JPH0513200A - Method for enlarging exposed area of sor - Google Patents

Abstract

PURPOSE:To enlarge an electron beam inside an accumulation ring in the vertical direction without additionally installing a special equipment and prevent a lifetime of the electron beam from being shortened in exposing operation where SOR are used as a light source. CONSTITUTION:A beam size controller 32 controls a magnetic field of a skew quadrupole electromagnet 27 in a pulse mode in order to adjust a ratio of a vertical beam size to a lateral beam size of an electron beam 11 of an accumulation ring 22, so as to enlarge a beam profile of the electron beam 11 in the vertical direction only during exposure. Consequently, SOR 29 wide in the horizontal direction is enlarged in the vertical direction during the exposure so that a required exposed area can be secured by an exposing device 28. Simultaneously, a relative distance from the wall of the accumulation ring 22 is increased for a time other than the exposure time, thus solving a problem of a lifetime.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure area enlarging method in the case of performing exposure during the manufacturing process of a VLSI using SOR light (synchrotron radiation), and it is an electronic method without special equipment. The beam can be expanded in the vertical direction and the influence on the life of the electron beam can be reduced.

[0002]

2. Description of the Related Art SOR light is a strong light ray such as X-ray emitted from a deflection position of an electron beam that orbits a storage ring in a synchrotron, and is applied to a light source for exposure in a VLSI manufacturing process. Is expected. SOR
In the exposure using light, generally, SOR light is guided from the electron beam deflection position of the synchrotron to a light extraction line branched in the tangential direction, and emitted from a window provided at the end of this light extraction line, This is performed by irradiating the semiconductor wafer through the substrate of the LSI exposure mask. Since this SOR light has a large width in the horizontal direction but a narrow width in the vertical direction, it is necessary to secure an exposure area in the vertical direction by expanding the SOR light in the vertical direction.

As one of the methods for expanding the SOR light in the vertical direction, there is a so-called electron beam vibration method. This is because an electromagnet for oscillating the electron beam in the vertical direction is arranged in the storage ring, and the amount of excitation is changed with time to give a vertical deflection to the electron beam to oscillate, thereby causing the SOR light to move vertically. It was designed to be enlarged.

[0004]

The above-mentioned conventional electron beam vibration method requires an electromagnet for oscillating the electron beam. However, in a compact synchrotron, a bending electromagnet, a focusing electromagnet, various correction electromagnets, various measuring devices, etc. are already installed in the storage ring, so it is difficult to add a separate electromagnet for electron beam oscillation in terms of space. Therefore, if the synchrotron is installed from the beginning of design, the synchrotron becomes large. On the other hand, if the electron beam in the storage ring is vertically swung or expanded, the relative distance between the electron beam and the wall surface of the vacuum chamber that constitutes the storage ring becomes closer, increasing the probability that the electron beam will hit the wall surface and increasing the service life. There is a problem that is shortened.

The present invention solves the above-mentioned problems in the prior art and allows the electron beam to be expanded without additionally adding an electromagnet or the like for expanding the electron beam, and the life of the electron beam is shortened. It is intended to provide a method for enlarging the exposure area of SOR light which can be prevented.

[0006]

According to the method of enlarging the exposure area of SOR light of the present invention, the light extraction line is branched in the tangential direction from the deflection position of the storage ring on which the electron beam is orbiting, and the SOR light is When the object to be exposed is extracted from the light extraction line, a skew quadrupole electromagnet that adjusts the aspect ratio of the electron beam size arranged in the storage ring is used for exposing the object to be exposed during the exposure of the object to be exposed. It is characterized in that exposure is performed while driving so as to increase the size in the vertical direction. Further, in the method for enlarging the exposure area of SOR light of the present invention, the light extraction line is branched in the tangential direction from the deflection position of the storage ring in which the electron beam is orbiting, and the SOR light is extracted from this light extraction line, When exposing the exposure target, the ion sweep electrode for sweeping the ions of the residual gas disposed in the storage ring is driven so as to increase the vertical size of the electron beam during the exposure of the exposure target. It is characterized by exposing while exposing.

[0007]

According to the SOR light exposure area expansion method, the synchrotron is provided with a skew quadrupole electromagnet for adjusting the aspect ratio of the beam size of the electron beam in the storage ring. Along with realizing the vertical expansion of the electron beam by using the magnetic field of the polar electromagnet, this expansion of the electron beam is performed only during the exposure to minimize the time when the relative distance to the storage ring wall becomes short. I have to.

According to this, since the skew quadrupole electromagnet is also used for expanding the electron beam, it is not necessary to separately provide an electromagnet for expanding the electron beam, the problem of the space for disposing the storage ring is solved, and at the same time, the storage is performed. Reducing the probability of hitting the ring wall also solves the problem of life.

Further, according to this method for expanding the exposure area of SOR light, the residual gas in the storage ring collides with the electron beam and stays as ions in the synchrotron, and the electron beam spreads by attracting the electron beam. In order to prevent this, an ion sweep electrode for removing this ion is provided, and the electric field by this ion sweep electrode is used to realize vertical expansion of the electron beam, and at the same time, the expansion of this electron beam is exposed. The time during which the relative distance to the storage ring wall becomes short is reduced as much as possible.
According to this, since the ion sweep electrode is also used for expanding the electron beam, it is not necessary to provide a separate device for expanding the electron beam, the problem of the arrangement space for the storage ring is solved, and at the same time, the probability of hitting the storage ring wall Also, the problem of life is solved by reducing.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an SO to which the present invention is applied.
1 shows an outline of an R optical device. In the SOR optical device 1, an electron beam 11 generated by an electron generator (electron gun or the like) 10 is accelerated by a linear accelerator (linac) 12 to a speed close to the speed of light, and is deflected by a deflection electromagnet 16 of a beam transport unit 14 to produce an inflector. It is injected via 18 into the storage ring 22 of the synchrotron. The electron beam 11 incident on the storage ring 22 is provided with energy in the high-frequency acceleration cavity 21, and the focusing electromagnets 23, 2 arranged on each straight line portion are given energy.
5 (23 is for vertical, 25 is for horizontal) is converged to the central position in the storage ring 22, and a skew quadrupole electromagnet 27 for adjusting beam size is provided in two straight portions facing each other. The aspect ratio of the beam size is adjusted, and the beam is deflected by the deflection electromagnet 24 to continue to orbit the storage ring 22.
The SOR light 29 emitted in the tangential direction when being deflected by the deflection electromagnet 24 is emitted through the light extraction line 26 and sent to the exposure device 28 to be used as an exposure X-ray light source for making an LSI circuit. It

When the circulating electrons hit the residual gas in the storage ring 22, the residual gas becomes positive ions and floats, and the positive ions of this gas attract the electrons and prevent the electron beam 11 from spreading. Therefore, as shown in FIG. 3, an ion sweep electrode 30 is provided in the straight portion of the storage ring 22, and a negative electric field is formed by the ion sweep electrode 30 to attract positive ions of the residual gas. It is supposed to be removed.

The SOR light 2 in such a SOR light device 1
As a method of expanding the exposure area of the electron beam 9, the skew quadrupole electromagnet 27 that adjusts the aspect ratio of the beam size of the electron beam 11 in the storage ring 22 is used, and the magnetic field thereof is controlled to increase the beam size of the electron beam 11 vertically. Spread in the direction. That is, the cross-sectional shape of the electron beam 11 that normally circulates in the storage ring 22 corresponds to the racetrack type cross section of the vacuum chamber 31 that constitutes the storage ring 22, as shown in the normal operation state in the upper part of FIG. Then, the magnetic field is controlled by the beam size control device 32 so as to form a laterally wide elliptical shape. However, when the exposed area of the SOR light 29 is enlarged, the exposure area enlarged state is shown at the bottom of FIG. Then, the magnetic field is controlled by the beam size control device 32 so that the aspect ratio of the cross-sectional shape of the electron beam 11 is reversed. As a result, the electron beam 11 which is originally wide in the horizontal direction can be expanded in the vertical direction to expand the exposure area.

When the beam profile of the electron beam 11 is expanded in the vertical direction in this way, the electron beam 11 is scattered because the relative distances to the upper and lower wall surfaces of the vacuum chamber 31 of the racetrack type cross section which constitutes the storage ring 22 become closer. As a result, the probability of collision with the wall surface is increased and the life is shortened. On the other hand, when exposing a VLSI,
As shown in FIGS. 5 and 6, in the exposure device 28 at the tip of the light extraction line 26, using the exposure mask 34 in which a large number of patterns 33 are formed side by side, each pattern is moved while the SOR light 29 or the semiconductor wafer 35 is moved. The SOR light 29 is guided to and exposed at 33, and there is a movement time of a device such as a stepper between one exposure and the next exposure.

Therefore, in this exposure area expansion method, SOR
The beam profile of the normal electron beam 11 is kept as it is (see the upper side of FIG. 2) during the moving time in which the exposure area of the light 29 does not need to be expanded, and the SOR light 29 is kept only during the exposure.
The exposure area is expanded (see the lower side of FIG. 2). That is, a control signal for expanding the beam profile in the vertical direction from the beam size control device 32 is sent in a pulse to the skew quadrupole electromagnet 27, and the magnetic field generated by the skew quadrupole electromagnet 27 is changed in a pulsed manner. As shown in FIG. 5, exposure is performed for 1 second, movement is performed for the next 1.5 seconds, and exposure is performed again for 1 second.

As a result, the beam profile of the electron beam 11 is expanded in the vertical direction only during the exposure,
At other times, the normal beam profile remains wide and the relative distance to the wall surface of the vacuum chamber 31 is large, and the probability of hitting the wall surface of the vacuum chamber 31 due to scattering of the electron beam 11 is reduced and the life is extended. Prevent the effects of. Further, since the skew quadrupole electromagnet 27 is also used for expanding the beam profile of the electron beam 11 in the vertical direction, it is not necessary to separately provide an electromagnet for expanding the electron beam, and the problem of the space for disposing the storage ring 22 is solved. To be done.

Next, another method for expanding the exposure area of the SOR light 29 in the SOR light device 1 will be described. This S
In the method of enlarging the exposure area of the OR light, the residual gas in the storage ring 22 becomes positive ions and floats, and the positive ions attract the electrons to prevent the electron beam 11 from spreading. The electric field is controlled by the ion sweep controller 36 to expand the beam size of the electron beam 11 in the vertical direction.

The ion sweep electrode 30 is used for the storage ring 2
When the energy of the electron is low and the momentum is small, such as when the electron is incident on 2, it is used because it is necessary to remove the positive ions because the electrons are easily disturbed by the floating ions. In a high state, the momentum is large and the influence of floating ions is small, and the electron beam 11
In many cases, the ion sweep electrode 30 is not used in the storage state of 1, and there is no problem in using it other than the ion sweep during exposure.

Therefore, a storage ring 22 for the electron beam 11
In the storage state, the unused ion sweep electrode 30 is used, and the ion sweep control device 36 controls the ion sweep electrode 30 so that the exposure area is expanded to the lower side of FIG. Contrary to the above (see above), a control signal is sent to a power supply device (not shown) so as to form a positive electric field, and the electron beam 11 is applied to the ion sweep electrodes 30 arranged above and below at least one linear portion of the storage ring 22, for example. The beam profile is expanded in the vertical direction by pulling. As a result, the electron beam 11 which is originally wide in the horizontal direction can be expanded in the vertical direction, and the exposure area of the SOR light 29 can be expanded.

As described above, the electron beam 1
When the beam profile of No. 1 is expanded in the vertical direction, the relative distance to the upper and lower wall surfaces of the vacuum chamber 31 of the racetrack type cross section forming the storage ring 22 becomes closer, so that the probability of hitting the wall surface due to scattering of the electron beam 11 increases. Life will be shortened. On the other hand, the exposure of the VLSI or the like is not necessarily performed continuously as described with reference to FIGS. 5 and 6, and one pattern 33 of the exposure mask 34 is exposed for about 1 second, and the next pattern is exposed for about 1.5 seconds. Pattern 33
After moving to, the next pattern 33 is exposed,
There is a movement time of a device such as a stepper between each exposure.

Therefore, even in the exposure area enlarging method using the ion sweep electrode 30, the beam profile of the normal electron beam 29 remains as it is during the moving time during which the exposure area of the SOR light 29 does not need to be enlarged (see FIG. 3). (See the upper side), and the exposure area of the SOR light 29 is enlarged only during the exposure (see FIG. 3).
See below). That is, a control signal for expanding the beam profile in the vertical direction from the ion sweep control device 36 is sent in a pulsed manner to a power supply device (not shown), the ion sweeping electrode 30 is driven in a pulsed manner, and exposure is performed for 1 second, for example. It is a pulse drive for 2.5 seconds in which the movement is repeated for the next 1.5 seconds and the exposure is performed again for 1 second.

As a result, the beam profile of the electron beam 11 is expanded in the vertical direction only during the exposure,
At other times, the normal beam profile is maintained and the relative distance to the wall surface of the vacuum chamber 31 is large, and the vacuum chamber 3 is caused by scattering of the electron beam 11 or the like.
The probability of hitting the wall surface of No. 1 can be reduced, and the influence on the life of the electron beam 11 can be prevented as much as possible. Also, the ion sweep electrode 3
Since 0 is also used to expand the beam profile of the electron beam 11 in the vertical direction, it is not necessary to separately provide a device such as an electromagnet for expanding the electron beam, and the problem of the space for disposing the storage ring 22 is solved.

By using the electron beam 11 expanded in the vertical direction as described above, as shown in FIG.
One pattern 33 of the exposure mask 34 in the inside can be completely exposed to the semiconductor wafer 35 by irradiation once, and the exposure can be performed efficiently.

[0023]

As described above in detail with reference to the embodiments, according to the method for enlarging the exposure area of SOR light of the present invention, the magnetic field generated by the skew quadrupole electromagnet for adjusting the aspect ratio of the beam size of the electron beam is changed. Since the vertical expansion of the electron beam is realized by utilizing this, and at the same time, the expansion of the electron beam is performed only during the exposure, there is no need to provide a separate electromagnet for expanding the electron beam, and The problem of the arrangement space is solved, and at the same time, the problem of life is solved by reducing the time when the relative distance to the storage ring wall becomes short as much as possible.

Further, according to the SOR light exposure area expansion method of the present invention, the vertical expansion of the electron beam is realized at the same time by utilizing the electric field by the ion sweep electrode for removing the gas ions remaining in the storage ring. Since the expansion of the electron beam is performed only during the exposure, it is not necessary to provide a separate device for expanding the electron beam, and the problem of the space for arranging the storage ring is solved, and at the same time, the storage ring wall and The problem of life is solved by reducing the time when the relative distance of is shortened as much as possible.

[Brief description of drawings]

FIG. 1 is a plan view showing an outline of a SOR light device to which an embodiment of an SOR light exposure area enlarging method of the present invention is applied.

FIG. 2 is an explanatory diagram when a skew quadrupole electromagnet according to an embodiment of the method for enlarging the exposure area of SOR light of the present invention is used.

FIG. 3 is an explanatory diagram when an ion sweep electrode according to another embodiment of the method for enlarging the exposure area of SOR light of the present invention is used.

FIG. 4 is an explanatory diagram of a relationship (pulse driving) between exposure and exposure area enlargement according to an embodiment of an SOR light exposure area enlargement method of the present invention.

FIG. 5 is a sectional view of an exposure state according to an embodiment of the method for enlarging the exposure area of SOR light according to the present invention.

FIG. 6 is a front view of an exposure target according to an embodiment of the method for enlarging the exposure area of SOR light according to the present invention.

[Explanation of symbols]

11 Electron Beam 22 Storage Ring 24 Deflection Electromagnet 26 Light Extraction Line 27 Skew Quadrupole Electromagnet 28 Exposure Device 29 SOR Light 30 Ion Sweep Electrode 31 Vacuum Chamber 32 Beam Size Control Device 33 Patterns 34, 35 Exposure Mask and Semiconductor Wafer (Exposure Target) ) 36 Ion sweep controller

Claims (2)

[Claims] 1. A light extraction line is branched in a tangential direction from a deflection position of a storage ring around which an electron beam is circulated, and SOR light is extracted from the light extraction line to expose the object to be exposed. The skew quadrupole electromagnet that adjusts the aspect ratio of the electron beam size arranged in the ring is exposed while being driven so as to increase the vertical size of the electron beam while the exposure target is being exposed. And SOR light exposure area expansion method. 2. An electron beam is branched from a deflected position of a storage ring around which an electron beam is circulated in a tangential direction thereof, and SOR light is extracted from the light extraction line to expose the object to be exposed. The SOR is characterized in that the ion sweep electrode for sweeping the ions of the residual gas disposed in the ring is exposed while being driven so as to increase the vertical size of the electron beam during the exposure of the exposure target. Light exposure area enlargement method.