JPH0196656A - Charged beam exposure system - Google Patents

Abstract

PURPOSE:To draw a large concentric circular shape while fixing a beam and to prevent drawing accuracy from deteriorating owing to beam deflection by providing a rotary stage which is driven to rotate on a linear positioning stage which is put in linear motion and projecting a converged charged beam on one point on the rotary stage vertically. CONSTITUTION:This device is equipped with the rotary driven stage 10 where a sample 1 is mounted, a charged beam convergence system which projects the generated charged beam on the surface of the rotary stage vertically and also converges it on the specific position, and the linear positioning stage 4 which moves the rotary stage 10 linearly at least in one direction in a plane crossing the projection direction of the charged beam at right angles. The irradiation position of the charged beam is fixed, the rotary stage 10 where the sample is mounted is moved by the linear positioning stage 4 to the specific position, and while the rotary stage 10 is rotated, a circular pattern is exposed. Consequently, the large circular pattern is exposed (including drawing) smoothly in a relatively short time.

Description

DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention A rotary stage that is rotationally driven is provided on a linear positioning stage that moves in a straight line, and a focused charged beam is irradiated perpendicularly to a point on the rotary stage. This makes it possible to draw a large concentric circular shape (or concentric elliptical shape) by fixing the beam, prevent deterioration in drawing accuracy due to beam deflection, and furthermore make drawing time relatively short.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged beam exposure apparatus suitable for exposing mainly circular patterns.

Prior Art and Its Problems A typical example of a charged beam exposure apparatus is an electron beam lithography apparatus. Electron beam lithography equipment was originally developed for the production of VLSI patterns, and is suitable for drawing linear patterns parallel to the XY coordinate system, such as straight lines and rectangles, but it is not suitable for drawing single-curve patterns, especially circular patterns. Not suitable for drawing.

In recent years, there has been a movement to apply electron beam lithography systems to fields other than LSI patterning. For example, the production of Fresnel zones, lens patterns (Fresnel lens patterns, etc.).

Since such a pattern is concentric, if this circular pattern were to be drawn using a conventional electron beam lithography system, the amount of lithography data (position data, ejection amount data) would be enormous. It takes a long time to draw. There are problems such as not being able to obtain a smooth drawing pattern and poor accuracy of the drawing pattern.

These problems will be explained below using the drawings.

FIG. 3(A) shows the state of drawing using a conventional electron beam drawing apparatus, and FIG. 3(B) shows the sample being drawn. In the conventional electron beam lithography apparatus, as can be seen from these figures, after the electron beam is focused (the focusing coil is shown in the figure), the electron beam B is swung back and forth and left and right by the deflection coil 21, and the sample 1 is
Draw the desired pattern by irradiating the dots above that you want to draw. Therefore, for a pattern with two curvatures, there is a problem that it is difficult to obtain a smooth pattern due to the quantization error of the dots.

When drawing a circular pattern using such an electron beam drawing device, the X and Y coordinates (position data) of each drawing point and dose data are required for all points within the drawing range, and the drawing data becomes enormous, and the drawing time inevitably becomes longer.

Furthermore, the conventional electron beam lithography apparatus has a problem in that as the deflection angle of the electron beam is increased, the shape of the electron beam spot is deformed.

FIG. 4 schematically shows changes in the spot shape due to deflection of the electron beam. The spot Pl of the undeflected electron beam B1 is close to a circle.

As the deflection angle increases (electron beam B2), the spot P2 deforms into an ellipse or an egg shape.

The maximum drawing range is the range in which the deformation of the spot does not affect pattern drawing. This maximum drawing range is limited to a very narrow range, such as a square (circle) with a side (or radius) of about 500 μm, and there is a drawback that there is a limit to the size of the pattern that can be drawn.

In order to solve this problem, attempts have been made to draw large area patterns by moving the sample stage. The situation is shown in FIG. Draw a large circular pattern as shown in this figure (in case, divide 9 circular patterns by the maximum drawing range R mentioned above, place the sample on the XY positioning stage, and move the stage to A part of the circle is drawn for each R, and the drawing patterns are connected.

According to this method, in addition to the above-mentioned problem that the exposure time is long due to the dot drawing and the pattern is not smooth, there is also the problem that connection errors occur.

Summary of the Invention An object of the present invention is to provide an apparatus that can expose (including drawing) a large circular pattern smoothly and in a relatively short time.

The charged beam exposure apparatus according to the present invention includes a rotationally driven rotating stage on which a sample is placed, a charged beam focusing system that irradiates a generated charged beam perpendicularly to the surface of the rotating stage and focuses it on a predetermined position, and a rotating The present invention is characterized in that it includes a linear positioning stage that linearly moves the stage in at least one direction within a plane orthogonal to the irradiation direction of the charged beam.

In this invention, the charged beam is simply focused without being deflected,
The sample is irradiated perpendicularly. Therefore, the problem of spot shape deformation due to deflection of the charged beam does not occur.
There is no limit to the exposure range in the sense mentioned above. In this invention, the irradiation position of the charged beam is fixed, the rotary stage on which the sample is placed is moved to a predetermined position by the linear positioning stage, and the circular pattern is exposed while rotating the rotary stage. Continuous and smooth patterns can be created and exposure work time can be shortened. Furthermore, since the radius of the circular pattern is equal to the distance between the rotation center of the rotation stage and the irradiation position of the charged beam, the exposure range is determined by the diameter of the rotation stage or the movement range of the linear positioning stage, making it possible to create extremely large patterns. It becomes possible. Of course, circular patterns of any radius can be drawn. As data for exposure, only the radius data of the circular pattern and the data representing the exposure amount are required, and since the amount of data is reduced, the time required for calculation and reading from the memory is also shortened.

By synchronizing the rotation of the rotary stage and the linear motion of the linear positioning stage, according to the present invention, it is possible to expose not only circular patterns but also various conical cutting curve patterns including ellipses and the like.

DESCRIPTION OF EMBODIMENTS An embodiment in which the present invention is applied to an electron beam lithography apparatus will be described in detail.

FIG. 1 shows an outline of the configuration of an electron beam lithography apparatus. There is a vacuum chamber (writing chamber, exposure chamber) 6, and an electron (charged) beam column 5 is provided in communication with the upper part of the chamber 6. The interior of the chamber 6 and the lens barrel 5 is maintained in a high vacuum state by a vacuum pump.

Inside the vacuum chamber 6, an XY positioning stage (linear positioning stage) 4 is mounted in the X direction (in FIG. 1, the up and down direction is the two directions, and the two mutually orthogonal directions in the plane perpendicular to this are the X and Y directions). , for example ball 13. It is movably arranged by a guide (illustrated path) or the like. This XY stage 4 is moved in the X direction by applying a voltage to the piezo actuator 12 for driving. One end of the piezo element 12 is fixed to one side of the stage 4, and the other end is fixed to a reference fixing member 12a erected on the bottom plate of the chamber 6. Similarly, the stage 4 is supported and transported so as to be movable in the Y direction by a known mechanism including a piezo element (not shown). The amount of movement of the XY stage 4 determines the radius of the circular pattern to be drawn. For this purpose, it is sufficient to move the stage 4 only in the X direction, but in order to correct positional deviation in the Y direction, it is sufficient to move the stage 4 in the Y direction. It is also movable. By using a piezo element, extremely fine transfer control is possible (for example, transfer control of about 0.05 is fully possible), and the transfer range can be quite long.

A rotary stage housing 10 is fixed on such an XY positioning stage 4. If necessary, a second XY positioning stage is further provided on the XY stage 4 so as to be movable in the X and Y directions and transfer controllable, and the housing 10 is fixed on the second XY stage.

In this case, the XY stage 4 performs rough positioning, and the second XY stage performs minute positioning.

A hydrostatic air floating spindle body 7 is provided inside the rotary stage housing IO, and a slight air gap 8 is formed between the housing IO and the spindle body 7.
Air is supplied to the gap 8 by a compression pump or the like outside the chamber 6 as shown by arrow a, and the spindle body 7 is supported in a floating manner so as to be freely rotatable. This is called a static pressure air bearing, and is said to be the bearing that currently provides the highest rotational accuracy (for example, shaft runout accuracy of ±0.05-).

To prevent the air introduced into the air gap 8 from leaking into the chamber 6, a vacuum seal 9 is provided at the top of the one-rotation stage housing lO and the spindle body 7, and the vacuum seal 9 is
The degree of vacuum inside is maintained at a predetermined value. This vacuum seal 9
Although a detailed illustration of this is omitted, the principle is to suck the air in this part to the outside of the chamber 6 as indicated by the arrow.

A drive motor for rotating the spindle body 7 is provided at the lower part of the rotation stage housing lO and the spindle body 7. This drive motor consists of a permanent magnet 14 provided on the spindle body 7 and a coil 11 provided on the housing 10.
It has a structure that does not have connectors such as brushes in order to prevent deterioration of rotation accuracy.

A mechanism (path shown) for fixing the sample 1 is provided on the upper surface of the rotating spindle body 7.

Above spindle body 7. Housing 10. The vacuum seal 9, a static air bearing, a drive motor, and the like constitute a vacuum-sealed static air floating rotation stage.

Inside the lens barrel 5, there are provided an electron (charged) beam B generator (path shown) and a focusing coil 2 for focusing the generated electron beam B and irradiating a spot onto the sample 1 on the rotating stage. . Since the electron beam B is irradiated in the z-axis direction and does not need to be deflected, no deflection coil or the like is provided.

FIG. 2 shows an example of a pattern drawn on the sample 1 using the above-mentioned drawing apparatus. Irradiation position 0 of electron beam B
is fixed as described above.

By moving the XY stage 4, the rotation stage is positioned at an appropriate position. The distance r between the rotation center P of the rotation stage and the irradiation position 0 of the electron beam B becomes the radius of the circular pattern to be drawn.

A circular pattern with a radius of `` is drawn by irradiating a fixed point 0 with an electron beam B while rotating the sample 1 by rotating the rotation stage.The exposure amount of the electron beam is determined by the intensity of the electron beam and the drawing time. .

By moving the XY stage in synchronization with the rotation of the rotary stage and periodically moving its rotation center P, it is also possible to draw patterns such as ellipses.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the invention, 1! FIG. 2 is a cross-sectional view showing the configuration of a child beam drawing device. FIG. 2 shows how a circular pattern is drawn by this electron beam drawing device. FIG. 3 shows how dots are drawn by conventional electron beam deflection, in which (A) is a side view of a part of the apparatus, and (B) is a plan view of a sample. FIG. 4 is a diagram illustrating how the beam spot is deformed by deflection of the electron beam, and FIG. 5 is a diagram illustrating how a large area pattern is drawn by moving the sample stage. 1... Sample. 2... Focusing coil. 4...XY positioning stage 5...Electron (charged) beam column. 6...Vacuum chamber (drawing chamber, exposure chamber). 7...Static air floating spindle body. 8...Air gap. 9...Vacuum seal. lO...Rotating stage housing. 11... Drive motor coil. 12...XY stage drive piezo element. 13...Ball. 14... Permanent magnet of drive motor. B...Electron (charged) beam. Patent applicant Tateishi Electric Co., Ltd. Agent Patent attorney Kenji Ushiku (1 other person) Figure 3 (A) Figure 4 Figure 5m11

Claims (2)

[Claims] (1) A rotating stage that is rotationally driven to place the sample, a charged beam focusing system that irradiates the generated charged beam perpendicularly to the surface of the rotating stage and focuses it on a predetermined position, and irradiates the rotating stage with the charged beam. A linear positioning stage that moves linearly in at least one direction in a plane perpendicular to the direction. Charged beam exposure equipment equipped with (2) A charged beam exposure apparatus according to claim (1), wherein the charged beam focusing system, the rotation stage, and the linear positioning stage are arranged in a vacuum chamber.