JP2007150102A - Exposure device, and cleaning method of optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure device and the like where contaminant adhered to an optical element can be removed without damaging the optical element and also spoiling resist functions, even when the device is cleaned in situ without the disattachment of the optical element in the exposure device, in the case of the exposure device using projection exposure, especially the liquid immersion exposure method. <P>SOLUTION: The exposure device 1 comprises at least an exposure means 3 for exposing in the image itself to the surface to be exposed (surface of an object 5 to be exposed), by carrying out the exposure light emitting from an optical element 2; and a cleaning means 10 for cleaning the optical element 2 with cleaning fluid L by supplying the cleaning fluid L, so that the optical element 2 may be brought into contact with the fluid in the exposure device 1. The cleaning fluid L is at least either ultrapure water containing a surface-active agent or functional water which is obtained by dissolving at least one sort chosen from hydrogen, ozone and carbon dioxide into ultrapure water. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the exposure apparatus using the projection exposure, in particular, the immersion exposure method, the present invention is capable of cleaning in situ without removing the optical element in the exposure apparatus, and easily removing contaminants attached to the optical element. Exposure apparatus and exposure method capable of forming a fine and high-definition resist pattern with high efficiency, and an optical element cleaning apparatus and optical element cleaning capable of cleaning the optical element in situ in the exposure apparatus Regarding the method.

  When forming fine circuit patterns such as semiconductor elements and liquid crystal display elements, an exposure apparatus that selectively irradiates a substrate on which a photosensitive photoresist film is formed with short-wavelength light, an electron beam, or the like is used. ing. At present, with the high integration of semiconductor integrated circuits, the size of the minimum pattern extends to an area of 100 nm or less. ArF (Argon fluoride) excimer laser light ( A projection exposure apparatus using a wavelength of 193 nm) is used.

  In recent years, an immersion exposure method has attracted attention as the latest exposure technology for further pattern miniaturization. The immersion exposure method is an exposure technique that applies an immersion technique that is known in the field of microscopes. Specifically, a refraction between a projection optical system of an exposure apparatus and a substrate on which a circuit pattern is formed is refracted. This is a technique for improving the resolution by filling with a liquid having a refractive index higher than 1 (the refractive index of air), for example, water (the refractive index when the wavelength of exposure light is 193 nm is 1.44). According to the immersion exposure method, when the same exposure light source is used, a finer pattern can be formed as compared with normal projection exposure. For this reason, ArF excimer laser light, which is the current exposure light source, can be continuously used, and the cost can be reduced in that the exposure wavelength is not shortened.

  However, the adhesion of contaminants to the projection optical system has been a problem for a long time, and this problem has become apparent particularly in the immersion exposure method. That is, short-wavelength light such as ArF excimer laser light has extremely high energy, and the organic substance contained in the resist is chemically decomposed and gasified by irradiation with the short-wavelength light. It adheres to the optical elements in the system. In the immersion exposure method, the acid and other substances contained in the resist are directly dissolved in the solution filled between the projection optical system and the substrate on which the circuit pattern is formed. To the optical element. For this reason, in addition to the contaminant generated by the irradiation of the short wavelength light, a new contaminant due to immersion exposure adheres, resulting in diversification of contaminants attached to the optical element and an increase in the frequency of attachment. Therefore, as compared with the conventional exposure method using air as a medium, liquid immersion exposure is more likely to cause problems such as exposure failure due to a decrease in irradiation efficiency and a decrease in the lifetime of optical elements, which should be regarded as important. Yes.

When contaminants adhere to the optical element, cleaning the optical element can improve problems such as exposure failure. Conventionally, as a method for cleaning a projection optical system in a projection exposure apparatus, for example, A method of disassembling and cleaning an optical element from an exposure apparatus is known. However, in this case, it takes a lot of time to disassemble the optical element, and it is very difficult to reproduce the optical element without causing a deviation when it is assembled into the exposure apparatus again after being cleaned.
In view of this, various methods have been proposed for cleaning the optical element while it is mounted without disassembling the optical element from the exposure apparatus. For example, a method of directly wiping an optical element with a nonwoven fabric is known (see Patent Document 1). However, in this case, since the nonwoven fabric is in direct contact with the optical element, scratches and misalignment are likely to occur, and the throughput is reduced due to stoppage of the exposure apparatus.
In addition, a method for removing contaminants by irradiating an optical element with plasma or ultraviolet rays has been proposed (see Patent Document 2). However, even in this case, there is a problem that the optical element is damaged or the structure of the apparatus is complicated. In particular, immersion exposure is expected to increase the frequency of cleaning of optical elements due to the large amount of contaminants attached to optical elements compared to conventional projection exposure, resulting in excessive damage to optical elements. There is a risk of becoming.

  Therefore, the current situation is that a method of cleaning an optical element more easily and without reducing the throughput of device manufacture and without damaging the optical element, and related technology using the same have not been developed. Therefore, development of such technology is desired.

JP 2002-336804 A JP 2000-91207 A

An object of the present invention is to solve the conventional problems and achieve the following objects. That is,
In the exposure apparatus using the projection exposure, particularly the immersion exposure method, the present invention cleans in situ without removing the optical element in the exposure apparatus, does not damage the optical element, and does not impair the function of the resist. An object of the present invention is to provide an exposure apparatus and an exposure method capable of easily removing contaminants attached to the optical element and capable of forming a fine and high-definition resist pattern with high efficiency while suppressing exposure failure. And
The present invention also provides an exposure apparatus using projection exposure, particularly an immersion exposure method, in-situ cleaning without removing the optical element in the exposure apparatus, and without damaging the optical element. An object of the present invention is to provide an optical element cleaning apparatus and an optical element cleaning method capable of easily removing contaminants adhering to the surface.

Means for solving the above-described problems are as described in the following supplementary notes. That is,
The exposure apparatus of the present invention supplies exposure liquid that emits exposure light from an optical element and exposes the surface to be exposed imagewise, and a cleaning liquid so as to contact the optical element in the exposure apparatus, Cleaning means for cleaning the optical element with a cleaning liquid, and the cleaning liquid includes ultrapure water containing a surfactant and at least one selected from hydrogen, ozone and carbon dioxide. It is at least any one of functional water obtained by dissolving in water.
In the exposure apparatus, the exposure means emits the exposure light from the optical element and exposes the surface to be exposed imagewise. The cleaning means supplies the cleaning liquid so as to contact the optical element in the exposure apparatus, and cleans the optical element with the cleaning liquid. At this time, ultrapure water, functional water, or the like is used as the cleaning liquid. As a result, it is cleaned in situ without causing loss of function due to dissolution of the resist and without removing the optical element from the exposure apparatus, and contaminants attached to the optical element are easily removed. . For this reason, exposure failure due to contamination of the optical element is suppressed, and a fine and high-definition resist pattern can be formed with high efficiency.

The cleaning method of the optical element of the present invention is such that the cleaning liquid is brought into contact with the optical element which is the exposure light exit surface of the exposure means in an exposure apparatus having an exposure means for imagewise exposure to the exposed surface. Supplying at least a cleaning step of cleaning the optical element with the cleaning liquid, wherein the cleaning liquid includes ultrapure water containing a surfactant and at least one selected from hydrogen, ozone, and carbon dioxide. It is at least any one of functional water obtained by dissolving in water.
In the optical element cleaning method, in the cleaning step, the cleaning liquid is supplied so as to contact the optical element in the exposure apparatus, and the optical element is cleaned with the cleaning liquid. At this time, ultrapure water, functional water, or the like is used as the cleaning liquid. As a result, it is cleaned in situ without causing loss of function due to dissolution of the resist and without removing the optical element from the exposure apparatus, and contaminants attached to the optical element are easily removed. .

According to the present invention, conventional problems can be solved, and the above object can be achieved.
Further, according to the present invention, in an exposure apparatus using projection exposure, particularly an immersion exposure method, cleaning is performed in situ without removing the optical element in the exposure apparatus, the optical element is not damaged, and the resist functions. Provided are an exposure apparatus and an exposure method that can easily remove contaminants adhering to the optical element without damaging the optical element and can form a fine and high-definition resist pattern with high efficiency by suppressing exposure failure. be able to.
Further, according to the present invention, in an exposure apparatus using projection exposure, particularly an immersion exposure method, the optical element in the exposure apparatus is cleaned in situ without removing the optical element without damaging the optical element. It is possible to provide an optical element cleaning apparatus and an optical element cleaning method capable of easily removing contaminants attached to the element.

(Optical element cleaning method and optical element cleaning apparatus)
The optical element cleaning method of the present invention includes at least a cleaning step, and further includes other steps appropriately selected as necessary.
The optical element cleaning apparatus of the present invention includes at least a cleaning unit, and further includes other members appropriately selected as necessary.
The optical element cleaning method of the present invention can be preferably implemented using the optical element cleaning apparatus of the present invention, and the optical element cleaning apparatus is cleaned using the optical element cleaning apparatus of the present invention. If it carries out, it will have implemented the cleaning method of the above-mentioned optical element of the present invention.

<Washing process and cleaning means>
The cleaning step is a step of supplying a cleaning liquid so as to contact an optical element that is an exposure light emitting surface of the exposure means in an exposure apparatus having an exposure means, and cleaning the optical element with the cleaning liquid.
The cleaning unit has a function of supplying a cleaning liquid so as to contact an optical element that is an exposure light exit surface of the exposure unit in an exposure apparatus having an exposure unit, and cleaning the optical element with the cleaning liquid.
The washing step can be preferably performed by the washing means.
In the cleaning means and the cleaning process, the optical element is left in the exposure apparatus without any special work such as “in situ”, that is, removing the optical element from the exposure apparatus. Can be washed with.

The exposure means has a function of exposing the surface to be exposed imagewise.
The exposure means includes at least the optical element that is an exposure light exit surface, and further includes other members that are appropriately selected as necessary.
The optical element corresponds to an exposure light exit surface in the exposure unit, and examples of the optical element include an optical lens.

The surface to be exposed is not particularly limited as long as it is a surface to be exposed on the object to be exposed to the exposure light (object to be exposed), and can be appropriately selected according to the purpose. Suitable examples include resist films formed on the surface of semiconductor substrates such as various oxide films.
The method for imagewise exposure by the exposure means is not particularly limited and can be appropriately selected according to the purpose. Generally, the method is performed through a reticle (mask) on which a desired circuit pattern or the like is drawn. There is a method of forming a pattern image by irradiating the exposure surface with the exposure light. For example, when a solid image is formed on the entire surface to be exposed, the solid image is formed by directly irradiating the exposure surface with the exposure light without passing through the reticle (mask). be able to.

The exposure method is not particularly limited and can be appropriately selected depending on the purpose, and can be performed by a known projection exposure method. However, it is possible to form a finer pattern. The exposure by the immersion exposure method is preferable in that the cleaning effect of the optical element appears more remarkably.
In the immersion exposure method, the resolution is improved by filling a medium (liquid) having a refractive index n larger than 1 (the refractive index of air) between the optical element and the exposed surface. Can do. Usually, the resolution of the exposure means is expressed by the following equation: resolution = k (coefficient) × λ (light source wavelength) / NA (numerical aperture). The shorter the light source wavelength λ and the larger the numerical aperture NA of the optical element, the higher the resolution. Resolution can be obtained. Here, NA is represented by NA = n × sin α, n is the refractive index of the medium through which the exposure light passes, and α is the angle formed by the exposure light. Since the exposure in the conventional pattern forming method is performed in the air, the refractive index n is 1, but in the immersion exposure method, the refractive index n is greater than 1 between the optical element and the exposed surface. Use liquid. Therefore, in the numerical aperture NA equation, n is increased, and the minimum resolution dimension can be reduced to 1 / n at the same incident light incident angle α. Further, with the same numerical aperture NA, there is an advantage that α can be reduced and the depth of focus can be increased n times.

The liquid filled between the optical element and the surface to be exposed is not particularly limited and may be appropriately selected depending on the intended purpose. However, in terms of obtaining high resolution, the refractive index of air (refractive index). = 1) A liquid having a refractive index greater than 1) is preferred.
There is no restriction | limiting in particular as said liquid, Although it can select suitably according to the objective, It is so preferable that the said refractive index is large, for example, a pure water, oil, glycerol, alcohol etc. are mentioned suitably. Among these, pure water (refractive index = 1.44) is preferable.

  In the immersion exposure method, since the liquid is filled between the optical element and the exposed surface, when the resist film (exposed surface) is exposed to the liquid, the resist film is exposed during the exposure. When the exposure light is irradiated in the state that the acid component generated in the liquid oozes out into the liquid or the liquid penetrates into the resist film, some chemical reaction occurs, and the optical film is degassed from the resist film. There is a problem that the element is easily contaminated and exposure failure is likely to occur. However, according to the present invention, since the optical element is cleaned in situ in the exposure apparatus, contamination of the optical element is suppressed, and the cleaning effect is remarkable as compared with a normal exposure method. is there.

There is no restriction | limiting in particular as said exposure light, Although it can select suitably according to the objective, It is preferable that it is short wavelength light, for example, KrF excimer laser light (248 nm), ArF excimer laser light (193 nm) F ₂ excimer laser light (157 nm), EUV (soft X-ray region having a wavelength of 5 to 15 nm), and the like are preferable. Among these, ArF excimer laser light is preferable in that a high-definition resist pattern can be obtained.

-Cleaning solution-
As the cleaning liquid, it is necessary to use functional water obtained by dissolving at least one selected from ultrapure water containing a surfactant, hydrogen, ozone, and carbon dioxide in ultrapure water. These may be used individually by 1 type, may use 2 or more types together, and can be suitably selected according to the characteristic of the organic pollutant derived from the resist adhering to the said optical element.

The ultrapure water containing the surfactant is not particularly limited and may be appropriately selected depending on the purpose. Examples of the surfactant include a nonionic surfactant, a cationic surfactant, and an anionic property. Surfactant, amphoteric surfactant and the like can be mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, nonionic surfactants are preferable from the viewpoint of stability.
Examples of the nonionic surfactant include alkoxylate surfactants, fatty acid ester surfactants, amide surfactants, alcohol surfactants, and ethylenediamine surfactants. Specific examples include, for example, polyoxyethylene-polyoxypropylene condensate, polyoxyalkylene alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene derivative, sorbitan fatty acid ester, glycerin fatty acid ester, primary alcohol Ethoxylate, phenol ethoxylate, nonylphenol ethoxylate, octylphenol ethoxylate, lauryl alcohol ethoxylate, oleyl alcohol ethoxylate, fatty acid ester, amide, natural al Lumpur-based, ethylene diamine, secondary alcohol ethoxylate, and the like.
Examples of the cationic surfactant include alkyl cationic surfactants, amide or ester type quaternary cationic surfactants, and the like.
Examples of the amphoteric surfactant include amine oxide surfactants and betaine surfactants.

Among the cleaning liquids, in order to prevent the generation of impurities and improve the durability of the optical element and the exposure apparatus, functional water is preferable, and the cleaning effect on organic contaminants generated from the resist film is high. Functional water obtained by dissolving ozone in ultrapure water is particularly preferred.
Further, when two or more kinds are selected from the hydrogen, the ozone, and the carbon dioxide and used in combination, the hydrogen exhibits an effect in removing small pieces of contaminants attached to the surface of the optical element, and the carbon dioxide. Since carbon imparts an antistatic effect to the surface of the optical element, it is particularly preferable to use the hydrogen and the carbon dioxide in combination with the ozone.

  The amount of the hydrogen, ozone, or carbon dioxide dissolved in the ultrapure water (the dissolved concentration of the gas in the ultrapure water) is not particularly limited and may be appropriately selected depending on the intended purpose. Is preferably 400 ppm. When the dissolved concentration exceeds 400 ppm, the optical element may be damaged. Further, the lower limit value is not particularly limited because there are few adverse effects due to the low concentration, and can be appropriately selected according to the purpose. However, 1 ppm is preferable in that the cleaning processing time can be shortened.

The cleaning means needs to supply the cleaning liquid so as to contact the optical element in the exposure apparatus. In this case, the optical element can be easily cleaned in situ in the exposure apparatus without removing the optical element from the exposure apparatus.
The position for supplying the cleaning liquid is not particularly limited as long as it can be brought into contact with the optical element, can be appropriately selected according to the purpose, and may be on the exposed surface, or the exposed surface It may be a part other than the surface. In addition, as a part other than the surface to be exposed, for example, a substrate prepared on a cleaning processing region provided in a part of a stage on which a substrate such as the silicon wafer in the exposure apparatus is mounted or separately prepared for cleaning processing (Dummy wafer) and the like.

There is no restriction | limiting in particular as a supply method of the said washing | cleaning liquid, Although it can select suitably according to the objective, It can carry out suitably with the said washing | cleaning means.
Suitable examples of the cleaning means include an ejection nozzle that can eject the cleaning liquid so as to contact the optical element. The ejection nozzle may be used in combination with a nozzle for supplying the immersion exposure liquid.
It is preferable that the cleaning means further includes a container for storing the cleaning liquid, and it is preferable to store the cleaning liquid in the container.

There is no restriction | limiting in particular as the frequency | count of supply of the said washing | cleaning liquid, According to the degree of the contamination of the said optical element, it can select suitably, 1 time may be sufficient and multiple times may be sufficient.
Moreover, there is no restriction | limiting in particular as supply_amount | feed_rate of the said washing | cleaning liquid, According to the objective, it can select suitably.

The cleaning method of the optical element is not particularly limited as long as the cleaning liquid is brought into contact with the optical element, and can be appropriately selected according to the purpose. For example, (1) each time the exposure light is irradiated by one shot (2) A method of cleaning each time one lot of the exposure light is irradiated, (3) A method of cleaning according to the exposure time and dose of the exposure light, and (4) Light transmission of the optical element A method of washing according to the rate is preferable.
Specifically, in the cleaning method according to (1), the optical element is cleaned with the cleaning liquid every time the exposure light is irradiated with one unit of a certain region (area) on the exposed surface. In the cleaning method described in (2), for example, each time the exposure light is irradiated to one lot of several substrates to several tens of substrates such as the silicon wafer as one unit, In the cleaning method according to (3), the optical element is cleaned each time the exposure light is irradiated with respect to the unit, with the constant irradiation time or the fixed irradiation amount of the exposure light as one unit. In the cleaning method according to (4), the degree of contamination of the optical element is detected, for example, by measuring the light transmittance using a transmittance detector, and the transmittance exceeds a specific value. At that point, the optical element is automatically cleaned

  There is no restriction | limiting in particular as a place which supplies the said washing | cleaning liquid and the said optical element, It can select suitably according to the objective, You may carry out on the to-be-exposed surface, Other than the to-be-exposed surface You may go at the place. Usually, in the cleaning methods described in (1) to (4), cleaning is performed on the exposed surface. However, when the cleaning is performed at a place other than the exposed surface, for example, the substrate in the exposure apparatus is placed. A cleaning process area may be provided in a part of the stage to be cleaned, and cleaning may be performed on the cleaning process area, or a separate substrate (dummy wafer) is prepared for the cleaning process, and cleaning is performed on the dummy wafer. Also good. When cleaning is performed in the cleaning process area, the optical element is moved to the cleaning process area before cleaning.

  Through the above steps, the cleaning liquid is supplied so as to contact the optical element in the exposure apparatus, and the optical element is cleaned by the cleaning liquid.

The optical element cleaning method of the present invention may include a suction step, and the optical element cleaning device of the present invention may include a suction means.
The suction step is a step of sucking the cleaning liquid after cleaning.
The suction means has a function of sucking the cleaning liquid after cleaning.
The suction step can be preferably performed by the suction means.

There is no restriction | limiting in particular as the suction method of the said washing | cleaning liquid, Although it can select suitably according to the objective, For example, it can carry out suitably with the said suction means.
Suitable examples of the suction means include a suction nozzle that can suck the cleaning liquid after cleaning. The suction nozzle may be used in combination with a nozzle that sucks the liquid for immersion exposure.
Through the above steps, the cleaning liquid after cleaning is sucked.
It is preferable that the cleaning liquid sucked by the suction step is recovered in, for example, a recovery container.

  In the optical element cleaning method of the present invention, in the cleaning step, the cleaning liquid is supplied so as to be in contact with the optical element in the exposure apparatus, and the optical element is cleaned with the cleaning liquid. At this time, ultrapure water, functional water, or the like is used as the cleaning liquid. As a result, the optical element is cleaned in situ without being removed from the exposure apparatus, and the contaminants attached to the optical element can be easily removed without damaging the optical element and without impairing the function of the resist. Can be removed.

In the optical element cleaning apparatus of the present invention, the cleaning means supplies the cleaning liquid so as to contact the optical element in the exposure apparatus, and cleans the optical element with the cleaning liquid. At this time, ultrapure water, functional water, or the like is used as the cleaning liquid. As a result, the optical element is cleaned in situ without being removed from the exposure apparatus, contaminants attached to the optical element can be easily removed, and loss of function due to dissolution of the resist does not occur.
Therefore, the optical element cleaning apparatus of the present invention is suitably used for exposure apparatuses of all aspects such as a batch exposure type stepper, a scanning exposure type scanning stepper, an immersion exposure apparatus, and other types of exposure apparatuses. And can be used particularly preferably in an immersion exposure apparatus.

(Exposure method and exposure apparatus)
The exposure method of the present invention includes at least an exposure step and a cleaning step, and further includes other steps appropriately selected as necessary.
The exposure apparatus of the present invention includes at least an exposure unit and a cleaning unit, and further includes other members appropriately selected as necessary.
The exposure method of the present invention can be suitably implemented using the exposure apparatus of the present invention. When the exposure apparatus of the present invention is implemented, the exposure method of the present invention is implemented.
The exposure apparatus is not particularly limited and may be appropriately selected according to the purpose. Any one of a batch exposure type stepper, a scanning exposure type scanning stepper, an immersion exposure apparatus, and other types of exposure apparatuses may be used. The exposure apparatus of the aspect is mentioned.

<Exposure process and exposure means>
The exposure step is a step in which exposure light is emitted from an optical element that is an exposure light emission surface of the exposure means, and the exposure surface is imagewise exposed.
The exposure means has a function of emitting exposure light from the optical element and exposing the exposed surface imagewise.
The exposure step can be preferably performed by the exposure means.

The exposure means includes at least an optical element, and further includes other members appropriately selected as necessary.
The optical element corresponds to an exposure light exit surface in the exposure unit, and examples of the optical element include an optical lens.
The details of the surface to be exposed, the imagewise exposure method, the exposure light, and the like are as described above in the description of the optical element cleaning method and the optical element cleaning apparatus of the present invention.

The exposure method is not particularly limited and may be appropriately selected depending on the purpose, and can be performed by a known projection exposure method. However, the optical element is also capable of forming a finer pattern. The exposure by the liquid immersion exposure method is preferable in that the cleaning effect of (1) appears more remarkably.
The details of the immersion exposure method are as described above in the description of the optical element cleaning apparatus, the optical element cleaning method, and the optical element cleaning apparatus of the present invention.

<Washing process and cleaning means>
The cleaning step is a step of supplying a cleaning liquid so as to contact an optical element that is an exposure light emitting surface of an exposure unit in the exposure apparatus, and cleaning the optical element with the cleaning liquid.
The cleaning unit has a function of supplying a cleaning liquid so as to contact an optical element that is an exposure light exit surface of the exposure unit in the exposure apparatus, and cleaning the optical element with the cleaning liquid.
The washing step can be preferably performed by the washing means.

-Cleaning solution-
As the cleaning liquid, it is necessary to use functional water obtained by dissolving at least one selected from ultrapure water containing a surfactant, hydrogen, ozone, and carbon dioxide in ultrapure water. These may be used individually by 1 type, may use 2 or more types together, and can be suitably selected according to the characteristic of the organic pollutant derived from the resist adhering to the said optical element.

The ultrapure water containing the surfactant is not particularly limited and may be appropriately selected depending on the purpose. Examples of the surfactant include a nonionic surfactant, a cationic surfactant, and an anionic property. Surfactant, amphoteric surfactant and the like can be mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, nonionic surfactants are preferable from the viewpoint of stability.
Examples of the nonionic surfactant include alkoxylate surfactants, fatty acid ester surfactants, amide surfactants, alcohol surfactants, and ethylenediamine surfactants. Specific examples include, for example, polyoxyethylene-polyoxypropylene condensate, polyoxyalkylene alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene derivative, sorbitan fatty acid ester, glycerin fatty acid ester, primary alcohol Ethoxylate, phenol ethoxylate, nonylphenol ethoxylate, octylphenol ethoxylate, lauryl alcohol ethoxylate, oleyl alcohol ethoxylate, fatty acid ester, amide, natural al Lumpur-based, ethylene diamine, secondary alcohol ethoxylate, and the like.
Examples of the cationic surfactant include alkyl cationic surfactants, amide or ester type quaternary cationic surfactants, and the like.
Examples of the amphoteric surfactant include amine oxide surfactants and betaine surfactants.

Among the cleaning liquids, in order to prevent the generation of impurities and improve the durability of the optical element and the exposure apparatus, functional water is preferable, and the cleaning effect on organic contaminants generated from the resist film is high. Functional water obtained by dissolving ozone in ultrapure water is particularly preferred.
Further, when two or more kinds are selected from the hydrogen, the ozone, and the carbon dioxide and used in combination, the hydrogen exhibits an effect in removing small pieces of contaminants attached to the surface of the optical element, and the carbon dioxide. Since carbon imparts an antistatic effect to the surface of the optical element, it is particularly preferable to use the hydrogen and the carbon dioxide in combination with the ozone.

  The amount of the hydrogen, ozone, or carbon dioxide dissolved in the ultrapure water (the dissolved concentration of the gas in the ultrapure water) is not particularly limited and may be appropriately selected depending on the intended purpose. Is preferably 400 ppm. When the dissolved concentration exceeds 400 ppm, the optical element may be damaged. Further, the lower limit value is not particularly limited because there are few adverse effects due to the low concentration, and can be appropriately selected according to the purpose. However, 1 ppm is preferable in that the cleaning processing time can be shortened.

The cleaning means needs to supply the cleaning liquid so as to contact the optical element in the exposure apparatus. In this case, the optical element can be easily cleaned in situ in the exposure apparatus without removing the optical element from the exposure apparatus.
The position for supplying the cleaning liquid is not particularly limited as long as it can be brought into contact with the optical element, can be appropriately selected according to the purpose, and may be on the exposed surface, or the exposed surface It may be a part other than the surface. In addition, as a part other than the surface to be exposed, for example, a substrate prepared on a cleaning processing region provided in a part of a stage on which a substrate such as the silicon wafer in the exposure apparatus is mounted or separately prepared for cleaning processing (Dummy wafer) and the like.

There is no restriction | limiting in particular as a supply method of the said washing | cleaning liquid, Although it can select suitably according to the objective, For example, it can carry out suitably with a washing | cleaning means.
Suitable examples of the cleaning means include an ejection nozzle that can eject the cleaning liquid so as to contact the optical element. The ejection nozzle may be used in combination with a nozzle for supplying the immersion exposure liquid.
It is preferable that the cleaning means further includes a container for storing the cleaning liquid, and it is preferable to store the cleaning liquid in the container.

There is no restriction | limiting in particular as the frequency | count of supply of the said washing | cleaning liquid, According to the degree of the contamination of the said optical element, it can select suitably, 1 time may be sufficient and multiple times may be sufficient.
Moreover, there is no restriction | limiting in particular as supply_amount | feed_rate of the said washing | cleaning liquid, According to the objective, it can select suitably.

The cleaning method of the optical element is not particularly limited as long as the cleaning liquid is brought into contact with the optical element, and can be appropriately selected according to the purpose. For example, (1) each time the exposure light is irradiated by one shot (2) A method of cleaning each time one lot of the exposure light is irradiated, (3) A method of cleaning according to the exposure time and dose of the exposure light, and (4) Light transmission of the optical element A method of washing according to the rate is preferable.
Specifically, in the cleaning method according to (1), the optical element is cleaned with the cleaning liquid every time the exposure light is irradiated with one unit of a certain region (area) on the exposed surface. In the cleaning method described in (2), for example, each time the exposure light is irradiated to one lot of several substrates to several tens of substrates such as the silicon wafer as one unit, In the cleaning method according to (3), the optical element is cleaned each time the exposure light is irradiated with respect to the unit, with the constant irradiation time or the fixed irradiation amount of the exposure light as one unit. In the cleaning method according to (4), the degree of contamination of the optical element is detected, for example, by measuring the light transmittance using a transmittance detector, and the transmittance exceeds a specific value. At that point, the optical element is automatically cleaned

  There is no restriction | limiting in particular as a place which supplies the said washing | cleaning liquid and the said optical element, It can select suitably according to the objective, You may carry out on the to-be-exposed surface, Other than the to-be-exposed surface You may go at the place. Usually, in the cleaning methods described in (1) to (4), cleaning is performed on the exposed surface. However, when the cleaning is performed at a place other than the exposed surface, for example, the substrate in the exposure apparatus is placed. A cleaning process area may be provided in a part of the stage to be cleaned, and cleaning may be performed on the cleaning process area, or a separate substrate (dummy wafer) is prepared for the cleaning process, and cleaning is performed on the dummy wafer. Also good. When cleaning is performed in the cleaning process area, the optical element is moved to the cleaning process area before cleaning.

  Through the above steps, the cleaning liquid is supplied so as to contact the optical element in the exposure apparatus, and the optical element is cleaned by the cleaning liquid.

The exposure method of the present invention may include a suction step, and the exposure apparatus of the present invention may have a suction means.
The suction step is a step of sucking the cleaning liquid after cleaning.
The suction means has a function of sucking the cleaning liquid after cleaning.
The suction step can be preferably performed by the suction means.

There is no restriction | limiting in particular as the suction method of the said washing | cleaning liquid, Although it can select suitably according to the objective, For example, it can carry out suitably with the said suction means.
Suitable examples of the suction means include a suction nozzle that can suck the cleaning liquid after cleaning. The suction nozzle may be used in combination with a nozzle that sucks the liquid for immersion exposure.

Through the above steps, the cleaning liquid after cleaning is sucked.
It is preferable that the cleaning liquid sucked by the suction step is recovered in, for example, a recovery container.

Here, an example of the exposure apparatus and exposure method of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic explanatory view showing an example of an exposure apparatus (immersion exposure method) according to the present invention. The exposure apparatus 1 includes an exposure means 3 having a projection lens 2 as the optical element (exposure light exit surface), and a wafer stage 4. The wafer stage 4 is provided so that an object to be exposed (substrate such as a silicon wafer) 5 can be mounted, and a medium (liquid) is provided between the projection lens 2 and the object to be exposed 5 on the wafer stage 4. The liquid 8 for immersion exposure is supplied between the projection lens 2 and the surface to be exposed by a liquid supply device (not shown) before exposure, and is not shown after exposure. The liquid 8 is recovered by a liquid recovery device. Then, when exposure light is irradiated onto the reticle 7 from the illumination optical system 6, the pattern image formed by the reticle 7 is projected onto the exposure target 5 through the projection lens 2 in the exposure means 3, and the exposure surface (exposed surface) For example, a circuit pattern is formed on the object 5).

The exposure apparatus 1 has a cleaning device for the optical element. That is, as shown in FIG. 2, a cleaning liquid ejecting apparatus 10 as the cleaning means and a cleaning liquid suction apparatus 20 as the suction means are provided. The cleaning liquid ejecting apparatus 10 and the cleaning liquid suction apparatus 20 correspond to the optical element cleaning apparatus of the present invention.
The cleaning liquid ejecting apparatus 10 includes a cleaning liquid container 12 that stores the cleaning liquid L and an ejection nozzle 14 that ejects the cleaning liquid. The cleaning liquid suction apparatus 20 collects the suction cleaning liquid L that sucks the cleaning liquid L and the suctioned cleaning liquid L. And a cleaning liquid recovery device 22.

First, a to-be-exposed object 5 is produced by forming a resist film on a substrate such as a silicon wafer. The exposed surface corresponds to the resist film surface in the object 5 to be exposed.
Next, as shown in FIG. 1, the object to be exposed 5 is placed on the wafer stage 4 of the exposure apparatus 1, and exposure light (for example, ArF excimer laser light) is irradiated onto the reticle 7 from the illumination optical system 6. Then, a pattern image is formed by the reticle 7, and the pattern image passes through the projection lens 2 in the exposure unit 3, and further passes through the liquid 8 having a refractive index larger than 1, and is projected onto the exposure target 5. The As a result, for example, a circuit pattern is formed on the exposed surface (exposed object 5). Before exposure, the liquid 8 for immersion exposure is supplied between the projection lens 2 and the surface to be exposed by a liquid supply device (not shown). After the exposure, the liquid 8 is supplied by a liquid recovery device (not shown). Recover. The above is the exposure step.
After recovering the liquid 8 for immersion exposure, as shown in FIG. 2, the cleaning liquid L stored in the cleaning liquid container 12 in the cleaning liquid ejecting apparatus 10 is ejected from the ejection nozzle 14 onto the exposed surface and projected. A cleaning liquid L is interposed between the lens 2 and the exposed surface, and the cleaning liquid L is brought into contact with the projection lens 2. Then, contaminants attached to the projection lens 2 are removed by the cleaning liquid L. The above is the cleaning step.
Thereafter, the cleaning liquid L after cleaning is sucked using the suction nozzle 24 in the cleaning liquid suction device 20, and the suctioned cleaning liquid L is collected in the cleaning liquid collector 22. The above is the suction step.
If necessary, the supply of the liquid 8, exposure, the recovery of the liquid 8, the cleaning of the cleaning liquid L, and the recovery of the cleaning liquid L are repeated in this order, and finally an alkali development process is performed. The region not irradiated with ArF excimer laser light is dissolved and removed, and a resist pattern is formed (developed) on the exposed surface (exposed object 5).

FIG. 3 is a schematic explanatory view showing an example of the exposure apparatus of the present invention.
The exposure apparatus 30 shown in FIG. 3 is a process for cleaning the projection lens 2 on at least a part of the part other than the exposure surface (exposed object 5) on the wafer stage 4 in the exposure apparatus 1 shown in FIGS. An area S is provided, and the projection lens 2 is moved to the position of the cleaning area S. Then, the cleaning liquid L stored in the cleaning liquid container 12 is ejected from the ejection nozzle 14 into the cleaning processing area S on the wafer stage 4, cleaned by contacting the projection lens 2, and then sucked from the suction nozzle 24. It collects in the cleaning liquid collector 22.

FIG. 4 is a schematic explanatory view showing an example of the exposure apparatus of the present invention.
The exposure apparatus 40 shown in FIG. 4 ejects the liquid stored in the liquid container 42 and the cleaning liquid L stored in the cleaning liquid container 43 from the same ejection nozzle 44 as the cleaning means, and after exposure. And the cleaning liquid L after cleaning are sucked by the same suction nozzle 47 as the suction means, and are recovered in the liquid recovery unit 45 and the cleaning liquid recovery unit 46, respectively.

  In the exposure method of the present invention, in the cleaning step, the cleaning liquid is supplied so as to be in contact with the optical element in the exposure apparatus, and the optical element is cleaned with the cleaning liquid. At this time, ultrapure water, functional water, or the like is used as the cleaning liquid. As a result, the optical element is cleaned in situ without being removed from the exposure apparatus, and the contaminants attached to the optical element can be easily removed without damaging the optical element and without impairing the function of the resist. Can be removed.

In the exposure apparatus of the present invention, the cleaning means supplies the cleaning liquid so as to contact the optical element in the exposure apparatus, and cleans the optical element with the cleaning liquid. At this time, ultrapure water, functional water, or the like is used as the cleaning liquid. As a result, the optical element is cleaned in situ without being removed from the exposure apparatus, contaminants attached to the optical element can be easily removed, and loss of function due to dissolution of the resist does not occur.
Therefore, it is possible to easily and efficiently form a fine and high-definition resist pattern while suppressing exposure failure. For example, the resist pattern may be a mask pattern, a reticle pattern, a magnetic head, an LCD (liquid crystal display), a PDP, or the like. (Plasma display panel), SAW filter (surface acoustic wave filter) and other functional parts, optical parts used for connecting optical wiring, microactuators and other fine parts, and semiconductor devices and other electronic devices be able to.

Below, an example of the manufacturing method of the electronic device performed using the said exposure apparatus of this invention is demonstrated.
The manufacturing method of the electronic device includes at least a resist pattern forming step and a patterning step, and further includes other steps appropriately selected as necessary.

<Resist pattern formation process>
The resist pattern forming step is a step of forming a resist film on the surface to be processed, and then exposing and developing the resist film using the exposure apparatus of the present invention to form a resist pattern. A resist pattern is formed on the processed surface by the resist pattern forming step.

The resist film is formed on the surface to be processed.
The material of the resist film is not particularly limited and can be appropriately selected from known resist materials according to the purpose, and may be either a negative type or a positive type. For example, a KrF excimer laser, Preferable examples include KrF resist, ArF resist, and F ₂ resist that can be patterned with an ArF excimer laser, an F ₂ excimer laser, or the like. These may be chemically amplified or non-chemically amplified. Among these, a KrF resist, an ArF resist, a resist containing an acrylic resin, and the like are preferable. From the viewpoint of finer patterning, an improvement in throughput, and the like, an ArF resist whose extension of the resolution limit is urgently required. And at least one of resists comprising an acrylic resin is more preferable.
Specific examples of the resist film forming material include novolak resist, PHS resist, acrylic resist, cycloolefin-maleic anhydride (COMA) resist, cycloolefin resist, and hybrid (alicyclic acrylic). -COMA copolymer) resist and the like. These may be modified with fluorine.
There is no restriction | limiting in particular about the formation method of a resist film, a magnitude | size, thickness, etc., According to the objective, it can select suitably, It can form by a well-known method, for example, application | coating etc. The thickness can be appropriately determined depending on the surface to be processed, etching conditions, and the like, but is generally about 50 to 400 nm.

  The surface to be processed (base material) is not particularly limited and may be appropriately selected according to the purpose. However, when the resist film is formed on an electronic device such as a semiconductor device, the surface to be processed Examples of (base material) include the surface of a semiconductor base material, specifically, a substrate such as a silicon wafer, various oxide films, and the like.

-Exposure-
The exposure is performed using the exposure apparatus of the present invention. When the exposure light is irradiated to a partial area of the resist film by the exposure, the partial area is cured, and uncured other than the cured partial area in development described later. The region is removed and a resist pattern is formed.
The exposure method is not particularly limited as long as the exposure apparatus of the present invention is used, and can be appropriately selected according to the purpose. However, the exposure method is preferably performed.
The details of the exposure apparatus and the immersion exposure method are as described above in the description of the exposure apparatus and exposure method of the present invention.

-Development-
The development is performed by exposing the resist film using the exposure apparatus of the present invention, curing the exposed area of the resist film, and then removing the uncured area. A resist pattern is formed by the development.
There is no restriction | limiting in particular as the removal method of the said unhardened area | region, According to the objective, it can select suitably, For example, the method etc. which remove using a developing solution are mentioned.
There is no restriction | limiting in particular as said developing solution, Although it can select suitably according to the objective, It is preferable that it is an alkaline developing solution. By performing development with the alkali developer, a portion of the resist film that is not irradiated with the exposure light is dissolved and removed, and a resist pattern is formed (developed).

<Patterning process>
The patterning step is a step of patterning the substrate to be processed by etching using the resist pattern as a mask (using as a mask pattern or the like).
There is no restriction | limiting in particular as the said etching method, Although it can select suitably according to the objective from well-known methods, For example, dry etching is mentioned suitably. The etching conditions are not particularly limited and can be appropriately selected depending on the purpose.

  According to the manufacturing method of the electronic device, since the exposure apparatus of the present invention is used, exposure failure due to contamination of the optical element is suppressed, and a fine and high-definition resist pattern can be easily and efficiently formed. Efficient mass production of high-performance electronic devices having a fine wiring pattern formed using a resist pattern, such as various semiconductor devices such as flash memory, DRAM, FRAM, thin film magnetic head, etc. Can do.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

Example 1
First, a trial resist material for ArF excimer laser light containing an alicyclic polymer is spin-coated on a Si substrate under conditions of 3,500 rpm and 45 s by spin coating, and baked on a 110 ° C. hot plate for 60 seconds. Then, a resist film having a thickness of 300 nm was formed, and the object to be exposed was prepared using the resist film as the exposed surface.
Next, the obtained object to be exposed (Si substrate with a resist film formed on the surface) was placed on the wafer stage of the ArF excimer laser prototype immersion exposure apparatus. Water as a medium having a refractive index larger than 1 contained in the liquid container is supplied between the projection lens and the resist film, and in this state, ArF excimer laser light as the exposure light is emitted from the projection lens. Then, a total of 500 J / cm ^{2 was} irradiated to the resist film as the exposed surface. The above is the exposure step in the exposure method of the present invention. After irradiation, when the irradiation efficiency was measured using an illuminometer (“IL1400”; manufactured by International Light), the illuminance before irradiation was 75.0%.

  Subsequently, functional water in which ozone was dissolved in ultrapure water so as to have a dissolved concentration of 15 ppm was prepared as the cleaning liquid. The obtained functional water (cleaning liquid) was put in a Teflon container, and the projection lens was cleaned by placing the liquid surface in contact with the projection lens. The above is the cleaning step in the optical element cleaning method of the present invention and the exposure method of the present invention. The illuminance at this time was measured using the illuminometer, and the cleaning performance of the projection lens was evaluated from the relationship between the cleaning time and the illuminance. The results are shown in Table 1.

表１より、洗浄液を投影レンズに３秒間接触させて洗浄すると、照度が９８％以上に回復することが判った。
また、実施例１では、ＡｒＦエキシマレーザー光を合計５００Ｊ／ｃｍ^２照射することにより、７５％に照度が低下した汚染に対して、３秒間で充分な効果が得られていることが明確であり、これに対して、例えば、洗浄方法として前述した１ショット照射する毎に洗浄を行う方法を採る場合には、実施例１に比較して投影レンズに付着する汚れも軽微であると考えられるため、１〜３秒間程度洗浄を行うと、投影レンズの汚れを充分に除去することができるといえる。また、露光光を１ロット照射する毎に洗浄する場合や、露光光を一定時間照射する毎に洗浄する場合でも、３０秒間程度洗浄を行えば、汚れを充分に除去することができると認められた。

From Table 1, it was found that when the cleaning liquid was brought into contact with the projection lens for 3 seconds for cleaning, the illuminance recovered to 98% or more.
Moreover, in Example 1, it is clear that a sufficient effect is obtained in 3 seconds against contamination whose illuminance is reduced to 75% by irradiation with a total of 500 J / cm ^{2 of} ArF excimer laser light. On the other hand, for example, in the case where the cleaning method is performed every time one shot is irradiated as described above, it is considered that the dirt adhering to the projection lens is slight compared to the first embodiment. It can be said that if the cleaning is performed for about 1 to 3 seconds, the dirt on the projection lens can be sufficiently removed. In addition, even when cleaning is performed every time one lot of exposure light is irradiated, or when cleaning is performed every time exposure light is irradiated for a certain period of time, if it is cleaned for about 30 seconds, it is recognized that dirt can be sufficiently removed. It was.

(Example 2)
-Characterization of functional water-
The solubility of the resist film with functional water as the cleaning liquid was measured by the following method.
First, a trial resist material for ArF excimer laser light containing an alicyclic polymer is spin-coated on a Si substrate under conditions of 3,500 rpm and 45 s by spin coating, and baked on a 110 ° C. hot plate for 60 seconds. A resist film was formed.
In addition, ozone was dissolved in ultrapure water so that the dissolved concentration was 15 ppm to prepare functional water as the cleaning liquid.
2 mL of functional water was dropped onto the surface of the obtained resist film, and the relationship between the time (washing time) when the functional water contacted the surface of the resist film at the dripping portion and the change in film thickness of the resist film was measured. The thickness of the resist film was measured using a contact-type film thickness meter (“α step 3000”; manufactured by Tencor). The results are shown in Table 2.

  From Table 2, it was found that the film thickness did not change until the contact time was 120 seconds with respect to the initial film thickness of 300.2 nm. From Table 1 above, the cleaning time of the optical element (contact time between the resist film and the cleaning solution) has a sufficient cleaning effect within a few seconds, and can be sufficiently cleaned with a cleaning time of about 30 seconds at the longest. Therefore, it was found that the optical element can be cleaned within the cleaning time (contact time) without damaging the resist film with functional water.

(Example 3)
Next, the ozone concentration dependence of the characteristics of functional water was evaluated.
Ozone was dissolved in ultrapure water so that the dissolved concentration was 80 ppm to prepare functional water as the cleaning liquid. Using the obtained functional water, the projection lens was immersed and washed in the same manner as in Example 1 with an ozone concentration of 15 ppm, the illuminance at this time was measured, and the time when the functional water contacted the projection lens (cleaning Time) and illuminance. The results are shown in Table 3.

  Further, in the same manner as in Example 2, the relationship between the time when the functional water contacted the surface of the resist film (cleaning time) and the change in the film thickness of the resist film was measured. The results are shown in Table 4.

  From Table 3, it was found that when the ozone concentration was 80 ppm, the cleaning effect was improved and the illuminance of the projection lens (optical element) was recovered in a short time. On the other hand, as shown in Table 4, since the resist film thickness is slightly reduced when processed for a long time, in such a case, for example, as in the exposure apparatus shown in FIG. S is preferably provided, and the projection lens is cleaned in the cleaning region S.

Example 4
Similar to Example 1, first, a 300-nm-thick resist film was formed on a Si substrate using a prototype resist material for ArF excimer laser light containing an alicyclic polymer, and the resist film was formed as the exposed surface. The object to be exposed was prepared.
Next, the obtained object to be exposed (Si substrate with a resist film formed on the surface) was placed on the wafer stage of the ArF excimer laser prototype immersion exposure apparatus. Water as a medium having a refractive index larger than 1 contained in the liquid container is supplied between the projection lens and the resist film, and in this state, ArF excimer laser light as the exposure light is emitted from the projection lens. Then, a total of 5,000 mJ / cm ^{2 was} applied to the resist film as the exposed surface.
Next, functional water in which ozone is dissolved in ultrapure water so as to have a dissolved concentration of 15 ppm is prepared as the cleaning liquid, and this is supplied at a flow rate of 1 mL / s so as to contact the projection lens. The projection lens was cleaned by performing a cleaning method of sucking the water after contact at 2 for 2 seconds. The above is the cleaning step in the optical element cleaning method of the present invention and the exposure method of the present invention. After irradiating ArF excimer laser light (5,000 mJ / cm ² ) and cleaning the optical element with the functional water 100 times, the illuminance was measured using the illuminometer. There was no change.

(Example 5)
As in Example 4, a 300-nm-thick resist film is formed on a Si substrate using a prototype resist material for ArF excimer laser light containing an alicyclic polymer, and the resist film is used as the exposed surface. An object to be exposed was prepared.
Next, the obtained object to be exposed (Si substrate with a resist film formed on the surface) was placed on the wafer stage of the ArF excimer laser prototype immersion exposure apparatus. Water as a medium having a refractive index larger than 1 contained in the liquid container is supplied between the projection lens and the resist film, and in this state, ArF excimer laser light as the exposure light is passed through the reticle to the projection lens. The resist film was exposed to 100 mJ / cm ² for one shot, and a total of 50 shots were exposed. At that time, the water as the immersion exposure medium is exchanged for each shot, and the functional water in which ozone is dissolved at a concentration of 15 ppm is exchanged at a flow rate of 1 mL / s for 1 second while the water as the medium is exchanged. At the same time, the projection lens was cleaned by a cleaning method of sucking water after contact at the same flow rate. After irradiation with ArF excimer laser light (100 mJ / cm ² × 50 shots = 5,000 mJ / cm ² ), the resist film was baked on a hot plate at 115 ° C. for 90 seconds, and then developed with 2.38 mass% TMAH aqueous solution. As a result of dissolving and removing the unexposed portion of the resist film, a resist pattern similar to the reticle pattern was obtained.

The preferred embodiments of the present invention are as follows.
(Supplementary Note 1) An exposure unit that emits exposure light from the optical element and exposes the surface to be exposed imagewise, and a cleaning liquid is supplied so as to contact the optical element in an exposure apparatus, and the cleaning liquid supplies the cleaning liquid. And at least cleaning means for cleaning the optical element,
The cleaning liquid is at least one of ultrapure water containing a surfactant and functional water obtained by dissolving at least one selected from hydrogen, ozone and carbon dioxide in ultrapure water. Exposure equipment.
(Supplementary note 2) The exposure apparatus according to supplementary note 1, wherein the exposure is performed by immersion exposure.
(Additional remark 3) The exposure apparatus in any one of Additional remark 1 or 2 which has a suction means to attract | suck the washing | cleaning liquid after washing | cleaning.
(Supplementary note 4) The exposure apparatus according to any one of supplementary notes 1 to 3, wherein the cleaning liquid is functional water obtained by dissolving ozone in ultrapure water.
(Supplementary note 5) The exposure apparatus according to any one of supplementary notes 1 to 4, wherein cleaning of the optical element is performed each time exposure light is irradiated by one shot.
(Supplementary note 6) The exposure apparatus according to any one of supplementary notes 1 to 4, wherein cleaning of the optical element is performed every time one lot of exposure light is irradiated.
(Supplementary note 7) Any one of Supplementary notes 1 to 6, wherein the exposure light is at least one of ArF excimer laser light having a wavelength of 193 nm, F ₂ excimer laser light having a wavelength of 157 nm, and EUV having a wavelength of 5 to 15 nm. An exposure apparatus according to claim 1.
(Supplementary Note 8) An exposure process in which exposure light is emitted from an optical element that is an exposure light emission surface of an exposure unit, and imagewise exposure is performed on the surface to be exposed, and the optical element is brought into contact with the exposure element in an exposure apparatus. And a cleaning step of supplying the cleaning liquid to the optical element and cleaning the optical element with the cleaning liquid.
(Supplementary Note 9) In an exposure apparatus having an exposure unit that exposes an exposed surface in an imagewise manner, a cleaning liquid is supplied so as to contact an optical element that is an exposure light emitting surface of the exposure unit, and the cleaning liquid Including at least a cleaning step of cleaning the optical element;
The cleaning liquid is at least one of ultrapure water containing a surfactant and functional water obtained by dissolving at least one selected from hydrogen, ozone and carbon dioxide in ultrapure water. Cleaning method for optical element.
(Supplementary note 10) The optical element cleaning method according to supplementary note 9, wherein the exposure is performed by immersion exposure.
(Additional remark 11) The cleaning method of the optical element in any one of Additional remark 9 to 10 including the suction process which attracts | sucks the washing | cleaning liquid after washing | cleaning.
(Supplementary note 12) The method for cleaning an optical element according to any one of supplementary notes 9 to 11, wherein the cleaning liquid is functional water obtained by dissolving ozone in ultrapure water.
(Supplementary note 13) The optical element cleaning method according to any one of supplementary notes 9 to 12, wherein the optical element is cleaned each time exposure light is irradiated by one shot.
(Supplementary note 14) The optical element cleaning method according to any one of supplementary notes 9 to 12, wherein the cleaning of the optical element is performed every time one lot of exposure light is irradiated.
(Supplementary note 15) Any of Supplementary notes 9 to 14, wherein the exposure light is at least one of ArF excimer laser light having a wavelength of 193 nm, F ₂ excimer laser light having a wavelength of 157 nm, and EUV having a wavelength of 5 to 15 nm. A method for cleaning an optical element according to claim 1.
(Supplementary Note 16) In an exposure apparatus having an exposure unit that exposes an exposed surface in an imagewise manner, a cleaning liquid is supplied so as to contact an optical element that is an exposure light exit surface of the exposure unit, and the cleaning liquid Comprising at least cleaning means for cleaning the optical element;
The cleaning liquid is at least one of ultrapure water containing a surfactant and functional water obtained by dissolving at least one selected from hydrogen, ozone and carbon dioxide in ultrapure water. Cleaning device for optical elements.

The exposure apparatus of the present invention can be suitably used for forming a fine and high-definition resist pattern. Examples of the resist pattern include a mask pattern, a reticle pattern, a magnetic head, an LCD (liquid crystal display), and a PDP (plasma display). Panel), functional parts such as SAW filters (surface acoustic wave filters), optical parts used for connecting optical wiring, fine parts such as microactuators, and electronic devices such as semiconductor devices. The electronic device can be suitably used in the field of various semiconductor devices including flash memory, DRAM, FRAM, thin film magnetic head, and the like.
According to the optical element cleaning method of the present invention, in an exposure apparatus using projection exposure, particularly an immersion exposure method, cleaning is performed in situ without removing the optical element in the exposure apparatus, and contaminants adhering to the optical element are removed. It can be suitably used for removal.

FIG. 1 is a schematic explanatory view showing an example of an exposure apparatus of the present invention. FIG. 2 is a schematic explanatory view showing an example of the exposure apparatus of the present invention, and shows aspects of the cleaning means and the suction means. FIG. 3 is a schematic explanatory view showing an example of the exposure apparatus of the present invention, and shows a mode in which a cleaning processing area is provided and cleaning is performed in the cleaning processing area. FIG. 4 is a schematic explanatory view showing an example of the exposure apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exposure apparatus 2 Projection lens (optical element)
3 Exposure means 4 Wafer stage 5 Object to be exposed (substrate)
6 Illumination optical system 7 Reticle 8 Medium (liquid)
10 Cleaning liquid jetting device (cleaning means)
12 Washing liquid container 14 Jet nozzle 20 Washing liquid suction device (suction means)
DESCRIPTION OF SYMBOLS 22 Cleaning liquid collection device 24 Suction nozzle 30 Exposure apparatus 40 Exposure apparatus 42 Liquid container 43 Cleaning liquid container 44 Spray nozzle (cleaning means)
45 Liquid recovery device 46 Cleaning fluid recovery device 47 Suction nozzle (suction means)
L Cleaning liquid S Cleaning area

Claims (5)

An exposure unit that emits exposure light from the optical element and exposes the surface to be exposed imagewise, and a cleaning liquid is supplied so as to contact the optical element in an exposure apparatus, and the optical element is cleaned with the cleaning liquid. And at least cleaning means for
The cleaning liquid is at least one of ultrapure water containing a surfactant and functional water obtained by dissolving at least one selected from hydrogen, ozone and carbon dioxide in ultrapure water. Exposure equipment.   The exposure apparatus according to claim 1, wherein the exposure is performed by immersion exposure.   The exposure apparatus according to claim 1, further comprising a suction unit that sucks the cleaning liquid after cleaning.   4. An exposure apparatus according to claim 1, wherein the cleaning liquid is functional water obtained by dissolving ozone in ultrapure water. In an exposure apparatus having an exposure unit that exposes the surface to be exposed imagewise, a cleaning liquid is supplied so as to contact an optical element that is an exposure light exit surface of the exposure unit, and the optical element is moved by the cleaning liquid. Including at least a cleaning step for cleaning,
The cleaning liquid is at least one of ultrapure water containing a surfactant and functional water obtained by dissolving at least one selected from hydrogen, ozone and carbon dioxide in ultrapure water. Cleaning method for optical element.

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