JPH04237113A - Radiation ray aligner - 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]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation exposure apparatus used for manufacturing semiconductor devices, and more particularly to the structure of a light extraction portion. In recent years, as semiconductor devices have become more highly integrated and densely packed, patterns handled in lithography processes have become increasingly finer, and pattern transfer technology in X-ray exposure has attracted attention.

As for X-ray exposure methods, methods using synchrotron radiation are being studied. Compared to methods using conventional X-ray tubes, this method has higher X-ray intensity, which improves throughput, and because of its high parallelism, there is no penumbra blurring, making it possible to transfer finer patterns. Attention has been paid.

0003

2. Description of the Related Art FIG. 4 is a diagram showing the principle of a synchrotron radiation generator. In the figure, 1 is an injector, 2 is a charged particle storage ring consisting of a deflection magnet 3, a high-frequency cavity 4, and a vacuum duct 5, and 6 is an outlet for synchrotron radiation 7. The charged particles entering the charged particle storage ring 2 from the injector 1 are deflected in their traveling direction by the deflection magnet 3 and circulate within the charged particle storage ring 2, and a high frequency voltage is applied in synchronization with the rotation of the charged particles. Energy is given each time the beam passes through the high-frequency cavity 4, and synchrotron radiation is finally generated. Since this emitted light is not deflected by the magnet, it is extracted from the emitted light extraction port 6 in the deflection magnet section 3. This radiation light 7 is taken into a radiation exposure apparatus shown in FIG.

The radiation exposure apparatus shown in FIG.
1, S2, gate valve GV1, GV2, turbo pump TP1, TP2, ion gauge IG1, IG2
, IG3 and a vacuum duct 9 provided with a Be window 8 for taking out X-rays, and a differential pumping system 10 in the vacuum duct 9.
A sample chamber 11 is connected to the sample chamber 11 via a sample chamber. The sample chamber 11 accommodates an X-ray mask 12 and a wafer 13, and is kept in a low vacuum or around atmospheric pressure with an inert gas such as He to prevent the X-ray mask 12 from absorbing radiation and being heated. is maintained. Furthermore, the Be window 8 is made of metal that allows X-rays to pass through easily. Be is used to isolate the vacuum between the vacuum duct 9 on the light source side and the sample chamber 11, and to allow X-rays to pass from the light source to the sample chamber 11.

The differential pumping system 10 also includes a plurality of slit plates 1.
4 and a plurality of exhaust pumps 15, and is provided for the following reasons. That is, the intensity of the Be window 8 increases as its thickness increases, but out of the X-rays emitted from the light source, long wavelength components that are easily absorbed by substances (weak penetrating power) are absorbed, and X-rays become It becomes difficult to maintain the contrast of the mask 12 (the difference in intensity of transmitted X-rays between a portion where X-rays are to be blocked and a portion where X-rays are to be transmitted). Therefore, Be from the sample chamber 11
The area leading to the window 8 is differentially pumped so that the pressure on the Be window side is low to weaken the force applied to the Be window 8, and to create a thin Be window.
The windows are available for use.

[0006]

In the conventional radiation exposure apparatus described above, each slit plate 14 is mounted perpendicularly to the optical axis 16 of the X-rays. Therefore, the flow of gas ejected from the high-pressure side to the low-pressure side of the slit plate 14 is almost perpendicular to the slit plate 14, so this gas flow easily passes through the next slit plate, making it difficult to create a pressure difference. Become. Therefore, a large number of slit plates are required to obtain the necessary pressure difference. As a result, the distance from the light source to the sample chamber 11 becomes longer, and the apparatus becomes larger. Moreover, since the X-rays spread, there are problems such as the X-ray intensity per unit area on the sample surface becoming weaker.

The present invention aims to realize a radiation exposure apparatus that reduces the number of slit plates in a differential pumping system, thereby making it possible to downsize the apparatus and prevent a decrease in X-ray intensity.

[0008]

[Means for Solving the Problems] The radiation exposure apparatus of the present invention includes a vacuum duct for introducing radiation, a Be window provided in the vacuum duct, a plurality of slit plates in the vacuum duct, and a plurality of exhaust pumps. In a radiation exposure apparatus consisting of a sample chamber connected via a differential pumping system, only the opening of the slit plate is perpendicular to the optical axis of the X-ray, and the portion other than the opening is exposed to the X-ray. It is characterized by being tilted from a plane perpendicular to the optical axis.

[0009]

[Operation] Gas flows through the opening 14a of the slit plate 14 in a direction substantially perpendicular to the slit plate 14. Since the slit plate 14 is inclined, the direction of the gas flow is not parallel to the optical axis 16 of the X-rays, but is oblique. For this reason, since the opening 14a of the next slit plate 14 is separated from the opening 14a of the next slit plate 14, the gas flow becomes turbulent and becomes difficult to flow. Therefore, the differential pressure before and after the slit plate 14 increases,
The number of slit plates 14 can be reduced.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a first embodiment of the present invention. This embodiment includes a vacuum duct 9 provided with slits S1 and S2, gate valves GV1 and GV2, turbo pumps TP1 and TP2, ion gauges IG1 to IG3 and a Be window 8, a differential pumping system 10, and a differential pump system 10. The sample chamber 11 connected to the vacuum duct 9 via the exhaust system 10 is the same as the conventional example explained in FIG. 14.

The slit plate 14 in this embodiment is shown in FIG.
As shown in FIG. 2, the slit opening 14a is perpendicular to the optical axis 16 of the X-rays, but the portion other than the opening 14a is tilted with respect to the plane perpendicular to the optical axis 16 of the X-rays. . In this embodiment configured in this way, the gas flowing through the opening 14a of the slit plate 14 is almost perpendicular to the slit plate 14 as shown by the arrow, as shown in FIG. It is not parallel to the optical axis 16 of the line. Therefore, this gas flow is transferred to the next opening 14a of the slit plate 14.
Since the slit plate 14 deviates from the slit plate 14, turbulence occurs and the flow becomes difficult, and the pressure difference between the front and rear sides of the slit plate 14 becomes large. Therefore, the number of slit plates 14 can be reduced by keeping the pressure difference throughout the differential pumping system the same as in the conventional system.

As a practical example, each slit plate 14 has a thickness of 1
A stainless steel plate with a diameter of 2 mm is used, the size of the opening is 2 mm x 20 mm, the angle between the slit plate and the plane perpendicular to the optical axis of the X-ray is 15 degrees, and the number of plates is 30.
When two rotary pumps with a pumping speed of 500 l/min were used and the pressure in the sample chamber was 100 Torr, the pressure on the sample chamber side of the Be window could be lowered to 10 Torr. In the conventional example, 100 slits and four rotary pumps were required to set the pressure on the sample chamber side of the Be window to 10 Torr.

FIG. 3 is a diagram showing essential parts of another embodiment of the present invention. This embodiment is basically the same as the first embodiment explained in FIG. ), and the tube 17 that supports the slit plate is tilted with respect to the optical axis 16 of the X-rays.

The functions and effects of this embodiment constructed in this way are similar to those of the previous embodiment.

[0015]

[Effects of the Invention] According to the present invention, by tilting the slit plate of the differential pumping system and causing turbulence in the gas flow,
The number of slit plates and the number of exhaust pumps for obtaining the necessary differential pressure can be reduced compared to the conventional method. Furthermore, since the number of slit plates is small, the distance from the light source to the sample can be shortened, the apparatus can be made smaller, and the spread of X-rays can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a slit plate in the first embodiment of the present invention.

FIG. 3 is a diagram showing main parts of a second embodiment of the present invention.

FIG. 4 is a diagram showing a conventional synchrotron radiation light generating device.

FIG. 5 is a diagram showing a conventional radiation exposure apparatus.

[Explanation of symbols]

7...Radiation 8...Be window 9...Vacuum duct 10...Differential exhaust system 11...Sample chamber 12...Mask 13...Wafer 14...Slit plate 15...Exhaust pump 16...X-ray optical axis

Claims (1)

[Claims] 1. A vacuum duct (9) for introducing radiation, a Be window (8) provided in the vacuum duct (9),
In a radiation exposure apparatus comprising a sample chamber (11) connected to the vacuum duct (9) via a differential pumping system (10) comprising a plurality of slit plates (14) and a plurality of pumps (15). , the opening (14) of the slit plate (14)
A radiation exposure apparatus characterized in that only the opening (a) is perpendicular to the optical axis (16) of X-rays, and the portion other than the opening (14a) is tilted from the plane perpendicular to the optical axis (16) of X-rays.