JPH04229999A - Exposure of sor beam - Google Patents

Abstract

PURPOSE:To secure a necessary exposure surface in the vertical direction in exposure using an SOR beam unit by deflecting an SOR beam vertically. CONSTITUTION:A superconductive wiggler 35 having magnetic poles facing each other with a linear part 31 of a storage ring 22 between them is disposed on the outer side of the linear part 31, so an electron beam 11 in the storage ring 22 is let to meander vertically. An SOR beam is thus sent from a turning position of each meander of the electron beam to be guided through a beam taking line 26 to an exposure device. At this time, an excitation quantity controlling device 52 changes an excitation quantity of the superconductive wiggler 35 by time. An amplitude of the meander of the electron beam 11 is thus changed, and the SOR beam is deflected vertically, thereby a necessary exposure surface in the vertical direction can be secured.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure method using SOR light (synchrotron radiation), in which exposure is performed by swinging the SOR light in the vertical direction using a superconducting wiggler.

0002

[Prior Art] SOR light is a powerful light beam such as X-rays emitted from the deflection position of an electron beam orbiting a storage ring in a synchrotron, and is applied to light sources for exposure in the VLSI manufacturing process. is expected. SOR
Exposure using light generally involves guiding SOR light from the electron beam deflection position of a synchrotron to a light extraction line branched in the tangential direction, and emitting it from a window provided at the end of this light extraction line. This is done by irradiating the semiconductor wafer through the substrate of an LSI exposure mask. In this case, since the SOR light has a wide width in the horizontal direction but a narrow width in the vertical direction, the exposure area in the vertical direction must be ensured by swinging the SOR light in the vertical direction. Conventional methods for vertically swinging SOR light include a mirror swing method and an electron beam vibration method.

[0003] In the conventional mirror swing method, an oblique incidence mirror is arranged in the SOR light extraction line to reflect the SOR light, and by swinging this mirror, the SOR light is swung in the vertical direction. . In addition, the electron beam vibration method
An electromagnet for oscillating the electron beam is placed in the storage ring, and by changing the direction and amount of excitation, the electron beam is oscillated in the vertical direction, and the SOR light is accordingly swung vertically. be.

0004

[Problems to be Solved by the Invention] In the mirror rocking method, since the mirror is rocked in a vacuum, it is not possible to use grease on the rocking shaft to prevent gas generation, and the rocking shaft gets stuck and does not move. There was a risk. Also, it was difficult to vacuum seal the external swing mechanism. Furthermore, it was not possible to increase the SOR light intensity. Furthermore, although there is no mechanically moving part in the electron beam swinging method, it was possible to increase the SOR light intensity as in the mirror swinging method.

[0005] The present invention solves the problems in the conventional technology, and provides an SOR light that does not require a moving part in a vacuum to vertically swing the SOR light, and can increase the SOR light intensity. The present invention attempts to provide an exposure method.

[0006]

[Means for Solving the Problems] The present invention comprises a plurality of sets of superconducting coils placed outside a straight section of a storage ring, sandwiching the straight section, and facing each other in a substantially horizontal direction with their magnetic poles alternately reversed. The method is characterized in that a superconducting wiggler is arranged, and the SOR light emitted from the superconducting wiggler is extracted and exposed on an extension of the straight portion while changing the gap between the magnetic poles of the superconducting wiggler over time. be.

[0007]

[Operation] According to the present invention, by arranging the magnetic poles of the superconducting wigglers on the outside of the storage ring so as to face each other in a substantially horizontal direction, the electron beam in the straight section meanders in a substantially vertical direction. Emit SOR light at each turning position,
Exposure is performed by taking out an extension of the straight part. At this time, by changing the amount of excitation of the superconducting wiggler over time, the strength of the magnetic field acting on the electron beam changes, and the amplitude of the meandering of the electron beam changes. As a result, the vertical position at which the SOR light is emitted changes, the SOR light is swayed in the vertical direction, and the necessary exposure area in the vertical direction is secured.

According to this, since the superconducting wiggler is placed outside the storage ring, there is no need for any parts that move in vacuum.Moreover, since the superconducting wiggler is used, a powerful SO
R light can be obtained, the exposure speed can be increased, and the exposure efficiency can be increased.

[0009]

[Embodiment] An embodiment of the present invention will be described below. FIG. 1 shows an outline of an SOR optical device to which the present invention is applied. In the SOR optical device 1, an electron beam 11 generated by an electron generator (electron gun, etc.) 10 is accelerated to near the speed of light by a linear accelerator (linac) 12, and then transferred to the beam transport section 1.
The beam is deflected by the deflection electromagnet 16 of No. 4, and is incident into the storage ring 22 of the synchrotron via the inflector 18. The electron beam 11 incident on the storage ring 22 is energized by the high frequency acceleration cavity 21 and moves through each linear section 31.
It is focused by a focusing electromagnet (not shown) disposed at 34, passes through the center of the storage ring 22, is deflected by a deflecting electromagnet 24, and continues to circulate within the vacuum duct 22. Straight section 3
1 is provided with a superconducting wiggler 35, and a straight portion 31
A light extraction line 26 is connected to the extension of the line 26 and guided to an exposure device 28 .

The detailed structure of the superconducting wiggler 35 is shown in a plan view in FIG. Further, a view taken along the line AA in FIG. 2 is shown in FIG. 3, and a view taken along the line BB in FIG. 2 is shown in FIG. The superconducting wiggler 35 is attached to the outside of the straight part 31 of the storage ring 22.
An odd number of superconducting coils 40 and 41 with different polarities are arranged with the polarities alternately placed between the storage ring 22 to apply a horizontal magnetic field 37 whose direction changes alternately to the electron beam 11 in the storage ring 22. As a result, the electron beam 11 meanders in the vertical direction, and emits SOR lights 29 and 30 in the direction of the light extraction line 26 at each turning position of each meandering, that is, at each upper and lower peak position of the vibration amplitude. In addition,
The reason why the superconducting coils 40 and 41 are set to an odd number is as follows.
This is to return the electron beam 11 to its original orbit at the exit of the superconducting wiggler 35. The SOR lights 29 and 30 emitted at the peak position of each vibration amplitude are successively interfered and intensified each time they meander, and are emitted from the superconducting wiggler 35 and guided to the exposure device 28 through the light extraction line 26. used for exposure.

The amount of excitation of the superconducting coils 40 and 41 constituting the superconducting wiggler 35 is controlled by an excitation amount control device (FIG. 1).
can be changed over time.

When the amount of excitation is changed, the strength of the magnetic field 37 acting on the electron beam 11 in the storage ring 22 changes, thereby changing the amplitude of the meandering of the electron beam 11. That is, when the amount of excitation is large, the magnetic field 37 acts strongly on the electron beam 11, and the amplitude of the meandering becomes large. Furthermore, when the amount of excitation is small, the magnetic field 37 acts weakly on the electron beam, and the amplitude of meandering becomes small. As a result, the vertical position of the generation of the SOR lights 29 and 30 also changes. Therefore, if the excitation amount is changed over time by the excitation amount control device 52, the SO
The R light beams 29 and 30 are swung in the vertical direction to ensure an exposed area in the vertical direction.

FIG. 5 shows the meandering state of the electron beam 11 and the exposure state when the amount of excitation is changed. When the amount of excitation is large, the magnetic field 37 acts strongly, so the electron beam meanderes with a large amplitude as shown by the solid line 11, and emits SOR lights 29 and 30 at the upper and lower peak positions. At this time, the light intensity distribution in the vertical direction on the X-ray mask substrate and the semiconductor wafer 54 has a large light intensity at the top and bottom and a small light intensity at the center, as shown by the solid line on the right side. On the other hand, when the amount of excitation is small, the magnetic field 37
acts weakly, so the electron beam meanders with a small amplitude as shown by the dotted line 11', and the SOR light 2 at the upper and lower peak positions.
9' and 30' are emitted. This SOR light 29', 30'
Since the distance between them in the vertical direction is short, the light intensity distribution in the vertical direction on the X-ray mask substrate and semiconductor wafer 54 at this time is small at the top and bottom and large at the center, as shown by the dotted line on the right. Therefore, by conveniently setting the range of change in excitation amount control and the rate of change in the excitation amount by the excitation amount control device 32, it is possible to uniformly expose the entire surface of the X-ray mask substrate and the semiconductor wafer 54 in the vertical direction. Note that exposure of one semiconductor wafer is completed by changing the excitation amount from large to small or from small to large in one step or multiple steps.

[0014]

[Modification example] In the above embodiment, the superconducting wiggler 35 was arranged only in one straight part 31, but the superconducting wiggler 35 was arranged only in one straight part 31,
, 34, and the excitation amount can be changed and controlled synchronously or asynchronously.

[0015]

[Effects of the Invention] As explained above, according to the present invention, the magnetic poles of the superconducting wigglers are placed on the outside of the storage ring so as to face each other in a substantially horizontal direction, and the amount of excitation thereof is changed over time. Therefore, the SOR light is swayed in the vertical direction, and the necessary exposure area in the vertical direction can be secured. According to this, since the superconducting wiggler is placed outside the storage ring, there is no need for any parts that move in vacuum.Moreover, since the superconducting wiggler is used, a powerful SO
R light can be obtained, the exposure speed can be increased, and the exposure efficiency can be increased.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and is a plan view showing an outline of an SOR optical device.

FIG. 2 is a plan view showing the detailed configuration of the superconducting wiggler in FIG. 1;

FIG. 3 is a view taken along the line AA in FIG. 2;

FIG. 4 is a view taken along the line BB in FIG. 2;

FIG. 5 is a diagram showing the meandering state of an electron beam and the state of exposure when the amount of excitation of the superconducting wiggler is changed.

[Explanation of symbols]

1 SOR optical device 22 Storage ring 26 Light extraction line 28 Exposure device 29 SOR light 30 SOR light 31 Straight section 32 Straight section 33 Straight section 34 Straight section 35 Superconducting wiggler 40,41 Superconducting coil 52 Excitation amount control device G Gap

Claims (1)

[Claims] [Claim 1] A superconducting wiggler is disposed outside the straight part of the storage ring, and the superconducting wiggler is composed of a plurality of sets of superconducting coils with their magnetic poles alternately reversed and facing each other in a substantially horizontal direction, sandwiching the straight part. A method for exposing SOR light, which comprises extracting and exposing the SOR light emitted from the superconducting wiggler onto an extension of the straight portion while changing the gap between the magnetic poles of the superconducting wiggler over time.