JP3457874B2 - Electron beam lithography system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam drawing apparatus for drawing an electron beam emitted from an electron beam column on a surface to be drawn by deflection, and particularly to a reflection generated from the surface to be drawn during drawing. The present invention relates to an electron beam drawing apparatus which is improved to suppress deterioration of drawing accuracy caused by electrons.

[0002]

2. Description of the Related Art In an electron beam drawing apparatus that draws an electron beam emitted from an electron beam column on a drawing surface by deflecting and irradiating the drawing surface, when the drawing surface is irradiated with the electron beam, Reflected electrons are generated from the surface to be drawn.

The reflected electrons strike the member on the electron beam barrel side facing the surface to be drawn and are reflected, and irradiate the surface to be drawn again. Then, there is a problem that this causes deterioration of drawing accuracy.

Therefore, conventionally, a reflection suppressing plate made of a material having a small reflectance, for example, beryllium (Be) is attached to the electron beam lens barrel side to suppress the amount of reflected electrons returning to the surface to be drawn. It was

[0005]

However, recently,
Increasingly high precision drawing is required, and the conventional antireflection plate has become insufficient. The present invention has been made based on the above circumstances, and provides an electron beam drawing apparatus capable of more reliably suppressing deterioration of drawing accuracy due to backscattered electrons generated from a surface to be drawn and capable of high-precision drawing. Has an aim.

[0006]

As a first means for achieving the above object, the present invention provides an electron beam which is drawn by deflecting and irradiating an electron beam emitted from an electron beam column onto a drawing surface. In the drawing apparatus, the reflected electrons generated from the drawing surface at the time of drawing and taken into the electron beam column side do not return to the drawing surface from the periphery other than a portion slightly larger than the deflection region of the electron beam. A non-magnetic backscattered electron shield means that is grounded is provided.

According to the electron beam drawing apparatus of the first means, the reflected electrons generated from the surface to be drawn at the time of drawing and taken into the electron beam lens barrel side hit the member on the electron beam lens barrel side. Although the light is reflected and returns to the surface to be drawn to irradiate the surface to be drawn, most of the reflected electrons reflected are collided with the means for shielding reflected electrons. Since the backscattered electron shielding means is non-magnetic and connected to the ground, the backscattered electrons colliding with the backscattered electron shielding means are absorbed by the backscattered electron shielding means and are prevented from returning to the drawing surface. As a result, deterioration of drawing accuracy is suppressed to a small level, and high drawing accuracy is obtained.

Further, according to the electron beam drawing apparatus of the second means, the reflection electron shielding means is provided on the tip side of the electron beam lens barrel, and the electron beam emitted from the electron beam lens barrel is deflected. The electron beam transmitting hole slightly larger than the area, the non-magnetic shielding plate for shielding the periphery of the electron beam transmitting hole, and the means for connecting the non-magnetic shielding plate to the ground, the drawing surface at the time of drawing The reflected electrons generated from the electron beam transmitting hole are taken into the electron beam lens barrel side, and the reflected electrons taken into the electron beam lens barrel side are drawn from the periphery other than the electron beam transmitting hole. It is configured not to return to.

According to the electron beam drawing apparatus of the second means, the reflected electron shielding means can be simply and inexpensively constructed, and the reflected electrons generated from the drawing surface at the time of drawing are taken in from the holes of the nonmagnetic plate. Then, it hits a member on the electron beam lens barrel side and is reflected, and tries to irradiate the drawing surface by returning to the drawing surface side, but since the periphery of the hole is closed in the non-magnetic plate,
Most of the reflected electrons reflected are collided with the non-magnetic plate. Since the non-magnetic plate is connected to the ground, the reflected electrons that collide with this are absorbed by the non-magnetic plate and are prevented from returning to the drawing surface. As a result, the deterioration of drawing accuracy is suppressed to a small level,
High drawing accuracy can be obtained.

Further, according to the electron beam drawing apparatus of the third means, the reflection electron shielding means adjusts the position of the non-magnetic shielding plate in the optical axis direction of the electron beam lens barrel. Since the directional position adjusting means is provided, a larger number of reflected electrons can be taken in by the smaller electron beam transmitting hole.

Further, according to the electron beam writing apparatus of the fourth means, the reflected electron shield means adjusts the position of the non-magnetic shield plate in a plane perpendicular to the optical axis of the electron beam lens barrel. Since it is provided with the optical axis orthogonal direction position adjusting means, more reflected electrons can be taken in by a smaller electron beam transmitting hole.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. In the figure, 1
Is a main body of the apparatus that forms the drawing chamber 2, and an electron beam lens barrel 3 is attached to the upper part thereof.

An XY stage 4 is arranged in the drawing chamber 2, and a sample 5 as a material to be drawn is set on the XY stage 4. The electron beam 6 is emitted from the electron beam column 3 toward the upper surface of the sample 5, that is, the drawing surface 5A.

Further, the tip side of the electron beam lens barrel 3 (see FIG. 1)
On the lower end side), the reflected electrons generated from the surface to be drawn 5A at the time of drawing and taken into the electron beam lens barrel 3 side are outside the area slightly larger than the deflection area of the electron beam 6. Grounded non-magnetic backscattered electron shielding means 100 is provided so as not to return to the drawing surface 5A.

The backscattered electron shielding means 100 is provided at the tip end side of the electron beam lens barrel 3 and has an electron beam transmission hole 17 slightly larger than the deflection area of the electron beam 6 emitted from the electron beam lens barrel 3. However, the non-magnetic shield plate 7 is a non-magnetic shield member that shields the periphery of the electron beam transmission hole 17, and the earth connection means 20 that connects the non-magnetic shield plate 7 to the earth 16. There is.

The non-magnetic shield plate 7 is substantially cup-shaped or dish-shaped with its upper part open in FIG. 1, and its original end side (upper end side in FIG. 1) is arranged perpendicular to the optical axis of the electron beam lens barrel 3. The compressed lower surface of the ring-shaped member 8 is pressed by the compression spring 9 and is movably held along the lower surface of the ring-shaped member 8.

The non-magnetic shield plate 7 has two first drive units 1 which are arranged on the lower surface side of the ring-shaped member 8 and at positions different by 90 degrees with respect to the optical axis.
By the optical axis orthogonal direction position adjusting means 22 having 0 and 10, in the plane perpendicular to the optical axis of the electron beam lens barrel 3, that is, in the direction orthogonal to the optical axis of the electron beam lens barrel 3, In other words, it can be moved in the front-rear and left-right directions (X and Y directions), so that it can be adjusted to an optimum position.

Further, the non-magnetic shield plate 7 is moved by the optical axis direction position adjusting means 24 for adjusting the position in the optical axis direction of the electron beam lens barrel 3, that is, the optical axis direction of the electron beam lens barrel, in other words, the vertical direction. The position can be adjusted in the direction (Z direction).

The optical axis direction position adjusting means 24 has the following construction. That is, the ring-shaped member 8 is attached to the apparatus main body 1 so as to be movable in the optical axis direction by a plurality of guide bars 11 extending parallel to the optical axis of the electron beam lens barrel 3, and a plurality of tension springs 12 are used to move the ring-shaped member 8 to the optical axis direction. Is given an upward bias.

As shown in FIG. 1, the plurality of guide bars 11 have slopes at their upper ends, and these slopes respectively contact the slopes of the wedge members 13 having a pair of slopes. Has been done. These plural wedge members 1
3 are connected by a connecting member 14, are attached to the apparatus main body 1 so as to be integrally movable in the left-right direction in FIG. 1, and are positioned at a desired position by a second drive device 15 attached to the apparatus main body 1. It is like this.

Further, the non-magnetic shield plate 7 is connected to the earth 16 via the ground connection means 20, that is, the ring-shaped member 8 for supporting the non-magnetic shield plate 7, the guide bar 11, the wedge member 13 and the apparatus main body 1. It is electrically connected.

Further, the non-magnetic shield plate 7 has a tip portion 7A.
(Lower end in FIG. 1) is the sample surface 5A which is the surface to be drawn.
The front end portion 7A is formed with an electron beam transmission hole 17 through which the electron beam 6 passes, as shown in an enlarged view in FIG.
The electron beam transmission hole 17 is formed slightly larger than the area where the electron beam 6 is deflected during writing.

On the front end side of the non-magnetic shield plate 7, reflected electrons 6 from the sample surface 5A taken in from the electron beam transmission hole 17 are provided.
A backscattered electron detector 18 for detecting A is attached. Next, the operation of the present apparatus thus configured will be described.

When the electron beam 6 emitted from the electron beam lens barrel 3 is applied to the sample surface 5A during drawing, reflected electrons 6A are generated as shown in FIG. This backscattered electron 6A
Are taken into the electron beam lens barrel 3 side from the electron beam transmission hole 17 of the non-magnetic shield plate 7 arranged so as to face the sample surface 5A.

The amount of backscattered electrons 6A taken from the electron beam transmitting hole 17, that is, the light receiving rate g is expressed by the following equation. Here, X is the distance from the irradiation position of the electron beam 6 to the end of the electron beam transmission hole 17, L is the distance between the sample surface 5A and the tip 7A of the non-magnetic shield plate 7, and α is the electron beam transmission. This is the reflection angle of the reflected electrons 6A taken in by the hole 17.

[0026]

[Equation 1]

As is clear from this equation, if the reflection angle α of the reflected electrons 6A to be taken in is close to 180 °, the light receiving rate g
Is close to 1 or 100%. For that purpose, the distance X from the irradiation position of the electron beam 6 to the end of the electron beam transmission hole 17 is large, and the distance L between the sample surface 5A and the non-magnetic shield plate 7 is small. good.

However, the distance X is equal to the electron beam transmission hole 17
In order to suppress the amount of the reflected electrons 6A taken in from the electron beam column 3 side and returning to the sample surface 5A to be small, the size is slightly larger than the region where the electron beam 6 is deflected at the time of drawing as described above. Preferably, it is formed into

The present device detects the amount of backscattered electrons 6A taken in from the electron beam transmission hole 17 by the backscattered electron detector 18, and the second drive unit so that the amount becomes equal to or more than a predetermined value. The position of the wedge member 13 is adjusted by 15, and the non-magnetic shield plate 7 is positioned in the optical axis direction (Z direction) via the guide bar 11 and the ring-shaped member 8.

The amount of backscattered electrons 6A is detected by the backscattered electron detector 18 while deflecting the electron beam 6 emitted from the electron beam column 3, and the amount of backscattered electrons 6A at the front and rear deflection ends is substantially equal. So that the first drive devices 10 and 10 position the non-magnetic shielding plate 7 in a plane perpendicular to the optical axis in the directions orthogonal to the optical axis (X and Y directions).

In this way, if α is set to about 170 °, 90% or more of the reflected electrons 6A can be taken in from the electron beam transmitting hole 17. Electron beam transmission hole 17
The backscattered electrons 6A taken in from are reflected by the electron beam lens barrel 3 side and try to return to the sample surface 5A side, but the periphery of the electron beam transmission hole 17 is shielded by the nonmagnetic shield plate 7. , Most of the backscattered electrons 6A are non-magnetic shield 7
Hit

Since the non-magnetic shield plate 7 is connected to the earth 16 by the earth connecting means 20 described above, it is absorbed by the non-magnetic shield plate 7 and prevented from returning to the sample surface 5A.

The backscattered electron detector 18 is connected to the backscattered electron 6
Since it has a function of absorbing A, the backscattered electron detector 18 is attached so as to close all the openings on the base end side of the non-magnetic shield plate 7 leaving the passage 19 for the electron beam 6 or the backscattered electron 6A. It is desirable to close it with a non-magnetic shield plate 77 that absorbs.

In the above-described embodiment, the backscattered electron detector 18 detects the amount of backscattered electrons 6A taken from the electron beam transmission hole 17 to detect the position of the non-magnetic shield plate 7, that is, the electron beam transmission hole 17. Although an example in which the position is more surely determined has been shown, the non-magnetic shield plate 7 is not limited to this, and even if it is fixedly attached to a predetermined position, an effect which has not been obtained conventionally can be obtained.

Further, it is needless to say that the mechanism of the optical axis orthogonal direction position adjusting means 22 and the optical axis direction position adjusting means 24 of the non-magnetic shield plate 7 is not limited to the above-mentioned embodiment, and various modifications can be made. In addition, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0036]

As described above, the present invention has the following effects. According to the electron beam drawing apparatus of claim 1, in an electron beam drawing apparatus that draws by deflecting and irradiating an electron beam emitted from an electron beam lens barrel onto the drawing surface, the electron beam drawing apparatus generates from the drawing surface at the time of drawing, In addition, a grounded non-magnetic backscattered electron shield means for preventing the backscattered electrons taken in on the electron beam column side from returning to the surface to be drawn from the periphery other than a portion slightly larger than the deflection region of the electron beam. Since it is provided, the backscattered electrons generated from the surface to be drawn at the time of drawing and taken into the electron beam lens barrel side are reflected by hitting a member on the side of the electron beam lens barrel, and return to the surface to be drawn to draw the surface to be drawn. Most of the reflected electrons that have been reflected impinge on the reflected-electron shielding means when they are irradiated. Since the backscattered electron shielding means is non-magnetic and connected to the ground, the backscattered electrons colliding with the backscattered electron shielding means are absorbed by the backscattered electron shielding means and are prevented from returning to the drawing surface. As a result, deterioration of drawing accuracy is suppressed to a small level, and high drawing accuracy is obtained.

Further, according to the electron beam drawing apparatus of the second aspect, the reflection electron shielding means is provided on the tip end side of the electron beam lens barrel, and the deflection area of the electron beam emitted from the electron beam lens barrel. A non-magnetic shielding plate having a slightly larger electron beam transmitting hole and shielding the periphery of the electron beam transmitting hole, and means for connecting the non-magnetic shielding plate to the ground are provided. The generated backscattered electrons are taken into the electron beam lens barrel side through the electron beam transmission hole, and the backscattered electrons taken into the electron beam lens barrel side are transferred from the periphery other than the electron beam transmission hole to the drawing surface. Since it is configured so as not to return, the backscattered electron shielding means can be simply and inexpensively constructed, and the backscattered electrons generated from the drawing surface at the time of drawing are taken in from the hole of the non-magnetic plate, and the member on the electron beam barrel side To Reflected standing, tries to irradiate the object image plane returns to the drawing surface, the non-magnetic plate for around the hole is closed, most of the reflected backscattered electrons impinge on the non-magnetic plate. Since the non-magnetic plate is connected to the ground, the reflected electrons that collide with this are absorbed by the non-magnetic plate and are prevented from returning to the drawing surface. As a result, the deterioration of the drawing accuracy can be suppressed to a low level, and high drawing accuracy can be obtained.

According to the electron beam drawing apparatus of the third aspect, in addition to the effect of the second aspect, the backscattered electron shield means positions the non-magnetic shield plate in the optical axis direction of the electron beam lens barrel. Since the optical axis direction position adjusting means for adjustment is provided, it is possible to take in more reflected electrons with a smaller electron beam transmitting hole.

According to the electron beam drawing apparatus of claim 4, in addition to the effect of claim 2 or 3, the backscattered electron shield means causes the non-magnetic shield plate to be aligned with the optical axis of the electron beam lens barrel. Since the optical axis orthogonal direction position adjusting means for adjusting the position in the vertical plane is provided, there is an effect that a larger number of backscattered electrons can be taken in by a smaller electron beam transmitting hole.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an embodiment of the present invention.

FIG. 2 is a detailed enlarged view of a portion A of FIG.

[Explanation of symbols]

1 ... Device body 2 ... Drawing room 3 ... Electron beam lens barrel 5 ... Sample (material to be drawn) 5A ... Sample surface (drawing surface) 6 ... Electron beam 7 ... Non-magnetic shield plate (non-magnetic shield member) 7A ... Tip 16 ... Earth 17 ... Electron beam transmission hole 18 ... Backscattered electron detector 20 ... Ground connection means 22 ... Position adjusting means in the direction orthogonal to the optical axis 24 ... Optical axis direction position adjusting means 100 ... Reflection electron shielding means

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Claims (2)

(57) [Claims] 1. An electron beam drawing apparatus for drawing an electron beam emitted from an electron beam lens barrel by deflecting and irradiating the surface to be drawn with the electron beam, the electron beam drawing device being provided on a front end side of the electron beam lens barrel.
A little less than the deflection means of the electron beam emitted from the lens barrel
Has a large electron beam transmission hole in the
A non-magnetic shield plate that shields the periphery of the hole, a means for connecting the non-magnetic shield plate to the ground, and a non-magnetic shield plate in the optical axis direction of the electron beam barrel.
Position and an optical axis direction position adjusting means for adjusting a reflection electrons generated from the object image plane at the time of drawing, the electrostatic
Take it into the electron beam lens barrel through the secondary beam transmission hole.
The reflected electrons taken into the electron beam column side are the above-mentioned electrons.
Do not return to the drawing surface from the area other than the beam transmission hole
An electron beam drawing device characterized by being configured . 2. An optical axis orthogonal direction position adjusting means for adjusting the position of the non-magnetic shield plate in a plane perpendicular to the optical axis of the electron beam column is further provided. The electron beam drawing apparatus according to claim 1.