JP2017020992A - Analytical method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an analytical method which is excellent in analysis accuracy of an organic film and can simply measure a trace component.SOLUTION: An analytical method includes: a step of mounting droplet on an organic film surface on a substrate; a step of moving the droplet onto the substrate so as to be brought into contact with the organic film; and a step of analyzing a component contained in the moved droplet, where droplet that can dissolve or disperse a component contained in the organic film is used as the droplet mounted in the mounting step. A main component of the organic film may be an acrylic resin, a novolac resin, a resol resin, a styrene resin, an acenaphthylene resin, an indene resin, an arylene resin, a triazine resin, a calixarene resin, a fullerene resin, a pyrene resin, an aromatic ring-containing compound having a molecular weight of 100 or more and 2,000 or less or a combination thereof. The main component of the organic film may be a silicone resin.SELECTED DRAWING: None

Description

  The present invention relates to an analysis method.

  Conventionally, in order to form a minute pattern on a substrate, a lithography process in which a resist film is formed on a substrate using a radiation sensitive resin composition, and the resist film is exposed and developed has been widely performed. In this lithography process, there is a further demand for pattern miniaturization in recent years. However, if the resist film contains a metal element as an impurity, the pattern formed by this metal element will have defects and the like, so there are few metal elements. Is preferred. Therefore, there is a need for a technique for accurately analyzing the composition of the resist film, particularly an analysis technique having a high accuracy for trace components.

  Examples of the method for analyzing the composition of the resist film include a method for measuring the radiation-sensitive resin composition itself used for forming the resist film, and a method for directly analyzing the resist film after film formation. In the method of measuring the conductive resin composition itself, there may be a difference between the measurement result and the composition in the actual resist film due to the influence of contamination or the like in the film forming process. In addition, when directly measuring the composition of the radiation-sensitive resin composition, it is difficult to measure if the solid content concentration of the radiation-sensitive resin composition is high. Therefore, the radiation-sensitive resin composition is generally diluted during measurement. There is a need to. As a result, there is a disadvantage that the concentration of trace components in the radiation-sensitive resin composition is lowered and the analysis accuracy is lowered. On the other hand, when measuring a high-concentration radiation-sensitive resin composition using a special instrument in order to improve analysis accuracy, a pretreatment of concentrating the radiation-sensitive resin composition with a concentrator is generally performed. In this case, the procedure becomes complicated and contamination is likely to occur during concentration. Therefore, many methods for directly analyzing the resist film after film formation have been performed.

  As an analysis method of such a resist film, for example, a method of analyzing the resist film by fluorescent X-rays can be mentioned (see Japanese Patent Laid-Open No. 7-198630). In this method, an impurity element is qualitatively and quantitatively analyzed by directly irradiating a resist film formed on a substrate with X-rays and measuring fluorescent X-rays emitted from the resist film.

  However, in the above method, since the thickness of the resist film to be measured is smaller than the arrival depth of the X-ray used for the measurement, there are few regions irradiated with X-rays in the resist film, and the amount of the substance to be analyzed is small. Therefore, there is a disadvantage that it is difficult to improve the analysis accuracy of impurities.

  In addition, in order to increase the region irradiated with X-rays in the resist film, it is conceivable to form a thick resist film and analyze the resist film. It is necessary to apply and dry the functional resin composition multiple times, and the inconvenience that the film formation procedure becomes complicated, and the time required for film formation increases the contamination during film formation. There is an inconvenience that the measurement result is likely to be different from the impurity content in the thin resist film used in the process.

JP-A-7-198630

  The present invention has been made based on the above circumstances, and an object thereof is to provide an analysis method that is excellent in the analysis accuracy of an organic film and that can easily measure a trace component.

  The invention made to solve the above problems includes a step of placing a droplet on the surface of the organic film on the substrate, a step of moving the droplet on the substrate so as to contact the organic film, and the post-movement The analysis method includes a step of analyzing a component contained in the droplet, and uses a droplet capable of dissolving or dispersing the component contained in the organic film as the droplet placed in the placing step.

Here, the “organic film” includes both a film containing an organic substance as a main component and a pattern formed from this film. “Main component” means the most abundant component (for example, 50% by mass or more) on a mass basis. “Components included in the organic film” (hereinafter also referred to as “organic film components”) includes both the component that forms the organic film, and the polymer main chain and compound bonds in this component that are cleaved. Is included.

  As described above, according to the analysis method of the present invention, trace elements can be easily measured with excellent organic film analysis accuracy. Therefore, the analysis method of the present invention can be suitably used for analyzing a resist film or the like used in a lithography process that requires higher accuracy.

It is typical sectional drawing which shows an example of the analyzer used for the analysis method of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The analysis method includes a step of placing a droplet on the surface of the organic film on the substrate (placement step), a step of moving the droplet on the substrate so as to contact the organic film (movement step), and the movement It mainly includes a step (analysis step) of analyzing components contained in the subsequent droplets. These steps are preferably performed in this order.

  In the analysis method, since the droplet can dissolve or disperse the organic film component, the droplet dissolves or disperses the organic film in the placing step, and the droplet dissolves or disperses the organic film in the moving step. Move while. As a result, with this movement, the content ratio of the organic film component in the droplet increases, and a droplet composed of a high concentration organic film component-containing liquid is generated. Thereafter, by analyzing the droplets in the analysis step, the amount of the organic film component to be analyzed is increased as compared with the case where the resist film is directly irradiated with X-rays for analysis. In this analysis method, since all steps from concentration of organic membrane components to analysis can be performed in a single analyzer, complicated pretreatment is not required and contamination is unlikely to occur. As a result, the analysis method has excellent analysis accuracy and can easily measure trace elements.

  The analysis method may further include a step (removal step) of removing at least a part of the liquid component in the droplet between the moving step and the analysis step. By this removal step, the content ratio of the organic film component in the droplets is further increased, so that the analysis accuracy can be further improved.

  Further, the organic film may be dissolved or dispersed in the droplets in the whole thickness direction in the region where the droplets on the surface of the organic film are placed in the placing step or the region where the droplets move in the moving step. In this case, the liquid droplet moves on the surface of the substrate in the moving process after contacting the substrate in the placing process. Further, only a part of the organic film in the thickness direction in the region may be dissolved or dispersed in the droplet. In this case, the droplet contacts only the organic film and moves on the organic film without contacting the substrate. Among these, it is preferable that the organic film is dissolved or dispersed in the droplets in all thickness directions. In general, since the contact angle of the droplet on the substrate surface is larger than the contact angle of the droplet on the organic film, the droplet comes into contact with the substrate surface, so that it becomes easy to move the droplet as a unit when the droplet moves.

<Installation process>
In the placing step, the droplet is placed on the surface of the organic film on the substrate. When a part of the organic film in contact with the droplet is dissolved or dispersed, the organic film component moves into the droplet.

[substrate]
The substrate has an organic film laminated on at least one surface. A known substrate can be used as this substrate, and examples thereof include a silicon wafer, silicon dioxide, and a wafer coated with aluminum. Among these, those that do not dissolve in droplets are preferable, and a silicon wafer is preferable from this viewpoint.

[Organic film]
The organic film is laminated on at least one surface of the substrate and is an analysis target in the analysis method. In addition, at least a part of the organic film is dissolved or dispersed in the droplets in the placing process and the moving process. The organic film may be laminated on all of the one surface of the substrate, or may be laminated only on a part thereof.

  As the main component of the organic film, acrylic resin, novolac resin, resol resin, styrene resin, acenaphthylene resin, indene resin, arylene resin, triazine resin, calixarene resin, fullerene resin, Pyrene-based resins, aromatic ring-containing compounds having a molecular weight of 100 to 2,000, and combinations thereof are preferred.

  Here, the “acrylic resin” means a polymer or copolymer having a structure of —CH—C (CO) — as a structural unit. The “fullerene resin” means a polymer or copolymer having a fullerene structure in the main chain or side chain. The “pyrene-based resin” means a polymer or copolymer having a pyrene structure in the main chain or side chain. “Molecular weight of an aromatic ring-containing compound” means the molecular weight when the aromatic ring-containing compound is a single compound, and means the weight average molecular weight when the aromatic ring-containing compound is a polymer or copolymer. .

  Examples of the acrylic resin include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl ( (Meth) acrylate, methylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, lauryl (meth) acrylate, isobornyl ( (Meth) acrylate, stearyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 1-ethylcyclopentan-1-yl (meth) acrylate, 2-methylada Structural units derived from ntan-2-yl (meth) acrylate, norbornanelactone-2-yl (meth) acrylate, γ-butyrolactone-yl (meth) acrylate, 3-hydroxyadamantan-1-yl (meth) acrylate, etc. Examples thereof include a polymer or copolymer.

  Examples of the novolak resin include phenols such as phenol, cresol, xylenol, resorcinol, bisphenol A, pt-butylphenol, and p-octylphenol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 2, Examples thereof include copolymers obtained by reacting naphthols such as 7-dihydroxynaphthalene or a phenolic compound that is a combination thereof with aldehydes, divinyl compounds, and the like with an acidic catalyst or the like.

  Examples of the aldehydes include aldehydes such as formaldehyde and aldehyde sources such as paraformaldehyde and trioxane.

  Examples of the divinyl compounds include divinylbenzene, dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, 5-vinylnoborn-2-ene, α-pinene, β-pinene, limonene, and 5-vinylnorbornadiene.

  Examples of the resol-based resin include a copolymer obtained by reacting the phenolic compound and the aldehyde with an alkaline catalyst.

  Examples of the styrenic resin include polymers or copolymers containing structural units derived from styrene, tert-butoxystyrene, hydroxystyrene, and the like.

  Examples of the acenaphthylene-based resin include polymers or copolymers containing structural units derived from acenaphthylene, those obtained by substituting some or all of the hydrogen atoms of acenaphthylene with substituents, and the like.

  Examples of the substituent include a halogen atom, a hydroxy group, a carboxy group, a nitro group, and a cyano group.

  Examples of the indene-based resin include polymers and copolymers containing structural units derived from indene and those in which some or all of the hydrogen atoms of indene are substituted with substituents. As this substituent, the same thing as the said acenaphthylene-type resin is mentioned.

  Examples of the arylene-based resin include polyarylene ether, polyarylene sulfide, polyarylene ether sulfone, and polyarylene ether ketone.

  Examples of the triazine resin include those obtained by condensing methylolated guanamine obtained by addition of guanamine or a guanamine derivative and formaldehyde.

  The lower limit of the molecular weight of the aromatic ring-containing compound is 100, preferably 150, and more preferably 200. On the other hand, the upper limit of the molecular weight is 2,000, preferably 1,800, more preferably 1,500.

  As the main component of the organic film, a silicone resin is also preferable. This silicone resin is a resin containing a silicon atom in the main chain. Examples of the silicone resin include methyl silicone resin, methyl phenyl silicone resin, epoxy modified silicone resin, epoxy / polyether modified silicone resin, carbinol modified silicone resin, methacryl modified silicone resin, phenol modified silicone resin, methyl styryl modified silicone. Resins, acrylic-modified silicone resins, methyl hydrogen silicone resins and the like can be mentioned.

  Furthermore, the organic film may contain an optional component other than the resin. This optional component can be appropriately selected according to the type of the organic film, and examples thereof include an acid generator and an acid diffusion controller in the resist film.

  As the organic film, a resist film, a resist lower layer film, a resist middle layer film, and a resist upper layer film are preferable. These films are those commonly used in lithography processes.

  Examples of the resist film include a film that is used in a lithography process and has a property that the solubility in a developing solution is changed by exposure and can form a pattern, and a reverse pattern film that is embedded between resist patterns. It is done.

  The resist underlayer film is a film directly laminated on one surface of the substrate. The resist film is formed on the surface of the resist underlayer film opposite to the substrate. Examples of such a resist underlayer film include an antireflection film and an organic underlayer film that functions as a mask during etching of a substrate in a multilayer resist process.

  The resist intermediate layer film is a film laminated between the resist film and the resist underlayer film in a multilayer resist process, and examples thereof include a so-called SOG (Spin on glass) film.

  The resist upper layer film is a film laminated on the side of the resist film opposite to the substrate, and examples thereof include a water-repellent film used for immersion exposure.

  The average thickness of the organic film can be appropriately changed according to the type of the organic film, but the lower limit thereof is preferably 20 nm, and more preferably 50 nm. On the other hand, the upper limit of the average thickness is preferably 1,000 nm, and more preferably 500 nm. If the average thickness is smaller than the lower limit, the absolute amount of the organic film component dissolved or dispersed in the droplets may be reduced, and it may be difficult to improve analysis accuracy. On the other hand, if the average thickness exceeds the upper limit, the organic film remains undissolved in the moving step, making it difficult to move the droplets, and it may be difficult to move the droplets as a whole.

  Examples of the method of laminating the organic film on the surface of the substrate include a method of applying and drying a mixture of an organic film component and a solvent on the substrate. Usually, when the resist film is formed, heating is performed after drying. However, in the analysis method, it is preferable not to perform this heating when forming the organic film. In particular, when the organic film is a resist film, a resist lower layer film, or a resist upper layer film containing an organic substance as a main component, the main component of the organic film may be cross-linked by heating, making it difficult to dissolve or disperse in droplets.

[Droplet]
The droplet contains a component capable of dissolving or dispersing the organic film component, and is placed on the surface of the organic film and moves on the substrate so as to be in contact with the organic film. Thereby, the organic film component is dissolved or dispersed in the droplet.

  The components of the droplets can be appropriately changed according to the composition of the organic film to be analyzed, and include organic solvents, organic acids or salts thereof, inorganic acids or salts thereof, organic bases or salts thereof, inorganic bases, hydrogen peroxide or It is preferable to include these combinations.

  Moreover, it is preferable that the said droplet is highly purified. That is, 10 ppb is the upper limit of the concentration of trace components other than the organic solvent, organic acid or salt thereof, inorganic acid or salt thereof, organic base or salt thereof, inorganic base, hydrogen peroxide, or a combination thereof in the droplet. Preferably, 1 ppb is more preferable. Since the droplets have high purity in this way, contamination derived from the droplets can be reduced, and the analysis accuracy of the organic film is further improved.

  Furthermore, when the droplets contain an organic acid or a salt thereof, an inorganic acid or a salt thereof, an organic base or a salt thereof, an inorganic base or a combination thereof, the liquid droplets may further contain a solvent or a dispersion medium that dissolves or disperses these components. preferable. Examples of the solvent or dispersion medium include organic solvents described later, inorganic solvents such as water, and the like.

  Examples of the organic solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.

Examples of the alcohol solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol , Sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec Heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methyl cyclohexanol, 3,3,5-trimethyl cyclohexanol, benzyl alcohol, mono-alcohol solvents such as diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 -Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, and polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
And aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, Linear ketone solvents such as di-iso-butyl ketone and trimethylnonanone;
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone;
2,4-pentanedione, acetonylacetone, acetophenone and the like can be mentioned.

Examples of the amide solvent include cyclic amide solvents such as N, N′-dimethylimidazolidinone and N-methylpyrrolidone;
Examples thereof include chain amide solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, and N-methylpropionamide.

Examples of the ester solvent include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, i-pentyl acetate, sec -Acetate solvents such as pentyl, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether Polyhydric alcohol partial ether acetate solvents such as acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate;
lactone solvents such as γ-butyrolactone and valerolactone;
Carbonate solvents such as diethyl carbonate, ethylene carbonate, propylene carbonate;
Glycol acetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl acetoacetate, ethyl acetoacetate, methyl lactate, ethyl lactate N-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of the hydrocarbon solvent include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, and cyclohexane. , Aliphatic hydrocarbon solvents such as methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene and n-amylnaphthalene Group hydrocarbon solvents and the like.

  Examples of the organic acid and salts thereof include acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oxalic acid, maleic acid, methylmalonic acid, adipic acid, and sebacin. Acid, gallic acid, butyric acid, meritic acid, arachidonic acid, mikimic acid, 2-ethylhexanoic acid, oleic acid, stearic acid, linoleic acid, linolenic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, p-toluenesulfonic acid Acid such as benzenesulfonic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, formic acid, malonic acid, sulfonic acid, phthalic acid, fumaric acid, citric acid, tartaric acid, pentafluoropropionic acid, and salts thereof. Can be mentioned.

  Examples of the inorganic acid and its salt include acids such as hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, and phosphoric acid, and salts thereof.

  Examples of the organic base and salts thereof include pyridine, pyrrole, piperazine, pyrrolidine, piperidine, picoline, trimethylamine, triethylamine, monoethanolamine, diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, diazabicycloocrane, Examples include bases such as diazabicyclononane, diazabicycloundecene, tetramethylammonium hydroxide, and salts thereof.

  Examples of the cation in the organic acid salt, inorganic acid salt, and organic base salt include alkali metal cations, alkaline earth metal cations, transition metal cations, and the like.

  Examples of the inorganic base include ammonia, sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide and the like.

  The main component of the organic film is acrylic resin, novolak resin, resol resin, styrene resin, acenaphthylene resin, indene resin, arylene resin, triazine resin, calixarene resin, fullerene resin, pyrene resin. In the case of a resin, an aromatic ring-containing compound having a molecular weight of 100 or more and 2,000 or less, and a combination thereof, the liquid droplets are an organic solvent, an organic acid or a salt thereof, an inorganic acid or a salt thereof, an organic base or a salt thereof, an inorganic base or These combinations are preferably included, more preferably organic solvents are included, ester solvents are further preferably included, lactone solvents are particularly preferably included, and γ-butyrolactone is further particularly preferably included.

  When the main component of the organic film is a silicone resin, the droplets preferably include an organic acid or a salt thereof, an inorganic acid or a salt thereof, or a combination thereof.

  Since the combination of the main component of the organic film and the component contained in the droplet is the above, the organic film can be efficiently dissolved or dispersed in the droplet in the moving step.

  The lower limit of the contact angle of the droplet on the substrate surface is preferably 35 °, more preferably 40 °. On the other hand, the upper limit of the contact angle is preferably 80 °, more preferably 75 °. If the contact angle is smaller than the lower limit, when the droplet is moved in the moving step described later, a part of the droplet remains on the substrate, making it difficult to move while maintaining the volume of the droplet. As a result, the absolute amount of the organic film component to be analyzed may be reduced, and the analysis accuracy may be difficult to improve. On the other hand, when the contact angle exceeds the upper limit, when the organic film is dissolved or dispersed in the whole thickness direction, the droplet is likely to move excessively on the surface of the substrate, and the movement speed of the droplet can be controlled. May be difficult. Here, the “contact angle” is a value measured according to JIS-R3257 (1999).

  When the substrate is a silicon wafer, a silicon dioxide film may be formed on the surface thereof. In this case, in order to make the contact angle of the droplet fall within the above range, it is preferable to perform a hydrophobic treatment on the substrate surface or to remove the silicon dioxide film by a vapor phase decomposition treatment.

  Examples of the hydrophobic treatment include a method of applying a surface treatment agent to the substrate surface, a method of bringing the surface treatment agent into contact with the substrate surface, and the like. Examples of the surface treatment agent include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl) -3. -Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltri Methoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-to Azadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl- 3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene ) -3-Aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, and hexamethyldisilazane. Of these, hexamethyldisilazane is preferred.

  The above-mentioned “vapor phase decomposition” means that, for example, a reactive gas such as hydrogen fluoride is introduced into the substrate surface to dissolve the silicon dioxide film on the substrate surface, and then hydrogen fluoride is applied to the substrate surface. A process of removing the silicon dioxide film from the substrate by a process such as dropping and collecting a recovery solution such as an acid solution.

  The lower limit of the boiling point of the liquid component in the droplet is preferably 30 ° C, more preferably 40 ° C, and further preferably 50 ° C. On the other hand, the upper limit of the boiling point is preferably 250 ° C, more preferably 220 ° C, and further preferably 200 ° C. When the boiling point is less than the lower limit, the liquid component is vaporized in the placing step or the moving step, and the volume of the droplet is reduced, so that a sufficient amount of the organic film may not be dissolved or dispersed. Conversely, if the boiling point exceeds the upper limit, it may be difficult to remove the liquid component in the droplets when the concentration step is performed.

  The volume of the droplet placed on the surface of the organic film can be adjusted as appropriate according to the component of the droplet, but it is preferably small enough to allow the droplets to move together in the moving process, and the entire organic film is dissolved. Or it is preferable that it is dispersible and is large to some extent. For example, when an organic film having an average thickness of 100 nm is laminated on a 12-inch wafer, the lower limit of the droplet volume is preferably 0.5 mL, more preferably 0.8 mL, further preferably 1.0 mL, and 2.0 mL. Particularly preferred. On the other hand, the upper limit of the volume is preferably 5.0 mL, and more preferably 4.0 mL.

  Further, only one or a plurality of droplets may be placed on the surface of the organic film. When mounting a plurality of droplets, it is preferable to finally collect the plurality of droplets at one place to form one droplet. Thereby, an organic film component can be efficiently recovered.

<Transfer process>
In the moving step, the droplet placed on the surface of the organic film is moved on the substrate so as to be in contact with the organic film. By moving the droplet while dissolving the organic film in contact with the droplet, the organic film component in the droplet gradually increases, and a droplet composed of a high concentration organic film component-containing liquid can be obtained.

  The droplet moving means in the moving step is not particularly limited. For example, a method of tilting the substrate and moving the droplet by its own weight, a method of moving the droplet by ejecting air or the like onto the droplet, a holder, etc. A method of moving a droplet by contacting the droplet and moving this holder, a method of moving a droplet relative to the substrate by fixing the droplet with a holder and moving or rotating the substrate, etc. Is mentioned. Among these, a method using a holder is preferable from the viewpoint of easy control of the moving speed of the droplets. In this case, the movement of the droplet by the movement of the holder and the movement of the droplet by the movement of the substrate may be performed together.

  Further, the movement path of the droplet on the substrate is not particularly limited, but it is preferable to move the entire surface of the organic film so as to dissolve the entire surface of the organic film. Thereby, the organic film | membrane component density | concentration in a droplet can be increased more.

  Furthermore, the path of movement of the droplets on the substrate is preferably a spiral shape in plan view, and more preferably a spiral shape from the outside to the inside. By adopting such a shape for the movement path of the liquid droplet, the final arrival point of the liquid droplet is the central portion of the substrate in plan view, and it is easy to align the irradiation position of the X-ray or the like irradiated in the analysis process. .

  The moving speed of the droplet can be adjusted as appropriate according to the component and volume of the droplet, but is preferably slow enough to allow the droplets to move together. If the moving speed is excessively high, the droplets may be divided and some of them may not move and remain on the substrate, which may make it difficult to move while maintaining the volume of the droplets. It may be difficult to dissolve or disperse in the droplet.

<Concentration process>
In the concentration step, at least a part of the liquid component in the droplet after the movement is removed. Thereby, the organic film component in the droplet is concentrated, and the analysis accuracy is further improved.

  As a method for concentrating droplets, heating or drying at room temperature can be considered, but heating is preferable from the viewpoint of shortening the processing time.

  The equipment used for concentration of the droplet is not particularly limited as long as it can remove the liquid component in the droplet and does not alter or volatilize the organic film component in the droplet, but it can be disposed in the analyzer. Some are preferred. In this way, by arranging the equipment used for concentration in the analyzer, the droplets can be concentrated without removing the substrate from the analyzer, and contamination can be further reduced. As such equipment, a halogen lamp is more preferable. Since the halogen lamp is simple to dispose in the analyzer and to operate at the time of heating, the droplet can be easily heated.

<Analysis process>
In the analysis step, the moved droplet or the concentrated droplet is analyzed.

  An analysis method in the analysis step is not particularly limited as long as it is used for ordinary quantitative analysis, but a fluorescent X-ray analysis method is preferable. By using fluorescent X-ray analysis as an analysis method, trace components can be analyzed efficiently.

  In addition, prior to the analysis of the moved droplet or the concentrated droplet, it is preferable to analyze a component of the droplet not containing the organic film component to obtain a blank value. Thus, by measuring the blank value corresponding to the component of only the droplet, and subtracting the blank value from the analysis value of the droplet after moving or the concentrated liquid droplet, the measured value due to impurities in the droplet The organic film component can be measured more accurately.

<Analyzer>
In the analysis method, a conventionally known analyzer can be used. Hereinafter, an example of the analyzer will be described with reference to FIG.

  The analyzer of FIG. 1 mainly includes a table 2 on which the substrate 1 is placed, and an irradiation unit and a sensor (not shown) arranged to face the surface of the table 2. Moreover, the organic film 4 as a surface to be measured is laminated on the substrate 1, and the substrate 1 with the organic film 4 is placed on the base 2 of the analyzer so that the organic film is on the sensor side. Thereafter, the droplet 3 containing an organic solvent or the like is placed on the surface of the organic film 4, the organic film 4 is dissolved or dispersed in the droplet 3, and then the organic film 4 component in the droplet 3 is analyzed.

  The analyzer preferably further includes a holder 5 that has a surface 5 a facing the surface of the organic film 4 and is movable in parallel to the surface of the organic film 4.

  Examples of the placement procedure of the droplet 3 when the analyzer includes the holder 5 include the following. First, the droplet 3 is placed on the surface of the organic film 4, and then the holder 5 is disposed so that the upper side of the droplet 3 opposite to the organic film 4 is in contact with the facing surface 5a.

  As another procedure for placing the droplet 3, the holder 5 is disposed so that the surface of the organic film 4 and the facing surface 5a are separated from each other, and then the surface of the organic film 4 and the facing surface 5a. For example, the droplet 3 is placed so as to fill the space between the two.

  Thus, the droplet 3 sandwiched between the surface of the organic film 4 and the holder 5a adheres to the opposing surface 5a of the holder 5 due to the surface tension, and the organic film 4 is removed as the holder 5 moves. The surface of the substrate 1 is moved while being dissolved or dispersed.

  As a material of the holder 5, it is necessary that the holder 5 is not dissolved or altered by the droplet 3. However, all the regions of the holder 5 do not have to have such a property, and at least the facing surface 5a only has to have such a property.

  Further, the contact angle of the droplet 3 on the facing surface 5a which is the surface in contact with the droplet 3 of the holder 5 is equal to the contact angle of the droplet 3 on the surface of the substrate 1, or the substrate 1 It is preferably smaller than the contact angle of the droplet 3 on the surface. Thus, when the contact angle on the facing surface 5a of the holder 5 is equal to or smaller than the contact angle on the substrate 1, the liquid from the space between the holder 5 and the surface of the substrate 1 when the holder 5 is moved. The droplet 3 becomes difficult to separate, and the droplet 3 can be moved more reliably.

  Examples of such an analyzer include an apparatus for measuring metal impurities adhering to the wafer surface described in JP-A-2005-109292.

  The holder 5 may be a nozzle. In this case, the droplet 3 is adsorbed to the holder 5 by bringing the tip of the nozzle into contact with the droplet 3 and setting the inside of the nozzle to a negative pressure.

  EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not interpreted limitedly based on description of this Example.

<Preparation of resin composition>
[Preparation of Resin Composition (X-1) (Radiation Sensitive Resin Composition)]
It shows below about the monomer and compound which were used for preparation of resin composition (X-1).

(Acid generator)
C-1: Triphenylsulfonium nonafluoro-n-butanesulfonate C-2: 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro-n-butanesulfonate

(Nitrogen-containing compounds)
D-1: Nt-butoxycarbonyl-4-hydroxypiperidine

(solvent)
E-1: Propylene glycol monomethyl ether acetate E-2: Gamma-butyrolactone

The monomer (M-1) 53.93 g (50 mol%), the monomer (M-2) 35.38 g (40 mol%), and the monomer (M-3) 10.69 g ( 10 mol%) was dissolved in 200 g of 2-butanone, and 5.58 g of dimethyl 2,2′-azobis (2-methylpropionate) was added to prepare a monomer solution. Next, 100 g of 2-butanone was charged into a 500 ml three-necked flask and purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the three-necked flask was heated to 80 ° C. while stirring, and the monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization start time was defined as the start of dropping, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization, the reaction solution was cooled to 30 ° C. or lower by water cooling. The reaction solution after cooling was poured into 2000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 400 g of methanol on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powder polymer (A-1) (74 g). , Yield 74%). Mw of the polymer (A-1) was 6900, and Mw / Mn was 1.70. As a result of ¹³ C-NMR analysis, the content (mol%) of each repeating unit derived from the monomers (M-1), (M-2), and (M-3) was 53.0: 37.2: 9.8. The content of the low molecular weight component derived from each monomer in the polymer (A-1) was 0.03%.

  100 parts by mass of the polymer (A-1), 1.5 parts by mass of (C-1) as an acid generator and 6.0 parts by mass of (B-2), (D-1) 0 as a nitrogen-containing compound Resin composition (X-1) was prepared by mixing 1.65 parts by mass and 1400 parts by mass of (E-1) as a solvent and 30 parts by mass of (E-2).

[Preparation of Resin Composition (X-2) (Composition for Forming Resist Underlayer Film)]
A 1000 ml three-necked flask equipped with a thermometer, a condenser and a magnetic stirrer was charged with 100 g of 2,7-dihydroxynaphthalene, 50.7 g of formaldehyde and 300 g of methyl isobutyl ketone under a nitrogen atmosphere and dissolved at room temperature. This solution was heated to 40 ° C., charged with 3.58 g of paratoluenesulfonic acid, further heated to 80 ° C. and aged for 11 hours. After aging, the solution was cooled to room temperature. The reaction solution after cooling was added to 5000 mL of methanol, and the precipitated reddish brown solid was filtered to recover the methanol solution. The recovered product was washed by pouring with a mixed solution of 300 g of methanol and 300 g of water, and dried under reduced pressure at 60 ° C. overnight to obtain 46.5 g of compound (A-2). Mw of the obtained compound (A-2) was 1500.

  10 parts by mass of the compound (A-2) was dissolved in 90 parts by mass of propylene glycol monomethyl ether acetate, and filtered through a membrane filter having a pore size of 0.1 μm to prepare a resin composition (X-2).

[Preparation of Resin Composition (X-3) (Composition for Forming Resist Middle Layer Film)]
An oxalic acid aqueous solution was prepared by heating and dissolving 1.28 g of oxalic acid in 12.85 g of water, and this oxalic acid aqueous solution was put into a dropping funnel. Thereafter, 25.05 g of tetramethoxysilane, 3.63 g of phenyltrimethoxysilane, and 57.19 g of propylene glycol monoethyl ether were charged into the flask, and a cooling tube and the dropping funnel were disposed in the flask. Next, the flask was heated to 60 ° C. in an oil bath, and an aqueous oxalic acid solution was slowly dropped from the dropping funnel and reacted at 60 ° C. for 4 hours. After completion of the reaction, the flask containing the reaction solution was allowed to cool and then placed in an evaporator to remove methanol produced by the reaction, thereby obtaining 97.3 g of a polysiloxane (A-3) solution. (A-3) The solid content in the solution was 18.0%. Moreover, the weight average molecular weight (Mw) of the polysiloxane in the (A-3) solution was 2000.

  9.40 parts by mass of the polysiloxane (A-3) solution, 21.75 parts by mass of propylene glycol monoethyl ether, and 68.75 parts by mass of propylene glycol monomethyl ether acetate are mixed and filtered through a filter having a pore size of 0.2 μm. Thus, a resin composition (X-3) was prepared.

[Preparation of Resin Composition (X-4) (Composition for Forming Resist Upper Layer Film)]
It shows below about the compound used for preparation of resin composition (X-4).

  100 g (100 mol%) of the compound (M-4) and 7.29 g (7 mol%) of azobisisobutyronitrile (AIBN) were dissolved in 100 g of 2-butanone to obtain a monomer solution. Next, 100 g of 2-butanone was charged into a 1000 mL three-necked flask and purged with nitrogen for 30 minutes. Thereafter, the three-necked flask was heated to 80 ° C., and the monomer solution was dropped over 3 hours using a dropping funnel while stirring. The polymerization start time was defined as the start of dropping, and polymerization was performed for 6 hours. After completion of the polymerization, the reaction solution was cooled to 30 ° C. or lower and concentrated under reduced pressure until the mass of the reaction solution became 150 g. After 150 g of methanol and 750 g of n-hexane were added to this concentrated liquid and separated, the lower layer liquid was recovered. 750 g of n-hexane was added to the recovered lower layer liquid, and separation and purification were again performed, and the purified lower layer liquid was recovered. The solvent was removed from the recovered lower layer solution, and 4-methyl-2-pentanol was added to obtain a polymer (A-4) -containing solution.

  100 parts by mass of the polymer (A-4) -containing solution and 7400 parts by mass of 4-methyl-2-pentanol (MIBC) are mixed and filtered through a filter having a pore size of 0.1 μm to obtain a resin composition (X-4 ) Was prepared. The solid content concentration of the resin composition (X-4) was about 1.5% by mass.

(Production Example 1)
Hydrophobizing the surface by bringing 12-inch silicon wafer into contact with vapor of hexamethyldisilazane, and then applying the resin composition (X-1) to the wafer surface with a spin coater (“Clean Track ACT12” from Tokyo Electron) The substrate with an organic film (B-1) having an average thickness of 200 nm was obtained by coating using

(Production Examples 2 to 4)
Except having used the resin composition of Table 1, it carried out similarly to the said manufacture example 1, and obtained the board | substrates (B-2)-(B-4) with an organic film. Table 1 shows the average thickness of the organic films in the substrates with organic films (B-2) to (B-4).

[Example 1]
The substrate with organic film (B-1) is placed on an X-ray fluorescence analyzer (“TXRF-V310” manufactured by Rigaku Corporation), and 1 mL of γ-butyrolactone (contact angle 40 ° on the silicon wafer surface) is resisted as a droplet It was mounted on the outer edge of the film surface. Using the holder of the fluorescent X-ray apparatus, the droplet was moved spirally from the outside to the inside on the resist film surface, and the entire resist film was dissolved in the droplet. Thereafter, the droplet was heated using a halogen lamp in the apparatus, and the liquid component in the droplet was removed to obtain a solid content. The solid content after removal was a circular film having a diameter of about 1 cm and an average thickness of 1 μm. This solid content was irradiated with X-rays and analyzed for its composition. The analysis results are shown in Table 2.

[Examples 2 to 4]
The composition of each organic film was analyzed in the same manner as in Example 1 except that the substrate with an organic film shown in Table 2 was used. The analysis results are shown in Table 2. In Table 2, “-” means that the corresponding element was not detected.

[Comparative Examples 1-4]
The organic film-coated substrates (B-1) to (B-4) are placed on the fluorescent X-ray analyzer, and the composition of each film is obtained by directly irradiating each film with X-rays without using droplets. Was analyzed. The analysis results are shown in Table 2.

  As shown in Table 2, in the measurement method of the example, sodium, magnesium, calcium, aluminum, iron, and nickel elements, which are trace components that are frequently contained in an organic film such as a resist film, are detected with high accuracy. I was able to. In particular, in Examples 1 to 3 in which the organic film was a resist film, a resist underlayer film, and a resist middle layer film (SOG film), the analysis accuracy of these trace components was superior.

  On the other hand, in Comparative Examples 1 to 4 in which the same organic film as in the example was analyzed without using droplets, the content ratio of the trace component in the organic film was smaller than the detection limit, and the content of the trace component was measured. I couldn't.

  As described above, according to the analysis method of the present invention, a trace component can be easily measured with excellent organic film analysis accuracy. Therefore, the analysis method of the present invention can be suitably used for analyzing a resist film or the like used in a lithography process that requires higher accuracy.

1 substrate 2 units 3 droplet 4 organic film 5 holder 5a opposite surface

Claims (8)

Placing droplets on the surface of the organic film on the substrate;
A step of moving the droplet on the substrate so as to be in contact with the organic film, and a step of analyzing a component contained in the droplet after the movement,
The analysis method using the droplet which can melt | dissolve or disperse | distribute the component contained in the said organic film as a droplet mounted in the said mounting process.   The main component of the organic film is acrylic resin, novolac resin, resol resin, styrene resin, acenaphthylene resin, indene resin, arylene resin, triazine resin, calixarene resin, fullerene resin, pyrene. The analysis method according to claim 1, which is a resin based resin, an aromatic ring-containing compound having a molecular weight of 100 or more and 2,000 or less, or a combination thereof.   The analysis method according to claim 1, wherein a main component of the organic film is a silicone resin.   The said droplet contains the organic solvent, organic acid or its salt, inorganic acid or its salt, organic base or its salt, inorganic base, hydrogen peroxide, or these combination in Claim 1, Claim 2 or Claim 3 Analysis method described.   In the moving step, a holder having a surface facing the surface of the organic film and capable of moving parallel to the surface of the organic film is used, and the droplet is placed between the organic film and the facing surface of the holder. The analysis method according to any one of claims 1 to 4, wherein the movement is performed in a state where the gap is held.   The analysis method according to any one of claims 1 to 5, further comprising a step of removing at least a part of the liquid component in the droplet between the moving step and the analyzing step.   The analysis method according to any one of claims 1 to 6, wherein the organic film is a resist film, a resist lower layer film, a resist middle layer film, or a resist upper layer film.   The analysis method according to any one of claims 1 to 7, wherein a fluorescent X-ray analysis method is used in the analysis step.

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