JP3145809B2 - X-ray exposure equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray exposure apparatus, and more particularly to an X-ray exposure apparatus using synchrotron radiation, undulator radiation, wiggler radiation, or the like.

[0002]

2. Description of the Related Art Synchrotron radiation emitted from a storage ring has a wide wavelength range extending from hard X-rays to visible light, and has a sheet shape having a large divergence angle in the horizontal direction and a small divergence angle in the vertical direction. X-ray source that emits X-rays. As an X-ray exposure apparatus using such synchrotron radiation as an X-ray source, for example, a magazine (Nucle
ar Instruments and Method
s in Physics Research A24
6, 1986, pages 658 to 667) is shown in FIG. In the figure, 1 is a trajectory of an electron beam orbiting in a storage ring, 2 is a light source point which emits X-rays having horizontal and vertical divergence angles, 3
Is a main optical axis of the X-ray optical system, 4 is a plane X-ray reflection mirror, 5 is a vacuum window made of, for example, a beryllium film, 6 is an X-ray mask, and 7 is an exposure surface.

Next, the operation of this device will be described. An X-ray optical system is constituted by a plane X-ray reflection mirror 4 for blocking hard X-rays and a vacuum window 5 made of a beryllium film or the like for blocking a long wavelength region of several tens angstroms or more. X-rays in a wavelength band near a certain 10 Å can be extracted.

[0004]

The conventional X-ray exposure apparatus is constructed as described above, and the light source points 2 of the synchrotron radiation are distributed on the orbit 1 of the electron beam, but the vacuum window 5 Due to the restriction of the aperture of the X-ray optical system determined by the size of the electron beam, only a small number of X-rays from the light source points on the trajectory 1 of the electron beam can be extracted on the exposure surface 7.
In particular, when synchrotron radiation from a small storage ring for a semiconductor device is used, the intensity of the synchrotron radiation is not so strong, so that the X-ray intensity on the exposure surface 7 cannot be sufficiently increased. was there.

Further, the radiation divergence angle of the synchrotron radiation light is preserved as it is and irradiated onto the exposure surface 7. For this reason, the further away from the origin of the exposure surface defined by the intersection of the main optical axis 3 of the X-ray optical system and the exposure surface 7, the more X
The incidence of the line on the exposure surface 7 greatly deviates from the direct incidence.
Therefore, the transfer pattern formed on the exposure surface 7 has a problem that the positional deviation from the X-ray mask pattern increases as the distance from the origin of the exposure surface 7 increases.

The present invention has been made to solve such a problem. For example, synchrotron radiation emitted from a light source point distributed on the trajectory of an electron beam with a divergence angle in the horizontal and vertical directions is provided. By effectively condensing, the X-ray intensity on the exposed surface can be sufficiently increased,
It is still another object of the present invention to provide an X-ray exposure apparatus having an X-ray optical system capable of irradiating X-rays in a state close to direct incidence over an exposure region.

[0007]

According to an X-ray exposure apparatus according to the present invention, a light source point which emits X-rays at an angle of divergence in a horizontal direction and a vertical direction by an electron beam circulating around a storage ring is formed by an electron beam. An X-ray source distributed on an orbit, and a plurality of thin tubes having a function of bending X-rays by reflection on the inner wall surface of a thin tube bent with an appropriate curvature so as to capture X-rays radiated from the light source point. Each of the thin tubes has a bundle of thin tubes arranged so that an X-ray incident end thereof is along a trajectory of the electron beam and an X-ray emitting end is parallel to a main optical axis of the X-ray optical system.

According to another aspect of the present invention, there is provided an X-ray exposure apparatus in which a large number of magnetic poles are periodically arranged on a linear portion in a storage ring around which an electron beam circulates, and the electron beam is irradiated in a periodic magnetic field. An X-ray source for obtaining undulator light or wiggler light having a small radiation angle spread by meandering, and a plurality of thin tubes having an action of bending X-rays by reflection on the inner wall surface of the thin tube bent with an appropriate curvature are used as the X-ray source. The X-ray incidence end of each of the thin tubes follows the orbit of the electron beam meandering in the periodic magnetic field and the X-ray emission end is X-ray optics so that X-rays emitted from the source can be captured. The apparatus is provided with a bundle of thin tubes arranged parallel to the main optical axis of the system and arranged so that the X-rays emitted from each of the thin tubes cover the entire X-ray exposure area.

[0009]

In the X-ray exposure apparatus according to the present invention, the X-ray source assumes that a point light source whose light source size of the synchrotron radiation light is equal to a sufficiently small electron beam size orbiting the storage ring is distributed on the electron beam orbit. be able to. On the other hand, X-rays incident on a thin tube bent with an appropriate curvature repeatedly reflect at a very small oblique incidence angle on the inner wall surface, and bend along the curvature of the thin tube without attenuating the X-ray intensity too much. Therefore, by arranging the bundle of thin tubes appropriately so that the X-ray incident end of the thin tube follows the vicinity of the electron beam trajectory, the electron beam is independent of the size of the aperture of the X-ray optical system. All the X-rays radiated from the light source points distributed on the orbit can be taken into the thin tubes in the thin tube bundle, and the end where the X-rays are emitted from each thin tube is parallel to the main optical axis of the X-ray optical system. By appropriately bending each tubule, X exiting each tubule in the tubule bundle
The rays are collimated in parallel to the main optical axis of the X-ray optical system, and the X-rays passing through the vacuum window enter the exposure area in a state almost directly incident.

In the X-ray exposure apparatus according to another aspect of the present invention, the undulator radiation or the wiggler radiation having a larger intensity than that of the synchrotron radiation, but having a smaller radiation angle spread, is emitted from the meandering electron beam orbit. It is possible to effectively capture the X-rays, expand the irradiation area of the X-rays over the entire X-ray exposure area, and provide the X-ray exposure surface with exposure X-rays as close as possible to direct incidence.

[0011]

【Example】

Embodiment 1 FIG. FIG. 1 is a block diagram showing an X-ray exposure apparatus according to an embodiment of the present invention. In the figure, 1 is a trajectory of an electron beam orbiting in a storage ring, 2 is a light source point that emits X-rays having horizontal and vertical divergence angles,
3 is a main optical axis of the X-ray optical system, 4 is a plane X-ray reflection mirror, 5
Is a vacuum window made of, for example, a beryllium film, 6 is an X-ray mask, 7 is an exposure surface, and 8 is a thin tube which bends at an appropriate curvature and has a function of bending X-rays by reflection on an inner wall surface. The X-ray incidence end of each thin tube 8 is arranged along the vicinity of the electron beam orbit 1 and the X-ray emission end is arranged parallel to the main optical axis 3 of the X-ray optical system. All the X-rays radiated from the light source points 2 distributed to the narrow tube 8 can be taken into the thin tube 8.

FIG. 2 is an enlarged sectional view of a part of the thin tube 8 shown in FIG. 1 which is bent with an appropriate curvature. In the figure, 9 is an X-ray incident on the capillary, and θ _K is an X-ray.
The oblique incidence angle when the line 9 reflects off the inner wall surface of the capillary, R is the radius of curvature of the appropriately bent capillary, and d is the inner diameter of the capillary. When the shape of the thin tube satisfies the condition given by Equation 1, the X-rays 9 incident into the thin tube are turned into a bent thin tube 8 as shown in FIG.
Reflection is repeated along the curvature of. R> d / θ _K ² (Equation 1)

FIG. 3 is a cross-sectional view of the X-ray exposure apparatus of FIG. 1 as viewed from above including the main optical axis 3 of the X-ray optical system. FIG. 4 is a view of the X-ray optical system of the X-ray exposure apparatus of FIG. FIG. 3 is a longitudinal sectional view including a main optical axis 3. As shown in FIGS. 3 and 4, the thin tubes 8 are bent so that the ends of the thin tubes 8 from which the X-rays are emitted are parallel to the main optical axis 3 of the X-ray optical system. To X
Collimation can be performed in parallel to the main optical axis 3 of the line optical system.

The X-rays reflected m times from the inner wall surface of the thin tube 8 have an angle θ given by equation 2 from the direction of incidence on the thin tube 8.
Bend up to. θ = m × θ _K (Equation 2)

FIG. 5 shows that the X-rays incident on a thin tube made of, for example, quartz (SiO ₂ ) are obliquely incident at θ _K ;
3 shows the reflectivity of X-rays when the reflection on the inner wall surface is repeated 10 times. As shown in this figure, since the reflectivity in the hard X-ray region of 5 Å or less, which is not suitable for X-ray exposure, is high, the X-ray reflection arranged at an appropriate position in the X-ray optical system as shown in FIG. The mirror 4 can block hard X-rays. The X-ray reflecting mirror 4 is not required when it is desired to use hard X-rays of 5 Å or less.

In the X-ray exposure apparatus configured as described above, the X-ray source is a synchrotron radiation light in which a point light source equal to a sufficiently small electron beam size orbiting the storage ring is distributed on the electron beam orbit. Can be considered. On the other hand, X-rays incident on a thin tube bent with an appropriate curvature repeatedly reflect at a very small oblique incidence angle on the inner wall surface, and bend along the curvature of the thin tube without attenuating the X-ray intensity too much. Therefore, by appropriately arranging the bundle of thin tubes such that the end of each thin tube where the X-rays are incident is along the vicinity of the electron beam trajectory, regardless of the size of the aperture of the X-ray optics, All the X-rays radiated from the light source points distributed on the beam trajectory can be taken into the thin tubes in the thin tube bundle, and the end where the X-rays are emitted from each thin tube of the thin tube bundle is parallel to the main optical axis of the X-ray optical system. The X-rays exiting from each of the thin tubes of the thin tube bundle are collimated parallel to the main optical axis of the X-ray optical system by appropriately bending each thin tube so that Further, the hard X-rays are blocked by an X-ray reflecting mirror disposed at an appropriate position in the X-ray optical system, and the X-rays passing through the vacuum window enter the exposure area in a state as close as possible to direct incidence, and have extremely high intensity. It becomes an exposure X-ray.

Embodiment 2 FIG. FIG. 6 is an explanatory diagram of undulator radiation and wiggler radiation according to the second aspect of the present invention. In the figure, 19 is a beam duct of a straight part of the storage ring, 10 is a periodic arrangement of a number of magnetic poles for generating a periodic magnetic field in the beam duct 19, 11
Denotes an orbit of an electron beam meandering in a periodic magnetic field, and 12 denotes undulator radiation or wiggler radiation emitted from the meandering electron beam orbit 11.

When a periodic magnetic field as shown in Expression 3 is generated in the beam duct 19 by the periodic magnetic pole arrangement 10, the electron beam orbit 11 meanders and becomes a sinusoidal orbit having the same period length as the magnetic field. Become. B _y = B ₀ × sin (2πz / λ _u ) (Equation 3)
In Equation 3, λ _u is the period length of the periodic magnetic field. At this time, when K is a parameter defined by Expression 4, when K ≦ 1, the ordinary synchrotron radiation shown in Example 1 has a conical angular spread around the Z axis of the center axis of the electron beam orbit. Undulator light having a greater intensity than light is emitted. K = 93.4 × B ₀ (tesla) × λ _u (m) (Equation 4) When K ≧, wiggler light having a larger emission angle spread than the above undulator light is emitted.

FIG. 7 shows X according to an embodiment of the present invention.
FIG. 2 is a configuration diagram illustrating a line exposure apparatus. The X-ray incident end of each thin tube 8 extends along the meandering electron beam orbit 11 and the X-ray emitting end is parallel to the main optical axis 3 of the X-ray optical system. By arranging the thin tube bundle so that the X-rays cover the entire X-ray exposure area, the radiation angle spread emitted from the meandering electron beam orbit 11 is small, but the intensity is high, and the undulator light or wiggler light 12 is effectively taken in. The irradiation area of X-rays can be widened over the entire X-ray exposure area, and exposure X-rays as close as possible to direct incidence can be provided on the X-ray exposure surface.

[0020]

As described above, according to the present invention, a light source point that emits X-rays at an angle of divergence in the horizontal and vertical directions by an electron beam circling the storage ring is positioned on the trajectory of the electron beam. X-ray sources that are distributed and a plurality of thin tubes having a function of bending X-rays by reflecting on the inner wall surface of the thin tube bent with an appropriate curvature so as to capture X-rays emitted from the light source point. X
X-ray incident end along the electron beam trajectory and X
Equipped with a bundle of thin tubes arranged so that the radiation exit end is parallel to the main optical axis of the X-ray optical system, so that synchrotron radiation emitted from the light source point with a divergence angle in the horizontal and vertical directions is effective. The X-ray intensity on the exposure surface can be sufficiently increased by condensing the X-rays on the exposure surface.
This has a great effect on the throughput in line exposure and a highly accurate transfer pattern.

According to another aspect of the present invention, a large number of magnetic poles are periodically arranged in a linear portion in a storage ring around which an electron beam circulates, and the electron beam meanders in a periodic magnetic field. An X-ray source for obtaining undulator light or wiggler light having a small emission angle spread, and a plurality of thin tubes having an action of bending X-rays by reflection on the inner wall surface of a thin tube bent with an appropriate curvature are radiated from the X-ray source. The X-ray entrance end of each of the thin tubes follows the orbit of the electron beam meandering in the periodic magnetic field, and the X-ray exit end is the main light of the X-ray optical system so that X-rays can be captured. Since a bundle of thin tubes arranged parallel to the axis and arranged so that the X-rays emitted from each of the thin tubes cover the entire X-ray exposure area is provided, in addition to the above-described effects, X-rays with higher intensity can be obtained. There is that effect.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an X-ray exposure apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a part of the thin tube shown in FIG.

FIG. 3 is a top view including a main optical axis of an X-ray focusing optical system of the X-ray exposure apparatus shown in FIG.

4 is a longitudinal sectional view including a main optical axis of an X-ray focusing optical system of the X-ray exposure apparatus shown in FIG.

FIG. 5 is a characteristic diagram showing a relationship between wavelength and reflectance when X-rays incident on a thin tube made of quartz (SiO ₂ ) are repeatedly reflected ten times.

FIG. 6 is an explanatory diagram of undulator radiation and wiggler radiation.

FIG. 7 is a block diagram showing an X-ray exposure apparatus according to an embodiment of the present invention.

FIG. 8 is a configuration diagram showing a conventional X-ray exposure apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Orbit of electron beam 2 Light source point 3 Main optical axis of X-ray optical system 4 X-ray reflection mirror 5 Vacuum window 6 X-ray mask 7 Exposure surface 8 Thin tube 9 X-rays incident into thin tube 11 Orbit of meandering electron beam 12 Undulator radiation or wiggler radiation

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/027

Claims (2)

(57) [Claims] 1. A light source point that emits X-rays at an angle of divergence in the horizontal and vertical directions by an electron beam orbiting a storage ring is distributed on the orbit of the electron beam.
An X-ray of each of the thin tubes so that the X-rays radiated from the light source point can be captured by a plurality of thin tubes having a function of bending the X-rays by reflection at the inner wall surface of the thin tube bent with an appropriate curvature. An X-ray exposure apparatus comprising: a bundle of thin tubes arranged so that an incident end thereof is along the vicinity of the trajectory of the electron beam and an X-ray emitting end is parallel to a main optical axis of the X-ray optical system. 2. An undulator light beam having a small radiation angle spread by periodically arranging a large number of magnetic poles in a linear portion in a storage ring around which an electron beam circulates and meandering the electron beam in a periodic magnetic field. An X-ray source for obtaining wiggler light, and a plurality of thin tubes having an action of bending X-rays by reflection on the inner wall surface of a thin tube bent with an appropriate curvature so as to capture X-rays emitted from the X-ray source. The X-ray incident end of each of the thin tubes follows the vicinity of the trajectory of the electron beam meandering in the periodic magnetic field, and the X-ray emitting end is parallel to the main optical axis of the X-ray optical system. An X-ray exposure apparatus, comprising: a bundle of thin tubes arranged so that X-rays radiated from the tube cover the entire X-ray exposure area.