JPH07142318A - Method and apparatus for electron beam exposure - Google Patents

Abstract

PURPOSE:To perform electron beam exposure, wherein space electric charge effect is suppressed, by generating astigmatism at a front stage of a reducing lens, correcting the astigmatism of a slit image at a rear stage, and performing the exposure. CONSTITUTION:A quadrupole-field generating coil 27 is provided between a fourth lens 20 and a round aperture 21. Thus astigmatism is generated. The second slit image through a fifth lens 22 is also expanded with the astigmatism with the astigmatism generated by the quadrupole-field generating coil 27. However, the astigmatism is corrected by using the quadrupole-filed generating coil for correcting the astigmatism contained in a sixth lens 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention draws a pattern directly on a semiconductor wafer or mask based on pattern data.
With regard to the electron beam exposure technology of the direct writing method, electrons that are charged particles repel each other to cause out-of-focus, reduce the space charge effect, and maintain the uniformity of the current density, with a uniform beam current and no waste. It provides a technique for exposing.

Further, particularly for a slit (or a group of slits) having a large area such as a blanking aperture array (hereinafter referred to as BAA), the uniform irradiation range is not exceeded and the round aperture is not exceeded. It is intended to provide a technique capable of irradiating a beam on the entire surface of the BAA without deteriorating the effect of squeezing the beam.

[0003]

2. Description of the Related Art The following four methods have been put into practical use as electron beam exposure apparatuses. 1. A point beam method in which beams are used in the form of spots and a pattern is formed by the set. 2. A variable rectangular beam method that uses two kinds of rectangular slits and forms rectangular beams of different sizes by changing the combination, and forms a pattern with the set.

3. A stencil mask method that uses a stencil mask with the desired pattern shape and exchanges and burns each pattern. 4. BAA that uses a set of two-dimensional slits and turns on / off each slit to form an arbitrary pattern
method.

FIG. 7 shows a block diagram of an electron beam optical system which has been conventionally used. Note that some of the deflectors and the like are omitted in the drawing. An electron beam is generated by the LaB ₆ filament 71. The lenses include the first lens 74 to the sixth lens 84, and the first, second, and third lenses 74, 76, 7
7 is a focusing lens, 4th and 5th lenses 80 and 82 are reduction lens groups, and 6th lens 84 is a projection lens.

A first slit 75 is provided between the first lens 74 and the second lens 76, and a second slit 7 is provided inside the third lens 77.
8 and a blanking electrode 79 for turning on / off the beam is provided between the third lens 77 and the fourth lens 80. The second slit 78 differs depending on each method,
The variable rectangular beam method has a rectangular shape, the stencil mask method has a mask pattern shape, and the BAA method has a BAA slit.

Further, between the fourth lens 80 and the fifth lens 82, there is a round aperture 81 for narrowing the beam, which is used for increasing the resolution. The sixth lens 84 has an astigmatism correction coil 83 that generates a quadrupole field in order to correct astigmatism that occurs when the beam is deflected,
Dynamic correction is performed to change the correction amount according to the deflection position of the main deflector.

The operating principle and effect of the quadrupole field coil for astigmatism correction are described in, for example, the Electron / Ion Beam Handbook (2nd edition, Nikkan Kogyo Shimbun, September 1986).
(Published on 25th), pages 72 to 83. In the figure, the solid line shows the divergence and focus of the crossover image by the beam of the electron gun, and the dotted line shows the divergence and focus of the slit image.

The electron beam emitted from the electron gun composed of the LaB ₆ filament 71 is, as shown by the solid line, between the second and third lenses 76 and 77 and the blanking electrode 7.
9, the light is focused in the round aperture 81 and the sixth lens 84 to form a crossover image. The image of the first slit 75 is formed on the second slit 78 as shown by the dotted line, and the second slit image generated here (in the case of a variable rectangular beam, an image obtained by combining the first slit and the second slit) is formed. )
Is reduced by the fourth and fifth lenses 80 and 82, is narrowed down by the round aperture 81, and is a sixth projection lens.
The image is transferred onto the sample 85 on the sample table 86 by the lens 84.

[0010]

The electron beam exposure apparatus used conventionally has the following drawbacks. The first problem is that the space charge effect that causes beam blur cannot be reduced.
The space charge effect is proportional to the flight distance of the beam and the current value.
Therefore, it can be suppressed by reducing the flight distance of the beam (= focal length of the lens) or reducing the current value.

However, in order to reduce the focal length of the lens, it is necessary to increase the refractive index of the beam. Therefore, the magnetic field strength of the lens must be increased, and a large amount of current must be passed through the lens coil. As a result, the heat generated by the lens coil becomes large, and the heat causes the sample to expand, causing problems such as misalignment and pattern misalignment.

Further, even if the problem of heat generation can be cleared, the magnetic field strength cannot be increased beyond the saturation magnetic pole density of the material used for the magnetic poles of the lens coil.
There was a limit to increasing the magnetic field strength of the lens. On the other hand, in order to reduce the current value of the beam, it is necessary to lengthen the shot time to keep the total current value constant in order to secure a constant exposure amount, and there is no choice but to lower the throughput. there were.

Therefore, in the conventional method, an effective means for avoiding the space charge effect cannot be taken. The second problem is that the beam cannot be used efficiently because the area cut out by the slit is smaller than the effective area of the beam uniform irradiation portion.

FIG. 8 shows, for a uniform irradiation range of the beam,
It is a figure explaining the utilization efficiency of the beam by a slit.
If the uniform irradiation area of the beam is a circle with a diameter φ and a rectangular slit with a short side m and a long side am is cut out, the uniform irradiation area S ₁ of the beam and the slit area S ₂ are respectively S ₁ = π (φ / 2) ² = (π / 4) φ ² S ₂ = am · m.

From the Pythagorean theorem in the figure, φ ² = (am) ² + m ² = (a ² +1) m ² ∴S ₂ = am · m = am ² = aφ ² / (a ² +1) Therefore, the beam effective The utilization rate S ₂ / S ₁ is expressed by the following equation.

[0016]

[Equation 1] FIG. 9 is a graph showing the effective utilization rate of the beam, where the horizontal axis is the ratio a of the short side to the long side of the rectangular slit, and the vertical axis is the effective utilization rate S.
₂ / S ₁ . It can be seen that in the case of a = 1 square, the effective utilization rate becomes maximum at about 64%, and in the case of a> 1 or a <1 rectangle, it decreases.

If, for example, a rectangular slit having a long side to short side ratio of 3 (a = 3) is used as the second slit, the effective utilization rate is reduced to about 38%. The slits that are normally used are not necessarily square. Therefore,
After all, since the current density is low and the shot time is long, there is a problem that the throughput cannot be increased.

Thirdly, there is a problem that the beam range for irradiating the BAA cannot be enlarged especially as a problem of using the BAA method. In the BAA, the size of the second slit (= BAA) is huge compared to the variable rectangular beam method and the stencil mask method which have been used up to that point. However, the irradiation beam must be uniform over the entire surface of the slit.

When the size of the first slit is increased, the effect of narrowing the beam emitted from the electron gun is reduced, and a beam having a cross-sectional area wider than the uniform irradiation range is emitted, so that the uniformity of the beam is reduced. . On the contrary, when the size of the first slit is reduced, the beam emitted from the electron gun can be narrowed, and thus the uniformity can be improved, but the enlargement ratio for the second slit must be increased. I won't.

When the enlargement ratio of the slit image becomes large, the contraction ratio of the crossover image becomes large, so that the crossover image at the round aperture portion becomes small and the effect of narrowing the beam becomes small. Go down. At this time, if the aperture of the round aperture is made small in order to improve the uniformity of the beam, the current density is lowered and the throughput is lowered.

Therefore, there is no method for uniformly irradiating the BAA and uniformly exposing the sample. As described above, the conventional method cannot suppress the space charge effect. The shot time cannot be shortened because the effective utilization rate of the beam cannot be increased. BAA
It is not possible to irradiate a uniform beam on the entire surface of the type slit and evenly irradiate the sample. There was such a problem.

[0022]

SUMMARY OF THE INVENTION The present invention provides an electron beam exposure technique that solves the above problems. The problem is to generate astigmatism using an astigmatism generating unit provided in the front stage of the reduction lens, and the generated astigmatism using an astigmatism correction unit provided in the rear stage of the reduction lens. And a step of exposing the sample using a projection lens to solve the above problem.

Alternatively, the problem can be solved by an electron beam exposure method characterized in that astigmatism correction means provided in the projection lens is used as a coil for correcting the astigmatism. Alternatively, a step of generating astigmatism by using the astigmatism generating means provided at a position after the first slit and at which a crossover image is formed, and an astigmatism after the second slit. This is solved by an electron beam exposure method, which comprises a step of correcting the generated astigmatism using a point aberration correction means, and a step of exposing a sample with a projection lens.

Alternatively, a step of generating astigmatism by using an astigmatism generating means provided in front of the first slit,
A step of correcting the astigmatism by using the astigmatism correction means provided in the second stage of the second slit, in which the first slit image is converged in the latter stage of the first slit; And a step of exposing on a sample by using the electron beam exposure method.

Alternatively, it is solved by an electron beam exposure method characterized in that a blanking aperture array is used as the second slit. Alternatively, it is solved by an electron beam exposure apparatus characterized by comprising a reduction lens, an astigmatism generation unit provided before the reduction lens, and an astigmatism correction unit provided after the reduction lens. It

Alternatively, the first slit, the astigmatism generating means for generating astigmatism, which is provided at the position after the first slit and where the crossover image is formed, and the second slit. And an astigmatism correction unit that corrects the generated astigmatism provided after the second slit.

Alternatively, the first slit, the astigmatism generating means for generating astigmatism provided in the preceding stage of the first slit, and the first slit image converged in the latter stage than the first slit. The electron beam exposure apparatus is provided with a second slit and an astigmatism correction unit that is provided at a subsequent stage of the second slit and corrects the astigmatism.

[0028]

By astigmatism occurring before the reduction lens, the concentration of the beam can be prevented and the space charge effect can be prevented. By correcting the generated astigmatism in the subsequent stage of the reduction lens, it is possible to print a pattern having no aberration. In addition, the astigmatism is generated at the position before the first slit and at the position where the crossover image at the latter stage is formed, so that the beam is uniformly irradiated on the entire surface of the large second slit such as the BAA type. You can By correcting the generated astigmatism at the subsequent stage of the second slit, it is possible to print a pattern having no aberration.

The effects of the present invention will be described below. FIG. 1 is a diagram for explaining the principle of the present invention. 1 is a slit image, 2 is an astigmatism generating means, 3 is a crossover image when no astigmatism is generated, and 4 is astigmatism. At this time, a crossover image, 5 is a reduction lens, and 6 is a reduced slit image.

The distance between the slit image 1 and the reduction lens 5 is 10
0 mm, and the crossover images 3 and 4 are reduction lenses 5.
Is imaged on the surface 20 mm in front of. If there is no astigmatism generating means 2, the crossover image 3 has a radius QS = 25.
It is a circle of 0 μm. If the focal length of the reduction lens 5 is 20 mm, the geometrical optics formula 1 / f = 1 / s + 1 / s ′ (f: focal length, s: distance between lens and object surface, s ′: distance between lens and image surface) ), The image can be located 25 mm from the reduction lens.

Therefore, the slit image 1 of 50 μm square is
With the reduction lens 5, s' / s, that is, 25/100 =
It is reduced to 1/4 and an image 6 of 12.5 μm □ is formed. According to the present invention, the astigmatism generating means is used, for example, 1: 3.
It is assumed that the crossover image 3 is stretched. The stretched crossover image 4 has an elliptic shape with a long radius QR = 750 μm and a short radius 250 μm.

If the slit image 1 is adjusted by the astigmatism generating means so as to be emitted from the reduction lens 5 from the position P of 75 mm, PQ: PQ '= QR: due to the similarity of ΔPQR and ΔPQ'R'. Q'R '∴55: 75 = 750: Q'R'∴Q'R'= 1023 μm Therefore, the slit image 1 stretched to 750 μm on the surface of the crossover image 4 is 1023
.mu.m.

Here, the focal length of the reduction lens 5 is 20 mm.
Therefore, when the position of the image plane of the slit image 1 in the stretched direction (the direction in which astigmatism is generated) is obtained using the geometrical optics formula, the image is 27.3 m from the reduction lens 5.
m, 2.3 mm from the image 6 position. △ P '
From the similarity of Q'R 'and △ P'Q''R''P'Q':P'Q'' = Q'R ': Q''R''∴27.3: 2.3 = 1023: Q''R ″ ∴Q ″ R ″ = 86.2 μm Therefore, at the position of the reduced image 6, the size of the blurred image including astigmatism is approximately 86.2 × 2 = 172.
It will be a rectangle with a width of 4 μm and a width of 12.5 μm.

From this fact, the slit image area when the astigmatism generating means is not used is 12.5 × 12.5 μm ² = 156 μm.
^On the other hand, when the astigmatism generating means is used, the slit image area is 172.4 × 12.5 μm ² = 2155 μm ^{2 while the} value is ² . Since the space charge effect is proportional to the square of the current density,
It is inversely proportional to the square of the area. Thus, the space charge effect, according to the present invention and ^{156 2/2155 2 = 5.24 ×} 10 -3, about 0.5
It is possible to reduce the percentage.

By correcting the astigmatism generated here by using an astigmatism correcting means such as a quadrupole field coil in the subsequent stage, it is possible to perform exposure with the space charge effect suppressed.
Next, the effect on the effective usage rate of the beam uniform irradiation portion will be described. FIG. 2 is a diagram for explaining the effect of the effective beam utilization rate of the slit on the uniform irradiation range of the beam according to the present invention.

A uniform irradiation range of a beam laterally extended by astigmatism is an ellipse having a major axis bφ and a minor axis φ. However, for simplicity, it is not an ellipse but is considered to be a combination of a semicircle having a diameter of φ combined with a rectangle having a long side (b-1) φ and a short side φ. When a rectangle with a short side m and a long side am is cut out with a slit, the beam uniform irradiation range area S ₁ and the slit area S ₂ are respectively S ₁ = π (φ / 2) ² + (b-1) φ ² = (π / 4 + b-1) φ ² S ₂ = am · m From the Pythagorean theorem, (φ / 2) ² = (m / 2) ² + [{am- (b-1) φ} / 2] ² ∴φ ² = m ² + {am- (b-1) φ} ² = (a ² +1) m ² -2a (b-1) φm + (b-1) ² φ ² ∴ (a ² +1) m ² −2a (b−1) φm + (b ² −2b) φ ² = 0 From the root formula of the quadratic equation, the value of m for which m> 0 is obtained.

[0037]

[Equation 2] Substituting for S ₂ ,

[0038]

[Equation 3] Therefore, the utilization efficiency S ₂ / S ₁ is

[0039]

[Equation 4] FIG. 3 is a graph showing the beam utilization efficiency of the present invention,
The horizontal axis represents the aspect ratio a of the slit, and the vertical axis represents the beam utilization efficiency S.
₂ / S ₁ and the length-b ratio b of the crossover image is used as a parameter. The beam utilization efficiency can be improved by appropriately selecting the shape of the crossover image (value of b) according to the shape of the slit (value of a).

When the slit is a square with a = 1, the crossover image has a circular shape with b = 1 and the utilization efficiency is maximized. This is in agreement with the method used conventionally, but is still about 64%. Like BAA, for example, a =
In the case of the rectangular slit of 3, the beam utilization efficiency can be increased to about 79% by selecting 3: 1 (b = 3) as the crossover image.

Therefore, since the current density can be increased, the shot time can be shortened and the throughput can be increased. Further, by selecting the shape of the crossover image in accordance with the shape of the slit, it is possible to keep the enlargement ratio for the second slit low while keeping the size of the first slit small, and to reduce the reduction ratio of the crossover image. Can be lowered.

Therefore, since beam shaping can be performed by both the first slit and the round aperture, uniform irradiation can be performed on the sample. Further, since it is not necessary to reduce the aperture of the round aperture, it is not necessary to lower the current density, the shot time can be shortened, and the throughput can be increased.

[0043]

FIG. 4 is a schematic diagram for explaining the structure of an electron beam exposure apparatus for explaining the first embodiment of the present invention.
It should be noted that parts such as a deflector that are not directly related to the present invention are omitted in the drawing. An electron beam is generated from the LaB ₆ filament 11. There are lenses from the first lens to the sixth lens, the first, second and third lenses 14, 16 and 17 are focusing lenses, the fourth and fifth lenses 20 and 22 are reduction lens groups,
The sixth lens 24 is a projection lens.

The sample 25 is set on the sample table 26.
500 μm □ between the first lens 14 and the second lens 16
There is a first slit 15 in which the unwanted part of the beam is removed. A BAA 18 is provided as a second slit in the third lens 17, and 1024 slits in 128 rows and 8 columns are gathered.

A blanking electrode 1 for turning on / off the beam is provided between the third lens 17 and the fourth lens 20.
9 and a round aperture 21 for beam shaping between the fourth lens 20 and the fifth lens 22. The sixth lens 24 has an astigmatism correction coil 23 that generates a quadrupole field in order to correct the astigmatism that occurs when the beam is deflected, and the correction amount is adjusted according to the deflection position of the main deflector. Dynamic correction that changes is performed.

In the figure, the solid line shows the divergence and focusing of the beam by the electron gun, and the dotted line shows the divergence and focusing of the slit image. The electron beam emitted from the electron gun composed of the LaB ₆ filament 11 has a second,
Between the third lens 16 and 17, and the blanking electrode 19,
The light is focused in the round aperture 21 and the sixth lens 24 to form a crossover image.

The image of the first slit 15 is formed on the second slit 18 as shown by the dotted line, and the BAA generated here is generated.
The second slit image by 18 is the round aperture 21.
And the front of the sixth lens 24 and the sample surface are focused and imaged. The first slit image with a size of 500 μm is magnified 6 times by the front part of the second lens 14 and the third lens 16 to form a beam irradiation range of 3 mm □ on the BAA 18 surface in the third lens 17. To do.

The size of the BAA 18 is 3 × 1 mm ² ,
Since the 1024 slits can be turned on / off individually, a maximum of 1024 points can represent an arbitrary two-dimensional figure. The second slit image created by the BAA 18 is reduced by the fourth and fifth reduction lenses 20 and 22,
The sixth lens 2 is shaped by the round aperture 21.
4 is transferred to the sample 25.

In this embodiment, a quadrupole field generating coil 27 is installed between the fourth lens 20 and the round aperture 21 to generate astigmatism. Because of this,
Even at the position where the slit image is focused between the lens 22 and the sixth lens 24 and where the electric field effect is most likely to occur, the current density can be reduced by the astigmatism, so that the space charge effect is reduced as compared with the conventional example. be able to.

Due to the astigmatism generated by the quadrupole field generating coil 27, the second slit image passing through the fifth lens 22 also spreads with astigmatism. However, the sixth lens 2
Aberration can be corrected by using a quadrupole field generating coil for correction of astigmatism which is included in the reference numeral 4. Of course, the aberration correction may be performed by separately providing a quadrupole field generating coil between the fifth lens 22 and the sixth lens 24.

FIG. 5 is a schematic diagram for explaining the structure of an electron beam exposure apparatus for explaining the second embodiment of the present invention. The same numbers and symbols as in FIG. 4 indicate the same or corresponding portions. In the present embodiment, a quadrupole field generating coil 28 that generates astigmatism is installed between the second lens 16 and the third lens 17, and a quadrupole field generation for correcting astigmatism is provided in the subsequent stage of the third lens 17. The coil 29 is installed.

The first slit image having a size of 250 μm is
It is magnified 4 times by the front part of the second lens 14 and the third lens 16, and is 3 times by the astigmatism generation coil 28.
By being doubled, B in the third lens 17 is increased.
A beam irradiation area of the same size as the BAA 18 of 3 × 1 mm ² is formed on the AA 18 surface. The second slit image by BAA has its aberration corrected by the astigmatism correction coil 29, and the sample 25 by the reduction lenses 20, 21 and the projection lens 24.
Exposed.

In this embodiment, the first embodiment is different from the first embodiment.
Since the size of the slit is small and the expansion rate of the second slit is also small, beam shaping can be performed by both the first slit and the round aperture, and the sample 25 can be uniformly irradiated. FIG. 6 shows the third aspect of the present invention.
FIG. 3 is a schematic diagram illustrating the structure of an electron beam exposure apparatus for explaining the example of FIG. The same numbers and symbols as in FIG. 4 indicate the same or corresponding portions.

In this embodiment, a quadrupole field generating coil 28 for generating astigmatism is installed in front of the first lens 14, and a quadrupole field generating coil 29 for correcting astigmatism is provided at the subsequent stage of the third lens 17.
Has been installed. The beam generated by the electron gun is applied to the first slit by the astigmatism generation coil 30 in a state where the beam is expanded three times. The first slit is 750 x 250
It has a size of μm ² , and the first slit image is the second
It is magnified 4 times by the front part of the lens 14 and the third lens 16 and 3 × 1 mm on the BAA 18 surface in the third lens 17.
A beam irradiation area having the same size as the BAA 18 of ² is formed.

The second slit image by BAA has its aberration corrected by the astigmatism correction coil 29, and the reduction lens 2
The sample 25 is exposed with 0, 21 and the projection lens 24. In this embodiment, the size of the first slit is larger than that of the second embodiment, but the effect of the slit does not change because the beam is stretched three times. Further, since the expansion ratio of the second slit can be reduced as in the second embodiment, the beam shaping can be performed by both the first slit and the round aperture, and the sample 25 can be uniformly irradiated.

In the second and third embodiments, the astigmatism generating coils are placed only before and after the second slit, but as shown in the first embodiment, they are also placed before and after the reduction lens, so that It goes without saying that the effect of avoiding the space charge effect can also be obtained. Further, in the first to third embodiments, the case of BAA as the second slit is shown, but it goes without saying that the same result can be obtained by the variable rectangular beam method or the stencil mask method.

[0057]

According to the present invention, the astigmatism generating means is arranged in the front stage of the reduction lens and the astigmatism correction means is arranged in the rear stage, and astigmatism is generated in the front stage of the reduction lens, and the astigmatism of the slit image is reduced in the rear stage. By performing exposure by correcting the point aberration, electron beam exposure with suppressed space charge effect can be performed.

Even if the astigmatism correction coil in the projection lens is used as the astigmatism correction means, electron beam exposure with the space charge effect suppressed can be performed in the same manner. Further, the astigmatism generation means is arranged in the front stage of the first slit, the astigmatism correction means is arranged in the rear stage of the second slit, and astigmatism is generated in the front stage of the first slit, so that the entire surface of the second slit is covered. It is possible to irradiate the beam uniformly, and by correcting the astigmatism in the subsequent stage of the second slit, the beam can be shaped by the first slit and the round aperture, and uniform electron beam exposure can be performed.

Further, astigmatism generating means is arranged at the position where the crossover image is formed in the latter stage of the first slit, and astigmatism correction means is arranged in the latter stage of the second slit, and astigmatism is corrected in the latter stage of the first slit. By generating point aberration, it is possible to irradiate the beam uniformly over the entire surface of the second slit, and by correcting astigmatism in the subsequent stage of the second slit, the beam can be shaped by the first slit and the round aperture. Therefore, uniform electron beam exposure can be performed.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram illustrating the effect of beam utilization efficiency according to the present invention.

FIG. 3 is a graph showing the effect of beam utilization efficiency according to the present invention.

FIG. 4 is a schematic diagram of an electron beam exposure apparatus showing a first embodiment of the present invention.

FIG. 5 is a schematic view of an electron beam exposure apparatus showing a second embodiment of the present invention.

FIG. 6 is a schematic diagram of an electron beam exposure apparatus showing a third embodiment of the present invention.

FIG. 7 is a configuration diagram of an electron beam exposure apparatus showing a conventional example.

FIG. 8 is a diagram illustrating beam utilization efficiency according to a conventional example.

FIG. 9 is a graph showing beam utilization efficiency according to a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Slit image 2 Astigmatism generating means 3 Crossover image when there is no astigmatism 4 Crossover image when there is astigmatism 5 Reduction lens 6 Reduced projection image of slit image 11,71 Filament 12,72 Wehnelt 13 , 73 Anode 14,74 First lens 15,75 First slit 16,76 Second lens 17,77 Third lens 18,78 Second slit 19,79 Blanking electrode 10,80 Fourth lens 21,81 Round aperture 22,82 Fifth lens 23,83 Quadrupole field coil for correcting astigmatism in projection lens 24,84 Sixth lens (projection lens) 25,85 Sample 26,86 Sample stage 27,28,30 For astigmatism generation Quadrupole field coil 29,31 Quadrupole field coil for astigmatism correction

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroshi Yasuda 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (8)

[Claims] 1. A step of generating astigmatism using an astigmatism generating means (27) provided in a stage before the reduction lens (22), and an astigmatism correction provided in a stage after the reduction lens (22). An electron beam exposure method comprising: a step of correcting the generated astigmatism using a means; and a step of exposing the sample (25) using a projection lens (24). 2. The electron beam exposure method according to claim 1, wherein astigmatism correction means (23) provided in the projection lens is used as means for correcting the astigmatism. 3. A step of generating astigmatism using an astigmatism generating means (28), which is provided after the first slit (15) and at a position where a crossover image is formed, , Astigmatism correction means (29) provided after the second slit (18)
And a step of exposing the sample using a projection lens (24), and a step of exposing the sample using the projection lens (24). 4. A step of generating astigmatism using an astigmatism generating means (30) provided in a front stage of the first slit (15), and a step after the first slit (15) in a rear stage. A step of correcting the astigmatism by using the astigmatism correction means (31) provided in the latter stage of the second slit (18) for converging the first slit image, and using the projection lens (24) And a step of exposing on a sample (25). 5. The electron beam exposure method according to claim 3, wherein a blanking aperture array is used as the second slit (18). 6. A reduction lens (22), an astigmatism generation means (27) provided before the reduction lens, and an astigmatism correction means provided after the reduction lens. And electron beam exposure equipment. 7. Astigmatism generation for generating astigmatism provided at a position after the first slit (15) and the first slit (15) and where a crossover image is formed. Means (28)
And an astigmatism correction means (29) for correcting the generated astigmatism, which is provided after the second slit (18). Exposure equipment. 8. A first slit (15), an astigmatism generating means (30) for generating astigmatism provided before the first slit (15), and a second slit (18). And an astigmatism correction means (31) for correcting the astigmatism provided at the rear stage of the second slit (18) where the first slit image is focused at the rear stage of the first slit (15). ) And an electron beam exposure apparatus.