JPH0990099A - X-ray reflection optical system and X-ray projection exposure apparatus including the optical system - Google Patents

Abstract

(57) Abstract: An X-ray reflection optical system using a multilayer X-ray reflecting mirror, in which formation of a multilayer film is relatively easy, production efficiency is high, and aberration of the optical system can be easily reduced. An object of the present invention is to provide an X-ray projection exposure apparatus equipped with the X-ray reflection optical system. An X-ray reflection optics including at least a multilayer film X-ray reflecting mirror having an X-ray reflecting multilayer film formed on a substrate and a reflecting mirror holding member for holding the multilayer film X-ray reflecting mirror. In the system, the reflecting mirror holding member is joined to the multilayer film X-ray reflecting mirror 1 by an electrostatic force, and the joining is released by releasing the electrostatic force. An X-ray reflection optical system comprising: a film X-ray reflecting mirror 1; and a power supply unit 3 for generating an electrostatic force by applying a voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray reflection optical system using a multilayer X-ray reflection mirror and an X-ray projection exposure apparatus equipped with the X-ray reflection optical system.

[0002]

2. Description of the Related Art An exposure apparatus for manufacturing a semiconductor device projects and transfers a circuit pattern formed on a photomask (hereinafter, referred to as a mask) surface as an object surface onto a substrate such as a wafer via an imaging optical system. I do. A resist is coated on the substrate, and the exposure exposes the resist to light to obtain a resist pattern.

The resolving power w of an exposure apparatus is determined mainly by the exposure wavelength λ and the numerical aperture NA of the imaging optical system, and is expressed by the following equation. w = kλ / NA k: constant Therefore, in order to improve the resolving power, it is necessary to shorten the wavelength or increase the numerical aperture. At present, the exposure equipment used in the manufacture of semiconductors mainly uses i-line with a wavelength of 365 nm.
A resolution of 0.5 μm is obtained.

Since it is difficult to increase the numerical aperture in terms of optical design, it is necessary to shorten the wavelength of the exposure light in the future in order to improve the resolution. An example of the exposure light having a wavelength shorter than the i-line is an excimer laser, and the wavelength thereof is 248 nm for KrF and 193 nm for ArF. Therefore, K
Resolutions of 0.25 μm for rF and 0.18 μm for ArF can be obtained.

Then, as the exposure light, X having a shorter wavelength is used.
When a line is used, a resolution of 0.1 μm or less can be obtained at a wavelength of 13 nm, for example. FIG. 7 conceptually shows a configuration (part) of a conventional exposure apparatus (one example). The exposure apparatus is mainly composed of a light source and an illumination optical system (not shown), a mask 11, an imaging optical system 15, and a stage (not shown) of the wafer 12.

The mask 11 is formed with an equal size or enlarged pattern of the pattern to be drawn. Imaging optical system 15
Is composed of a plurality of lenses, reflecting mirrors, or the like, and is adapted to form an image of the pattern on the mask 11 on the wafer 12. In order for the exposure apparatus to have the desired resolution,
At least the imaging optical system 15 needs to be an aberration-free or near-aberration-free optical system. If the imaging optical system 15 has an aberration, the cross-sectional shape of the resist pattern is deteriorated, which adversely affects the process after exposure and causes a problem that the image is distorted.

The aberration value (rms value) for obtaining the same performance as that of no aberration needs to be about 1/14 of the wavelength. Therefore, as the wavelength becomes shorter, the value of the aberration must be made smaller. The aberration required when the exposure light is the i-line is about 26 nmrms. In order to produce an aberration-free optical system, the shape of each optical element must first be processed according to the design value. The required shape precision is at least smaller than the required aberration, and the larger the number of optical elements, the smaller the required shape precision value.

If all the optical elements are lenses,
If the number of refracting surfaces is N, the shape error is 1 / N ^{1/2 of the} aberration.
You need some value. For example, if the exposure light is i-line and the number of refraction surfaces is 30, the required shape error is about 5 nmr.
It becomes ms. Next, the optical element thus manufactured must be aligned and assembled with high precision. The assembling accuracy can be obtained by optical calculation, but if the exposure light is the i-line, it is necessary to perform alignment on the order of at least μm.

As described above, in order to manufacture an aberration-free optical system, high processing accuracy and assembling accuracy are required. Until now, however, high-accuracy processing and assembling have been performed to obtain an aberration-free optical system. Could be made. However, when the wavelength of the exposure light is shortened in order to improve the resolution of the exposure apparatus, the allowable value of the aberration becomes smaller accordingly.
When the exposure light is X-rays and the wavelength is 13 nm, the allowable value of aberration is about 1 nmrms. This value is very small compared to the aberration value at the i-line of about 26 nmrms. Therefore, the optical element is required to have higher shape accuracy.

In the case of an X-ray exposure apparatus, it is preferable that all optical systems are reflecting mirrors. Since the shape error of the reflecting surface needs to be half the value of the case of refraction, assuming that the number of reflecting surfaces is N, the necessary shape error is 1 / (2N ^1/2 ) of the aberration.
For example, if the number of reflecting surfaces is 4, the shape error at a wavelength of 13 nm is 0.23 nmrms. As described above, in the X-ray projection exposure apparatus, an extremely small value is required as the aberration of the imaging optical system, and therefore the shape accuracy of the optical element is also required to be less than nm. In the case of the X-ray projection exposure apparatus, since the multilayer film reflecting mirror is used as the optical element, the multilayer film reflecting mirror must be manufactured with high accuracy.

In the production of the multilayer-film reflective mirror, a substrate is first produced, and a multilayer film is coated on the substrate to form a reflecting surface having a desired shape. At this time, the shape of the substrate is changed and formed. It is necessary to form a multilayer film so that the reflective surface does not differ from the desired shape. At the stage of manufacturing a substrate, it is possible to obtain a desired substrate shape by performing processing such as conventional polishing with high accuracy. Also, even if the desired substrate shape cannot be obtained due to processing error,
By performing the processing again, it is possible to reduce the shape error. Further, it is possible to gradually bring the substrate shape closer to a desired shape by repeating processing and shape measurement.

That is, at the stage of manufacturing a substrate, a desired substrate shape can be obtained by processing a plurality of times even if the processing method causes a processing error.

[0013]

However, at the stage of forming a multi-layer film, it is extremely difficult to perform re-processing after forming the multi-layer film, unlike when processing the substrate. Therefore, the formation of the multilayer film needs to be performed with high accuracy and good reproducibility so as not to change the shape of the substrate, and there is a problem that the formation of the multilayer film is very difficult.

Further, when an error occurs in the formation of the multilayer film, the multilayer film reflecting mirror (the substrate and the multilayer film) must be manufactured again from the beginning, and the manufacturing efficiency of the multilayer film reflecting mirror is very poor. There was a problem. Next, after producing the multilayer-film reflective mirror in a desired shape, an optical system using such a multilayer-film reflective mirror is assembled. At this time, it is necessary to hold the multilayer-film reflective mirror.

Therefore, conventionally, the multilayer reflecting mirror is mechanically fixed to the holding member. For example, as shown in FIG. 6, an optical element fixing component 14 such as a screw is used to fix the multilayer reflecting mirror. The multilayer-film reflective mirror 1 was fixed by pressing it against 1. However, if the multilayer mirror is held by such a method, the stress applied to the multilayer mirror deforms the reflective surface of the multilayer mirror, and as a result, the aberration of the optical system using the multilayer mirror is reduced. There was a problem that it was very difficult to do.

As described above, in the conventional multilayer film reflecting mirror, it is very difficult to form a multilayer film, the manufacturing efficiency of the multilayer film reflecting mirror is very low, and the aberration of the optical system using the multilayer film reflecting mirror is very low. It was very difficult to reduce The present invention has been made in view of the above problems, and uses a multi-layer film X-ray reflecting mirror in which formation of a multi-layer film is relatively easy and production efficiency is good, and aberration of an optical system is easily reduced. It is an object of the present invention to provide an X-ray reflection optical system and an X-ray projection exposure apparatus including the X-ray reflection optical system.

[0017]

Therefore, the present invention is firstly directed to "at least a multilayer film X-ray reflecting mirror having an X-ray reflecting multilayer film formed on a substrate and the multilayer film X-ray reflecting mirror. In an X-ray reflection optical system including a reflecting mirror holding member, the reflecting mirror holding member is joined to the multilayer film X-ray reflecting mirror by electrostatic force, and the detachable holding is released by releasing the electrostatic force. X-ray reflection optical system (claim 1), characterized in that the X-ray reflection optical system (claim 1) has a section and a power supply section for applying a voltage between the holding section and the multilayer film X-ray reflection mirror to generate an electrostatic force. provide.

A second aspect of the present invention is that "one of the multilayer X-ray reflecting mirror and the holder is made of a dielectric material and the other is made of a metal or a semiconductor. X-ray reflection optical system (claim 2) ". In the third aspect of the present invention, "of the holding portions,
The shape of the portion of the multilayer film X-ray reflecting mirror that is not joined and the shape of the portion of the multilayer film X-ray reflecting mirror that is joined to the holding portion are the same or substantially the same. The X-ray reflection optical system (claim 3) according to claim 1 or 2 is provided.

In a fourth aspect of the present invention, "a shape of a portion of the holding portion that is joined to the multilayer film X-ray reflecting mirror in a non-joined state, and the holding portion of the multilayer film X-ray reflecting mirror. The X-ray reflection optical system (claim 4) according to claim 1 or 2, wherein the shape of the part to be joined to the part is such that it is fitted to each other. A fifth aspect of the present invention is that, in the holding portion, the multilayer film X is
The shape of the portion of the multilayer film X-ray reflecting mirror that is joined to the holding portion, and the shape of the portion that is joined to the holding portion of the multilayer film X-ray reflecting mirror when not joined are The X-ray reflection optical system (claim 5) according to claim 1 or 2, wherein the reflection surface shape of the film X-ray reflecting mirror is set to be a predetermined shape.

A sixth aspect of the present invention provides an "X-ray projection exposure apparatus having the X-ray reflection optical system according to claims 1 to 5 (claim 6)".

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a multilayer film X according to the present invention.
It is a block diagram which shows an example of the line reflection mirror 1 and a reflection mirror holding member. The reflecting mirror holding member is joined to the multilayer film X-ray reflecting mirror 1 by an electrostatic force, and the detachable holding unit 2 is released by releasing the electrostatic force, and the holding unit 2 and the multilayer film X-ray reflecting member. It has a power supply unit 3 that applies a voltage between the mirror 1 and the mirror 1 to generate an electrostatic force.

That is, when a voltage is applied between the holding part 2 and the multilayer film X-ray reflecting mirror 1, an electrostatic force (attracting force) is generated between the two, and the multilayer film X-ray reflecting mirror 1 is held on the holding part 2. Fixed. If one of the multilayer X-ray reflecting mirror 1 and the holding unit 2 according to the present invention is made of a dielectric and the other is made of a metal or a semiconductor, a strong electrostatic force is obtained when a voltage is applied between the two, and As a result, the multi-layer film X-ray reflecting mirror 1 is strongly fixed to the holding portion 2 (claim 2).

It is general that the multilayer film X-ray reflecting mirror 1 is made of a dielectric material (for example, a multilayer film is formed on a glass substrate) and the holding portion 2 is made of metal, but the combination is limited. Not a thing. Of the holding part 2, the multilayer film X-ray reflecting mirror 1
Of the shape of the multilayer film X-ray reflecting mirror 1 in the non-bonding shape of the portion bonded to (hereinafter, referred to as the bonding portion of the holding portion 2),
If the shape of the portion joined to the holding portion 2 (hereinafter, referred to as the joined portion of the multilayer film X-ray reflecting mirror) when not joined is the same or substantially the same, both joined portions are likely to adhere to each other,
It is preferable because the multilayer X-ray reflecting mirror 1 can be fixed to the holding portion 2 with little or no deformation (claim 3).

If the shape of the joint of the holding portion 2 when not joined and the shape of the joint of the multilayer film X-ray reflecting mirror 1 when not joined are such that they fit together, both joints will adhere to each other. This is preferable because the multi-layer film X-ray reflecting mirror 1 can be fixed to the holding portion 2 without being deformed or hardly deformed (claim 4). FIG. 2A shows a state in which the multilayer film X-ray reflecting mirror 1 having a planar joint shape is fixed to the holding portion 2. As shown in FIG. 2A, if the joint portion 6 of the multilayer film X-ray reflecting mirror 1 and the joint portion 7 of the holding portion 2 have the same shape (planar shape in this example), the multilayer film X-ray reflecting mirror. 1 is fixed to the holder 2 without being deformed (FIG. 2 shows that the plane mirror 5 is a plane mirror even if it is fixed to the holder 2).

When the reflecting surface 5 of the multilayer X-ray reflecting mirror 1 is formed in a desired shape, it is necessary to fix the reflecting mirror 1 to the holding portion 2 so that the multilayer X-ray reflecting mirror 1 is not deformed. Therefore, as described above, it is preferable that the joint portion 6 of the multilayer X-ray reflecting mirror 1 and the joint portion 7 of the holding portion 2 have the same shape or a fitting shape. Further, when the joint portion 6 of the multilayer film X-ray reflecting mirror 1 and the joint portion 7 of the holding portion 2 are formed into a shape (for example, a flat surface or a spherical surface) that can be easily processed with high precision, they should be processed into the same shape or a fitting shape. Is preferred, which is preferable.

On the other hand, when the joint portion 6 of the multilayer X-ray reflecting mirror 1 and the joint portion 7 of the holding portion 2 have different shapes or do not fit, as shown in FIG. Line reflector 1
The multi-layer film X-ray reflecting mirror 1 is deformed when it is fixed to the holding portion 2. However, if this deformation is positively utilized, it becomes possible to adjust (correct) the reflection surface shape when fixing the multilayer X-ray reflecting mirror 1 to the holding portion 2.

That is, the shape of the portion of the holding portion that is joined to the multilayer film X-ray reflecting mirror when not joined and / or the shape of the portion of the multilayer film X-ray reflecting mirror that is joined to the holding portion is not. It is preferable to set the shape at the time of joining so that the shape of the reflecting surface of the multilayer film X-ray reflecting mirror becomes a predetermined shape at the time of joining, because the shape of the reflecting surface can be adjusted (corrected) (claim 5).

That is, the multilayer film X-ray reflecting mirror 1 produced by the substrate processing error of the multilayer film X-ray reflecting mirror 1, the film thickness distribution error at the time of forming the multilayer film, or the shape change due to the internal stress of the multilayer film. If the shape of the reflection surface 5 is not the desired shape, the reflection surface 5 may be adjusted (corrected) so that the reflection surface 5 has the desired shape with the multilayer film X-ray reflecting mirror 1 fixed to the holding portion 2.

For example, in order to adjust the reflecting surface, which is a curved surface when the multi-layer film X-ray reflecting mirror 1 is not fixed, to be a flat surface when the multi-layer film X-ray reflecting mirror 1 is fixed, as shown in FIG. The joint part 6 of FIG. 3 is curved (FIG. 3a), or the holding part 2
It is sufficient to process the joint portion 7 of (1) into a curved surface (FIG. 3b). In this example, in any case, when the joint portion 6 of the multilayer X-ray reflecting mirror 1 comes into close contact with the joint portion 7 of the holding portion 2, the multilayer X-ray reflecting mirror 1 is deformed and the reflecting surface 5 is curved. Changes from to a plane.

When the multi-layer film X-ray reflecting mirror 1 is fixed to the holding portion 2, in order to change the shape of the reflecting surface 5 of the multi-layer film X-ray reflecting mirror 1 into a desired shape, The shape of the joint portion 6 and / or the joint portion 7 of the holding portion 2 to be set can be determined by calculation such as the finite element method. According to the holding of the multi-layer film X-ray reflecting mirror 1 according to the present invention, since the multi-layer film X-ray reflecting mirror 1 can be held in a large area, it is possible to freely deform (adjust) the multi-layer film X-ray reflecting mirror 1. It has the characteristic of high degree. For example, the joining portion 6 of the multilayer film X-ray reflecting mirror 1 as shown in FIG.
If processing is performed using 10, it is possible to form a spatially complicated shape, and the joint portion of the holding portion can be similarly processed.

That is, the multilayer X-ray reflecting mirror 1 can be spatially complicatedly deformed (adjusted), and as a result, it becomes easy to correct the shape error of the multilayer X-ray reflecting mirror 1. Further, if the multilayer film X-ray reflecting mirror 1 is made thin to reduce its rigidity, the amount of deformation (adjustment) can be increased.
Further, even though the shape of the reflecting surface 5 of the multilayer film X-ray reflecting mirror 1 was the desired shape before being fixed (holding), the shape of the reflecting surface 5 changed from the desired shape after being fixed (holding). If it has, or if the shape of the reflecting surface 5 is not deformed to a desired shape when it is fixed and the shape deviates from the desired shape, it is easy to correct the error.

That is, the multilayer film X once fixed to the holding unit 2.
The linear reflecting mirror 1 is removed, and the joint portion 6 of the multilayer X-ray reflecting mirror 1 and / or the joint portion 7 of the holding portion 2 is attached so that the reflecting surface 5 of the multilayer X-ray reflecting mirror 1 is deformed into a desired shape. It should be reprocessed. The removal of the multilayer film X-ray reflecting mirror 1 can be easily performed by setting the voltage applied between the multilayer film X-ray reflecting mirror 1 and the holding unit 2 by the power supply unit 3 to zero.

Further, the multilayer film X-ray reflecting mirror 1 is fixed to the holding portion 2, the reflection surface shape of the multilayer film X-ray reflecting mirror 1 is measured, and the multilayer film X.
The shape of the multilayer reflecting mirror after holding (that is,
It is possible to bring the shape of the reflecting surface) closer to the desired shape. Therefore, the optical system can be manufactured in a short time without reworking the surface (reflection surface) of the multilayer X-ray reflecting mirror 1 as in the prior art, that is, without reforming the multilayer.

It is preferable to use the X-ray reflection optical system according to the present invention in an X-ray projection exposure apparatus, because the aberration of the optical system can be reduced and the performance of the apparatus can be improved (claim 6). As described above, according to the X-ray reflection optical system of the present invention (Claims 1 to 4), the multilayer film X-ray reflection mirror can be held without deforming its shape, so that desired performance is stabilized. Can be demonstrated.

Further, according to the X-ray reflection optical system of the present invention (claims 1, 2, and 5), it is possible to change the shape of the multilayer film X-ray reflecting mirror when it is fixed. Even when the shape of the reflecting mirror is not formed into a desired shape, it can be deformed into a desired shape when fixed. That is, even a multilayer film X-ray reflecting mirror having a manufacturing error can be used without remanufacturing. Therefore, it becomes possible to manufacture an X-ray reflection optical system capable of stably exhibiting desired performance with high throughput.

The X-ray reflection optical system of the present invention (claim 1)
According to 5), it is possible to easily fix and remove the multilayer X-ray reflecting mirror. Therefore, even if it is found that the shape of the multilayer X-ray reflecting mirror is not the desired shape after fixing, the multilayer X-ray reflecting mirror should be removed and each connecting portion should be reprocessed to bring it closer to the desired shape. Is possible. Therefore, an X-ray reflection optical system having desired performance can be manufactured with high yield.

Further, the X-ray projection exposure apparatus equipped with the X-ray reflection optical system of the present invention (claims 1 to 5) has a high resolution and can form a fine resist pattern.
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0038]

【Example】

<First Embodiment> FIG. 5 is a block diagram showing an X-ray reflection optical system of this embodiment and an X-ray projection exposure apparatus equipped with the optical system.
The X-ray projection exposure apparatus includes an X-ray light source and an illumination system (not shown),
A mask 11, an imaging optical system 15, and a stage (not shown) for the wafer 12 are provided.

The image forming optical system 15 has a plurality of multilayer film X-ray reflecting mirrors 1a and a reflecting mirror holding member (having a holding portion 2a and a power source portion 3). The power supply unit 3 is a multilayer film X-ray reflecting mirror 1a.
By applying a voltage between the holding part 2a and the holding part 2a, an electrostatic force is generated between them. The multilayer X-ray reflecting mirror 1a is
It is fixed to the holding portion 2a by this electrostatic force. The exposure wavelength was 13 nm, and the mask 11 used was a reflective type. The X-rays 13 reflected by the mask 11 are reflected by the multilayer film X-ray reflecting mirror of the imaging optical system 15 and reach the wafer 12, and the mask pattern is reduced and transferred onto the wafer 12.

The multi-layer film X-ray reflecting mirror 1a is a multi-layer film formed on an aspherical glass substrate, and its reflection surface (front surface) is processed into a desired shape. It is processed into a flat surface. The holding portion 2a is made of metal, and the joint portion thereof is also processed into a flat surface. A power supply unit 3 is connected between the multilayer X-ray reflecting mirror 1a and the holding unit 2a so that a voltage can be applied.

Joining part of multilayer film X-ray reflecting mirror 1a and holding part 2
Each of the joint portions a is processed into a highly accurate flat surface. Therefore, the multilayer film X-ray reflecting mirror 1a is not deformed when fixed. When exposure was performed with the exposure apparatus of this example, a resist pattern with a minimum size of 0.1 μm could be produced. On the other hand, in the exposure apparatus using the conventional holding method, the multilayer film X-ray reflecting mirror was deformed, and a pattern of 0.1 μm size could not be obtained. <Second Embodiment> FIG. 5 is a block diagram showing an X-ray reflection optical system of this embodiment and an X-ray projection exposure apparatus equipped with the optical system.

The X-ray projection exposure apparatus comprises an X-ray light source and an illumination system (not shown), a mask 11, an image forming optical system 15, and a stage (not shown) for the wafer 12. The imaging optical system 15 includes a plurality of multilayer X-ray reflecting mirrors 1b and a reflecting mirror holding member (holding portion 2a).
And a power supply unit 3). The power supply section 3 generates an electrostatic force between the multilayer film X-ray reflecting mirror 1b and the holding section 2a by applying a voltage between them. Multi-layer film X
The line reflection mirror 1b is fixed to the holding portion 2a by this electrostatic force.

The exposure wavelength was 13 nm, and the mask 11 used was a reflection type. The X-rays 13 reflected by the mask 11 are reflected by the multilayer film X-ray reflecting mirror of the imaging optical system 15 and reach the wafer 12, and the mask pattern is reduced and transferred onto the wafer 12. The multilayer X-ray reflecting mirror 1b is a multilayer film formed on an aspherical glass substrate. However, the reflection surface (surface) shape is not processed into a desired shape due to a film formation error of the multilayer film. The joint portion of the multilayer X-ray reflecting mirror 1b is processed into a flat surface.

The holding portion 2a is made of metal, and its joint portion is also processed into a flat surface. A power supply unit 3 is connected between the multilayer X-ray reflecting mirror 1b and the holding unit 2a so that a voltage can be applied. The joint portion of the multilayer X-ray reflecting mirror 1b and the joint portion of the holding portion 2a are both processed into highly accurate flat surfaces. Therefore, the multilayer X-ray reflecting mirror 1b is not deformed when fixed.

When the multi-layer film X-ray reflecting mirror 1b was fixed to the holding portion 2a and the shape of its reflecting surface was measured, a shape error was confirmed. Therefore, the multilayer film X-ray reflecting mirror 1b was removed, and the back surface (bonding portion) thereof was processed using the partial polishing apparatus 10 (see FIG. 4). The amount of processing at this time was calculated by calculation so that the reflecting surface was deformed into a desired shape when the multilayer X-ray reflecting mirror was fixed. When the processed multilayer X-ray reflecting mirror 1c was fixed to the holding portion 2a and the shape of its reflecting surface was measured, it was confirmed that it had a desired shape.

When exposure is performed by the exposure apparatus of this embodiment,
A resist pattern with a minimum size of 0.1 μm could be produced.
On the other hand, in the exposure apparatus using the conventional holding method, the multilayer film X-ray reflecting mirror was deformed, and a pattern of 0.1 μm size could not be obtained. <Third Embodiment> FIG. 5 is a block diagram showing an X-ray reflection optical system of this embodiment and an X-ray projection exposure apparatus including the optical system.

The X-ray projection exposure apparatus comprises an X-ray light source and an illumination system (not shown), a mask 11, an image forming optical system 15, and a stage (not shown) for the wafer 12. The imaging optical system 15 includes a plurality of multilayer X-ray reflecting mirrors 1b and a reflecting mirror holding member (holding portion 2a).
And a power supply unit 3). The power supply section 3 generates an electrostatic force between the multilayer film X-ray reflecting mirror 1b and the holding section 2a by applying a voltage between them. Multi-layer film X
The line reflection mirror 1b is fixed to the holding portion 2a by this electrostatic force.

The exposure wavelength was 13 nm, and the mask 11 used was a reflective type. The X-rays 13 reflected by the mask 11 are reflected by the multilayer film X-ray reflecting mirror of the imaging optical system 15 and reach the wafer 12, and the mask pattern is reduced and transferred onto the wafer 12. The multilayer X-ray reflecting mirror 1b is a multilayer film formed on an aspherical glass substrate. However, the reflection surface (surface) shape is not processed into a desired shape due to a film formation error of the multilayer film. The joint portion of the multilayer X-ray reflecting mirror 1b is processed into a flat surface.

The holding portion 2a is made of metal, and its joint is also processed into a flat surface. A power supply unit 3 is connected between the multilayer X-ray reflecting mirror 1b and the holding unit 2a so that a voltage can be applied. The joint portion of the multilayer X-ray reflecting mirror 1b and the joint portion of the holding portion 2a are both processed into highly accurate flat surfaces. Therefore, the multilayer X-ray reflecting mirror 1b is not deformed when fixed.

When the multi-layer film X-ray reflecting mirror 1b was fixed to the holding portion 2a and the shape of its reflecting surface was measured, a shape error was confirmed. Therefore, the multilayer film X-ray reflecting mirror 1b was removed, and the joint portion of the holding portion 2a was processed using the partial polishing apparatus 10. The amount of processing at this time was calculated by calculation so that the reflecting surface was deformed into a desired shape when the multilayer X-ray reflecting mirror was fixed. When the multilayer film X-ray reflecting mirror 1b was fixed to the processed holding portion 2b and the shape of the reflecting surface was measured, it was confirmed that the desired shape was obtained.

When exposure is carried out by the exposure apparatus of this embodiment,
A resist pattern with a minimum size of 0.1 μm could be produced.
On the other hand, in the exposure apparatus using the conventional holding method, the multilayer film X-ray reflecting mirror was deformed, and a pattern of 0.1 μm size could not be obtained.

[0052]

As described above, the present invention (Claim 1)
According to the X-ray reflection optical system of (4) to (4), since the multilayer X-ray reflection mirror can be held without deforming its shape, desired performance can be stably exhibited. Also,
According to the X-ray reflection optical system of the present invention (Claims 1, 2, and 5), the shape of the multilayer X-ray reflecting mirror can be changed when the multilayer X-ray reflecting mirror is fixed. Even if it is not formed into a desired shape, it can be deformed into a desired shape when fixed. That is, the multi-layer film X having a manufacturing error
It can be used even with a line mirror without re-manufacturing. Therefore,
An X-ray reflection optical system capable of stably exhibiting desired performance can be manufactured with high throughput.

The X-ray reflection optical system of the present invention (claim 1)
According to 5), it is possible to easily fix and remove the multilayer X-ray reflecting mirror. Therefore, even if it is found that the shape of the multilayer X-ray reflecting mirror is not the desired shape after fixing, the multilayer X-ray reflecting mirror should be removed and each connecting portion should be reprocessed to bring it closer to the desired shape. Is possible. Therefore, an X-ray reflection optical system having desired performance can be manufactured with high yield.

Furthermore, the X-ray projection exposure apparatus equipped with the X-ray reflection optical system of the present invention (claims 1 to 5) has a high resolution and can form a fine resist pattern.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a multilayer film X-ray reflecting mirror 1 and a reflecting mirror holding member according to the present invention.

FIG. 2A is an explanatory view showing a state in which the multilayer film X-ray reflecting mirror 1 having a planar joint portion is fixed to the holding portion 2 without deformation, and FIG. 2B shows a joint portion having a nonplanar shape. Multilayer X-ray mirror 1
It is explanatory drawing which shows a mode that it deform | transforms and is fixed to the holding part 2.

FIG. 3 is an explanatory diagram showing how the reflecting surface of the multilayer X-ray reflecting mirror 1 changes from a curved surface to a flat surface due to fixing.

FIG. 4 is an explanatory view showing a state of processing the bonding portion of the multilayer film X-ray reflecting mirror 1 using the partial polishing apparatus 10.

FIG. 5 is a configuration diagram showing an X-ray reflection optical system of an embodiment and an X-ray projection exposure apparatus including the optical system.

FIG. 6 is a schematic view showing a conventional holding method for a multilayer X-ray reflecting mirror.

FIG. 7 is a configuration diagram showing a conventional X-ray projection exposure apparatus.

[Explanation of symbols for main parts]

 DESCRIPTION OF SYMBOLS 1 ... Multilayer film X-ray reflecting mirror 2 ... Holding part (element of holding member) of multilayer X-ray reflecting mirror 3 ... Power supply part (element of holding member) 4 ... Wiring (holding member) Element: 5 ... Reflective surface of multilayer X-ray reflector 6 ... Connection of multilayer X-ray reflector 7 ... Connection of holder 10 ... Partial polishing device 11 ... Mask 12・ ・ ・ Wafer 13 ・ ・ ・ X-ray 14 ・ ・ ・ Optical element fixing parts 15 ・ ・ ・ Imaging optical system

Claims (6)

[Claims] 1. An X-ray reflection optical system including at least a multilayer film X-ray reflecting mirror having an X-ray reflecting multilayer film formed on a substrate and a reflecting mirror holding member for holding the multilayer film X-ray reflecting mirror. In the above-mentioned, the reflecting mirror holding member is joined to the multilayer film X-ray reflecting mirror by electrostatic force, and the detachable holding part whose joining is released by releasing the electrostatic force, and the holding part and the multilayer film X-ray reflecting member. An X-ray reflection optical system comprising: a power supply unit that applies a voltage between the mirror and an electrostatic force. 2. The X according to claim 1, wherein one of the multilayer X-ray reflecting mirror and the holding portion is made of a dielectric and the other is made of a metal or a semiconductor.
Line reflection optics. 3. A shape of a portion of the holding portion, which is joined to the multilayer film X-ray reflecting mirror, when not joined, and a shape of a portion of the multilayer film X-ray reflecting mirror, which is joined to the holding portion. The X-ray reflection optical system according to claim 1 or 2, wherein the shapes when not bonded are the same or substantially the same. 4. A shape of a portion of the holding portion which is joined to the multilayer film X-ray reflecting mirror when not joined, and a shape of a portion of the multilayer film X-ray reflecting mirror which is joined to the holding portion. The X-ray reflection optical system according to claim 1 or 2, wherein the shape when not bonded is a shape that fits with each other. 5. A shape of a portion of the holding portion, which is joined to the multilayer film X-ray reflecting mirror, when not joined, and / or a portion of the multilayer film X-ray reflecting mirror, which is joined to the holding portion. The X-ray reflection according to claim 1 or 2, wherein the shape of the portion to be joined is set so that the reflecting surface of the multilayer film X-ray reflecting mirror has a predetermined shape when joined. Optical system. 6. An X-ray projection exposure apparatus comprising the X-ray reflection optical system according to claim 1.