JPH0612755B2 - Exposure equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lithographic technique in the manufacturing process of semiconductor integrated circuits, printed circuits, optical devices (diffraction gratings, waveguides), ultrasonic devices, etc., and particularly to a light source. The present invention relates to an exposure apparatus provided with a reflection optical system for reducing and projecting a pattern onto an optical system by using a short-wavelength and high-brightness undulation radiation emitted from a high-speed electron beam by a spiral orbit type electronic meandering device (undulator).

[Prior Art] FIG. 4 is a block diagram showing an example of a conventional exposure apparatus, 1 is a mercury lamp, 2 is an illumination lens, 3 is a reticle, 4 is a projection lens, 5 is a wafer, and 6 is a stepper.

In the above-mentioned conventional exposure apparatus used for photolinography of a semiconductor integrated circuit, an ultrahigh pressure mercury arc lamp or a xenon mercury arc lamp is used as a mercury lamp 1 as a light source. In the case of the mercury lamp 1, the spectral lines used for exposure are mainly g-line (wavelength 435.8 nm) and h
Reduction projection exposure using i-line (365 nm) is being studied aiming at a shorter wavelength, which is ultraviolet ray of line (404.7 nm). As shown in FIG. 4, reduction projection is generally performed by making an actual pattern called a reticle 3 (original of an IC circuit pattern) magnified 5 to 10 times, and the pattern reduced by the lens system is formed on the wafer 5. This is a method of exposing the resist. The reticle 3 usually has a pattern including several chips, and the stepper 6 exposes the pattern on the wafer 5 one after another. Therefore, this whole device is abbreviated as a stepper.

[Problems to be Solved by the Invention]

However, the conventional lithographic technique uses the reticle 3
Since the fine pattern depicted in (1) is projected by the illumination lens 2, if the pattern becomes too fine, blurring (diffraction) of the same degree as the wavelength of light used for pattern transfer occurs. Therefore, the wavelength of light used must be shortened as the pattern becomes finer. At present, the mercury lamp 1 is used for exposure, and its wavelength is about 0.4 μm. Therefore, this light cannot be used for ultra-ultra LSIs having a line width of about 0.5 μm or less. Therefore, as light with shorter wavelength (electromagnetic wave), for example, use of radiated light (electromagnetic wave) in the x-ray region generated by an excimer laser (0.193 μm in the case of ArF), an x-ray tube, or a deflection electromagnet portion of an electron storage ring is attempted. However, in the case of an excimer laser, the problem of continuous oscillation duration has been pointed out. Regarding the x-ray of the synchrotron radiation, it is necessary to form a fine pattern of the same size as the pattern on the wafer 5 on the mask (corresponding to the reticle 3 in FIG. 4) for equal-magnification exposure. Becomes difficult. Further, the x-ray irradiation has problems such as radiation damage on the mask and heat load causing the pattern to be distorted.

The present invention has been made to solve the above-mentioned conventional problems, and uses a spiral orbital undulator as a stable light source with high brightness in the far-ultraviolet / vacuum-ultraviolet region, and reduces projection of a pattern by a reflection optical system. By doing, 0.4 μm
An object of the present invention is to obtain an exposure apparatus which can expose a pattern having the following line width in a short time.

[Means for Solving the Problems]

An exposure apparatus according to the present invention comprises an exposure chain having a spiral orbital undulator inserted in an electron storage ring and a reflection optical system for reducing and projecting undulator radiation light generated from the spiral orbital undulator as a light source. Is.

[Action]

In the present invention, the undulator radiation generated from the spiral orbital undulator is used, and the pattern is reduced and projected by the reflecting mirror to obtain the exposure with a line width of 0.4 μm or less.

〔Example〕

1 (a) and 1 (b) show an embodiment of the present invention. FIG. 1 (a) shows a structure in which an electron storage ring and a linear accelerator as an electron beam injector are added to the entire exposure apparatus. FIG. 1 (b) is a diagram showing the configuration of the main optical system in the exposure chain of FIG. 1 (a), and FIG. 2 is a spiral orbital undulator used in the exposure apparatus of FIG. It is a figure which shows the structure of. In these figures, 10 is a spiral orbital undulator, 11 is an electron storage ring, 12 is an exposure chain, 13 is a window for extracting emitted light, 14 is a bending magnet, and
5 is a quadrupole magnet, 16 is a high frequency accelerating cavity for applying energy to the stored electron beam, 17 is an inflector,
18 is a parter beta, 19 is the electron storage ring 1
1, a linear accelerator for injecting an electron beam, 20 undulator radiation, 21 a reflecting mirror, 22 a reticle (mask), 23 a reticle stage, 24 a Schwarzschild type reflecting mirror, a convex mirror 24a and an annular concave mirror 24b, the light reflected by the convex mirror 24a is reflected by the concave mirror 24b and forms an image on the wafer. 25 is a wafer, 26
Is a step stage, 27 is an electron beam, and 28 is a permanent magnet array.

Next, the operation will be described.

By using the undulator radiation 20 as a light source, high brightness can be easily achieved in the far ultraviolet / vacuum ultraviolet region. The spiral orbital undulator 10 is a quasi-monochromatic light source that causes a passing high-speed electron to rotate many times to interfere with a specific wavelength.

The spiral orbital undulator 10 having the permanent magnet array 28 as shown in FIG. 2 produces high-intensity light because electrons always emit electromagnetic waves.
It is possible to cause electrons to travel on various orbits by appropriately changing the magnetic field strength of each magnet or changing the magnet array. [Electronic Research Institute News 462 (July 1988),
Polarization generator: Japanese Patent Application No. 59-137655, H. Onukie
by t al Polarizing undulator with crossed and retard
ed magnetic fields: Rev.Sci.Instrum.Vol, 60 (1989) p
p.1838]. This facilitates homogenization of the light intensity on the illuminated surface.

The spiral orbital undulator 10 is inserted into the straight portion of the electron storage ring 11. The magnetic field has a period length of 7.6 cm and a period number of 3
9. The peak intensity of the magnetic field is 1.4 KG (gap between opposing magnet rows 6 cm), and the third from the 370 MeV accumulated electrons.
The undulator radiation 20 having a peak at 150 nm (0.15 μm) shown in the figure is obtained. This peak wavelength can be changed by electron energy. (200n
In the case of using m or less, the exposure chamber 12 is replaced with air by a rare gas or the like). This undulator radiation 20 is M
It is guided to the exposure chamber 12 through the radiant light extraction window 13 made of gF ₂ . The undulator radiation 20 is reflected in the vertical direction by the reflecting mirror 21, passes through the reticle 22, and then the wafer 2 is reflected by the Schwartschild type reflecting mirror 24.
5 is projected. The pattern on the reticle 22 is about 1 /
It is reduced to 4 and imaged on the wafer 25. Also, 1.4
Exposure with a line width of μm or less is possible. With the spiral orbital undulator 10 having a total length of 3 m, when the accumulated current is 250 mA, one exposure can be performed in about 1 second.

〔The invention's effect〕

As described above, the present invention includes the spiral orbital undulator inserted in the electron storage ring, and the exposure chimber having the reflection optical system for reducing and projecting the undulator radiation light generated from the spiral orbital undulator as a light source. Therefore, exposure of a pattern having a line width of 0.4 μm or less can be realized in a shorter time than before. Reticle (mask)
Can be manufactured by the conventional technique, and the conventional resist material can be used, so that no new development is required for the mask and the resist. By using the spiral orbital undulator as the light source, the brightness is higher than that of the conventional planar undulator, and thus the straight portion of the electron storage ring may be short. Further, since the generation of harmonics is small from the electrons in the spiral orbit, the deterioration of the MgF ₂ window for emitting the emitted light from the electron storage ring can be suppressed to the minimum. Further, the spiral orbital undulator has an advantage that the exposure area can be easily adjusted to the size of the reticle because the spread of light can be changed by changing the gap between the magnet rows facing each other.

[Brief description of drawings]

1 (a) and 1 (b) show an embodiment of the present invention. FIG. 1 (a) is a diagram showing the entire structure of an exposure apparatus and a linear accelerator, and FIG. 1 (a) is a diagram showing a configuration of a main optical system of an exposure chain, FIG. 2 is a diagram showing a configuration of a spiral orbit type undulator used in the exposure apparatus of FIG. 1, and FIG. 3 is a diagram of undulator radiation light. FIG. 4 is a diagram showing a spectrum, and FIG. 4 is a configuration diagram showing an example of a conventional exposure apparatus. In the figure, 10 is a spiral orbital undulator, 11 is an electron storage ring, 12 is an exposure chainer, 13 is a window for extracting synchrotron radiation, 17 is an inflector, 19 is a linear accelerator, 20 is undulator synchrotron radiation, and 21 is a reflecting mirror. 22 is a reticle, 23 is a reticle stage, 24 is a Schwartschild type reflecting mirror, 25 is a wafer, and 26 is a step stage.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location // G21K 1/06 K 8607-2G H01S 3/30 A 8934-4M H05H 13/04 9014-2G

Claims (1)

[Claims] 1. An exposure apparatus comprising: a spiral orbital undulator inserted in an electron storage ring; and a reflection optical system for reducing and projecting undulator radiation light generated from the spiral orbital undulator as a light source.