Surface treatment agents, surface treatment methods, and methods for selectively depositing films on substrate surfaces

Abstract

[The technical problem to be solved] The present invention addresses the need to provide a surface treatment agent, a surface treatment method, and a method for selectively forming films on a substrate surface that can suppress hydrophobicity of the insulating region and selectively hydrophobicity of the metal region for a substrate surface comprising adjacent metal and insulating regions. Technical means to solve the problem The solution of the present invention is to use a surface treatment agent for treating the surface of a substrate. The surface is characterized by comprising two or more regions, each region including at least one metal region and at least one insulating region, wherein at least one of the aforementioned metal regions and at least one of the aforementioned insulating regions are adjacent to each other. The surface treatment agent comprises a compound (P) represented by the following general formula (P-1) and an organic solvent (S): HO-P(=O)R1R2‧‧‧(P-1) [In the formula, R1 and R2 are independently bonded to phosphorus atoms and are hydrogen atoms, alkyl, fluorinated alkyl or aromatic hydrocarbon groups that may have substituents. However, R1 and R2 will not be hydrogen atoms at the same time.]

Description

[Technical Field]

[0001] This invention relates to a surface treatment agent, a surface treatment method, and a method for selectively forming films on a substrate surface. [Previous Technology]

[0002] In recent years, the trend towards high integration and miniaturization of semiconductor devices has been increasing. Along with this, the miniaturization of patterned organic films used as masks or patterned inorganic films fabricated through etching processes is progressing. Therefore, there is a growing demand for atomic-level thickness control of organic or inorganic films formed on semiconductor substrates. Atomic layer growth (ALD) is a known method for forming thin films on substrates at the atomic level. Compared to conventional chemical vapor deposition (CVD), ALD is known to offer both high step coverage and film thickness control.

[0003] The ALD (Alternating Layer Deposition) method is a thin film formation technique that alternately supplies two types of gases, which are the main components of the elements constituting the desired film, to a substrate, and repeatedly forms a thin film on the substrate at atomic layer units to achieve the desired film thickness. In the ALD method, the self-limited function of growth is utilized, where, between the supply of raw materials gases, only components of the raw materials gas that form only one or a few atomic layers are adsorbed onto the substrate surface, and excess raw materials gas does not contribute to growth. For example, when forming an Al2O3 film on a substrate, a raw material gas composed of TMA (Trimethyl Aluminum) and an oxidizing gas containing O are used. Furthermore, when forming a nitride film on a substrate, a nitride gas is used instead of an oxidizing gas.

[0004] In recent years, the ALD method has been used to attempt to selectively deposit films on the surface of a substrate (see Patent Document 1 and Non-Patent Document 1). Along with this, there is a search for substrates with a regionally selectively modified surface suitable for use in regionally selective film deposits on substrates obtained by the ALD method. As a method for obtaining a substrate with such a regionally selectively modified surface, a method has been disclosed that, for example, using dodecylphosphonic acid or octadecylphosphonic acid, selectively hydrophobicates a metal substrate or an insulating substrate (see Patent Document 2). However, there is still room for improvement in the selective hydrophobication of the metal substrate for the insulating substrate. [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2003-508897 [Patent Document 2] Japanese Patent Application Publication No. 2021-014631 [Non-Patent Document]

[0006] [Non-Patent Literature 1] J. Phys. Chem. C 2014, 118, 10957-10962 [Summary of the Invention]

[0007] [The problem the invention aims to solve]

[0008] This invention was made in view of the above-mentioned situation, and aims to provide a surface treatment agent, a surface treatment method, and a region-selective film forming method for a substrate surface that can suppress hydrophobicity of the insulating region and more selectively hydrophobize the metal region relative to the substrate surface containing adjacent metal regions and insulating regions. [Means for solving the problem]

[0009] The inventors have discovered that by using a surface treatment agent for treating the surface of a substrate, characterized in that the surface comprises two or more regions, the two or more aforementioned regions comprising at least one metal region and at least one insulating region, and at least one of the aforementioned metal regions and at least one of the aforementioned insulating regions being close to each other, and containing a phosphorus compound (P) and an organic solvent (S) with a specific structure, the above-mentioned problems can be solved, and the present invention is completed.

[0010] The first embodiment of the present invention is a surface treatment agent, which is a surface treatment agent used for treating the surface of a substrate, characterized in that: the surface includes two or more regions, the two or more regions include at least one metal region and at least one insulating region, and at least one of the two or more regions, the metal region and at least one of the insulating regions are close to each other, and contains a compound (P) represented by the following general formula (P-1) and an organic solvent (S), [wherein, R1 and R2 are independently bonded to phosphorus atoms and may have an aromatic hydrocarbon group having hydrogen atoms, alkyl, fluorinated alkyl or substituents, but R1 and R2 are not simultaneously hydrogen atoms].

[0011] The second aspect of the present invention is a surface treatment method for a substrate, characterized in that: the surface comprises two or more regions, the two or more regions comprising at least one metal region and at least one insulating region, and at least one of the metal regions and at least one of the insulating regions being close to each other, comprising exposing the surface to a surface treatment agent of the first aspect, and by reacting the compound (P) with the regions, increasing the contact angle of water in the metal region by at least 10° compared to the contact angle of water in the insulating region close to the metal region.

[0012] The third aspect of the present invention is a method for selectively forming a film on a substrate surface, which includes treating the surface of the substrate using the surface treatment method of the second aspect, and forming a film on the surface of the surface-treated substrate by atomic layer growth, wherein more of the film material is deposited on the insulating region than on the metal region. [Effects of the Invention]

[0013] According to the present invention, a surface treatment agent that can suppress water repellency of the insulating region and more selectively repel water from the metal region relative to the substrate surface containing adjacent metal regions and insulating regions, a surface treatment method using the surface treatment agent, and a region-selective film forming method for the substrate surface using the surface treatment method are provided.

Implementation Method

[0014] <Surface Treatment Agent>

[0015] The surface treatment agent is used to treat the surface of a substrate. The surface of the substrate includes two or more regions. The two or more regions include at least one metal region and at least one insulating region. At least one of the metal regions and at least one of the insulating regions are close to each other. Here, "close" means that the at least one metal region and at least one insulating region share a boundary line and are adjacent, or that they do not share a boundary line and are located in adjacent or separated positions. The surface treatment agent contains a compound (P) represented by the following general formula (P-1) and an organic solvent (S), [wherein, R1 and R2 are independently aromatic hydrocarbon groups bonded to phosphorus atoms and may have hydrogen atoms, alkyl groups, fluorinated alkyl groups or substituents, but R1 and R2 are not both hydrogen atoms]. By using the above-mentioned surface treatment agent, the surface of the substrate is surface-treated, and for the substrate surface containing adjacent metal regions and insulating regions, the hydrophobicity of the insulating regions can be suppressed, and the hydrophobicity of the metal regions can be selectively reduced.

[0016] (Substrate and Substrate Surface) As the object of surface treatment, "substrate" includes, for example, substrates used for the manufacture of semiconductor devices. Examples of such substrates include silicon (Si) substrates, silicon nitride (SiN) substrates, silicon oxide (SiOx) substrates, tungsten (W) substrates, cobalt (Co) substrates, germanium (Ge) substrates, aluminum (Al) substrates, nickel (Ni) substrates, ruthenium (Ru) substrates, copper (Cu) substrates, titanium nitride (TiN) substrates, tantalum nitride (TaN) substrates, and silicon-germanium (SiGe) substrates. The term "substrate surface" includes not only the surface of the substrate itself, but also the surfaces of patterned inorganic layers and unpatterned inorganic layers disposed on the substrate. The surface of a patterned inorganic layer is defined as that which is substantially included in the side or surface of the pattern.

[0017] As a patterned inorganic layer disposed on a substrate, an example is formed by creating an etching mask on the surface of an inorganic layer existing on the substrate using a photoresist method, and then forming a patterned inorganic layer on the surface of the substrate using an atomic layer growth method (ALD). Furthermore, even when a patterned inorganic layer is formed on the surface of the substrate using this ALD method, the surface treatment agent of this embodiment can be used. By using the surface treatment agent of this embodiment as an inorganic layer, selectivity between regions corresponding to metal regions and regions corresponding to insulating regions can be ensured. As an inorganic layer, in addition to the substrate itself, examples include oxide films of the elements constituting the substrate, and films or layers of inorganic materials formed on the surface of the substrate such as silicon nitride (SiN), silicon oxide (SiOx), tungsten (W), cobalt (Co), germanium (Ge), aluminum (Al), nickel (Ni), ruthenium (Ru), copper (Cu), silver (Ag), titanium (Ti), gold (Au), chromium (Cr), molybdenum (Mo), aluminum oxide (Al2O3), titanium oxide (TiO2), zirconium oxide (ZrO2), hafnium oxide (HfO2), tantalum oxide (Ta2O5), titanium nitride (TiN), tantalum nitride (TaN), silicon germanium (SiGe), and silicon oxide (SiO2). While not particularly limited, examples include inorganic films or layers formed during the fabrication of semiconductor devices. Examples of unpatterned inorganic layers disposed on a substrate include films or layers of inorganic materials made of the same material as the patterned inorganic layers disposed on the substrate.

[0018] (Pretreatment of substrate surface) It is preferable to pretreat the substrate surface. The pretreatment agent (hereinafter sometimes referred to as "pretreatment agent") is not particularly limited to any agent that removes the natural oxide film present on the substrate surface and can impart hydroxyl groups to the substrate surface. By pre-applying hydroxyl groups, the water repellency of the substrate surface treated with the surface treatment agent of the present invention is improved. Specifically, examples of pretreatment agents include peroxides such as hydrogen peroxide, perhalogen acids such as periodic acid, oxyacids such as nitric acid or hypochlorous acid, phosphoric acid, citric acid, acetic acid, or hydrofluoric acid (HF). The pretreatment agent can be appropriately selected based on the type of substrate used. For example, in the case of a substrate containing W or Ru, it is preferable to select at least one from the group consisting of hydrogen peroxide and perhalogen acids. Furthermore, when at least one inorganic substance, such as SiO2 or Al2O3, from the group consisting of hydrogen peroxide and perhalogen acids is present on the substrate surface, it is preferable to treat the metal surface without damaging the inorganic substance. On the other hand, when the substrate contains Cu, from the perspective of improving the removal of the natural oxide film and enhancing the hydrophilicity of the substrate surface, it is preferable to use HF aqueous solution, acetic acid, citric acid, phosphoric acid, or nitric acid as a pretreatment agent. One pretreatment agent can be used alone, or two or more can be used.

[0019] (Metallic Region and Insulating Region) The metallic region is composed of a metal or a conductive metal-containing compound. The metallic region can be defined as a conductive region relative to the insulating region described later. Among the aforementioned inorganic materials, copper (Cu), cobalt (Co), aluminum (Al), silver (Ag), nickel (Ni), titanium (Ti), gold (Au), chromium (Cr), molybdenum (Mo), tungsten (W), ruthenium (Ru), titanium nitride (TiN), and tantalum nitride (TaN) are preferred as the metallic or conductive metal-containing compound. The insulating region is composed of one or more insulating compounds selected from the group consisting of oxides, nitrides, carbides, carbonitrides, oxynitrides, oxycarbonitrides, and insulating resins, preferably oxides, nitrides, carbides, carbonitrides, oxynitrides, or oxycarbonitrides. As oxides, preferred materials include aluminum oxide (Al₂O₃), titanium oxide (TiO₂), zirconium oxide (ZrO₂), hafnium oxide (HfO₂), tantalum oxide (Ta₂O₅), silicon oxide (SiO₂(1≦X≦2)), fluorine-containing silicon oxide (SiOF), and carbon-containing silicon oxide (SiOC). As nitrides, preferred materials include silicon nitride (SiN) and boron nitride (BN). As carbides, preferred materials are silicon carbide (SiC). As carbonitrides, preferred materials are silicon carbonitride (SiCN). As oxynitrides, preferred materials are silicon oxynitride (SiON). As oxygen carbonitrides, preferred materials are silicon oxygen carbonitride (SiOCN). As insulating resins, examples include polyimide, polyester, and plastic resins.

[0020] (Patent surface consisting of two regions) As a pattern of a substrate surface consisting of two regions, for example, one of the two regions can be designated as the metal region of the first region, and the region adjacent to it can be designated as the insulating region of the second region. Here, the first region and the second region may be divided into or not divided into a plurality of regions. Examples of the first and second regions include: defining the surface of the substrate itself as the metal region of the first region; defining the layer of insulator formed on the surface of the substrate as the insulating region of the second region; defining the surface of the substrate itself as the insulating region of the first region; defining the layer of metal formed on the surface of the substrate as the metal region of the second region; defining the layer of metal formed on the surface of the substrate as the metal region of the first region; defining the layer of insulator formed on the surface of the substrate as the insulating region of the second region; defining a portion of the surface of the insulating substrate as the metal region of the first region; defining the layer of insulator formed on at least a portion of the surface of the substrate that is not the metal region and / or at least a portion (or the entire surface of the substrate that is not the metal region) as the insulating region of the second region.

[0021] (Patent surface consisting of three or more regions) Examples of a substrate surface consisting of three or more regions include: designating one of the two or more regions as a first region (metal region), designating its adjacent region as a second region (insulator region), and further designating the region adjacent to the second insulator region as a third region (metal region); designating one of the two or more regions as a first region (insulator region), designating its adjacent region as a second region (metal region), and further designating the region adjacent to the second metal region as a third region (insulator region); and designating one of the two or more regions as a first region (metal region), designating its adjacent region as a second region (metal region), and further designating the region adjacent to the second metal region as a third region (insulator region). Here, the first and third regions are made of different materials. Furthermore, the first, second, and third regions may be divided into multiple regions or not. Examples of the first, second, and third regions include: defining the surface of the substrate itself as the first region (metal region), defining the surface of an insulating region adjacent to the substrate and formed on its surface as the second region, and defining the surface of a metal region adjacent to the second region and formed on its surface as the third region; and vice versa. The same approach can be applied even when there are fourth or more regions. While not specifically limited to an upper limit for the number of regions of different materials, it is generally 7 or less, or 6 or less, and typically 5 or less, provided it does not impair the effect of the present invention.

[0022] (Compound (P)) Compound (P) is a hypophosphite derivative. The [HO-P(=O)-] site of Compound (P) is hydrophilic, while the [-R1] and [-R2] sites are hydrophobic. Therefore, in addition to the [HO-P(=O)-] site acting as an adsorption group for the metal region relative to the substrate surface containing adjacent metal and insulating regions, it is presumed that the [-R1] and [-R2] sites act as hydrophobic groups. Therefore, Compound (P) is used as a material (SAM agent) for forming a self-assembled monolayer.

[0023] In the compound (P) represented by formula (P-1), it is preferred that at least one of the alkyl groups of R1 and R2 is a straight-chain or branched alkyl group having 8 or more carbon atoms. Although there is no particular limit to the upper limit of the number of carbon atoms of the alkyl groups of R1 and R2, it is generally possible to be 50 or less or 30 or less.

[0024] Suitable specific examples of alkyl groups for R1 and R2 include, for example, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl, n-eicosyl, n-timoisodecyl and n-timoisodecyl, and alkyl groups that are structurally isomers of such alkyl groups. At least one of the alkyl groups of R1 and R2 is preferably selected from alkyl groups that are structurally isomers of n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl, n-eicosyl, n-timodecyl and n-timodidecyl, and alkyl groups that are structurally isomers of such alkyl groups.

[0025] The compound (P) represented by formula (P-1) is a fluorinated alkyl group of R1 and R2, preferably a straight-chain or branched-chain fluorinated alkyl group with 8 or more carbon atoms.

[0026] As suitable specific examples of fluorinated alkyl groups of R1 and R2, examples of alkyl groups of R1 and R2 exemplified above in which some or all of the hydrogen atoms are replaced by fluorine atoms can be listed.

[0027] The compound (P) represented by formula (P-1) is an aromatic hydrocarbon group with substituents as R1 and R2, such as phenyl, naphthyl, anthracene, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenel, mesitylene, biphenyl, phenanthrene, 2,6-diethylphenyl, 2-methyl-6-ethylphenyl.

[0028] Preferably, one of R1 and R2 is a hydrogen atom, and the other is a straight-chain or branched-chain alkyl group having 8 or more carbon atoms. More preferably, octadecyl, docosyl, or triacontyl is a straight-chain or branched-chain alkyl group having 8 or more carbon atoms.

[0029] Compound (P) may be used alone or in two or more forms.

[0030] From the viewpoint of suppressing hydrophobicity in insulating regions and more selectively hydrophobicating in metal regions, the content of compound (P) is preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.005% by mass or more and 4% by mass or less, even more preferably 0.01% by mass or more and 3% by mass or less, and particularly preferably 0.03% by mass or more and 3% by mass or less, relative to the total mass of the surface treatment agent.

[0031] (Organic Solvent (S)) The organic solvent (S) has the function of enhancing the hydrophobicity of the metal region of the compound (P). Examples of organic solvents (S) include sulphine, sulphine, amides, lactamines, imidazolinones, dialkyl glycol ethers, monoalcohol solvents, (poly)olefin glycol monoalkyl ethers, (poly)olefin glycol monoalkyl ether acetates, other ethers, ketones, other esters, lactones, linear, branched, or cyclic aliphatic hydrocarbons, aromatic hydrocarbons, terpenes, etc.

[0032] As a class of sulfonates, dimethyl sulfonate can be listed as an example.

[0033] As a class of ions, examples include dimethyl ion, diethyl ion, bis(2-hydroxyethyl) ion, and tetramethylene ion.

[0034] Examples of acetamides include N,N-dimethylmethamide, N-methylmethamide, N,N-dimethylacetamide, N-methylacetamide, and N,N-diethylacetamide.

[0035] Examples of lactones include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, and N-hydroxyethyl-2-pyrrolidone.

[0036] Examples of imidazolinones include 1,3-dimethyl-2-imidazolinone, 1,3-diethyl-2-imidazolinone, and 1,3-diisopropyl-2-imidazolinone.

[0037] Examples of dialkyl glycol ethers include dimethyl glycol, dimethyl diethylene glycol, dimethyl triethylene glycol, methyl ethyl diethylene glycol, diethyl glycol, and triethylene glycol butyl methyl ether.

[0038] Examples of monool solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, 3-methyl-3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethyl-1-butanol, sec-heptanol, 3-heptanol, 1-octanol, 2-ethylhexanol, sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, methyl isobutyl methanol (Carbinol), phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, phenylmethyl methanol (Carbinol), diacetone alcohol, and cresol.

[0039] Examples of (poly)olefin glycol monoalkyl ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monoethyl ether.

[0040] As (poly)olefin glycol monoalkyl ether acetates, examples include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate.

[0041] Other ethers include, for example, dimethyl ether, diethyl ether, methyl ethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diisopentyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol monobutyl ether, diethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, and tetrahydrofuran.

[0042] Examples of ketones include methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone, and 2,6-dimethyl-4-heptanone.

[0043] Other esters include, for example, alkyl lactate esters such as methyl lactate and ethyl lactate; ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxypropionate, ethyl hydroxypropionate, methyl 2-hydroxy-3-methylbutyrate, methyl 3-methoxybutylacetate, methyl-3-methoxy-1-butylacetate, methyl-3-methoxybutylpropionate, ethyl acetate. N-propyl acetate, isopropyl acetate, N-butyl acetate, isobutyl acetate, N-pentyl acetate, N-hexyl acetate, N-heptyl acetate, N-octyl acetate, N-pentyl formate, isoamyl acetate, N-butyl propionate, ethyl butyrate, N-propyl butyrate, isopropyl butyrate, butyl butyrate, methyl n-octanoate, methyl decanoate, methyl pyruvate, ethyl pyruvate, N-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl 2-butyrate, dimethyl adipate, propylene glycol diacetate.

[0044] As lactones, examples include propiolactone, γ-butyrolactone, and 6-pentanolactone.

[0045] As straight-chain, branched-chain or cyclic aliphatic hydrocarbons, examples include n-hexane, n-heptane, n-octane, n-nonane, methyloctane, n-decane, n-undecane, n-dodecane, 2,2,4,6,6-pentamethylheptane, 2,2,4,4,6,8,8-heptamethylnonane, cyclohexane, and methylcyclohexane.

[0046] As aromatic hydrocarbons, examples include benzene, toluene, trifluoromethylbenzene, xylene, 1,3,5-trimethylbenzene, naphthalene, and decahydronaphthalene.

[0047] As terpenes, examples include p-menthane, diphenylmenthane, limonene, terpinene, camphene, norbornane, and pinane.

[0048] The relative permittivity of the organic solvent (S) is preferably 35 or less, and more preferably 20 or less, from the viewpoint of more selectively hydrophobic metal regions. Examples of organic solvents (S) with such low relative permittivity include methanol (relative permittivity: 33), diethylene glycol monobutyl ether (BDG) (relative permittivity: 13.70), propylene glycol monomethyl ether (PE) (relative permittivity: 12.71), benzyl alcohol (relative permittivity: 13.70), 2-heptanone (relative permittivity: 11.74), ethylene glycol monobutyl ether acetate (relative permittivity: 8.66), tert-butanol (relative permittivity: 12.5), 1-octanol (relative permittivity: 10.21), isobutanol (relative permittivity: 18.22), trifluoromethylbenzene (relative permittivity: 9.18), decahydronaphthalene (relative permittivity: 2.16), cyclohexane (relative permittivity: 1.99), and decane (relative permittivity: less than 10.5). 1) Ethyl lactate (EL) (relative permittivity: 13.22), diethylene glycol monomethyl ether (relative permittivity: 15.76), 1-nonanol (relative permittivity: 9.13), toluene (relative permittivity: 2.37), propylene glycol monomethyl ether acetate (PM) (relative permittivity: 9.4), methyl isobutyl methanol (Carbinol) (MIBC) (relative permittivity: 10.47), 2,6-dimethyl-4-heptanol (relative permittivity: 2.98), 2-ethyl-1-butanol (relative permittivity: 12.6), 2-butanone oxime (relative permittivity: 2.9), n-dibutyl ether (relative permittivity: 3.33), butyl butyrate (relative permittivity: 4.55), 2,6-dimethyl-4-heptanone (relative permittivity: 9.82), etc.

[0049] The organic solvent (S) may be used alone or in more than two types.

[0050] (Other components) Other components that can be incorporated into the surface treatment agent can suppress the hydrophobicity of the insulating region relative to the substrate surface containing adjacent metal regions and insulating regions, and can enhance the effect of more selectively hydrophobicating the metal region, or can be used in a range that does not impede, such as acidic or alkaline nitrogen-containing compounds other than compound (P), pH adjusters, antioxidants, ultraviolet absorbers, viscosity adjusters, defoamers, etc.

[0051] (Acid other than compound (P)) As an acid, if it is other than the above-mentioned compound (P), it can be any of organic acid and inorganic acid.

[0052] As organic acids, examples include carboxylic acids such as formic acid, acetic acid, citric acid, oxalic acid, 2-nitrophenylacetic acid, 2-ethylhexane acid, dodecanoic acid, and 2-hydroxy-1,2,3-propanetricarboxylic acid; glycolic acids such as ascorbic acid, tartaric acid, and glucuronic acid; and sulfonic acids such as benzenesulfonic acid and p-toluenesulfonic acid. As inorganic acids, examples include hydrofluoric acid (HF), phosphonic acid (HP(=O)(OH)2), phosphoric acid (H3PO4), hydrochloric acid, nitric acid, and boric acid. Among these, as acids, carboxylic acids or inorganic acids are preferred, more preferably acetic acid, 2-hydroxy-1,2,3-propanetricarboxylic acid, phosphonic acid (HP(=O)(OH)2), or hydrofluoric acid (HF), even more preferably phosphonic acid (HP(=O)(OH)2) or hydrofluoric acid (HF), and especially preferably hydrofluoric acid.

[0053] (Basic Nitrogen Compounds) The term "basic nitrogen compound" refers to a compound that inhibits hydrophobicity in the insulating region of compound (P). While the exact nature of this property is uncertain, it is presumed to be due to the adsorption of the cations of the basic nitrogen compound in the insulating region, thus hindering the adsorption of compound (P) into the insulating region. While not particularly limited, basic nitrogen compounds possessing this property can include, for example, quaternary ammonium compounds, pyridonium halides, pyrrolidineonium halides, bipyridonium halides, or amines or their salts with a pKb of 2.5 or less (hereinafter also referred to as "low pKb amines").

[0054] As a fourth-order ammonium compound, for example, a fourth-order ammonium salt represented by the following formula (b1) can be listed.

[0055] In formula (b1), Ra1 to Ra4 independently represent an alkyl group having 1 to 16 carbon atoms, an aryl group having 6 to 16 carbon atoms, an aralkyl group having 7 to 16 carbon atoms, or a hydroxyalkyl group having 1 to 16 carbon atoms. At least two of Ra1 to Ra4 can be bonded to each other to form a cyclic structure, especially at least one of the combinations of Ra1 and Ra2 and Ra3 and Ra4 can be bonded to each other to form a cyclic structure. In formula (b1), X- represents a hydroxide ion, a chloride ion, a fluoride ion, or an organic carboxylic acid ion that may contain fluorine. Examples of organic carboxylic acid ions that may contain fluorine include acetate ions and trifluoroacetic acid ions.

[0056] Among the compounds represented by formula (b1), tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, methyltripropylammonium, methyltributylammonium, ethyltrimethylammonium, dimethyldiethylammonium salt, benzyltrimethylammonium, hexadecyltrimethylammonium, (2-hydroxyethyl)trimethylammonium, and hydroxides, chlorides, or fluorides of spirocyclic-(1,1')-bipyrrolidineonium are preferred from the point of ease of acquisition, and more preferably hydroxides or fluorides for the effect of the present invention, and even more preferably hydroxides or fluorides of tetramethylammonium and benzyltrimethylammonium. As pyridinium halides, chlorides or fluorides of pyridinium can be listed, with fluorides being preferred. As pyrrolidineonium halides, chlorides or fluorides of pyrrolidineonium can be listed, with fluorides being preferred. Examples of bipyridinium halides include chlorides or fluorides of bipyridinium, with fluorides being preferred.

[0057] The pKb of a low pKb amine is preferably 2.0 or less, and more preferably 1.5 or less. Examples of low pKb amines include guanidine derivatives. Furthermore, the pKb value is measured at 25°C.

[0058] Examples of guanidine derivatives include methylguanidine, dimethylguanidine, trimethylguanidine, tetramethylguanidine, or their chloride or fluoride salts. Among these, tetramethylguanidine or its fluoride salt is preferred.

[0059] The surface treatment agent is obtained by mixing the aforementioned compound (P), organic solvent (S), and other components, if necessary, using a known method.

[0060] <Surface Treatment Method> Next, a surface treatment method using the aforementioned surface treatment agent will be described. The surface treatment method is a surface treatment method for the surface of a substrate. The surface of the substrate includes two or more regions. The two or more regions include at least one metal region and at least one insulating region. At least one of the metal regions and at least one of the insulating regions are close to each other. Here, "close" means that at least one of the metal regions and at least one of the insulating regions share a boundary line and are adjacent, or that they do not share a boundary line and are located in adjacent or separated positions. The surface treatment method includes exposing the surface to the aforementioned surface treatment agent. In the surface treatment method, by reacting the aforementioned compound (P) with the aforementioned regions, the contact angle of water in the metal region is increased by at least 10° compared to the contact angle of water in the insulating region adjacent to the metal region.

[0061] The substrate and substrate surface, metal region and insulating region that are the objects of the surface treatment method, and the surface treatment agent used in the surface treatment method are the same as the substrate and substrate surface, metal region and insulating region and surface treatment agent mentioned above.

[0062] In the surface treatment method, the contact angle of water in the metal region is increased by more than 10° compared to the contact angle of water in the insulating region adjacent to the metal region. This demonstrates water-repellent properties in the metal region and suppresses water-repellent properties in the insulating region.

[0063] (Exposure) As a method of exposing the surface of a substrate to a surface treatment agent, a method can be listed that applies the surface treatment agent to (e.g., coats) the surface of the substrate and exposes it by means of coating methods such as immersion coating, spin coating, roller coating and blade coating.

[0064] The exposure temperature is, for example, 10°C to 90°C, preferably 20°C to 80°C, more preferably 20°C to 70°C, and even more preferably 20°C to 30°C. The exposure time, from the viewpoint of repelling the water in the metal region and suppressing the water repellency in the insulating region, is preferably 20 seconds or more, more preferably 30 seconds or more, and even more preferably 45 seconds or more. While there is no particular limitation on the upper limit of the exposure time, it is generally less than 2 hours, typically less than 1 hour, preferably less than 15 minutes, even more preferably less than 5 minutes, and particularly preferably less than 2 minutes. After the above exposure, washing and / or drying may be performed if necessary. Washing may be performed, for example, by water rinsing or surfactant cleaning. Drying may be performed by nitrogen blowing.

[0065] Through the above-described exposure, the compound (P) can be selectively adsorbed relative to the metal region in the adjacent metal region and insulating region. As a result, the contact angle of water relative to the metal region can be increased by 10° or more, more preferably by 15° or more, more preferably by 20° or more, and even more preferably by 25° or more compared to the contact angle of water relative to the insulating region adjacent to the metal region. The contact angle of water relative to the substrate surface exposed to the surface treatment agent can be set to, for example, 50° or more and 140° or less. By controlling the material of the substrate surface, the type and amount of surface treatment agent used, and the exposure conditions, the contact angle of water can be set to 50° or more, more preferably 60° or more, more preferably 70° or more, and even more preferably 90° or more. Although there is no particular limitation on the upper limit of the above-described contact angle, it is, for example, 140° or less, and generally 130° or less. More specifically, the water contact angle of the metallic region is preferably 70° or higher, more preferably 80° or higher, more preferably 90° or higher, and even more preferably 100° or higher. While not specifically limited to the upper limit of the aforementioned contact angle, it is, for example, 140° or lower. The water contact angle of the insulating region is preferably 70° or lower, more preferably 65° or lower, and even more preferably 60° or lower. While not specifically limited to the lower limit of the aforementioned contact angle, it is, for example, 50° or higher.

[0066] <Region-Selective Film Forming Method for Substrate Surface> Next, a region-selective film forming method for a substrate surface using the above-described surface treatment method will be described. The region-selective film forming method for a substrate surface includes treating the surface of the substrate using the above-described surface treatment method, and forming a film on the surface of the surface-treated substrate using atomic layer growth (ALD) to deposit more of the film material on the insulating region than on the metal region.

[0067] As a result of the above surface treatment, the contact angle of water in the metal region can be increased by more than 10° compared to the contact angle of water in the insulating region that is close to the metal region. In the metal region, where the water contact angle is larger than the insulating region, it becomes difficult for the film-forming material formed by the ALD method to adhere to the substrate surface. As a result, by repeating the ALD cycle, a thick film can be selectively formed on the insulating region.

[0068] (Film Formation by ALD Method) While not particularly limited, the film formation method by ALD method is preferably a film formation method using the adsorption of at least two gas-phase reactants (hereinafter also referred to as "precursor gases"). The adsorption of precursor gases is preferably chemical adsorption. Specifically, a method including the following steps (a) and (b), repeating the following steps (a) and (b) at least once (1 cycle) until the desired film thickness is obtained, etc. (a) is a step of exposing the substrate surface-treated by the method of the second state above to a pulse of the first precursor gas and (b) following the above step (a), exposing the substrate to a pulse of the second precursor gas.

[0069] The process after step (a) and before step (b) may or may not include a plasma treatment step, or a step of removing or venting (purifying) the first precursor gas and its reactants using a carrier gas, a second precursor gas, etc. After step (b), the process may or may not include a plasma treatment step, or a step of removing or purging the second precursor gas and its reactants using a carrier gas, etc. Examples of carrier gases include inert gases such as nitrogen, argon, and helium.

[0070] Each pulse in each cycle and each layer formed is preferably self-controlled, more preferably each layer formed is a single-atom layer. The film thickness of the aforementioned single-atom layer can be, for example, 5 nm or less, preferably 3 nm or less, more preferably 1 nm or less, and even more preferably 0.5 nm or less.

[0071] As the first precursor gas, organometallic compounds, metal halides, and metal oxide halides can be listed, specifically, tantalum pentaethoxy, titanium tetra(dimethylamino), tantalum tetra(dimethylamino), zirconium tetra(dimethylamino), hafnium tetra(dimethylamino), silane tetra(dimethylamino), copper hexafluoroacetate vinyltrimethylsilane, Zn(C2H5)2, Zn(CH3)2, TMA (trimethylaluminum), TaCl5, WF6, WOCl4, CuCl, ZrCl4, AlCl3, TiCl4, SiCl4, HfCl4, etc.

[0072] As the second precursor gas, examples include precursor gases that can decompose the first precursor or precursor gases that can remove the ligands of the first precursor. Specifically, examples include H2O, H2O2, O2, O3, NH3, H2S, H2Se, PH3, AsH3, C2H4 or Si2H6, etc.

[0073] The exposure temperature in step (a) is not particularly limited, but for example, it is 25°C or higher and 800°C or lower, preferably 50°C or higher and 650°C or lower, more preferably 100°C or higher and 500°C or lower, and even more preferably 150°C or higher and 375°C or lower.

[0074] The exposure temperature in step (b) is not particularly limited, but can be listed as a temperature that is substantially equal to or higher than the exposure temperature in step (a). While not particularly limited, films formed by the ALD method can include those containing pure elements (e.g., Si, Cu, Ta, W), oxides (e.g., SiO2, GeO2, HfO2, ZrO2, Ta2O5, TiO2, Al2O3, ZnO, SnO2, Sb2O5, B2O3, In2O3, WO3), nitrides (e.g., Si3N4, TiN, AlN, BN, GaN, NbN), carbides (e.g., SiC), sulfides (e.g., CdS, ZnS, MnS, WS2, PbS), selenides (e.g., CdSe, ZnSe), phosphides (GaP, InP), arsenides (e.g., GaAs, InAs), or mixtures thereof. [Example]

[0075] Hereinafter, although the present invention will be described in more detail with reference to embodiments and comparative examples, the present invention is not limited to the following embodiments.

[0076] [Example 1 and Comparative Example 1] (Preparation of Surface Treatment Agent) The following compound (P) was uniformly mixed in the following organic solvent (S) at the amounts listed in Table 1 below to prepare the surface treatment agent for Example 1 and Comparative Example 1. As compound (P), P1 to P2 were used. P1: Octadecyl hypophosphite P2: Octadecylphosphonic acid As organic solvent (S), S1 was used. S1: Isobutanol

[0077] (Pretreatment, Surface Treatment) Using the surface treatment agents obtained in Example 1 and Comparative Example 1, surface treatment of Cu substrates, W substrates, TaN substrates, and SiO2 substrates was performed according to the following method. Specifically, each substrate was immersed in an HF aqueous solution with a concentration of 25 ppm at 25°C for 1 minute for pretreatment. After the above pretreatment, each substrate was washed with deionized water for 1 minute. Each substrate after washing was dried by a nitrogen stream. Each dried substrate was immersed in the above surface treatment agents at 25°C for 1 minute for surface treatment. Each surface-treated substrate was washed with isopropanol for 1 minute, and then washed with deionized water for 1 minute. Each washed substrate was dried by a nitrogen stream to obtain each surface-treated substrate.

[0078] (Determination of water contact angle) The water contact angle was measured for each substrate after only the above surface treatment and for each substrate after the above pretreatment. The water contact angle was measured using a Dropmaster 700 (manufactured by Kyowa Interface Science Co., Ltd.). A drop of pure water (2.0 μL) was dropped onto the surface of each substrate, and the contact angle was measured 2 seconds after the drop. The results are shown in Table 1.

[0079]

[0080] Table 1, "Reference Comparative Example 1," indicates test cases where only the pretreatment was performed, in addition to the pretreatment and surface treatment described above. From Table 1, when surface-treated with the surface treatment agent of Example 1, compared to surface-treated with the surface treatment agent of Comparative Example 1, the water contact angle on the Cu substrate, W substrate, and TaN substrate of the metal substrate increased. From these experimental results, it is understood that the octadecyl phosphoric acid used in Example 1 can more effectively repel water from these metal substrates compared to the octadecylphosphonic acid used in Comparative Example 1. On the other hand, the water contact angle on the SiO2 substrate of the insulating substrate is the same between Example 1 and Comparative Example 1. Furthermore, the water contact angle on the SiO2 substrate is the same between surface-treated with the surface treatment agent of Example 1 and Reference Comparative Example 1. From these experimental results, it is understood that the octadecyl phosphoric acid used in Example 1 did not repel water from the aforementioned insulating substrate. Combining the above experimental results, it can be said that octadecyl phosphoric acid can more selectively repel water from metal substrates than octadecylphosphonic acid.

[0081] (ALD film formation test of Al2O3 on Cu substrate) Using the surface treatment agents of Example 1 and Comparative Example 1, surface treatment and ALD film formation tests of Al2O3 on Cu substrates were performed in the following order: (Sequence) 1. The Cu substrate was pretreated by immersing it in an HF aqueous solution with a concentration of 25 ppm at 25°C for 1 minute. 2. The pretreated Cu substrate was washed with deionized water for 1 minute. The washed Cu substrate was dried by a nitrogen stream. 3. The dried Cu substrate was immersed in the surface treatment agent for 1 minute, then washed with isopropanol with stirring for 1 minute, and then washed with deionized water and bleed with nitrogen. 4. 91 ALD cycles were performed under the following conditions: ･ Atomic layer deposition (ALD) apparatus: AT-410 (manufactured by Anric Technologies) ･ Chamber temperature: 150°C ･ Precursors: trimethylaluminum and H2O

[0082] The film thickness of Al2O3 was measured by fluorescence X-ray analysis for Cu substrates after 0, 45, 91 and ALD cycles.

[0083] Of the above sequences 1 to 4, the test example in which only the ALD film was formed by the surface treatment agents of sequences 1 to 3 was not performed, and was referred to as "Reference Comparative Example 2". The film thickness of Al2O3 was measured using the same method as described above. Furthermore, the ALD blocking rate was calculated from the film thickness of Al2O3 obtained by surface treatment with the surface treatment agents of Example 1 and Comparative Example 1, and the film thickness of Al2O3 obtained in Reference Comparative Example 2, according to the following formula. The results are shown in Table 2.

[0084] ALD blocking rate (%) = [1 - (Al2O3 film thickness during surface treatment with surface treatment agent) / (Al2O3 film thickness in Comparative Example 2)] × 100

[0085]

[0086] Based on the results of Comparative Example 2, when the Cu substrate was not surface-treated with a surface treatment agent but ALD film was formed, the Al2O3 film thickness was approximately 10 nm after 91 cycles. When the Cu substrate was surface-treated with the surface treatment agent of Comparative Example 1, the Al2O3 film thickness decreased to 2.6 nm after 91 cycles, and the ALD blocking rate also remained at 74.0%. On the other hand, when the surface treatment agent of Example 1 was used, the Al2O3 film thickness decreased significantly to 0.7 nm after 91 cycles, and the ALD blocking rate increased significantly to 92.7%.

[0087] (ALD film formation test of Al2O3 on SiO2 substrate) The above-mentioned ALD film formation test of Al2O3 on Cu substrate was conducted using a SiO2 substrate instead of a Cu substrate, and the ALD film formation test was performed in the same order as above, with 45 ALD cycles. The results are shown in Table 3.

[0088]

[0089] From the results of Comparative Example 2, when the SiO2 substrate was not surface-treated with a surface treatment agent, but ALD film formation was performed, the Al2O3 film thickness was approximately 5.0 nm after 45 cycles. When the SiO2 substrate was surface-treated with the surface treatment agents of Example 1 and Comparative Example 1, the Al2O3 film thickness was almost the same as that of the Comparative Example after 45 cycles. From these experimental results, it is understood that octadecyl hypophosphite and octadecylphosphonic acid are the same and do not hinder ALD film formation on the SiO2 substrate.

[0090] [Examples 1-10 and Comparative Example 2] (Preparation of Surface Treatment Agent) Surface treatment agents of Examples 1-10 and Comparative Example 2 were prepared as saturated solutions of the following compound (P) and the following solvent at room temperature. As compound (P), P1 was used. P1: Octadecyl hypophosphoric acid. As solvent, S1-S10 and S11, which are equivalent to organic solvents (S), were used. S1: Isobutanol (relative permittivity: 18.22) S2: Toluene (relative permittivity: 2.37) S3: Butyl butyrate (relative permittivity: 4.55) S4: Trifluoromethylbenzene (relative permittivity: 9.18) S5: Propylene glycol monomethyl ether acetate (relative permittivity: 9.40) S6: 1-Octanol (relative permittivity: 10.21) S7: Methyl isobutyl methanol (Carbinol) (relative permittivity: 10.47) S8: Propylene glycol monomethyl ether (relative permittivity: 12.71) S9: Benzyl alcohol (relative permittivity: 13.70) S10: γ-Butyrolactone (relative permittivity: 42.10) S11: Water (relative permittivity: 78.36)

[0091] (ALD film formation test of Al2O3 on Cu substrate) Using the surface treatment agents of Examples 1-10 and Comparative Example 2, surface treatment of Cu substrate and ALD film formation test of Al2O3 were performed in the following order: (Sequence) 1. The Cu substrate was pretreated by immersing it in an HF aqueous solution with a concentration of 25 ppm at 25°C for 1 minute. 2. The pretreated Cu substrate was washed with deionized water for 1 minute. The washed Cu substrate was dried by a nitrogen stream. 3. The dried Cu substrate was immersed in the surface treatment agent for 1 minute, then washed with isopropanol with stirring for 1 minute, and then washed with deionized water and bleed with nitrogen. 4. 45 ALD cycles were performed under the following conditions: ･ Atomic layer deposition (ALD) device: AT-410 (manufactured by Anric Technologies) ･ Chamber temperature: 150°C ･ Precursors: trimethylaluminum and H2O

[0092] The thickness of the Al2O3 film was measured by fluorescence X-ray analysis on the Cu substrate after 45 ALD cycles. The results are shown in Table 4.

[0093] (Determination of Water Contact Angle) In the above ALD film formation test, the water contact angle was measured for the Cu substrate after nitrogen blowing in sequence 3 and the Cu substrate after ALD cycle treatment in sequence 4. The water contact angle was measured using a Dropmaster 700 (manufactured by Kyowa Interface Science Co., Ltd.). A drop of pure water (2.0 μL) was dropped onto the surface of each substrate, and the contact angle was measured 2 seconds after the drop. The results are shown in Table 4.

[0094]

[0095] Table 4, "Reference Comparative Example 3," represents the test example in which the surface treatment in sequence 3 was not performed among the ALD film formation tests in sequences 1 to 4 above. From the results of Reference Comparative Example 3, when the Cu substrate was not surface-treated with a surface treatment agent but ALD film formation was performed, the Al2O3 film thickness became approximately 5.0 nm after 45 cycles. When the Cu substrate was surface-treated with the surface treatment agent of Comparative Example 2, the Al2O3 film thickness became approximately 4.7 nm, and the Al2O3 film thickness was hardly reduced. On the other hand, when surface-treated with the surface treatment agents of Examples 1 to 10, it was found that the Al2O3 film thickness was reduced in all cases. In Examples 1 to 10, when surface-treated with a surface treatment agent incorporating an organic solvent with a low relative permittivity, the reduction effect on the Al2O3 film thickness was increased.

Claims

1. A surface treatment agent for treating the surface of a substrate, characterized in that: the surface comprises two or more regions, the two or more aforementioned regions comprising at least one metal region and at least one insulating region, and at least one of the aforementioned metal regions and at least one of the aforementioned insulating regions being close to each other, comprising a compound (P) represented by the following general formula (P-1) and an organic solvent (S), [wherein, R1 and R2 are independently bonded to phosphorus atoms and are hydrogen atoms, alkyl groups, fluorinated alkyl groups or aromatic hydrocarbon groups that may have substituents, but R1 and R2 are not simultaneously hydrogen atoms].

2. The surface treatment agent as described in claim 1, wherein, The relative permittivity of the aforementioned organic solvent (S) is 35 or less.

3. The surface treatment agent as described in claim 2, wherein, The relative permittivity of the aforementioned organic solvent (S) is 20 or less.

4. The surface treatment agent as described in any of claims 1 to 3, wherein, The aforementioned metal is selected from one or more of the group consisting of copper, cobalt, aluminum, silver, nickel, titanium, gold, chromium, molybdenum, tungsten, ruthenium, titanium nitride, and tantalum nitride, and the aforementioned insulator is selected from one or more of the group consisting of alumina, titanium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silicon oxide, fluorine-containing silicon oxide, carbon-containing silicon oxide, silicon nitride, boron nitride, silicon carbide, silicon carbonitride, silicon oxynitride, and silicon oxycarbonitride.

5. A surface treatment method for a substrate surface, characterized in that: the surface comprises two or more regions, the two or more aforementioned regions comprising at least one metal region and at least one insulating region, and at least one of the aforementioned metal regions and at least one of the aforementioned insulating regions being close to each other, comprising exposing the aforementioned surface to a surface treatment agent as claimed in any one of claims 1 to 4, wherein the contact angle of water in the aforementioned metal region is increased by more than 10° compared with the contact angle of water in the aforementioned insulating region that is close to the aforementioned metal region by the reaction of the aforementioned compound (P) with the aforementioned region.

6. A method for selectively forming a film on a substrate surface, comprising treating the aforementioned surface of the substrate by the surface treatment method of claim 5, and forming a film on the surface of the surface-treated substrate by atomic layer growth, wherein more of the aforementioned film material is deposited on the aforementioned insulating region than on the aforementioned metal region.