JP2000088999A - X-ray device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray device capable of removing a substance adhering on a surface in disposition as it is without taking out a soft X-ray optical element from a vacuum vessel. SOLUTION: When a multi-layer film reflection mirror 102 and a mask 104 are arranged in a vacuum vessel 112 for a long time, a carbon contaminant adheres on a surface by the cause of oil or the like slightly reversely flowing from an exhaust system or the like. The carbon contaminant remarkably lowers the reflectance of an X-ray. After a certain period elapses, irradiation with beams of KrF excimer laser light 106, 107 is performed. During the irradiation of the pieces of the KrF excimer laser light 106, 107, oxygen not exceeding 100 Pa is introduced in the vacuum vessel 112. When the beams of the KrF excimer laser light 106, 107 enter the state where oxygen exists in the circumference, carbon forming the carbon contaminant is excited to react with oxygen so as to be carbon dioxide. Thereby the carbon contaminant is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray
The present invention relates to an X-ray apparatus such as an X-ray microscope and an X-ray analyzer, and more specifically, a substance adhering to the surface of a soft X-ray optical element without removing the soft X-ray optical element from a vacuum vessel and keeping the same arrangement. The present invention relates to an X-ray apparatus capable of removing the odor.

[0002]

2. Description of the Related Art At present, reduced projection exposure using light is widely used for manufacturing a semiconductor integrated circuit having a fine pattern of the semiconductor integrated circuit. The wavelength of light used for reduction exposure has been shortened with the miniaturization of patterns, but in the future, soft X-rays will be used to form fine patterns that are in principle impossible with visible and ultraviolet light. Attempts have been made.

In the soft X-ray region having a wavelength of 1 to 100 nm, since all substances have strong absorption, there is no transmission type optical element utilizing refraction as in the visible light region. Is used as an optical element. Above all, the direct-incidence reflectance is around 11 nm and 13 nm.
A multilayer mirror capable of obtaining a reflectance of about 70% has been manufactured, and a reduction projection exposure apparatus using a reflective optical system using the multilayer film has been proposed.

When using a thin film filter or a multilayer film,
In the soft X-ray region, since all substances have strong absorption, dirt adhering to the surface is a serious problem. If there is a sliding portion on the sample stage or the like, fine particles may be generated and adhere to the soft X-ray optical element. Also, since soft X-rays are absorbed by air, it is necessary to evacuate the optical path to a vacuum. However, very little oil or the like flows backward from the normal exhaust system. Then, dirt called carbon contamination adheres to the surface of the soft X-ray optical element, and reduces the transmittance and the reflectance of the soft X-ray. Also, X
In a line exposure apparatus, a wafer coated with a photosensitive polymer called a resist at the time of exposure is carried into a vacuum vessel, and a trace amount of gas generated from the resist may cause carbon contamination.

When a pulse laser beam (an example of an excitation energy beam) is condensed and irradiated on a target member placed in a reduced-pressure vacuum vessel, the target member rapidly turns into plasma,
Extremely bright X-rays radiate (emit) from this plasma
(Generating X-rays). An X-ray source that generates X-rays by generating plasma in this manner is referred to as a laser plasma X-ray source (LPX). In a laser plasma X-ray source, scattered particles such as high-speed ions and electrons from the plasma together with X-rays, and scattered particles of a member (for example, gasified material,
Ionized material, material pieces, etc.) are released and scattered in the vacuum vessel. In an X-ray apparatus using a laser plasma X-ray source as an X-ray source, these scattered particles adhere to the surface of the soft X-ray optical element, which causes a problem. is there.

The most commonly used method for cleaning the surface of a substance at present is a wet cleaning method combining treatment with a chemical solution and rinsing with pure water. This cleaning method
It is very widely used in the manufacturing process of semiconductor integrated circuits and the like, and has responded to the removal of finer deposits by increasing the purity and cleanliness of chemicals and pure water. However, there is a problem in that a large amount of a chemical solution and pure water are consumed, and in recent years, other cleaning methods such as spraying fine water droplets at an ultra-high speed or irradiating pulse light have been proposed.

[0007] The latter method of irradiating pulse light is effective when light having a wavelength that is strongly absorbed by the attached matter or the substrate is used. If only the surface is rapidly heated by the pulsed light, only that part expands, but if heating occurs in a short time with the pulsed light, the displacement acceleration is very large, so the fine particles attached to the surface are removed. It is said to lead. In addition, when a thin film-like deposit is formed on the surface, when pulsed light is applied, peeling occurs instantaneously due to a difference in physical characteristics (such as coefficient of thermal expansion) from the base, which is different from the case of fine particles. It is also said to lead to removal. When the deposit is an organic substance containing carbon as a main component, the deposit can be removed by irradiating ultraviolet light in an appropriate oxygen atmosphere. In this case, the bond between carbon atoms in the deposit is broken by ultraviolet light, and the carbon bonds with oxygen to form carbon dioxide and is removed.

[0008]

However, the possibility that any substance adheres to the surface of the soft X-ray optical element placed in a vacuum cannot be completely eliminated. However, the soft X-ray optical system is very sensitive to surface dirt,
Although it is necessary to remove a substance attached to the line optical element, it is impossible to perform the cleaning in a vacuum by the currently most commonly used wet cleaning method. Therefore, in order to perform cleaning, it is necessary to take out the soft X-ray optical element arranged in a vacuum from the vacuum vessel, arrange it again after cleaning, and perform strict alignment, but this takes a long time, which is desirable. is not. For these reasons, there has been a demand for a technique for removing a substance adhering to the surface of a soft X-ray optical element without removing the substance from the vacuum vessel and keeping the same arrangement.

The present invention has been made in view of such circumstances, and provides an X-ray apparatus capable of removing a substance adhering to a surface without removing a soft X-ray optical element from a vacuum vessel and keeping the same arrangement. The task is to

[0010]

A first means for solving the above problems is to extract an X-ray having a wavelength to be used from an X-ray generating section and an X-ray generated from the X-ray generating section. An X-ray apparatus provided with an X-ray optical system unit for changing a light beam suitable for a purpose of use, wherein a mechanism for irradiating a pulsed energy beam on a surface of an X-ray optical element included in the X-ray apparatus is provided. An X-ray apparatus (claim 1).

When a pulse-like energy beam is incident on the surface of an X-ray optical element, fine particles adhering to the surface of the X-ray optical element and a thin film formed on the surface receive energy from the energy beam and become hot. Rises and expands rapidly to excite the movement. Since the incident energy beam has a pulse shape, this expansion occurs rapidly, and the acceleration of the motion displacement becomes very large. Therefore, by this movement, the fine particles attached to the surface of the X-ray optical element and the thin film formed on the surface are removed from the surface of the X-ray optical element.

A typical energy beam is:
Excimer laser emission light is mentioned. Which X-ray optical element the energy beam is incident on may be determined as appropriate according to the degree of contamination of each element, the degree of influence of contamination on the optical system, and the like. It is not necessary to make an energy beam incident.

[0013] A second means for solving the above-mentioned problems is as follows.
The first means, wherein a pulse width of the energy beam is 1 microsecond or less (claim 2).

By making the pulse width of the energy beam as short as 1 microsecond or less, the movement displacement of the substances attached to the surface of the X-ray optical element is made large enough to reliably remove these substances. Can be.

[0015] A third means for solving the above problems is as follows.
The first means or the second means, wherein the energy density per unit area of the pulsed energy beam incident on the surface of the X-ray optical element is variable (Claim 3). It is.

By making the energy density per unit area of the energy beam variable, it is possible to obtain the optimum intensity according to the properties of the particles attached to the surface of the X-ray optical element and the properties of the thin film formed on the surface. An energy beam can be irradiated.

A fourth means for solving the above-mentioned problem is:
Any one of the first to third means, wherein X
The irradiation position of the pulse-like energy beam incident on the surface of the X-ray optical element on the surface of the X-ray optical element is variable (claim 4).

According to this means, it is possible to monitor the status of the dirt on the X-ray optical element and to irradiate the energy beam concentratedly on the heavily contaminated portion, so that the dirt can be efficiently removed. In addition, the energy beam is narrowed down, the intensity is increased by that amount, and scanning is performed by changing the irradiated portion, whereby it is possible to remove stains and the like from a large area.

A fifth means for solving the above-mentioned problem is:
In the first means to the fourth means, in the reflecting mirror having a multilayer structure among the X-ray optical elements, the multilayer film can obtain a sufficient reflectance for the X-rays to be used. The present invention is characterized in that the number of layers is larger than the number of layers (claim 5).

When it is intended to remove fine particles and the like adhering to the surface by irradiating a pulse energy beam, depending on the conditions, a very small amount of the underlying substance may be removed by the pulse energy beam irradiation. In such a case, if the underlayer has a multilayer structure for the purpose of obtaining a high reflectance with soft X-rays, the reflectance may decrease due to a decrease in the number of layers. However, according to the present means, even if the uppermost layer portion of the underlying multilayer film is slightly removed, a sufficient number of films remain to obtain a high reflectance. Can be.

A sixth means for solving the above-mentioned problems is any one of the first means to the fifth means, wherein the reflection mirror having a multilayer structure among the X-ray optical elements is provided. Is characterized in that, of the materials forming the multilayer film, the material layer having the smaller X-ray absorption coefficient is the uppermost layer, and the uppermost layer is thicker than the portion forming the periodic structure. 6).

According to this means, even if the uppermost layer portion of the multilayer film is slightly removed by the irradiation of the pulse energy beam, the uppermost layer is thicker than the periodic structure portion. Has little effect and can maintain high reflectance. In addition, since the uppermost portion having a large film thickness is a material having a smaller X-ray absorption coefficient, a decrease in soft X-ray reflectivity can be suppressed low.

A seventh means for solving the above problem is as follows.
In any one of the first means to the sixth means, an inert gas is introduced into the vacuum vessel during pulsed energy beam irradiation (claim 7).

The substance (fine particles, etc.) removed by irradiating a pulsed energy beam may scatter around and adhere to the surface of another soft X-ray optical element or the like, thereby deteriorating its optical characteristics. There is. According to this means, the removed substance is scattered by the introduced inert gas molecules and loses momentum, so that it can be prevented from reaching another soft X-ray optical element or the like. The optical performance of the device can be maintained.

Eighth means for solving the above-mentioned problem is:
In any one of the first to seventh means, the irradiation target X at the time of pulsed energy beam irradiation.
According to another aspect of the present invention, there is provided a shielding device capable of covering a surface of an element other than the linear optical element.

According to this means, when the X-ray optical element is irradiated with the pulse laser beam to remove the fine particles, it is possible to prevent the fine particles from re-adhering to the surface of another element. In addition, it is possible to prevent the reflected light of the irradiated pulse light from irradiating unexpected portions, and to prevent these portions from being damaged or deteriorated.

A ninth means for solving the above-mentioned problem is:
In any one of the first to eighth means, when irradiating a pulsed energy beam, introducing a gas containing at least one of oxygen and ozone, or at least one of them, into the vacuum vessel. (Claim 9).

By introducing these gases, carbon excited by the energy beam is combined with oxygen and easily removed as carbon dioxide. The generated carbon dioxide is carried out of the X-ray generator together with the introduced gas.

A tenth means for solving the above-mentioned problem is any one of the first to ninth means, wherein the X-ray optical element to be irradiated at the time of pulsed energy beam irradiation is used. A mechanism for supplying water to the surface is provided (claim 10).

When removing fine particles adhering to the surface, it is more effective if a thin film such as water is present on the surface. Therefore, in this means, water is supplied to the surface by spraying, dew condensation, or the like.

[0031] An eleventh means for solving the above-mentioned problem is that, in any of the first means or the third to tenth means, a continuous ultraviolet beam is used instead of a pulsed energy beam. It is characterized in that it has been used (claim 11).

In the case where ultraviolet rays are used as the energy beam, it is possible to remove foreign substances adhering to the surface and a thin film formed on the surface even if the energy beam is not pulsed but is continuously irradiated on the X-ray optical element. it can. Ultraviolet irradiation is particularly effective in removing carbon contamination.

A twelfth means for solving the above-mentioned problem is either the ninth means or the eleventh means, wherein the soft X-ray optical element is housed in a container and the container is sealed or sealed. It can be substantially sealed, and at the time of soft X-ray irradiation, a mechanism for moving the portion of the container that blocks the soft X-ray optical path out of the optical path, and a pulse-like structure on the surface of the soft X-ray optical element when the container is sealed or substantially closed. A transmission window capable of irradiating an energy beam or ultraviolet light and a gas introduction mechanism for introducing oxygen or ozone gas into a closed or substantially closed container are provided (claim 12).

When an ultraviolet ray is irradiated in an oxygen or ozone atmosphere to excite carbon and oxygen or ozone in the carbon contamination to react them and remove them as carbon dioxide, an optical path through which the ultraviolet ray passes through the oxygen or ozone. If the pressure of oxygen or ozone is too low for the transmission of ultraviolet rays, the density of active oxygen atoms may be too low and a sufficient reaction rate may not be obtained. According to this means, at the time of irradiation with a pulsed energy beam or ultraviolet light, the vessel containing the soft X-ray optical element is sealed, oxygen or ozone is introduced therein, and the pulsed energy beam or ultraviolet light is irradiated. The UV light is irradiated through a possible transmission window. At this time, since the ultraviolet light path outside the container is evacuated to 0.1 Pa or less or replaced by dry nitrogen, attenuation due to absorption of oxygen in the vacuum container does not cause a problem, and a pulse shape of sufficient intensity is used. Energy beam or ultraviolet light reaches the surface of the soft X-ray optical element. Therefore, sufficient removal of carbon contamination can be sufficiently performed.

A thirteenth means for solving the above-mentioned problem is any one of the first to twelfth means, wherein the X-ray optical element is irradiated with a pulsed energy beam or a continuous ultraviolet beam. (Claim 13).

In this means, the X-ray optical element is irradiated with an energy beam (including an ultraviolet beam).
By heating the X-ray optical element, the foreign matter attached to the surface and the formed thin film are easily peeled off. In particular, when oxygen or ozone is present on the surface of these X-ray optical elements, the reaction with these foreign substances or oxygen in the thin film is promoted.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a part of an X-ray reduction projection exposure apparatus according to a first embodiment of the present invention. In FIG. 1, 101 is an X-ray, 102 is a multilayer mirror, 103 is a mask stage, 104 is a mask,
05 is an X-ray, 106 and 107 are KrF excimer laser beams, 108 and 109 are windows, 110 and 111 are reflecting mirrors,
12 is a vacuum container.

X-ray 1 extracted from an X-ray source (not shown)
Reference numeral 01 denotes a mask 104 mounted on a mask stage 103 via a multilayer reflector 102 constituting an illumination optical system.
To illuminate. The X-ray 105 reflected by the mask 104 travels to a projection optical system (not shown) for reducing and projecting the pattern on the mask. These optical systems are arranged in a vacuum vessel 112 capable of evacuating to a pressure of 1 Pa or less.

On the surfaces of the multilayer film reflecting mirror 102 and the mask 104, a KrF excimer laser beam 10
6, 107 can be illuminated through windows 108, 109. The irradiation intensity is variable and the reflector 1
By moving 10, 111, the irradiation position is also variable. Further, oxygen gas having a pressure of 100 Pa or less can be introduced into the vacuum vessel 112.

If the multilayer film reflecting mirror 102 and the mask 104 are placed in the vacuum container 112 for a long time, carbon contamination (carbon contamination) on the surface is caused by oil or the like flowing backward from an exhaust system or the like. Adhere to. Carbon contamination significantly reduces the reflectivity of X-rays. Therefore, after a certain period of time, the surfaces of the multilayer reflector 102 and the mask 104 are exposed to the KrF excimer laser beams 106 and
7 is performed.

At the time of irradiation with the KrF excimer laser beams 106 and 107, oxygen of about 100 Pa is introduced into the vacuum vessel 112. When KrF excimer laser beams 106 and 107 are incident in a state where oxygen is present in the surroundings, carbon forming carbon contamination is excited and combined with oxygen to form carbon dioxide. Thereby, carbon contamination is removed.

Further, when foreign matter such as fine particles adheres to the mask 104, a shadow of the foreign matter is projected, which may cause a defect in exposure. When a pulse-like energy beam is irradiated with such fine particles attached, the temperature of the independent minute foreign matter increases more easily than the main body of the mask 104 having three-dimensional spread, so that the foreign matter rapidly expands and vibrates. Is excited. If the duration of the pulse is short, the expansion is so rapid that the acceleration of the displacement is very large, thereby removing particulates.

FIG. 2 is a schematic configuration diagram of a soft X-ray reduction projection exposure apparatus according to a second embodiment of the present invention. 2, 201 is a vacuum vessel, 202 is an X-ray generator,
203 is a nozzle, 204 is a pulse laser beam, 205 is a lens, 206 is a pulse laser beam introduction window, 207 is plasma, 208 is an X-ray to be used, 209 is a thin film filter, 210 is a multilayer film reflector constituting an illumination optical system. , 21
1 is a mask stage, 212 is a mask, 213 is a reflected X-ray, 214 is a multilayer reflector constituting a projection optical system,
215 is a wafer stage, 216 is a silicon wafer, 2
17 is a pulse laser beam, 218 is a reflecting mirror, 219 is a pulse laser beam, 220 is an introduction window, 221 is a reflecting mirror,
22, 223, 224, 225 are introduction windows, 226, 22
7, 228, 229 are pulse laser beams, 230, 23
1, 232, 233 are reflecting mirrors, 234 is a gas inlet, 2
Reference numeral 35 denotes an exhaust port.

The inside of the vacuum vessel 201 is evacuated by an exhaust device (not shown) so that the pressure is 1 Pa or less so that soft X-rays are not absorbed. In the X-ray generation unit 202, krypton gas is intermittently ejected from the nozzle 203. A pulse laser beam (up to 0.5 J, 10 ns) 204 is condensed by the lens 205 onto the ejected krypton gas, and is irradiated through a pulse laser beam introduction window 206. Plasma 207 is formed at the focusing position, and soft X
Generate a line. The soft X-rays 208 to be used pass through the thin-film filter 209 for extracting X-rays and enter the X-ray optical system.

The X-ray generation section is difficult to evacuate to a high vacuum because of the repeated ejection of krypton gas. However, the X-ray optical system section is used to avoid the effects of contamination of the element and absorption of X-rays. A high vacuum is desirable. Therefore, X
The ray generator and the X-ray optical system are separated by a thin film filter 209 constituting an X-ray extraction window. The soft X-rays 208 incident on the X-ray optical system are reflected by the multilayer reflector 210 constituting the illumination optical system, and illuminate the mask 212 arranged on the mask stage 211.

The mask 212 has a pattern formed of a multilayer film. The pattern of the reflected X-ray 213 on the mask 212 is arranged on the wafer stage 215 by the multilayer film reflecting mirror 214 constituting the projection optical system. Then, the image is reduced and projected on the silicon wafer 216 coated with the resist.

This soft X-ray reduction projection exposure apparatus has many parts whose performance may be reduced due to surface contamination. In the X-ray generation unit 202, dirt adheres to the pulse laser beam introduction window 206 and the side of the thin film filter 209 facing the plasma. When targeting gas,
Since ions or the like forming the plasma are gases, their adhesion does not pose a problem, but since the plasma 207 is formed very close to the outlet of the nozzle 203,
The material constituting the outlet is scraped off by the plasma and scatters and adheres to the surroundings. When such contaminants adhere to the pulsed laser beam introduction window 206, the transmittance is reduced, and the X-ray dose generated by the reduction of the condensing energy is reduced. In addition, when attached to the thin film filter 209, the transmittance of X-rays is reduced.

To remove such dirt, a KrF excimer laser beam is applied. The pulse laser light introduction window 206 is irradiated with KrF excimer laser light 217 from the side opposite to the surface having dirt. This is because, in the case of a transparent material, irradiation from the back surface of dirt tends to obtain a higher removal effect. The irradiation intensity is variable, but irradiation is performed at about 100 mJ / cm ² . By moving the reflecting mirror 218, dirt on the entire surface of the introduction window 206 can be removed.

Since the thin-film filter 209 is not transparent to KrF excimer laser light, irradiation is performed from the side where dirt adheres. That is, KrF excimer laser light 2
19 is introduced into the X-ray generation unit 202 through the introduction window 220, and the reflection mirror 221 is moved to
Irradiation is performed on the entire surface of the substrate 09 to remove the film of the attached substance.

The surfaces of the multilayer mirror 210, the mask 212, and the multilayer mirror 214 are free from the possibility that dirt generated from the X-ray generating portion directly adheres. However, inside the vacuum vessel 201, carbon contamination adheres due to oil slightly flowing backward from the exhaust system or a resist applied to the surface of the wafer 212. Further, there is a possibility that fine particles generated in sliding parts such as the mask stage 211 and the wafer stage 215 may also adhere.

Therefore, the introduction windows 222 and 22 are respectively provided.
KrF excimer laser beams 226, 227, 228, and 229 are introduced through 3, 224, and 225;
0, 231, 232, and 233 are used to irradiate the respective surfaces. Gas inlet 23 during irradiation
Oxygen is introduced from the exhaust port 4 and the pressure of oxygen is controlled to be about 100 Pa by controlling the exhaust speed from the exhaust port 235. When KrF excimer laser light is irradiated in this atmosphere, carbon excited by the ultraviolet pulse light is combined with oxygen, and is removed as carbon dioxide. Further, the fine particles attached to the surface are removed from the surface by rapid heating and expansion by pulsed light irradiation. In the present embodiment, krypton gas is used as the target material for generating X-rays by condensing and irradiating a laser beam, but the target material is not limited to this.

When irradiating a pulse laser beam to the X-ray optical element to remove fine particles, to prevent re-adhesion to the surface of another element, a gap between the X-ray optical element and another element should be used during the pulse laser beam irradiation. It is desirable to arrange a shielding plate that blocks the air. In addition, it is desirable to dispose a reflected light shielding member so that the reflected light of the irradiated pulse light does not irradiate an unexpected portion.

In this embodiment, the pulse light irradiation is performed on the element directly related to the soft X-ray reduction projection exposure. However, other parts where contamination is a problem, such as the window material of the X-ray detector, are also irradiated. It is desirable to be able to perform.

It is more effective to remove fine particles adhering to the surface if a thin film of water or the like is present on the surface. It is desirable that water can be supplied to the surface by such means.

In this embodiment, pulsed light irradiation is performed periodically after a certain period of time. However, when a reflected light or a transmitted light is detected and a decrease of a certain amount or more is observed, Pulse light irradiation may be performed.

In the above embodiment, the KrF excimer laser beam is irradiated to remove carbon contamination. However, in the case of removing carbon contamination, UV lamp irradiation may be used. In this case, it is necessary to control the oxygen pressure in consideration of the absorption by oxygen so that the UV light reaches the surface. In the case where UV light is used, the effect can be obtained even if continuous irradiation is performed without using pulse light. As the ultraviolet light source, ultraviolet light emitted from laser plasma or vacuum ultraviolet light may be used. The laser plasma emits light in a wide wavelength range, such as visible light, ultraviolet light, and vacuum ultraviolet light, in addition to X-rays. Therefore, if these are used, it is not necessary to prepare an additional ultraviolet light source.

FIG. 3 is a schematic configuration diagram showing a part of an X-ray reduction projection exposure apparatus according to a third embodiment of the present invention. In FIG. 3, 301 is a soft X-ray optical element, 301 is a soft X-ray optical element storage container, 303 is a shielding plate, 304 is a gas inlet, 305 is a gas outlet, 306 is a transmission window, and 31
Numeral 0 denotes ultraviolet rays and numeral 311 denotes soft X-rays.

When the soft X-ray 311 is emitted, the shielding plate 303
Is moved to the left as shown by the dotted line in the figure, and the soft X-ray 3
Irradiation to the soft X-ray optical element 301 is not interrupted. When removing scattered particles attached to the soft X-ray optical element 301, the shielding plate 303 is moved to the right,
The soft X-ray optical element storage container 303 is sealed. Then, oxygen or ozone gas is introduced into the soft X-ray optical element storage container 303 through the gas inlet 304, and is discharged through the gas outlet 305. At the same time, the transmission window 306 that transmits ultraviolet light
Irradiates the surface of the soft X-ray optical element 301 with ultraviolet rays 310.

The carbon, oxygen or ozone of the scattered particles adhering to the soft X-ray optical element 301 is
Are excited and reacted by the carbon, and carbon is converted into carbon dioxide and discharged from the exhaust port 305. When the deposit is an organic substance, the ultraviolet light 310 breaks a chain bond of the organic substance,
It also has the effect of making it easier to combine carbon with oxygen or ozone.

In this means, oxygen or ozone gas is introduced only into the soft X-ray optical element storage container 303. Thus, there is no high concentration of oxygen or ozone in other parts of the vacuum vessel. Therefore, the optical path length of the ultraviolet ray 310 passing through oxygen or ozone is shortened, and the ultraviolet ray 310 is not attenuated so much.
Can reach the surface.

In the above embodiments, when the X-ray optical element irradiated with the pulse laser beam is heated, the attached fine particles and the formed thin film are easily peeled off by the influence of the heating, and the oxygen and carbon Is also preferred because it also promotes binding.

[0062]

As described above, according to the first aspect of the present invention, a mechanism for irradiating a pulse-like energy beam on the surface of an X-ray optical element included in an X-ray apparatus is provided. Therefore, without exposing the vacuum optical system to the atmosphere, the fine particles adhering to the surface of the X-ray optical element and the thin film formed on the surface can be easily removed by the movement displacement of the fine particles due to the irradiation of the energy beam. .

In the invention according to the second aspect, since the pulse width of the energy beam is 1 microsecond or less, the movement displacement of the substance attached to the surface of the X-ray optical element is
They can be large enough to reliably remove these substances.

In the invention according to claim 3, since the energy density per unit area of the pulsed energy beam incident on the surface of the X-ray optical element is variable, the pulsed energy beam adheres to the surface of the X-ray optical element. It is possible to irradiate an energy beam having an optimum intensity according to the properties of the particles and the properties of the thin film formed on the surface.

In the invention according to claim 4, the pulse-like energy beam incident on the surface of the X-ray optical element is
Since the irradiation position on the surface of the X-ray optical element is variable, it is possible to irradiate the energy beam intensively on a severely contaminated portion, and it is possible to efficiently remove the contaminant.

In the invention according to claim 5, in the reflecting mirror having a multilayer structure among the X-ray optical elements, the multilayer film has a number of layers capable of obtaining a sufficient reflectivity with respect to the X-rays to be used. Since the number of layers is larger than that, even if the uppermost layer of the underlying multilayer film is slightly removed, a sufficient number of films remain to obtain a high reflectance. You can keep the rate.

In the invention according to claim 6, in the reflecting mirror having a multilayer structure of the X-ray optical element, the multilayer film is a material having a smaller X-ray absorption coefficient among the materials forming the multilayer film. Since the layer is the uppermost layer and the thickness of the uppermost layer is thicker than the portion forming the periodic structure, even if the uppermost layer portion of the multilayer film is slightly removed, the structure of the periodic structure portion is The effect is small and a high reflectance can be maintained. In addition, since the uppermost portion having a large film thickness is a material having a smaller X-ray absorption coefficient, a decrease in soft X-ray reflectivity can be suppressed low.

In the invention according to claim 7, since the inert gas is introduced into the vacuum vessel during the irradiation of the pulsed energy beam, the removed substance is scattered by the introduced inert gas molecules. As a result, the optical performance of the soft X-ray optical element can be maintained because the momentum does not reach the other soft X-ray optical element.

According to the eighth aspect of the present invention, when the pulsed energy beam is radiated, the movable shielding plate which can cover the surface of an element other than the X-ray optical element to be irradiated is provided. When fine particles are removed by irradiating the line optical element with pulsed laser light, it is possible to prevent the fine particles from re-adhering to the surface of another element.

According to the ninth aspect of the present invention, at least one of oxygen and ozone, or a gas containing at least one of them, can be introduced into the vacuum vessel during the irradiation of the pulsed energy beam. Therefore, the carbon excited by the energy beam is combined with oxygen and becomes carbon dioxide, which is easily removed.

According to the tenth aspect of the present invention, a means for supplying water to the surface of the X-ray optical element to be irradiated at the time of pulsed energy beam irradiation is provided, so that a thin film of water or the like is formed on the surface. As a result, fine particles attached to the surface are effectively removed.

In the eleventh aspect of the present invention, since a continuous ultraviolet beam is used instead of the pulsed energy beam, it is particularly effective for removing carbon contamination.

According to the twelfth aspect of the present invention, the container accommodating the soft X-ray optical element is sealed, oxygen or ozone is introduced into the container, and the container passes through a transmission window through which a pulsed energy beam or ultraviolet light can be irradiated. Because it irradiates ultraviolet rays,
The path length of the ultraviolet ray exposed to oxygen or ozone is shortened, and the attenuation of the ultraviolet ray can be prevented.

In the invention according to the thirteenth aspect, since means for heating the X-ray optical element to which the pulsed energy beam or the continuous ultraviolet beam is applied is provided, the foreign matter adhered to the surface and the generated thin film are peeled off. It will be easier. When oxygen or ozone is present on the surface of the X-ray optical element, the reaction with these foreign substances or oxygen in the thin film is promoted.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first example of an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a second example of the embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing a third example of the embodiment of the present invention.

[Explanation of symbols]

101: X-ray, 102: Multi-layer reflector, 103: Mask stage, 104: Mask, 105: X-ray, 106, 1
07 ... KrF excimer laser beam, 108, 109 ... window,
110, 111: Reflecting mirror, 112: Vacuum container, 201:
Vacuum container, 202: X-ray generation unit, 203: nozzle, 20
4: pulse laser light, 205: lens, 206: pulse laser light introduction window, 207: plasma, 208: X
Line, 209: thin film filter, 210: multilayer reflector, 2
11 mask stage, 212 mask, 213 reflected X-ray, 214 multilayer mirror, 215 wafer stage, 216 silicon wafer, 217 pulse laser beam, 218 reflector mirror, 219 pulse laser beam, 2
20: introduction window, 221: reflection mirror, 222, 223, 22
4, 225: introduction windows, 226, 227, 228, 229
... Pulse laser light, 230, 231, 232, 233
... reflecting mirror, 235 ... gas inlet, 235 ... exhaust, 30
DESCRIPTION OF SYMBOLS 1 ... Soft X-ray optical element, 301 ... Soft X-ray optical element storage container, 303 ... Shielding plate, 304 ... Gas inlet, 305 ... Gas outlet, 306 ... Transmissive window, 310 ... Ultraviolet, 311 ...
Soft X-ray

Claims (13)

[Claims] 1. An X-ray apparatus comprising: an X-ray generation unit; and an X-ray optical system unit that extracts X-rays having a wavelength to be used from X-rays generated by the X-ray generation unit and converts the X-ray into a light beam suitable for a purpose of use. What is claimed is: 1. An X-ray apparatus, comprising: a mechanism for causing a pulsed energy beam to enter a surface of an X-ray optical element included in the X-ray apparatus. 2. The X-ray apparatus according to claim 1, wherein a pulse width of the energy beam is 1 microsecond or less. 3. The X-ray apparatus according to claim 1, wherein the energy density per unit area of the pulsed energy beam incident on the surface of the X-ray optical element is variable. 4. The irradiation position of the pulse-like energy beam incident on the surface of the X-ray optical element on the surface of the X-ray optical element is variable. The X-ray apparatus according to claim 1. 5. A reflecting mirror having a multilayer structure among X-ray optical elements, wherein the multilayer film has a larger number of layers than a layer capable of obtaining a sufficient reflectivity with respect to X-rays to be used. The X-ray apparatus according to any one of claims 1 to 4, wherein: 6. A reflecting mirror having a multilayer structure among the X-ray optical elements, wherein the multilayer film has a material layer having a smaller X-ray absorption coefficient among materials forming the multilayer film as an uppermost layer, The X-ray apparatus according to any one of claims 1 to 5, wherein a thickness of the upper layer is larger than a portion forming the periodic structure. 7. The X-ray apparatus according to claim 1, wherein an inert gas is introduced into the vacuum vessel when irradiating a pulsed energy beam. 8. When irradiating a pulsed energy beam,
2. A shielding device capable of covering the surface of an element other than the X-ray optical element to be irradiated.
The X-ray apparatus according to any one of claims 1 to 7. 9. The method according to claim 1, wherein at least one of oxygen and ozone, or a gas containing at least one of oxygen and ozone, can be introduced into the vacuum vessel during irradiation with the pulsed energy beam. The X-ray apparatus according to any one of claims 1 to 8. 10. The apparatus according to claim 1, further comprising a mechanism for supplying water to a surface of the X-ray optical element to be irradiated when the pulsed energy beam is irradiated. 2. The X-ray apparatus according to claim 1. 11. The X-ray apparatus according to claim 1, wherein a continuous ultraviolet beam is used instead of the pulsed energy beam. 12. A soft X-ray optical element is housed in a container,
The container can be hermetically or substantially hermetically sealed, and a mechanism for moving a portion of the container that blocks the optical path of soft X-ray out of the optical path during soft X-ray irradiation, and a soft X-ray optical element when hermetically or substantially hermetically sealed. 12. A transmission window capable of irradiating a pulsed energy beam or ultraviolet light on a surface thereof, and a gas introduction mechanism for introducing oxygen or ozone gas into a closed or substantially closed container. 2. The X-ray apparatus according to claim 1. 13. The apparatus according to claim 1, further comprising a mechanism for heating an X-ray optical element irradiated with a pulsed energy beam or a continuous ultraviolet beam. X-ray equipment.