JP2002139758A - Device for shortening light wavelength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for shortening light wavelength in which the variation of wavelength of light does not occur even if energy of an electron beam from an electron beam source is varied, or/also, a shortened wavelength of light can be easily changed. SOLUTION: This device is provided with an electron beam source 10, a laser beam source 20, and a vacuum chamber 30, electrons in an electron beam which are emitted from the electron beam source 10 and moving at relativistic speed is collided with photons in a laser beam emitted from the laser beam source 20 in the vacuum chamber 30, energy of electrons is given to photons of the laser beam. A device for shortening light wavelength to shorten scattered light wavelength is provided with angle varying means 21, 22 for changing a collision angle of the laser beam and the electron beam before collision of electrons and photons, in order to change wavelength of scattered light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wavelength shortening apparatus using so-called inverse Compton scattering or laser Compton scattering.

[0002]

2. Description of the Related Art The design rule of a semiconductor device is steadily miniaturized.
25 μm rule, 0 .0 in 1 Gbit DRAM.
In the case of the 18 μm rule and a 4 Gbit DRAM, the memory capacity is set to 0.
It is expected that the rule will be 13 μm. As the design rule becomes finer, the light source in the so-called lithography technique has become one of the major problems.

That is, in a semiconductor exposure apparatus used for manufacturing a semiconductor device, when the wavelength of exposure light used for exposing (photosensitizing) a resist material is λ and the numerical aperture of a lens is NA, the resolution is Rayleigh. Equation of kλ / NA
Is represented by Here, k is a constant. It is clear from this Rayleigh equation that as the design rule becomes smaller, a sufficient resolution cannot be obtained unless an exposure light source having a short wavelength λ is used. Therefore, ~ 0.15μ
In the m rule, a KrF excimer laser (λ = 248
nm), Ar in the 0.13-0.10 μm rule
It is said that it is necessary to use an F excimer laser (λ = 193 nm).

With the miniaturization of such design rules, lithography technology using an electron beam and lithography technology using an X-ray beam using synchrotron radiation are being studied in order to obtain exposure light of a short wavelength. .
However, lithography technology using electron beams
Although it is suitable for the manufacture of various types of semiconductor devices in small quantities, it has low throughput and is not suitable for mass production of semiconductor devices. Further, the lithography technique using an X-ray beam to which synchrotron radiation is applied has a problem that a large-scale and complicated apparatus is required as an X-ray source, and an increase in manufacturing cost of a semiconductor device is unavoidable. Therefore, if lithography technology using light (laser), which is an extension of the conventional technology, can cope with miniaturization of the design rule of a semiconductor device, such technology can be said to be the most preferable technology. However, it is very difficult to develop a new laser having a desired wavelength in response to a change in design rules, and it is necessary to shorten the wavelength of exposure light and develop a laser together. It can be said that development efficiency is poor.

The Compton scattering phenomenon, which includes X-rays scattered by a substance whose wavelength is shifted to a longer wavelength than the wavelength of incident X-rays, has been known for a long time. In such Compton scattering, X-rays impinge on stationary electrons and are scattered. The electrons receive the energy of the X-rays and the energy of the X-rays themselves decreases.
On the other hand, the inverse Compton effect, in which the energy of electrons is given to photons by the scattering of light by electrons moving at a relativistic velocity and the wavelength of the scattered light is shortened, has been known for a long time. For example, E. Feenberg and H. Primakoff, Phys.
Rev. 73, (1948) 449 or RH Milburn, Phys. R
ev. Lett. 10 (1963) 75 and FR Arutyunian and VA
Tumanian, Phys. Lett. 4 (1963) 176, "Generation of energy-variable polarized monochromatic γ-rays-application of inverse Compton scattering",
Hideaki Ogaki and Tsutomu Noguchi, Journal of the Physical Society of Japan, Vol.50, N
o.5 (1995) See pp381-386.

[0006] Also, the magazine "Parity" Vol.12, No.01, 1
According to the News Digest on page 47 of 997-01, Shaneline et al.'S team at the Lawrence Berkeley National Laboratory's Materials Science Division converted infrared laser pulses into an electron beam extracted from a linear accelerator. It is reported that an extremely short X-ray pulse of sub-picosecond scattered in the direction of the electron beam was observed at right angles. That is, in the experiment of Shaneline et al., A laser pulse of the terawatt class was focused on a spot having a diameter of 30 μm with a mirror having a radius of curvature of 75 cm, and the energy extracted from the linear accelerator was 50 MeV.
The beam is applied at right angles to an electron beam having a beam thickness of about 90 μm. As a result, it is reported that an X-ray pulse with good directivity of 30 eV (wavelength 0.04 nm) and pulse of 0.3 psec was observed in the direction of the electron beam. The X-ray intensity is about 5 × 10 ⁴ per pulse in terms of the number of photons. Further, in 1995, the Navy Research Institute
It is reported that a V electron beam and a laser beam having an output of 1 TW collide head-on, and radiation having an energy of 20 eV was obtained as back scattering of the laser beam.

[0007]

The techniques disclosed in these documents relate exclusively to the study of the structure of the nucleus and to the study of chemical reactions, phase transitions and surface processes.
It is possible to conduct research with sufficient line strength. Further, according to these documents, a large-scale device is required as an electron beam source. However, in the lithography process, it is required that the apparatus be as simple as possible.
In addition, when there is a variation in the energy of the electron beam from the electron beam source, such variation appears as a variation in the wavelength of the light whose wavelength has been shortened.

A technique using a laser-induced plasma X-ray source, which uses X-rays generated in the process of cooling the metal plasma and recombination of highly excited ions, as a light source for X-ray reduction exposure is disclosed in K. Tanaka, et al. , "Laser plasma X-ray source
and its application to lithograph ", SPIE, vol. 114
0, pp. 350, 1898. In this laser-induced plasma X-ray source, it is necessary to frequently maintain the laser-induced plasma X-ray source because cooled metal ions or metal particles adhere to optical elements, detectors, and the like. As a means for solving such a problem, a method using an inert gas frozen and solidified target instead of a metal target is known as GD Kubiak, KD Kr.
enz and KW Berger, "Cryogence Pallet Laser Plasm
a Source Target ", OSA, Proc. on EUVL, vol. 23 (199
4), pp. 248-254. However, this method requires that the target be frozen to cryogenic temperatures. Further, in these methods, since the wavelength of the generated X-ray source depends on the type of the target, there is a problem that the target needs to be replaced when the wavelength is changed.

Japanese Patent Application Laid-Open No. 10-290053 or Japanese Patent Application Laid-Open No. 10-326928 has an electron beam source, a laser light source, and a vacuum chamber, and moves at a relativistic speed emitted from the electron beam source. Shortening the wavelength of light by colliding electrons in the electron beam with photons in the laser beam emitted from the laser light source in a vacuum chamber, giving the energy of the electrons to the photons of the laser beam, and shortening the wavelength of scattered light. Although an apparatus is disclosed, even in the optical wavelength shortening apparatus disclosed in these patent publications, when there is a fluctuation in the energy of the electron beam from the electron beam source, such fluctuation is shortened. There is a problem that the change appears as a change in the wavelength of light, or it is difficult to easily change the wavelength of light whose wavelength has been shortened.

Therefore, an object of the present invention is that even if the energy of the electron beam from the electron beam source fluctuates, such fluctuation does not appear as a fluctuation in the wavelength of the light whose wavelength has been shortened, or The present invention provides an optical wavelength shortening device that can easily change the wavelength of light whose wavelength has been shortened and can easily obtain an electromagnetic wave (ultraviolet ray, soft X-ray, or the like) having a desired wavelength. Is to do.

[0011]

According to a first aspect of the present invention, there is provided an optical wavelength shortening apparatus comprising an electron beam source, a laser light source, and a vacuum chamber. The electrons in the electron beam moving at the relativistic velocity collide with the photons in the laser beam emitted from the laser light source in a vacuum chamber, and the energy of the electrons is given to the photons of the laser beam and scattered. An optical wavelength shortening device for shortening light, wherein an angle change is performed to change a collision angle between a laser beam and an electron beam before a collision between an electron and a photon in order to change a wavelength of scattered light. Means is provided.

The energy of the electrons in the electron beam when colliding with the photons in the laser beam is E, the wavelength of the photons of the laser beam before colliding with the electrons in the electron beam is λ _L , the wavelength of the scattered light is λ, If β is [electron speed / light speed], photon scattering angle is θ, collision angle between electron beam and laser beam is θ _L , and h is Planck constant, inverse Compton scattering considering relativistic effect Alternatively, based on the law of conservation of energy and the law of conservation of momentum in laser Compton scattering, the wavelength λ of the scattered light is given by the following equation (1).

[Equation 1] λ = [λ _L (1−β cos θ) + (hc / E) {1−cos (θ _L −θ)}] / (1−β cos θ _L ) (1)

As is apparent from the equation (1), when the energy E of the electrons in the electron beam when colliding with the photons in the laser beam fluctuates (in other words, the electrons in the electron beam emitted from the electron beam source change). Of the scattered light varies). Since the optical wavelength shortening device according to the first aspect of the present invention includes the angle changing means, even if such a change in the electron energy E occurs, the scattered light (ultraviolet light or soft X-ray Etc.) can be kept constant. Note that the collision angle θ _L between the electron beam and the laser beam is as long as the desired λ of the scattered light is obtained, as long as the expression (1) is satisfied.
Any angle can be used.

The length L of the collision area where the electron and the photon collide with each other is as follows: when the larger of the electron beam diameter and the laser beam diameter is D, 0 <θ _L <π; = 1
/ Sin θ _L. The yield of shortened photons is D
And inversely proportional to L. Therefore, the value of θ _L is π
(= 180 degrees) is preferable from the viewpoint of improving the yield of photons having a shorter wavelength. That is, it is preferable to configure the system so that the incident electron beam and the laser beam collide substantially from the front, so-called head-on collision.

Alternatively, for example, when the optical wavelength shortening device according to the first aspect of the present invention is used as a light source (energy source) in a lithography process in the manufacture of a semiconductor device, depending on the specifications of the semiconductor device, the light source may be changed from a light source. It may be necessary to change the wavelength of the emitted light. Specifically, for example, in the manufacture of a semiconductor device, it may be necessary to perform exposure of a certain layer using a light source having a shorter wavelength than that of another layer. In such a case, the optical wavelength shortening device according to the first aspect of the present invention easily includes scattered light (such as ultraviolet light and soft X-ray) having a desired wavelength because the device has an angle changing means. Can be obtained.

In the optical wavelength shortening apparatus according to the first aspect of the present invention, the angle changing means includes a reflecting mirror and a reflecting mirror angle changing means disposed in a vacuum chamber, and the reflecting mirror is an electronic device. Between the laser light source and the collision region where the laser beam and the photon collide with each other, so as not to collide with the electron beam incident on the collision region. In this case, a configuration may be adopted in which a second reflecting mirror disposed so as not to collide with the scattered light emitted from the collision area is further provided in the vacuum chamber. The half mirror angle (1 / γ) having the collision area as the apex (where γ is the Lorentz factor corresponding to the energy of the electrons after the collision) has a reflecting mirror or a second mirror outside the conical space. It is preferable that a reflecting mirror (hereinafter, sometimes referred to as a reflecting mirror or the like) is provided. The Lorentz factor means a factor [γ = (1−β ² ) ^−1/2 ] that appears in the Lorentz transformation factor of the special relativity. If desired, third, fourth,... Reflecting mirrors may be further provided. By arranging the reflecting mirror and the like in this manner, it is possible to reliably prevent damage to the reflecting mirror and the like,
Moreover, it is possible to reliably prevent the loss of the electron beam or the scattered light due to the collision of the electron beam or the scattered light with these reflecting mirrors. Note that the position and shape of the electron beam in the vacuum chamber can be monitored using a beam monitor (Desmarqu
est, composed of alumina containing chromium oxide)
, And a reflecting mirror or the like may be arranged at an optimal position in the vacuum chamber. In some cases, the reflecting mirror and / or the second reflecting mirror may be provided outside the vacuum chamber.

As the reflecting mirror angle changing means, there is exemplified a combination of an actuator made of, for example, a piezoelectric element, or a pedestal on which a reflecting mirror or the like is mounted and which can rotate, and a rotating mechanism (for example, a stepping motor). Can be. Specifically, for example, an actuator composed of a piezoelectric element or the like is attached to the back surface of a reflecting mirror or the like, and the actuator is controlled, or the reflecting mirror or the like is mounted on a rotatable pedestal. By rotating the stepping motor, the collision angle θ _L between the laser beam and the electron beam can be easily changed.

Alternatively, in the optical wavelength shortening apparatus according to the first aspect of the present invention, the angle changing means includes an electromagnet, and the electromagnet includes a collision region where electrons and photons collide, and an electron beam source. The configuration may be provided between them. In addition, such an electromagnet may be provided outside the vacuum chamber or may be provided inside. The number of electromagnets may be a number that can appropriately change the trajectory of the electron beam, and may be one or more. By controlling the strength of the magnetic field formed by the electromagnet, the electron beam can be deflected. As a result, the collision angle θ _L between the laser beam and the electron beam can be easily changed.

In the optical wavelength shortening apparatus according to the first aspect of the present invention, the energy (E) of the electron beam emitted from the electron beam source is preferably 1 × 10 ⁷ eV (10 MeV) or less. By setting the energy (E) of the electron beam to such an upper limit, the size of the electron beam source to be used can be reduced, and a scattered light wavelength (λ) within a practical wavelength range can be obtained. Can be. In this case, the energy (E) of the electron beam emitted from the electron beam source is preferably 1 × 10 ⁵ eV (0.1 MeV) or more. When the energy (E) of the electron beam emitted from the electron beam source is less than 1 × 10 ⁵ eV, the effect of shortening the wavelength of light by inverse Compton scattering is small, and moreover, the scattering between electrons in the electron beam causes electrons to be generated. It may be difficult to narrow the beam to the desired size.

In the optical wavelength shortening apparatus according to the first aspect of the present invention, the electron beam and the laser beam may collide with each other a plurality of times in the collision area, if desired. In this case, the collision area is at least partially partitioned by a highly reflective surface, or a reflecting portion is provided on the end face of the optical waveguide or the optical waveguide is connected in a ring shape to confine the light wave three-dimensionally. It is preferable to use an optical resonator as a device, and a pair of parallel plane mirrors represented by a Fabry-Perot resonator, a pair of concave mirrors facing each other (for example, a confocal Fabry-Perot resonator), a combination of a concave mirror and a plane mirror, A ring resonator including one or more reflecting mirrors can be exemplified. In an optical resonator constituted by a pair of opposed concave mirrors, it is preferable that a laser beam and an electron beam collide in a beam waist region.

The second object of the present invention for achieving the above object.
The optical wavelength shortening device according to the aspect includes an electron beam source, a laser light source, and a vacuum chamber, and the electrons in the electron beam moving at a relativistic speed emitted from the electron beam source and emitted from the laser light source. A light wavelength shortening device that collides photons in a laser beam in a vacuum chamber to apply energy of electrons to photons of the laser beam, thereby shortening the wavelength of scattered light, and is emitted from an electron beam source. The electron beam has an energy of 1 × 10 ⁷ eV (10 MeV) or less.

In the optical wavelength shortening apparatus according to the second aspect of the present invention, the size of the electron beam source used can be reduced by setting the energy of the electron beam to such an upper limit. It is possible to obtain a scattered light wavelength within a practical wavelength range. In this case, the energy of the electron beam emitted from the electron beam source is 1 × 10 ⁵ e.
It is preferably at least V.

In the optical wavelength shortening device according to the first or second aspect of the present invention (hereinafter, sometimes simply referred to as the optical wavelength shortening device of the present invention), the collimated electron beam is used. Where A (unit: cm ² ) is the larger cross-sectional area of the laser beam and the cross-sectional area of the laser beam, 1 × 10 ⁻⁶ ≦ A ≦ 1
It is preferable to satisfy × 10 ⁻¹ . Here, which one of the cross-sectional area of the colliding electron beam and the cross-sectional area of the laser beam becomes larger is determined by the design of the optical wavelength shortening device.

In the optical wavelength shortening device of the present invention, the electron beam source may be constituted by an electron linear accelerator and a focusing lens system. However, from the viewpoint of miniaturization and simplification of the device, the electron gun and the buncher are used. It is preferable to form a focusing lens system (electromagnetic lens system such as a quadrupole magnet). Here, the buncher is a device for bunching electrons. Note that a pre-buncher may be provided between the electron gun and the buncher. Alternatively, for example, an electron beam source similar to an electron beam source in a transmission electron microscope can be applied. That is, the electron beam source may be constituted by an electron gun and a focusing lens system (an electromagnetic lens system such as a quadrupole magnet). Alternatively, when electrons emitted by photoelectron emission by a laser or the like have already been bunched, the electron beam can be directly accelerated by a high frequency or an electrostatic field. As an electron gun, for example, a hot cathode of a hairpin type tungsten wire (or a point cathode type hot cathode or a lanthanum hexaboride LaB ₆ hot cathode)
And a thermionic electron gun composed of a Wehnelt electrode and a ground potential anode. Alternatively, a field emission type electron gun including a cathode chip, a first anode (extraction electrode), and a second anode can be used. Further, a Schottky emission type electron gun can be used. As an electron linear accelerator (Linac),
A traveling wave type linear accelerator, a standing wave type linear accelerator, an induction type linear accelerator, a high voltage rectifier type accelerator (for example, a Cockcroft-Walton type accelerator), a bandeograph type accelerator, a resonance transformer type accelerator, or the like can be used. The traveling wave type linear accelerator may be a disk-loaded waveguide type, and the standing wave type linear accelerator may be an Alvaret type, a general cavity type, or a high frequency quadrupole type. Further, the electron linear accelerator may be provided with a buncher.

As the laser light source, a continuous wave laser light source can be used. However, it is desirable to use a Q-switch laser capable of emitting a laser with high efficiency and high output and a short pulse width. Examples thereof include a solid-state laser such as an Nd: YAG laser and a titanium sapphire laser, a gas laser such as a carbon dioxide laser, a XeCl excimer laser, a KrF excimer laser, and an ArF excimer laser. As the laser light source, the output (P) is 0.1
mJ / cm ² or more, and the wavelength is, for example, 10
0 nm or more, the beam diameter (d) is 1 mm or less, and the repetition frequency (f) is high, that is, P
It is preferable to use a laser light source having a large value of f / d.

In the optical wavelength shortening apparatus of the present invention,
If the energy of the electron beam emitted from the electron beam source is set to 1 × 10 ⁷ eV or less, it is not necessary to consider the shielding of neutrons with thick concrete, polyethylene, or water. It is only necessary to cover the optical wavelength shortening device with a radiation shielding material made of a high-density and inexpensive substance, for example, iron, lead, or the like, and the structure of the optical wavelength shortening device can be simplified. More specifically, from the tangent extension of the trajectory of the electron beam incident on the vacuum chamber,
It is desirable to dispose the radiation shielding material such that at least the radiation shielding material covers a region of the optical wavelength shortening device located on a tangent extension of the trajectory of the electron beam emitted from the vacuum chamber. Further, in order to separate the electron beam emitted from the vacuum chamber from the scattered light having a reduced wavelength, the electron beam deflecting means (more specifically, for example,
An electromagnet) is provided, and the electron beam deflected by the electron beam deflecting means is made to collide with an electron beam damper (for example, an iron plate or a lead plate provided with a Faraday cup or a radiation fin, or a water tank). Preferably, the energy of the electrons in the beam is lost, for example, as heat. In this case, it is desirable to further provide a radiation shielding material so as to cover the electron beam damper.
In addition, all or a part of the radiation shielding material may also serve as a structural material of the optical wavelength shortening device, or may also serve as an anti-vibration base of the optical wavelength shortening device or the exposure device. Generally, when the energy of an electron beam emitted from an electron beam source is 1 × 10 ⁷ eV or less, most of the generated radiation is gamma rays, and most of the gamma rays are emitted based on bremsstrahlung radiation. You. That is, when an electron having high energy enters a substance and passes near a nucleus, the traveling direction of the electron is sharply bent by the Coulomb force of the nucleus, and the electron emits γ-rays in a tangential direction, and the electrons are emitted. Lose energy. Since the electron has a small mass, its traveling direction is easily bent and γ rays are easily emitted.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments of the invention with reference to the drawings.

(Embodiment 1) Embodiment 1 relates to an optical wavelength shortening apparatus according to the first and second aspects of the present invention. FIG. 1 shows a conceptual diagram (conceptual plan view) of the optical wavelength shortening device according to the first embodiment. This optical wavelength shortening device comprises an electron beam source 10, a laser light source 20, a vacuum chamber 3
0. The electron beam source 10 includes a thermionic emission type electron gun 11, a pre-buncher and buncher 13, and a focusing lens system 14. Note that a pulsed electron beam [energy E is 1 ×
10 ⁵ eV (0.1 MeV) to 1 × 10 ⁷ eV (10 M
eV)]. It should be noted that such a low energy electron beam can be obtained only by the pre-buncher and the buncher 13 without using a large-sized device such as an electron linear accelerator (linac).
The laser light source 20 is a Q-switched laser, for example, an Nd: YAG laser (wavelength λ _L : 1064 nm). The vacuum chamber 30 is provided with a window through which a laser beam is incident and a window through which the laser beam is emitted, but these windows are not shown. A current monitor (also called a core monitor) 12 is arranged between the electron gun 11 and the pre-buncher and buncher 13, and a klystron 15, also called a speed modulator, is attached to the pre-buncher and buncher 13. A detector 16 is attached to 15. Here, the inside of the vacuum chamber 30 and a passage (not shown) through which the electron beam passes are 10 ^−5.
The degree of vacuum is maintained at about Pa to 10 ^-6 Pa. still,
The length from the electron gun 11 to the focusing lens system 14 is about 2 m, and the entire optical wavelength shortening apparatus can be accommodated in a space of several meters square at most.

The optical wavelength shortening apparatus further includes an angle changing means for changing the collision angle between the laser beam and the electron beam before the collision between the electron and the photon in order to change the wavelength of the scattered light. Have. This angle changing means is, specifically, a reflecting mirror 21 provided in the vacuum chamber 30.
And reflecting mirror angle changing means (specifically, the actuator 22). The reflecting mirror 21 may collide with an electron beam incident on the collision region between the collision region 24 (indicated by a circled region in the figure) where the electron and the photon collide with the laser light source 20. It is not arranged. The optical wavelength shortening device of the first embodiment further includes a second reflecting mirror 23 disposed so as not to collide with the scattered light emitted from the collision area 24. Depending on the structure of the optical wavelength shortening device, the second reflecting mirror 23 is unnecessary. Here, the reflecting mirror 21 and the second reflecting mirror 23
Half vertex angle (1 / γ) with the collision area 24 as the vertex [where,
γ is disposed outside a conical space having a Lorentz factor corresponding to the energy of electrons after collision.

The laser beam emitted from the laser light source 20 passes through a well-known lens system (not shown), enters the vacuum chamber 30, and includes the reflecting mirror 21 and the second reflecting mirror 23.
Through the laser beam damper 41 provided outside the vacuum chamber 30 through the laser beam damper 4.
1 loses its energy. On the other hand, the electron beam emitted from the focusing lens system 14 of the electron beam source 10 enters the vacuum chamber 30 while moving at a relativistic speed.
Then, electrons in the electron beam and photons in the laser beam emitted from the laser light source 20 collide in the vacuum chamber 30. Specifically, the laser beam reflected by the reflecting mirror 21 and the electron beam collide. As a result, the energy of the electrons is given to the photons of the laser beam, and the wavelength of the scattered light is shortened based on inverse Compton scattering or laser Compton scattering. After the collision,
The electron beam is emitted from the vacuum chamber 30 and is arranged on the trajectory of the electron beam emitted from the vacuum chamber in order to separate the electron beam emitted from the vacuum chamber from the scattered light having a reduced wavelength. Deflection means 4
2 (more specifically, for example, an electromagnet), collides with the electron beam damper 43, and loses the energy of the electrons in the electron beam as heat. here,
Since the momentum of photons in the laser beam incident on the vacuum chamber 30 is much smaller than the momentum of electrons on the electron beam incident on the vacuum chamber 30, the photon does not depend on the collision angle θ _L between the laser beam and the electron beam. The traveling direction of the scattered light substantially coincides with the traveling direction of the electron beam emitted from the vacuum chamber 30. The scattered light that has passed through the electron beam deflecting means 42 enters the exposure apparatus. In FIGS. 1, 4 and 5, the electron beam is indicated by a solid line, and the laser beam is indicated by a dotted line. Further, the scattered light has a certain degree of spread (a conical shape with a half apex angle (1 / γ) having the collision region 24 as an apex), but in FIG. 1, FIG. 4 and FIG. This is indicated by a dashed line.

FIG. 2 shows a conceptual diagram of an example of an exposure apparatus used in a lithography step in the manufacture of a semiconductor device. The scattered light from the light wavelength shortening device as an exposure light source includes an illumination optical system 50 for shaping the scattered light, a reflective mask 51,
After entering the semiconductor substrate 53 via the reduction optical system 52,
The resist material formed on the semiconductor substrate is exposed.
In addition, as the exposure apparatus, an exposure apparatus such as a contact exposure apparatus, a proximity exposure apparatus, and a projection exposure apparatus that projects a pattern formed on a reflective mask at the same magnification can be used. Thereby, the pattern formed on the reflective mask can be transferred to the resist material formed on the semiconductor substrate.

On the back surface of the reflecting mirror 21, an actuator 2
2 are installed. Then, based on the current value of the electron beam detected by the current monitor 12 and the high-frequency peak power detected by the detector 16, the energy E of the electron beam in the electron beam when colliding with a photon in the laser beam is determined. The fluctuation (more specifically, the fluctuation ΔE of the energy of the electrons in the electron beam emitted from the electron beam source 10) is monitored. Then, based on Δθ _L obtained from the equation (1), the actuator 22 is actuated to compensate the incident laser beam with the reflecting mirror 21 so as to compensate for the wavelength variation Δλ of the scattered light caused by ΔE. Fine-tune to the optimal angle. The actuator 22 is, for example,
It can be composed of a piezoelectric element. An actuator is also attached to the second reflecting mirror 23, and the vacuum chamber 3
Control may be performed so that the emission direction of the laser beam from 0 is constant.

In the first embodiment, when the optical wavelength shortening device is configured as described above, the collision angle θ _L between the electron beam and the laser beam can be compensated.
Even if the electron energy E fluctuates, the wavelength λ of the scattered light (ultraviolet rays, soft X-rays, etc.) can be kept constant.

In the optical wavelength shortening apparatus shown in FIG. 1, scattered light (soft X-ray) passing through the electron beam deflecting means 42 was measured by a multi-channel plate for a test.
The collision angle θ _L between the electron beam and the laser beam is set to 13
5 degrees. Also, the pulse of the laser beam is a few nanoseconds,
The pulse of the electron beam was 1 microsecond. Electron beam source 1
The energy of the electron beam emitted from 0 is 6.
It was 5 × 10 ⁶ eV (6.5 MeV). FIG. 3 shows the measurement results. In FIG. 3, the horizontal axis represents the time elapsed (0 unit) when the collision between the electron beam and the laser beam is 0 seconds (unit:
Nanoseconds), and the vertical axis represents the voltage (unit: millivolt) measured by the multi-channel plate. As is clear from FIG. 3, it is found that soft X-rays are generated immediately after the collision between the electron beam and the laser beam. According to equation (1), the wavelength of this soft X-ray (scattered light) is 1.7 n
m.

The angle changing means may be constituted by an angle changing electromagnet. In this case, as shown in a conceptual diagram (conceptual plan view) in FIG.
A collision region 24 where electrons and photons collide with each other;
And more specifically, on the trajectory of the electron beam between the focusing lens system 14 and the vacuum chamber 30. Then, based on the current value of the electron beam detected by the current monitor 12 and the high-frequency peak power detected by the detector 16, the energy E of the electron in the electron beam when colliding with a photon in the laser beam is determined.
(More specifically, a change ΔE in the energy of electrons in the electron beam emitted from the electron beam source 10) is monitored. Then, Δθ obtained from equation (1) is compensated to compensate for the variation Δλ of the wavelength of the scattered light caused by ΔE.
Based on _L , the angle changing electromagnet 25 is operated to compensate for the trajectory of the electron beam. Even with such a configuration, the collision angle θ _L between the electron beam and the laser beam can be compensated. As a result, even if the energy E of the electron fluctuates, the scattered light (ultraviolet rays, soft X-rays, etc.) Wavelength λ
Can be kept constant. Here, the value of θ _L is π
If the value is close to (= 180 degrees), the change in the trajectory of the scattered light due to the change in the trajectory of the electron beam is insignificant, and the change in the optical path to the exposure apparatus is small enough to cause no problem. Incidentally, an electromagnet for correcting the trajectory of the electron beam emitted from the vacuum chamber 30 may be further provided. Further, the optical wavelength shortening device includes an electromagnet 25 for changing the angle.
And the actuator 22. That is, the optical wavelength shortening device shown in FIG. 1 and the optical wavelength shortening device shown in FIG. 4 may be combined.

(Embodiment 2) The optical wavelength shortening device of the embodiment 2 is a modification of the optical wavelength shortening device of the embodiment 1. FIG. 5 is a conceptual diagram (conceptual plan view) of the optical wavelength shortening device according to the second embodiment. The optical wavelength shortening device according to the second embodiment differs from the optical wavelength shortening device according to the first embodiment shown in FIG. 1 in that a current monitor 12, a klystron 15, a detector 16, and an actuator 22 are arranged. Not provided and provided with angle changing means for arbitrarily changing the angle of the laser beam emitted from the reflecting mirror 21, and a movable reflecting mirror in the traveling direction of the scattered light passing through the electron beam deflecting means 42. 44 is provided. Note that the angle changing means can be composed of, for example, a pedestal 26 on which the reflecting mirror 21 is mounted, and a rotation mechanism (for example, a stepping motor (not shown)) for rotating the pedestal. With such a configuration, the collision angle θ _L between the electron beam and the laser beam can be changed to an arbitrary value. As a result, the wavelength λ of the scattered light can be changed based on Expression (1). .

Depending on the specifications of the semiconductor device, it may be necessary to change the wavelength of the light emitted from the light source.
By using the optical wavelength shortening device of the second embodiment as an exposure light source in a lithography step in the manufacture of a semiconductor device, such a demand can be easily met. More specifically, for example, when an exposure wavelength before and after an ArF excimer laser (λ = 193 nm) is required, the movable reflecting mirror 44 is moved in the traveling direction of the scattered light passing through the electron beam deflecting means 42. At least, movable mirror 4
The scattered light (for example, far ultraviolet light) reflected by 4 is incident on the first exposure apparatus. The first exposure apparatus may have a configuration other than the exposure light source, for example, similar to that of an exposure apparatus using an ArF excimer laser as an exposure light source. Specifically, an exposure apparatus using a transmission type reticle may be used. On the other hand, when exposure is difficult even with far ultraviolet light and exposure light of a shorter wavelength is required, the movable reflecting mirror 44 is removed from the traveling direction of the scattered light passing through the electron beam deflecting means 42, and 2 exposure apparatus. The second exposure apparatus may have the same configuration as that shown in FIG.

The optical wavelength shortening device according to the second embodiment shown in FIG. 5 can be combined with the optical wavelength shortening device according to the first embodiment shown in FIG. It can be combined with the modified example of the optical wavelength shortening device of the first embodiment, or can be combined with the optical shortened wavelength device of the first embodiment shown in FIGS. 1 and 4 and its modified example.

Although the present invention has been described based on the embodiments of the present invention, the present invention is not limited to these embodiments. Conditions and numerical values in the optical wavelength shortening apparatus described in the embodiment of the invention, the structure of the optical wavelength shortening apparatus is an example,
The design can be changed as appropriate. For example, the emission direction of the electron beam from the electron beam source is directed upward, the upwardly emitted electron beam is horizontally deflected by the electron beam deflecting means, and the laser beam emitted upward from the laser light source and the inside of the vacuum chamber. By adopting a structure in which collision occurs, the size of the optical wavelength shortening device can be reduced. Alternatively, the direction of emission of the electron beam from the electron beam source is set to the horizontal direction, and the electron beam emitted in the horizontal direction is deflected to 90 degrees by the electron beam deflecting means. The size of the optical wavelength shortening device can also be reduced by employing a structure in which the laser beam emitted in parallel with the direction of emission of the electron beam from the laser beam collide in the vacuum chamber. The configuration of the angle changing means is also an example. If the configuration can change the traveling direction of the laser beam, the angle of the reflecting mirror, and the trajectory of the electron beam,
Any configuration is possible.

In the optical wavelength shortening device whose conceptual diagram (conceptual plan view) is shown in FIG. 6, the periphery of electron beam deflecting means (deflecting electromagnets 42 and 42A) for deflecting the electron beam and the electron beam Radiation shielding members 60 made of iron or lead are arranged around the damper, and these radiation shielding members 60 also serve as structural materials of the optical wavelength shortening device.
Also serves as an anti-vibration mount for the exposure apparatus. That is, an exposure device (not shown) is arranged on the radiation shielding member 60. With such a structure, it is possible to reduce the floor occupied area of the optical wavelength shortening apparatus including the exposure apparatus.

[0042]

According to the present invention, an electromagnetic wave (ultraviolet ray or soft X-ray) having a desired wavelength can be obtained with a high degree of freedom, and the energy of the electron beam from the electron beam source varies. However, such a change does not appear as a change in the wavelength of the light whose wavelength has been shortened. Alternatively, since the wavelength of the shortened light can be easily changed, the wavelength of the exposure light can be easily changed even when the design rule of the semiconductor device is changed. In addition, since the apparatus is not basically a complicated structure as far as the left, can be manufactured at low cost and is compact, one light source for one X-ray reduction exposure apparatus is used as a light source of the X-ray reduction exposure apparatus. It is possible to incorporate an optical wavelength shortening device. In addition, since contaminants such as metal ions and particles are not generated in principle as in a laser-induced plasma X-ray source,
The maintenance of the optical wavelength shortening device is easy, the lifetime of the device is long, and there is no need to replace the target.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an optical wavelength shortening device according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of an example of an exposure apparatus in a lithography technique in manufacturing a semiconductor device.

FIG. 3 is a diagram showing a scattered light (soft X ray) that has passed through an electron beam deflecting means for a test in the optical wavelength shortening apparatus shown in FIG.
(Line) is a graph showing the results of measurement with a multi-channel plate.

FIG. 4 is a conceptual diagram of a modified example of the optical wavelength shortening device according to the first embodiment of the present invention.

FIG. 5 is a conceptual diagram of an optical wavelength shortening device according to a second embodiment of the present invention.

FIG. 6 is a conceptual diagram of a modified example of the optical wavelength shortening device of the present invention.

[Explanation of symbols]

10: Optical wavelength shortening device, 11: Electron gun, 12
..Current monitor, 13 ... Pre-buncher and buncher, 14 ... Converging lens system, 15 ... Klystron, 16 ... Detector, 20 ... Laser light source, 2
1 ... reflecting mirror, 22 ... actuator, 23 ...
A second reflecting mirror, 24 a collision area, 25 an electromagnet for changing an angle, 26 a pedestal, 30 a vacuum chamber, 41 a laser beam damper, 42 ...
Electron beam deflecting means, 43 ... electron beam damper,
44 movable mirror, 50 illumination optical system, 51
... Reflection type mask, 52 ... Reduction optical system, 53 ...
・ Semiconductor substrate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayoshi Shinmine 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Yuji Kaneda 7-35, Kita-Shinagawa, Shinagawa-ku, Tokyo No. 72 Inside Sony Corporation (72) Inventor Hideaki Ogaki 1-1-4 Umezono, Tsukuba City, Ibaraki Prefecture Within the Institute of Technology, Electronic Technology Research Institute (72) Inventor Hiroyuki Toyokawa 1-4-1 Umezono, Tsukuba City, Ibaraki Prefecture Industrial (72) Inventor: Tomohisa Triangle 1-4-1, Umezono, Tsukuba, Ibaraki Pref. AB02 AC10 JJ20 QQ01 YY08

Claims (8)

[Claims] 1. An electron beam source, a laser light source, and a vacuum chamber, wherein an electron in an electron beam emitted at a relativistic speed emitted from the electron beam source and a photon in a laser beam emitted from the laser light source. In a vacuum chamber,
Giving the energy of the electrons to the photons of the laser beam,
An apparatus for shortening the wavelength of scattered light, comprising: an angle for changing a collision angle between a laser beam and an electron beam before a collision between an electron and a photon in order to change a wavelength of the scattered light. An optical wavelength shortening device comprising a changing unit. 2. The angle changing means comprises a reflecting mirror and a reflecting mirror angle changing means disposed in a vacuum chamber, wherein the reflecting mirror has a collision area where electrons and photons collide, a laser light source, 2. The optical wavelength shortening device according to claim 1, wherein the device is arranged so as not to collide with an electron beam incident on the collision region. 3. The vacuum chamber according to claim 2, further comprising a second reflecting mirror disposed in the vacuum chamber so as not to collide with the scattered light emitted from the collision area. Optical wavelength shortening device. 4. The angle changing means comprises an electromagnet, wherein the electromagnet is provided between a collision area where electrons and photons collide and an electron beam source.
3. The optical wavelength shortening device according to claim 1. 5. The apparatus according to claim 1, wherein the energy of the electron beam emitted from the electron beam source is 1 × 10 ⁷ eV or less. 6. The optical wavelength shortening apparatus according to claim 4, wherein the energy of the electron beam emitted from the electron beam source is 1 × 10 ⁵ eV or more. 7. The apparatus according to claim 1, wherein the electron beam source comprises an electron gun, a buncher, and a focusing lens system. 8. An electron beam source, a laser light source, and a vacuum chamber, wherein electrons in the electron beam emitted from the electron beam source and moving at a relativistic speed, and photons in the laser beam emitted from the laser light source, In a vacuum chamber,
Giving the energy of the electrons to the photons of the laser beam,
An apparatus for shortening the wavelength of scattered light, wherein the energy of an electron beam emitted from an electron beam source is 1 × 10 ⁷ eV or less.