JPH0445417A - Light beam reflecting mirror - Google Patents

Abstract

PURPOSE:To easily and accurately set the angle of incidence on a reflecting mirror by adjusting the angle by using a plane reflecting mirror which is provided successively to a curved reflecting mirror. CONSTITUTION:When the angle of incidence is different, even the reflected X rays from the same light source are different in intensity. Incident light 18 is reflected at the part of the plane reflecting mirror 15 to reach a detector 16 first. The incident light is slightly diverged, so an image of a point P4 reflected by the plane reflecting mirror and an image of a point P3 by direct light are formed on the detector 16. Both the points are made coincident to make the inclination of the plane reflecting mirror parallel to the incident light. The angle of incidence where the best wavelength band for exposure is obtained is found previously, so a moving part 17 slants the reflecting mirror 13 by the angle, so the reflecting mirror 13 is moved to the position where the curved reflecting mirror 14 is irradiated with the incident light 18. At this time, the curved reflecting mirror 14 performs accurate reflection made to correspond to the reflection of the plane reflecting mirror 15, so the reflected light from the curved reflecting mirror 14 has expected intensity and reaches a used material.

Description

[Detailed Description of the Invention] [Summary] Regarding a light beam reflector that accurately reflects light such as X-rays to a predetermined position using a curved reflector, the incident angle of the curved reflector used to effectively utilize reflected light energy The purpose of this project is to provide a light beam reflector that can accurately set the angle of light, and a flat reflector for optical axis alignment combined with a curved reflector.
It is comprised of a detector that detects the reflected light from the flat reflecting mirror, and a moving unit that changes the angle of incidence on the curved reflecting mirror to a predetermined value and moves the position of the curved reflecting mirror.

[Industrial application field]

The present invention relates to a light reflecting mirror that accurately reflects light such as X-rays to a predetermined position using a curved reflecting mirror.

In the manufacturing process of VLSI, submicron processing technology is required, and in order to extract the optimal wavelength band for X-ray exposure from light rays with high intensity and excellent parallelism such as SOR light, and to obtain higher intensity light rays, reflector mirrors are used. However, it was found that the intensity of reflected X-rays differs even if the X-rays are from the same light source when the incident angle is different. There was a request to develop a technique to easily obtain a predetermined intensity of reflected X-rays.

[Conventional technology]

FIG. 5 shows an outline of a VLSI manufacturing apparatus using X-rays. In Fig. 5, 1 is a light source of SOR (synchrotron radiation), 2 is SOR light, 3 is a reflecting mirror,
4 is an exposure chamber, 5 is a semiconductor wafer, and 6 is a resist. The SOR light 2 is an electromagnetic wave emitted by electrons moving circularly in a magnetic field due to their centripetal acceleration.
When using the soft X-rays for irradiation, the most suitable for X-ray exposure, called soft X-rays, is extracted and used by reflecting it with the reflecting mirror 3 and passing it through beryllium. Soft X-rays -3O are applied to the resist 6 on the semiconductor wafer 5 in the exposure chamber 4.
Forming a pattern in submicron units by irradiating R light 2 is called 5OR-X-ray lithography technology. At this time, a condensing mirror is used to further shorten the exposure time. A reflecting mirror 3 is actually used as a condensing mirror. Consider the reflection by the reflecting mirror 3 as shown in FIG. When the SOR light 2 is incident on the reflecting mirror 3 at an incident angle θ, it is reflected symmetrically with respect to the normal 7 at a reflection angle θ, and becomes reflected light 8 . At this time, the SOR light having a wavelength shorter than the optimum wavelength for exposure is transmitted and proceeds in the direction shown as transmitted light 9.

A reflecting mirror 3 is used to change the intensity of the SOR light 2 absorbed by the resist 6 and to prevent unnecessary light from the SOR light 2 from being used as reflected light. At this time, as the reflecting mirror 3, a curved mirror is also used in addition to a plane mirror. This is because a curved mirror can converge light rays and increase their intensity.

[Problem to be solved by the invention]

As shown in FIG. 7, in the conventional configuration, the SOR light 20 is used instead of the SOR light 2, and the reflection point R on the reflecting mirror 3 is used.
2 or R2° No matter what happens, the position P that reaches the resist 6,
In some cases, they are the same. In this case, the energy given to the resist 6 by the reflected light 11 and the energy given to the resist 6 by the reflected light 12 differed in the incident light θ2 and 01, so the obtained effects were different. In particular, when the reflecting mirror is curved rather than flat, it is difficult to adjust the angle of incidence accurately. This is because the reflecting surface of a curved reflecting mirror is curved not only in the left and right directions of the optical axis, but also in the front and back directions, so even if the incident angle differs slightly, the reflection angle will change significantly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light beam reflector that can correct the above-mentioned drawbacks and accurately set the incident angle of a curved reflector used to effectively utilize reflected light energy.

[Means to solve the problem]

FIG. 1 is a diagram showing the basic configuration of the present invention. In FIG. 1, 13 is a light reflecting mirror according to the present invention, and 14 is a reflecting mirror 1.
3 a curved reflecting mirror, 15 a flat reflecting mirror 13, 16
17 is a reflected light detector, 17 is a moving part of the reflecting mirror 13, 18 is incident light, 19 is reflected light, and 21 is direct light.

The present invention has the following configuration. That is, the curved reflecting mirror 14
a flat reflecting mirror 15 for optical axis alignment, a detector 16 for detecting the reflected light from the flat reflecting mirror 15, and a detector 16 for changing the angle of incidence on the curved reflecting mirror 14 to a predetermined value; It is constituted by a moving section 17 that moves the position of the curved reflecting mirror 14.

[Effect]

The reflected light detector 16 is typically placed between the reflective mirror 13 and a location where a material that uses light, such as a semiconductor wafer, is placed. Initially, the light reflecting mirror 13 is adjusted to reflect the incident light 1.
8 is reflected by the plane reflecting mirror 15 and reaches the detector 16. At that time, as shown in FIG. 2, when the incident light 18 reaches the plane reflecting mirror 15, the incident light has a slight spread, so that it is not reflected by the plane reflecting mirror 15 onto the detector 16. An image at 26 points and an image at 23 points due to the direct light 21 that is not reflected by the plane reflecting mirror 15 are formed. The image of the R4 point on the detector 16 by the plane reflecting mirror 15 can rapidly coincide with the 23 points of the direct light 21 when the inclination of the plane reflecting mirror 15 is adjusted. This indicates that the incident light 18 has become parallel to the plane reflected light 15. Since the angle of incidence at which the optimum wavelength band for exposure can be obtained is calculated in advance, the moving unit 17 tilts the plane reflecting mirror 15 by that angle as shown by the dotted line in FIG. When the moving part 17 or the flat reflecting mirror 15 are simultaneously tilted by the predetermined angle, the curved reflecting mirror 14 is also inclined by the intended angle, so the moving part 17 moves to a position where the incident light 18 irradiates the curved reflecting mirror 14. The entire reflecting mirror 13 is moved together with the plane reflecting mirror 15. At this time, since the positional relationship between the curved reflecting mirror 14 and the plane reflecting mirror 15 is determined in advance, the curved reflecting mirror 14 performs accurate reflection in correspondence with the reflection by the plane reflecting mirror 15. Therefore, the reflected light from the curved reflecting mirror 14 can reach the material to be used (not shown) at a predetermined intensity.

It was not possible to accurately adjust the angle of incidence using only a curved reflector, but according to the present invention, the angle can be adjusted accurately using a flat reflector attached to a curved reflector, so that the reflected light can reach the material used as designed. reach.

〔Example〕

FIG. 3 is a diagram showing the configuration of an embodiment of the present invention.

In FIG. 3, 15-1 and 15-2 are plane reflecting mirrors, which are provided on both sides of the curved reflecting mirror 14, and 17.
2 has an angle setting part and a position moving part, and is a combination of an angle measuring goniometer and an electric motor, 22 is a beam line and a conduit that guides the reflected light to the exposure chamber 4, and 24 is a light selection tool, for example. This shows a beryllium plate that only transmits soft X-rays among incident light. Plane reflector 15-1.15-2
are provided on both sides of the curved reflecting mirror 14. This is because it is easier to manufacture if the plane reflecting mirror is provided on both sides rather than only on one side. Regarding the SOR light from the light source 1, initially one plane reflecting mirror, for example 15-1, is tilted approximately parallel to the incident light by the moving unit 17, and the direct light and reflected light are detected by the detector 16. After confirming that the reflected light from the plane reflecting mirror 15-1 matches the direct light at the detector 16, the angle setting unit 17 sets the incident angle to the plane reflecting mirror 15-1 to be the predetermined amount. Tilt the plane reflecting mirror 15-1. Next, the position moving unit 17 maintains the inclination of the flat reflective mirror 15-1 and moves the curved reflective mirror 14 and the flat reflective mirror 15-2, that is, the entire reflective mirror, toward the front as shown by the arrow. . This is the horizontal direction parallel to the plane of the plane reflector. The movement is stopped at a position where the incident light 18 from the light source 1 is reflected by the curved reflecting mirror I4. Beamline 22 if necessary
It is good to adjust the tilt of the screen. In this way, a predetermined pattern can be imaged onto the resist on the wafer 5 using a mask (not shown).

FIG. 4 is a diagram showing an example in which a flat reflecting mirror 15 is provided on the back surface of the curved reflecting mirror 14 as an embodiment of the present invention. In this case, as in the case of FIG. 3, the detector detects that the inclination of the plane reflecting mirror 15 substantially coincides with the incident light 18. Next, the angle setting section tilts the plane reflecting mirror 15 (that is, the curved reflecting mirror 14 as well) by a predetermined angle. Then, it is moved, for example, upward by a position moving unit, and adjusted so that the incident light 18 illuminates the curved reflecting mirror 14.

It is effective to use a fluorescent screen as a detector for reflected X-rays because it allows the detection of reflected light to be viewed directly.

The detector 16 may be located within the exposure chamber. Further, it may be located between the reflecting mirror and the light selection tool 24. When using X-rays, a finer pattern can be obtained on the wafer.

〔Effect of the invention〕

In this way, according to the present invention, when making effective use of the light reflected by the curved reflecting mirror, it is easy to accurately set the angle of incidence on the reflecting mirror to the planned angle, so that it is possible to easily set the incident angle to the intended angle. The designed light intensity can be obtained quickly and easily.

Therefore, it has the effect of greatly improving processing uniformity in X-ray lithography technology.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle configuration of the present invention, FIG. 2 is an explanatory diagram of the operation of FIG. 1, FIGS. 3 and 4 are diagrams showing the configuration of an embodiment of the present invention, and FIG.
The figure is a diagram showing an outline of a conventional device, and FIGS. 6 and 7 are diagrams explaining the reflection of the reflecting mirror in FIG. 5. 13-Light beam reflecting mirror 14-・Curved reflecting mirror 15...Flat reflecting mirror 16...Reflected light detector 17...-Moving section 18...Incoming light 21...Direct light 9... Reflected light patent applicant Fujitsu Ltd. Agent Patent attorney Eisuke Suzuki Figure 1 Figure 2 Detector Conventional device Figure 5 Explanation of reflected light Explanation of reflected light Figure 7

Claims (1)

[Claims] 1. A flat reflecting mirror (15) for optical axis alignment, which is included in the curved reflecting mirror (14), and a detector (15) for detecting the reflected light from the flat reflecting mirror (15).
16); and a moving unit (17) that changes the angle of incidence on the curved reflector (14) to a predetermined value and moves the position of the curved reflector (14). Reflector. 2. The plane reflecting mirror according to claim 1 is provided on one or both sides of the curved reflecting mirror, and the moving part is parallel to the plane of the plane reflecting mirror so that the reflected light from the curved reflecting mirror reaches a predetermined place. A light reflecting mirror characterized by being configured to be movable in the horizontal direction. 3. A light reflecting mirror according to claim 1, wherein the plane reflecting mirror is provided on the back surface of the curved reflecting mirror, and the movable part is configured to be movable up and down after adjustment by the plane reflecting mirror. .