Methods for preventing the collapse of three-dimensional structures

Abstract

The present invention provides a method for preventing the collapse of a three-dimensional structure, which can effectively hydrophobize the surface of a three-dimensional structure on a substrate regardless of the type of material of the substrate or the type of material of the three-dimensional structure, and as a result, can effectively prevent the collapse of the three-dimensional structure on the substrate; a surface treatment liquid that is preferably used for the surface treatment of the three-dimensional structure in the collapse prevention method; a method for producing the same; and a substrate having a three-dimensional structure with a silane condensate, which is a component of the surface treatment liquid, attached to or bonded to its surface. [Solution] In a method for preventing the collapse of a three-dimensional structure, which includes preparing a substrate having a three-dimensional structure patterned on its surface, and contacting the surface of the three-dimensional structure with a surface treatment liquid, the surface treatment liquid used includes a silane condensate (A), which is a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound including a trifunctional silane compound (A1) having a specific structure, and an organic solvent (S).

Description

[Technical Field]

[0001] The present invention relates to a method for preventing the collapse of a three-dimensional structure on a substrate, a surface treatment liquid suitable for use in the collapse prevention method for the surface treatment of a three-dimensional structure, a method for producing the same, and a substrate having a three-dimensional structure on its surface to which a silane condensate, which is a component of the surface treatment liquid, is attached or bonded. [Background technology]

[0002] In recent years, the trend toward higher integration and miniaturization of semiconductor devices has intensified, resulting in advances in miniaturization and higher aspect ratios of resin patterns, which serve as etching masks when etching substrates, and inorganic patterns fabricated by etching processes. However, at the same time, problems have arisen with the collapse of three-dimensional structures, such as resin patterns and inorganic patterns, on substrates. The collapse of three-dimensional structures on substrates occurs when multiple resin or inorganic patterns are formed in parallel on a substrate, resulting in adjacent patterns leaning against each other and, in some cases, causing the patterns to break or peel off from their bases. Such collapse of three-dimensional structures leads to reduced product yield and reliability.

[0003] It is known that collapse of the three-dimensional structure is likely to occur due to the surface tension of the cleaning solution when it dries during the cleaning process after the patterned three-dimensional structure is formed. When the cleaning solution is removed during the drying process, stress based on the surface tension of the cleaning solution acts between the patterns, causing the pattern to collapse.

[0004] Therefore, it has been proposed to prevent the collapse of three-dimensional structures by hydrophobizing (silylating) the surface of a resin pattern or an inorganic pattern using a surface treatment liquid containing a silylating agent such as N,N-dimethylaminotrimethylsilane (TMSDMA) or hexamethyldisilazane (HMDS) and a solvent (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-129932 Summary of the Invention [Problem to be solved by the invention]

[0006] In the method using a surface treatment liquid containing a silylating agent as described in Patent Document 1, depending on the type of material of the substrate and the type of material of the three-dimensional structure, the surface may not be hydrophobized well, and the collapse of the three-dimensional structure on the substrate may not be suppressed to the desired extent.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a method for preventing the collapse of a three-dimensional structure, which can effectively hydrophobize the surface of a three-dimensional structure on a substrate regardless of the type of material of the substrate or the type of material of the three-dimensional structure, and as a result, can effectively prevent the collapse of the three-dimensional structure on the substrate, a surface treatment liquid that is preferably used for surface treatment of a three-dimensional structure in the collapse prevention method, a method for producing the same, and a substrate having a three-dimensional structure with a silane condensate, which is a component of the surface treatment liquid, attached to or bonded to its surface. [Means for solving the problem]

[0008] The present inventors have discovered that the above-mentioned problems can be solved by using a surface treatment solution containing a silane condensate (A), which is a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound including a trifunctional silane compound (A1) having a specific structure, and an organic solvent (S) in a method for preventing the collapse of a three-dimensional structure, the method comprising preparing a substrate having a patterned three-dimensional structure on its surface and contacting the surface of the three-dimensional structure with a surface treatment solution, and have completed the present invention. Specifically, the present invention provides the following.

[0009] A first aspect of the present invention includes providing a substrate having a three-dimensional structure patterned on its surface; bringing the surface of the three-dimensional structure into contact with a surface treatment liquid; the surface treatment liquid contains a silane condensate (A) and an organic solvent (S), The silane condensate (A) is represented by the following formula (a1): SiR a1 (R a2 )3···(a1) (In formula (a1), R a1 is a hydrocarbon group having 1 to 20 carbon atoms, and R a2 is a group that generates a silanol group upon hydrolysis, and three R a2 may be the same or different.) a condensation product obtained by hydrolysis and condensation of a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the following formula: In the method for preventing the collapse of a three-dimensional structure, the concentration of the silane condensate (A) in the surface treatment liquid is 0.00005% by mass or more and 40% by mass or less.

[0010] A second aspect of the present invention is a method for producing a surface treatment liquid to be brought into contact with a three-dimensional structure patterned on a substrate, the method comprising: the surface treatment liquid contains a silane condensate (A) and an organic solvent (S), the concentration of the silane condensate (A) in the surface treatment liquid is 0.00005% by mass or more and 40% by mass or less, The following formula (a1): SiR a1 (R a2 )3···(a1) (In formula (a1), R a1 is a hydrocarbon group having 1 to 20 carbon atoms, and R a2 is a group that generates a silanol group upon hydrolysis, and three R a2 may be the same or different.) The method for producing a surface treatment liquid includes hydrolyzing and condensing a hydrolyzable silane compound including a trifunctional silane compound (A1) represented by the following formula to produce a silane condensate (A).

[0011] A third aspect of the present invention is a surface treatment liquid to be brought into contact with a three-dimensional structure patterned on a substrate, the surface treatment liquid comprising: the surface treatment liquid contains a silane condensate (A) and an organic solvent (S), The silane condensate (A) is represented by the following formula (a1): SiR a1 (R a2 )3···(a1) (In formula (a1), R a1 is a hydrocarbon group having 1 to 20 carbon atoms, and R a2 is a group that generates a silanol group upon hydrolysis, and three R a2 may be the same or different.) a condensation product obtained by hydrolysis and condensation of a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the following formula: The surface treatment liquid has a concentration of the silane condensate (A) of 0.00005% by mass or more and 40% by mass or less.

[0012] A fourth aspect of the present invention is a substrate having a patterned three-dimensional structure on its surface, The surface of the three-dimensional structure is provided with the following formula (a1): SiR a1 (R a2 )3···(a1) (In formula (a1), R a1 is a hydrocarbon group having 1 to 20 carbon atoms, and R a2 is a group that generates a silanol group upon hydrolysis, and three R a2 may be the same or different.) The substrate has a silane condensate (A) attached or bonded thereto, the silane condensate (A) being a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the following formula:

[0013] A fifth aspect of the present invention provides a method for manufacturing a substrate having a three-dimensional structure patterned on a surface thereof; bringing the surface of the three-dimensional structure into contact with a surface treatment liquid; the surface treatment liquid contains a silane condensate (A) and an organic solvent (S); The silane condensate (A) is represented by the following formula (a1): SiR a1 (R a2 )3···(a1) (In formula (a1), R a1 is a hydrocarbon group having 1 to 20 carbon atoms, and R a2 is a group that generates a silanol group upon hydrolysis, and three R a2 may be the same or different.) a condensation product obtained by hydrolysis and condensation of a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the following formula: The method for treating the surface of a three-dimensional structure on a substrate having a three-dimensional structure patterned on the surface thereof comprises the step of: the concentration of the silane condensate (A) in the surface treatment liquid is 0.00005% by mass or more and 40% by mass or less. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a method for preventing the collapse of a three-dimensional structure, which can effectively hydrophobize the surface of a three-dimensional structure on a substrate regardless of the type of material of the substrate or the type of material of the three-dimensional structure, and as a result, can effectively prevent the collapse of the three-dimensional structure on the substrate, a surface treatment liquid that is preferably used for the surface treatment of the three-dimensional structure in the collapse prevention method, a method for producing the same, and a substrate having a three-dimensional structure with a silane condensate, which is a component of the surface treatment liquid, attached to or bonded to its surface. [Brief explanation of the drawings]

[0015] [Figure 1] 1 shows a GPC chromatogram of n-octyltrimethoxysilane, a reaction raw material, and a GPC chromatogram of the reaction mixture in Example 13. [Figure 2] In Example 13, these show a GPC chromatogram of n-octyltrimethoxysilane, which is a reaction raw material, a GPC chromatogram of the reaction mixture, and a chromatogram of a solution containing the reaction product diluted with propylene glycol monomethyl ether acetate (PGMEA) after completion of the reaction. [Figure 3] 1 is a chromatogram of a silane condensate (oligomer) contained in a reaction mixture one day after mixing of raw materials in Example 13. [Figure 4] 1 is a chromatogram of a silane condensate (oligomer) contained in a reaction mixture 5 days after mixing of raw materials in Example 13. DETAILED DESCRIPTION OF THE INVENTION

[0016] <Collapse prevention methods> The collapse suppression method suppresses collapse of a three-dimensional structure on a substrate having a three-dimensional structure patterned on its surface. The method of preventing collapse is providing a substrate having a patterned three-dimensional structure on its surface; and bringing the surface of the three-dimensional structure into contact with a surface treatment liquid. Hereinafter, preparing a substrate having a patterned three-dimensional structure on its surface is also referred to as a “preparation step.” Contacting the surface of the three-dimensional structure with a surface treatment solution is also referred to as a “surface treatment step.”

[0017] The surface treatment liquid contains a silane condensate (A) and an organic solvent (S). The silane condensate (A) is represented by the following formula (a1): SiR a1 (R a2 )3···(a1) (In formula (a1), R a1 is a hydrocarbon group having 1 to 20 carbon atoms, and R a2 is a group that generates a silanol group upon hydrolysis, and three R a2 may be the same or different.) The compound is a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the following formula: The concentration of the silane condensate (A) in the surface treatment liquid is 0.00005% by mass or more and 40% by mass or less.

[0018] In a method for preventing collapse of a three-dimensional structure, which includes preparing a substrate having a three-dimensional structure patterned on its surface and contacting the surface of the three-dimensional structure with a surface treatment liquid, the surface treatment liquid is used, which includes a silane condensate (A), which is a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound including a trifunctional silane compound (A1) represented by the above formula (a1), and an organic solvent (S).This makes it possible to effectively hydrophobize the surface of the three-dimensional structure on the substrate regardless of the type of material of the substrate or the type of material of the three-dimensional structure, and as a result, effectively prevent the three-dimensional structure on the substrate from collapsing.

[0019] As mentioned above, it is known that collapse of a three-dimensional structure on a substrate occurs due to the surface tension of the cleaning solution when the cleaning solution dries during the cleaning process after the formation of a patterned three-dimensional structure. In particular, the surface tension of the water contained in the cleaning solution or the moisture remaining in the environment surrounding the three-dimensional structure has a large effect. Even if a liquid with low surface tension is used as a rinse solution, when the rinse solution is removed during the drying process, stress due to the surface tension of the moisture remaining between the three-dimensional structures acts, causing the three-dimensional structure to collapse.

[0020] Here, the force F acting between the three-dimensional structures during the drying process after rinsing is expressed by the following formula (I): where γ represents the surface tension of the liquid entering between the three-dimensional structures, θ represents the contact angle of the liquid entering between the three-dimensional structures, A represents the aspect ratio of the three-dimensional structures, and D represents the distance between the side walls of the three-dimensional structures. The liquid entering between the three-dimensional structures is, for example, a rinse liquid, and if water enters between the three-dimensional structures because the rinse liquid and water are not miscible, the liquid will be water. F=2γ cosθ A / D (I)

[0021] Therefore, if the surfaces of the substrate and the three-dimensional structure can be made hydrophobic and the contact angle of the liquid, such as the rinse solution, that enters between the three-dimensional structures can be increased (cosθ can be reduced), the force acting between the three-dimensional structures during the drying process after rinsing can be reduced, and the three-dimensional structures can be prevented from collapsing. Therefore, in a substrate having a patterned three-dimensional structure, the collapse of the three-dimensional structure can be effectively prevented by hydrophobizing the surfaces of the three-dimensional structure and the substrate through surface treatment with the above-mentioned surface treatment liquid.

[0022] <Preparation process> In the preparation step, a substrate having a three-dimensional structure patterned on its surface is prepared. There are no particular limitations on the shape of the substrate, the material of the substrate, the shape of the three-dimensional structure, the pattern shape of the three-dimensional structure, the arrangement of the three-dimensional structure on the substrate, and the material of the three-dimensional structure.

[0023] The shape of the substrate is not particularly limited as long as it has a patterned three-dimensional structure on its surface. The three-dimensional structure may be formed on the surface of the substrate using a material different from or the same as the material of the substrate. Alternatively, the three-dimensional structure may be formed integrally with the substrate by providing irregularities on the surface of the substrate using a method such as etching to selectively remove the surface layer of the substrate.

[0024] The material of the substrate is not particularly limited. The material of the substrate may be an organic material or an inorganic material. Examples of organic materials include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycarbonate, and acrylic resin. Examples of inorganic materials include silicon, silicon oxide, silicon nitride, tantalum, tantalum nitride, tungsten, titanium oxide, titanium nitride, aluminum oxide, and carbon.

[0025] The material of the three-dimensional structure may be either an organic material or an inorganic material. Suitable examples of organic materials for the three-dimensional structure include various resins exemplified as materials for the substrate, and various resins or resin compositions that can be formed using known resist compositions. Suitable examples of inorganic materials for the three-dimensional structure are the same as the suitable examples of inorganic materials for the substrate.

[0026] The shape of the substrate is not particularly limited, and is typically preferably a flat plate shape having a circular or approximately circular main surface, or a flat plate shape having a polygonal main surface such as a square or rectangle.

[0027] The pattern shape of the three-dimensional structure is not particularly limited. Typical pattern shapes of the three-dimensional structure include a line-and-space pattern consisting of line portions having a rectangular or approximately rectangular cross section and space portions having a rectangular or approximately rectangular cross section located between two line portions, and a dot pattern consisting of cylindrical or prismatic dot portions such as square prisms. Note that multiple types of three-dimensional structure patterns may exist on the same substrate.

[0028] The size of the three-dimensional structures is not particularly limited. Since the effect of suppressing the collapse of the three-dimensional structures is significant, the shortest distance between the three-dimensional structures constituting the pattern is preferably 50 nm or less, more preferably 35 nm or less, and preferably 25 nm or less. The lower limit of the shortest distance between the three-dimensional structures is not particularly limited, but is, for example, 5 nm or more. The shortest distance between three-dimensional structures corresponds to D in the above formula (I). The smaller D, the greater the force F acting between the three-dimensional structures. Therefore, the shorter the shortest distance between the three-dimensional structures, the more effective the above-mentioned method for suppressing the collapse of three-dimensional structures. The distance between the tops of the three-dimensional structures is defined as the distance between the three-dimensional structures. When adjacent three-dimensional structures have different heights, the distance between the top of the shorter three-dimensional structure and the same position as the top of the shorter three-dimensional structure in the height direction of the taller three-dimensional structure is defined as the distance between the three-dimensional structures. The height direction of the three-dimensional structure is usually perpendicular to the surface direction of the substrate.

[0029] When the three-dimensional structure is a line portion of a line-and-space pattern, the width of the line portion is preferably 1 nm to 50 nm, more preferably 2 nm to 35 nm, and even more preferably 5 nm to 25 nm. The width of the line portion is the length at the top of the line portion in the direction parallel to the surface of the substrate. When the three-dimensional structure is a dot pattern, the diameter of the dot is preferably 1 nm to 50 nm, more preferably 5 nm to 30 nm. The diameter of the dot is the length of the part of the extended line that overlaps with the top of the dot when the line showing the shortest distance between two adjacent dots is extended. For example, if the dot is cylindrical, the diameter of the dot is the diameter of the top circle. If the dot is a quadrangular prism with a square top and multiple dots are arranged so that the sides of the square top are parallel, the diameter of the dot is the length of one side of the square top.

[0030] The aspect ratio of the three-dimensional structure is preferably 4 or more, 5 or more, 6 or more, 8 or more, 10 or more, 12 or more, 15 or more, or 20 or more. The higher the aspect ratio, the more preferable. In reality, the upper limit of the aspect ratio is 100 or less, and preferably 50 or less. The aspect ratio corresponds to A in the above formula (I). The larger A, the greater the force F acting between the three-dimensional structures. Therefore, the larger the aspect ratio of the three-dimensional structure, the more effective the above-mentioned method for suppressing the collapse of the three-dimensional structure. When the three-dimensional structure is a line portion of a line and space pattern, the aspect ratio of the three-dimensional structure is the value of the height of the line portion divided by the width of the line portion. When the three-dimensional structure is a dot portion of a dot pattern, the aspect ratio of the three-dimensional structure is the value of the height of the dot portion divided by the diameter of the dot portion.

[0031] The substrate having the three-dimensional structure patterned on its surface as described above is subjected to a surface treatment step.

[0032] <Surface treatment process> In the surface treatment step, the surface of the three-dimensional structure on the substrate is brought into contact with a surface treatment liquid. The method for bringing the surface treatment liquid into contact with the three-dimensional structure is not particularly limited. As the method for bringing the surface treatment liquid into contact with the three-dimensional structure, a conventionally known method can be used without particular limitation. For example, there is a method for bringing the surface treatment liquid into contact with the three-dimensional structure on the substrate by a spray method, a spin coating method, a dip coating method, a roll coating method, or the like.

[0033] The treatment time for contacting the three-dimensional structure with the surface treatment solution is not particularly limited as long as the desired collapse suppression effect is obtained. For example, the treatment time is preferably from 1 second to 30 minutes, more preferably from 5 seconds to 10 minutes, and even more preferably from 10 seconds to 5 minutes. After the surface treatment, the water contact angle on the surface of the three-dimensional structure is preferably 70° or more, more preferably 75° or more, and even more preferably 80° or more. The higher the water contact angle, the better. There is no particular upper limit within the measurable range, but it may be, for example, 130° or less, or about 125° or less.

[0034] The temperature of the surface treatment solution during the surface treatment is not particularly limited as long as the desired collapse-inhibiting effect can be obtained. The temperature of the surface treatment solution during the surface treatment is, for example, preferably 0°C or higher and 60°C or lower, more preferably 5°C or higher and 50°C or lower, and even more preferably 10°C or higher and 40°C or lower, because this makes it difficult for the composition of the surface treatment solution to change due to evaporation or decomposition of the organic solvent (S) and makes it easier to stably obtain the desired collapse-inhibiting effect.

[0035] After the surface treatment with the surface treatment liquid, if the organic solvent (S) contained in the surface treatment liquid remains on the surface of the substrate, it is preferable to remove such residue. The method for removing the residue is not particularly limited, and examples thereof include a method of blowing a gas such as nitrogen or dry air onto the surface of the substrate, a method of heating the substrate to an appropriate temperature depending on the boiling point of the solvent to be removed, and a method of cleaning with a conventionally known cleaning liquid used in cleaning treatment (for example, water, isopropyl alcohol, activator rinse, SPM, APM, etc.). From the viewpoint of throughput, it is preferable that the surface treatment and the cleaning treatment for removing residual materials are performed consecutively. For this reason, it is preferable to select an organic solvent (S) that has excellent exchangeability with the cleaning solution as the organic solvent contained in the surface treatment solution.

[0036] [Surface treatment liquid] The surface treatment liquid used for the above surface treatment contains a silane condensate (A) and an organic solvent (S). The silane condensate (A) is a silane condensate represented by the following formula (a1): SiR a1 (R a2 )3···(a1) (In formula (a1), R a1 is a hydrocarbon group having 1 to 20 carbon atoms, and R a2 is a group that generates a silanol group upon hydrolysis, and three R a2 may be the same or different.) The compound is a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the following formula: The silane condensate (A) is obtained by hydrolysis and condensation of a hydrolyzable silane compound having a group that generates a silanol group upon hydrolysis. Such a silane condensate has a silanol group. The silane condensate (A) having a silanol group adheres well to various materials and effectively hydrophobizes the surfaces of the substrate and the three-dimensional structure, regardless of the material of the substrate or the three-dimensional structure. As a result, an excellent effect of suppressing the collapse of the three-dimensional structure is obtained. Therefore, the surface treatment liquid is useful as a surface treatment liquid for hydrophobizing various materials, and is particularly useful as a surface treatment liquid for hydrophobizing the surface of a three-dimensional structure patterned on a substrate.

[0037] In formula (a1), R a1 The hydrocarbon group represented by R may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. a1The hydrocarbon group as may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a combination of an aliphatic hydrocarbon group and an aromatic hydrocarbon group. R a1 When the hydrocarbon group as the alkyl group contains an aliphatic hydrocarbon group, the aliphatic hydrocarbon group may be linear, branched, or cyclic.

[0038] R a1 Specific preferred examples of the hydrocarbon group as include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a pentan-3-yl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, and an n-octadecyl group. alkyl groups such as a cyclopropyl group, an n-nonadecyl group, and an n-icosyl group; cycloalkyl groups such as a cyclopropyl group, an n-butyl group, an n-cyclopentyl group, an n-cyclohexyl group, an n-cycloheptyl group, an n-cyclooctyl group, an n-cyclononyl group, and an n-cyclohexyl group; aromatic hydrocarbon groups such as a phenyl group, a naphthalen-1-yl group, a naphthalen-2-yl group, a 4-phenylphenyl group, a 3-phenylphenyl group, and a 2-phenylphenyl group; and aralkyl groups such as a benzyl group, a phenethyl group, a 3-phenylpropyl group, a naphthalen-1-ylmethyl group, and a naphthalen-2-ylmethyl group.

[0039] R a1 As the hydrocarbon group, from the viewpoint of achieving both ease of attachment or bonding of the silane condensate (A) to a substrate or a three-dimensional structure due to a high degree of steric freedom and good hydrophobicity, an alkyl group having 1 to 20 carbon atoms is preferred, an alkyl group having 1 to 18 carbon atoms is more preferred, and an alkyl group having 1 to 12 carbon atoms is even more preferred.

[0040] In formula (a1), Ra2 is a group that generates a silanol group upon hydrolysis. In the trifunctional silane compound (A1) represented by formula (a1), three R a2 may be the same or different from each other. Examples of groups that generate silanol groups upon hydrolysis include alkoxy groups having from 1 to 12 carbon atoms, alkoxyalkoxy groups having from 2 to 12 carbon atoms, halogen atoms, amino groups, and acyloxy groups having from 1 to 12 carbon atoms. Of these groups, alkoxy groups having from 1 to 12 carbon atoms are preferred, alkoxy groups having from 1 to 6 carbon atoms are more preferred, and alkoxy groups having from 1 to 4 carbon atoms are particularly preferred, due to their favorable hydrolysis reactivity.

[0041] Specific preferred examples of groups that generate silanol groups upon hydrolysis include alkoxy groups such as a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, and an n-butyloxy group; alkoxyalkoxy groups such as a methoxymethoxy group, an ethoxymethoxy group, a 2-methoxyethoxy group, and a 2-ethoxyethoxy group; halogen atoms such as a chlorine atom and a bromine atom; and acyloxy groups such as an acetoxy group and a propionyloxy group.

[0042] In terms of the ease of obtaining silane compounds and the ease of obtaining a surface treatment liquid having an excellent collapse suppression effect, the trifunctional silane compound (A1) represented by formula (a1) described above is preferably R a1 is an alkyl group having 1 to 12 carbon atoms, and R a2 is preferably an alkoxy group having 1 to 4 carbon atoms.

[0043] Specific preferred examples of the trifunctional silane compound (A1) represented by formula (a1) include methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isopropyltrimethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, sec-butyltrimethoxysilane, tert-butyltrimethoxysilane, n-pentyltrimethoxysilane, neopentyltrimethoxysilane, isopentyltrimethoxysilane, sec-pentyltrimethoxysilane, and tert-pentyltrimethoxysilane. Trimethoxysilane, pentan-3-yltrimethoxysilane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, 2-ethylhexyltrimethoxysilane, n-nonyltrimethoxysilane, n-decyltrimethoxysilane, n-undecyltrimethoxysilane, n-dodecyltrimethoxysilane, n-tridecyltrimethoxysilane, n-tetradecyltrimethoxysilane, n-pentadecyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-heptadecyltrimethoxysilane alkyltrimethoxysilanes such as methoxysilane, n-octadecyltrimethoxysilane, n-nonadecyltrimethoxysilane, and n-icosyltrimethoxysilane; cycloalkyltrimethoxysilanes such as cyclopropyltrimethoxysilane, cyclobutyltrimethoxysilane, cyclopentyltrimethoxysilane, cyclohexyltrimethoxysilane, cycloheptyltrimethoxysilane, cyclooctyltrimethoxysilane, cyclononyltrimethoxysilane, and cyclohexyltrimethoxysilane; aryltrimethoxysilanes such as phenyltrimethoxysilane, naphthalen-1-yltrimethoxysilane, naphthalen-2-yltrimethoxysilane, 4-phenylphenyltrimethoxysilane, 3-phenylphenyltrimethoxysilane, and 2-phenylphenyltrimethoxysilane; aralkyltrimethoxysilanes such as benzyltrimethoxysilane, phenethyltrimethoxysilane, 3-phenylpropyltrimethoxysilane, naphthalen-1-ylmethyltrimethoxysilane, and naphthalen-2-ylmethyltrimethoxysilane;Methyltriethoxysilane, ethyltriethoxysilane, n-propyltriethoxysilane, isopropyltriethoxysilane, n-butyltriethoxysilane, isobutyltriethoxysilane, sec-butyltriethoxysilane, tert-butyltriethoxysilane, n-pentyltriethoxysilane, neopentyltriethoxysilane, isopentyltriethoxysilane, sec-pentyltriethoxysilane, tert-pentyltriethoxysilane, pentan-3-yltriethoxysilane, n-Hexyltriethoxysilane, n-heptyltriethoxysilane, n-octyltriethoxysilane, 2-ethylhexyltriethoxysilane, n-nonyltriethoxysilane, n-decyltriethoxysilane, n-undecyltriethoxysilane, n-dodecyl group, n-tridecyltriethoxysilane, n-tetradecyltriethoxysilane, n-pentadecyltriethoxysilane, n-hexadecyltriethoxysilane, n-heptadecyltriethoxysilane, n-octadecyltriethoxysilane alkyltriethoxysilanes such as n-nonadecyltriethoxysilane and n-icosyltriethoxysilane; cycloalkyltriethoxysilanes such as cyclopropyltriethoxysilane, cyclobutyltriethoxysilane, cyclopentyltriethoxysilane, cyclohexyltriethoxysilane, cycloheptyltriethoxysilane, cyclooctyltriethoxysilane, cyclononyltriethoxysilane, and cyclohexyltriethoxysilane; phenyltriethoxysilane, naphthalene-1-yltriethoxysilane, aryltriethoxysilanes such as aryltriethoxysilane, naphthalen-2-yltriethoxysilane, 4-phenylphenyltriethoxysilane, 3-phenylphenyltriethoxysilane, and 2-phenylphenyltriethoxysilane; aralkyltriethoxysilanes such as benzyltriethoxysilane, phenethyltriethoxysilane, 3-phenylpropyltriethoxysilane, naphthalen-1-ylmethyltriethoxysilane, and naphthalen-2-ylmethyltriethoxysilane;

[0044] The content of the trifunctional silane compound (A1) represented by formula (a1) in the hydrolyzable silane compound to be subjected to hydrolysis condensation is not particularly limited as long as the desired effect can be obtained. The content of the trifunctional silane compound (A1) represented by formula (a1) in the hydrolyzable silane compound to be subjected to hydrolysis condensation is preferably 50 mass% or more, more preferably 70 mass% or more, even more preferably 80 mass% or more, particularly preferably 90 mass% or more, and most preferably 100 mass% based on the total mass of the hydrolyzable silane compound.

[0045] The hydrolyzable silane compound may contain at least one compound selected from a bifunctional silane compound (A2) and a monofunctional silane compound (A3) as a compound capable of hydrolytic condensation with the trifunctional silane compound (A1) represented by formula (a1).

[0046] The bifunctional silane compound (A2) is preferably a compound represented by the following formula (a2). Si(R a1 )2(R a2 )2···(a2) (In formula (a2), R a1 is a hydrocarbon group having 1 to 20 carbon atoms, and R a2 is a group that generates a silanol group upon hydrolysis, and two R a1 may be the same or different, and two R a2 may be the same or different.)

[0047] In formula (a2), R a1 hydrocarbon groups as R a2 The group that generates a silanol group upon hydrolysis as described above is as described for formula (a1).

[0048] Specific preferred examples of the bifunctional silane compound (A2) include dimethyldimethoxysilane, diethyldimethoxysilane, di-n-propyldimethoxysilane, diisopropyldimethoxysilane, di-n-butyldimethoxysilane, diisobutyldimethoxysilane, di-sec-butyldimethoxysilane, di-tert-butyldimethoxysilane, di-n-pentyldimethoxysilane, dineopentyldimethoxysilane, diisopentyldimethoxysilane, di-sec-pentyldimethoxysilane, di-tert-pentyldimethoxysilane, di(pentan-3-yl)dimethoxysilane, di-n-hexyldimethoxysilane, di-n dialkyldimethoxysilanes such as -heptyldimethoxysilane, di-n-octyldimethoxysilane, di-2-ethylhexyldimethoxysilane, di-n-nonyldimethoxysilane, di-n-decyldimethoxysilane, di-n-undecyldimethoxysilane, di-n-dodecyldimethoxysilane, di-n-tridecyldimethoxysilane, di-n-tetradecyldimethoxysilane, di-n-pentadecyldimethoxysilane, di-n-hexadecyldimethoxysilane, di-n-heptadecyldimethoxysilane, di-n-octadecyldimethoxysilane, di-n-nonadecyldimethoxysilane, and di-n-icosyldimethoxysilane;Dimethyldiethoxysilane, diethyldiethoxysilane, di-n-propyldiethoxysilane, diisopropyldiethoxysilane, di-n-butyldiethoxysilane, diisobutyldiethoxysilane, di-sec-butyldiethoxysilane, di-tert-butyldiethoxysilane, di-n-pentyldiethoxysilane, dineopentyldiethoxysilane, diisopentyldiethoxysilane, di-sec-pentyldiethoxysilane, di-tert-pentyldiethoxysilane, di(pentan-3-yl)diethoxysilane, di-n-hexyldiethoxysilane, di-n-heptyldiethoxysilane, di-n Dialkyldiethoxysilanes such as di-n-octyldiethoxysilane, di-2-ethylhexyldiethoxysilane, di-n-nonyldiethoxysilane, di-n-decyldiethoxysilane, di-n-undecyldiethoxysilane, di-n-dodecyldiethoxysilane, di-n-tridecyldiethoxysilane, di-n-tetradecyldiethoxysilane, di-n-pentadecyldiethoxysilane, di-n-hexadecyldiethoxysilane, di-n-heptadecyldiethoxysilane, di-n-octadecyldiethoxysilane, di-n-nonadecyldiethoxysilane, and di-n-icosyldiethoxysilane;

[0049] The monofunctional silane compound (A3) is preferably a compound represented by the following formula (a3). Si(R a1 )3R a2 (a3) (In formula (a3), R a1 is a hydrocarbon group having 1 to 20 carbon atoms, and R a2 is a group that generates a silanol group upon hydrolysis, and three R a1 may be the same or different.)

[0050] In formula (a3), R a1 hydrocarbon groups as R a2 The group that generates a silanol group upon hydrolysis as described above is as described for formula (a1).

[0051] Specific preferred examples of the trifunctional silane compound (A3) include trimethylmethoxysilane, triethylmethoxysilane, tri-n-propylmethoxysilane, triisopropylmethoxysilane, tri-n-butylmethoxysilane, triisobutylmethoxysilane, tri-sec-butylmethoxysilane, tri-tert-butylmethoxysilane, tri-n-pentylmethoxysilane, trineopentylmethoxysilane, triisopentylmethoxysilane, tri-sec-pentylmethoxysilane, tri-tert-pentylmethoxysilane, tri(pentan-3-yl)methoxysilane, tri-n-hexylmethoxysilane, tri- trialkylmethoxysilanes such as n-heptylmethoxysilane, tri-n-octylmethoxysilane, tri-2-ethylhexylmethoxysilane, tri-n-nonylmethoxysilane, tri-n-decylmethoxysilane, tri-n-undecylmethoxysilane, tri-n-dodecylmethoxysilane, tri-n-tridecylmethoxysilane, tri-n-tetradecylmethoxysilane, tri-n-pentadecylmethoxysilane, tri-n-hexadecylmethoxysilane, tri-n-heptadecylmethoxysilane, tri-n-octadecylmethoxysilane, tri-n-nonadecylmethoxysilane, and tri-n-icosylmethoxysilane;Trimethylethoxysilane, triethylethoxysilane, tri-n-propylethoxysilane, triisopropylethoxysilane, tri-n-butylethoxysilane, triisobutylethoxysilane, tri-sec-butylethoxysilane, tri-tert-butylethoxysilane, tri-n-pentylethoxysilane, trineopentylethoxysilane, triisopentylethoxysilane, tri-sec-pentylethoxysilane, di-tert-pentylethoxysilane, tri(pentan-3-yl)ethoxysilane, di-n-hexylethoxysilane, tri-n-heptylethoxysilane, tri-n trialkylethoxysilanes such as n-octylethoxysilane, tri-2-ethylhexylethoxysilane, tri-n-nonylethoxysilane, tri-n-decylethoxysilane, tri-n-undecylethoxysilane, tri-n-dodecylethoxysilane, tri-n-tridecylethoxysilane, tri-n-tetradecylethoxysilane, tri-n-pentadecylethoxysilane, tri-n-hexadecylethoxysilane, tri-n-heptadecylethoxysilane, tri-n-octadecylethoxysilane, tri-n-nonadecylethoxysilane, and tri-n-icosylethoxysilane;

[0052] The content of the bifunctional silane compound (A2) represented by formula (a2) and the content of the monofunctional silane compound (A3) represented by formula (a3) in the hydrolyzable silane compound to be subjected to hydrolytic condensation are not particularly limited as long as the desired effect can be obtained. The content of the bifunctional silane compound (A2) represented by formula (a1) in the hydrolyzable silane compound to be subjected to hydrolytic condensation is preferably from 0 to 50% by mass, more preferably from 0 to 30% by mass, even more preferably from 0 to 20% by mass, and particularly preferably from 0 to 10% by mass, relative to the total mass of the hydrolyzable silane compound.

[0053] The content of the monofunctional silane compound (A3) represented by formula (a3) in the hydrolyzable silane compound to be subjected to hydrolysis and condensation is preferably as low as possible. This is because when the hydrolyzable silane compound contains the monofunctional silane compound (A3), the silanol groups of the silane condensate (A) are blocked, resulting in a decrease in the number of silanol groups of the silane condensate (A). If the number of silanol groups of the silane condensate (A) decreases, the silane condensate is less likely to adhere or bond well to the surfaces of substrates and three-dimensional structures.

[0054] The content of the monofunctional silane compound (A3) represented by formula (a3) in the hydrolyzable silane compound to be subjected to hydrolytic condensation is preferably 0% by mass or more and 10% by mass or less, more preferably 0% by mass or more and 5% by mass or less, even more preferably 0% by mass or more and 3% by mass or less, and particularly preferably 0% by mass or more and 1% by mass or less, based on the total mass of the hydrolyzable silane compound.

[0055] The hydrolyzable silane compound explained above is subjected to hydrolysis and condensation to produce the silane condensate (A).

[0056] The collapse prevention method preferably includes preparing a surface treatment liquid by a method including hydrolyzing and condensing the hydrolyzable silane compound to prepare a silane condensate (A).

[0057] The method for carrying out the hydrolysis and condensation of the hydrolyzable silane compound is not particularly limited, and any well-known hydrolysis and condensation method can be appropriately adopted as the method for hydrolysis and condensation of the hydrolyzable silane compound. The hydrolysis and condensation is carried out so that the reaction rate shown in the following formula is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. By carrying out the hydrolysis and condensation in this manner, it is easy to obtain a surface treatment solution that has an excellent collapse-inhibiting effect. Reaction rate (%) = (1-[A'] / [A]) x 100 (%) (In the formula, [A] is the concentration of the hydrolyzable silane compound at the start of the reaction, and [A'] is the concentration of the unreacted hydrolyzable silane compound at the time of measuring the reaction rate.) The concentrations used to calculate the reaction rate are 29 It can be calculated from the integral value of the Si-NMR peak. Specifically, when propylene glycol monomethyl ether acetate is used as the main solvent, it can be calculated from the integral value of the peak of the hydrolyzable silane compound (or unreacted hydrolyzable silane compound) when compared with the reference peak of decamethylcyclopentasiloxane (D5 Siloxane) that appears at -21.9±1 ppm.

[0058] A preferred method for preparing a surface treatment liquid containing the silane condensate (A) includes carrying out hydrolysis and condensation of a hydrolyzable silane compound in a reaction solvent containing an organic solvent (S) in the presence of a Brønsted acid to produce the silane condensate (A), and then diluting the reaction liquid obtained by the hydrolysis and condensation with the organic solvent (S) to obtain a surface treatment liquid in which the concentration of the silane condensate (A) is adjusted to 0.00005 mass % or more and 40 mass % or less. By carrying out the hydrolysis condensation at a relatively high concentration, the reaction can be progressed smoothly, and then, by diluting the reaction liquid containing the silane condensate (A), further condensation of the silane condensate (A) can be suppressed, and the stability over time of the surface treatment liquid can be improved. From the viewpoint of achieving both stability over time of the surface treatment liquid and an excellent effect of suppressing collapse, the concentration of the silane condensate (A) in the surface treatment liquid is preferably from 0.00005 to 40% by mass, more preferably from 0.00005 to 30% by mass, even more preferably from 0.0001 to 20% by mass, still more preferably from 0.001 to 10% by mass, particularly preferably from 0.002 to 5% by mass, and most preferably from 0.003 to 4% by mass.

[0059] The organic solvent (S) used for the hydrolysis and condensation of the hydrolyzable silane compound and for diluting the reaction liquid obtained by the hydrolysis and condensation is not particularly limited as long as the hydrolysis and condensation proceeds smoothly and the silane condensate (A) is soluble in the organic solvent.

[0060] Specific preferred examples of the organic solvent (S) include glycol monoethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, and diethylene glycol monophenyl ether; glycol diethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol dipropyl ether; glycol monoacetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, and diethylene glycol monoethyl ether acetate;Diethylene glycol monopropyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monophenyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 2-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate monoether monoacetates of diols such as acetone, 3-ethyl-3-methoxybutyl acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, and 4-methyl-4-methoxypentyl acetate; Ketones such as diethyl ketone, diethyl ketone, methyl isobutyl ketone, ethyl isobutyl ketone, and cyclohexanone; methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, 2-hydroxy-2-methyl, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-propoxypropionate, propyl 3-methoxypropionate esters such as methyl acetoacetate, isopropyl-3-methoxypropionate, ethyl ethoxyacetate, ethyl oxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isoamyl acetate, methyl carbonate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, and γ-butyrolactone;Examples of suitable organic solvents include ethers such as diethyl ether, dipropyl ether, dibutyl ether, dihexyl ether, benzyl methyl ether, benzyl ethyl ether, and tetrahydrofuran; aromatic solvents such as benzene, toluene, xylene, ethylbenzene, cresol, and chlorobenzene; aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, n-hexanol, and cyclohexanol; glycols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; glycerin; and aprotic polar organic solvents such as N,N,N',N'-tetramethylurea, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoramide, 1,3-dimethyl-2-imidazolidinone, and dimethyl sulfoxide. The organic solvent (S) may be a hydrocarbon solvent such as an aliphatic hydrocarbon such as n-hexane, cyclohexane, n-heptane, n-octane, n-nonane, methyloctane, n-decane, n-undecane, or n-dodecane, or a terpene solvent such as a menthane such as p-menthane, o-menthane, or m-menthane; a terpinene such as diphenylmenthane, limonene, α-terpinene, β-terpinene, or γ-terpinene; a pinene such as bornane, norbornane, pinane, α-pinene, or β-pinene; a monoterpene such as carane or longifolene; or a diterpene such as abietane.

[0061] The organic solvent (S) used in the hydrolysis condensation is preferably an aliphatic alcohol, a glycol, glycerin, glycol monoether, or the like. The organic solvent (S) used to dilute the reaction mixture obtained by hydrolysis and condensation is preferably an aliphatic alcohol, a glycol, glycerin, glycol monoether, or a monoether monoacetate of a diol.

[0062] The hydrolyzable silane compound can undergo hydrolysis and condensation by moisture in the air. However, in order to efficiently proceed with the hydrolysis and condensation, it is preferable to carry out the hydrolysis and condensation in a reaction liquid containing water together with the organic solvent (S).

[0063] The amount of water used is not particularly limited as long as the hydrolysis condensation proceeds smoothly. The amount of water used in the hydrolysis condensation is preferably 10 parts by mass or more and 100 parts by mass or less, more preferably 15 parts by mass or more and 70 parts by mass or less, and even more preferably 20 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the hydrolyzable silane compound.

[0064] In the hydrolysis condensation, the organic solvent (S) and water are used so that the concentration of the hydrolyzable silane compound in the reaction liquid is preferably 20% by mass or more and 70% by mass or less, more preferably 25% by mass or more and 60% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less.

[0065] The hydrolysis condensation is preferably carried out in the presence of a Brønsted acid. The Brønsted acid is not particularly limited as long as it is a compound that exhibits acidity according to the Brønsted definition. Preferred examples of the Brønsted acid include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, acrylic acid, methacrylic acid, malonic acid, succinic acid, maleic acid, and fumaric acid; aromatic carboxylic acids such as benzoic acid, 1-naphthoic acid, and 2-naphthoic acid; and organic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, benzenesulfonic acid, and toluenesulfonic acid. Among these, aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, acrylic acid, methacrylic acid, malonic acid, succinic acid, maleic acid, and fumaric acid are preferred, from the viewpoints of being less likely to corrode the reaction vessel, the substrate, and the three-dimensional structure, being easily dissolved in the reaction liquid, and easily allowing hydrolysis condensation to proceed favorably, with formic acid, acetic acid, propionic acid, acrylic acid, and methacrylic acid being more preferred, and acetic acid being particularly preferred.

[0066] The amount of the Bronsted acid used in the hydrolysis condensation is preferably 1 part by mass or more and 100 parts by mass or less, more preferably 5 parts by mass or more and 70 parts by mass or less, and even more preferably 10 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the hydrolyzable silane compound at the start of the reaction.

[0067] The conditions for the hydrolysis condensation are not particularly limited as long as the hydrolysis condensation proceeds to a desired extent. The hydrolysis condensation is carried out, for example, preferably at 0°C or higher and 80°C or lower, more preferably at 10°C or higher and 50°C or lower. The reaction time for the hydrolysis condensation is, for example, preferably 12 hours or higher and 90 days or lower, more preferably 50 hours or higher and 60 days or lower, and even more preferably 80 hours or higher and 20 days or lower.

[0068] The silane condensate (A) typically contains oligomers such as dimers, trimers, pentamers, hexamers, heptamers, etc. The content of oligomers in the silane condensate (A) is not particularly limited. The content of the dimer in the silane condensate (A) is preferably 10 area % or less, more preferably 5 area % or less, and particularly preferably 3 area % or less, relative to the total area of the silane condensate (A), from the viewpoints of the collapse suppression effect and the stability of the surface treatment liquid. In terms of the collapse suppression effect, the total content of trimer, tetramer, and pentamer in the silane condensate is preferably 50 area% or more and 100 area% or less, more preferably 60 area% or more and 95 area% or less, and particularly preferably 70 area% or more and 90 area% or less, based on the total area of the silane condensate (A). In terms of the collapse suppression effect, the content of the tetramer in the silane condensate (A) is preferably 30 area % or more and 70 area % or less, more preferably 40 area % or more and 60 area % or less, based on the total area of the silane condensate (A). The above "area %" refers to the area % for each oligomer in the chromatogram obtained when the silane condensate (A) is analyzed by gel permeation chromatography (GPC).

[0069] The surface treatment liquid preferably contains a silane condensate (A), an organic solvent (S), and a Bronsted acid. The Bronsted acid acts catalytically during the surface treatment and can promote the adhesion or bonding of the silane condensate (A) to the surface of the substrate and the three-dimensional structure. Suitable examples of the Bronsted acid are the same as those used in the hydrolysis condensation. When the hydrolysis and condensation is carried out using a Bronsted acid, the Bronsted acid used in the hydrolysis and condensation may remain as it is in the surface treatment liquid.

[0070] The suitable content of the Brønsted acid in the surface treatment liquid is preferably 1 part by mass or more and 100 parts by mass or less, more preferably 5 parts by mass or more and 70 parts by mass or less, and even more preferably 10 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the silane condensate (A) contained in the surface treatment liquid.

[0071] The surface treatment solution may contain various additives in addition to the silane condensate (A) and the organic solvent (S), provided that the object of the present invention is not impaired. Examples of the additives include a surfactant, a viscosity modifier, an antifoaming agent, and a colorant.

[0072] By performing the surface treatment of a substrate having a three-dimensional structure on its surface according to the above-mentioned method, a substrate can be obtained having a silane condensate (A) attached or bonded to the surface of the three-dimensional structure, the silane condensate (A) being a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound including the trifunctional silane compound (A1) represented by the above-mentioned formula (a1). In such a substrate, the surface of the three-dimensional structure is well hydrophobized, thereby preventing the three-dimensional structure from collapsing.

[0073] <Surface treatment method> As described above, the surface treatment liquid effectively renders the surfaces of various materials hydrophobic. The surface treatment using the above-mentioned surface treatment liquid is useful for making the surface of a three-dimensional structure hydrophobic when the surface of the substrate has a three-dimensional structure patterned thereon. Specifically, the surface treatment method is providing a substrate having a patterned three-dimensional structure on its surface; and bringing the surface of the three-dimensional structure into contact with a surface treatment liquid. Hereinafter, the "preparation step" of preparing a substrate having a three-dimensional structure patterned on its surface, and the "surface treatment step" of bringing the surface of the three-dimensional structure into contact with a surface treatment liquid are both the same as the "preparation step" and "surface treatment step" described in the collapse prevention method. [Example]

[0074] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

[0075] Example 1 40 parts by mass of n-octyltrimethoxysilane, 11.5 parts by mass of pure water, 37 parts by mass of isopropyl alcohol, and 11.5 parts by mass of acetic acid were uniformly mixed, and then the resulting mixture was stirred at room temperature for 43 hours to carry out hydrolysis and condensation. The reaction rate of the reaction solution after hydrolysis and condensation was calculated based on the following formula, and was found to be 90%. Reaction rate (%) = (1-[A'] / [A]) x 100 (In the formula, [A] is the concentration of the hydrolyzable silane compound at the start of the reaction, and [A'] is the concentration of the unreacted hydrolyzable silane compound at the time of measuring the reaction rate.) The concentrations used to calculate the reaction rate are 29 The calculation was based on the integral value of the Si-NMR peak. Specifically, when propylene glycol monomethyl ether acetate was used as the main solvent, the calculation was based on the integral value of the peak of the hydrolyzable silane compound (or unreacted hydrolyzable silane compound) compared to the reference peak of decamethylcyclopentasiloxane (D5 Siloxane) that appears at -21.9±1 ppm. The resulting reaction solution after hydrolysis and condensation was diluted 20 times by mass with propylene glycol monomethyl ether acetate to obtain a surface treatment solution, in which the concentration of the silane condensate (A) was approximately 2% by mass. The diluted surface treatment solution was used to treat the surfaces of silicon oxide (SiOx) substrates and silicon nitride (SiN) substrates 51 days after dilution. First, a silicon oxide (SiOx) substrate and a silicon nitride (SiN) substrate were immersed in a surface treatment solution for 1 minute, then immersed in ion-exchanged distilled water for 1 minute, immersed in isopropyl alcohol for 1 minute, and dried by nitrogen blowing, in that order, to obtain surface-treated silicon oxide (SiOx) substrates and silicon nitride (SiN) substrates. Before the surface treatment, the substrate to be surface-treated was immersed in a dilute hydrofluoric acid aqueous solution with a concentration of 0.1% by mass for 1 minute, immersed in ion-exchanged distilled water for 1 minute, immersed in isopropyl alcohol for 1 minute, and then dried by nitrogen blowing, in that order. The contact angle of each surface-treated substrate was then measured using a Dropmaster 700 (Kyowa Interface Science Co., Ltd.). Specifically, a droplet of pure water (1.8 μL) was dropped onto the surface of the substrate, and the contact angle was measured 7 times 10 seconds after the drop. The average value was used as the contact angle value. The standard deviation was 3°. The water contact angles of each substrate after surface treatment are shown in Table 1.

[0076] [Examples 2 to 8] The preparation of the surface treatment solution and the surface treatment of a silicon oxide (SiOx) substrate and a silicon nitride (SiN) substrate were carried out in the same manner as in Example 1, except that the reaction time for hydrolysis and condensation and the time elapsed since dilution of the surface treatment solution at the time of carrying out the surface treatment were changed to the times shown in Table 1. The reaction rate at the end of hydrolysis and condensation and the water contact angle of each substrate after the surface treatment are shown in Table 1.

[0077] [Table 1]

[0078] Table 1 shows that silicon oxide or silicon nitride can be effectively hydrophobized by using a surface treatment liquid containing, as the silane condensate (A), a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound including the trifunctional silane compound (A1) represented by the above-mentioned formula (a1), in a concentration ranging from 0.00005% by mass to 40% by mass. This shows that when the substrate has a three-dimensional structure made of silicon oxide or silicon nitride, the above surface treatment can prevent the three-dimensional structure from collapsing. Furthermore, the results of Examples 1, 5, and 7 show that the above surface treatment liquid has excellent stability over time.

[0079] Example 9 Using the surface treatment solution obtained in Example 3, surface treatment was performed on silicon oxide (SiOx) substrates, silicon nitride (SiN) substrates, carbon substrates, tungsten substrates, titanium nitride substrates, titanium oxide (TiOx) substrates, and aluminum oxide (AlOx) substrates. Specifically, the surface treatment of each substrate was carried out in the same manner as in Example 1, except that the immersion time of the substrate in the surface treatment solution was changed to the time shown in Table 2. Table 2 shows the water contact angle of each substrate before and after the surface treatment.

[0080] [Table 2]

[0081] Table 2 shows that various materials can be effectively hydrophobized by using a surface treatment liquid containing, as the silane condensate (A), a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound including the trifunctional silane compound (A1) represented by the above-mentioned formula (a1), in a concentration ranging from 0.00005% by mass to 40% by mass. This shows that when the substrate has a three-dimensional structure made of the material listed in Table 2, the collapse of the three-dimensional structure can be prevented by the above surface treatment.

[0082] [Examples 10 to 12] A surface treatment liquid was obtained in the same manner as in Example 3, except that the dilution ratio after completion of hydrolysis and condensation was changed to the ratio shown in Table 3. Using the surface treatment liquid of Example 3 and the surface treatment liquids of Examples 10 to 12, surface treatments were carried out on silicon oxide (SiOx) substrates, silicon nitride (SiN) substrates, carbon substrates, and tungsten substrates in the same manner as in Example 1. Table 3 shows the water contact angle of each substrate after the surface treatment.

[0083] [Table 3]

[0084] Table 3 shows that by using a surface treatment liquid containing a silane condensate (A), which is a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound including the trifunctional silane compound (A1) represented by the above-mentioned formula (a1), in a concentration ranging from 0.00005 mass % to 40 mass %, various materials can be effectively hydrophobized regardless of the concentration of the silane condensate (A) in the surface treatment liquid.

[0085] [Comparative Examples 1 to 6] The surface treatment solutions of Comparative Examples 1 to 6 were obtained by dissolving each of the additive components shown in Table 4 in propylene glycol monomethyl ether acetate at the concentrations shown in Table 4. The additive components shown in Table 4 are as follows. A1: n-Decyltrichlorosilane A2: n-Decyldimethylchlorosilane A3: n-Octyldimethylchlorosilane A4: n-propyltrichlorosilane A5: n-propyldimethylchlorosilane A6: Decamethylcyclopentasiloxane Using the obtained surface treatment solutions of Comparative Examples 1 to 6, surface treatments were carried out under the conditions of immersion times in the surface treatment solutions of 1 minute and 3 minutes in the same manner as in Example 1. Note that for Comparative Example 6, the surface treatment was not carried out under the condition of immersion time of 3 minutes. Table 4 shows the water contact angle of each substrate after the surface treatment.

[0086] [Table 4]

[0087] Table 4 shows that silicon oxide (SiOx) and silicon nitride (SiN) cannot be satisfactorily hydrophobized when surface treatment is performed using a surface treatment solution containing various silane compounds other than the aforementioned silane condensate (A). Furthermore, a comparison of the results for 1 minute of immersion with the results for 3 minutes of immersion shows that when the surface treatment solutions of Comparative Examples 1 to 6 are used, the hydrophobization effect does not increase even if the immersion time is extended.

[0088] Example 13 The formation of silanol-containing silane condensates by hydrolysis of n-octyltriethoxysilane was monitored by gel permeation chromatography (GPC). First, the two reactants, n-octyltrimethoxysilane and water, were mixed with acetic acid in 2-propanol, which led to a very rapid hydrolysis reaction, which resulted in the formation of silanol groups and condensation between the silanol groups, resulting in the formation of silane condensates (oligomers) with silanol groups. FIG. 1 shows a GPC chromatogram of the reaction raw material n-octyltrimethoxysilane and a GPC chromatogram of the reaction mixture. Figure 1 (a) shows a chromatogram of the reaction raw material, n-octyltrimethoxysilane. Figure 1 (b) shows a GPC chromatogram of the reaction mixture containing silane condensates (oligomers) one day after mixing the raw materials. Figure 1 (c) shows a GPC chromatogram of the reaction mixture containing silane condensates (oligomers) five days after mixing the raw materials. The chromatogram in Figure 1 shows that the raw material n-octyltrimethoxysilane has reacted completely, producing a silane condensate (oligomer). The chromatogram in Figure 1 shows that the peak at a retention time of 4.85 minutes, which corresponds to the reaction raw material n-octyltrimethoxysilane, disappeared one day after mixing the raw materials, and a new peak appeared between retention times of 4.00 and 4.70 minutes. Furthermore, according to the chromatograms (b) and (c) in Figure 1, the change in peak shape indicates that the molecular weight of the silane condensate (oligomer) produced after 5 days from mixing the raw materials has shifted to a higher molecular weight side than after 1 day.

[0089] Figure 2 shows a GPC chromatogram of the reaction raw material n-octyltrimethoxysilane, a GPC chromatogram of the reaction mixture, and a chromatogram of the solution containing the reaction product diluted with propylene glycol monomethyl ether acetate (PGMEA) after the reaction was completed. Figure 2 (a) is a chromatogram of the reaction raw material, n-octyltrimethoxysilane. Figure 2 (b) is a GPC chromatogram of the reaction mixture containing silane condensation products (oligomers) five days after mixing the raw materials. Figure 2 (c) is a GPC chromatogram of the liquid obtained by diluting the reaction mixture containing silane condensation products (oligomers) with PGMEA five days after mixing the raw materials.

[0090] The molecular weight of the product was analyzed by gel permeation chromatography (GPC). Molecular weight calibration was performed by identifying peaks in the chromatogram using a polystyrene calibration standard. The molecular weight of the reaction raw material, n-octyltrimethoxysilane, was 276.49. FIG. 3 shows a chromatogram of the silane condensate (oligomer) contained in the reaction mixture one day after mixing the raw materials. Molecular weight analysis reveals that the peak at retention time 4.614 minutes corresponds to a dimer with a molecular weight of 384. Table 5 shows the results of the molecular weight analysis for the chromatogram shown in Figure 3. Mn is the number average molecular weight. Mw is the weight average molecular weight. Mp is the peak top molecular weight. Table 6 shows some of the possible structures of the oligomers and their molecular weights.

[0091] [Table 5]

[0092] [Table 6]

[0093] FIG. 4 shows a chromatogram of the silane condensate (oligomer) contained in the reaction mixture five days after mixing the raw materials. Table 7 shows the results of the molecular weight analysis for the chromatogram shown in Figure 4. Mn is the number average molecular weight. Mw is the weight average molecular weight. Mp is the peak top molecular weight.

[0094] [Table 7]

[0095] Molecular weight analysis shows that the raw material n-octyltriethoxysilane reacts in one day to produce oligomers with large molecular weights. Furthermore, Tables 5 and 7 show that oligomers with small molecular weights, such as dimers, produced oligomers and heptamers with larger molecular weights over the course of 1 to 5 days.

[0096] Table 4 shows the ratio of each oligomer contained in the reaction mixture. [Table 8]

Claims

1. providing a substrate having a patterned three-dimensional structure on its surface; and contacting the surface of the three-dimensional structure with a surface treatment liquid, the surface treatment liquid contains a silane condensate (A) and an organic solvent (S), The silane condensate (A) is represented by the following formula (a1): SiR ａ１ (R ａ２ ) ３ ・・・(a1) (In formula (a1), R ａ１ is an alkyl group having 8 to 20 carbon atoms, and R ａ２ is an alkoxy group having 1 or 2 carbon atoms, and three R ａ２ may be the same or different from each other. ａ２ is not an organic group represented by the following formula (a1-1). The following formula (a1-1): 【Chemical 1】 (In formula (a1-1), R Ａ１ and R Ａ２ each independently represents a linear or branched alkylene group having 1 to 3 carbon atoms; R Ａ３ represents an alkoxy group having 1 to 4 carbon atoms, an allyloxy group, or a hydroxy group, and p represents 0, 1, or 2. a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the following formula: a concentration of the silane condensate (A) in the surface treatment liquid is 0.00005% by mass or more and 40% by mass or less, the total content of trimer, tetramer, and pentamer in each oligomer contained in the silane condensate (A) is 50 area% or more and 100 area% or less, based on the total area of the silane condensate (A); the content of the tetramer in the silane condensate (A) is 30 area % or more and 70 area % or less, based on the total area of the silane condensate (A); The method for inhibiting collapse of a three-dimensional structure, wherein the area % is the area % for each of the oligomers in the chromatogram obtained when the silane condensate (A) is analyzed by gel permeation chromatography (GPC).

2. The method for suppressing collapse of a three-dimensional structure according to claim 1, comprising preparing the surface treatment liquid by hydrolyzing and condensing the hydrolyzable silane compound to prepare the silane condensate (A).

3. the hydrolysis and condensation of the hydrolyzable silane compound is carried out in a reaction solvent containing an organic solvent (S) in the presence of a Bronsted acid, 3. The method for suppressing collapse of a three-dimensional structure according to claim 2, wherein the reaction liquid obtained by the hydrolysis and condensation is diluted with an organic solvent (S) so that the concentration of the silane condensate (A) in the surface treatment liquid is adjusted to 0.00005% by mass or more and 40% by mass or less.

4. 4. The method for suppressing collapse of a three-dimensional structure according to claim 2, wherein the hydrolysis and condensation of the hydrolyzable silane compound is carried out so that the reaction rate represented by the following formula is 80% or more. Reaction rate (%) = (1 - [A'] / [A]) x 100 (In the formula, [A] is the concentration of the hydrolyzable silane compound at the start of the reaction, and [A′] is the concentration of the unreacted hydrolyzable silane compound at the time of measuring the reaction rate.)

5. In the formula (a1), the R ａ１ The method for suppressing the collapse of a three-dimensional structure according to any one of claims 1 to 4, wherein is an alkyl group having 8 to 12 carbon atoms.

6. The method for inhibiting collapse of a three-dimensional structure according to any one of claims 1 to 5, wherein the surface treatment solution contains a Bronsted acid.

7. The method for suppressing collapse of a three-dimensional structure according to claim 6 , wherein the Bronsted acid is an aliphatic carboxylic acid.

8. The method for suppressing collapse of a three-dimensional structure according to any one of claims 1 to 7, wherein the ratio of the mass of the trifunctional silane compound to the mass of the hydrolyzable silane compound is 90 mass% or more.

9. 1. A method for producing a surface treatment liquid to be brought into contact with a three-dimensional structure patterned on a substrate, the method comprising: the surface treatment liquid contains a silane condensate (A) and an organic solvent (S), a concentration of the silane condensate (A) in the surface treatment liquid is 0.00005% by mass or more and 40% by mass or less, The following formula (a1): SiR ａ１ (R ａ２ ) ３ ・・・(a1) (In formula (a1), R ａ１ is an alkyl group having 8 to 20 carbon atoms, and R ａ２ is an alkoxy group having 1 or 2 carbon atoms, and three R ａ２ may be the same or different from each other. ａ２ is not an organic group represented by the following formula (a1-1). The following formula (a1-1): 【Chemistry 2】 (In formula (a1-1), R Ａ１ and R Ａ２ each independently represents a linear or branched alkylene group having 1 to 3 carbon atoms; R Ａ３ represents an alkoxy group having 1 to 4 carbon atoms, an allyloxy group, or a hydroxy group, and p represents 0, 1, or 2. and hydrolyzing and condensing a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the formula: the total content of trimer, tetramer, and pentamer in each oligomer contained in the silane condensate (A) is 50 area% or more and 100 area% or less, based on the total area of the silane condensate (A); the content of the tetramer in the silane condensate (A) is 30 area % or more and 70 area % or less, based on the total area of the silane condensate (A); the area % is the area % for each of the oligomers in a chromatogram obtained when the silane condensate (A) is analyzed by gel permeation chromatography (GPC).

10. the hydrolysis and condensation of the hydrolyzable silane compound is carried out in a reaction solvent containing an organic solvent (S) in the presence of a Bronsted acid, 10. The method for producing a surface treatment liquid according to claim 9, wherein the reaction liquid obtained by the hydrolysis and condensation is diluted with an organic solvent (S) to adjust the concentration of the silane condensate (A) in the surface treatment liquid to 0.00005 mass% or more and 40 mass% or less.

11. A surface treatment liquid to be brought into contact with a three-dimensional structure patterned on a substrate, the surface treatment liquid comprising: the surface treatment liquid contains a silane condensate (A) and an organic solvent (S), The silane condensate (A) is represented by the following formula (a1): SiR ａ１ (R ａ２ ) ３ ・・・(a1) (In formula (a1), R ａ１ is an alkyl group having 8 to 20 carbon atoms, and R ａ２ is an alkoxy group having 1 or 2 carbon atoms, and three R ａ２ may be the same or different from each other. ａ２ is not an organic group represented by the following formula (a1-1). The following formula (a1-1): 【Chemistry 3】 (In formula (a1-1), R Ａ１ and R Ａ２ each independently represents a linear or branched alkylene group having 1 to 3 carbon atoms; R Ａ３ represents an alkoxy group having 1 to 4 carbon atoms, an allyloxy group, or a hydroxy group, and p represents 0, 1, or 2. a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the following formula: a concentration of the silane condensate (A) in the surface treatment liquid is 0.00005% by mass or more and 40% by mass or less, the total content of trimer, tetramer, and pentamer in each oligomer contained in the silane condensate (A) is 50 area% or more and 100 area% or less, based on the total area of the silane condensate (A); the content of the tetramer in the silane condensate (A) is 30 area % or more and 70 area % or less, based on the total area of the silane condensate (A); The surface treatment solution, wherein the area % is the area % for each of the oligomers in the chromatogram obtained when the silane condensate (A) is analyzed by gel permeation chromatography (GPC).

12. A substrate having a patterned three-dimensional structure on its surface, The surface of the three-dimensional structure is provided with the following formula (a1): SiR ａ１ (R ａ２ ) ３ ・・・(a1) (In formula (a1), R ａ１ is an alkyl group having 8 to 20 carbon atoms, and R ａ２ is an alkoxy group having 1 or 2 carbon atoms, and three R ａ２ may be the same or different from each other. ａ２ is not an organic group represented by the following formula (a1-1). The following formula (a1-1): 【Chemistry 4】 (In formula (a1-1), R Ａ１ and R Ａ２ each independently represents a linear or branched alkylene group having 1 to 3 carbon atoms; R Ａ３ represents an alkoxy group having 1 to 4 carbon atoms, an allyloxy group, or a hydroxy group, and p represents 0, 1, or 2. a silane condensate (A) obtained by hydrolysis and condensation of a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the following formula: the total content of trimer, tetramer, and pentamer in each oligomer contained in the silane condensate (A) is 50 area% or more and 100 area% or less, based on the total area of the silane condensate (A); the content of the tetramer in the silane condensate (A) is 30 area % or more and 70 area % or less, based on the total area of the silane condensate (A); A substrate to which the silane condensate (A) is attached or bonded, wherein the area % is the area % for each of the oligomers in a chromatogram obtained when the silane condensate (A) is analyzed by gel permeation chromatography (GPC).

13. providing a substrate having a patterned three-dimensional structure on its surface; and contacting the surface of the three-dimensional structure with a surface treatment liquid, the surface treatment liquid contains a silane condensate (A) and an organic solvent (S), The silane condensate (A) is represented by the following formula (a1): SiR ａ１ (R ａ２ ) ３ ・・・(a1) (In formula (a1), R ａ１ is an alkyl group having 8 to 20 carbon atoms, and R ａ２ is an alkoxy group having 1 or 2 carbon atoms, and three R ａ２ may be the same or different from each other. ａ２ is not an organic group represented by the following formula (a1-1). The following formula (a1-1): 【Chemistry 5】 (In formula (a1-1), R Ａ１ and R Ａ２ each independently represents a linear or branched alkylene group having 1 to 3 carbon atoms; R Ａ３ represents an alkoxy group having 1 to 4 carbon atoms, an allyloxy group, or a hydroxy group, and p represents 0, 1, or 2. a condensate obtained by hydrolysis and condensation of a hydrolyzable silane compound containing a trifunctional silane compound (A1) represented by the following formula: a concentration of the silane condensate (A) in the surface treatment liquid is 0.00005% by mass or more and 40% by mass or less, the total content of trimer, tetramer, and pentamer in each oligomer contained in the silane condensate (A) is 50 area% or more and 100 area% or less, based on the total area of the silane condensate (A); the content of the tetramer in the silane condensate (A) is 30 area % or more and 70 area % or less, based on the total area of the silane condensate (A); The surface treatment method for a three-dimensional structure on a substrate having a three-dimensional structure patterned on its surface, wherein the area % is the area % for each of the oligomers in a chromatogram obtained when the silane condensate (A) is analyzed by gel permeation chromatography (GPC).

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