JP2009141050A - Cleaning liquid and cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide cleaning liquid which has high security and is superior in cleaning performance and to provide a cleaning method using cleaning liquid. <P>SOLUTION: Cleaning liquid which contains (a) surfactant and (b) lactone solvent and whose content of (b) lactone solvent is not less than 60 wt.% is used as that for cleaning a liquid immersion exposure device filling a space between an optical lens part and an object of exposure, which is placed on a wafer stage, with a liquid immersion medium and performing exposure. Cleaning liquid may contain the (c) liquid immersion medium, (d) water-soluble organic solvent and (e) hydrocarbon solvent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cleaning liquid used in a liquid immersion lithography process and a cleaning method using the same.

  Photolithography is frequently used in the production of fine structures in various electronic devices such as semiconductor devices and liquid crystal devices. In recent years, the progress of high integration and miniaturization of semiconductor devices has been remarkable, and further miniaturization is required in forming a photoresist pattern in a photolithography process.

In order to achieve such finer pattern formation, generally, countermeasures by improving the exposure apparatus and the photoresist material can be considered. Measures by exposure equipment include shortening the wavelength of light sources such as F ₂ excimer laser, EUV (extreme ultraviolet light), electron beam, X-ray, soft X-ray, and increasing the numerical aperture (NA) of the lens. Measures are listed.

  However, shortening the wavelength of the light source requires an expensive new exposure apparatus. In addition, when the NA is increased, the resolution and the depth of focus are in a trade-off relationship, so that there is a problem that the depth of focus decreases even if the resolution is increased.

  In recent years, an immersion exposure process has been reported as a photolithography technique that can solve such a problem (for example, see Non-Patent Documents 1 to 3). This is because, during exposure, an immersion medium having a predetermined thickness on at least the photoresist film in the exposure optical path between the optical lens unit of the exposure apparatus and the exposure object (photoresist film on the substrate) placed on the wafer stage. The photoresist film is exposed through a film to form a photoresist pattern. In this immersion exposure process, the exposure optical path space, which has conventionally been an inert gas such as air or nitrogen, has a refractive index that is larger than the refractive index of these spaces (gas) and smaller than the refractive index of the photoresist film. Even if a light source with the same exposure wavelength is used by replacing it with an immersion medium (for example, water or a fluorine-based inert liquid), a shorter wavelength exposure light or a high NA lens is used. In the same way as above, there is an advantage that a high resolution is achieved and a reduction in the depth of focus does not occur.

  By using such an immersion exposure process, it is possible to form a photoresist pattern that is low in cost, excellent in high resolution, and excellent in depth of focus, using a lens mounted on an existing exposure apparatus. Therefore, it is attracting a lot of attention.

  However, in the immersion exposure process, since exposure is performed with an immersion medium interposed in the upper layer of the photoresist film, damage to the exposure apparatus due to elution components from the photoresist film (for example, fogging of the lens glass material and There is a concern that the transmittance may be reduced due to the occurrence of exposure unevenness.

  As countermeasures against this, measures have been taken to improve the photoresist material to prevent elution from the photoresist film, and to provide a protective film on the photoresist layer to prevent exudation of the eluted components from the photoresist film. ing. However, the former method has limitations in development from the viewpoint of the photoresist material, and there is a problem that it is difficult to apply the photoresist material to a wide range of uses. In addition, the latter method still cannot completely prevent the elution of the eluted components. Further, in any method, when the photoresist film or its protective film is partially peeled and adheres to the optical lens portion, damage to the exposure apparatus is inevitable.

  Therefore, a method for cleaning the optical lens portion of the exposure apparatus that contacts the immersion medium using a cleaning liquid has been proposed as a measure for solving the above problems by using a photoresist film and a protective film that are currently widely used. (For example, refer to Patent Document 1).

However, since the cleaning liquid described in Patent Document 1 is composed of a ketone-based or alcohol-based organic solvent, there is a risk of ignition, and there is a restriction that prevents ignition in the configuration of the handling and exposure apparatus. Arise. In addition, these organic solvents do not have a sufficient cleaning effect, especially when the photoresist film or its protective film is partially peeled off and adheres to the optical lens part, and the cleaning is difficult, and the optical characteristics of the exposure apparatus are There is a risk of deterioration.
"Journal of Vacuum Science & Technology B", (USA), 1999, Vol. 17, No. 6, pp. 3306-3309 "Journal of Vacuum Science & Technology B", (USA), 2001, Vol. 19, No. 6, pp. 2353-2356 “Proceedings of SPIE” (USA), 2002, 4691, pages 459-465. JP 2005-79222 A

  The present invention has been made in view of such a conventional situation, and an object of the present invention is to provide a cleaning liquid having high safety and excellent cleaning performance, and a cleaning method using the same.

  In order to solve the above-mentioned problems, the present inventors have conducted extensive research. As a result, it has been found that the above problem can be solved by containing a predetermined amount or more of a lactone solvent in the cleaning liquid, and the present invention has been completed. Specifically, the present invention provides the following.

  A first aspect of the present invention is a cleaning liquid used for cleaning an immersion exposure apparatus that performs exposure by filling an immersion medium between an optical lens unit and an exposure object placed on a wafer stage. (A) A surfactant and (b) a lactone solvent, and the content of the (b) lactone solvent is 60% by mass or more.

  According to a second aspect of the present invention, an immersion exposure apparatus including at least an optical lens unit, a wafer stage, a liquid introduction flow path, and a liquid discharge flow path is used. An immersion exposure process in which exposure is performed while the immersion medium is introduced and filled through the liquid introduction flow path while the immersion medium is discharged through the liquid discharge flow path between the exposure object placed on the exposure object. Then, after the exposure, the cleaning liquid according to the present invention is introduced through the liquid introduction flow path, the cleaning liquid is cleaned by contacting the optical lens portion for a predetermined time, and the used cleaning liquid is discharged through the liquid discharge flow path. This is a cleaning method.

  According to a third aspect of the present invention, a liquid immersion exposure apparatus including at least an optical lens unit and a wafer stage is used, and a liquid immersion is performed between the optical lens unit and an exposure object placed on the wafer stage. In an immersion exposure process in which exposure is performed by filling with a medium, after exposure, the optical lens unit is sprayed with a cleaning liquid according to the present invention or the optical lens unit is wiped with a cloth exposed to the cleaning liquid. The cleaning method is characterized in that the part is cleaned.

  According to the present invention, a cleaning liquid having high safety and excellent cleaning performance and a cleaning method using the same are provided.

≪Cleaning liquid≫
The cleaning liquid according to the present invention contains (a) a surfactant and (b) a lactone solvent. This cleaning liquid is used for cleaning an immersion exposure apparatus that performs exposure by filling an immersion medium between an optical lens unit and an exposure object placed on a wafer stage. Hereinafter, each component contained in the cleaning liquid will be described in detail.

[(A) Surfactant]
The cleaning liquid according to the present invention contains a surfactant. By containing this surfactant, the permeability of the cleaning liquid itself can be improved and the cleaning performance can be improved.

  As the surfactant, a nonionic surfactant can be preferably used. As such nonionic surfactants, polyoxyalkylene compounds and sorbitan fatty acid compounds are preferable, and among them, polyoxyalkylene alkyl ether, polyoxyalkylene alkyl phenyl ether, polyoxyalkylene alkyl fatty acid ester, polyoxyalkylene At least one selected from allyl phenyl ether, polyoxyalkylene sorbitan fatty acid ester, sorbitan fatty acid ester, and polyoxyalkylene is preferable.

  Examples of polyoxyalkylene include polyoxyethylene, polyoxypropylene, polyoxybutylene and the like. The added mole number of polyoxyalkylene is preferably adjusted so that the average added mole number is in the range of 1 to 50 moles.

  The alkyl group constituting the terminal etherified product of polyoxyalkylene is preferably one having 6 to 18 carbon atoms. Specific examples include hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, detradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group and the like. This alkyl group may be branched or cyclic (either a single ring or a complex ring), may have an unsaturated bond, and a part of the hydrogen atoms may be alcohol. It may be substituted with a functional hydroxyl group.

  The fatty acid is not particularly limited, and examples thereof include heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid and the like.

  This polyoxyalkylene compound and sorbitan fatty acid compound are commercially available as a series such as “New Coal” (manufactured by Nippon Emulsifier Co., Ltd.), and these can be preferably used.

  Moreover, as a nonionic surfactant, an acetylene alcohol type compound can also be used. As the acetylene alcohol compound, for example, a compound represented by the following general formula (1) is preferable.

（上記一般式（１）中、Ｒ_１は水素原子、又は下記式（２）

で表される基を示し、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５はそれぞれ独立に水素原子、又は炭素数１〜６のアルキル基を示す。）

(In the general formula (1), R ₁ is a hydrogen atom, or the following formula (2)

R ₂ , R ₃ , R ₄ and R ₅ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. )

  This acetylene alcohol-based compound is commercially available as a series such as “Surfinol” and “Orphine” (both manufactured by Air Products), and these can be preferably used. Among these, “Surfinol 104”, “Surfinol 82”, or a mixture thereof is preferable from the viewpoint of physical properties. In addition, “Olfin B”, “Olfin P”, “Olfin Y” and the like can be used.

  Moreover, as a nonionic surfactant, the compound which added the alkylene oxide to the said acetylene alcohol can also be used. As the alkylene oxide to be added, ethylene oxide, propylene oxide, or a mixture thereof is preferable. As the acetylene alcohol / alkylene oxide adduct, a compound represented by the following general formula (3) is preferable. Here, (n + m) represents an integer of 1 to 30, and characteristics such as solubility in water and surface tension slightly change depending on the number of additions of ethylene oxide.

（上記一般式（３）中、Ｒ_６は水素原子、又は下記式（４）

で表される基を示し、Ｒ_７、Ｒ_８、Ｒ_９、Ｒ_１０はそれぞれ独立に水素原子、又は炭素数１〜６のアルキル基を示す。）

(In the above general formula (3), R ₆ is a hydrogen atom, or the following formula (4)

R ₇ , R ₈ , R ₉ and R ₁₀ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. )

  This acetylene alcohol / alkylene oxide adduct is commercially available as a series such as “Surfinol” (manufactured by Air Products), “acetylenol” (manufactured by Kawaken Fine Chemical Co., Ltd.), and these can be preferably used. Among them, in consideration of changes in water solubility, surface tension and other properties due to the number of ethylene oxide added, “Surfinol 440” (n + m = 3.5), “Surfinol 465” (n + m = 10), “Surfinol 485” (n + m = 30), “acetylenol EL” (n + m = 4), “acetylenol EH” (n + m = 10), or a mixture thereof is preferable.

  As the surfactant, in addition to the nonionic surfactant, various cationic surfactants and anionic surfactants can be used as long as the stability of the cleaning liquid and the cleaning performance are not adversely affected.

  The content of the surfactant is preferably 0.01% by mass to 5% by mass, and more preferably 0.1% by mass to 3% by mass in the cleaning liquid. By setting the content of the surfactant within the above range, it is possible to improve the cleaning performance while avoiding problems due to separation of the cleaning liquid and the like.

[(B) Lactone solvent]
The cleaning liquid according to the present invention contains a lactone solvent. Since the cleaning performance is improved by including this lactone solvent, a photoresist film, a protective film or the like is attached to an immersion exposure apparatus, particularly a part (optical lens part, etc.) where the immersion medium comes into contact. These can be removed quickly.

  The lactone solvent is not particularly limited, but γ-butyrolactone, α-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-laurolactone, δ-valerolactone, hexanolactone, etc. Is mentioned. Among these, from the viewpoint of cleaning performance, water solubility, and availability, γ-butyrolactone, α-methyl-γ-butyrolactone, and γ-valerolactone are preferable, and γ-butyrolactone is particularly preferable.

  The content of the lactone solvent is 60% by mass or more in the cleaning liquid, and preferably 80% by mass or more. By setting the content of the lactone solvent in the above range, the cleaning performance can be improved.

[(C) Immersion medium]
The cleaning liquid according to the present invention may further contain an immersion medium used in the immersion exposure process. By including this immersion medium, the replacement efficiency when substituting with the immersion medium is improved, so that the time required for stopping the immersion exposure apparatus during the cleaning operation can be shortened, and the throughput of semiconductor manufacturing is greatly reduced. You do n’t have to.

The immersion medium is not particularly limited as long as it is a liquid having a refractive index larger than the refractive index of air and smaller than the refractive index of the photoresist film (exposure target) to be used. As such an immersion medium, water (pure water, deionized water), a liquid in which various additives are added to water to increase the refractive index, a fluorine-based inert liquid, a silicon-based inert liquid, a hydrocarbon-based liquid An immersion medium having a high refractive index characteristic, which is expected to be developed in the near future, can be used. Examples of the fluorine-based inert liquid include liquids mainly composed of fluorine-based compounds such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F _7. It is done. Among these, water (pure water, deionized water) is preferable when using exposure light (ArF excimer laser, etc.) having a wavelength of 193 nm from the viewpoint of cost, safety, environmental problems, and versatility. When using exposure light having a wavelength (such as F ₂ excimer laser), a fluorine-based inert solvent is preferable.

  When the immersion medium is contained, the content thereof is preferably less than 40% by mass in the cleaning liquid, and more preferably 1% by mass to 20% by mass. By setting the content of the immersion medium in the above range, it is possible to effectively improve the replacement efficiency when replacing with the immersion medium without deteriorating the cleaning performance. If the amount of the immersion medium is too large, the cleaning liquid itself may become cloudy, which may be undesirable as a cleaning liquid.

[(D) Water-soluble organic solvent]
The cleaning liquid according to the present invention may further contain a water-soluble organic solvent. By containing this water-soluble organic solvent, the stability of the cleaning liquid can be improved and the cleaning performance can be further improved. The water-soluble organic solvent is preferably at least one selected from alkanolamines, alkylamines, polyalkylenepolyamines, glycols, ethers, ketones, acetates, and carboxylic acid esters.

  Examples of alkanolamines include monoethanolamine, diethanolamine, triethanolamine, 2- (2-aminoethoxy) ethanol [= diglycolamine], N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-methyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine and the like can be mentioned.

  Examples of the alkylamines include 2-ethyl-hexylamine, dioctylamine, tributylamine, tripropylamine, triallylamine, heptylamine, cyclohexylamine and the like.

  Examples of polyalkylene polyamines include diethylenetriamine, triethylenetetramine, propylenediamine, N, N-diethylethylenediamine, N, N′-diethylethylenediamine, 1,4-butanediamine, N-ethyl-ethylenediamine, and 1,2-propanediamine. 1,3-propanediamine, 1,6-hexanediamine and the like.

  Examples of glycols include ethylene glycol, diethylene glycol, propylene glycol, glycerin, 1,2-butylene glycol, 1,3-butylene glycol, and 2,3-butylene glycol.

  Examples of ethers include ethylene glycol monomethyl ether [= methyl cellosolve], ethylene glycol monoethyl ether [= ethyl cellosolve], ethylene glycol diethyl ether, ethylene glycol isopropyl ether, ethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, propylene Examples include glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether [= butyl diglycol], diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, benzyl ethyl ether, and dihexyl ether. .

  Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, diisopropyl ketone, cyclobutanone, cyclopentanone, and cyclohexanone.

  Acetates include ethylene glycol monomethyl ether acetate (= methyl cellosolve acetate), ethylene glycol monoethyl ether acetate (= ethyl cellosolve acetate), ethylene glycol mono-n-butyl ether acetate (= n-butyl cellosolve acetate), propylene glycol monomethyl ether Examples include acetate.

  Examples of the carboxylic acid esters include alkyl- or aliphatic-carboxylic acid esters, monooxycarboxylic acid esters, and the like. Specifically, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, Examples include amyl acetate and isoamyl acetate.

  Among these, alkanolamines, glycols, ethers, ketones, acetates, and carboxylic acid esters are preferable.

  When the water-soluble organic solvent is contained, the content thereof is preferably 0.1 mass ppm to 20 mass%, more preferably 1 mass% to 8 mass% in the cleaning liquid. By setting the content of the water-soluble organic solvent in the above range, the stability of the cleaning liquid can be improved and the cleaning performance can be further improved.

[(E) Hydrocarbon solvent]
The cleaning liquid according to the present invention may further contain a hydrocarbon solvent. By containing this hydrocarbon solvent, it is possible to improve the cleaning performance for the components eluted from the photoresist film. As the hydrocarbon solvent, alkanes and alkenes can be widely used. Among them, straight chain or branched chain alkanes having 8 to 12 carbon atoms, straight chain having 8 to 12 carbon atoms, At least one selected from branched alkenes and terpenes is preferred.

  As the linear or branched alkanes having 8 to 12 carbon atoms and the linear or branched alkenes having 8 to 12 carbon atoms, commercially available ones can be used. Among these, n-decane and 1-decene are preferable from the viewpoint of cleaning performance.

  As the terpenes, monoterpenes, diterpenes and the like are preferable. Monoterpenes include geraniol, nerol, linalool, citral, citronellol, p-menthane, diphenylmenthane, menthol, isomenthol, neomenthol, limonene, dipentene, terpineol, carvone, yonon, tunon, camphor, bornane, borneol, norbornane. , Pinane, α-pinene, β-pinene, tujan, α-tujon, β-tujon, caran, camphor, α-terpinene, β-terpinene, γ-terpinene, and the like. Examples of diterpenes include abietane and abietic acid. Monoterpenes are preferable from the viewpoint of availability, and among them, at least one selected from limonene, pinene, and p-menthane is preferable because of high cleaning performance.

  When the hydrocarbon-based solvent is contained, the content thereof is preferably 0.01% by mass to 5% by mass and more preferably 0.1% by mass to 2% by mass in the cleaning liquid. By setting the content of the hydrocarbon solvent in the above range, the cleaning performance can be further improved.

≪Exposure and development method≫
For example, the exposure method in the immersion exposure process and the subsequent development method are as follows.

  First, as an exposure object, a conventional photoresist composition is applied onto a substrate such as a silicon wafer by a spinner or the like, and then pre-baked to form a photoresist film. The photoresist film may be formed after providing an organic or inorganic antireflection film (lower antireflection film) on the substrate. Further, a protective film may be formed on the surface of the photoresist film.

  The photoresist composition is not particularly limited, and any photoresist composition that can be developed with an alkaline aqueous solution, including negative and positive photoresist compositions, can be used. Examples of such a photoresist composition include (i) a positive photoresist composition containing a naphthoquinone diazide compound and a novolak resin, (ii) a compound that generates an acid upon exposure, and increased solubility in an aqueous alkali solution due to the action of the acid. And a positive photoresist composition containing an alkali-soluble resin, (iii) a compound that generates an acid upon exposure, and a positive photoresist containing an alkali-soluble resin having a group that increases the solubility in an aqueous alkali solution by the action of the acid. And (iv) a negative photoresist composition containing an acid or radical generating compound by light, a crosslinking agent, and an alkali-soluble resin.

  Next, the substrate on which the photoresist film is formed is placed on the wafer stage of the immersion exposure apparatus. As the immersion exposure apparatus, an optical lens unit is preferably disposed on the wafer stage so as to face each other at a predetermined interval, and further includes a liquid introduction flow path and a liquid discharge flow path.

  Subsequently, the immersion medium is introduced from one direction of the wafer stage through the liquid introduction flow path into the space between the optical lens portion and the substrate on which the photoresist film is formed, and at the same time, the liquid is discharged in the other direction of the wafer stage. The space is filled with the immersion medium while the immersion medium is discharged (sucked) through the flow path. In this state, the photoresist film is selectively exposed through the mask pattern.

The exposure light is not particularly limited, and radiation such as ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EB, EUV, VUV (vacuum ultraviolet) can be used. In addition, as described above, as the immersion medium, water (pure water, deionized water), a liquid in which various additives are added to water to increase the refractive index, a fluorine-based inert liquid, a silicon-based inert liquid Hydrocarbon-based liquids can be used.

  Here, in the local liquid immersion exposure method, the exposure lens is scanned and moved at high speed, and the immersion medium is continuously dropped onto the photoresist film from the liquid introduction nozzle (liquid introduction flow path). Then, the photoresist film on the substrate in the continuous dropping state is selectively exposed through a mask pattern. Excess immersion medium is discharged through a liquid discharge nozzle (liquid discharge channel).

  The exposure method is not limited to the local immersion exposure method, and the substrate on which the photoresist layer is formed may be immersed in an immersion medium for exposure.

  In any of the above methods, at least the space between the optical lens portion and the substrate on which the photoresist film is formed is filled with the immersion medium. The photoresist film on the substrate in this state is selectively exposed through a mask pattern. Therefore, the exposure light passes through the immersion medium and reaches the photoresist film.

  At this time, the constituent components of the photoresist film may elute into the immersion medium and adhere to the immersion exposure apparatus as contaminants. In addition, the photoresist film and its protective film may be partially peeled off and adhere to the immersion exposure apparatus as contaminants.

  When the exposure process in the immersion state is completed, the substrate is taken out of the immersion medium and the liquid is removed from the substrate.

  Subsequently, post-exposure heat treatment (PEB treatment) is performed on the exposed photoresist film, and further, development processing is performed using an alkaline developer composed of an alkaline aqueous solution. Any conventional alkali developer can be used. Subsequent to the development process, a post-bake process may be performed. Thereafter, rinsing is performed using pure water or the like. In this rinsing, for example, water is dropped or sprayed on the surface of the substrate while rotating the substrate to wash away the alkali developer on the substrate and the photoresist film (and the protective film) dissolved by the alkali developer. Then, by drying, a photoresist pattern in which the photoresist film is patterned into a shape corresponding to the mask pattern is obtained.

  By forming a photoresist pattern in this manner, a photoresist pattern with a fine line width, particularly a line-and-space pattern with a small pitch can be produced with good resolution.

≪Cleaning method≫
In the first cleaning method according to the present invention, after exposure, the cleaning liquid according to the present invention is introduced through a liquid introduction channel, and the cleaning liquid is cleaned by contacting the optical lens portion for a predetermined time. It is discharged through the discharge channel. Thus, by sharing the same flow path as that used for introducing and discharging the immersion medium, it is not necessary to provide a separate cleaning liquid flow path, and the manufacturing cost can be reduced.

  The contact time of the cleaning liquid to the optical lens portion is not particularly limited as long as it is sufficient to clean and remove the elution component of the photoresist film, the partially peeled and adhered photoresist film, and the protective film. Usually, it is about 30 seconds to 10 minutes. As a result, even if a photoresist film or a protective film adheres to the immersion exposure apparatus, particularly the optical lens unit, these can be removed quickly, so that a highly accurate exposure process is always in a clean state. Can be performed. In addition, this exposure makes it possible to form a highly reliable photoresist pattern.

  In addition, the second cleaning method according to the present invention cleans the optical lens part after exposure by spraying the cleaning liquid according to the present invention onto the optical lens part or wiping the optical lens part with a cloth exposed to the cleaning liquid. To do. Also by this method, it is possible to quickly remove the photoresist film, the protective film and the like attached to the optical lens portion.

  The cleaning method using the cleaning liquid according to the present invention is not limited to the above two types of methods.

  Hereinafter, the present invention will be described in detail with reference to examples. In addition, this invention is not limited to the following Example at all.

[Examples 1 to 24, Comparative Examples 1 to 18]
A photoresist composition (trade name: TArF-P6239ME, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to an 8-inch silicon substrate treated with hexamethyldisilazane (HMDS) (trade name: OAP, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 1500 rpm. And heated at 110 ° C. for 60 seconds to obtain a 200 nm thick photoresist film. The silicon substrate on which the photoresist film is formed is immersed in various cleaning solutions having the compositions shown in Tables 1 to 4 for 5 minutes, rinsed with deionized water for 30 seconds, and then dried by nitrogen blowing to confirm the solubility of the photoresist film. did. The results are shown in Tables 1 to 4.

  Further, a composition for forming a protective film (trade name: TILC-057, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied to an 8-inch silicon substrate treated with hexamethyldisilazane (HMDS) (trade name: OAP, manufactured by Tokyo Ohka Kogyo Co., Ltd.). Was applied at 1500 rpm and heated at 90 ° C. for 60 seconds to obtain a protective film having a thickness of 35 nm. The silicon substrate on which this protective film is formed is immersed in various cleaning solutions having the compositions shown in Tables 1 to 4 for 5 minutes, rinsed with deionized water for 30 seconds, and then dried by nitrogen blowing to confirm the solubility of the protective film. did. The results are shown in Tables 1 to 4.

In addition, the evaluation criteria of the cleaning effect in Tables 1 to 4 are as follows.
(Evaluation criteria)
○: Completely dissolved Δ: Incompletely dissolved ×: Not dissolved

Ｓ１：アセチレンアルコール・エチレンオキシド付加物（商品名：サーフィノール４８５、エアプロダクツ社製）
Ｓ２：ポリオキシエチレンステアリルエーテル（商品名：ニューコール１８２０、日本乳化剤社製）
ＧＢＬ：γ−ブチロラクトン
ＰＧＭＥ：プロピレングリコールモノメチルエーテル
ＢＤＧ：ブチルジグリコール

S1: Acetylene alcohol / ethylene oxide adduct (trade name: Surfynol 485, manufactured by Air Products)
S2: Polyoxyethylene stearyl ether (trade name: New Coal 1820, manufactured by Nippon Emulsifier Co., Ltd.)
GBL: γ-butyrolactone PGME: Propylene glycol monomethyl ether BDG: Butyl diglycol

  As can be seen from Tables 1 to 4, when the cleaning liquids of Examples 1 to 24 having a lactone solvent content of 60% by mass or more were used, both the photoresist film and the protective film were dissolved. In particular, when the cleaning liquids of Examples 1 to 12 having a lactone solvent content of 80% by mass or more were used, both the photoresist film and the protective film were completely dissolved. On the other hand, when the cleaning liquids of Comparative Examples 1 to 18 having a lactone solvent content of less than 60% by mass were used, the photoresist film did not dissolve and the protective film had poor solubility. From this result, even when the photoresist film or the protective film is partially peeled off and attached to the immersion exposure apparatus, the cleaning liquid according to the present invention in which the content of the lactone solvent is 60% by mass or more is used. Thus, it is considered that these can be removed promptly.

Claims (14)

A cleaning liquid used for cleaning an immersion exposure apparatus that performs exposure by filling an immersion medium between an optical lens unit and an exposure object placed on a wafer stage,
(A) a surfactant, and (b) a lactone solvent,
A cleaning liquid, wherein the content of the (b) lactone solvent is 60% by mass or more.   The cleaning liquid according to claim 1, wherein the surfactant (a) is a nonionic surfactant.   The cleaning liquid according to claim 1 or 2, wherein the (b) lactone solvent is at least one selected from γ-butyrolactone, α-methyl-γ-butyrolactone, and γ-valerolactone.   The cleaning liquid according to any one of claims 1 to 3, further comprising (c) an immersion medium.   The cleaning liquid according to claim 4, wherein the content of the (c) immersion medium is less than 40% by mass.   6. The cleaning liquid according to claim 4, wherein the immersion medium (c) is water.   The cleaning liquid according to claim 1, further comprising (d) a water-soluble organic solvent.   The (d) water-soluble organic solvent is at least one selected from alkanolamines, alkylamines, polyalkylenepolyamines, glycols, ethers, ketones, acetates, and carboxylic acid esters. The cleaning liquid according to claim 7.   The cleaning liquid according to claim 7 or 8, wherein the content of the (d) water-soluble organic solvent is 0.1 mass ppm to 20 mass%.   The cleaning liquid according to claim 1, further comprising (e) a hydrocarbon solvent.   The (e) hydrocarbon solvent is a linear or branched alkane having 8 to 12 carbon atoms, a linear or branched alkene having 8 to 12 carbon atoms, and terpenes. The cleaning liquid according to claim 10, wherein the cleaning liquid is at least one selected.   The cleaning liquid according to claim 10 or 11, wherein the content of the (e) hydrocarbon solvent is 100 mass ppm to 5 mass%.   Using an immersion exposure apparatus having at least an optical lens unit, a wafer stage, a liquid introduction channel, and a liquid discharge channel, the optical lens unit and an exposure object placed on the wafer stage In the immersion exposure process of performing exposure while introducing and filling the immersion medium through the liquid introduction flow path while discharging the immersion medium through the liquid discharge flow path, after exposure, The cleaning liquid according to any one of 12 is introduced through the liquid introduction flow path, the cleaning liquid is cleaned by contacting the optical lens unit for a predetermined time, and the used cleaning liquid is discharged through the liquid discharge flow path. A cleaning method characterized by the above.   Liquid immersion exposure is performed by using an immersion exposure apparatus including at least an optical lens part and a wafer stage, and performing exposure by filling an immersion medium between the optical lens part and an exposure object placed on the wafer stage. In the exposure process, after the exposure, the optical lens unit is sprayed on the optical lens unit with the cleaning liquid according to any one of claims 1 to 12, or the optical lens unit is wiped with a cloth exposed to the cleaning liquid. Cleaning method characterized by cleaning.