Wiring substrate, method for manufacturing wiring substrate, and composition for forming barrier film

Abstract

A wiring substrate which directly or indirectly includes a barrier film on a substrate having a copper wiring, and the barrier film contains a flaky titanium oxide or a flaky titanium-metal composite oxide.

Description

Technical Field

[0001] This invention relates to a wiring substrate, a method for manufacturing the wiring substrate, and a composition for forming a barrier film. Background Technology

[0002] With the increasing integration of semiconductor devices, there is a demand for further miniaturization of wiring. In order to suppress the increase in wiring resistance caused by the miniaturization of wiring, Cu (copper), which has higher conductivity, is used as the wiring material instead of Al (aluminum), which has been used before.

[0003] Regarding Cu wiring, since Cu is difficult to pattern in fine detail using methods such as dry etching, it is formed using a so-called damascene method. In this damascene method, firstly, fine wiring trenches corresponding to a predetermined wiring pattern are formed using SiO2 (silicon oxide). Next, Cu is deposited in the wiring trenches using a plating method, thereby forming a Cu film. The Cu film is formed to a thickness that fills the wiring trenches as much as possible and covers the entire surface area of ​​the substrate. Subsequently, the Cu film is polished using chemical mechanical polishing (CMP). The polishing of the Cu film continues until all the portion of the Cu film outside the wiring trenches is removed, and the surface of the silicon oxide film outside the wiring trenches is exposed. Thus, only the Cu film remains within the wiring trenches, resulting in Cu wiring embedded within the wiring trenches.

[0004] Compared to Al, Cu has a higher diffusion rate into silicon oxide films. Therefore, if Cu wiring (Cu film) is formed directly on a silicon oxide film, Cu diffusion within the silicon oxide film may cause short circuits between wirings.

[0005] Furthermore, recent advancements in the miniaturization and multilayering of Cu wiring have raised concerns about the increased resistance of wiring caused by oxidation of the Cu surface.

[0006] Therefore, in Cu wiring, a barrier film is needed to prevent Cu diffusion or oxidation of the Cu surface. As a method for forming such a barrier film, for example, a method has been proposed in which, before the formation of the Cu film, an alloy film containing an alloy of Cu and Mn (manganese) is formed on silicon oxide where wiring grooves are formed; after the formation of the Cu film, heat treatment is performed, thereby causing Mn in the alloy film to diffuse to the interface with the silicon oxide film, forming a Mn-containing layer at the interface. x Si y O z (x, y, z: numbers greater than 0) barrier film (refer to Japanese Patent Application Publication No. 2005-277390).

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2005-277390 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, in the proposed method, unwanted Mn residues remain in the Cu wiring, which do not contribute to the formation of the barrier film and lead to an increase in the resistance of the Cu wiring. Furthermore, the formation of this alloy film takes time, resulting in a decrease in the throughput of the wiring substrate.

[0012] Therefore, the object of the present invention is to provide a wiring substrate, a method for manufacturing the same, and a composition for forming a barrier film, the wiring substrate including a barrier film capable of suppressing oxidation of the surface of a copper film (copper wiring).

[0013] Technical means to solve the problem

[0014] The invention that addresses the aforementioned problem is a wiring substrate that includes a barrier film directly or indirectly on a substrate having copper wiring, and the barrier film contains sheet-like titanium oxide or sheet-like titanium-metal composite oxide.

[0015] Another invention made to solve the aforementioned problem is a method for manufacturing a wiring substrate (hereinafter, sometimes referred to as "method for manufacturing a wiring substrate (I)"), which manufactures the wiring substrate described above. The manufacturing method includes a step of directly or indirectly coating a barrier film forming composition onto a substrate having copper wiring, the barrier film forming composition containing: flake-shaped titanium oxide or flake-shaped titanium-metal composite oxide, or flake-shaped titanium acid, flake-shaped titanium-metal acid or salts thereof, and a solvent.

[0016] Another invention to solve the aforementioned problem is a method for manufacturing a wiring substrate (hereinafter sometimes referred to as "method for manufacturing a wiring substrate (II)"), which manufactures the wiring substrate described above. The manufacturing method includes: a step of directly or indirectly forming a polymer film on a substrate having copper wiring, and coating the polymer film with a barrier film forming composition; and a step of removing the polymer film, wherein the barrier film forming composition contains: flake-shaped titanium oxide or flake-shaped titanium-metal composite oxide, or flake-shaped titanium acid, flake-shaped titanium-metal acid, or salts thereof, and a solvent.

[0017] Another invention to address the aforementioned problem is a barrier film forming composition for manufacturing the wiring substrate described above. The barrier film forming composition contains: flake-shaped titanium oxide, or flake-shaped titanium-metal composite oxide, or flake-shaped titanium acid, flake-shaped titanium-metal acid, or salts thereof, and a solvent.

[0018] The effects of the invention

[0019] The present invention provides a wiring substrate, a method for manufacturing the same, and a composition for forming a barrier film, wherein the wiring substrate includes a barrier film that can suppress oxidation of the surface of a copper film (copper wiring). Attached Figure Description

[0020] [ Figure 1 ] Figure 1 This is a schematic diagram illustrating one aspect of the wiring board of the present invention.

[0021] [ Figure 2 ] Figure 2 This is a schematic diagram illustrating one aspect of the wiring board of the present invention.

[0022] [ Figure 3 ] Figure 3 This is a cross-sectional photograph of the Cu wiring in Example 1.

[0023] [ Figure 4 ] Figure 4 This is a cross-sectional photograph of the Cu wiring in Example 4.

[0024] [ Figure 5 ] Figure 5 This is a cross-sectional photograph of the Cu wiring in Comparative Example 1.

[0025] [ Figure 6 ] Figure 6 This is a cross-sectional photograph of the Cu wiring in Example 9.

[0026] [ Figure 7 ] Figure 7 This is a cross-sectional photograph of the Cu wiring in Example 13. Detailed Implementation

[0027] Hereinafter, the wiring substrate, the method for manufacturing the wiring substrate (I), the method for manufacturing the wiring substrate (II), and the composition for forming the barrier film of the present invention will be described in detail.

[0028] <Wireline board>

[0029] use Figure 1 The wiring substrate 1 will be described. The wiring substrate 1 includes a barrier film 4 directly or indirectly on a substrate 2 having copper wiring 3. Figure 1 The diagram illustrates a configuration where a barrier film 4 is directly incorporated onto a substrate 2 having copper wiring 3. For example... Figure 2 As shown, the wiring substrate 1 may also include an insulating film 5 between the substrate 2 with copper wiring 3 and the barrier film 4.

[0030] Materials used for substrate 2 include, for example, silicon substrates.

[0031] Copper wiring 3 can be formed, for example, by chemical vapor deposition (CVD), physical vapor deposition (PVD), electrolytic plating, or electroless plating. There are no particular limitations on the wiring width, spacing, and height of the copper wiring 3; for example, a wiring width and spacing of 20 μm and a wiring height of 7 μm to 8 μm can be used.

[0032] The substrate 2 having copper wiring 3 can be fabricated using known methods. For example, a silicon oxide film can be used on a silicon substrate to form wiring trenches by an etch method, copper can be embedded in the trenches, and then the silicon oxide film can be removed, thereby creating an exposed copper wiring pattern. The wiring trenches or exposed copper wiring patterns can be formed using known photolithography and etching techniques.

[0033] The barrier film 4 contains sheet-like titanium dioxide or sheet-like titanium-metal composite oxide. The barrier film 4 can be formed using the barrier film forming composition described later and by the method described later. When the barrier film 4 contains sheet-like titanium dioxide, it is preferable that, in the ultraviolet-visible absorption spectrum measured using a spectrophotometer (Hitachi, Ltd.'s "U-3300") in the wavelength range of 200 nm to 800 nm, it has an absorption peak in the wavelength range of 250 nm to 280 nm and no absorption peak in the wavelength range of 300 nm to 800 nm. When the barrier film 4 contains sheet-like titanium-metal composite oxide, it is preferable that, in the ultraviolet-visible absorption spectrum measured using the aforementioned spectrophotometer in the wavelength range of 200 nm to 800 nm, it has absorption peaks in both the wavelength range of 250 nm to 280 nm and the wavelength range of 300 nm to 800 nm.

[0034] The barrier film 4, containing flake-shaped titanium oxide or flake-shaped titanium-metal composite oxide, can suppress the oxidation of the copper film (copper wiring) surface. The reason for this, while not necessarily clear, is speculated as follows: The barrier film containing flake-shaped titanium oxide or flake-shaped titanium-metal composite oxide comprises a structure in which flake-shaped titanium oxide particles or flake-shaped titanium-metal composite oxide particles are arranged without gaps, and therefore is considered to have superior gas barrier properties compared to titanium oxide films formed by methods such as sputtering.

[0035] In addition, the barrier film 4 can be easily peeled off by dry etching.

[0036] The thickness of the barrier film 4 can be set to any thickness depending on the coating method. For example, it can be set to be greater than 1 nm and less than 50 nm.

[0037] The preferred form of the barrier film 4 is a titanium oxide film with a high substrate coverage, in which thin-film titanium oxide particles or thin-film titanium-metal composite oxide particles are oriented and arranged parallel to the substrate. Specifically, it is a titanium oxide film with a coverage of 90% or more, preferably 95% or more. A film with a coverage of 90% or more is called a dense film, and the coverage can be determined by image analysis from scanning probe microscopy photographs. Furthermore, it is preferable to have a state with minimal overlap of the thin-film titanium oxide particles or thin-film titanium-metal composite oxide particles; specifically, a film formed locally with a thickness of one particle without particle overlap, and the remaining portion formed with a thickness of at most two to three overlapping particles, forming a monolayer film. More preferably, it is a dense monolayer film with the same degree of density as a dense monolayer film produced by the Langmuir-Blodgett method. The absorbance of the titanium oxide film is measured, and by comparing it with the theoretical absorbance of the titanium oxide film, it can be confirmed that it is a monolayer film. Specifically, in this specification, a film exhibiting an absorbance of 80% to 120%, preferably 90% to 110%, relative to the theoretical absorbance (0.05) of a single-layer film of sheet-like titanium dioxide is defined as a single-layer film. In the case of such a dense single-layer film of sheet-like titanium dioxide, it is a transparent film with no absorption in the visible light region, and has an absorption peak in the ultraviolet-visible absorption spectrum in the wavelength range of 250 nm to 280 nm, and no absorption peak in the wavelength range of 300 nm to 800 nm. In the case of a dense single-layer film of sheet-like titanium-metal composite oxide, it is a film with absorption peaks in both the wavelength range of 250 nm to 280 nm and the wavelength range of 300 nm to 800 nm in the ultraviolet-visible absorption spectrum. When the blocking film 4 is a single-layer film of sheet-like titanium dioxide, its thickness can be appropriately set according to the thickness of the sheet-like titanium dioxide particles, for example, it can be set to 1 nm or more and 2 nm or less.

[0038] The blocking film 4 is preferably a laminated film formed by stacking the single-layer films. The laminated film is a multi-layered film formed by stacking single-layer films. Since the sheet-like titanium oxide particles or sheet-like titanium-metal composite oxide particles are oriented in each single-layer film, the properties of the single-layer film are maintained. Furthermore, the multi-layered structure, with its numerous sheet-like titanium oxide particles or sheet-like titanium-metal composite oxide particles, further enhances the characteristics of these particles. Specifically, if it is a laminated film, it can more effectively suppress the oxidation of the copper film (copper wiring) surface compared to a single-layer film. Each layer of the laminated film is preferably the dense single-layer titanium oxide film. Specifically, a transparent film that does not absorb in the visible light region and has an absorption peak in the ultraviolet-visible absorption spectrum in the wavelength range of 250 nm to 280 nm, and no absorption peak in the wavelength range of 300 nm to 800 nm, is preferred. The thickness of the laminated film can be appropriately adjusted, for example, by the number of laminations, and can be set to 1 nm or more and 50 nm or less, preferably 2 nm or more and 40 nm or less. When the thickness of the laminated film is 2 nm or more, the oxidation of the surface of the copper film (copper wiring) can be suppressed more effectively. When the thickness of the laminated film is 40 nm or less, the peelability of the barrier film 4 using dry etching can be further improved.

[0039] The insulating film 5 is provided to prevent short circuits between copper wirings 3 or multiple layers of wiring. As the insulating film 5, an inorganic film such as silicon dioxide or an organic film formed from a curable resin composition can be used.

[0040] There are no particular limitations on the curable resin composition, but from the viewpoint of excellent heat resistance and mechanical properties, a curable resin composition comprising a polyimide-based resin or a polybenzoxazole-based resin is preferred. Among these, a positive photosensitive resin composition that can improve the properties of the cured material is preferred. Examples of positive photosensitive insulating resin compositions include those described in Japanese Patent No. 4853155 and Japanese Patent No. 4692219. The positive photosensitive resin composition may also contain other additives such as phenolic compounds, crosslinking agents, crosslinking aids, crosslinking microparticles, bonding agents, solvents, sensitizers, and leveling agents, as needed.

[0041] The insulating film 5, formed from a positive photosensitive resin composition, is formed by curing the positive photosensitive resin composition. Therefore, it exhibits excellent resolution, thermal shock resistance, adhesion, and electrical insulation, and its shape change before and after the heating process is minimal. Thus, it is particularly suitable for use as an interlayer insulating film or planarization film for circuit boards.

[0042] As a method for forming the insulating film 5, for example, a positive photosensitive resin composition is coated onto a substrate 2, dried, and the solvent or the like is evaporated to form a coating film. Subsequently, the desired mask pattern is exposed, and development is performed using an alkaline developer to dissolve and remove the exposed portion, thereby obtaining the desired pattern. Furthermore, in order to reveal the properties of the insulating film, a heat treatment is performed after development, thereby forming the insulating film.

[0043] <Method for Manufacturing Wiring Board (I)>

[0044] The method (I) for manufacturing the wiring substrate is the method for manufacturing the wiring substrate described above. The method (I) for manufacturing the wiring substrate includes a step of directly or indirectly coating a composition for forming a barrier film on a substrate having copper wiring (hereinafter also referred to as "coating step (I)").

[0045] The manufacturing method of the wiring substrate may also include a process of heating or exposing the coating film formed by the coating process (hereinafter also referred to as the "film formation process").

[0046] [Coating Process (I)]

[0047] In this process, a barrier film forming composition is applied directly or indirectly to a substrate having copper wiring. The substrate having copper wiring has been described in the section on "Wire Wiring Substrate". The barrier film forming composition will be described later. The solvent is removed from the coating formed in this process, thereby forming the barrier film.

[0048] Examples of indirectly applying a barrier film forming composition to a substrate having copper wiring include: applying the barrier film forming composition to the insulating film; and applying the barrier film forming composition to a base coat formed to ensure adhesion between the substrate or insulating film and the barrier film. An example of the method for forming the insulating film is described in the section on "Wiring Substrate". Examples of the base coat include, for example, the polymer film described in the section on "Method for Manufacturing Wiring Substrate (II)" described later.

[0049] There are no particular limitations on the coating method. Examples include: spin coating, spray coating, roller coating, dip coating, flow coating, doctor blade coating, electrostatic coating, bar coating, mold coating, brush coating, and droplet coating.

[0050] This process can be performed once or multiple times. When performed once, a single-layer film of thin-film titanium dioxide is formed. When performed multiple times, a laminate of the single-layer film is formed. There is no particular limitation on the number of times this process is performed multiple times; for example, it can be performed more than 2 times and less than 50 times. When performed less than 40 times, a barrier film with high peelability obtained using dry etching is formed.

[0051] Furthermore, if the coating is performed in a single coating process with a film thickness of 0.1 nm or more and 2 nm or less, the flake-shaped titanium oxide particles are regularly arranged, thus forming a highly transparent barrier film.

[0052] [Film Forming Process]

[0053] In this process, the coating film formed by the coating process is heated or exposed to light. Including this process promotes the removal of solvent from the coating film and allows for efficient formation of a barrier film.

[0054] The coating can be heated at a temperature of 5°C or higher and 500°C or lower. The upper limit of the heating temperature is preferably 200°C, more preferably 150°C, and even more preferably 100°C. The lower limit of the heating temperature is preferably room temperature. Alternatively, film formation can be performed while maintaining a humidity level of approximately 50% to 100%, preferably approximately 60% to 95%. By appropriately setting the concentration of flake-like titanium dioxide in the barrier film forming composition, the film formation temperature, and other film formation conditions, and by appropriately controlling the film formation rate and the evaporation rate of the organic solvent, a barrier film with a high coverage rate of flake-like titanium dioxide particles or flake-like titanium-metal composite oxide on the substrate can be formed.

[0055] Exposure of the coating can be performed, for example, by irradiating it with light of a wavelength having energy above the band gap of titanium dioxide. This is a film formation method utilizing the photocatalytic ability of titanium dioxide.

[0056] <Method for Manufacturing Wiring Board (II)>

[0057] The method (II) for manufacturing the wiring substrate is the method for manufacturing the wiring substrate described above. The method (II) for manufacturing the wiring substrate includes: a step of directly or indirectly forming a polymer film on a substrate having copper wiring and coating a barrier film forming composition onto the polymer film (hereinafter also referred to as "coating step (II)"); and a step of removing the polymer film (hereinafter also referred to as "removal step").

[0058] [Coating Process (II)]

[0059] In this process, a polymer film is first formed directly or indirectly on a substrate having copper wiring. The substrate having copper wiring has been described in the section on "Wiring Substrate".

[0060] As an example of indirectly forming a polymer film on a substrate having copper wiring, one can include coating the insulating film with a barrier film forming composition. An example of the method for forming the insulating film is described in the section on <wiring substrate>.

[0061] Examples of methods for forming polymer films include coating a polymer solution of a cationic polymer such as poly(ethyleneimine), polydiallyl dimethylammonium chloride, or polyallylamine hydrochloride onto a substrate.

[0062] The thickness of the formed polymer film can be appropriately set, for example, it can be set to be above 0.5 nm and below 20 nm.

[0063] In this process, a barrier film forming composition is then coated onto the polymer film. The barrier film forming composition will be described later.

[0064] There are no particular limitations on the coating method for the composition used to form the barrier film, and examples include: spin coating, spray coating, roller coating, dip coating, flow coating, doctor blade coating, electrostatic coating, bar coating, mold coating, brush coating, and droplet application.

[0065] This process can be performed once or multiple times. When performed once, a single-layer film of thin-film titanium dioxide is formed. When performed multiple times, a laminate of the single-layer film is formed. There is no particular limitation on the number of times this process is performed multiple times; for example, it can be performed more than 2 times and less than 50 times. When performed less than 40 times, a barrier film with high peelability obtained using dry etching is formed.

[0066] Furthermore, when this process is performed multiple times, if the coating is applied in a single coating process to achieve a film thickness of 0.1 nm or more and 2 nm or less, the flake-shaped titanium oxide particles or flake-shaped titanium-metal composite oxide particles are regularly arranged, thus forming a barrier film with high transparency.

[0067] In this process, polymer films and barrier films are alternately stacked, thus corresponding to a method known as the alternating adsorption stacking method. In this method, since sheet-like titanium oxide particles or sheet-like titanium-metal composite oxide particles are adsorbed onto the polymer layer, it has the advantage of easily forming a thick barrier film.

[0068] [Removal Process]

[0069] In this process, the polymer film is removed. This process removes the polymer film, forming a barrier layer.

[0070] There are no particular limitations on the methods for removing polymer films. Examples include methods involving heating and methods involving exposure. For example, methods involving heating at 400°C can be used for removal. For example, methods involving exposure can include irradiation with ultraviolet light (at a wavelength of 300 nm or less, intensity: 1 mW / cm²) for 12 hours. 2 The method.

[0071] <Composition for Barrier Film Formation>

[0072] The barrier film forming composition is used to manufacture the wiring substrate described above. In other words, the barrier film forming composition is used to manufacture a wiring substrate in which a barrier film is directly or indirectly included on a substrate having copper wiring, and the barrier film contains flake-shaped titanium oxide or flake-shaped titanium-metal composite oxide. Furthermore, the barrier film forming composition is used in the coating step of the wiring substrate manufacturing method described above.

[0073] In one embodiment, the composition for forming the barrier film contains: flake-shaped titanium dioxide or flake-shaped titanate or its salt (hereinafter also referred to as "flake-shaped titanium dioxide compound") and a solvent.

[0074] Flake-shaped titanium dioxide compounds readily swell with water, and the layers may peel off and disperse depending on the situation. Examples of flake-shaped titanium dioxide compounds include: flake-shaped titanium dioxide, flake-shaped titanate, or flake-shaped titanate.

[0075] Thin-film titanates are considered to have a structure consisting of layered TiO2 crystals and cations present between the layers (interlayer ions), and also include structures formed by the substitution of a portion of Ti in the TiO2 crystals by other cations or lattice defects. For example, Japanese Patent No. 3062497 discloses the structural formula and manufacturing method of thin-film titanates.

[0076] According to Japanese Patent No. 3062497, sheet-like titanates can be obtained, for example, by the following method: using a metal that forms interlayer ions, a cation that replaces a portion of Ti within the crystal, and an oxide of Ti or a compound that becomes the oxide by heating as raw materials, and using an alkali metal or alkaline earth metal halide or sulfate as a flux, the mixture prepared by mixing at a flux / raw material mass ratio of 0.2 to 1.3 is heated and calcined at 700°C to 1200°C.

[0077] Examples of metals that form interlayer ions include alkali metals such as potassium, rubidium, and cesium. Additionally, metals with valences of 1 to 3 different from the aforementioned metals can be listed as cations that replace a portion of the Ti within the crystal. Examples include metals selected from alkaline earth metals, Li, Zn, Cu, Fe, Al, Ga, Mn, and Ni.

[0078] Examples of sheet-like titanates include those obtained by acting a basic organic compound on the sheet-like titanate, wherein the interlayer ions are organic cations. As a basic organic compound, a basic organic compound with interlayer swelling effect is preferred, such as: alkylamines and their salts such as methylamine, ethylamine, propylamine, diethylamine, triethylamine, butylamine, dodecylamine, stearylamine, dipentylamine, dioctylamine, trioctylamine, 2-ethylhexylamine, ethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, 2-amino-2-methyl-1-propanol, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, dodecyltrimethylammonium salt, cetyltrimethylammonium salt, stearyltrimethylammonium salt, benzyltributylammonium salt, 3-methoxypropylamine, 3-ethoxypropylamine, polyethyleneimine, polydiallyldimethylammonium chloride, dodecyltributylphosphonium salt, octadecyltributylphosphonium salt, etc.

[0079] The effect of alkaline compounds can be achieved by adding alkaline compounds to a suspension formed by dispersing flake-shaped titanic acid in an aqueous medium under stirring.

[0080] Examples of sheet-like titanates include those formed by treating the sheet-like titanate with acid or warm water and replacing interlayer ions and / or cations that have replaced a portion of the Ti in the TiO2 crystals with hydrogen and / or hydrated hydrogen ions.

[0081] Acid treatment can be carried out, for example, by adding an acid to an aqueous dispersion of flake titanate under stirring. Examples of acids include inorganic or organic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and boric acid. Warm water treatment can be carried out, for example, by dispersing the flake titanate in warm water above 60°C and stirring.

[0082] Flake-shaped titanium dioxide can be obtained by heating a titanium dioxide sol obtained by acting an alkaline organic compound on the flake-shaped titanium dioxide as described above, and then removing the alkali and water, as described, for example, in Japanese Patent No. 2979132. The flake-shaped titanium dioxide is a layered crystal containing titanium dioxide. By acting on it with an alkaline organic compound that has an interlayer swelling effect, the interlayers swell or peel off, and then it is dried and re-coalesced to obtain a titanium dioxide layer with a thickness of less than 1 nm. If amines or water are sandwiched between the layers, it is believed that if it is heated, the water and amines will detach from the interlayers at 100°C to 350°C, and the layers will be peeled off to obtain the flake-shaped titanium dioxide.

[0083] If the flake-shaped titanium dioxide particles contain the organic cations described later, the flake-shaped titanium dioxide particles are easily dispersed due to the charge repulsion between the organic cations, which is therefore preferable. However, if the content of organic cations is too high, it may conversely lead to the aggregation of the flake-shaped titanium dioxide particles. Therefore, the content of organic cations is preferably in the range of 0.05 equivalents to 3 equivalents relative to the titanium (Ti) contained in the flake-shaped titanium dioxide, more preferably in the range of 0.1 equivalents to 3 equivalents, and even more preferably in the range of 0.9 equivalents to 1.5 equivalents. As organic cations, quaternary ammonium ions are preferred, and more preferably quaternary ammonium ions such as tetrabutylammonium ions with a total carbon number of 9 or more. If quaternary ammonium ions with a total carbon number of 9 or more are contained, they can also be dispersed in many organic solvents. In addition, from the viewpoints of dispersibility in organic solvents and affinity to resins, existing organic compounds such as surfactants and coupling agents or inorganic compounds such as silica and alumina can be coated on the surface of the flake-shaped titanium dioxide particles.

[0084] The content of the flake-shaped titanium dioxide particles in the composition for forming the barrier film can be appropriately adjusted. In terms of TiO2, it is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, more preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more. If the content is too high, the volume that each flake-shaped titanium dioxide particle can occupy becomes smaller, making it prone to aggregation and sedimentation. Therefore, in terms of TiO2, it is preferably 10% by mass or less, more preferably 1.0% by mass or less. Depending on the situation, in terms of TiO2, it is more preferably 0.001% to 10% by mass, more preferably 0.01% to 10% by mass, more preferably 0.02% to 10% by mass, even more preferably 0.05% to 10% by mass, even more preferably 0.05% to 1.0% by mass, and even more preferably 0.1% to 1.0% by mass.

[0085] As an organic solvent, it can be appropriately selected according to the application. If the organic solvent has a dielectric constant of 5 or higher, the flake-shaped titanium dioxide particles are easily dispersed. Therefore, it is preferred, and more preferably, an organic solvent with a dielectric constant of 10 or higher. As such an organic solvent, it is more preferably at least one selected from the group consisting of acetonitrile (dielectric constant 37, boiling point 82°C), methanol (dielectric constant 33, boiling point 65°C), dimethyl sulfoxide (dielectric constant 47, boiling point 189°C), ethanol (dielectric constant 24, boiling point 78.3°C), 2-propanol (dielectric constant 18, boiling point 82.5°C), γ-butyrolactone (dielectric constant 39, boiling point 205°C), N,N-dimethylformamide (dielectric constant 38, boiling point 153°C), methyl ethyl ketone (dielectric constant 18.5, boiling point 80°C), 1-butanol (dielectric constant 17.8, boiling point 118°C), and formamide (dielectric constant 109, boiling point 210°C).

[0086] The barrier film forming composition is almost free of water, preferably with a water content of 10% by mass or less, more preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less. The barrier film forming composition may also include, within a range that does not impair the effects of the present invention, various additives and fillers such as resin binders, dispersants, surface conditioners (leveling agents, wetting modifiers), pH adjusters, defoamers, emulsifiers, colorants, extenders, mildew inhibitors, hardening aids, and thickeners as a third component.

[0087] The composition for forming the barrier film is manufactured by: (1) centrifuging an aqueous dispersion of flake-shaped titanium dioxide particles containing organic cations, mixing the obtained precipitate with an organic solvent, and dispersing it; or (2) freeze-drying an aqueous dispersion of flake-shaped titanium dioxide particles containing organic cations, then mixing the obtained freeze-dried material with an organic solvent and dispersing it; or (3) removing water from an aqueous dispersion of flake-shaped titanium dioxide particles containing organic cations using an evaporator, mixing the obtained dried material with an organic solvent, and dispersing it.

[0088] When manufacturing the aqueous dispersion of the thin-film titanium dioxide particles containing organic cations, the methods described in, for example, the manual WO99 / 11574 can be used. Specifically, the WO99 / 11574 manual discloses the following: (1) Synthesizing layered titanate metal salts such as cesium titanate, potassium lithium titanate, and magnesium potassium titanate, and then suspending the obtained layered titanate metal salts in an aqueous solution, and then adding acids such as hydrochloric acid, sulfuric acid, and nitric acid to extract metal ions, thus obtaining titanate with a layered structure; (2) Suspending the layered titanate produced by the method described in (1) in a medium solution, and then adding alkaline compounds such as amine compounds and ammonium compounds as organic cation sources, thus obtaining sheet-like titanium oxide particles with a structure in which the interlayers are swollen and containing organic cations; (3) Vibrating the sheet-like titanium oxide particles after the interlayers are swollen by the method described in (2), thereby peeling off the interlayers, thus obtaining sheet-like titanium oxide nanosheets, and suitable use of an aqueous dispersion containing the sheet-like titanium oxide particles in (2) and an aqueous dispersion containing the sheet-like titanium oxide nanosheets in (3) with the interlayers peeled off.

[0089] Specifically, the titanate metal salt produced in step (1) is preferably a mixed alkali metal titanate salt produced, for example, in the following manner: Alkali metal oxides M₂O and M'₂O (M and M' being different alkali metals) or compounds that decompose into M₂O and M'₂O respectively by heating, are mixed with titanium dioxide or compounds that produce titanium dioxide by heating, preferably in a ratio of 3 / 1 / 5 to 3 / 1 / 11 based on the molar ratio of M / M' / Ti, and calcined at a temperature of 500°C to 1100°C, and more preferably 600°C to 900°C. This temperature range is preferred to ensure sufficient reaction, reduce the residual amount of the raw material composition, and suppress the formation of substances with other compositions. The obtained mixed alkali metal titanate salt has Ti as its main framework. 4+ A portion of the site is formed by the replacement of alkali metal ions different from the alkali metal in the interlayer, with the composition M. x [M' x / 3 Ti 2-x / 3The compound is a layered structure with orthorhombic crystals (lepidocrocite type crystal structure) represented by O4 (where M and M' are different alkali metals, and x is 0.50 to 1.0). The alkali metal ions represented by M and M' in the substance are active, thus undergoing exchange reactions with other cations or introduction due to intercalation of organic matter. Therefore, when contacted with an acidic aqueous solution, the alkali metal ions in the interlayer (M) and the main framework (M') are exchanged for hydrogen ions (existing as hydrated hydrogen ions) in a short time, resulting in a thin-film titanium dioxide dispersion with good efficiency and low production cost in industrial production. The x in the composition formula can be controlled by changing the mixing ratio of the starting materials. Furthermore, to obtain a homogeneous and single-phase compound, it is preferable to thoroughly mix the raw material powders during the synthesis process, preferably by grinding and mixing the powders using an automatic mortar and pestle. In addition, by appropriately selecting the calcination temperature when manufacturing layered titanate metal salts, or by using a so-called fluxing method that adds flux during calcination, the particle size of layered titanate metal salts can be appropriately adjusted, thereby allowing for appropriate control of the particle size of sheet-like titanium oxide.

[0090] Preferably, in step (2), an alkaline compound serving as an organic cation source, preferably in the range of 0.05 to 3 neutralizing equivalents relative to the hydrogen (H) contained in the layered titanate, is mixed in a medium solution to remove the hydrogen contained in the layered titanate and insert the alkaline compound into the interlayer. Then, as described in (3), the layers are peeled off to produce sheet-like titanium oxide particles. If the amount of alkaline compound is less than the range described, hydrogen ions will not be sufficiently removed; if it is more than the range described, swelling will occur, making interlayer peeling difficult. A more preferred amount is 0.1 to 3 neutralizing equivalents, and more preferably 0.9 to 1.5 neutralizing equivalents. The amount of alkaline compound is preferably in the range of 0.05 to 3 equivalents relative to the titanium (Ti) contained in the layered titanate, more preferably in the range of 0.1 to 3 equivalents, and more preferably 0.9 to 1.5 equivalents. The amount of the alkaline compound preferably satisfies both the preferred range relative to hydrogen (H) and the preferred range relative to titanium (Ti). A portion of this alkaline compound is contained in the sheet-like titanium oxide as an organic cation, preferably contained on the particle surface.

[0091] Examples of alkaline compounds include: (1) quaternary ammonium hydroxide compounds (tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc.); (2) alkylamine compounds (propylamine, diethylamine, etc.); (3) alkanolamine compounds (ethanolamine, aminomethylpropanol, etc.). Among these, quaternary ammonium hydroxide compounds are preferred due to their excellent reactivity. If quaternary ammonium hydroxide compounds with a total carbon number of 9 or more, such as tetrabutylammonium hydroxide compounds, are used, they also function effectively as dispersants for flake-shaped titanium dioxide particles when preparing organic solvent dispersions, and are therefore more preferred. Examples of media used in step (2) include: organic solvents such as water or alcohol, or mixtures thereof. Industrially, an aqueous media mainly composed of water is preferred. There is no particular limitation on the order in which layered titanic acid or alkaline compounds are added to the media. For example, layered titanic acid and alkaline compounds can be added to water, stirred, and mixed. Alternatively, an alkaline compound can be added to a slurry formed by dispersing layered titanic acid in water, or the layered titanic acid can be added to an aqueous solution of an alkaline compound. Then, if stirring continues, the layers of the layered titanic acid are peeled off, resulting in sheet-like titanium oxide particles. There are no particular restrictions on the reaction temperature at this time; it is preferable to carry out the reaction at room temperature for 1 to 20 days to prevent the layered titanic acid from decomposing. Furthermore, to further improve the degree of interlayer peeling, the container containing the solution can be vibrated as described in step (3). Through this vibration, nanosheets with a length and width of approximately 0.1 μm to 30 μm and a thickness of approximately 0.5 nm to 10 nm, preferably approximately 0.5 nm to 2 nm, and more preferably approximately 0.5 nm to 1 nm, can be manufactured. During vibration, a vibrator, coating regulator, oscillator, etc., can be used.

[0092] Thin-film titanium dioxide particles are preferably composed of Ti 2-x / 3 O4 (4x / 3)- (where x in the formula ranges from 0.57 to 1.0), specifically Ti 1.81 O4 0.76- ~Ti 1.67 O4 1.33- This indicates that in the thin-film titanium oxide particles, TiO6 octahedra are interlocked through shared edges to form a two-dimensional framework structure, thereby enabling Ti... 4+ 9.5% to 17% of the particles become defects, thus forming a structure with a large negative charge in the thin, sheet-like particles.

[0093] Next, the dispersion of the flake-shaped titanium dioxide particles containing organic cations, preferably an aqueous dispersion, is centrifuged to separate the precipitate from the solvent. A conventional centrifuge can be used for centrifugation. To adjust to the desired water content, centrifugation can be repeated two or more times. The separated precipitate is mixed with and dispersed in an organic solvent to obtain an organic solvent dispersion. When dispersing the flake-shaped titanium dioxide particles in the organic solvent, conventional mixers, colloid mills, ball mills, bead mills, vibrators, coating conditioners, oscillators, etc., can be used. At this time, the third component can be added.

[0094] Alternatively, a dispersion, preferably an aqueous dispersion, of flake-shaped titanium dioxide particles containing organic cations can be freeze-dried to obtain a freeze-dried product. A conventional freeze dryer can be used for freeze-drying. To adjust the obtained freeze-dried product to the desired moisture content, ice can be further sublimated under vacuum. Next, the obtained freeze-dried product is mixed with an organic solvent and dispersed. When dispersing the flake-shaped titanium dioxide particles, the same conventional mixers, colloid mills, ball mills, bead mills, dispersers, vibrators, coating conditioners, oscillators, etc., as described above can be used; at this time, the third component can be added.

[0095] In another embodiment, the composition for forming the barrier film contains: a sheet-like titanium-metal composite oxide or a sheet-like titanium-metal acid or its salt (hereinafter also referred to as "sheet-like titanium-metal compound") and a solvent.

[0096] Examples of metals that can be used in sheet-like titanium-metal composite oxides include iron, cobalt, nickel, manganese, or combinations thereof. Among these, iron is preferred. Furthermore, in this specification, when the metal is iron, the sheet-like titanium-iron composite oxide is sometimes referred to as "sheet-like titanium-iron oxide".

[0097] When the composition for forming the barrier film contains flake-shaped titanium dioxide, it exhibits higher barrier properties than when it contains flake-shaped titanium dioxide. That is, fewer coating layers are required compared to flake-shaped titanium dioxide, and even with a thin film thickness, sufficient wiring oxidation prevention effect can be obtained.

[0098] The following explanation will be based on the case where the metal is iron.

[0099] Flake-shaped titanium-iron compounds readily swell with water, and the layers may peel off and disperse depending on the situation. Examples of flake-shaped titanium-iron compounds include: flake-shaped ferrotitanium oxide, flake-shaped ferric titanate, or flake-shaped ferric titanate.

[0100] Thin-film titanates have the same crystal structure as thin-film titanates, with a portion of the Ti in the layered TiO2 crystals replaced by Fe. Examples of metals that form cations (interlayer ions) that contribute to the formation of interlayer ions include alkali metals such as potassium, rubidium, and cesium.

[0101] Examples of sheet-like titanates include those obtained by acting a basic organic compound on the sheet-like titanate described below, wherein the interlayer ions are organic cations. Examples of basic organic compounds that can act on sheet-like titanates include those exemplified above.

[0102] The effect of alkaline organic compounds can be achieved by adding the alkaline compound to a suspension formed by dispersing flake-shaped titanium ferric acid in an aqueous medium under stirring.

[0103] Examples of sheet-like titanium ferrites include those obtained by treating the sheet-like titanium ferrites with acid or warm water, and replacing interlayer ions and / or cations that have replaced a portion of the Ti in the TiO2 crystals with hydrogen and / or hydrated hydrogen ions.

[0104] Acid treatment can be applied using the same methods as those used for the aqueous dispersion of the flake titanate.

[0105] Flake-shaped titanium ferric oxide can be obtained by heating a sol obtained by acting an alkaline organic compound on the flake-shaped titanium ferric oxide, similar to flake-shaped titanium oxide, and then removing the alkali and water.

[0106] The content of organic cations contained in the flake-shaped titanium iron oxide particles is preferably in the range of 0.05 equivalents to 3 equivalents relative to the hydrogen (H) contained in the flake-shaped titanium iron oxide, more preferably in the range of 0.1 equivalents to 3 equivalents, and even more preferably in the range of 0.9 equivalents to 1.5 equivalents. Quaternary ammonium ions are preferred as organic cations, and more preferably quaternary ammonium ions such as tetrabutylammonium ions with a total carbon number of 9 or more. If quaternary ammonium ions with a total carbon number of 9 or more are contained, they can also be dispersed in many organic solvents. Furthermore, from the viewpoint of dispersibility in organic solvents and affinity to resins, existing organic compounds such as surfactants and coupling agents or inorganic compounds such as silica and alumina can be coated onto the surface of the flake-shaped titanium iron oxide particles.

[0107] The content of the flake-shaped titanium iron oxide particles in the composition for forming the barrier film, calculated in terms of TiO2, is more preferably 0.001% to 10% by mass, more preferably 0.01% to 10% by mass, more preferably 0.02% to 10% by mass, even more preferably 0.05% to 10% by mass, even more preferably 0.05% to 1.0% by mass, and particularly preferably 0.1% to 1.0% by mass.

[0108] In manufacturing the aqueous dispersion of the thin-film titanium iron oxide particles containing organic cations, (4) layered titanium iron oxide metal salts such as lithium potassium titanate and potassium magnesium titanate are synthesized. Then, the obtained layered titanium iron oxide metal salts are suspended in an aqueous solvent. After that, acids such as hydrochloric acid, sulfuric acid, and nitric acid are added to extract metal ions, and titanium iron oxide with a layered structure is obtained. (5) The layered titanium iron oxide produced by the method described in (4) is suspended in a medium solution. Then, alkaline compounds such as amine compounds and ammonium compounds as organic cation sources are added, and thin-film titanium iron oxide particles with a structure in which the interlayers are swollen and containing organic cations are obtained. (6) The thin-film titanium iron oxide particles in which the interlayers are swollen by the method described in (5) are vibrated, etc., thereby peeling off the interlayers, and thin-film titanium iron oxide particles are obtained.

[0109] As the titanate metal salt produced in the process described in (4), specifically, it is preferably a mixed alkali metal titanate salt produced, for example, in the following manner: Alkali metal oxides M2O and M'2O (M and M' are different alkali metals) or compounds that decompose into M2O and M'2O respectively by heating, titanium dioxide or compounds that produce titanium dioxide by heating, and iron oxide (III) or compounds that produce iron oxide (III) by heating are preferably mixed in a ratio of 3 / 1 / 13 / 0 to 3 / 0 / 9 / 3 based on the molar ratio of M / M' / Ti / Fe, and calcined at a temperature of 500°C to 1100°C, and more preferably 600°C to 1000°C. This temperature range is preferred in order to ensure sufficient reaction, reduce the residual amount of the raw material composition, and suppress the formation of substances with other compositions. The obtained mixed alkali metal titanate salt has Ti in its main framework. 4+ A portion of the site is affected by alkali metal ions or Fe, which are different from the alkali metal in the interlayer. 3+ The substitution-formulated M x [M' (x-y) / 3 Ti (6-x-2y) / 3 Fe yThe compound is a layered structure (ferrihydride-type crystal structure) with orthorhombic crystals, represented by O4 (where M and M' are different alkali metals, x is 0.50–1.0, and y is 0–1.0). The alkali metal ions represented by M and M' in this substance are active, thus undergoing exchange reactions with other cations or introduction due to intercalation of organic matter. Therefore, when contacted with an acidic aqueous solution, the alkali metal ions in the interlayer (M) and the main framework (M') are exchanged for hydrogen ions (existing as hydrated hydrogen ions) in a short time, resulting in a thin-film titanium-iron oxide dispersion with good efficiency and low production cost in industrial production. The x and y in the composition formula can be controlled by changing the mixing ratio of the starting materials. Furthermore, to obtain a homogeneous and single-phase compound, it is preferable to thoroughly mix the raw material powders during the synthesis process, preferably by grinding and mixing the powders using an automatic mortar and pestle. In addition, by appropriately selecting the calcination temperature when manufacturing layered titanium ferrite metal salts, or by using a so-called fluxing method that adds flux during calcination, the particle size of layered titanium ferrite metal salts can be appropriately adjusted, thereby allowing for appropriate control of the particle size of sheet-like titanium ferrooxide.

[0110] Preferably, in step (5), an alkaline compound serving as an organic cation source, preferably in the range of 0.05 to 3 neutralizing equivalents relative to the hydrogen (H) contained in the layered ferrotitanium oxide, is mixed in a medium solution to remove the hydrogen contained in the layered ferrotitanium oxide and insert the alkaline compound into the interlayer. Then, as described in (6), the layers are peeled off to produce sheet-like ferrotitanium oxide particles. If the amount of alkaline compound is less than the range described, hydrogen ions will not be sufficiently removed; if it is more than the range described, swelling will occur, making interlayer peeling difficult. A more preferred amount is 0.1 to 3 neutralizing equivalents, and more preferably 0.9 to 1.5 neutralizing equivalents. The amount of alkaline compound is preferably in the range of 0.05 to 3 equivalents relative to the titanium (Ti) contained in the layered ferrotitanium oxide, more preferably in the range of 0.1 to 3 equivalents, and more preferably 0.9 to 1.5 equivalents. The amount of the alkaline compound preferably satisfies both the preferred range relative to hydrogen (H) and the preferred range relative to titanium (Ti). A portion of this alkaline compound is contained in the sheet-like ferrotitanium oxide as an organic cation, preferably contained on the particle surface.

[0111] The thin-film titanium iron oxide particles are preferably composed of the formula [Ti (6-x-2y) / 3 Fe y O4] (4x-y) / 3- (where x ranges from 0.57 to 1.0 and y ranges from 0 to 0.80), specifically Ti >1.73 Fe >0 O4 <1.17- ~Ti 1.20 Fe 0.8O4 0.8- This indicates that in the thin-film titanium-iron oxide particles, TiO6 octahedra are interlocked through shared edges to form a two-dimensional framework structure, thereby enabling Ti... 4+ 0%–40% of the site is replaced with Fe. 4+ In addition, Ti 4+ 0%–17% of the sites become defects, thus forming a structure with large negative charges in thin, lamellar particles. With Fe… 4+ For Ti 4+ Bit substitution, Ti 4+ With the reduction of defects at position y=0.8, theoretically, it becomes a state without Ti. 4+ Crystal structure with defects at position.

[0112] The crystalline lattice of the sheet-like titanium oxide particles has fewer defects than that of sheet-like titanium oxide particles, thus improving the barrier properties in both single-particle and stacked states. Specifically, the barrier film composed of sheet-like titanium oxide particles exhibits equivalent barrier properties in thinner stacked structures compared to the barrier film composed of sheet-like titanium oxide particles.

[0113] The flake-shaped titanium oxide iron particles exhibit relatively high barrier properties compared to flake-shaped titanium oxide particles, thus reducing the number of coating operations required to form the barrier film, for example, when forming a laminated structure using spin coating.

[0114] Example

[0115] The present invention will now be described in detail based on specific embodiments. However, the present invention is not limited to these embodiments.

[0116] <Synthesis of flake-shaped titanium dioxide>

[0117] Layered titanium oxide (K 0.8 Ti 1.73 Li 0.27 Using O4 as a starting material, sheet-like titanium dioxide (TiO2) is synthesized through the following method. 0.87 O2).

[0118] Layered titanium oxide (K) as a starting material 0.8 Ti 1.73 Li 0.27 TiO2 was synthesized as follows: Potassium carbonate (K2CO3), lithium carbonate (Li2CO3), and titanium dioxide (TiO2) were mixed in a molar ratio of 3 / 1 / 13 and thoroughly pulverized. The mixture was then placed in a platinum crucible and temporarily calcined at 800°C for one hour. Subsequently, the temporarily calcined raw material powder was pulverized and mixed again. Then, the pulverized and mixed raw material powder was placed in a platinum crucible and calcined at 1,000°C for 20 hours to obtain layered titanium oxide (K2CO3). 0.8 Ti 1.73Li 0.27 O4).

[0119] Add 50 cm of hydrochloric acid with a concentration of 1 equivalent to 1 g of the obtained layered titanium oxide. 3 The reaction was carried out at room temperature with mechanical stirring for 24 hours. After the 24-hour reaction, stirring was stopped, and the mixture was allowed to stand for 3 hours. The supernatant was then removed by decantation. Subsequently, an amount of hydrochloric acid with a concentration of 1 equivalent to the amount removed by decantation was added, and the 24-hour reaction and supernatant removal were repeated twice. The mixture was then filtered, washed with water, and dried to obtain a hydrogen ion exchanger (H2O). 1.07 Ti 1.73 Powdered O4·H2O was then added. Subsequently, a hydrogen ion exchanger was mixed at a ratio of 4 g / L with the H+ ion in the hydrogen ion exchanger. + A solution containing 1 neutralized equivalent of tetrabutylammonium hydroxide was dissolved in an aqueous solution and reacted at room temperature with mechanical stirring for 7 days to obtain flake-like titanium dioxide (Ti). 0.87 Aqueous dispersion of O2 (sample 1).

[0120] <Synthesis of flake-shaped iron titanium oxide>

[0121] Layered titanium iron oxide (K 0.8 Ti 1.49 Li 0.14 Fe 0.37 Using O4 as a starting material, sheet-like titanium iron oxide (Ti) is synthesized through the following method. 1.49 Fe 0.37 O4).

[0122] Layered titanium-iron oxide (K) as a starting material 0.8 Ti 1.49 Li 0.14 Fe 0.37 (O4) is synthesized as follows: Potassium carbonate (K2CO3), lithium carbonate (Li2CO3), iron(III) oxide (Fe2O3), and titanium dioxide (TiO2) are mixed in a molar ratio of 6 / 1 / 3 / 21 and thoroughly pulverized. The mixture is then placed in a platinum crucible and temporarily calcined at 800°C for one hour. Subsequently, the temporarily calcined raw material powder is pulverized and mixed again. Then, the pulverized and mixed raw material powder is placed in a platinum crucible and calcined at 1,000°C for 20 hours to obtain layered titanium iron oxide (K4). 0.8 Ti 1.49 Li 0.14 Fe 0.37 O4).

[0123] Add 50 cm of hydrochloric acid with a concentration of 1 equivalent to 1 g of the obtained layered titanium iron oxide. 3 The reaction was carried out at room temperature with mechanical stirring for 24 hours. After the 24-hour reaction, stirring was stopped, and the mixture was allowed to stand for 3 hours. The supernatant was then removed by decantation. Subsequently, an amount of hydrochloric acid with a concentration of 1 equivalent to the amount removed by decantation was added, and the 24-hour reaction and supernatant removal were repeated twice. The mixture was then filtered, washed with water, and dried to obtain a hydrogen ion exchanger (H2O). 0.94 Ti 1.49 Fe 0.37 Powdered O4·H2O was then added. Subsequently, a hydrogen ion exchanger was mixed at a ratio of 4 g / L with the H+ ion in the hydrogen ion exchanger. + A solution containing 1 neutralized equivalent of tetrabutylammonium hydroxide was dissolved in an aqueous solution and reacted at room temperature with mechanical stirring for 7 days to obtain flake-like titanium iron oxide (Ti). 1.49 Fe 0.37 Aqueous dispersion of O4 (sample 2).

[0124] <Evaluation of substrate fabrication>

[0125] A curable resin composition (JSR's "WPR series") is coated onto a silicon substrate having copper wiring (wire width: 20 μm, wire spacing: 20 μm, wire height: 7 μm to 8 μm). The substrate is then heated at 110°C for 5 minutes using a hot plate to form a 10 μm thick coating on the copper wiring. Subsequently, the substrate is exposed to a desired mask pattern and developed using an alkaline developer to dissolve and remove the exposed areas, thereby forming the desired pattern. The coating is then cured in a convection oven at 200°C for 1 hour to form an insulating film, thus creating an evaluation substrate.

[0126] <Formation of the barrier membrane>

[0127] For the evaluation substrate described above, a barrier film is formed using the following method. The thickness of the barrier film is measured using an atomic force microscope (AFM; Bruker's Dimension FastScan).

[0128] [Examples 1 to Examples 7]

[0129] In Examples 1 to 7, the barrier film was formed by an alternating adsorption layering method.

[0130] (Preparation of Solution 1)

[0131] The sample 1 obtained in the "Synthesis of Flake Titanium Oxide" section was diluted with water to become 0.01% by mass of flake titanium oxide, and the pH was adjusted to 9 with nitric acid to prepare solution 1.

[0132] (Preparation of Solution 2)

[0133] Solution 2 was obtained by diluting the poly(ethyleneimine) solution (manufactured by Sigma-Aldrich, Mw: ~750,000, 50% by mass aqueous solution) with water to a concentration of 0.25% by mass and adjusting the pH to 9 with nitric acid.

[0134] (Formation of the barrier membrane)

[0135] The evaluation substrate prepared in the "Preparation of Evaluation Substrate" section is immersed in solution 1 for 5 minutes. Afterwards, it is rinsed with pure water and dried. Next, the evaluation substrate is immersed in solution 2 for 5 minutes. Afterwards, it is rinsed with pure water and dried. The above operations are repeated until the film thickness shown in Table 1 below is achieved. Then, it is irradiated with ultraviolet light (at a wavelength of 300 nm or less, intensity: 1 mW / cm²) for 12 hours. 2 This removes the resin layer formed by solution 2, thus forming a barrier film.

[0136] [Examples 8 to 11]

[0137] In Examples 8 to 11, the barrier film was formed by spin coating.

[0138] (Preparation of solution 3)

[0139] The poly(ethyleneimine) solution was diluted with propylene glycol monomethyl ether (PGME) to a concentration of 2.0% by mass to obtain solution 3.

[0140] (Preparation of solution 4)

[0141] For sample 1 obtained in the section "Synthesis of Flake-like Titanium Oxide", water was evaporated using an evaporator and dried using a vacuum dryer (60°C, approximately 12 hours) to obtain flake-like titanium oxide powder. Subsequently, γ-butyrolactone was added in a manner that resulted in titanium oxide nanosheets at 0.2% by mass to obtain solution 4.

[0142] Using the solution 3, the evaluation substrate 1 is coated with a spin coater (Mikasa MS-B150) at 1,500 rpm for 1 minute, and heated at 100°C for 10 minutes using a hot plate to form a primer film. Then, the solution 4 is coated using the spin coater. The coating operation of solution 4 is repeated until the film thickness is achieved as described in Table 1 below, forming a barrier film.

[0143] [Examples 12-14]

[0144] In Examples 12 to 14, the barrier film was formed by spin coating.

[0145] (Preparation of solution 5)

[0146] For sample 2 obtained in the section "Synthesis of Flake-shaped Ferrotitanium Oxide", water was evaporated using an evaporator and dried using a vacuum dryer (60°C, approximately 12 hours) to obtain flake-shaped ferrotitanium oxide powder. Subsequently, γ-butyrolactone was added in a manner that resulted in ferrotitanium oxide nanosheets at 0.2% by mass to obtain solution 5.

[0147] Using the solution 3, the evaluation substrate 1 is coated with the spin coater at 1,500 rpm for 1 minute, and heated at 100°C for 10 minutes using a heating plate to form a primer film. Then, the solution is coated using the spin coater. The coating operation of solution 5 is repeated until the film thickness is achieved as described in Table 1 below, forming a barrier film.

[0148] [Comparative Example 1]

[0149] In Comparative Example 1, as a control, a wiring substrate without a barrier film was used, namely the evaluation substrate prepared in the <Preparation of Evaluation Substrate> section.

[0150] [Comparative Example 2]

[0151] In Comparative Example 2, as a control, a titanium oxide film was formed by sputtering. Specifically, a 10 nm titanium oxide film was formed on the evaluation substrate prepared in the <Preparation of Evaluation Substrate> section by sputtering.

[0152] <Evaluation>

[0153] [Oxidation Test of Cu Wiring]

[0154] The wiring substrates obtained in Examples 1 to 14 and Comparative Examples 1 to 2 were heated at 200°C for 120 hours using a convection oven. After the treatment, the cross-section of the insulating layer and Cu wiring was exposed using a cross-section polisher (JEOL DATUM, Inc.'s "SM-09010"). The cross-section of the Cu wiring was then observed at 10,000x magnification using a scanning electron microscope (FEI Corporation's "Apreo S LoVac"). The degree of oxidation inhibition of the Cu wiring was evaluated by the thickness of the oxide film formed on the surface of the Cu wiring. Cases with an oxide film thickness of less than 10 nm were classified as "A" (extremely good); cases with an oxide film thickness exceeding 10 nm but less than 100 nm and a pore size in the Cu layer less than 200 nm were classified as "B" (good); cases with an oxide film thickness of 100 nm or more but less than 200 nm and a pore size in the Cu layer of 200 nm or more but less than 300 nm were classified as "C" (slightly good); and cases with an oxide film thickness of 200 nm or more and a pore size in the Cu layer of 300 nm or more were classified as "D" (poor). The results are shown in Table 1 below. Additionally, microscopic images are shown in... Figures 3-7 middle. Figure 3 These are microscope images of Example 1. Figure 4 These are microscope images of Example 4. Figure 5 This is a microscope photograph of Comparative Example 1. Figure 6 These are microscope images of Example 9. Figure 7 This is a microscope photograph of Example 13.

[0155] [Removal test of barrier membrane]

[0156] A barrier film was formed on a silicon substrate using the film formation methods shown in Examples 1 to 14 and Comparative Example 2. Subsequently, the obtained barrier film was etched twice with Ar ions at 400 W for 10 minutes each time. After each etching process, the contact angle between the substrate surface and water was measured to evaluate the presence or absence of barrier film residue. Regarding the evaluation criteria, a contact angle of 40° or more with water in the first etching process was rated as "A" (Extremely Good); a contact angle of less than 40° in the first etching process but greater than 40° in the second etching process was rated as "B" (Good); and a contact angle of less than 40° in both the first and second etching processes was rated as "C" (Poor). The results are shown in Table 1 below.

[0157] [Table 1]

[0158]

[0159] According to the results in Table 1, it can be seen that the oxidation of Cu wiring can be suppressed when the barrier film containing thin-film titanium oxide is present (Examples 1 to 14) compared to when it is not present (Comparative Examples 1 to 2).

[0160] It was further found that the barrier film containing flake-shaped titanium oxide (Examples 1 to 14) could be easily peeled off by dry etching, just like the titanium oxide film formed by sputtering (Comparative Example 2).

[0161] Explanation of icon numbers

[0162] 1: Wiring board

[0163] 2: Substrate

[0164] 3: Copper wiring

[0165] 4: Barrier membrane

[0166] 5: Insulating film

Claims

1. A wiring substrate, comprising a barrier film directly or indirectly on a substrate having copper wiring, and The barrier film contains sheet-like titanium oxide or sheet-like titanium-metal composite oxide.

2. The wiring substrate according to claim 1, wherein the blocking film is a single-layer film of sheet-like titanium oxide or sheet-like titanium-metal composite oxide.

3. The wiring substrate according to claim 1, wherein the barrier film is a laminated film formed by stacking a single layer of sheet-like titanium oxide or a sheet-like titanium-metal composite oxide.

4. The wiring substrate according to claim 1, wherein the thickness of the barrier film is 1 nm or more and 50 nm or less.

5. The wiring substrate according to claim 1, wherein the barrier film is a laminated film formed by stacking a single layer of sheet-like titanium oxide or a sheet-like titanium-metal composite oxide, and the thickness of the laminated film is more than 2 nm and less than 40 nm.

6. The wiring substrate according to claim 1, wherein the metal in the sheet-like titanium-metal composite oxide is at least one selected from the group consisting of iron, cobalt, nickel and manganese.

7. The wiring substrate according to claim 1, wherein an insulating film is included between the substrate having copper wiring and the barrier film.

8. The wiring substrate according to claim 6, wherein the insulating film is an organic film formed from a curable resin composition.

9. A method for manufacturing a wiring board, comprising manufacturing a wiring board as described in any one of claims 1 to 8, wherein the method for manufacturing the wiring board comprises: The process of directly or indirectly coating a composition for forming a barrier film onto a substrate having copper wiring. The composition for forming the barrier film contains: flake-shaped titanium dioxide or flake-shaped titanium-metal composite oxide, or flake-shaped titanium acid, flake-shaped titanium-metal acid, or salts thereof; and a solvent.

10. A method for manufacturing a wiring board, comprising manufacturing a wiring board as described in any one of claims 1 to 8, wherein the method for manufacturing the wiring board comprises: The process of forming a polymer film directly or indirectly on a substrate having copper wiring, and coating the polymer film with a composition for forming a barrier film; as well as The process of removing the polymer film. The composition for forming the barrier film contains: flake-shaped titanium dioxide or flake-shaped titanium dioxide-metal composite oxide, or flake-shaped titanium acid, flake-shaped titanium-metal acid or salts thereof; and a solvent.

11. A barrier film forming composition for manufacturing a wiring substrate as described in any one of claims 1 to 8, the barrier film forming composition comprising: Flake-shaped titanium dioxide or flake-shaped titanium-metal composite oxides, or flake-shaped titanium acids, flake-shaped titanium-metal acids, or salts thereof; and solvent.

Images