JPS62208631A - Reduction type x-ray lithography equipment - Google Patents

Abstract

PURPOSE:To make it feasible to perform fine processing not exceeding 1mum using existing aligner and stepper by making use of an assymetric Bragg reflection phenomenon of X-rays due to single crystal. CONSTITUTION:The titled lithgraphy equipment is provided with a monochromator 3 letting X-rays with specified wavelength only pass there- through, the first reflecting mirror 4 reflecting the X-rays from the monochromator 3 in the X direction and the second reflecting mirror 5 reflecting the X-rays reflected by the first mirror in the Y direction while the first and the second reflecting mirrors 4, 5 are composed of assymetric Bragg reflecting mirrors of X-rays due to single crystal. A specified pattern is described in a mask 6 arranged between the monochromator 3 and the first reflecting mirror 4. The pattern described in the mask 6 is not of the same size (1:1) as that of the final exposure pattern but several times larger than that of the same. Finally, an exposure substrate 7 coated with a resist film irradiation-exposed to X-rays transferred through the second reflecting mirror 5 is provided.

Description

[Detailed description of the invention] b) Industrial application field The present invention relates to a compact X-ray phosphorography device.

(Example) Conventional technology In the semiconductor field, visible light and ultraviolet light cannot be used for microfabrication of less than one circle because their wavelengths are too long.

Therefore, it has been proposed to use X-rays with a shorter wavelength than those lights, and some of them are being put into practical use. For example, page 364 (3P-A-1) of the Proceedings of the 29th Federation of Applied Physics Conference
8) Article 1: Examination of exposure characteristics of resist using synchrotron radiation.

C) Problems to be Solved by the Invention However, since there is no lens that can be used in the X-ray region, the reduction projection method normally used in photolithography cannot be employed. Therefore, aligners and steppers for 1:1 transfer are being developed. However, in order to overlay and transfer several types of patterns with a line width of 174, the mask alignment accuracy must be 0. Since something higher than OIIm is required, the appearance of highly accurate aligners and steppers is currently awaited.

2) Means for solving the problems The present invention solves the problems by using the asymmetric Bragg reflection phenomenon of X-rays by a single crystal.

(e) Operation By using the asymmetric Bragg reflection phenomenon of X-rays by a single crystal, a reduction projection method similar to that of ordinary photolithography can be employed, even though the method is in the X-ray region.

f) Example FIG. 2 shows the asymmetric Bragg reflection phenomenon of X-rays by the single crystal used in the present invention. The same figure (a) is Bra/G anti-I4.
This is an explanatory diagram of the principle of X-rays (2) incident on the lattice plane of a single crystal (1) schematically shown by equally spaced parallel lines at a Bragg angle θ and reflected symmetrically.

On the other hand, if the crystal surface on which the X-rays are incident is tilted by an angle α with respect to the lattice plane, as shown in Figure 2(b), the X-ray reflection conditions will not change, but the width of the X-ray flux will change. . Various Bragg angles θ can be selected depending on the type of crystal, the reflective surface used, and the wavelength of the X-rays used, and the lattice plane can be reduced depending on the combination of the angle with the incident X-rays and the Bragg angle of 0. The rate can be controlled arbitrarily.

FIG. 1 shows the configuration of the apparatus of the present invention. In the same figure, (3
) is a monochromator that allows only X-rays of a desired wavelength to pass through, (4) is a first reflecting mirror that reflects X-rays of a desired wavelength obtained from this monochromator in the X direction, and (5) is a first mirror. This is a second reflecting mirror that reflects the X-rays reflected by the Consists of an asymmetric Bragg reflector. (6> is a mask placed between the monochromator and the first reflecting mirror (4), on which a desired pattern is drawn. This mask (6)
) is the final exposure pattern and 1
= 1, but several times as large. (7) is an exposed substrate coated with a resist film which is exposed to X-rays obtained through the second reflecting mirror (5).

Next, specific examples of the present invention will be described by citing numerical values.

The ratio of the width a of the incident ray bundle to the width of the reflected ray bundle is a:b=sin
(θ+a): 5 inches (θ−a).

- As an example, take the case where X-rays with three wavelengths are reflected by (111) reflection of a silicon single crystal (lattice constant: 5.4301). The Bragg angle is θ=28.585'.

The reduction rate when changing the tilt angle of the crystal surface is a=10
．． At 30° a:b = 2:1a = 19.98@
When a: b = 5:1.2 = 24.05 @ when a
:b=10:1.

The closer the angle is to θ, the greater the reduction rate will be. Theoretically, the usable angle range is Q<d<θ<45m, but when 0 is close to 45°, the X-ray reflectance decreases, and θ=
Since it becomes O at 45', the range that can actually be used is a little narrower. Silicon is used as the crystal, but if it is a perfect crystal, a heavier crystal like germanium is preferable. If it is necessary to use X-rays with longer wavelengths, a single crystal with a large lattice constant is required.

g) Effects of the Invention As is clear from the above description, the present invention uses a pair of reflecting mirrors that are inclined with respect to the lattice plane to reflect the single crystal surface on which X-rays are incident in directions perpendicular to each other. ,
X-rays can be substantially focused without using a lens system. As a result, microfabrication of 11JI'11 or less becomes possible using existing aligners and steppers.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of the apparatus of the present invention, and FIG. 2 is a sectional view for explaining the basic principle of the present invention. (1)...Single crystal, (2)...X-ray, (3)...
Monochromator, (4) (5)...Reflection mirror, (6
)...Mask, (7)...Exposure substrate.

Claims (1)

[Claims] a monochromator that allows only X-rays of a desired wavelength to pass;
The monochromator includes first and second reflecting mirrors that reflect X-rays of a desired wavelength obtained from the monochromator in mutually orthogonal directions, and each of the reflecting mirrors aligns the single crystal surface on which the X-rays are incident with respect to the lattice plane. The resist film is tilted at a desired angle, and a mask is placed between the monochromator and the first reflecting mirror, and the resist film is irradiated with X-rays obtained through the second reflecting mirror. Miniaturized X-ray lithography equipment.