JP5267824B2 - Measurement method of diffusion coefficient in polymer thin film by single fluorescent molecule detection method - Google Patents

Description

  The present invention relates to a method for measuring a diffusion coefficient of a low-molecular substance in a cured material by using a single fluorescent molecule detection method, and more specifically, from a sample containing a fluorescent molecule (fluorescent molecule-containing sample) in the sample. The present invention relates to a method for measuring a diffusion coefficient of a diffusing fluorescent molecule. In particular, there are problems with lattice defects such as vacancies and dislocations present in thin film materials, local crosslink density change, free volume distribution, polymer curing reaction behavior analysis, permeability of low-molecular substances in samples, resist patterning shape, etc. The present invention relates to a method for measuring a diffusion coefficient suitable for various electronic materials.

The diffusion coefficient of molecules diffusing in the cured film is currently measured by indirect observation because the diffusion signal is weak or trapping may occur in the middle.
For example, in order to detect lattice defects such as vacancies and dislocations existing in a substance such as an electronic material, a measurement method indirectly derived from the positron lifetime is disclosed as one of highly sensitive techniques (for example, , See Patent Documents 1 and 2).
In addition, an emission spectroscopic measurement apparatus using a high-resolution wavelength tunable laser, more specifically, a molecular spectrum can be measured by emission spectroscopy of a single molecule of a microluminescent object such as a functional dye molecule, an emission center, a quantum box, and a quantum beam. A single-molecule spectroscopic micro-optical device for measuring is disclosed (see Patent Document 3). In this method, single-molecule fluorescence analysis is performed by confining a crystalline dispersion medium containing fluorescent molecules in a disk-shaped minute sample cell having a diameter of about 4 μm and a height of about 0.5 μm. Although this method detects fluorescence from the sample cell collectively, it can be seen that fluorescent molecules are contained in the sample cell. However, since the fluorescence from the sample cell is detected collectively, the position of the molecule is detected. Cannot be specified.

The diffusion coefficient of fluorescent molecules in the polymerization process of styrene monomer in a solution and in a thin film state has been reported using a single fluorescent molecule detection method (see Non-Patent Document 1).
JP2007-178329 (Claims) JP 2003-215251 (Claims) JP-A-10-62347 (Claims) Angelwandte Chemie International Edition 2007, 46, 1-6

In the conventional diffusion coefficient measuring method described above, there is a problem that it is very difficult to accurately obtain the diffusion coefficient in the cured material.
For example, with the aim of measuring the diffusion coefficient of molecules, analysis of free volume distribution, change and behavior of molecules from positron and positronium lifetimes by pulse positron lifetime measurement, positron annihilation induced Auger electron spectroscopy, and low-pressure positron lifetime measurement However, these research areas are developing fields. Although a measurement method that requires an indirect film thickness of several micrometers or more has been proposed, the establishment of a thinner film and a direct measurement method exists as a demand of the industry.
In addition, it is known that the existing positron lifetime method has many problems such as poor S / N ratio and influence of the base substrate in the physical property evaluation with a thin film of micron order or less. Furthermore, the method for measuring the vacancy distribution indirectly derived from these positron lifetimes is very large in apparatus, and high performance can be obtained by using an accelerator, but it is expensive. If the positron source 120 is used, the cost can be suppressed relatively inexpensively, but the measurement takes time because the number of positrons is reduced. In the case of a thin film curable material of several microns or less, the influence from the base substrate is strong, and the signal intensity from the sample becomes relatively weak, so that measurement is difficult.

As described above, since the conventional method for measuring the diffusion coefficient is an indirect method for observing diffusion, a method capable of directly observing diffusion in a cured film or the like is extremely useful industrially.
The present invention has been made by paying attention to such circumstances, and its purpose is to solve the problems of the conventional method of measuring the diffusion coefficient, and to eliminate lattices such as vacancies and dislocations existing in the thin film material. Suitable for development and research of a wide range of electronic functional thin film materials such as defects, local crosslink density change, free volume distribution, polymer curing reaction behavior analysis, permeability of low molecular weight substances in samples, resist patterning shapes, etc. The diffusion coefficient in the material can be obtained with high accuracy. Another object of the present invention is to provide a diffusion coefficient measurement method that can simplify the structure and handling of the diffusion coefficient measurement system.

In order to achieve the above object, the diffusion coefficient measuring method according to the present invention has the following configuration.
That is, as a first aspect of the present invention, there is provided a method for identifying the diffusion process of a low molecular substance in a cured material by a single fluorescent molecule detection method combining an optical microscope and a CCD camera. A diffusion coefficient measurement method for obtaining a diffusion coefficient when rotating or translating in a curable material based on a change with time of a position of a bright spot by a fluorescent molecule in the curable material and a diffusion equation,
As a second aspect, the excitation of the fluorescent molecules uses a continuous oscillation Ar ion laser, He-Ne laser or semiconductor laser in the ultraviolet to visible range, and the laser light is transmitted with a high precision with a transmission bandwidth of 4 nm or less. A Peltier device that has a step of separating excitation light and fluorescence by transmitting through a laser line filter and a wavelength discrimination filter, and that can cool the CCD device to minus 70 ° C. to minus 200 ° C. to remove thermal noise with high accuracy. A method for measuring a diffusion coefficient according to the first aspect, characterized in that a CCD camera equipped with a cooled back-illuminated CCD detector is used;
As a third aspect, a fluorescent image is magnified using a 2 to 10 times relay lens to detect a single molecule fluorescent luminescent spot across a plurality of adjacent CCD elements, and the CCD detector provided in the CCD detector The corresponding observation range is set to 1 to 100 nm, the diffusion coefficient measuring method according to the second aspect,
As a fourth aspect, when acquiring position information of a bright spot, the temporal change of the position of the bright spot is determined according to a two-dimensional Gaussian fitting by a high-speed image analysis program. A method for measuring the diffusion coefficient according to any one of the above,
As a fifth aspect, the diffusion coefficient measurement according to any one of the first aspect to the fourth aspect, wherein the fluorescent molecule is a molecule that dissolves in a sample solvent and emits fluorescence in a wavelength range of 150 to 800 nm. Method,
As a sixth aspect, the method for measuring a diffusion coefficient according to the fifth aspect, wherein the fluorescent molecule is a perylene compound, a terylene compound, a carbocyanine compound, or a phenoxazine compound,
As a seventh aspect, the fluorescent molecule is N, N′-bis (2,6-dimethylphenyl) perylene-3,4,9,10-tetracarboxylic acid diimide, N- (2,6-diisopropylphenyl) -N. '-(N-octyl) -terylene-3,4,11,12-tetracarboxylic acid diimide, NN'-bis (2,6-diisopropylphenyl) terylene-3,4,11,12-tetracarboxylic acid With diimide, 1,1′-dioctadecyl-3,3,3 ′, 3′-tetramethylindocarbocyanine perchlorate, or 9- (diethylamino) -5H-benzo (a) phenoxazin-5-one A method for measuring the diffusion coefficient according to the sixth aspect,
As an eighth aspect, the method for measuring a diffusion coefficient according to any one of the first aspect to the seventh aspect, wherein the curable material is a material obtained by thermosetting a thermosetting film forming composition,
As a ninth aspect, the thermosetting film-forming composition includes a thermosetting monomer and / or a thermosetting resin having at least one crosslinking reactive group, and a method for measuring a diffusion coefficient according to the eighth aspect,
As a tenth aspect, the thermosetting film-forming composition further includes a crosslinking agent and a solvent, the diffusion coefficient measuring method according to the ninth aspect,
As a eleventh aspect, the method for measuring a diffusion coefficient according to any one of the first aspect to the seventh aspect, wherein the curable material is a material obtained by photocuring a photocured film-forming composition,
As a twelfth aspect, the photocurable film-forming composition contains a photocurable monomer having at least one photocrosslinking reactive group, or a photocurable resin, and the diffusion coefficient measuring method according to the eleventh aspect,
As a thirteenth aspect, the photocured film-forming composition further includes a photoreactive initiator and a solvent, the method for measuring a diffusion coefficient according to the twelfth aspect, and
As a fourteenth aspect, the curable material is formed of a photoresist film used in a lithography process for manufacturing a semiconductor device or a cured film forming composition used for a photoresist underlayer film. It is the measuring method of the diffusion coefficient of any one of them.

The method for measuring the diffusion coefficient of the present invention is based on observing fluorescence from a sample in a nanometer space by expanding the space through an objective lens, and has a high spatial resolution (in principle, 1 nm, usually 10 nm to 40 nm). ), The diffusion coefficient of the substance in the polymer thin film can be obtained by tracking the time evolution of the position coordinates of the molecules in the polymer thin film.
In addition, by using the method for measuring the diffusion coefficient of the present invention, the free volume related to polymer properties such as viscoelasticity, glass transition Tg, diffusion, rotation / translation, gas permeability, and dielectric properties, and for each material The local environment in different polymers can be evaluated. That is, by using the measurement method of the present invention, the diffusion coefficient of the fluorescent molecules in the heat-cured or light-cured thin film curable material can be obtained with high accuracy, and lattices such as vacancies and dislocations existing in the material can be obtained. Suitable for development research of a wide range of electronic functional thin film materials such as defects, local crosslink density change, free volume distribution, curing reaction behavior analysis, permeability of low molecular weight substances in samples, resist poisoning characteristics, resist patterning shapes, etc. The diffusion coefficient in a hardened material can be easily obtained. And by using the value of the diffusion coefficient obtained by using the measurement method of the present invention, among other things, the gap fill material, antireflection film, and etching mask material formed on the semiconductor substrate applied in the advanced processing process Development of a resist underlayer film forming composition and a resist film forming composition can be performed.

The present invention is a method for measuring the diffusion coefficient of a low molecular weight substance in a cured material using a single fluorescent molecule detection method.
The curable material used in the present invention is preferably a cured film, and the cured film forming composition for forming the cured film is not particularly limited, but a thermosetting film using a thermosetting compound or a photocurable compound. A forming composition or a photocured film forming composition may be used.

[Thermosetting film forming composition]
In the present invention, a cured film obtained by thermally curing a thermosetting film-forming composition by heating can be used as a curing material used for measuring the diffusion coefficient.
The thermosetting film-forming composition used in the present invention obtains a cured film by heating and curing a thermosetting film-forming composition containing a thermosetting compound. The thermosetting film-forming composition may contain a solvent and, if necessary, a light-absorbing compound and an additive component. As said additive component, other components, such as a crosslinking agent (crosslinkable compound), a crosslinking catalyst (an acid, an acid generator, etc.), a rheology modifier, and surfactant, can be included.
The ratio of the solid content in the thermosetting film forming composition used in the present invention is not particularly limited as long as each component is uniformly dissolved in the solvent, but is, for example, 1 to 50% by mass, or 1 to 30% by mass or 1 to 25% by mass. Here, the solid content is obtained by removing the solvent component from all the components of the thermosetting film forming composition.

<Thermosetting compound>
As the thermosetting compound, a thermosetting monomer having at least one crosslinking reactive group, a thermosetting resin, or a mixture thereof is used. The thermosetting compound is particularly limited as long as it is a compound containing a component that is cured by heating, that is, a compound that can be cured by causing a crosslinking reaction by reacting a crosslinking group such as a hydroxyl group, an epoxy group, and a carboxyl group in the molecule. There is no.
Content of the thermosetting compound in solid content in the above-mentioned thermosetting film formation composition can be 50-100 mass%, 70-99 mass%, and 80-97 mass%.

  As a thermosetting compound contained in the thermosetting film forming composition used for the measuring method of the present invention, for example, a polymer containing a structural unit represented by the following formula (1) or a monomer for producing the polymer is included. be able to.

In the above formula (1), R ¹ represents a hydrogen atom, a methyl group, or a halogen atom such as a chlorine atom or a bromine atom, R ² represents a hydrogen atom or a hydroxyl group, and p is a number of 1, 2, 3 or 4. Q represents the number 0, 1, 2 or 3.

The polymer having the structural unit represented by the above formula (1) can be produced by polymerization of an acrylic monomer having an addition polymerizable unsaturated bond.
Specifically, a monomer capable of forming a polymer having a structural unit represented by the above formula (1) in an organic solvent (concentration of 10 to 60% in the solvent), and a chain transfer agent (if necessary) ( 1 to 10% based on the mass of the monomer is dissolved, and then a polymerization initiator (1 to 10% based on the mass of the monomer) is added to perform a polymerization reaction, and then a polymerization stopper (based on the mass of the monomer). 0.01 to 0.2%) can be added.
Examples of the organic solvent used in the polymerization reaction include propylene glycol monomethyl ether, propylene glycol monopropyl ether, ethyl lactate, and dimethylformamide, chain transfer agents such as dodecanethiol and dodecylthiol, and polymerization initiators such as azo Examples thereof include bisisobutyronitrile and azobiscyclohexanecarbonitrile, and examples of the polymerization terminator include 4-methoxyphenol.
The reaction temperature for the above polymerization reaction is appropriately selected from 60 to 90 ° C. and the reaction time is from 6 to 24 hours.

  Specific examples of the monomer capable of forming the polymer having the structural unit represented by the above formula (1) include, for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate. 2,3-dihydroxypropyl acrylate, 2-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, and the like.

As the polymer contained in the thermosetting film forming composition used in the present invention, a polymer produced using one kind of monomer capable of forming a polymer having the structural unit represented by the formula (1), or the monomer Copolymers produced by using two or more of these, and a mixture of these polymers can be used.
Specific examples of such a polymer include, for example, poly (2-hydroxyethyl) acrylate, poly (2-hydroxyethyl) methacrylate, poly (2-hydroxypropyl) acrylate, poly (2-hydroxypropyl) methacrylate; Copolymer of hydroxyethyl acrylate and 2-hydroxyethyl methacrylate, copolymer of 2-hydroxyethyl acrylate and 2-hydroxypropyl methacrylate, copolymer of 2-hydroxypropyl acrylate and 2-hydroxyethyl methacrylate, 2-hydroxyethyl Examples thereof include a copolymer of acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl acrylate. Moreover, these polymer mixtures can be used.

  Furthermore, in the cured film forming composition used in the present invention, a polymer containing a structural unit represented by the above formula (1) and a structural unit represented by the following formula (2) can also be used.

In the above formula (2), R ¹ represents a hydrogen atom, a methyl group, or a halogen atom such as a chlorine atom or a bromine atom, and R ³ represents an alkyl group having 1 to 8 carbon atoms, a benzyl group, or at least one fluorine atom. Represents an alkyl group having 1 to 6 carbon atoms substituted with a chlorine atom or a bromine atom, or an alkyl group having 1 to 6 carbon atoms substituted with at least one alkoxy group having 1 to 6 carbon atoms .

Specific examples of R ³ include, for example, a linear alkyl group such as a methyl group, an ethyl group, a normal propyl group, and a normal hexyl group, a branched alkyl group such as an isopropyl group, an isobutyl group, and a 2-ethylhexyl group, Cyclopentyl group, cycloaliphatic alkyl group such as cyclohexyl group, trichloroethyl group, alkyl group substituted with halogen atom such as trifluoroethyl group, alkoxyalkyl group such as methoxyethyl group, ethoxyethyl group, and benzyl The group can be mentioned.

Since the hydroxyl group contained in the structural unit represented by the formula (1) is a crosslinking-forming substituent, it can cause a crosslinking reaction with the crosslinking agent. The polymer contained in the thermosetting composition used in the present invention is preferably capable of undergoing a crosslinking reaction with a crosslinking agent. Therefore, the structural unit represented by the formula (1) has a ratio of at least 0.10 in the polymer. It is preferable that it is contained.
Therefore, in the polymer composed of the structural units represented by the formulas (1) and (2), the ratio of the structural units represented by the formula (1) (molar ratio of the structural units) is 0.10 or more. For example, 0.10 to 0.95, for example 0.20 to 0.90, 0.30 to 0.80, and for example 0.40 to 0.70.

  Specific examples of monomers capable of forming a polymer containing the structural unit represented by the formula (2) include, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, normal propyl acrylate, normal propyl methacrylate, isopropyl acrylate, isopropyl Methacrylate, normal butyl acrylate, normal butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, normal pentyl methacrylate, normal hexyl methacrylate, cyclohexyl methacrylate, normal octyl acrylate, 2-ethylhexyl methacrylate, cyclohexylmethyl methacrylate, benzyl acrylate, benzyl methacrylate, 2-chloroethyl Acrylate, 2 Chloroethyl methacrylate, 2-fluoroethyl methacrylate, 2-bromoethyl methacrylate, 2,2,2-trifluoroethyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,2-tribromoethyl acrylate, 2 , 2,2-tribromoethyl methacrylate, 2,2,2-trichloroethyl methacrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, hexafluoroisopropyl methacrylate, 2-methoxyethyl acrylate, Examples include 2-methoxyethyl methacrylate, 2-ethoxyethyl acrylate, 2-ethoxyethyl methacrylate, 2-normal butoxyethyl methacrylate, and 3-methoxybutyl methacrylate.

The polymer containing the structural unit represented by the above formula (1) and the structural unit represented by the following formula (2) contained in the cured film forming composition used in the present invention is represented by the above (1). A copolymer which is produced from one type of monomer capable of forming a polymer containing a structural unit and one type of monomer capable of forming a polymer containing the structural unit represented by (2) above. it can. Moreover, from the combination of the monomer which can form the polymer containing the structural unit represented by 2 or more types of Formula (1), and the monomer which can form the polymer containing the structural unit represented by 2 or more types of Formula (2) Copolymers produced and mixtures of these polymers can also be used.
Specific examples of such a polymer include a copolymer of 2-hydroxyethyl acrylate and methyl acrylate, a copolymer of 2-hydroxyethyl acrylate and ethyl acrylate, and a copolymer of 2-hydroxyethyl acrylate and isopropyl acrylate. Copolymer of 2-hydroxyethyl acrylate and normal butyl acrylate, copolymer of 2-hydroxyethyl methacrylate and methyl acrylate, copolymer of 2-hydroxyethyl methacrylate and ethyl acrylate, 2-hydroxyethyl methacrylate and normal propyl acrylate Copolymer of 2-hydroxyethyl methacrylate and isobutyl acrylate, 2-hydroxyethyl acrylate Copolymer of 2-hydroxyethyl acrylate and ethyl methacrylate, copolymer of 2-hydroxyethyl acrylate and isopropyl methacrylate, copolymer of 2-hydroxyethyl acrylate and isobutyl methacrylate, 2 -Copolymer of hydroxyethyl methacrylate and methyl methacrylate, copolymer of 2-hydroxyethyl methacrylate and ethyl methacrylate, copolymer of 2-hydroxyethyl methacrylate and normal propyl methacrylate, copolymer of 2-hydroxyethyl methacrylate and normal butyl methacrylate Polymerized polymer, copolymer of 2-hydroxypropyl acrylate and methyl acrylate, 2-hydride Copolymer of xylpropyl acrylate and ethyl acrylate, copolymer of 2-hydroxypropyl acrylate and normal propyl acrylate, copolymer of 2-hydroxypropyl acrylate and normal butyl acrylate, copolymer of 2-hydroxybutyl acrylate and methyl acrylate Polymer, copolymer of 2-hydroxybutyl acrylate and ethyl acrylate, copolymer of 2-hydroxybutyl acrylate and normal propyl acrylate, copolymer of 2-hydroxybutyl acrylate and normal butyl acrylate, 2-hydroxypropyl acrylate and 2 , 2,2-Trifluoroethyl methacrylate copolymer, 2-hydroxyethyl methacrylate and 2,2,2 -Copolymer of trifluoroethyl methacrylate, copolymer of 2-hydroxyethyl methacrylate and 2,2,2-trichloroethyl methacrylate, copolymer of 2-hydroxyethyl acrylate and 2-fluoroethyl methacrylate, 2-hydroxyethyl Copolymer of methacrylate and 2-chloroethyl methacrylate, copolymer of 2-hydroxyethyl methacrylate and 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, 2-hydroxyethyl acrylate and 2,2 , 2-tribromoethyl methacrylate copolymer, 2-hydroxyethyl methacrylate and 2-ethoxyethyl methacrylate copolymer, 2-hydroxyethyl acrylate and benzyl methacrylate Copolymer of 2-hydroxyethyl acrylate, copolymer of 2-hydroxyethyl methacrylate and methyl acrylate, copolymer of 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate and methyl acrylate, 2-hydroxyethyl acrylate and 2 -Copolymer of hydroxyethyl methacrylate and methyl methacrylate, Copolymer of 2-hydroxyethyl acrylate, ethyl methacrylate and 2,2,2-trifluoroethyl methacrylate, 2-hydroxyethyl methacrylate, 2-ethoxyethyl methacrylate and normal hexyl Copolymer of methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate and ethyl methacrylate When the copolymer or the like of 2,2,2-trifluoroethyl methacrylate.

  The weight average molecular weight (in terms of polyethylene) of the polymer contained in the thermosetting film forming composition used in the present invention is 1,000 to 2,000,000, or 1,500 to 200,000, or 1,500. It is -50,000, or can be used in the range of 1500-30,000.

<Crosslinking agent>
The thermosetting film forming composition used in the present invention can contain a crosslinking agent as required. By including a cross-linking agent, for example, when a thermosetting film forming composition is formed as a gap fill material, a cross-linking reaction occurs when the composition is applied onto a substrate and baked. Due to this crosslinking reaction, the formed thermosetting film becomes strong, and an organic solvent commonly used in resist underlayer film forming compositions such as a photoresist or an antireflection film, such as ethylene glycol. Monomethyl ether, ethyl cellosolve acetate, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, methyl ethyl ketone, cyclohexanone, ethyl 2-hydroxypropionate, 2-hydroxy-2 -A cured film having low solubility in ethyl methyl propionate, ethyl ethoxy acetate, methyl pyruvate, ethyl lactate, butyl lactate and the like. That is, by including a crosslinking agent, the thermosetting film formed from the thermosetting film-forming composition used in the present invention causes intermixing with the photoresist or antireflection film applied or formed on the upper layer in some cases. It will not be.

Such a crosslinking agent is not particularly limited, but a crosslinking agent having at least two crosslinking-forming substituents is preferably used.
Examples thereof include melamine compounds and substituted urea compounds having a cross-linking substituent such as a methylol group or a methoxymethyl group. Specifically, it is a compound such as methoxymethylated glycoluril or methoxymethylated melamine, and examples thereof include tetramethoxymethylglycoluril, tetrabutoxymethylglycoluril, and hexamethoxymethylmelamine. In addition, compounds such as tetramethoxymethylurea and tetrabutoxymethylurea are also included.
These cross-linking agents may cause a cross-linking reaction by self-condensation, but may also cause a cross-linking reaction with a cross-linking substituent contained in the aforementioned polymer, for example, a hydroxyl group in the formula (1).
Content of a crosslinking agent is 5 mass% or less in solid content, for example, is 0.01-5 mass%, for example, is 0.04-5 mass%.

<Crosslinking catalyst>
In the thermosetting film forming composition used in the present invention, p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium-p-toluenesulfonic acid, salicylic acid, sulfosalicylic acid, citric acid is used as a catalyst for promoting the crosslinking reaction. Acid compounds such as acid, benzoic acid and hydroxybenzoic acid; or 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, bis (4-t-butylphenyl) iodonium Acid generators such as trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, phenyl-bis (trichloromethyl) -s-triazine, benzoin tosylate, N-hydroxysuccinimide trifluoromethanesulfonate, and the like can be added.

  The amount of the acid or acid generator compound added varies depending on the type of polymer, the type of crosslinking agent, the amount added, and the like, but is 5 mass% or less in the solid content, for example, 0.01 to 5 mass. %, For example, 0.04 to 5% by mass.

<Solvent>
The thermosetting film-forming composition of the present invention is preferably used in a solution state in which each component (hereinafter referred to as “solid content”) such as the thermosetting compound is dissolved in a solvent. As the solvent, any solvent can be used as long as it can dissolve a solid content to form a uniform solution.
For example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, Toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3- Methyl methoxypropionate, 3-methoxyp Ethyl pionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, N-dimethylformamide, N-dimethylacetamide, dimethylsulfo Xoxide, N-methylpyrrolidone, etc. can be mentioned. These solvents can be used alone or in combination of two or more.
As the solvent, a solvent having a boiling point of 80 to 250 ° C, 100 to 200 ° C, or 120 to 180 ° C is preferably used. When the boiling point of the solvent is low, a large amount of the solvent evaporates during the application of the thermosetting film-forming composition, resulting in an increase in viscosity and a decrease in applicability. When the boiling point of the solvent is high, it can be considered that time is required for drying after application of the thermosetting film-forming composition.
The solvent can be used in such an amount that the concentration of the solid content of the thermosetting film-forming composition is, for example, 1 to 50% by mass, or 1 to 30% by mass, or 1 to 25% by mass. Here, the solid content is obtained by removing the solvent component from all the components of the thermosetting film forming composition.

<Curing film obtained from thermosetting film forming composition>
The above-mentioned thermosetting film-forming composition is applied onto a substrate by an appropriate application method such as a spinner or a coater, and then heated to form a cured film. The heating conditions are appropriately selected from heating temperatures of 80 ° C. to 250 ° C. and heating times of 0.3 to 60 minutes. Preferably, the heating temperature is 130 ° C. to 250 ° C., and the heating time is 0.5 to 5 minutes.

[Photocured film forming composition]
Further, in the present invention, a cured film obtained by curing the photocured film-forming composition by light irradiation in addition to the cured film obtained from the above-mentioned thermosetting film-forming composition as a cured material used for measurement of the diffusion coefficient. Can be used.
As the photocured film forming composition used in the present invention, a photocured film forming composition used for a lower layer film used as a lower layer of a photoresist in a lithography process for manufacturing a semiconductor device can be used.
Such a photocurable film-forming composition contains a photocurable compound, that is, a photocurable monomer having at least one photocrosslinking reactive group, or a photocurable resin, and photocured to form a cured film. obtain. The photocured film-forming composition may further contain a photoreactive initiator and a solvent, and may contain other components such as a surfactant and a sensitizer as necessary.
The ratio of the solid content in the photocurable film-forming composition used in the present invention is, for example, 0.5 to 50% by mass, or 3 to 40% by mass, or 10 to 30% by mass. Here, the solid content is obtained by removing the solvent component from all components of the photocured film-forming composition.

<Photocurable compound>
The photocurable compound (photocurable monomer, photocurable resin) is a compound having one or more polymerizable sites (photocrosslinking reactive groups) in the molecule that are photopolymerized by the action of a photoreactive initiator described later. If there is no particular limitation. From the viewpoint of forming a cured film having high solvent resistance, a compound having two or more photopolymerizable sites, for example, 2 to 6, or 3 to 4, is a photocurable film-forming composition of the present invention. It is preferably used as a photocurable compound.
Content of the photocurable compound in solid content in the above-mentioned photocuring film forming composition can be 50-100 mass%, 70-99 mass%, and 80-95 mass%.

As a photopolymerizable site | part contained in the said photocurable compound, the ethylenically unsaturated bond which is a radically polymerizable site | part is mentioned, for example. Examples of the photopolymerizable moiety include a cyclic ether structure such as an epoxy ring and an oxetane ring which is a cationic polymerizable moiety, a vinyl ether structure, a vinyl thioether structure, and the like.
As the photocurable compound, a compound that is liquid at room temperature (about 20 ° C.) is preferably used. The molecular weight (weight average molecular weight in terms of polyethylene) of the photocurable compound is preferably 100 or more, for example, 100 to 2,000, or 150 to 1,500, or 300 to 1,000. Or 400-800.

The photocurable compound having an ethylenically unsaturated bond is not particularly limited, and examples thereof include unsaturated carboxylic acid compounds such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid and phthalic acid.
In addition, unsaturated carboxylic acid ester compounds or unsaturated carboxylic acid amide compounds derived from these unsaturated carboxylic acid compounds and alcohol compounds or amine compounds can be mentioned, for example, acrylic acid ester compounds, methacrylic acid ester compounds, Itaconic acid ester compounds, crotonic acid ester compounds, maleic acid ester compounds, phthalic acid ester compounds, acrylic acid amide compounds, methacrylic acid amide compounds, itaconic acid amide compounds, crotonic acid amide compounds, maleic acid amide compounds, phthalic acid amide compounds, etc. Can be mentioned.

  The alcohol compound used in the unsaturated carboxylic acid ester compound or unsaturated carboxylic acid amide compound is not particularly limited, but ethylene glycol, triethylene glycol, tetraethylene glycol, tris (2-hydroxylethyl) isocyanuric acid, triethanol. Examples thereof include polyol compounds having 2 to 6 hydroxyl groups such as amine and pentaerythritol. The amine compound is not particularly limited, but ethylenediamine, diaminocyclohexane, diaminonaphthalene, 1,4-bis (aminomethyl) cyclohexane, 3,3 ′, 4,4′-tetraaminobiphenyl, and tris (2- Examples thereof include polyamine compounds having 2 to 6 primary or secondary amino groups, such as (aminoethyl) amine.

  Accordingly, specific examples of the photocurable compound having an ethylenically unsaturated bond include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and tetraethylene glycol di (meth). Acrylate, nonaethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, nonapropylene glycol di (meth) acrylate, polypropylene glycol di ( (Meth) acrylate, 2,2-bis [4- (acryloxydiethoxy) phenyl] propane, 2,2-bis [4- (methacryloxydiethoxy) phenyl] propane 3-phenoxy-2-propanoyl acrylate, 1,6-bis (3-acryloxy-2-hydroxypropyl) -hexyl ether, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerol tri (Meth) acrylate, tris- (2-hydroxylethyl) -isocyanuric acid ester (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meta ) Acrylate and the like. Here, for example, ethylene glycol di (meth) acrylate means ethylene glycol diacrylate and ethylene glycol dimethacrylate.

  As the photocurable compound having an ethylenically unsaturated bond in the present invention, in addition to the above-mentioned compounds, urethane compounds and polyvalent epoxies obtainable by reaction of polyvalent isocyanate compounds and hydroxyalkyl unsaturated carboxylic acid ester compounds. Mention may also be made of compounds obtainable by reaction of a compound with a hydroxyalkyl unsaturated carboxylic acid ester compound, diallyl ester compounds such as diallyl phthalate, and divinyl compounds such as divinyl phthalate.

Examples of the photocurable compound having a cationic polymerizable moiety include compounds having a cyclic ether structure such as an epoxy ring and an oxetane ring, a vinyl ether structure, a vinyl thioether structure, and the like.
The photocurable compound having an epoxy ring is not particularly limited, and compounds having 1 to 6 or 2 to 4 epoxy rings can be used. For example, a diol compound, a triol compound, a dicarboxylic acid can be used. Examples of compounds having two or more glycidyl ether structures or glycidyl ester structures that can be produced from compounds having two or more hydroxyl groups or carboxyl groups such as acid compounds and tricarboxylic acid compounds and glycidyl compounds such as epichlorohydrin Can do.
Specific examples of the photocurable compound having an epoxy ring include 1,4-butanediol diglycidyl ether, 1,2-epoxy-4- (epoxyethyl) cyclohexane, glycerol triglycidyl ether, diethylene glycol diglycidyl ether, 2, 6-diglycidylphenyl glycidyl ether, 1,1,3-tris [p- (2,3-epoxypropoxy) phenyl] propane, 1,2-cyclohexanedicarboxylic acid diglycidyl ester, 4,4′-methylenebis (N, N-diglycidylaniline), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, trimethylolethane triglycidyl ether, triglycidyl-p-aminophenol, tetraglycidylmetaxylenediamine, Tetraglycidyldiaminodiphenylmethane, tetraglycidyl-1,3-bisaminomethylcyclohexane, bisphenol-A-diglycidyl ether, bisphenol-S-diglycidyl ether, pentaerythritol tetraglycidyl ether resorcinol diglycidyl ether, diglycidyl phthalate, neo Pentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, tetrabromobisphenol-A-diglycidyl ether, bisphenol hexafluoroacetone diglycidyl ether, pentaerythritol diglycidyl ether, tris- (2,3-epoxypropyl) isocyanurate, mono Allyl diglycidyl isocyanurate, diglycerol polydiglycidyl a , Pentaerythritol polyglycidyl ether, 1,4-bis (2,3-epoxypropoxyperfluoroisopropyl) cyclohexane, sorbitol polyglycidyl ether, trimethylolpropane polyglycidyl ether, resorcin diglycidyl ether, 1,6-hexanediol Diglycidyl ether, polyethylene glycol diglycidyl ether, phenyl glycidyl ether, p-tertiary butyl phenyl glycidyl ether, adipic acid diglycidyl ether, o-phthalic acid diglycidyl ether, dibromophenyl glycidyl ether, 1,2,7,8- Diepoxyoctane, 1,6-dimethylolperfluorohexane diglycidyl ether, 4,4′-bis (2,3-epoxypropoxyperfluoro Sopropyl) diphenyl ether, 2,2-bis (4-glycidyloxyphenyl) propane, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexyloxirane, 2- (3 4-epoxycyclohexyl) -3 ', 4'-epoxy-1,3-dioxane-5-spirocyclohexane, 1,2-ethylenedioxy-bis (3,4-epoxycyclohexylmethane), 4', 5'- Epoxy-2′-methylcyclohexylmethyl-4,5-epoxy-2-methylcyclohexanecarboxylate, ethylene glycol-bis (3,4-epoxycyclohexanecarboxylate), bis- (3,4-epoxycyclohexylmethyl) adipate, And bis (2,3-epoxy Kuropenchiru) ether and the like.

  The photocurable compound having an oxetane ring is not particularly limited, and compounds having 1 to 6 or 2 to 4 oxetane rings can be used. Specifically, 3-ethyl- 3-hydroxymethyloxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3,3-diethyloxetane, and 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 1,4-bis ((( 3-ethyl-3-oxetanyl) methoxy) methyl) benzene, di ((3-ethyl-3-oxetanyl) methyl) ether, pentaerythritol tetrakis ((3-ethyl-3-oxetanyl) methyl) ether, etc. Can do.

  The photocurable compound having a vinyl ether structure is not particularly limited, but compounds having 1 to 6 or 2 to 4 vinyl ether structures can be used. Specifically, vinyl-2- Chloroethyl ether, vinyl-normal butyl ether, 1,4-cyclohexanedimethanol divinyl ether, vinyl glycidyl ether, bis (4- (vinyloxymethyl) cyclohexylmethyl) glutarate, tri (ethylene glycol) divinyl ether, adipic acid divinyl ester, Diethylene glycol divinyl ether, tris (4-vinyloxy) butyl trimellrate, bis (4- (vinyloxy) butyl) terephthalate, bis (4- (vinyloxy) butyl isophthalate, ethylene glycol divinyl ether, 1, -Butanediol divinyl ether, tetramethylene glycol divinyl ether, tetraethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, trimethylolethane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, Examples include tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, and cyclohexanedimethanol divinyl ether.

  Moreover, as a photocurable compound having a cationically polymerizable site, in addition to the above compound, a structural unit containing an epoxy group represented by the formula (3) having at least one reactive group capable of cationic polymerization, or A polymer compound having a structural unit containing an oxetane ring represented by the formula (4) can be used.

  In formula (3), P represents a linking group constituting the polymer main chain, and Q represents a direct bond or a linking group.

  In formula (4), P represents a linking group constituting the polymer main chain, and Q represents a direct bond or a linking group.

<Photoreactive initiator>
The photoreactive initiator contained in the photocurable film-forming composition used in the present invention is not particularly limited as long as it has a function capable of initiating photopolymerization of the photocurable compound by light irradiation. For example, a compound that generates an acid (Bronsted acid or Lewis acid), a base, a radical, or a cation by light irradiation can be used as a photoreactive initiator.
Specifically, a compound capable of generating an active radical by light irradiation and causing radical polymerization of the photocurable compound, that is, a photo radical polymerization initiator, and a cationic species such as protonic acid and carbon cation by light irradiation. The compound which can raise | generate cationic polymerization of the said photocurable compound, ie, a photocationic polymerization initiator, etc. can be mentioned.

Light irradiation can be performed using, for example, light having a wavelength of 150 nm to 1000 nm, 193 to 700 nm, or 300 to 600 nm. The photo-radical polymerization initiator to produce active radicals by exposure 1 to 2,000 mJ / cm ^2, or 10~1500mJ / cm ^2, or 50~1000mJ / cm ^2, or cationic photopolymerization initiator to produce cationic species, photoreactive It is preferably used as a sex initiator.

Examples of the photo radical polymerization initiator include organic azide compounds, imidazole compounds, diazo compounds, bisimidazole compounds, N-aryl glycine compounds, titanocene compounds, aluminate compounds, organic peroxides, N-alkoxy pyridinium salt compounds, and Examples include thioxanthone compounds.
Examples of azide compounds include p-azidobenzaldehyde, p-azidoacetophenone, p-azidobenzoic acid, p-azidobenzalacetophenone, 4,4′-diazidochalcone, 4,4′-diazidodiphenyl sulfide, and 2, Examples include 6-bis (4′-azidobenzal) -4-methylcyclohexanone.
Examples of the diazo compound include 1-diazo-2,5-diethoxy-4-p-tolylmercaptobenzeneborofluoride, 1-diazo-4-N, N-dimethylaminobenzene chloride, and 1-diazo-4-N, Examples thereof include N-diethylaminobenzeneborofluoride.
Examples of the bisimidazole compound include 2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetrakis (3,4,5-trimethoxyphenyl) 1,2′-bisimidazole, and 2 , 2'-bis (o-chlorophenyl) 4,5,4 ', 5'-tetraphenyl-1,2'-bisimidazole and the like.
As titanocene compounds, dicyclopentadienyl-titanium-dichloride, dicyclopentadienyl-titanium-bisphenyl, dicyclopentadienyl-titanium-bis (2,3,4,5,6-pentafluorophenyl) Dicyclopentadienyl-titanium-bis (2,3,5,6-tetrafluorophenyl), dicyclopentadienyl-titanium-bis (2,4,6-trifluorophenyl), dicyclopentadienyl -Titanium-bis (2,6-difluorophenyl), dicyclopentadienyl-titanium-bis (2,4-difluorophenyl), bis (methylcyclopentadienyl) -titanium-bis (2,3,4, 5,6-pentafluorophenyl), bis (methylcyclopentadienyl) -titanium-bis (2,3,5,6-tetrafluoro Enyl), bis (methylcyclopentadienyl) -titanium-bis (2,6-difluorophenyl), and dicyclopentadienyl-titanium-bis (2,6-difluoro-3- (1H-pyrrol-1-) Yl) -phenyl) and the like.

  Examples of photo radical polymerization initiators include 1,3-di (tert-butyldioxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetrakis (tert-butyldioxycarbonyl) benzophenone, 3-phenyl- 5-isoxazolone, 2-mercaptobenzimidazole, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 2-benzyl-2-dimethylamino-1- Mention may also be made of (4-morpholinophenyl) -butanone and the like.

Photocationic polymerization initiators include sulfonic acid esters, sulfonimide compounds, disulfonyldiazomethane compounds, dialkyl-4-hydroxysulfonium salts, arylsulfonic acid-p-nitrobenzyl esters, silanol-aluminum complexes, (η6-benzene) ( (η5-cyclopentadienyl) iron (II) and the like.
Examples of the sulfonimide compound include N- (trifluoromethanesulfonyloxy) succinimide, N- (nonafluoro-normalbutanesulfonyloxy) succinimide, N- (camphorsulfonyloxy) succinimide, N- (trifluoromethanesulfonyloxy) naphthalimide, and the like. Is mentioned.
Examples of the disulfonyldiazomethane compound include bis (trifluoromethylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (phenylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, and bis (2,4-dimethylbenzenesulfonyl). ) Diazomethane, methylsulfonyl-p-toluenesulfonyldiazomethane, and the like.

  Examples of the photocationic polymerization initiator include 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one.

In addition, aromatic iodonium salt compounds, aromatic sulfonium salt compounds, aromatic diazonium salt compounds, aromatic phosphonium salt compounds, triazine compounds and iron arene complex compounds can be used as photo radical polymerization initiators or photo cationic polymerization initiators. Can also be used.
Aromatic iodonium salt compounds include diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-normal butanesulfonate, diphenyliodonium perfluoro-normaloctanesulfonate, diphenyliodonium camphorsulfonate, bis (4-tert- Examples thereof include butylphenyl) iodonium camphorsulfonate and bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate.
Examples of the aromatic sulfonium salt compound include triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoronormal butane sulfonate, triphenylsulfonium camphorsulfonate, triphenylsulfonium trifluoromethanesulfonate, and the like.

In the photocurable film-forming composition of the present invention, the photoreactive initiator can be used alone or in combination of two or more.
As content of the photocurable compound and photoreactive initiator in the photocurable film formation composition of this invention, a photoreactive initiator is 1-20 masses with respect to 100 mass parts of photocurable compounds, for example. Part, or 3 to 10 parts by mass. When the amount of the photoreactive initiator is less than this, the polymerization reaction does not proceed sufficiently, and the photocured film may have insufficient hardness and wear resistance. If the amount of the photoreactive initiator is larger than this, curing may occur only in the vicinity of the surface of the photocured film, and it may be difficult to completely cure the inside of the photocured film.

  In the photocurable film-forming composition of the present invention, when a compound having an ethylenically unsaturated bond, which is a radical polymerizable site, is used as the photocurable compound, the photoreactive initiator is used as the photoreactive initiator. An agent is preferably used. Moreover, when a compound having a vinyl ether structure, an epoxy ring or an oxetane ring, which is a cationically polymerizable site, is used as the photocurable compound, a photocationic polymerization initiator is preferably used as the photoreactive initiator.

<Other additives that can be contained>
In addition to the photocurable compound and the photoreactive initiator, the photocured film forming composition of the present invention includes a surfactant, a sensitizer, an amine compound, a polymer compound, an antioxidant, A polymerization inhibitor, a surface modifier, a defoaming agent, etc. can be added.

The surfactant can suppress the occurrence of pinholes and installations, and can improve the applicability of the photocured film-forming composition. Examples of the surfactant include polyoxyethylene alkyl ether compounds such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether and polyoxyethylene oleyl ether, polyoxyethylene octyl phenol ether and polyoxyethylene nonyl phenol ether and the like. Oxyethylene alkyl allyl ether compounds, polyoxyethylene / polyoxypropylene block copolymer compounds, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan trioleate, sorbitan trisoleate and other sorbitan fatty acid ester compounds, polyoxy Ethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxye Polyoxyethylene sorbitan fatty acid ester compounds such as alkylene sorbitan monostearate and polyoxyethylene sorbitan tristearate and the like. In addition, trade names F-top EF301, EF303, EF352 (manufactured by Gemco (formerly Tochem Products)), trade names Megafuck F171, F173, R-08, R-30 (manufactured by DIC Corporation) Fluorosurfactants such as Fluorard FC430, FC431 (manufactured by Sumitomo 3M Limited), trade names Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (Asahi Glass Co., Ltd.) And organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.).
When a surfactant is used, the addition amount thereof is, for example, 0.1 to 5 parts by mass or 0.5 to 2 parts by mass with respect to 100 parts by mass of the photocurable compound.

A sensitizer can be used to increase the sensitivity of the photoreactive initiator to light. Examples of the sensitizer include 2,6-diethyl-1,3,5,7,8-pentamethylpyromethene-BF ₂ complex and 1,3,5,7,8-pentamethylpyromethene-BF _2. Pyrromethene complex compounds such as complexes, xanthene dyes such as eosin, ethyl eosin, erythrosine, fluorescein and rose bengal, 1- (1-methylnaphth [1,2-d] thiazole-2 (1H) -ylidene-4- (2 , 3,6,7) Tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) -3-buten-2-one, 1- (3-methylbenzothiazol-2 (3H) -ylidene-4- Ketothiazoline compounds such as (p-dimethylaminophenyl) -3-buten-2-one, 2- (p-dimethylaminostyryl) -naphtho [1,2-d] thiazole, 2- [4- And styryl such as (p-dimethylaminophenyl) -1,3-butadienyl] -naphtho [1,2-d] thiazole, phenylbutadienyl heterocyclic compounds, etc. In addition, 2,4-diphenyl-6- (P-dimethylaminostyryl) -1,3,5-triazine, 2,4-diphenyl-6-(([2,3,6,7] tetrahydro-1H, 5H-benzo [ij] quinolidin-9-yl ) -1-ethen-2-yl) -1,3,5-triazonenanthryl-(([2,3,6,7] tetrahydro-1H, 5H-benzo [ij] quinolidin-9-yl)- 1-ethen-2-yl) ketone, 2,5-bis (p-dimethylaminocinnamylidene) cyclopentanone, 5,10,15,20 tetraphenylporphyrin and the like can also be mentioned as sensitizers. .
When a sensitizer is used, the addition amount is, for example, 0.1 to 20 parts by mass with respect to 100 parts by mass of the photocurable compound.

  The amine compound can be used to prevent a decrease in sensitivity due to oxygen inhibition of the photoreactive initiator. As the amine compound, various amine compounds such as an aliphatic amine compound and an aromatic amine compound can be used. When an amine compound is used, the addition amount is, for example, 0.1 to 10 parts by mass with respect to 100 parts by mass of the photocurable compound.

The polymer compound is a compound used for adjusting the refractive index, attenuation coefficient, light absorption performance, and the like of the photocured film formed from the photocured film forming composition of the present invention. For example, by using a polymer compound having a benzene ring, the light absorption performance of the photocured film with respect to ArF excimer laser (wavelength 193 nm) can be enhanced. For example, by using a polymer compound having a naphthalene ring or an anthracene ring, the absorption performance of the photocured film with respect to a KrF excimer laser (wavelength 248 nm) can be enhanced.
There is no restriction | limiting in particular as a polymer compound, The various polymer compound whose weight average molecular weights are about 1000-1 million can be used. Examples thereof include acrylate polymers, methacrylate polymers, novolak polymers, styrene polymers, polyamides, polyamic acids, polyesters and polyimides having a benzene ring, naphthalene ring or anthracene ring.
Further, in the lithography process for manufacturing a semiconductor device, it is also possible to use a polymer compound having excellent light absorption performance that is used for an antireflection film under the photoresist. By using such a polymer compound, the performance as an antireflection film of the lower layer film formed from the photocured film forming composition of the present invention can be enhanced.
When a polymer compound is used, the addition amount is, for example, 0.1 to 50 parts by mass with respect to 100 parts by mass of the photocurable compound.

<Solvent>
The photocurable film-forming composition of the present invention is preferably used in a solution state in which each component (hereinafter referred to as “solid content”) such as the photocurable compound is dissolved in a solvent. As the solvent, any solvent can be used as long as it can dissolve a solid content to form a uniform solution. For example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, Toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3- Methyl methoxypropionate, 3-methoxyp Ethyl pionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, N-dimethylformamide, N-dimethylacetamide, dimethylsulfo Xoxide, N-methylpyrrolidone, etc. can be mentioned. These solvents can be used alone or in combination of two or more.
As the solvent, a solvent having a boiling point of 80 to 250 ° C, 100 to 200 ° C, or 120 to 180 ° C is preferably used. When the solvent has a low boiling point, a large amount of the solvent evaporates during the application of the photocured film-forming composition, resulting in an increase in viscosity and a decrease in applicability. When the boiling point of the solvent is high, it can be considered that time is required for drying after application of the photocurable film-forming composition.
The solvent can be used in such an amount that the concentration of the solid content of the photocured film-forming composition is, for example, 0.5 to 50% by mass, or 3 to 40% by mass, or 10 to 30% by mass. . Here, the solid content is obtained by removing the solvent component from all components of the photocured film-forming composition.

<Hardened film obtained from photocured film forming composition>
A coating film is formed by applying the above-mentioned photocured film-forming composition onto a substrate by an appropriate coating method such as a spinner or a coater. The coating film can be subjected to a drying step as necessary before light irradiation. In particular, when a cured film-forming composition containing a solvent is used for forming a cured film, the drying step is performed. It is preferable to keep it.
When the drying process is heated at a high temperature (for example, 150 ° C. or higher), sublimation of solids contained in the coating film may occur and the device may be contaminated. There is no particular limitation if it is not a method.
The drying step can be performed, for example, by heating the substrate at 50 to 100 ° C. for 0.1 to 10 minutes on a hot plate. For example, it can carry out by air-drying at room temperature (about 20 degreeC).

  Next, light irradiation is performed on the coating film. The light irradiation can be used without particular limitation as long as it is a method capable of acting on the photoreactive initiator and causing polymerization of the photocurable compound. Light irradiation can be performed using, for example, light having a wavelength of 150 nm to 1000 nm, 193 to 700 nm, or 300 to 600 nm. For example, the ultra-high pressure mercury lamp, flash UV lamp, high pressure mercury lamp, low pressure mercury lamp, DEEP-UV (deep ultraviolet) lamp, xenon short arc lamp, short arc metal halide lamp, YAG laser excitation lamp, and xenon flash lamp Etc. can be used. For example, using an ultra-high pressure mercury lamp, 289 nm, 297 nm, 303 nm, 313 nm (j line), 334 nm, 365 nm (i line) in the ultraviolet region, 405 nm (h line), 436 nm (g line), 546 nm in the visible light region. The irradiation can be performed by irradiating all wavelengths from about 250 nm to about 650 nm including an emission line spectrum having a peak at a wavelength of 579 nm.

  By photoirradiation, cationic species and active radicals are generated from the photoreactive initiator in the coating film, and these cause a polymerization reaction of the photocurable compound in the coating film. As a result of this polymerization reaction, a cured film is formed on the substrate, and a thin film sample can be obtained.

[Diffusion coefficient measurement method]
The diffusion coefficient measurement method of the present invention is a method for identifying the diffusion action of a low-molecular substance in a cured material (for example, the cured film described above) by a single fluorescent molecule detection method combining an optical microscope and a CCD camera. . Specifically, the diffusion coefficient when the fluorescent molecule excited by the excitation light source (laser) rotates or translates in the material, the time-dependent change and diffusion of the bright spot position by the fluorescent molecule in the cured material (cured film) This is a method of measuring a diffusion coefficient obtained based on an equation.

The CCD camera may be a camera using a charge coupled device image sensor.
Further, as the excitation light source of the fluorescent molecule, a continuous oscillation Ar ion laser, He—Ne laser or semiconductor laser is used in the ultraviolet to visible range. By using a high-precision laser line filter having a transmission bandwidth of 4 nm or less for light from the laser, monochromaticity of excitation light at an extremely high excitation wavelength can be realized.
By using a highly accurate wavelength discrimination filter, it is possible to separate excitation light and fluorescence with extremely high accuracy.
In addition, by using a CCD camera equipped with a Peltier-cooled back-illuminated CCD detector, which can remove thermal noise with high accuracy by cooling the CCD element, high photodetection sensitivity with a single photon count level is possible. This realizes time-resolved single-molecule fluorescence imaging.

The cooling temperature of the CCD element is about minus 70 ° C. to minus 200 ° C., and in particular, it can be cooled to about minus 78 ° C. to minus 80 ° C. using dry ice.
The fluorescent image obtained by the above-mentioned operation is enlarged and photographed using a relay lens of 2 to 10 times, preferably about 5 times, so that a single molecule fluorescent luminescent spot is detected across a plurality of CCD elements, and the CCD is detected. The observation range (spatial resolution) corresponding to one detector element can be set to 1 to 100 nm, actually 10 to 40 nm, and specifically about 32.5 nm.

  Then, when acquiring the position information of the fluorescent bright spots derived from the single molecules found in the acquired fluorescent image in the single molecule fluorescent imaging device, two-dimensional Gaussian fitting is performed by a high-speed image analysis program, so that the molecules can be detected at high speed and with high accuracy. Position information can be determined.

The fluorescent molecule used in the method for measuring a diffusion coefficient of the present invention can be dissolved in a sample solvent (a solvent used in the cured film forming composition for forming a cured material (film) to be measured) and 150 Molecules that fluoresce in the wavelength region of ˜800 nm, preferably 400 to 800 nm are preferred.
Examples of these fluorescent molecules include perylene compounds such as N, N′-bis (2,6-dimethylphenyl) perylene-3,4,9,10-tetracarboxylic acid diimide; N- (2,6-diisopropylphenyl) -N '-(n-octyl) -terylene-3,4,11,12-tetracarboxylic acid diimide and NN'-bis (2,6-diisopropylphenyl) terylene-3,4,11,12-tetra Terylene compounds such as carboxylic acid diimides; Carbocyanine compounds such as 1,1′-dioctadecyl-3,3,3 ′, 3′-tetramethylindocarbocyanine perchlorate; or 9- (diethylamino) -5H— Phenoxazine compounds such as benzo (a) phenoxazin-5-one can be used.

  N, N′-bis (2,6-dimethylphenyl) perylene-3,4,9,10-tetracarboxylic acid diimide [N, N′-bis (2,6-dimethylphenyl) perylene-3,4 The chemical structure of 9,10-tetracarboxylic dimethyl] is represented by the following formula (k-1). The fluorescent molecule represented by the following formula (k-1) is described in, for example, US Pat. No. 6,143,905.

  N- (2,6-diisopropylphenyl) -N '-(n-octyl) -terylene-3,4,11,12-tetracarboxylic acid diimide [N- (2,6-Diisopropylphenyl) -N'- The chemical structure of (n-octyl) -terylene-3,4,11,12-tetracarboxidimide] is represented by the following formula (k-2).

  In addition, the above-described NN′-bis (2,6-diisopropylphenyl) terylene-3,4,11,12-tetracarboxylic acid diimide [N, N′-bis (2,6-diisopropylphenyl) terylene-3,4 , 11, 12-tetracarbboximide] is represented by the formula (k-3).

  The fluorescent molecules represented by the above formulas (k-2) and (k-3) are, for example, Chemistry & European Journal, Vol. 3, No. 2, pages 219 to 225, published in 1997 (Chemistry A European). Journal, Vol 3, No. 2, 219-225, 1997).

  Of the above 1,1′-dioctadecyl-3,3,3 ′, 3′-tetramethylindocarbocyanine perchlorate [1,1′-dioctadecyl-3,3,3 ′, 3′-tetramethyldocarbocyanine perchlorate] The chemical structure is represented by the following formula (k-4). The fluorescent molecule represented by the following formula (k-4) is described, for example, in the reagent catalog of Aldrich.

  The chemical structure of 9- (diethylamino) -5H-benzo (a) phenoxazin-5-one [9- (Diethylamino) -5H-benzo [a] phenoxazin-5-one] is represented by the following formula (k-5). expressed. The fluorescent molecule represented by the following formula (k-5) is described in, for example, Journal of Photochemistry and Photobiology A Chemistry 181 (2006) 99-105. Has been.

In the measurement method of the present invention, for example, the above-described fluorescent molecule is mixed in the cured film forming composition, and the cured film forming composition is applied to a substrate and cured, and used as a measurement sample (thin film sample). Can do.
The concentration of the fluorescent molecule in the cured film forming composition is about 1 × 10 ⁻⁵ to 1 × 10 ⁻¹² mol / liter, preferably about 1 × 10 ⁻⁹ mol / liter.
And the cured film forming composition containing the said fluorescent molecule is apply | coated by the spin coat method, the coater method etc. on the board | substrate, and it hardens | cures with the hardening method which combined thermosetting, photocuring, or those, for example, 10-3000 nm, or A thin film having a film thickness of about 20 to 1000 nm, 20 to 800 nm, or 20 to 200 nm can be obtained and used as a thin film sample.

  The substrate may be a glass substrate, a semiconductor substrate, a ceramic substrate, or the like. The substrate on which the thin film sample is formed is placed on a microscope stage, and a laser for exciting (emitting) fluorescent molecules present in the thin film sample. Receive irradiation.

A measurement apparatus in which the measurement method of the present invention is implemented is, for example, a single molecule fluorescence imaging apparatus shown in FIG. In this measurement apparatus, a continuous wave laser or a pulse laser ((1) in FIG. 1) is used as an excitation light source, and the excitation light is applied to an area of about 50 micrometers in diameter of the thin film sample (9) in an incident light optical arrangement. With this optical arrangement, a plurality of fluorescent molecules in the thin film sample (9) are excited simultaneously.
Fluorescence from a single molecule group in the thin film sample (9) is obtained by back-illuminated type EMCCD camera (11) (trade name Cascade 512B, manufactured by Roper Scientific) with the objective lens (7). An image is formed on the detection surface. Here, a Peltier element cooled back-illuminated CCD detector is mounted.
At this time, excitation light and fluorescence are clearly separated in the wavelength region, and an optical filter (Semrock, Razo Edge, edge filter for Raman spectroscopy, etc.) is used to detect only the fluorescence from the sample. In (1), (10)) is used. This filter functions as the wavelength discrimination filter described above.
In addition, in order to enhance monochromaticity of excitation light, laser line filter (2) (manufactured by Semrock, trade name Maxline laser line filter, etc.) is used to prevent the mixing of stray light of different wavelengths as much as possible. , Improve the S / N ratio of fluorescence detection.

  The single molecule image obtained by the CCD camera is a spot having a diameter of about 250 nm, and the spot size is determined by the performance of the optical microscope objective lens used. When an existing objective lens is used, even if it is the highest performance objective lens, the minimum spot diameter is limited to about half of the wavelength, that is, 200 to 300 nm due to the diffraction limit of light in the fluorescent image in the visible range. However, by fitting the obtained spot image with a two-dimensional Gaussian function and tracking the displacement of the barycentric coordinate, the position map of the molecule is determined with higher accuracy than the diffraction limit (200 to 300 nm) of the microscope. can do. In principle, the accuracy of estimating the position of the molecule can be achieved with an accuracy of 1 nm.

  The apparatus used in the measurement method of the present invention is characterized in that the diffusion of fluorescent molecules in a thin film can be observed directly and with high sensitivity using an optical microscope, and the diffusion coefficient can be measured. The apparatus used in the measurement method of the present invention can measure a thin film obtained by a film formation method that is actually used in a semiconductor manufacturing process.

  Since the diffusion coefficient measurement method according to the present invention is excellent in measurement accuracy as described above, the amount of volatile matter (solvent) contained in the sample is very small as in the case where the sample is a cured film forming composition. Even in this case, the diffusion coefficient of the fluorescent molecule can be obtained with high accuracy. From this point, it is particularly suitable for measurement of the diffusion coefficient of the fluorescent molecule in the curing process of the cured film forming composition and the diffusion coefficient of the fluorescent molecule after the composition is cured.

  For example, the diffusion phenomenon of low-molecular substances such as acid, photoacid generator, or reaction terminator in the photoresist and resist underlayer film at the interface between the photoresist and the resist underlayer film is closely related to the shape of the formed photoresist. There is a relationship. For this reason, by comparing and adjusting the diffusion coefficient of the fluorescent molecules in the photoresist and the diffusion coefficient of the fluorescent molecules in the resist underlayer film, the photoresist shape to be formed is changed from an undercut to a straight shape, and then to a footing. Development of a photoresist and a resist underlayer film that can control the shape is possible.

  An example in which this measurement apparatus is used as a resist underlayer film in which a cured film measured according to the present invention is used in a lithography process for manufacturing a semiconductor device will be described below.

Synthesis example 1
30 g of 2-hydroxyethyl acrylate was dissolved in 120 g of ethyl lactate, and nitrogen was passed through the reaction solution for 30 minutes, and then the temperature was raised to 70 ° C. While maintaining the reaction solution at 70 ° C., 0.3 g of azobisisobutyronitrile was added and stirred at 70 ° C. for 24 hours under a nitrogen atmosphere to obtain a 20% by mass solution of poly (2-hydroxyethyl) acrylate. It was.
The obtained polymer was subjected to GPC analysis using a GPC (RI8020, SD8022, CO8020, AS8020, DP8020) apparatus manufactured by Tosoh Corporation. The analysis was carried out by flowing 10 μl of a 0.05% by mass DMF solution of the obtained polymer through the apparatus at a flow rate of 0.6 ml / min for 30 minutes and then measuring the elution time of the sample to be detected by RI. Also, the trade name Shodex Asahipak GF1G7B was used as the guard column, the trade names Shodex Asahipak GF710HQ, GF510HQ and GF310HQ were used as the columns, and the column temperature was set to 40 ° C.
As a result, the weight average molecular weight of the obtained polymer was 9,800 (standard polystyrene conversion).

Example 1
To 20 g of the solution containing poly (2-hydroxyethyl) acrylate obtained in Synthesis Example 1, 0.92 g of tetramethoxymethyl glycoluril, 0.0046 g of pyridinium-p-toluenesulfonic acid, 9.50 g of propylene glycol monomethyl ether, and lactic acid 6.18 g of ethyl was added and filtered using a polyethylene microfilter having a pore size of 0.05 μm. Thereafter, the mixed solution was diluted 10-fold with ethyl lactate, and 1 × 10 ⁻ of N, N′-bis (2,6-dimethylphenyl) perylene-3,4,9,10-tetracarboxylic acid diimide as a fluorescent molecule. ^An equal amount of ⁹ mol / l ethyl lactate solution was mixed to prepare a solution of a cured film forming composition.

Example 2
A diffusion coefficient measuring apparatus according to Embodiment 2 of the present invention is shown in FIG. 75 μl of the cured film forming composition solution prepared in Example 1 above was dropped onto a clean glass substrate (thickness 0.17 mm) and spin-cast at a rotational speed of 2000 rpm to obtain a thin film sample 1 having a thickness of 58 nm. . The thin film sample 1 (9) was placed on the electric stage (8) of the microscope shown in FIG. A high refractive index oil is applied between the thin film sample 1 (9) and the objective lens (7) and is filled with the oil. Using a continuous wave laser beam (argon ion laser (1)) with a wavelength of 488 nm as an excitation light source, the thin film sample 1 (9) is irradiated in the range of intensity of 1 to 30 mW, and the back-illuminated type EMCCD camera (11) shown in FIG. The exposure time is appropriately changed in the range of 10 ms (milliseconds) to 10 s (seconds), and the fluorescent molecule N, N′-bis (2,6-dimethylphenyl) perylene-3,4, in the thin film sample 1 (9) is selected. A monomolecular fluorescence image (moving image) of 9,10-tetracarboxylic acid diimide was obtained in the range of several seconds to several tens of minutes. An example of the obtained fluorescence image is shown in FIG. Since fluorescent molecules diffuse two-dimensionally in the film, the fluorescent luminescent spot is not out of focus with translational diffusion.

  The two-dimensional signal intensity distribution of the fluorescent bright spots in the obtained image was fitted with a two-dimensional Gaussian function, and the barycentric coordinate of the two-dimensional Gaussian was determined as the position coordinate of the fluorescent molecule. The position coordinates of the fluorescent molecules displaced with time were sequentially determined for each molecule. FIG. 3 shows an example of a locus of molecular displacement. Using the position information of each molecule obtained by the above procedure, the mean square displacement (MSD) was obtained from the following formula (1).

In the above formula (1), x _i and y _i are the coordinates of the numerator in the i-th frame, n is a positive integer indicating how many squares to calculate the square displacement, and N represents the total number of frames.

  Thereafter, the diffusion coefficient of each molecule in the thin film sample 1 was determined by a two-dimensional diffusion equation (formula (2)).

  In the above formula (2), D is a translational diffusion coefficient, and t is time (seconds).

As a result of the above operation, the diffusion coefficient of the fluorescent molecule N, N′-bis (2,6-dimethylphenyl) perylene-3,4,9,10-tetracarboxylic acid diimide in the thin film sample 1 is shown in FIG. In this case, it was determined to be 0.0057135 μm ² / s.

As described above, as a result of obtaining the diffusion coefficient of the fluorescent molecule from the change in the position of the fluorescent molecule obtained using the measuring apparatus and the calculation formulas shown in the equations (1) to (2), It was confirmed that the diffusion coefficient can be obtained with extremely high accuracy, and that the structure and handling of the diffusion coefficient measurement system is very simple.
That is, the measurement method of the present invention includes a low molecular weight substance in each film by measuring the diffusion coefficient by including fluorescent molecules in various cured films as a measurement target, and comparing the diffusion in each film relative to each other. The ease of movement can be compared.

  The diffusion coefficient measurement method according to the present invention includes a cured film containing a fluorescent molecule as described above, and a diffusion coefficient obtained based on a change in position of the fluorescent molecule in the sample containing the fluorescent molecule and a diffusion equation. The measurement method, which is the film formation method that is actually used in the semiconductor manufacturing process, and because it can be measured with a thin film, diffusion of the fluorescent molecules in the photoresist and the resist underlayer film at the interface between the photoresist and the resist underlayer film The phenomenon can be studied and applied to the development of a photoresist and a resist underlayer film for controlling the photoresist shape.

FIG. 1 shows a diffusion coefficient measuring apparatus. FIG. 2 is a diagram showing an example of a fluorescent image obtained in Example 2. FIG. 3 is a diagram showing a locus of positional displacement of the fluorescent molecule obtained from the fluorescent image obtained in Example 2.

Explanation of symbols

(1) Argon ion laser (wavelength λ = 488 nm)
(2) Laser line filter (3) Objective lens (20x magnification)
(4) Optical fiber (5) Objective lens (10x magnification)
(6) Dichroic mirror (7) Objective lens (magnification 100 times, numerical aperture NA = 1.35)
(8) Electric stage (9) Thin film sample (10) Edge filter for Raman spectroscopy (11) Back-illuminated EMCCD camera (12) Computer

Claims (13)

A method for identifying a diffusion process of a low-molecular substance in a cured material by a single fluorescent molecular detection method combining an optical microscope and a CCD camera,
The diffusion coefficient during laser excited fluorescent molecules rotate or translate in the cured material, a method Ru determined based on the change with time of the position of the bright spot with fluorescent molecules in the curable material and the diffusion equation, and
The time-dependent change in the position of the bright spot is determined by a high-speed image analysis program according to two-dimensional Gaussian fitting when acquiring the position information of the bright spot,
Diffusion coefficient measurement method. For the excitation of the fluorescent molecules, a continuous wave Ar ion laser, He-Ne laser or semiconductor laser is used in the ultraviolet to visible range,
A step of separating excitation light and fluorescence by transmitting the laser light through a high-precision laser line filter having a transmission bandwidth of 4 nm or less and a wavelength discriminating filter, and the CCD element from minus 70 ° C. to minus 200 ° C. A CCD camera equipped with a Peltier element cooled back-illuminated CCD detector capable of cooling and removing thermal noise with high accuracy is used.
The method for measuring a diffusion coefficient according to claim 1. By magnifying a fluorescent image using a 2 to 10 times relay lens, a single molecule fluorescent luminescent spot is detected across a plurality of adjacent CCD elements,
The corresponding observation range of the CCD 1 element provided in the CCD detector is set to 1 to 100 nm,
The method for measuring a diffusion coefficient according to claim 2. The method of measuring a diffusion coefficient according to any one of claims 1 to 3 , wherein the fluorescent molecule is a molecule that dissolves in a sample solvent and emits fluorescence in a wavelength range of 150 to 800 nm. The method for measuring a diffusion coefficient according to claim 4 , wherein the fluorescent molecule is a perylene compound, a terylene compound, a carbocyanine compound, or a phenoxazine compound. The fluorescent molecule is N, N'-bis (2,6-dimethylphenyl) perylene-3,4,9,10-tetracarboxylic acid diimide, N- (2,6-diisopropylphenyl) -N '-(n- Octyl) -terylene-3,4,11,12-tetracarboxylic acid diimide, NN′-bis (2,6-diisopropylphenyl) terylene-3,4,11,12-tetracarboxylic acid diimide, 1,1 '- dioctadecyl-3,3,3', 3'-tetramethyl-indocarbocyanine perchlorate, or 9- (diethylamino) -5H- benzo (a) phenoxazine-5-one, according to claim 5 The measuring method of the diffusion coefficient as described in 2. The method for measuring a diffusion coefficient according to any one of claims 1 to 6 , wherein the curable material is a material obtained by thermosetting a thermosetting film forming composition. The said thermosetting film formation composition is a measuring method of the diffusion coefficient of Claim 7 containing the thermosetting monomer and / or thermosetting resin which have at least 1 crosslinking reaction group. The method for measuring a diffusion coefficient according to claim 8 , wherein the thermosetting film-forming composition further contains a crosslinking agent and a solvent. The method for measuring a diffusion coefficient according to any one of claims 1 to 6 , wherein the curable material is a material obtained by photocuring a photocurable film-forming composition. The method for measuring a diffusion coefficient according to claim 10 , wherein the photocured film-forming composition contains a photocurable monomer having at least one photocrosslinking reaction group or a photocurable resin. The method for measuring a diffusion coefficient according to claim 11 , wherein the photocured film-forming composition further contains a photoreactive initiator and a solvent. Wherein the curing material, a photoresist film used in lithography process for manufacturing a semiconductor device, or is formed from a cured film forming composition for use in a photoresist underlayer film, either one of claims 1 to 12 1 A method for measuring the diffusion coefficient according to the item.