration. 1.2, 4, 6, 7, 10 in Figure 3. ．． 11°14.
The figure numbered 17 was obtained by positioning the figure in the central rectangle of the first forming aperture in Fig. 2(a) and projecting its image onto position 4 in Fig. 2(b). 5 shaped beams
Draw hot.

Figures numbered 3 and 13 in Figure 3 are positioned at the top left figure in Figure 2(a), and their images are drawn by 5 hot l with a shaped beam obtained by passing through the second shaping aperture.

Similarly, the figures numbered 5 and 13 in Figure 3 are the upper right figures in Figure 2 (a), and the figures numbered 12 and 16 in Figure 3 are the figures in Figure 2 (a).
The figure numbered 9゜15 in Figure 3 was positioned at the lower left figure in Figure a), and the figure numbered 9゜15 in Figure 2 was positioned at the lower right figure in Figure 2 (a), and the respective images were obtained by passing through the second forming aperture. Draw with a 5-hot shaped beam.

In this way, it was confirmed that the conventional example shown in FIG. 6 required 595 shots to be drawn, but could be drawn in only 17 shots.

(Effects of the Invention) As explained above in the embodiments, according to the present invention, beam formation can be performed using an aperture made in accordance with a figure that appears repeatedly in a pattern to be drawn, so that it is possible to form a beam using Compared to the conventional method, the number of 5-hots is dramatically reduced, and the drawing throughput is significantly improved. Furthermore, compared to the conventional method, there is less need to approximate and draw a diagonal rectangle using a triangle or the like, so data processing time can also be reduced.

According to the present invention, a dedicated aperture for the pattern I to be drawn is prepared in advance, and while being replaced,
It becomes possible to draw with high throughput.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a plan view showing an example of an aperture shape, FIG. 3 is a view showing a memory pattern of the present invention, and FIG. 4 is a variable shaped beam type electron beam. A diagram showing a conventional example of an exposure apparatus, FIG. 5 is a diagram showing division of sho when drawing a memory pattern in the conventional method, and FIG. 6 is a diagram showing a memory pattern. 1... Electron gun cathode, 2... Vacuum pump, 3...
-Air lock valve% 5...Click stop aperture (first molded aperture)%6...Second molded aperture. Agent Patent Attorney Noriyuki Chika Yudo Takehana Kikuyu Figure 3 Figure 4

Claims (1)

[Claims] Multiple sets of apertures are placed on a rod-shaped thin plate, etc., and the plate with the apertures placed on it is fixed to a click-stop type screw and attached to the lens barrel of the electron optical system. , a variable shaped beam type electron beam characterized in that a desired aperture is selected by rotating the click stop screw, and writing is performed using shaped beams of various shapes formed using this aperture. Exposure equipment.