TW200804989A - Method for forming resist pattern - Google Patents

Abstract

A method of forming a resist pattern through the liquid immersion exposure step of irradiating a photoresist film in the presence of a liquid with refractive index higher than that of air (immersion liquid) with radiation to thereby attain exposure of the photoresist film, comprising forming the photoresist film on a substratum surface; forming a protective film resistant to the immersion liquid on the surface of the photoresist film; in the presence of the immersion liquid, irradiating the photoresist film with radiation to thereby attain exposure of the photoresist film; detaching the protective film from the surface of the photoresist film; and thereafter carrying out exposure, heating treatment and development, thereby obtaining a resist pattern.

Description

200804989 (1) Description of the Invention [Technical Field] The present invention relates to a method of forming a photoresist pattern suitable for use in the manufacture of integrated circuits. In particular, it is a method for forming a liquid/resist pattern of a lithography technique that can form a finer photoresist pattern. [Prior Art] In recent years, the miniaturization of integrated circuits has been made into a projection exposure apparatus for developing a circuit, and the resolution R and the focus are expressed by the following formula (i) and the following formula (ii) as the wavelength λ of the exposure light. The shorter the distance, the smaller the number of apertures of the projection lens n A, the smaller the resolution R (the minimum resolution size), the lower the resolution, the shorter the wavelength of the exposure light source and the number of projection openings in the projection exposure apparatus. get on. ❿ R = k1 · λ /NA : ( i) (5=k2·久/ΝΑ2 : (ii) (However, R: resolution, 5: set depth, A: exposure light, NA: number of openings of the projection lens, k 1 , k2 : processing coefficient) In addition, as a lithography technique for improving the resolution, a method is also known. The immersion exposure is a medium in which a refracting film is irradiated with a higher refractive index (liquid immersion liquid) than air. Let it be finely applied by using the solution immersion exposure. The set depth δ is the source of the large radiation, then the solution is high. Therefore, the high source wavelength of the lens 〇 liquid immersion exposure liquid of the photoresist film -5 - 200804989 (2 The method of exposure, that is, the space between the projection lens and the photoresist film which is filled with the liquid immersion liquid in a space filled with the projection lens and the photoresist film filled with air and nitrogen is usually The resolution R and the depth of focus 6 when the liquid immersion liquid having the refractive index η is full are expressed by the following formula (iii) and the following formula (iv). That is, the resolution R is obtained by using the liquid immersion liquid having the refractive index η. The minimum resolution size is 1 / η, which improves the resolution, plus the depth of focus · 6 is expanded and improved to η times. For example, when an ArF excimer laser (wavelength: 193 nm) is used as a light source, and water having a refractive index η of 1.4 4 in its wavelength is used as a liquid immersion liquid, Compared with the non-liquid immersion condition of air and nitrogen, the resolution R (minimum resolution size) is increased to 1/1.44 (69.4%), and the depth of focus 5 is expanded to 1.4 times. R = k 1 · ( λ / η ) / ΝΑ : (iii) 5 = k2 · ηλ / ΝΑ 2 : (iv) (however, n : refractive index ' with respect to R, d, λ, NA, k 1 , k 2 and equation (i) And the formula (ii) is synonymous.) The technique of such immersion exposure is microfabrication, especially for the lithography type of microfabrication in units of 1 〇 nm. It is considered to be a necessary method. A projection exposure apparatus for immersion exposure is disclosed (for example, refer to Patent Document 1). However, in the immersion exposure, since the liquid immersion liquid is in direct contact with the photoresist film -6 - 200804989 (3), the light-shielding film is immersed through the immersion film. The liquid immersion liquid causes an unpredictable chemical reaction and is pointed out to have an adverse effect on the photoresist performance (for example, refer to Patent Document 2) It is proposed to perform liquid immersion exposure in a state where a protective film having resistance to a liquid immersion liquid is formed on the surface of the photoresist film, and then, after the exposure, the protective film is peeled off to form a photoresist pattern (for example, Japanese Patent Laid-Open Publication No. Hei No. Hei. No. Hei. No. Hei. No. Hei. [Patent Document 4] Japanese Laid-Open Patent Publication No. Hei. No. 2005-264. The remaining liquid immersion liquid has a problem of residual defects in the resist pattern, defects in the water droplets (water mark defects), and a defect in which the width of the photoresist pattern becomes thick and conversely becomes thin (defective pattern defects). In other words, the photoresist pattern forming method described in Patent Documents 3 and 4 can be expected to form a high-resolution photoresist pattern, but it is still insufficient in terms of water mark defects and pattern defects. Satisfied, requires further improvement. As described above, in the present case, as a countermeasure against the occurrence of water mark defects and pattern defects, and the formation of a high-resolution photoresist pattern, the countermeasures have not been disclosed, and such countermeasures are urgently desired. The present invention is directed to solving the problems of the prior art described above, and is -7 - 200804989 (4) providing a photoresist pattern that effectively suppresses the occurrence of water mark defects and pattern defects, and forms a high resolution photoresist pattern. Forming method. The inventors of the present invention have found that after the exposure of the photoresist film protected by the liquid immersion liquid, and after the post-exposure heat treatment (PEB) in order to solve the results of the prior art review as described above, the film surface The present invention can be solved by preliminarily peeling off, and thereafter, by performing the post-exposure heating, the above problems can be solved. Specifically, the following method for forming a photoresist pattern. [1] A method for forming a photoresist pattern, which is characterized in that the resist film is irradiated with radiation by a liquid (liquid immersion liquid) having a higher refractive index than air, and the resist film can be exposed to immersion exposure. A method for forming a resist pattern, which is characterized in that a film is formed on a surface of the substrate, and a film is formed on the surface of the photoresist film for the liquid immersion liquid, and the photoresist is irradiated in a state in which the liquid immersion liquid is interposed. The photoresist film may be exposed, and the surface of the protective film m is peeled off, and then subjected to post-exposure heat treatment and development, and a pattern. [2] The method for forming a photoresist pattern according to the above [1], wherein the protective film is formed of a resin, and the front side is peeled off using an organic solvent. [3] The method for forming a photoresist pattern according to the above [2], wherein the lipophilic resin of the protective film is at least one selected from the group consisting of the following one I and the following general formula (2); The polymer acts as a constituent. Further, the shape-sensitive problem is to protect the film, and it is provided by photo-resistance and image-sensing, and the film-preserving film for the photoresistance of the light-lighting step is made of the light-receiving photoresist to provide a fat-soluble protective film. Forming the former J formula (1) repeat unit - 8- 200804989 (5) [Chemical 1]

CF3-P\ OH CF3 (1) (2) [However, in the general formula (1) or (2), R1 represents hydrogen, methyl or trifluoromethyl, and R2 represents a divalent organic group, R3 To represent an alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof]. The method for forming the photoresist pattern of the present invention is effective for suppressing the occurrence of water mark defects and pattern defects, and can form a high resolution photoresist pattern. [Embodiment] Hereinafter, a best mode for forming a photoresist pattern of the present invention will be specifically described. However, the present invention is an embodiment including all of the specific matters of the invention, and is not limited to the embodiments described below. In the present specification, the term "(meth)acrylate" means the concept of containing both acrylate or methacrylate. The method for forming the photoresist pattern of the present invention is a photoresist pattern having a liquid immersion exposure step of exposing the photoresist to a liquid having a higher refractive index than air (liquid immersion liquid), irradiating the photoresist film with radiation, and exposing the photoresist film. a method for forming a photoresist film on the surface of the substrate, and forming a protective film having a resistance to liquid immersion liquid on the surface of the photoresist film, and intervening the liquid immersion liquid and irradiating the radiation, The photoresist film is exposed, and the protective film is peeled off from the surface of the photoresist film, and then subjected to post-exposure heat treatment and development to form a photoresist pattern. Π] Formation of a photoresist film: * In the method for forming a photoresist pattern of the present invention, first, a photoresist film is formed on the surface of the substrate. Π-l] Substrate: The substrate is usually a germanium wafer, an aluminum-coated silicon wafer, or the like. In order to extract the characteristics of the photoresist film at the maximum limit, it is also preferable to form a film-based or inorganic anti-reflection film on the surface of the substrate in advance (for example, see Japanese Patent Publication No. Hei 6-22452). [1-2] Photoresist film (sensitive radioactive resin composition): • The type of the material for forming the photoresist film is not particularly limited, and may be appropriately selected and used according to the purpose of use of the photoresist, among the materials used for forming the photoresist film. can. However, in the method for forming a photoresist pattern of the present invention, a reinforced chemical resist material containing an acid generator is used, and a positive resist material is particularly preferable. The positive-type resistive material of the reinforced chemical type may, for example, be a radiation-sensitive resin composition containing an acid-dissociable base-modified alkali-soluble resin (component A) and a radiation-sensitive linear acid generator (component B) as essential components. Such a resin composition is an acid generated by an acid generator by radiation irradiation (exposure), -10- 200804989 (7) and by the action of an acid thereby, the acid group of the protective resin (for example, a carboxyl group) is dissociated. The base is dissociated to reveal an acidic group. Therefore, the alkali solubility of the photoresist exposed portion is increased, and the exposed portion is dissolved and removed via the alkali developing solution to form a positive resist pattern. [1-2A] Acid dissociable group-modified alkali-soluble resin (component A) The "acid-dissociable group-modified alkali-soluble resin" has an acidic group, and at least a part of the acidic group is protected by an acid-dissociable group. Resin. This resin exhibits an alkali-insoluble or alkali-insoluble property in a state in which at least a part of the acidic groups of the resin are protected by an acid-dissociable group. However, if the acid-dissociable group is dissociated by the action of an acid, the acidic group is exposed and displayed. An alkali soluble resin is obtained. In addition, the term "alkali-insoluble or alkali-insoluble" means light obtained from a radiation-sensitive resin composition containing an acid-dissociable group-modified alkali-soluble resin (component A) and a radiation-sensitive linear acid generator (component B). In the case where the film formed by the photoresist film is replaced by an acid-soluble modified alkali-soluble resin, the film is formed by the initial film of the film. 50% or more is a property remaining after development 〇* "Acid group" is not particularly limited as long as it is an acidic group. For example, a phenolic hydroxyl group, a carboxyl group or a sulfonic acid group may, for example, be mentioned. Among them, a phenolic hydroxyl group, a carboxyl group or the like is preferred for the reason that the effect of improving the solubility to alkali is high. The acid-dissociable group-modified alkali-soluble resin may have only one acidic group in it, and may have two or more kinds of acidic groups. -11 - 200804989 (8) The specific structure of the acid dissociable group which is contained in the component A is, for example, a repeating unit containing a skeleton represented by the following general formula (3) (hereinafter referred to as "repeated single k" (1) "Polymer as an essential component."

(3) [In the above general formula (3), 'R4 is a linear or a mixture of 4 to 20 one-valent alicyclic hydrocarbon groups or derivatives thereof, and a linear number of 4 carbon atoms, respectively. Further, the branched alkyl group and R4 may be bonded to each other, and an alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof may be formed. However, R4 is a structure containing at least one of the aforementioned alicyclic hydrocarbon groups or derivatives thereof, or R.4 which is bonded to each other to form an alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof. The component A is in the skeleton represented by the above general formula (3), and it is preferable to include a skeleton represented by the following general formulas (3a) to (3d).一 12- 200804989 (9) 3 Turn c=lo- R5 oR5

CIO

Q

oR5, II V / CIOIC

OR5 II CIO m

I (3b \^/ (3d [in the above general formula (3 a ) to (3 d ), R is a linear or branched alkyl group having the same or different carbon number of 1 to 4, m The structure of the main chain of the above repeating unit (1) is not particularly limited, but it is preferably a structure of (meth) acrylate or α-trifluoroacrylate. The specific unit of the above repeating unit (1) Constructed with 2-methyladamantyl-2-yl (meth)acrylate, 2 =ethyladamantyl-2-yl (meth)acrylate, 2-methylbicyclo(methyl)acrylate [ 2.2.1] Hept-2-yl ester, 2-ethylbicyclo[2.2_1]hept-2-yl (meth)acrylate, 1-(bicyclo[2.2.1]heptane-2(meth)acrylate -yl)-1-methylethyl ester, 1-(adamantan-1 -yl)-1-methylethyl (meth)acrylate, 1-methyl-1-cyclopentyl (meth)acrylate Ester, 1-ethyl-1-cyclopentyl (meth)acrylate, 1-methyl-1-cyclohexyl (meth)acrylate, 1-ethyl-1-cyclohexyl (meth)acrylate, etc. Preferably, at least a portion of the acidic group is protected by an acid-dissociable group - 13 - 200804989 (10) showing an alkali-insoluble or alkali The solubility is not particularly limited as long as it has a property of dissociating the acid dissociable group to expose an acidic group by an acid action and exhibiting alkali solubility. Therefore, the component A is not limited to a polymer containing a repeating unit (1). In the case of the resin used in such a use, it may be appropriately selected according to the purpose. * In the case where the component A is a repeating unit (1), it may be a monomer of a repeating unit (1), and Further, a copolymer of two or more kinds of repeating units (1) may be used, and a polymer having a repeating unit other than the repeating unit (1) may be used in addition to the repeating unit (1). The content of the repeating unit (1), Relatively speaking, all of the repeating units are usually 〇70% by mole, 15% to 60% by mole, and more preferably 20 to 50% by mole. The repeating unit (1) is more than 70 moles. %, the exposure margin may be deteriorated. Further, at least a part of the acidic groups of the polymer constituting the component A may be protected by the acid dissociable group, and all the acidic groups are not necessarily protected by the acid dissociable group. Dissociation The ratio of the introduction rate of the base (the ratio of the acid dissociable group of the acid group to the acid dissociable group in the polymer of the component A) is based on the type of the acid dissociable group and the polymerization as a base However, the introduction ratio is preferably in the range of 5 to 100%, and more preferably in the range of 10 to 100%. ^ The molecular weight range of the polymer constituting the component A is not particularly limited, and may be optionally required. The range of various molecular weights is determined. The mass average molecular weight (sometimes referred to as "Mw") converted into polystyrene measured by gel permeation chromatography (GPC) is usually 1,000 to 100, 〇〇〇, and is 1 , 〇〇〇 ~ 30,000 is better, with 1,000 ~ 20,000 as better. By making such a range, it is preferable to use -14-200804989 (11) to obtain a light resistance excellent in heat resistance and development. On the other hand, when the Mw of the polymer constituting the component A is less than 1, the heat resistance of the obtained photoresist tends to be insufficient. Further, if M w is more than 100 and 0 0 0, the development of the obtained photoresist may be lowered. In addition, the ratio (Mw/Mn) of the mass average molecular weight Mw converted to polystyrene to the number average molecular weight (may be described as "Μη") in terms of polystyrene measured by - GPC is not particularly limited. It can be made into a range of various molecular weights as needed. The enthalpy of Mw/Mn is usually from 1 to 5, and preferably from 1 to 3. By forming such a range, it is possible to obtain a photoresist having excellent resolution. [1-2B] Sensitive radioactive acid generator (component B): The "sensitizing radioactive acid generator" is an acid additive that induces radiation. The component B is an acid which generates an acid by radiation (exposure), and an acid generated therethrough dissociates the acid dissociable group of the acidic group (for example, a carboxyl group) of the protective resin, and the acidic group is exposed. Therefore, the alkali m solubility of the exposed portion of the photoresist is improved, and a positive resist pattern can be formed via alkali development. The structure of the component B is not particularly limited as long as it has the above properties. Therefore, it can be appropriately selected according to the purpose of the materials used in such applications. For example, an iron salt compound such as an iodine salt, a phosphonium salt, a scale salt, a diazo' iron salt or a pyridyl salt, a halogenated alkyl hydrocarbon compound, a haloalkyl group-containing heterocyclic compound or the like may be used. a compound, a 1,3 -diketo-2 -diazo compound, a diazonium phthalide compound, a diazonaphthene compound, or the like; a ketone maple, a sulfonium sulfonate, and the like A maple compound such as an α-diazo compound or a sulfonic acid compound. -15- 200804989 (12) Among them, an onium salt having a structure represented by the following general formula (4) is also preferred. 【化4】

R8 [In the above general formula (4), R6 is a linear or branched alkyl group having a hydrogen atom, a fluorine atom, a hydroxyl group, a carbon number of 1 to 10, or a linear or branched carbon number of 1 to 10. Alkoxy group, a linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms, and R 7 is a linear or branched alkyl group having 1 to 10 carbon atoms, an alkoxy group, and a carbon number of 1 to 1 0. One of a linear, branched, or cyclic alkanesulfonyl group, and r is an integer representing from 0 to 10. R8 is a linear or branched alkyl group having the same or different carbon number of 1 to 1 carbon atoms, and may be substituted phenyl or φ substituted naphthyl group, and R8 is bonded to each other to form a carbon number. 2 to 10 ring structures or derivatives thereof may also be used. k is an integer representing 0 to 2, R9 is a fluorine atom or a hydrocarbon group which may be substituted with 1 to 12 carbon atoms, and η is an integer representing 1 to 10]. The above-mentioned various acid generators may be used alone or in combination of two or more. The amount of the ruthenium component to be added is appropriately set according to the properties to be imparted to the photoresist, and is usually 0.1 to 20 parts by mass based on 1 part by mass of the bismuth component, and preferably 〇 5 to 10 parts by mass. . By forming such a range, it is possible to obtain a photoresist having excellent sensitivity and developability. On the other hand, if the blending amount of B is -16 - 200804989 (13) is less than 0.1 part by mass, the sensitivity and developability tend to be lowered. In addition, when it exceeds 20 parts by mass, the transparency 放射 of the radiation is lowered, and it is difficult to obtain a rectangular photoresist pattern. [1-2C] Additive: 'In the sensitive radiation linear resin composition, if necessary, additives other than the A component and the B component may be blended, for example, an acid diffusion inhibitor, an alicyclic additive having an acid φ dissociable group. , sensitizers, surfactants, etc. The "acid diffusion inhibitor" is an additive which suppresses the diffusion of an acid generated by an acid generator or the like in the photoresist film by exposure, and has an effect of suppressing a poor chemical reaction in the non-exposure field. By incorporating an acid diffusion inhibitor, the storage stability of the radiation sensitive resin composition can be improved. Further, by blending the acid diffusion inhibitor, the resolution of the photoresist can be improved, and the change in the line width of the resist pattern due to the change in the pull-in time (PED) until the development process is suppressed can be suppressed. As a result, it has a sensitive radiation linear resin composition which is excellent in handling stability. The acid diffusion inhibitor is preferably a nitrogen-containing organic compound which does not change to alkali by exposure and heat treatment in the formation step of the photoresist pattern. Examples of the nitrogen-containing organic compound include a tertiary amine compound such as an alkylamine, a cycloalkylamine, an aromatic amine, or an alkane alcoholamine, and a guanamine containing an N-tert-butoxycarbonyl group-based amine compound or the like. a compound of a base; a tetra-ammonium hydroxide compound such as tetra-n-propylammonium hydroxide or tetra-n-butylamine hydroxide; a nitrogen-containing heterocyclic compound such as a pyridine, a piperidine or an imidazole. Such an acid diffusion inhibitor may be used alone or in combination of two or more. -17- 200804989 (14) The amount of the acid diffusion inhibitor is usually 10 parts by mass or less, and preferably 0.001 to 10 parts by mass, and 0.005 to 5 parts by mass, based on 100 parts by mass of the component A. good. When the amount of the acid diffusion inhibitor is 10 parts by mass or less, the sensitivity as a photoresist and the development of the exposed portion can be improved. In addition, when the amount of the acid-diffusion inhibitor is 0.001 parts by mass or more, it is preferable to suppress the decrease in the shape and dimensional fidelity as a resist depending on the processing conditions. φ "The alicyclic additive having an acid-dissociable group" is a component which exhibits a further improvement in dry etching resistance, pattern shape, adhesion to a substrate, and the like. Examples of the alicyclic additive include adamantane derivatives such as 1-adamantanecarboxylic acid and 2-adamantanone; deoxycholate such as deoxycholic acid tert-butyl ester and deoxycholic acid third butoxycarbonyl methyl ester; Acid esters; tricholates such as tributyl cholesterate, tributyloxycarbonyl methyl trisulphate; alkyl carboxylates such as dimethyl adipate, diethyl adipate, etc. Class; 3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracyclo[4·4.0·12·5·17,10]dodecane and the like. _ The above alicyclic additive may be used alone or in combination of two or more. The blending amount of the above-mentioned alicyclic additive is preferably 5 parts by mass or less, and more preferably 30 parts by mass or less, based on 100 parts by mass of the bismuth component, from the viewpoint of improving the heat resistance of the photoresist. When the amount of the alicyclic additive is more than 50 parts by mass, the heat resistance of the photoresist is insufficiently sufficient. The "sensitizer" is an energy that absorbs radiation and transmits its energy to the component B, exhibits an effect of increasing the yield of the acid, and has an effect of improving the apparent sensitivity of the composition of the radioactive resin. -18- 200804989 (15) Examples of the sensitizer include oxazoles, acetophenones, benzophenones, naphthalenes, phenols, diacetamidines, anthracene-red, bengal roses, anthraquinones, anthraquinones, Phenothiazines and the like. These sensitizers may be used alone or in combination of two. The amount of the sensitizer is preferably 5 parts by mass or less based on 1 part by mass of the component A. The "surfactant" is a component that exhibits effects such as improved coatability, line traceability, and development. As the surfactant, any of an anionic, cationic φ, nonionic or amphoteric surfactant may be used, but a nonionic surfactant is preferably used. Examples of the nonionic surfactant include polyoxyethylene higher alkyl ethers, polyoxyethylene higher alkyl phenyl ethers, and higher fatty acid diesters of polyethylene glycol, and the following are commercially available under the trade name "KP" ( "Shin-Etsu Chemical Co., Ltd.", "Polyflow" (manufactured by Kyoei Oil & Fat Chemical Industry Co., Ltd.), "Efutop" (manufactured by TokemProdncts Co., Ltd.), "Megafac" (made by Dainippon Ink Chemical Industry Co., Ltd.), r Fl〇ride" (Sumitomo Each series such as "3M company", "Asahignard" and "Sufuron" (_ Asahi Glass Co., Ltd.). These surfactants may be used alone or in combination of two or more. The blending amount of the surfactant is preferably 1 part by mass or less based on the total resin component in the radiation sensitive resin composition, and is preferably 1.5 parts by mass or less, and 1 part by mass or less. Better. In the radiation-sensitive linear resin composition, in order to visualize the latent image of the exposed portion and to alleviate the blooming effect during exposure, a dye and a pigment may be blended, and a tackifier may be blended for the purpose of improving the adhesion to the substrate. In addition to the above additives, anti-corona agents, storage stabilizers, and antifoaming agents may also be cited. -19- 200804989 (16)

[1-2D] Solvent: In addition to the components A and B, the solvent may be blended with the solvent. The coating property when the radiation sensitive linear resin composition is applied to the substrate is high through the compounding solvent. The type of the "solvent" is not particularly limited, and examples thereof include a linear or branched ketone such as 2/3-methyl-2-butanone; and a cyclic ketone such as cyclopentanonecyclopentanone; a monoalkyl ether acetate such as propylene glycol monomethyl ether acetate; 2-hydroxypropionic acid such as 2-hydroxypropyl methyl ester; and 3-alkoxypropionic acid alkyl ester such as methyl 3-methoxypropionate Excluding r-butyrolactone and the like. These solvents may be used alone to form a mixture of two [1-3] photoresist films: the photoresist film is, for example, a component A, a component B, various additives, 0 solvent, and the total solid concentration is adjusted to 5 to 50 mass. %, and about 3 Onm filter paper This solution is filtered to prepare a coating liquid, and the liquid can be formed by coating the liquid on a substrate by a conventionally known method such as rotary coating, flow coating, roll coating, or the like. This resist film may be subjected to preliminary calcination (hereinafter, referred to as "PB") in order to allow the solvent to be used. When the photoresist film is formed, the coating liquid can be self-modulated, and a barrier solution can also be used as the coating liquid. [2] Formation of protective film: Ingredients, but can be butanone, 3-methylpropanediol alkyl ester, can be listed as 0 in the coating with the pore size of the coating volatilization, in addition, sold in the light -20- 200804989 (17) The method of the present invention is to form a protective film having resistance to a liquid immersion liquid after forming a photoresist film as described above. Through the exposure of the liquid immersion liquid, the liquid immersion liquid and the photoresist film are prevented from effectively preventing the lithographic performance of the photoresist film due to the immersion of the liquid immersion*. Effectively preventing the component eluted by the photoresist film from contaminating the projection exposure device* situation. The protective film is formed of a resin which can be formed into a liquid immersion liquid (for example, a film of I, which can be easily peeled off after immersion exposure. Further, "the liquid immersion liquid refers to the stability of water according to the following. The evaluation method is within 3% of the initial film thickness. [Stability evaluation test] (1): Use C 〇ater / D eve 1 ο per ( 1 ) CLEAN TRACK ACT8, φ wafer made by Tokyo Electron Co., Ltd. A coating liquid for a protective film (which is formed into a solvent) was spin-coated, and a protective film having a film thickness of 90 nm was formed at 90 ° C for 60 seconds PB. The light was disturbed (trade name: λ SVM- 2010, Dainippon Screen * Determine the protective film (initial film thickness). (2): Secondly, after the cleaning nozzle of the Coater/Developer (1) wafer forming the protective film is made of ultrapure water, the number of revolutions is 4000 rpm. The vibration is opened for 15 seconds, and the film thickness of the protective film is measured again, and the protective film is formed on the resist film surface to form a protective film, which is directly contacted, and can be lowered, and the lens can be stabilized by pure water or the like. Good, Tong'an Ding' In the case of (product name: ), the film thickness measurement was carried out under the conditions of a resin-melting clock for a film of 8 )), and the film thickness of the surface was rotated by the above-described discharge for 60 seconds (-21 - 200804989 (18) Reduced film thickness). When the ratio of the film thickness which is reduced by the film thickness is within 3%, it is evaluated as "the stability of the liquid immersion liquid". The resin forming the protective film (the resin for forming the protective film) is not particularly limited as long as it has the above properties. Therefore, the resin for forming the protective film can be selected from the resins previously used in such applications, depending on the purpose. However, in the method of the present invention, a fat-soluble resin is preferably used as the resin for forming a protective film. When the protective film φ is formed of a fat-soluble resin, the protective film can be peeled off using an organic solvent, and after the liquid immersion exposure, only the protective film can be peeled off before the alkali image is developed. That is, since the protective film is peeled off after the post-exposure heat treatment and development, it is possible to effectively prevent water mark defects and pattern defects caused by the protective film impregnation liquid immersion liquid. Further, the fat-soluble resin may be a resin soluble in alkali as long as it has solubility in an organic solvent. The fat-soluble resin is preferably a resin containing, as a constituent component, a polymer having at least one repeating unit selected from the group consisting of the following general formula (1) and the following general formula (2). These resins have a trifluoromethyl group and an alicyclic hydrocarbon group having 4 to 20 carbon atoms in the structure, so that a protective film which is resistant to pure water which is widely used as a liquid immersion liquid can be formed, and Since it has high fat solubility, it can be easily peeled off, for example, by an organic solvent such as a higher alcohol, a polyhydric alcohol, an alkyl acetate, or an alkyl ether. -22 - 200804989 (19) 【化5】 R1

+CH 2·

(2) (1) [However, in the general formula (1) or (2), R1 represents hydrogen, methyl or trifluoromethyl, R2 represents a divalent organic group, and R3 represents a carbon number of 4~ 20 alicyclic hydrocarbon groups or derivatives thereof. In the general formula (1), the "divalent organic group" represented by R2 may, for example, be a hydrocarbon such as a divalent hydrocarbon group, an alkylene glycol group or an alkyl ester group, and may contain a carbon atom or an atom other than a hydrogen atom. The divalent organic group and the like. Among them, a linear, branched or cyclic divalent hydrocarbon group is preferred, and a linear or branched saturated hydrocarbon group, a monocyclic hydrocarbon ring group or a crosslinked cyclic hydrocarbon ring group is preferred. a linear or branched saturated hydrocarbon group" is a methylene group, an extended ethyl group, a 1,2-propyl group, a 1,3-propanyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, Stretching octyl, stretching base, stretching base, stretching - alkyl, stretching 12 yards, stretching tridecyl, stretching tetradecyl, stretching pentadecyl, stretching 16 yards, stretching ten a linear chain of pentaalkyl, octadecyl or hexadecyl, 1-methyl-1,3-propanyl, 2-methyl-1,3-propanyl, a branched alkyl group of 2-methyl-i, 2_ propyl, 1-methyl-1,4-butyl or 2-methyl-1,4-butylene; ethylene, arylene The sub-base of propyl or 2-propylene, etc. is -23- soil..... mouth 200804989 (20) suitable. The "monocyclic hydrocarbon ring group" is a condensed alkyl group having 3 to 10 carbon atoms, specifically, a 1,3-cyclopentene butyl group, a 1,3-cyclopentylene group, and a 1,4-stretched ring. Hexyl, l,5-cyclohexyl group and the like are suitable. "Crosslinked cyclic hydrocarbon ring group" is a hydrocarbon ring group having 4 to 30 carbon atoms* and a number of rings of 2 to 4, specifically, 1,4-extension borneol, 2,5-extension An borneol base such as a borneol base; a stretched adamantyl group such as 1,5-adamantyl, 2,6-adamantyl or the like is suitable. φ "Divalent organic group" can also be combined with such functional groups. For example, in the case where the "divalent organic group" has a monocyclic hydrocarbon ring group or a crosslinked cyclic hydrocarbon ring group in its structure, at the terminal of its group, it is a double with the repeating unit (1) ( The spacer between the trifluoromethyl)-hydroxymethyl group is preferably a structure in which a linear alkyl group having 1 to 4 carbon atoms is bonded. In the "divalent substituent" described above, a divalent hydrocarbon group having a 2,5-extension borneol group, a 1,2-extended ethyl group or a stretching propyl group is preferred. In the general formula (2), the alicyclic hydrocarbon group having 4 to 20 carbon atoms of R3 can be enumerated, for example, norbornane, tricyclodecane, tetracyclododecane, adamantane, and cyclobutane, An alicyclic hydrocarbon group of a cycloalkane such as cyclopentane, cyclohexane, cycloheptane or cyclooctane; a hydrogen atom of such an alicyclic hydrocarbon group, for example, a methyl group, an ethyl group, or a n-propyl group One of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms, such as isopropyl, n-butyl, 2-methylpropyl', 1-methylpropyl or t-butyl. The base or the like substituted by the above or more. Among the alicyclic hydrocarbon groups, an alicyclic hydrocarbon group derived from ortho-norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane or cyclohexane, and such an alicyclic hydrocarbon group A hydrogen atom or the like substituted by the aforementioned alkyl group is preferred. -24- 200804989 (21) The fat-soluble resin used to form the protective film may not contain all of the repeating units (1) or repeating units (2), and may contain only one type, and may contain two or more types. . Further, it may contain a repeating unit other than the repeating unit (丨) or the repeating unit (2). However, the total content ratio of the repeating unit (〗) and the repeating unit (2) is preferably from 50 to 100%, and more preferably from 60 to 100% by mole, based on the total repeating unit. 70 to 100% of the mole is especially good. When the total content of the repeating unit (1) and the repeating unit (2) is 5 0 φ mol% or less, the characteristics as a protective film may not be sufficiently exhibited. The molecular weight range of the fat-soluble resin forming the protective film is not particularly limited, and various molecular weight ranges can be produced as needed. The mass average molecular weight (sometimes referred to as "Mw") converted to polystyrene by gel permeation chromatography (GPC), usually 2,000 to 200,000, preferably 2,500 to 1,00,000, and 3,000 to 50,000. good. By forming such a range, there is an advantage that a protective film excellent in solubility in an organic solvent and having high water resistance and mechanical properties can be formed. On the other hand, if the Mw of the fat-soluble resin in the form of a protective film is less than 2,000, it is feared that a protective film having high water resistance and high mechanical properties cannot be formed. Further, when Mw is more than 200,000, the solubility in an organic solvent may be lowered. Further, the fat-soluble resin for forming the protective film is preferably as small as impurities such as halogen or metal, so that the coatability as a protective film and the uniform solubility to an organic solvent can be further improved. For the resin purification method, for example, a chemical purification method such as water washing or solution extraction, and a purification method in which the chemical purification method is combined with a physical purification method such as ultrafiltration or centrifugation. The fat-soluble resin used to form the protective film may be used singly or in combination of two or more kinds of -25-200804989 (22). The fat-soluble resin for forming a protective film is added to a suitable organic solvent, and the total solid concentration thereof is adjusted to about 0.1 to 20% by mass, and the solution is filtered to prepare a coating liquid with a filter paper having a pore diameter of about 3 Onm, and This coating liquid can be formed by coating on a photoresist film using a previously known coating method such as rotary coating, flow coating, roll coating, or the like. This protective film can be calcined in order to volatilize the solvent. The organic solvent used in the preparation of the above coating liquid can be appropriately selected in consideration of the solubility of the fat-soluble resin. However, it is preferred to use an alcohol, and it is more preferable to use a monohydric alcohol to use a carbon number of 1 to 10. Monohydric alcohols are particularly good. These organic solvents are excellent in solubility of the fat-soluble resin, and it is preferable that the interlayer of the photoresist film to be coated is difficult to be mixed, and the possibility of adversely affecting the lithographic performance is low. Examples of the "1 to 10 carbon atoms of the carbon number" include methanol, ethanol, 1-propanol, isopropanol, n-propanol, 1-butanol, 2-butanol, tert-butanol, and 1-pentyl. Alcohol, 2-pentanol, 3-pentanol, n-hexanol, cyclohexanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2-methyl-1-butanol, 3 -methyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3 -Methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, etc., having 1 to 6 carbon atoms ; 2,2-dimethyl-3-pentanol, 2,3-dimethyl-3-pentanol, 2,4-dimethyl-3-pentanol, 4,4-dimethyl-2- Pentanol, 3-ethyl-3-pentanol, 1-heptanol, 2-heptanol, 3-heptanol, 2-methyl-2-hexanol, 2-methyl-3-hexanol, 5- 7-membered ones having a carbon number of methyl-1-hexanol or 5-methyl-2-hexanol; 2-ethyl-1-hexanol, 4--26 - 200804989 (23) methyl- 3-heptanol, 6-methyl-2-heptanol, 1-octanol, 2-octanol, 3-octanol, 2-propyl-1-pentanol, 2,4,4-trimethyl- 1-pentanol and the like, 8 carbon atoms, 2,6-dimethyl-4-heptanol, 3- a carbon number of one of the alcohols of 2,2-dimethyl-1-pentanol, 1-nonanol, 2-nonanol, 3,5,5-trimethyl-1-hexanol; 1-nonanol, 2-nonanol, 4-nonanol, 3,7-dimethyl-1-octanol, • 3,7-dimethyl-3-octanol, etc. class. Among these alcohols, it is preferable to use 4-methyl-2-pentanol, butanol, hexanol or a mixed solvent thereof for the reason that it is difficult to coagulate at a low temperature and it is difficult to remain in the photoresist film. In the organic solvent for preparing the coating liquid, other solvents may be mixed for the purpose of adjusting the coating property to the photoresist film. In the case where the protective film is uniformly applied, the "other solvent" can be sufficiently dissolved to form a resin for a protective film, and a solvent which is difficult to dissolve the photoresist film can be appropriately selected. Examples of the "other solvent" include polyhydric alcohols such as ethylene glycol and propylene glycol; cyclic ethers such as tetrahydrofuran and dioxane; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, and ethyl Glycol diethyl ether, diethylene glycol monomethyl ether m, diethylene glycol monoethyl ether, dimethyl dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol single An alkyl ether of a polyhydric alcohol such as diethyl ether; an alkyl ether of an alcohol such as ethylene glycol ethyl ether acetate, diethylene glycol diethyl ether acetate, propylene glycol ethyl ether acetate or propylene glycol monomethyl ether acetate; acetate; toluene; An aromatic hydrocarbon such as xylene; a ketone such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone or diacetone alcohol; Ethyl acetate, butyl acetate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, hydroxyl Ethyl acetate, methyl 2-hydroxy-3-methylbutanoate-27- 200804989 (24), 3-methoxypropionic acid, ethyl 3-methoxypropionate, 3-ethoxypropionic acid An ester such as methyl 3-ethoxypropionate; water or the like, wherein a cyclic ether, an alkyl ether of a polyhydric alcohol, an alkyl ether acetate of a polyhydric alcohol, a ketone, an ester, or water is used. It is better. The organic solvent may be used singly or in combination of two or more kinds, and may contain water as long as the uniformity of the solvent can be maintained. Since it is difficult to coagulate at a low temperature and exhibits an effect of being hard to remain on the photoresist film, the carbon number of the organic solvent is preferably 10 to 100% by mass based on the total solvent, and is 20 to 100%. The mass % is better. In the above coating liquid, a surfactant may be blended for the purpose of improving coatability, defoaming property, leveling property, and the like. As the surfactant, the following BM-1 000, BM-1 100 (above, BM Chem), Mega fac F142D, F172, F173, and F183 (above, Dainippon Ink Chemical Industry Co., Ltd.) can be used. System), Floride FC-135, with FC-170C, with FC-430, with FC-431 (above, Sumitomo 3M Company _ system), Sufuron S-112, same S-113, same S-131, same S= 141. Fluorine-based surfactants such as S-145 (above, manufactured by Asahi Glass Co., Ltd.), SH-28PA, homo-190, homo-193, SZ-6032, and SF-8428 (above, manufactured by Dowconing Silicone Co., Ltd.) . The blending amount of the surfactants is preferably 5 parts by mass or less based on 100 parts by mass of the fat-soluble resin. The thickness of the protective film is preferably as close as possible to an odd multiple of λ / 4 m (however, λ: wavelength of radiation, m: refractive index of the protective film). The effect of suppressing reflection on the upper interface of the photoresist film is increased. -28- 200804989 (25) [3] Immersion exposure: The method of the present invention is to irradiate the photoresist film with radiation in a state in which a liquid (liquid immersion liquid) having a higher refractive index than air is present. The step of immersion exposure of photoresist 0 exposure. If the liquid immersion liquid is a liquid having a higher refractive index than air, it is usually • water is used, and pure water is preferably used. In the state in which the liquid immersion liquid is present (that is, in the state of being filled with the liquid immersion liquid between the lens of the exposure device and the photoresist film), the radiation is irradiated through the reticle having the specified pattern to make the photoresist film exposure. The radiation that can be used for the immersion exposure is appropriately selected depending on the type of the photoresist film and the protective film to be used, and for example, visible light rays, ultraviolet rays such as g-rays, i-rays, and ultraviolet rays such as excimer lasers can be used. ; X-rays such as synchrotron radiation; various kinds of radiation such as charged particle rays such as electron beams. Among them, ArF laser laser (wavelength 193ixm) or KrF laser laser (wavelength 248nm) is preferably used. Further, the exposure conditions such as the amount of the radiation line are appropriately set depending on the composition of the radiation-sensitive resin composition, the type of the additive, and the like. [4] Peeling protective film: After the photoresist film is exposed, the protective film is peeled off from the surface of the above-mentioned photoresist film. In the method of the present invention, it is characterized in that the protective film is peeled off after heat treatment after exposure and development. Although it is also considered to peel off the protective film during alkali development of the photoresist film, the peeling of the protective film by heat treatment after exposure and development can effectively prevent water marks caused by the liquid immersion liquid impregnated with the protective film - 29 - 200804989 (26) Defects in defects and patterns. The method of peeling is not particularly limited, but a method of not impairing the performance of the photoresist pattern of the photoresist film is preferred. For example, a method of forming a protective film by a fat-soluble resin as described above and performing peeling of the protective film using an organic solvent is preferable. • The organic solvent used for the release of the protective film varies depending on the composition of the protective film, but a monohydric alcohol is preferred, and one of the alcohols having a carbon number of 10 or less is particularly preferred. Such an organic solvent is excellent in solubility of a protective film, and it is preferable that the interdiction of the barrier film is mixed with the photoresist film to cause a decrease in lithographic performance. Among the monohydric alcohols, it is difficult to coagulate at a low temperature, and even if it is used for peeling off the protective film, it is difficult to remain in the photoresist film, and 4-methyl-2-pentanol, butanol, hexanol or a mixed solvent thereof is used. good. Further, the monohydric alcohol may be used in combination with other organic solvents, but the monohydric alcohol is preferably contained in an amount of 10 to 100% by mass, and preferably 20 to 100% by mass, based on the total mass of the mixed solvent. The organic solvent used in the release of the protective film may also contain an acid. In this case, the acid _ is preferably a compound having a dissociation constant (pKa) of 5 or less. A compound having a dissociation constant (pKa) of more than 5 may cause discomfort such as head expansion in the cross-sectional shape of the photoresist pattern after development. A compound having a dissociation constant (pKa) of 5 or less is preferably an organic acid, and a sulfonic acid having a sulfo group (-so2oh) or a carboxylic acid having a carboxyl group in the molecule is more preferable, and a sulfonic acid is particularly preferred. Sulfonic acids are suitable for use because of their small dissociation constant (PKa) and high acidity. The sulfonic acid may, for example, be methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, isopropanesulfonic acid, butanesulfonic acid, isobutanesulfonic acid, 1,1-dimethylethanesulfonic acid, pentyl-30-200804989 (27) alkanesulfonic acid '1-methylbutanesulfonic acid, 2-methylbutanesulfonic acid, 3-methylbutanesulfonic acid, neopentanesulfonic acid, hexanesulfonic acid, oxalic acid-sulfonate- Alkyl sulfonic acids such as acid, octane sulfonic acid, decane sulfonic acid, decane sulfonic acid, etc.; benzenesulfonic acid, 2-toluenesulfonic acid, 3-toluenesulfonic acid, 4-toluenesulfonic acid, 4-ethyl Benzenesulfonic acid, 4-propylbenzenesulfonic acid, 4·butylbenzenesulfonic acid, 4-(t-butyl)benzenesulfonic acid, 2,5-dimethylbenzenesulfonic acid, 2-mercaptosulfonic acid, 2,4-Dinitrobenzenesulfonic acid, 4-chlorobenzenesulfonic acid, 4-bromobenzenesulfonic acid, 4-fluorobenzenesulfonic acid, 2,3,4,5,6-pentafluorobenzenesulfonic acid , 0 4 - arylsulfonic acid such as benzenesulfonic acid, 4-sulfobenzoic acid or 4-sulfoaniline, aralkylsulfonic acid such as benzylsulfonic acid or phenethylsulfonic acid, camphorsulfonic acid Such as ring sulfonic acids and the like. The organic solvent used for the release of the protective film may contain an acid alone or may contain two or more kinds of acids. [5] Post-exposure heat treatment: In the method of the present invention, after the protective film is peeled off from the surface of the photoresist film, post-exposure heat treatment (Post Exposure Bake, hereinafter "may be described as "PEB"). By performing PEB, it is preferable to improve the resolution, pattern shape, development property, and the like of the photoresist. The heating condition of PEB. varies depending on the composition of the radiation-sensitive resin composition, the type of the additive, and the like, but is preferably 30 to 200 ° C, and more preferably 50 to 150 ° C. [6] Development: In the method of the present invention, after the post-exposure heat treatment, development is carried out to obtain a photoresist pattern-forming body. For example, when a photoresist film obtained from a composition containing an acid-dissociable group-modified alkali-soluble resin and a radiation-sensitive linear acid-sensitive resin of the radioactive acid generator, 200804989 (28), it can be imaged by an alkali developing solution. The photoresist pattern forms a body. As the alkali developing solution, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, sodium metasilicate, ammonia, ethylamine, n-propylamine, monoethylamine, di-n-propylamine can be used. , triethylamine, methyldiethylamine, monomethylethanol-amine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrolidine, choline, 1,8-dioxin Bicyclo[5·4·0]-7-undecene, 1,5-diindole

It is preferred that at least one of the basic compounds such as bicyclo [4.3.0]-5-decane is dissolved in an aqueous solution of W alkali. Among them, an aqueous solution of a tetraalkylammonium hydroxide is suitably used. The concentration of the alkaline aqueous solution is preferably 1% by mass or less, more preferably 1 to 1% by mass, and particularly preferably 2 to 5% by mass. When the concentration of the alkaline aqueous solution is at most 10% by mass, it is preferable to prevent the non-exposed portion from being dissolved in the alkali developing solution. In the alkali imaging solution, a surfactant may be appropriately used. The addition of the φ surfactant improves the wettability of the developing solution to the photoresist. > Development is carried out, for example, by immersing the exposed photoresist film in an alkali developing solution. Usually, after development, the alkali developing solution is washed with water and dried to obtain a photoresist pattern shaped body. [Examples] Hereinafter, a method for producing a photoresist pattern type of the present invention will be described more specifically by way of examples. However, these embodiments are merely illustrative of one embodiment of the present invention - 32-200804989 (29). That is, the invention should not be construed as being limited to the embodiment. [Synthesis Example 1] First, a soluble resin for forming an ion-based modified base for forming a photoresist film was synthesized by the following method. In advance, the following compound (M-1) 5 3.93 g (50), compound (M-2) 3 5.3 8 g (40 mol%), and compound) 10.69 g (10 mol%) were dissolved in 200 g of 2-butanone, a monomer solution of 2,2'-azobis(dimethyl 2-methylpropionate) (polymerization initiator) 5. On the other hand, 100 g of 2-butanone was placed in a 5-inch flask of 5 ml, and nitrogen was purged for 3 minutes. After purging the nitrogen gas, the internal stirring of the three-necked flask was heated at 8 (rc, and the above-mentioned monomer solution prepared in advance was dropped for 3 hours using a bucket. The lower one was regarded as the polymerization start time, and the polymerization reaction was carried out for 6 hours. The actual acid hydrolysis of the mole % 丨 (M-3 added + 58 grams of 'put one side will drop the leak start to drop [Chemistry 6]

After the completion of the nozzle reaction, the polymerization solution was cooled to -33 - 30 by water cooling, C was taken up to 200804989 (30), and the cooled polymerization solution was poured into 2000 g of the precipitated white powder. Methanol was added to the filtered white powder, and the operation of washing in a slurry state was repeated twice, and then a white powder was again discharged and dried at 50 ° C for 17 hours to obtain a white polymer (74 g, produced). The rate is 7 4 %). The polymer was Mw, Mw/Mn=1.70, and 13C-NMR analysis. The repeating unit yield of the compound (, compound (M-2), compound (M-3) was 53.0: 37.2: 9.8 (Mole%) copolymer. This is a polyacrylic polymer (A-1). The content of the low molecular weight component of the polymer in the polymer is 0 with respect to the polymer 1 〇〇. 0. 3 mass%. [Synthesis Example 2] Next, a resin for forming a protective film was synthesized according to the following method: 0 In advance, chloroacrylic acid (trifluoro-2,trifluorohydroxy-4-pentyl) ester was prepared. 93.91 g (85 mol%) was dissolved in 1 g of the monomer solution (1), and 6.09 g (15) of vinylsulfonic acid was dissolved in 50 g of the monomer solution (2) of isopropanol. In a 500 ml three-necked flask equipped with a thermometer and a dropping funnel, nitrogen bis-(2-methylpropionate polymerization initiator) was charged with 6.91 g of alcohol 2 〇g' and purged with nitrogen for 3 Torr. After purging the nitrogen gas, the inner side is stirred with a magnetic stirrer, heated at 80 ° C, and the funnel is lowered, and the previously prepared monomer solution (1 ) is dripped for 20 minutes. The content of alcohol, 400 gram, 6900 ^ :M-1 of the filter powder is regarded as the % by mass of each of the fat-soluble methyl-2-cutinol, which is 2, 2, - even and different. C. Use the flask to drip. Drip-34 - 200804989 (31) After the end, the reaction was continued for another 20 minutes, and the previously prepared monomer solution (2) was dropped for 20 minutes, and the reaction was continued for another hour. After cooling to 30 ° C or less, copolymerization was carried out. liquid. The above copolymerization liquid was resuspended in 48,000 g of water, stirred for 30 minutes, and then filtered. The obtained white powder was dissolved in 1 ml of methanol, and 1 000 ml of n-heptane was added, and the liquid separation operation was repeated four times to carry out washing of the lower layer (methanol layer). After the solvent of the lower layer thus obtained was replaced with 4-methyl-2-pentanol, water was added thereto, and the mixture was separated and washed, and the solvent was replaced with 4-methyl-2-pentanol. The solid content concentration of the sample after solvent replacement was 0.3 g of the resin solution placed on the aluminum dish, and the mass of the residue was heated on a hot plate heated to 140 ° C for 2 hours, and was used for subsequent formation. Modulation and yield calculation of the coating liquid for protective film. Mw, Mw/Mn (degree of dispersion of molecular weight) and yield (% by mass) of the obtained copolymer were 583 0, 1.7, and 72%, respectively. [Preparation of Sensitive Radiation Resin Composition]: To a mass fraction of an alkali-soluble resin modified with an acid dissociable group of Synthesis Example 1, a triphenylsulfonium hexafluoride-positive-type as a sensitive radiogenic acid generator was added. 6 parts by mass of butane sulfonate, 6 parts by mass of 1 (4-n-butoxynaphthyl)tetrahydrothiophenyl trifluoromethanesulfonate, oxime-butoxycarbonylpyrrolidine as acid diffusion inhibitor 0.65 parts by mass, 30 parts by mass of γ-butyrolactone as a sub-solvent, and 2,300 parts by mass of propylene glycol monomethyl ether acetate as a main solvent were added, and the respective components were mixed to prepare a homogeneous solution. Thereafter, it is filtered by a membrane filter having a pore size of 〇·2 μm to prepare a coating liquid (total solid concentration concentration of about 6 mass%) of a radiation-sensitive resin red pigment-35-200804989 (32). [Preparation of coating liquid for forming a protective film]: To 100 parts by mass of the fat-soluble resin synthesized in Synthesis Example 2, 4-methyl-2-pentanol was added thereto, and the total solid content concentration was adjusted to 3.5. The mass % * was filtered through a filter paper having a pore size of 〇 2 μm to prepare a coating liquid for a protective film [Preparation of a protective film peeling liquid]: Preparation of 4-methyl-2-pentanol containing 0.075 mass% camphorsulfonic acid, The membrane was filtered through a filter paper having a pore size of 0.2 μm to prepare a protective film stripper. [Evaluation method]: The coating liquid for protective film and the protective film peeling liquid were formed using the photosensitive radiation resin composition prepared as described above, and the following evaluation was carried out. (1) Forced water mark test: Using Coater/Developer (1) (trade name: CLEAN TRACK ACT8, manufactured by Tokyo Electron Co., Ltd.), anti-reflection forming agent on 8 吋矽 wafer (trade name: ARC29A, Blower Science) The company was spin-coated, and PB was performed at 205 ° C for 60 seconds to form an antireflection film having a film thickness of 77 nm. Next, on the surface of the antireflection film, the coating liquid composed of the above-mentioned radiation sensitive resin composition was spin-coated, and PB was carried out at 115 ° C for 60 seconds, and the shape was -36-200804989 (33 ) A photoresist film with a film thickness of 15 Onm. Further, on the surface of the resist film, the coating liquid for forming a protective film was spin-coated, and PB was formed at 90 ° C for 60 seconds to form a protective film having a film thickness of 90 nm. Next, the photoresist film forming the protective film was exposed to an optical condition of NA: 0.78, Sigma: 0·85, 2/3 Ann by an ArF projection exposure apparatus (trade name: S306C, manufactured by Nikkon Co., Ltd.). Test wafer. Thereafter, 0.3 μl of water droplets were pipetted using a pipette and marked on the wafer surface and allowed to dry for 1 minute. In the first embodiment, the protective film was peeled off in the protective film peeling solution, and the PEB was subjected to the hot plate of the Coater/Developer (1) at 115 ° C for 60 seconds, and the same Coater was used. The LD nozzle of /Developer (1) was subjected to paddle image development for 60 seconds, then washed with ultrapure water, and shaken again at a revolution of 4000 rpm for 15 seconds, and then spin-dried. On the other hand, in the comparative example, after the protective film was peeled off and PEB was carried out under the same conditions as in Example 1, the protective film was peeled off during the development of the photoresist film. The pattern of the photoresist formed by the treatment was visually observed, and it was judged as "good" by the fact that the droplet mark (water mark) was not left at the position of the pipette mark, and the residual condition was judged as "poor". The results are shown in Table 1. Table 1 Forced water mark test sensitivity pattern defective defect pattern shape Example 1 Good 19 mJ/cm 2 Good good Comparative example 1 Bad 19 mJ/cm 2 Poor good -37- 200804989 (34) (2) Sensitivity: Using Coiter/Oevei 〇p_er(2) (trade name: CLEAN TRACK ACT12, manufactured by Tokyo Electron Co., Ltd.), and a spin-resistant forming agent (trade name: ARC29A, manufactured by Blower ~ Science Co., Ltd.) was spin-coated on a 12-inch wafer. PB was carried out under the conditions of 205 ° C for 60 seconds to form an antireflection film having a film thickness of 77 nm. This material was used as a substrate. ^ Next, the coating liquid composed of the above-mentioned radiation-sensitive resin composition is spin-coated on the surface of the antireflection film of the substrate, and PB is performed at η 5 ° C for 60 seconds to form a film thickness of 150 nm. Photoresist film. Further, on the surface of the photoresist film, the coating liquid for forming a protective film was spin-coated, and PB was formed at 90 ° C for 60 seconds to form a protective film having a film thickness of 90 nm. Next, a photoresist film forming a protective film is used as an ArF laser laser exposure apparatus (trade name: TWIN SCAN XT125〇i, manufactured by ASML, certified conditions; ΝΑΟ·85, Sigma 0.93/0.69), φ through the mask The pattern makes it exposed. Thereafter, in Example 1, the protective film was peeled off in advance by the protective film peeling liquid, and enthalpy was carried out at a temperature of 1 15 ° C for 60 seconds, and tetramethylammonium hydroxide was added in an amount of 2.38 mass%. The aqueous solution was developed at 23 ° C for 30 ^ seconds, washed with water and dried to form a positive photoresist pattern. In Comparative Example 1, after the protective film was peeled off and PEB was carried out under the same conditions as in Example 1, the protective film was peeled off during alkali development of the photoresist film. For the photoresist pattern formed by such processing, the exposure amount formed by the line/space pattern (1 L 1 S ) having a line width of 65 nm with a line width of 1:1 is regarded as an optimum exposure amount - 38 - 200804989 (35) And consider this optimum exposure as sensitivity. Further, a scanning electron microscope (trade name: S-93 80, manufactured by Nippon Technology Co., Ltd.) was measured here. The results are shown in Table i. ' (3) Pattern defect inspection: • Coater/Dev eloper (2) (trade name: TRACK ACT12, manufactured by Tokyo Electron Co., Ltd.), anti-reflective film forming agent at 12 吋$ (trade name: ARC 29A) , manufactured by Science Co., Ltd., spin-coated, and PB was carried out at 205 ° C, 60 to form an antireflection film having a film thickness of 77 nm. Use this as a substrate. A pattern of a radiation sensitive resin composition name: ArF AR20 14J, manufactured by JSR Co., Ltd. was applied to the surface of the substrate. The radiation-linear resin composition was spin-coated on the surface of the substrate at 1 15 ° C for 60 seconds to form a film having a film thickness of 150 nm φ. On the surface of the photoresist film, the above-mentioned coating liquid for engraving a protective film was applied by spin coating, and PB was formed at a temperature of 90 ° C for 60 seconds to form a protective film of 32 nm. The photoresist film forming the protective film was passed through a reticle pattern light using an ArF excimer laser (trade name: TWIN SCAN XT 1 250i, manufactured by ASML); NA 0.85, Sigma 0.93/0.69.

Thereafter, in the first embodiment, the protective film stripping solution is kept away, and a Coater/Developer (2) hot plate is used, and a high CLEAN 矽 wafer is used for a second time at 115 ° C. The aforementioned sensitivity, and the photoresist is rotated into a film thickness exposure package, which proves that the film is peeled off, and the condition of 60 seconds - 39 - 200804989 (36) clock is carried out, and the Coater/Developer (2) mouth is used. The paddle was imaged for 30 seconds, washed with ultrapure water, and shaken at 3,000 rpm for 15 seconds, and then spin-dried. Regarding Comparative Example 1, the protective film was not peeled off and PEB was subjected to the conditions of the examples. When the alkali film of the photoresist film is developed, the protective film is formed into the photoresist pattern thus formed, and the general name: the missing name (trade name · KLA235 1, manufactured by KLA-Tencor Co., Ltd.) is used for defect inspection, and scanning is performed. An electron microscope (trade name: S · Liji Co., Ltd.) observes the detected defects, and the presence of a defect (specifically, a thin or thick defect) is considered as a defective defect. "Poor", not detected is good. The results are shown in Table 1. (4) Shape: A section of the 65 nm line/space pattern was observed by a scanning electron microscope (trade name: S-4800, manufactured by E φ Technology Co., Ltd.) and the line in the middle of the photoresist pattern was measured as shown in FIG. The line width La of the upper portion of the width is 0.65 ^ ( La-Lb ) / Lb ^1.1 and the price is "good", and the evaluation is "bad". The result [evaluation result]: As illustrated by the data in Table 1, The LD tube of the resist pattern of the first embodiment in which the protective film was subjected to post-exposure heat treatment and development by the photoresist film was peeled off in the same manner as the number of revolutions 1. The inspection was performed on the wafer of 93 60, and the daily pattern was not. The test is regarded as "good 3 vertical shape, Lb, and the range of the film is shown in Table 1. After peeling, type, Yu Min-40-200804989 (37) In any test of the sensitivity and shape, On the other hand, after the post-exposure heat treatment, the shape of the resist pattern of Comparative Example 1 which was peeled off from the surface of the photoresist film was not good, but the water mark occurred. [Industrial Applicability] The method of forming the photoresist pattern of the present invention, Most of the water droplets remaining on the surface of the membrane are removed from the PEB, so that the occurrence of water marks caused by the water droplets can be effectively suppressed. Therefore, in the field of microfabrication, the development of miniaturization, high definition, and high integration has continued. It can be suitably used in the manufacture of circuit components. Good results. In addition, the film type will be protected before development, and the defects and the figure will be removed when the protective film is peeled off due to the lack of sensitivity and pattern. Type of defective 'special, in the set of semiconductor devices, etc. -41

Claims (1)

200804989 (1) X. Application for Patent Model 1. A method for forming a photoresist pattern, which is provided with a liquid (liquid immersion liquid) having a higher refractive index than air by means of an intermediary. a method for forming a *resist pattern of a liquid immersion exposure step for exposing the photoresist film, wherein the photoresist film is formed on a surface of the substrate, and the liquid immersion film is formed on the surface of the photoresist film The protective film of the liquid is irradiated to the photoresist film in a state in which the liquid immersion liquid is interposed, and the photoresist film can be exposed, and the protective film is peeled off from the surface of the photoresist film, and then exposed. Heat treatment and development to obtain a photoresist pattern. 2. The method for forming a photoresist pattern according to the first aspect of the invention, wherein the protective film is formed of a fat-soluble resin, and the protective film is peeled off using an organic solvent. Φ 3 · The method for forming a photoresist pattern according to claim 2, wherein the fat-soluble resin forming the protective film is composed of the following general formula (1) and the following general formula (2) Selecting at least one repeating unit of polymer from the group as a constituent, -42- 200804989 (2) • [However, in the general formula (1) or (2), R1 represents hydrogen, methyl or trifluoromethyl, R2 represents a divalent organic group, and R3 represents an aliphatic ring having 4 to 20 carbon atoms. a hydrocarbon group or a derivative thereof]. - 43 - 200804989 VII. Designated representative map: (1) The designated representative figure of this case is: None (2), the representative symbol of the representative figure is simple: no 8. If there is a chemical formula in this case, please reveal the chemical formula that best shows the characteristics of the invention: none -4-