JPH021111A - Electron beam exposure device and electron beam exposure method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Table of Contents] Overview Cattle ζ Industrial Application Field i Conventional Technology
Problems to be solved by the present invention Means for solving the problem
1+moxibustion effect
17-sided example t
ri(a) Description of electron beam exposure apparatus based on the present invention
(Fig. 1) (b) Eddy current generation mechanism in the moving stage (Figs. 7 and 8) (C) Explanation of the magnetic objective lens based on the present invention (Figs. 3 to 8)
Figure 6) Effects of the present invention 29 [Summary] The present invention provides a magnetic objective lens for an electron beam exposure device that projects an electron beam onto an object mounted on a stage that is continuously moving in a predetermined direction. Regarding improvements.

The purpose is to prevent unnecessary magnetic flux from the magnetic objective lens from leaking toward the stage in order to improve the convergence of the electron beam.

The magnetic objective lens includes a magnetic objective lens having a lower pole piece provided opposite to the object.

A bore is opened in the lower pole piece corresponding to a predetermined scanning space of the electron beam scanned in a direction perpendicular to the main movement direction of the object, and the electron beam passes through the bore. Most of the magnetic flux within the magnetic objective lens is blocked by a portion other than the bore of the lower pole piece, and is prohibited from leaking to the stage, and with this configuration, the leakage magnetic flux is prevented from leaking to the stage. This has the effect of maintaining good convergence of the electron beam by avoiding the generation of eddy currents within the stage caused by eddy currents.

[Industrial application field]

The present invention relates to an electron exposure apparatus used in electron beam lithography, and more specifically, the present invention relates to an electron exposure apparatus used in electron beam lithography, and more particularly, to an electron exposure apparatus that avoids the generation of eddy currents due to leakage magnetic flux generated in a stage that carries a workpiece and moves continuously. The present invention relates to a magnetic objective lens that can maintain good convergence of the electron beam.

The electron beam exposure system is a large-scale semiconductor device.

That is, it is widely known as a method for forming fine circuit patterns for LSI. As the integration density of LSIs increases, conventional optical lithography techniques have reached their limits, and more precise techniques such as electron beam lithography have been required. The main feature of electron beam lithography is its high resolution. The light diffraction problems inherent in optical lithography are overcome with 10 to 20 Kv electron beams. This is because the equivalent wavelength of the electron beam is less than 1 Å, which is much shorter than the wavelength of ultraviolet light. Furthermore, since the pattern formation is entirely controlled by an electronic computer and the process flow is short, it is easy to mechanize the related LSI manufacturing process, and it is suitable for mass production in terms of yield and production stability.

Electron beam lithography is classified into two types: electron beam projection type and electron beam scanning type, and the present invention relates to the latter type. In electron beam scanning lithography, one circuit pattern is drawn by controlling the deflection and ON/OFF of a finely focused electron beam by an electronic computer.

The electron beam scanning mechanism is an electron beam forming means that forms electrons from an electron source into an electron beam with a round or narrow cross section.

An electron beam deflection means for deflecting an electron beam and scanning the electron beam by a rask or vector scanning method, and controlling the movement of a stage on which a workpiece is placed by controlling the electron beam deflection means so as to scan the electron beam on the workpiece. It is comprised of a pattern generation control means for drawing a required circuit pattern. From now on, the workpiece will be described as a semiconductor wafer.

Generally, the scanning span is 2mm to avoid lens aberrations.
It is limited to Therefore, the entire surface of the wafer is divided into a large number of divided areas, and the divided areas are sequentially exposed. Of course wafer.

In some cases, the stage is moved in synchronization with the scanning of the electron beam. The stage is typically movable in the X-Y direction in a horizontal plane. There are two types of movement.

One is the step-and-repeat method, and in the nine-step method, an element pattern is drawn by irradiating an electron beam within a rectangular segmented area on the wafer. When pattern formation in one sectioned area is completed, the wafer is moved and pattern formation on the next sectioned area is started.

Another method is a continuous moving stage method,9 for example:
Be1l EBES (el
ectron beam exposure system
em), and the present invention also relates to this method.

In this method, the electron beam is scanned using the Rusk method.

The stage is continuously moving in a direction normal to the scanning direction. The advantage of this method is that the movement of the stage and the scanning of the electron beam are performed simultaneously in parallel, saving 9 hours. On the other hand, in the step-and-repeat method, mechanical vibrations occur on the stage when the stage stops, and it is necessary to wait for the mechanical vibrations to converge before the secondary stage electron beam scanning starts. It takes longer. In the inventor's experience, this waiting time reaches 0.3 seconds. Assuming that a 4-inch wafer is subjected to electron beam exposure in 2 mm sectional areas, the total waiting time is 520 seconds per wafer, which occupies about 70x of the electron beam exposure time for the entire wafer. Therefore, L.S.
It seems that the continuous moving stage method is more suitable for mass production of I.

[Conventional technology]

However, the 9-zero continuous moving stage system also has drawbacks. That is, when a portion of the magnetic flux generated within the magnetic objective lens, that is, leakage magnetic flux, crosses the moving stage, an eddy current is generated, and as a result, the eddy current generates new magnetic flux, which is projected onto the wafer. The convergence of the electron beam is disturbed and the resolution of the nine-circuit pattern formation is reduced. This matter will be discussed in detail later, but one related point is that the magnetic objective lens of the magnetic lens system of a conventional electron beam exposure apparatus generally has a circular bore in the pole piece, which is one of its components. It is necessary to pay attention. The reason why the shape of the bore is circular is the result of following the design concept that all magnetic lens systems are designed to be rotationally symmetrical around the axis in order to suppress lens aberrations.

As a result of the circular bore being larger than the scanning space of the electron beam, there is no hindrance to the passage of the electron beam, but the strong magnetic flux generated within the magnetic objective lens passes through the bore. and project it onto the moving stage, disturbing the convergence of the associated electron beam, as will be discussed below.

Furthermore, in order to reduce lens aberrations of the magnetic lens system, especially the magnetic objective lens, it is desirable to control the electron beam so that it always runs on the axis of the magnetic objective lens. Also,
When the electron beam is projected onto the wafer, it is desirable that the electron beam be projected at right angles to the surface of the wafer. This is because if the electron beam is projected perpendicularly to the wafer surface, deformation of the drawn circuit pattern can be avoided even if the wafer surface has some unevenness or tomographic steps.

In order to achieve the above two objectives, a technique for translating the optical axis of a magnetic objective lens in the radial direction in response to the deflection of the associated electron beam has been developed.
VAL) has already been developed by International Business Machines Corporation (IBM) and is used in the company's EL3 system. The technology was introduced on March 1983.
It is disclosed in US Pat. No. 4,376,249, published under the designation 0B.

V A L [Two sets of deflection coils and two sets of compensation deflection coils (or optical axis shift coils) are provided inside the objective lens, and these coils are electrically connected in series. activated and activated at the same time. The optical axis of the magnetic objective lens is shifted parallel to the original optical axis by the compensation coil, and is shifted in the direction perpendicular to the wafer surface by two sets of deflection coils.
That is, the electron beam, which is doubly deflected parallel to the optical axis of the magnetic objective lens, is controlled so that it always aligns with the optical axis of the shifted magnetic objective lens. Since the electron beam is always on the optical axis of the magnetic objective lens, comatic aberration and chromatic aberration are effectively eliminated.

On the other hand, the wafer is mounted on a stage movable in the X-Y directions. When the stage includes a metal layer, eddy currents are generated in the stage when the leakage magnetic flux emitted from the compensation coil at the bottom of the magnetic objective passes through the wafer and reaches the stage. As mentioned above, since the pole piece at the bottom of the magnetic objective lens has a circular bore, it is unavoidable that this leakage magnetic flux enters the stage, and once the stage moves, eddy currents are inevitably generated within the stage. This impairs the electron beam focusing effect of the magnetic objective lens.

In order to exclude the above-mentioned bottom compensation coil and to block the influence of external magnetic flux, including the above-mentioned eddy currents.

V A I L (Variable a) from 18M company
xis immersion lens) was developed,
US Patent No. 1985.10.01.

No. 4,544,846. The VAIL is provided with a ferrite-like boreless lower pole piece, and the wafer to be processed is positioned above the lower pole piece and encased within a magnetic objective lens. The wafer is immersed in the magnetic flux of the magnetic objective lens, and the pole pieces of the magnetic objective lens act as a magnetic cage to confine the magnetic flux. Since the lower pole piece is made of ferrite, which is a ferromagnetic material, the magnetic flux within the magnetic objective lens enters the pole piece perpendicularly. As a result, the electron beam that has entered the magnetic objective lens is also projected perpendicularly to the pole piece, that is, perpendicularly to the wafer, making it possible to reduce pattern distortion. However, even with the VAIL structure, if an attempt is made to move the wafer continuously, eddy currents will suddenly occur in the lower pole piece, causing the above-mentioned problem. Can not.

Furthermore, regarding the above-mentioned VAL and VAIL, H, C
, MICROCIRCUI by Pfeiffer
T ENGINEERING, l5BN, 0123
457505. Reported on pages 72-81.

[Problem to be solved by the invention]

An object of the present invention is to improve the drawbacks of the magnetic objective lens of the conventional electron beam exposure apparatus described in detail above. In other words, because the bore of the lower pole piece of the conventional magnetic objective lens is formed into a circular shape symmetrical to the rotation axis, the magnetic flux generated inside the magnetic objective lens leaks to the outside from the circular bore and prevents the wafer from being mounted. This is an improvement of a magnetic objective lens that intersects a stage that has been moved and prevents eddy currents from being generated within the stage when the stage moves, thereby preventing the generation of new harmful magnetic flux that impairs the convergence of the electron beam. .

[Means to solve the problem]

Electron beam exposure that scans an electron beam in a scanning space that extends mainly in one direction, projects the electron beam onto an object that is continuously moving in a direction perpendicular to the scanning space, and draws a circuit pattern on the object. The apparatus includes a stage on which the object is mounted on one surface and is movable continuously in at least the movement direction, an electron emitting means, and a magnetic objective lens, and converges the electrons and forms them into an electron beam. It is configured to include an electron focusing means and a magnetic lens system having an electron beam A deflecting means for deflecting the electron beam. Among these elements, the magnetic objective lens further includes a coil for generating magnetic flux.

It consists of an upper pole piece made of a magnetic material and a lower pole piece made of a magnetic material and placed opposite to the object, and the pole piece O is a portion corresponding to the predetermined scanning space of the electron beam. The magnetic objective lens is characterized in that it has a bore provided to allow the electron beam to pass therethrough and to prohibit the passage of the magnetic flux generated within the magnetic objective lens.

[For production]

In the magnetic objective lens of the electron beam exposure apparatus according to the present invention, the bore provided in the lower pole piece facing the object such as a semiconductor wafer that is projected by the electron beam corresponds to the scanning space of the electron beam. It is provided. Due to this structure.

The electron beam can scan the surface of the object under the control of the central computer, and leakage magnetic flux from the magnetic objective lens is reduced as much as possible by the lower pole piece itself. As a result, the leakage magnetic flux that intersects the stage on which the object is mounted and is moving is attenuated, the eddy currents generated thereby are reduced, and the effect of disturbing the convergence of the electron beam is significantly suppressed.

〔Example〕

(a) Description of the electron beam exposure apparatus according to the present invention The electron beam exposure apparatus according to the present invention, except for its magnetic objective lens, consists of the following: 2. The inventor of the present invention has made an expenditure of 2000 yen on the electronic exposure system and method of operating the same. .

Published on 19B2.12.07. US patent no.
, 4.362, 942. In the present invention, the magnetic objective lens is improved. Although this apparatus can be used in a step, and, repeat method or in a continuous stage movement method, the present invention is limited to the latter method.

FIG. 1 shows an electron beam exposure apparatus according to an embodiment of the present invention. Electrons emitted from the electron gun G are converged by three converging lenses 4 and a magnetic objective lens 9 to form an electron beam B. The electron beam B passes through a magnetic objective lens 9 and is projected onto a desired position of a semiconductor wafer IO mounted on a stage 11 movable in the X-Y directions. The stage 11° and therefore the wafer 10 are continuously moving in the X direction. Of course, it is assumed that the X, Y, and X directions are orthogonal to each other.

Under the control of the pattern signal of central electronic computing 1cPU12,
The electron beam B is turned on and off by a beam blanking means (not shown), cut by a rectangular aperture 1, deflected by a deflection plate 2, and further cut by another rectangular aperture 3 to be shaped into a rectangular electron beam. .

The rectangular electron beam B shaped as described above in accordance with the pattern signal is passed through two deflection coil pairs 8a.

8b and a compensation coil (axis shift coil) 8c, on the surface of the wafer 10.

For example, it is projected perpendicularly to the center point of the first segmented area that is a target of 100 microns square. Thereafter, the electron beam B is deflected by the sub-deflection plate 5 to form a pattern consisting of a combination of several types of rectangular patterns. The sub deflection plate 5 is electrostatically controlled. Numbers 6 and 7 indicate a stigmator coil and a focusing coil, respectively.

After the pattern formation of the first divided area is completed, the electron beam B is moved and projected to the center point of the adjacent second divided area, and subsequently the pattern formation of this area is performed in the same manner under the control of the central computer CPU12. . In this way 9
For example, pattern formation for each of the 20 divided areas arranged in the Y direction is completed. i.e. width 100 microns, length 2mm
The pattern formation of the ribbon-shaped area is completed. Therefore,
It can be said that the Y direction is the main scanning direction. Hereinafter, when referring to the scanning direction, it refers to the above-mentioned main scanning direction.

Thereafter, the electron beam B is returned to a new divided area adjacent to the first divided area in the X direction. In this way, the entire striped area on the wafer 10 having a width of 2 mm, for example, extending in the X direction is projected onto the electron beam B. The electron beam projection is then moved to an adjacent 2 mm wide striped area and the above steps are repeated.

In the above example, the scanning of electron beam B is:

It is limited to a span of 2 mm in the Y direction and another narrow span of 100 microns in the X direction. The scan span mentioned above is significantly longer in the Y direction.

Since it is short in the X direction, the scanning space of the electron beam B is in a long and narrow region extending in the Y direction. The cross section of the scanning space perpendicular to the projection direction of the electron beam B has the shape of an elongated rectangle extending in the Y direction with a width of 2 mm and 100 microns in the example described above.

The stage 11 has an extremely sturdy and precise mechanism, and is movable in both the X and Y directions by a motor (not shown).

The wafer 10 mounted on the stage 11 can be moved accurately and stably according to the pattern signal. On the other hand, stage 1
Since the wafer 2 is continuously moving in the X direction, the movement of the wafer 10 mounted thereon is a combination of movement caused by the pattern signal and continuous movement. The actual spatial coordinate position of the wafer 10 on the stage 11 is detected by a laser interferometer 17, and is constantly detected by a central computer CP.
It is fed back to the UI 2, and the projection position of the electron beam B is continuously corrected to correspond to the pattern signal at that moment. Other components 2 e.g.

Coil 6.7. Memory 13, 16. Register 14° Adder 15. Converter 18. Subscriber 19,
Amplifier 21.24 is the subject of US patent no.

4.362942, so it will be omitted here.

(b) Mechanism of generation of eddy currents in a moving stage Before proceeding further, let us discuss in detail the mechanism of generation of eddy currents generated in the stage by magnetic flux crossing the aforementioned moving stage and its deleterious effects.

FIG. 7 is a sectional view of a main part showing the structure of a magnetic objective lens of a conventional electron beam exposure apparatus. The magnetic objective lens is configured in an axial seal around an axis A extending in the X direction, and includes an upper pole piece 101 a, a lower pole piece 10 l b facing the upper pole piece with a space 101 c in between, and a pole piece. A coil 102 that surrounds 101a and 101b and generates magnetic flux. A shield 105 surrounding the coil 102 and preventing magnetic flux from leaking out of the magnetic objective lens. Stage I07. which is movable in the X-Y direction. and a coil 104 that deflects the electron beam B in the Y direction. stage 10
7 has a complicated mechanism for driving the stage 107, but it is represented by a simple plate for simplicity.

The magnetic flux generated by the coil 102 is transferred to the pole piece 102a.
, 102b and radiates into the magnetic objective lens, forming a magnetic lens near the space 102c. The magnetic flux leaking outside the magnetic objective lens is blocked by the magnetic shield 105, and the magnetic flux radiated inside is blocked by the pole pieces 102a, 10.
It terminates on the inner wall of 2b. Thus, in principle, the magnetic flux should be confined within the magnetic objective lens, but each of the pole pieces 102a, 102b has circular bores 103a, 103b through which the electron beam B passes. As a result, the magnetic flux leaks downward through the bore 103b and the stage 1
Intersects with 07.

Although the stage 107 is made of an electrical insulator such as ceramic, its surface is covered with a deposited metal layer to prevent charge from accumulating. As a result, eddy currents are generated in the metal layer when the stage 107 moves due to the crossing magnetic fluxes. Furthermore, since the drive mechanism provided at the bottom of the stage 107 is usually made of metal,
When the mechanism moves, eddy currents are also generated here, and these eddy currents newly generate harmful magnetic flux that prevents the electron beam B from converging.

FIG. 8 is a partially cutaway perspective view of the conventional magnetic objective lens shown in FIG. 7, showing the stage 107. Pole piece 101a,
Only 101b is shown and the wafer is not shown.

When not scanning, the electron beam B is projected onto the median point PO, and when the scanning operation begins, it scans by reciprocating between both points PI and P2. As shown in FIG. 8, leakage magnetic flux 111 (indicated by a dotted line) leaks from the circular bore 103b to the stage 107.
intersect with As mentioned earlier, the circular shape of the bore 103b allows the electron beam B (shown by the solid line) to pass through the X-
This format was adopted with the intention of scanning in the Y direction and designing the magnetic objective lens to be rotationally symmetrical about axis A to eliminate lens aberrations. stage 107
a portion 106a in which the magnetic flux crossing the stage 107 increases when the stage 107 moves in the X direction as shown by an arrow 107a;
A decreasing portion 106b occurs. Such partial changes in magnetic flux density result in eddy currents 112 rotating in opposite directions.
a and 112b respectively as part 106a.

106, b. As a result, a new magnetic flux 110 that reaches the part 106b from the first part 106a is transferred to the electron beam B.
It occurs while intersecting with the path of

Due to this new magnetic flux 110, the electron beam B is deflected in the X direction. Strictly speaking, the electron beam B is deflected not only in the X direction but also in the X direction, albeit by a small amount. These deflections of the electron beam B by the magnetic flux 110 are outside the control of the central electron beam exposure unit CPU and in any case may disturb the convergence of the electron beam B and distort the circuit pattern drawn on the wafer (not shown). bring. The present invention aims to reduce the eddy current generated within the stage 107 described above.

(C) Description of the magnetic objective lens based on the present invention FIG. 2 is a cross-sectional view of the main part of the magnetic objective lens based on the present invention, and
The figure is a plan view of the lower pole piece of the magnetic objective lens shown in FIG. 2. Like the conventional example shown in FIG. 2, the magnetic objective lens shown in FIG. 4 has a rotationally symmetrical structure about axis A.

The magnetic objective lens according to the invention has an upper pole piece 3
1a, a lower pole piece 31b, a coil 90, and an outer shield 50. Furthermore, the electron beam B is
Deflection coil pair 34a for double (double) deflection in the direction
, 34b, and a compensation coil 34c for moving the lens axis of the magnetic objective lens in parallel is provided inside the pole piece 31a. The lower pole piece 31b is stage 1
Because it faces the wafer (not shown) mounted on 1. The stage 11 is a temporary structure made of ceramic whose surface is coated with a metal layer as in the conventional stage, and a drive mechanism (not shown) is used.
It is possible to move in the XX direction.

Most of the structure of the magnetic objective lens shown in FIG. 2 is the same as the conventional magnetic objective lens shown in FIG. 7, but as more clearly seen in the plan view of FIG. The shape of the bore is completely different from the conventional example. That is, the bore 33b according to the present invention shown in FIG.
The bore 103b of the conventional pole piece shown in the figure is circular. The dimensions, position, and orientation of the bore 33b are as follows.

While the bore 33b allows the electron beam B to pass through during scanning, it is determined so that most of the magnetic flux within the magnetic objective lens is blocked by the tall lower pole piece 31b and does not cross the stage 11.

For example, if the predetermined scan span is 'l mm and the segmented area is 1
In the case of 00 micron square, the above-mentioned dimensions of the bore 33b are: L=20-40 mm, L=4-6 mm
It is. The reason why the size of the slit-shaped bore 33b is larger than that of the scanning space is because the lower pole piece 31b is made of ferrite, which is ferromagnetic and has a small residual magnetic hysteresis but is easy to machine.

FIG. 4 is a perspective view including a plan view of the main parts of the magnetic objective lens shown in FIG. 2, and shows the positional relationship between the electron beam B and the element parts of the magnetic objective lens. The electron beam B projected from above is doubly deflected by the coil pair 34a and 34b, and is projected onto the lower pole piece 31b parallel to and offset from the axis A. The magnetic objective lens is a coil 90. Although it is shaped by the pole pieces 31a and 31b, it is shifted by the compensation coil 34c so as to coincide with the path of the deflected electron beam B at the same time as the electron beam B is deflected. The control of each coil described above is performed by a central computer (CPU) not shown.

As a result, the electron beam B passes through the slit-shaped bore 33b and is projected vertically onto a wafer (not shown) without being affected by the aberration of the magnetic objective lens.

In terms of the above point lengths, it can be said that it has the same effect as the conventional VAL or VAIL type magnetic objective lens.

However, in the electron beam exposure apparatus according to the present invention, as described above, the stage 11 is constantly moving in the X direction, so it is necessary to pay attention to the magnetic flux that intersects the stage 11.

Figures 5(a) and 5(b) each show a slit-shaped bore 3.
3b are partially enlarged cross-sectional views in the X direction and the X direction, showing the distribution state of the magnetic flux 40 radiated from within the magnetic objective lens. Most of the magnetic flux 40 is at the lower pole piece 3
It is blocked and absorbed by 1b.

On the other hand, among the magnetic flux 40 projected to the bore 33b, a very small amount of the magnetic flux 40a passes through the slit-shaped bore 33b and is projected onto the wafer 10, and the other considerable part of the magnetic flux 40 is
It is shown in FIG. 5(b) that it is absorbed into the side wall of the bore 33b perpendicular to the surface of the pole piece 31b. This is a unique function of the slit-like bore 33b formed according to the invention.

In the above description, there is no fourth coil, that is, the second compensation coil, but the bore 33b in the longitudinal direction of FIG.
A compensation coil for deflecting the electron beam B in the direction of deflection, that is, in the Y direction, can be provided on the side wall 33d.

FIG. 6 is a perspective view showing the above-mentioned structure, and shows a pattern in which a pair of compensation coils 35 are arranged on a longitudinal side wall 33d of a slit-shaped bore 33b provided in a lower pole piece 31b. The compensation coil 35 is formed of several turns of copper wire, and is driven in synchronization with the deflection of the electron beam B, as described above, to promote convergence of the -layer electron beam B.

In each of the above-described embodiments, the electron beam B is deflected in a plane that includes the optical axis X of the magnetic lens system in one direction (for example, the Y-axis direction), that is, the scanning operation is not limited to this. , even when the scanned area is expanded two-dimensionally in the X and Y directions.

It will be obvious to those skilled in the art that the present invention is applicable. That is, the shape of the opening of the bore of the lower pole piece is formed to include the area to be scanned and the bore is as narrow as the processing technology allows, and at the same time the electron beam is projected through the bore and the electron beam is projected from within the magnetic objective lens. Block the magnetic flux as much as possible with the lower pole piece,
Reduces eddy currents generated within the moving stage and improves electron beam convergence. A magnetic objective lens structure can be formed.

Further, in each of the above-mentioned embodiments, a continuous stage movement method was described in which the stage constantly moves in one direction during exposure using an electron beam exposure apparatus. It is clear that the present invention can also be applied to a beam exposure method. That is, as long as the stage moves, whether it is continuous or intermittent,
If the magnetic flux crosses the stage, eddy currents will be generated within the stage. This is because this eddy current can be effectively reduced by adopting the shape of the bore provided in the lower pole piece according to the present invention.

〔Effect of the invention〕

As is clear from the above description, 2) the magnetic flux leaking from the magnetic objective lens used in the magnetic lens system of the electron beam exposure apparatus according to the present invention toward the exposed object, such as a semiconductor wafer, is minimized; Since the eddy current is suppressed and reduced, the eddy current generated in the stage on which the object is mounted due to the movement of the stage is significantly reduced. As a result, the harmful magnetic flux outside the control of the central electronic computer generated by the eddy current is reduced, and the conventional problem of reducing the degree of convergence of the electron beam focused by the magnetic lens system is solved, and the Beam exposure equipment can easily create highly accurate and high resolution circuit patterns on semiconductor objects such as wafers.

[Brief explanation of the drawing]

FIG. 1 shows an electron beam exposure apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view of a main part of a magnetic objective lens according to the present invention. 3 is a plan view of the lower pole piece of the magnetic objective lens shown in FIG. 2; FIG. FIG. 4 is a perspective view including a sectional view of a main part of the magnetic objective lens shown in FIG. 2; Figures 5(a) and 5(b) each show a slit-shaped bore 3.
3b is a partially enlarged cross-sectional view in the X direction and the Y direction. FIG. 6 is a perspective view showing the structure of a compensation coil provided on the side wall of the bore 133b. FIG. 7 is a sectional view of a main part showing the structure of a magnetic objective lens of a conventional electron beam exposure apparatus. FIG. 8 is a partially cutaway perspective view of the conventional magnetic objective lens shown in FIG. 7. In the figure, 8a, 8b, 34a. 8c, 34c, 35 10... 11.107... 31a, 1ota, 31b, 101b, 33b, 103b, 40.40a... 50.105... 90.102... A・・・・・・・・・B ・・・・・・・・・ is shown respectively. b... Deflection coil. ...Compensation coil.・Semiconductor wafer. ·stage. - Upper pole piece.・Lower pole piece.・Boa.・Magnetic flux.・External shield.・Lens coil.・Magnetic lens system optical axis.・Electron beam

Claims (6)

[Claims] (1) Electron convergence that includes a stage on which the object to be processed is mounted and can move continuously in at least one predetermined movement direction, an electron emitting means and a magnetic objective lens, and converges the electrons and forms them into an electron beam. and a magnetic lens system having an electron beam deflection means for deflecting the electron beam, scanning the electron beam in a scanning space extending in at least one direction so as to continuously move the electron beam in the predetermined movement direction. The electron beam exposure apparatus projects the electron beam onto the moving object, and the magnetic objective lens includes a coil that generates a magnetic flux, an upper pole piece made of a magnetic material, and an upper pole piece made of a magnetic material. a lower pole piece disposed opposite to the object to guide the magnetic flux; the lower pole piece allows the electron beam to pass through a portion of the lower pole piece corresponding to the scanning space of the electron beam; An electron beam exposure apparatus characterized by having a bore provided to prohibit passage of leaking magnetic flux. (2) The electron beam exposure apparatus according to claim 1, wherein the scanning direction of the electron beam and the moving direction of the stage are orthogonal to each other. (3) The electron beam exposure apparatus according to claim 1, wherein the bore provided in the lower pole piece has a slit shape extending in the scanning direction of the electron beam. (4) The electron beam exposure apparatus according to claim 1, wherein the bore provided in the lower pole piece has a rectangular shape extending in the scanning direction of the electron beam. (5) The electron beam exposure apparatus according to claim 1, wherein the object is a semiconductor wafer. (6) An electron beam exposure device that scans an electron beam within a limited scanning space extending in at least one direction and irradiates the electron beam onto a target mounted on a moving stage, the target being A lower pole piece is provided opposite to the lower pole piece, and a bore is formed in the lower pole piece to correspond to the limited scanning space of the electron beam and to allow the electron beam to pass therethrough. An electronic exposure apparatus comprising: