JP2002303695A - Multi-layer film reflection mirror, removing method for multi-layer film and exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-layer film reflection mirror, removing method for the multi-layer film capable of removing the multi-layer film without damaging a substrate surface and an exposure device. SOLUTION: In the removing method for the multi-layer film, a multi-layer film reflection mirror provided with a substrate 41, an electrode layer 42 consisting of a chemically stable material formed on the substrate, a solving layer 43 formed on the electrode layer and consisting of a material with lower oxidation/reduction electric potential than the electrode layer, a multi-layer film 44 formed on the solving layer and layered with first layers of material with small difference of refractive index for soft X-ray region and that in vacuum and second layers of material with large difference by turns are prepared. The multi-layer reflection mirror is dipped in an electrolytic solution tank. Another electrode substrate is dipped in the electrolytic solution tank and a negative voltage is impressed to the electrode substrate and a positive voltage is impressed to the electrode layer to remove the solution layer by the electrolytic method. In this manner, the multi-layer film is removed from the substrate and the electrode layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer mirror, a multilayer film peeling method and an exposure apparatus, and more particularly to a multilayer mirror capable of peeling a multilayer film without damaging a substrate surface. The present invention relates to a peeling method and an exposure apparatus.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of semiconductor integrated circuit elements, in order to improve the resolution of an optical system which is limited by the diffraction limit of light, a reduced projection lithography technique (Extreme Ultra Violet Litho
graphy; hereinafter, referred to as EUVL. ) Has been developed.

[0003] Since soft X-rays have a shorter wavelength than conventionally used ultraviolet rays, a finer circuit pattern can be projected and exposed. In the wavelength region of soft X-rays, the refractive index of a substance is very close to the refractive index of vacuum (= 1), so that an optical element utilizing refraction generally used in the visible light region cannot be used. Therefore, a multilayer mirror that obtains a high reflectance by adjusting the phases of the reflected light at the interface of the materials having slightly different refractive indexes is used.

An optical system is composed of only a mirror, and in order to obtain a high resolution, an aspherical substrate (for example, an elliptical surface or a paraboloid) is often used for the mirror. Processing an aspheric surface is more difficult than processing a spherical surface. As a method of processing the substrate into an aspherical surface, for example, there is a method of forming a spherical surface on the substrate surface and then partially processing a deviation from the spherical surface to finish the aspherical surface. Small tools and the like that can do this have been developed.

After the aspherical processing of the substrate is completed, a soft X-ray multilayer film reflecting a desired wavelength is formed on the surface of the substrate to form a multilayer mirror. One to many such mirrors are collected and soft X
An optical system for lines is configured.

[0006]

As described above, aspherical surface processing is more difficult than spherical surface processing, and the processing time is extremely long. In particular, when used in the soft X-ray region, strict values are required for the shape accuracy of the aspherical surface. If the target shape accuracy is not achieved in the processed substrate, aberration occurs in the optical system, and the EUVL resolution is reduced.

Further, not only the aspherical shape but also the roughness of the substrate surface is required to be small. If the roughness is large, the scattering amount of soft X-rays increases, and the reflectance of the multilayer mirror decreases. A decrease in the reflectivity lowers the transmittance of the entire optical system, and when used in EUVL, the throughput is undesirably reduced.

[0008] A multilayer mirror for reflecting soft X-rays from a substrate which satisfies strict requirements for shape and roughness is manufactured. In general, a sputtering method is often used for manufacturing a multilayer mirror. That is, a multilayer mirror is manufactured by forming a multilayer film on a non-spherical surface of a substrate by a sputtering method. In order to obtain high reflectivity at the target wavelength over the entire reflecting surface, both the thickness distribution of the multilayer film in the reflecting surface according to the design incident angle distribution and the period length according to the target wavelength must be satisfied at the same time. Must. For this reason, various developments have been made on these control methods.

However, the allowable value of the deviation from the target value of the film thickness distribution and the cycle length is very strict, about 0.1%. Therefore, a multilayer film is formed on the substrate within the allowable value of the deviation. It is very difficult. Therefore, the film thickness distribution and the cycle length of the multilayer film formed on the substrate may not fall within the target range. In this case, the multilayer film is separated from the substrate, and the multilayer film is formed on the substrate again.

As a method of peeling a multilayer film from a substrate,
Generally, a dry etching method or the like is used, but a slight over-etching must be performed to completely remove the multilayer film. Therefore, when the multilayer film is peeled from the substrate, the substrate surface is roughened by over-etching. Therefore, in order to use the substrate again for the soft X-ray optical system, the substrate surface needs to be polished again.

As described above, the aspherical substrate used for the multilayer mirror used in the soft X-ray region has very strict requirements for its shape and roughness, and it is difficult to process the substrate into an aspherical surface. , Which are more expensive than spherical mirrors. In addition, there are strict requirements on the multilayer film formed after the substrate is polished into an aspherical surface, such as shape accuracy. Therefore, when the multilayer film formed on the substrate does not satisfy the required accuracy, the multilayer film is peeled off from the substrate and re-formed. However, since the substrate surface is roughened by over-etching when the multilayer film is peeled off, the substrate needs to be polished again. Therefore, it greatly affects the cost and throughput of manufacturing the multilayer reflector.

The present invention has been made in view of the above circumstances, and has as its object to provide a multilayer reflector capable of peeling a multilayer film without damaging a substrate surface, a method of peeling a multilayer film, and exposure. It is to provide a device.

[0013]

In order to solve the above problems, a multilayer reflector according to the present invention comprises a substrate, an electrode layer formed on the substrate and made of a chemically stable substance,
A dissolving layer formed on the electrode layer and made of a substance having a lower oxidation-reduction potential than the electrode layer; and a difference between the refractive index in the soft X-ray region and the refractive index in a vacuum formed on the dissolving layer is small. A multi-layer film in which a first layer of a substance and a second layer of a large substance are alternately stacked.

According to the multilayer reflector, when the multilayer film is formed again on the substrate, the electrode layer and the dissolution layer are formed between the substrate and the multilayer film. By dissolving, the multilayer film together with the dissolution layer can be peeled from the substrate. Since the electrolysis method is used, the multilayer film can be separated from the substrate without damaging the substrate. Then, even after the multilayer film is peeled, the substrate shape and the roughness can be maintained at the same level as before the multilayer film was peeled, so that it is not necessary to re-polish the substrate surface.

In the multilayer mirror according to the present invention, it is preferable that the electrode layer is made of a substance whose standard oxidation-reduction potential is larger than 0V. Thus, the circuit is cut off at the end of the electrolysis, so that the electrolysis can be performed completely and without loss of time.

Further, in the multilayer mirror according to the present invention, it is preferable that the dissolving layer is made of a substance whose standard oxidation-reduction potential is smaller than 0V. This makes it difficult for hydrogen ions in the electrolytic solution to be reduced when the dissolved layer is decomposed, so that the efficiency of electrolysis can be increased.

In the multilayer mirror according to the present invention, the electrode layer is formed of one selected from the group consisting of gold, silver, platinum, copper, iridium, palladium, rhodium, ruthenium, and these compounds. Preferably, it consists of a substance. Since these substances have good conductivity and are chemically stable, they can be easily formed by a sputtering method or the like.

The method for stripping a multilayer film according to the present invention comprises a substrate, an electrode layer formed on the substrate and made of a chemically stable substance, and an electrode layer formed on the electrode layer and formed on the electrode layer. A dissolving layer formed of a substance having a low oxidation-reduction potential, a first layer of a substance formed on the dissolving layer and having a small difference between a refractive index in a soft X-ray region and a refractive index in a vacuum, and a second layer of a large substance. Prepare a multilayer reflector having a multilayer film, which is alternately laminated, and immerse the multilayer reflector in an electrolytic solution tank,
The separately prepared electrode substrate is immersed in an electrolytic solution tank, and a negative voltage is applied to the electrode substrate and a positive voltage is applied to the electrode layer to remove the dissolved layer by an electrolytic method. Is separated from the substrate and the electrode layer.

An exposure apparatus according to the present invention comprises an X-ray light source for generating X-rays, an illumination optical system for guiding the X-rays from the X-ray light source to a mask, and an X-ray from the mask to a photosensitive substrate. An exposure apparatus having a projection optical system and transferring the pattern of the mask onto a photosensitive substrate, wherein the illumination optical system, at least one of the mask and the projection optical system has a multilayer reflector. The multilayer reflector is composed of a substrate, an electrode layer formed on the substrate and made of a chemically stable substance, and a substance formed on the electrode layer and having a lower oxidation-reduction potential than the electrode layer. And a second layer of a substance formed on the dissolution layer and having a small difference between the refractive index in the soft X-ray region and the refractive index of vacuum in a soft X-ray region and a second layer of a large substance. And a film.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a multilayer reflector according to an embodiment of the present invention.

As shown in FIG. 1, the multilayer reflector 40 has a substrate 41 made of glass, and this substrate 41 has a concave surface and an aspheric surface. On the surface of the substrate 41, an electrode layer 42 made of a chemically stable substance is formed. A dissolution layer 43 made of a substance having a lower oxidation-reduction potential than the electrode layer 42 is formed on the electrode layer 42.
On the dissolution layer 43, a multilayer film 44 is formed. The multilayer film 44 is formed by alternately stacking a first layer of a substance having a small difference between a refractive index in a soft X-ray region and a refractive index of vacuum and a second layer of a large substance.

FIG. 2 is a configuration diagram for explaining a method of peeling a multilayer film according to an embodiment of the present invention.

A multilayer reflector 40 as shown in FIG. 1 is prepared. That is, after the polishing and cleaning operations of the substrate 41 are completed and before the multilayer film 44 is formed, the electrode layer 42 made of a chemically stable substance is formed on the substrate 41, and the electrode layer 42 is more oxidized and reduced than the electrode layer 42. A dissolution layer 43 of a substance having a low potential is formed, and then a multilayer film 44 is formed on the dissolution layer 43. Here, the electrode layer 42 is formed to be partly larger than the dissolution layer 43 and the multilayer film 44 at the outer peripheral portion (portion A) of the surface of the substrate 41. Thus, a part of the electrode layer 42 is exposed even after the formation of the multilayer film 44.

Next, the shape accuracy, film thickness distribution, cycle length and the like of the multilayer mirror 40 are inspected. If the inspection result does not satisfy the shape accuracy required for use in the soft X-ray region, the substrate 41
It is necessary to peel off the substrate 4 and form the multilayer film 44 on the substrate 41 again.

In this case, as shown in FIG.
An electrolytic solution tank 51 and a DC power supply 54 containing 2 are prepared. Then, the plus side of the DC power supply 54 is connected to the electrode layer 42 with the portion A of the multilayer film reflecting mirror 40 as a contact, and the separately prepared electrode substrate 53 is connected to the minus side of the DC power supply 54. Next, the multilayer reflector 40 and the electrode substrate 53 are immersed in the electrolytic solution in the electrolytic solution tank 51, and a voltage is applied between the electrode substrate 53 and the electrode layer 42. The voltage at this time is set to a value lower than the oxidation-reduction potential of the electrode layer 42 and higher than the oxidation-reduction potential of the dissolved layer. As a result, the dissolved layer 43 is electrolyzed and melted from the edge portion of the multilayer film 44, and the multilayer film 44 can be separated from the substrate 41 and the electrode layer 42. Next, a dissolution layer 43 is formed on the electrode layer 42 again, and a multilayer film 44 is formed on the dissolution layer 43.

As the material constituting the electrode layer 2, it is preferable to use a material having a standard electrode potential higher than 0V. This will break the circuit at the end of electrolysis,
Electrolysis can be performed completely and without loss of time. Specific examples of the substance constituting the electrode layer 2 include gold,
Examples thereof include silver, platinum, copper, iridium, palladium, rhodium, ruthenium, and compounds thereof, which are preferable because they have good conductivity, are chemically stable, and can be easily formed by a sputtering method or the like.

It is preferable to use a substance having a standard electrode potential lower than 0 V as a substance constituting the dissolving layer 43. For example, Zn, Fe, Ni and the like are preferable. This is preferable because the reduction of hydrogen ions in the electrolytic solution 52 when the dissolving layer 43 is decomposed hardly occurs, and the efficiency of electrolysis increases.

Further, the electrolytic solution 52 is selected depending on the structure of the multilayer film 44 to be peeled off and the substance used for the dissolution layer 43. In other words, the electrolytic solution 52 is
It is preferable that the composition be such that there is no influence on the dissolution layer 43 and that the dissolution layer 43 can be easily electrolyzed.

According to the above embodiment, when the multi-layer film 44 is formed again on the substrate 41, the electrode layer 42 and the dissolution layer 43 are formed between the substrate 41 and the multi-layer film 44. By dissolving the dissolving layer 43 by the method, the multilayer film 44 can be separated from the substrate 41 together with the dissolving layer 43. Since the electrolysis method is used, the multilayer film can be separated from the substrate without damaging the substrate. That is, it is possible to suppress the substrate surface from being roughened as in the conventional peeling method. Therefore, even after the multilayer film is peeled, the substrate shape and the roughness can be maintained at the same level as before the multilayer film was peeled, so that the substrate surface does not need to be polished. Therefore, in the production of the multilayer reflector, the recycling of the substrate is easier than in the conventional multilayer reflector, and the production cost and throughput of the multilayer reflector can be increased.

The present invention is not limited to the above-described embodiment, but can be implemented with various modifications.

In the above-described embodiment, the surface of the substrate 41 is made aspherical. However, the substrate is not limited to this. It is also possible to use a shape, for example, a spherical surface, a flat surface, or the like. That is, the multilayer film can be easily separated from the substrate surface by using the present invention regardless of the shape of the substrate surface.

FIG. 3 is an overall configuration diagram showing an X-ray exposure apparatus using the multilayer reflector shown in FIG. This X-ray exposure apparatus is a projection exposure apparatus that performs an exposure operation by a step-and-scan method using light in a soft X-ray region near a wavelength of 13 nm (hereinafter, referred to as EUV light) as illumination light for exposure.

At the most upstream part of the X-ray exposure apparatus 1, a pulse laser light source 3 is provided. The laser light source 3 has a function of supplying laser light of any one of infrared, visible, and ultraviolet wavelengths. For example, a YAG laser or an excimer laser excited by a semiconductor laser is used. The laser light emitted from the laser light source 3 is condensed by the condensing optical system 5 and reaches the plasma generator 7 arranged below.

A nozzle (not shown) is arranged in the plasma generating section 7 and ejects xenon gas. The jetted xenon gas receives a high illuminance laser beam in the plasma generating section 7. The xenon gas is excited into a plasma state by the energy of the high-intensity laser light, and emits EUV light when transitioning to a low potential state. Since EUV light is absorbed by the atmosphere, its optical path is covered by a chamber (vacuum chamber) 9 to block outside air.

On the upper part of the plasma generator 7, Mo / Si
A rotating parabolic reflecting mirror 11 coated with a multilayer film is arranged. The X-rays radiated from the plasma generator 7 are incident on the parabolic reflector 11, and only X-rays having a wavelength of about 13 nm are reflected in parallel downward from the exposure apparatus 1.

A visible light cut X-ray transmission filter 13 made of Zr (zirconium) having a thickness of 0.15 nm is disposed below the paraboloid of reflection mirror 11. Desired 13 nm of X-rays reflected by the paraboloid of revolution 11
Only the X-rays passing through the transmission filter 13. The vicinity of the transmission filter 13 is covered by the chamber 15 to block outside air.

Below the transmission filter 13, a wafer chamber 33 is provided. An illumination optical system 17 is arranged below the transmission filter 13 in the wafer chamber 33. The illumination optical system 17 includes a condenser-type reflecting mirror, a fly-eye optical-system reflecting mirror, and the like, shapes the X-rays input from the transmission filter 13 into an arc shape, and irradiates the X-rays toward the left in the drawing. I do.

An X-ray reflecting mirror 19 is arranged on the left side of the illumination optical system 17 in the drawing. The X-ray reflecting mirror 19 is a circular rotating parabolic mirror having a concave reflecting surface 19a on the right side in the figure, and is vertically held by a holding member. The X-ray reflecting mirror 19 is made of a quartz substrate whose reflecting surface 19a is processed with high precision. On the reflection surface 19a, a multilayer film of Mo and Si having a high thermal conductivity and a high reflectance of X-rays having a wavelength of 13 nm is formed. When X-rays having a wavelength of 10 to 15 nm are used, Ru (ruthenium), Rh (rhodium)
And a material such as Si, Be (beryllium), B4C (carbon tetraboride), or the like.

On the right side of the X-ray reflecting mirror 19 in the figure, an optical path bending reflecting mirror 21 is disposed obliquely. Above the optical path bending reflection mirror 21, a reflection type mask 23 is horizontally disposed so that the reflection surface faces down. Illumination optical system 17
Are reflected and condensed by the X-ray reflecting mirror 19 and then reach the reflecting surface of the reflective mask 23 via the optical path bending reflecting mirror 21.

A reflection film made of a multilayer film is also formed on the reflection surface of the reflection type mask 23. A mask pattern corresponding to the pattern to be transferred to the wafer 29 is formed on the reflection film. The reflective mask 23 is fixed to a mask stage 25 illustrated above the mask. The mask stage 25 is movable in at least the Y direction, and sequentially irradiates the mask 23 with the X-rays reflected by the optical path bending reflecting mirror 21.

Below the reflective mask 23, a projection optical system 27 and a wafer 29 are arranged in this order. Projection optical system 2
Reference numeral 7 denotes a plurality of reflecting mirrors and the like, which reduces the X-rays reflected by the reflective mask 23 to a predetermined reduction magnification (for example, 1/4) and forms an image on the wafer 29. The wafer 29 is fixed to the wafer stage 31 movable in the XYZ directions by suction or the like.

The gate valve 35 is provided in the wafer chamber 33.
, A preliminary exhaust chamber (load lock chamber) 37 is provided. A vacuum pump 39 is connected to the preliminary exhaust chamber 37, and the preliminary exhaust chamber 37 is evacuated by operating the vacuum pump 39.

When performing the exposure operation, the illumination optical system 17 irradiates the reflective surface of the reflective mask 23 with EUV light.
At this time, the reflective mask 23 and the wafer 29 are relatively synchronously scanned with respect to the projection optical system 27 at a predetermined speed ratio determined by the reduction magnification of the projection optical system. As a result, the entire circuit pattern of the reflective mask 23 is transferred to each of the plurality of shot areas on the wafer 29 by the step-and-scan method. The chips of the wafer 29 are, for example, 25 × 25.
mm square, 0.07 μmL / S IC on resist
The pattern can be exposed.

The multilayer mirror 40 shown in FIG. 1 is arranged in at least one of the illumination optical system, the mask and the projection optical system.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0046]

First Embodiment A first embodiment according to the present invention will be described with reference to FIGS. As shown in FIG.
A substrate 41 made of quartz glass (flat) having a thickness of 0 mm is prepared, and an electrode layer 42 made of a single-layer Pt film having a thickness of about 50 nm is formed on the surface of the substrate 41 in a range of φ98 mm by an ion beam sputtering method. .

Next, a dissolution layer 4 made of a Cu single layer film having a thickness of about 100 nm is formed on the electrode layer 42 in a range of φ90 mm.
3 and a Mo / Si multilayer film 44 is formed on the dissolution layer 43 by a sputtering method. These film formation ranges are performed by shielding the edge portion of the substrate with the substrate holder. The Mo / Si multilayer film 44 has a 50-layer number,
The cycle length is 6.9 nm, and the film thickness ratio (= Mo layer thickness / cycle length) is 0.35.

After that, the shape accuracy, the film thickness distribution, the period length, and the like of the multilayer film reflecting mirror 40 are inspected. If the inspection result does not satisfy the shape accuracy and the like required when used in the soft X-ray region, the multilayer film 44 is separated from the substrate 41 by the method shown in FIG.

That is, a Pt plate 53 is connected to the cathode side of the DC power supply 54, and the electrode layer 42 of the multilayer mirror 40 is connected to the anode side using an approximately 10% NaCl aqueous solution for the electrolyte 52 in the electrolyte bath 51. Connecting. When the dissolving layer 43 is electrolyzed using an apparatus as shown in FIG. 2, the multilayer film 44 starts to peel off gradually from the edge portion, and the applied voltage sharply increases.
The dissolution of the dissolving layer 43 ends. Only the substrate 41 and the electrode layer 42 are left on the anode side. After the electrolysis, the substrate 41 is washed with pure water, and then washed and dried with IPA.

When the shape and roughness of the substrate obtained by the above steps were measured using an interferometer, the shape was almost the same as before the multilayer film was peeled off, and the shape change was within an error. Before and after peeling, the RMS was 0.3 nm.

[0051]

Second Embodiment A second embodiment according to the present invention will be described with reference to FIGS. As shown in FIG.
A substrate 41 made of 0 mm Si (convex aspherical surface) is prepared,
On the surface of the substrate 41, an Au having a thickness of about 50 nm was formed in a range of φ98 mm by an ion beam sputtering method.
An electrode layer made of a single-layer film is formed.

Next, a dissolution layer 4 made of a Zn single-layer film having a thickness of about 100 nm is formed on the electrode layer 42 in a range of φ90 mm.
3 and a Mo / Si multilayer film 44 is formed on the dissolution layer 43 by a sputtering method. These film formation ranges are performed by shielding the edge portion of the substrate with the substrate holder. The Mo / Si multilayer film 44 has a 50-layer number,
The cycle length is 6.9 nm, and the film thickness ratio (= Mo layer thickness / cycle length) is 0.35.

Thereafter, the shape accuracy, the film thickness distribution, the period length, etc. of the multilayer film reflecting mirror 40 are inspected. If the inspection result does not satisfy the shape accuracy and the like required when used in the soft X-ray region, the multilayer film 44 is separated from the substrate 41 by the method shown in FIG.

That is, an approximately 150 g / l NH ₄ Cl aqueous solution was used for the electrolytic solution 52 in the electrolytic solution tank 51, and a DC power supply 5 was used.
4, the Pt plate 53 is connected to the cathode side, and the electrode layer 42 of the multilayer reflector 40 is connected to the anode side. When the dissolving layer 43 is electrolyzed by using an apparatus as shown in FIG. 2, the multilayer film 44 gradually starts peeling from the edge portion, and the dissolution of the dissolving layer 43 ends with an abrupt increase in applied voltage. Only the substrate 41 and the electrode layer 42 are left on the anode side. After the electrolysis, the substrate 41 is washed with pure water, and then washed and dried with IPA.

When the shape and roughness of the substrate obtained by the above steps were measured using an interferometer, the shape was almost the same as before the multilayer film was peeled, the shape change was within an error, and the roughness was the multilayer film peeling. Both before and after peeling, the RMS was 0.2 nm.

[0056]

As described above, according to the present invention, an electrode layer and a dissolution layer are formed between a substrate and a multilayer film.
Therefore, it is possible to provide a multilayer mirror, a multilayer film removing method, and an exposure apparatus capable of removing a multilayer film without damaging the substrate surface.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a multilayer mirror according to an embodiment of the present invention.

FIG. 2 is a configuration diagram for explaining a multilayer film peeling method according to an embodiment of the present invention.

FIG. 3 is an overall configuration diagram showing an X-ray exposure apparatus using the multilayer mirror shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... X-ray exposure apparatus 3 ... Laser light source 5 ... Condensing optical system 7 ... Plasma generation part 9 ... Chamber 11 ... Rotating parabolic reflective mirror 13 ... X-ray transmission filter 15 ... Chamber 17 ... Illumination optical system 19 ... X-ray Reflecting mirror 19a Reflecting surface 21 Optical path bending reflecting mirror 23 Reflective mask 25 Mask stage 27 Projection optical system 29 Wafer 31 Wafer stage 33 Wafer chamber 35 Gate valve 37 Preliminary exhaust chamber (load lock chamber) Reference numeral 39: vacuum pump 40: multilayer reflector 41: substrate 42: electrode layer 43: dissolving layer 44: multilayer 51: electrolytic solution tank 52: electrolytic solution 53: electrode substrate 54: DC power supply

Claims (6)

[Claims] 1. A substrate, an electrode layer formed on the substrate and made of a chemically stable substance, and a solution formed on the electrode layer and made of a substance having a lower oxidation-reduction potential than the electrode layer. A multilayer film formed on the dissolving layer, wherein a first layer of a substance having a small difference between a refractive index in a soft X-ray region and a refractive index of vacuum and a second layer of a large substance are alternately laminated; A multilayer reflector comprising: 2. The electrode layer according to claim 1, wherein the standard oxidation-reduction potential is greater than 0V.
2. The multilayer mirror according to claim 1. 3. The dissolving layer is made of a substance whose standard redox potential is smaller than 0V.
2. The multilayer mirror according to claim 1. 4. The electrode layer is made of gold, silver, platinum, copper,
The multilayer mirror according to claim 1, comprising a substance using one selected from the group consisting of iridium, palladium, rhodium, ruthenium, and these compounds. 5. A substrate, an electrode layer formed on the substrate and made of a chemically stable substance, and a solution formed on the electrode layer and made of a substance having a lower oxidation-reduction potential than the electrode layer. A multilayer film formed on the dissolving layer and having a first layer of a substance having a small difference between a refractive index in a soft X-ray region and a refractive index of vacuum and a second layer of a large substance alternately laminated; Prepare a multilayer reflector provided with: and, immerse the multilayer reflector in an electrolytic solution tank, immerse a separately prepared electrode substrate in the electrolytic solution tank, and apply a negative voltage to the electrode substrate. A multilayer film peeling method, wherein the multilayer film is peeled from a substrate and an electrode layer by applying a positive voltage to the electrode layer and removing the dissolved layer by an electrolysis method. 6. An X-ray light source for generating X-rays, an illumination optical system for guiding X-rays from the X-ray light source to a mask, and a projection optical system for guiding X-rays from the mask to a photosensitive substrate. And
In an exposure apparatus for transferring the pattern of the mask onto a photosensitive substrate, at least one of the illumination optical system, the mask and the projection optical system has a multilayer reflector, and the multilayer reflector is a substrate. An electrode layer formed on the substrate and made of a chemically stable substance, a dissolution layer formed on the electrode layer and made of a substance having a lower oxidation-reduction potential than the electrode layer, and a dissolution layer A multi-layered film formed on the first layer, wherein a first layer of a substance having a small difference between a refractive index in a soft X-ray region and a refractive index of a vacuum and a second layer of a large substance are alternately laminated. An exposure apparatus, comprising: