Surface treatment agents, surface treatment methods, and field-selective film formation methods for substrate surfaces

Abstract

A surface treatment agent for treating a substrate that has undergone a pretreatment with an oxidant, the substrate having a surface comprising two or more regions of different materials, and at least one of the two or more regions containing a metal surface, characterized in that the surface treatment agent contains a compound (P) represented by the following general formula (P-1) and an organic solvent (S) with a specific dielectric constant of 35 or less (where R1 is an alkyl group, R2 and R3 are hydrogen atoms or alkyl groups, etc.).

Description

Technical Field

[0001] This invention relates to a surface treatment agent, a surface treatment method, and a field-selective film formation method for a substrate surface. This case asserts priority based on Japanese Patent Application No. 2020-214226 filed in Japan on December 23, 2020, and its contents are incorporated herein by reference. Prior Technology

[0002] In recent years, the trend of increasing integration and miniaturization of semiconductor devices has led to the miniaturization of organic patterns for masking or inorganic patterns made by etching processes, which in turn requires atomic-level film thickness control. Atomic layer deposition (ALD) is a known method for forming thin films on a substrate at the atomic level. Compared with conventional chemical vapor deposition (CVD), ALD is known to have both higher step coverage and film thickness control.

[0003] ALD (Alternating Layer Deposition) is a thin film formation technique that involves alternating supply of two gases, with the elements constituting the desired film as the main components, to a substrate, forming a thin film on the substrate in atomic layer units, and repeating this process multiple times to form a film of the desired thickness. In the ALD method, the growth self-control function (self-limitation function) is utilized, which means that during the supply of raw material gas, only one or several layers of raw material gas components are adsorbed on the substrate surface, and excess raw material gas is not beneficial to growth. For example, when forming an Al₂O₃ film on a substrate, a material composed of TMA (…) is used. The raw material gas is composed of TriMethyl Aluminum and an oxygen-containing oxidizing gas. Furthermore, when forming a nitride film on the substrate, a nitride gas is used instead of an oxidizing gas.

[0004] In recent years, some researchers have attempted to use the ALD method to selectively deposit films on the surface of a substrate (see Non-Patent Literature 1 and 2). Consequently, in order to be suitable for field-selective film formation methods on substrates produced by the ALD method, a substrate with a field-selective surface modification is required. In the film fabrication method, by using the ALD method, it is expected that the thickness control of the patterned atomic layer will achieve step coverage and miniaturization. [Previous Technical Documents] [Non-patent literature]

[0005] [Non-patent literature 1] J. Phys. Chem. C 2014, 118, 10957-10962 [Non-Patent Literature 2] ACS NANO Vol.9, No.9, 8710-8717 (2015) Summary of the Invention

[0006] [The problem that the invention aims to solve]

[0007] However, the methods described in Non-Patent Documents 1 and 2 have the problem that the surface modification of the substrate requires a long time depending on the type of substrate, in order to selectively modify the surface.

[0008] The present invention was made in view of the above-mentioned facts, and aims to provide a surface treatment agent that can shorten the processing time in a method for processing a substrate having a surface having two or more areas with different materials, a surface treatment method using the surface treatment agent, and a method for selectively forming films on the surface of a substrate to which the surface treatment method is applied. [Methods for solving problems]

[0009] To address the aforementioned issues, the present invention employs the following configuration.

[0010] The first embodiment of the present invention is a surface treatment agent for treating a substrate that has undergone a pretreatment with an oxidant. The substrate has a surface comprising two or more regions of different materials, and at least one of the two or more regions contains a metal surface. The surface treatment agent is characterized in that it contains a compound (P) represented by the following general formula (P-1) and an organic solvent (S) with a specific dielectric constant of 35 or less. [In the formula, R1 is a straight-chain or branched alkyl group, a straight-chain or branched fluoroalkyl group, or an aromatic hydrocarbon group that may have substituents, and R2 and R3 are, respectively, a hydrogen atom, a straight-chain or branched alkyl group, a straight-chain or branched fluoroalkyl group, or an aromatic hydrocarbon group that may have substituents].

[0011] The second aspect of the present invention is a surface treatment method for a substrate having a surface comprising two or more regions of different materials, and at least one of the two or more aforementioned regions containing a metal surface. The method is characterized by pretreating the aforementioned surface with an oxidizing agent and exposing it to a surface treatment agent as described in the first aspect.

[0012] The third aspect of the present invention is a method for selectively depositing a film on a substrate surface, which includes treating the surface of the substrate by the surface treatment method of the second aspect described above, and forming a film on the surface of the substrate before surface treatment by atomic layer deposition, wherein the deposition amount of the film material is selectively different in different areas. [Effects of the Invention]

[0013] According to the present invention, a surface treatment agent that can shorten the processing time in a method for processing a substrate having a surface comprising two or more regions of different materials, a surface treatment method using the surface treatment agent, and a region-selective film forming method for the substrate surface to which the surface treatment method is applied can be provided. Simple Explanation of the Diagram

[0014] [Figure 1] shows the XPS analysis results of the surface-treated substrate in the experimental example. Implementation

[0015] [Forms of Invention Implementation] <First type: Surface treatment agent>

[0016] The surface treatment agent of the first embodiment of the present invention is a surface treatment agent used to treat a substrate that has been pretreated with an oxidant. The aforementioned substrate is a surface that includes at least one region containing two or more regions containing a metal surface, and the regions adjacent to each other among the two or more aforementioned regions are surfaces with different materials (hereinafter referred to as "the surface to be treated").

[0017] The surface to be treated by the surface treatment agent applicable to this embodiment includes at least one region comprising two or more regions containing a metal surface, and the materials of adjacent regions among the two or more aforementioned regions are different from each other.

[0018] In this embodiment, when the surface to be processed comprises two regions, the surface to be processed includes a first region containing a metallic surface and a second region with a different material from the first region and adjacent to the first region. In this case, the "adjacent regions" are the first region and the second region. Here, the first region and the second region may be divided into multiple regions or may not be divided into multiple regions.

[0019] In this embodiment, when the surface to be processed comprises three or more regions, the surface to be processed includes a first region containing a metallic surface, a second region with a different material from the first region and adjacent to the first region, and a third region with a different material from the second region and adjacent to the second region. In this case, "adjacent regions" can refer to the first region and the second region (i.e., adjacent regions) or the first region and the third region (i.e., regions separated by a middle). Furthermore, when the first region and the third region have different materials (i.e., both the first region and the third region contain metallic surfaces), "adjacent regions" refers to the first region and the second region or the second region and the third region (i.e., adjacent regions). Therefore, the first, second, and third domains may be divided into multiple domains or not divided into multiple domains. In this embodiment, the same approach can also be applied when the surface being processed includes a fourth or more domains. The upper limit of the number of areas with different materials is not particularly limited as long as it does not impair the effect of the present invention. For example, it can be 7 or less or 6 or less, typically 5 or less.

[0020] In this embodiment, the metal surface contained in the surface being treated is not particularly limited, and examples include metal surfaces containing at least one of the group consisting of tungsten, ruthenium, copper and cobalt; and metal surfaces containing at least one of the group consisting of tungsten and ruthenium.

[0021] In this embodiment, the surface to be treated is pretreated with an oxidant. The oxidizing agent used for pretreatment of the surface to be treated (hereinafter referred to as "oxidizing agent for pretreatment") is not particularly limited if it can remove the natural oxide film present on the surface to be treated and impart hydroxyl groups to the surface to be treated. Specifically, examples of oxidizing agents for pretreatment include peroxides such as hydrogen peroxide, perhalic acids such as periodic acid, and oxyacids such as nitric acid or hypochlorous acid. From the viewpoint of improving the water repellency of the surface to be treated, the oxidizing agent for pretreatment is preferably selected from at least one of the groups consisting of hydrogen peroxide and perhalic acids. Furthermore, selecting at least one of the groups consisting of hydrogen peroxide and perhalic acids is also preferable from the viewpoint of treating the metal surface without damaging inorganic substances such as SiO2 and Al2O3 when they coexist on the surface to be treated.

[0022] In this embodiment, the oxidant used for pretreatment can be a single type or two or more types.

[0023] The surface treatment agent of this embodiment contains a compound (P) represented by the following general formula (P-1) and an organic solvent (S) with a specific dielectric constant of 35 or less.

[0024] [In the formula, R1 is a straight-chain or branched alkyl group, a straight-chain or branched fluoroalkyl group, or an aromatic hydrocarbon group that may have substituents; R2 and R3 are each independently a hydrogen atom, a straight-chain or branched alkyl group, a straight-chain or branched fluoroalkyl group, or an aromatic hydrocarbon group that may have substituents].

[0025] Compound (P) Compound (P) is a phosphonic acid or a derivative thereof represented by the aforementioned general formula (P-1). In the aforementioned general formula (P-1), R1 is a straight-chain or branched alkyl group, a straight-chain or branched fluoroalkyl group, or an aromatic hydrocarbon group that may have substituents.

[0026] In the aforementioned general formula (P-1), the straight-chain or branched alkyl group of R1 preferably has 1 to 45 carbons, more preferably 5 to 40 carbons, and even more preferably 8 to 35 carbons. R1 can be a straight-chain or branched alkyl group, specifically including methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, isotriadecyl, tetradecyl, pentadecyl, hexadecyl, isochoryl, heptadecanyl, octadecyl, nonadecanyl, eicosyl, dodecyl, dodecyl, and various isomers of the above alkyl groups.

[0027] In the aforementioned general formula (P-1), the straight-chain or branched fluoroalkyl group of R1 can be a group in which some or all of the hydrogen atoms of the aforementioned straight-chain or branched alkyl group are substituted with fluorine atoms.

[0028] In the aforementioned general formula (P-1), the aromatic hydrocarbon group that may have substituents in R1 can be phenyl, naphthyl, anthracene, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumene, mesitylene, biphenyl, phenanthrene, 2,6-diethylphenyl, 2-methyl-6-ethylphenyl, etc.

[0029] R1 is preferably a straight-chain or branched alkyl group having 8 or more carbon atoms, and more preferably a dodecyl or octadecyl group.

[0030] Examples of straight-chain or branched alkyl groups, straight-chain or branched fluoroalkyl groups, or aromatic hydrocarbon groups that may have substituents in R2 and R3 are the same as those of straight-chain or branched alkyl groups, straight-chain or branched fluoroalkyl groups, or aromatic hydrocarbon groups that may have substituents in R1. Among them, R2 and R3 are preferably hydrogen atoms.

[0031] In this embodiment, compound (P) may be used alone or in two or more forms. In the surface treatment agent of this embodiment, the content of compound (P) relative to the total mass of the surface treatment agent is preferably 0.0001 to 5% by mass, more preferably 0.001 to 4% by mass, even more preferably 0.005 to 3% by mass, and even more preferably 0.008 to 3% by mass. When the content of compound (P) is within the above-mentioned suitable range, compound (P) is more easily adsorbed onto areas containing metal surfaces, thereby easily improving the selectivity of the surface treatment agent for areas containing metal surfaces.

[0032] Organic solvents (S) As an organic solvent (S), there are no particular limitations if the specific dielectric constant is below 35. Examples include methanol (specific dielectric constant: 33), diethylene glycol monobutyl ether (BDG) (specific dielectric constant: 13.70), propylene glycol monomethyl ether (PE) (specific dielectric constant: 12.71), benzyl alcohol (specific dielectric constant: 12.70), 2-heptanone (specific dielectric constant: 11.74), butylene acetate (specific dielectric constant: 8.66), tributanol (specific dielectric constant: 12.5), 1-octanol (specific dielectric constant: 10.21), isobutanol (specific dielectric constant: 18.22), benzene trifluoride (specific dielectric constant: 9.18), decahydronaphthalene (specific dielectric constant: 2.16), cyclohexane (specific dielectric constant: 1.99), decane (specific dielectric constant: less than 1), isobutylene... Alcohol (specific dielectric constant: 18.22), ethyl lactate (EL) (specific dielectric constant: 13.22), diethylene glycol monomethyl ether (specific dielectric constant: 15.76), 1-nonanol (specific dielectric constant: 9.13), toluene (specific dielectric constant: 2.37), propylene glycol monomethyl ether acetate (PM) (specific dielectric constant: 9.4), methyl isobutyl methanol (MIBC) (specific dielectric constant: 10.47), 2,6-dimethyl-4-heptanol (specific dielectric constant: 2.98), 2-ethyl-1-butanol (specific dielectric constant: 12.6), 2-butanone oxime (specific dielectric constant: 2.9), dibutyl ether (specific dielectric constant: 3.33), butyl butyrate (specific dielectric constant: 4.55), 2,6-dimethyl-4-heptanone (specific dielectric constant: 9.82), etc. The organic solvent (S) is preferably selected from at least one of the following groups: methanol (specific dielectric constant: 33), diethylene glycol monobutyl ether (BDG) (specific dielectric constant: 13.70), polyethylene glycol (PE) (specific dielectric constant: 12.71), benzyl alcohol (specific dielectric constant: 12.70), 2-heptanone (specific dielectric constant: 11.74), butanediol acetate (specific dielectric constant: 8.66), tributanol (specific dielectric constant: 12.5), 1-octanol (specific dielectric constant: 10.21), and isobutanol (specific dielectric constant: 18.22). More preferably, it is selected from at least one of the following groups: benzyl alcohol (specific dielectric constant: 12.70) and isobutanol (specific dielectric constant: 18.22).

[0033] Furthermore, the Hansen solubility parameter (dP) of the organic solvent (S) is preferably 0-16, more preferably 0-15, and even more preferably 0-14. If the Hansen solubility parameter (dP) of the organic solvent (S) is within the above-mentioned suitable range, the water repellency of the metal surface can be easily improved.

[0034] In this embodiment, one organic solvent (S) may be used alone, or two or more may be used. In addition, the specific dielectric constant of organic solvents (S) can be measured using commercially available liquid dielectric measuring devices (such as the "Rufuto Model 871" manufactured by Nihon Rufuto Co., Ltd.).

[0035] ·water The surface treatment agent of this embodiment may also contain water to further enhance water repellency and increase the contact angle. The water may contain trace amounts of unavoidable contaminants. The water used in the surface treatment agent of this embodiment is preferably purified water such as distilled water, ion-exchanged water, and ultrapure water, and more preferably ultrapure water commonly used in semiconductor manufacturing. In the surface treatment agent of this embodiment, the water content is preferably 0.01 to 25% by mass, more preferably 0.03 to 20% by mass, and even more preferably 0.05 to 15% by mass. When the water content is within the aforementioned suitable range, compound (P) is more easily adsorbed onto areas containing metal surfaces, thus improving the selectivity of the surface treatment agent for these surfaces. Furthermore, it more easily enhances the water repellency of the surface treatment agent, thereby increasing the contact angle.

[0036] The surface treatment agent of this embodiment contains a compound (P) represented by the general formula (P-1) and an organic solvent (S) with a specific dielectric constant of 35 or less. Compound (P) is a phosphonic acid or a derivative thereof. The phosphonic acid site [-P(=O)(OR 2)(OR 3)] of compound (P) is hydrophilic, and the alkyl chain site (R 1) is hydrophobic. Therefore, in methods for treating surfaces comprising two or more regions, and specifically adjacent regions within those two or more regions where the materials differ, the phosphonic acid site of compound (P) functions as an adsorption group, while the alkyl chain site functions as a hydrophobic group. Thus, compound (P) functions as a material for forming a self-assembled monolayer (hereinafter referred to as a "SAM agent"). On the other hand, organic solvents (S) have a dielectric constant of less than 35 and low polarity. Therefore, among compounds (P) in organic solvents (S), only the phosphonic acid site exhibits high reactivity and strong adsorption to metal surfaces. Furthermore, the surface treatment agent of this embodiment is suitable for surfaces that have already been pretreated with an oxidizing agent. In this pretreatment, the natural oxide film on the metal surface is removed, and hydroxyl groups are imparted to the surface. The above effects complement each other. It is speculated that the surface treatment agent of this embodiment can shorten the processing time in the method of treating a substrate with a surface containing two or more areas of different materials.

[0037] Furthermore, the surface treatment agent of this embodiment is particularly suitable for field-selective film formation methods on substrate surfaces using the ALD method because it has high selectivity, especially for areas containing metal surfaces.

[0038] <Type 2: Surface Treatment Method> The second aspect of the surface treatment method of the present invention is a surface treatment method for a substrate having a surface comprising two or more regions of different materials, and at least one of the two or more aforementioned regions containing a metal surface. The method is characterized by pre-treating the aforementioned surface with an oxidizing agent and exposing it to a surface treatment agent as described in the first aspect.

[0039] In the surface treatment method of this embodiment, the aforementioned surface includes two or more regions, at least one of the two or more aforementioned regions contains a metal surface, and the materials are different from each other. Through the reaction of the aforementioned compound (P) with the two or more aforementioned regions, the contact angles of adjacent regions among the two or more aforementioned regions are made different from each other.

[0040] The second type of surface treatment method involves a substrate surface comprising two or more regions, at least one of which contains a metal surface, and adjacent regions of the two or more regions having different materials.

[0041] Among the two or more fields mentioned above, the field that tends to have an increased water contact angle (preferably a decreased surface free energy) compared to another field includes a field that contains at least one element selected from the group consisting of tungsten (W), cobalt (Co), aluminum (Al), aluminum oxide (Al₂O₃), titanium nitride (TiN), tantalum nitride (TaN), nickel (Ni), ruthenium (Ru), and copper (Cu). Preferably, it contains at least one element selected from the group consisting of tungsten, ruthenium, copper, and cobalt; more preferably, it contains at least one element selected from the group consisting of tungsten and ruthenium. Among the two or more fields mentioned above, the field that tends to have a smaller water contact angle (preferably an increased surface free energy) compared to another field can be cited as a field that includes at least one of the following: silicon (Si), silicon nitride (SiN), silicon oxide (Ox), germanium (Ge), silicon germanium (SiGe), tetraethoxysilane (TEOS), low-k materials, and interlayer insulating films (ILD).

[0042] "The surface of the substrate" refers to the surface of inorganic and organic patterns disposed on the substrate, in addition to the surface of the substrate itself, as well as the surface of inorganic or organic layers that have not been patterned. An inorganic pattern on a substrate is exemplified by a mask created by etching the surface of an inorganic layer on the substrate using a photoresist method, followed by etching to form the pattern. Inorganic layers, besides the substrate itself, include oxide films of elements constituting the substrate, films or layers of inorganic materials such as SiN, Ox, W, Co, TiN, TaN, Ge, SiGe, Al, Al₂O₃, Ni, Ru, Cu, tetraethoxysilane (TEOS), Low-k materials, and interlayer insulating films (ILDs) formed on the substrate surface. This type of film or layer is not particularly limited, but includes, for example, films or layers of inorganic materials formed during the fabrication of semiconductor devices.

[0043] Organic patterns disposed on a substrate include, for example, resin patterns formed on a substrate using photoresist or the like through photolithography. Such organic patterns can be formed, for example, by forming an organic layer of photoresist film on the substrate and then exposing and developing this organic layer using a photomask. The organic layer can also be an organic layer disposed on the surface of a laminate film disposed on the surface of the substrate, in addition to the surface of the substrate itself. This type of organic layer is not particularly limited; examples include organic films disposed during the fabrication of semiconductor devices for etching and masking.

[0044] In this embodiment, the substrate surface includes a first region containing a metal surface and a second region with a different material from the first region and adjacent to the first region. In this case, the "adjacent region" refers to the first region and the second region. Therefore, the first domain and the second domain may be divided into multiple domains, or they may not be divided into multiple domains.

[0045] Examples of the first and second domains include, for instance, the first domain being the surface of the substrate itself and the second domain being the surface of the inorganic layer formed on the surface of the substrate, or the first domain being the surface of the first inorganic layer formed on the surface of the substrate and the second domain being the surface of the second inorganic layer formed on the surface of the substrate. Similarly, examples of forming an organic layer instead of forming these inorganic layers can also be cited.

[0046] The first field is defined as the surface of the substrate itself, and the second field is defined as the surface of the inorganic layer formed on the surface of the substrate. Based on the viewpoint of selectively improving hydrophobicity between two or more adjacent fields of different materials on the substrate surface to improve the contact angle difference of water, it is preferable to define the surface of at least one substrate selected from the group consisting of Si substrate, SiN substrate, Ox substrate, TiN substrate, TaN substrate, Ge substrate, SiGe substrate, TEOS, Low-k material and ILD as the first field, and the second field is defined as the surface of the inorganic layer formed on the surface of the aforementioned substrate, which includes at least one of the group consisting of W, Co, Al, Ni, Ru and Cu.

[0047] Furthermore, regarding the configuration where the surface of the first inorganic layer formed on the surface of the substrate is the first region and the surface of the second inorganic layer formed on the surface of the substrate is the second region, based on the viewpoint of selectively enhancing hydrophobicity between two or more adjacent regions of different materials on the substrate surface to increase the contact angle difference of water, it is preferable to have the surface of a first inorganic layer formed on the surface of any substrate (e.g., a Si substrate) containing at least one of the following materials: SiN, Ox, TiN, TaN, Ge, SiGe, TEOS, Low-k materials, and ILD, as the first region, and the surface of a second inorganic layer formed on the surface of the aforementioned substrate containing at least one of the following materials: W, Co, Al, Ni, Ru, and Cu, as the second region.

[0048] (The substrate surface contains three or more areas) In this embodiment, when the substrate surface includes three or more regions, the substrate surface includes a first region containing a metal surface, a second region with a different material from the first region and adjacent to the first region, and a third region with a different material from the second region and adjacent to the second region. In this case, "adjacent regions" can be the first region and the second region (i.e., adjacent regions) or the first region and the third region (i.e., regions separated by a middle). Furthermore, when the materials of the first field and the third field are different (i.e., both the first field and the third field contain metal surfaces), the "adjacent fields" become the first field and the second field or the second field and the third field (i.e., adjacent fields). Therefore, the first, second, and third domains may be divided into multiple domains or not divided into multiple domains. Examples of the first, second, and third domains include, for instance, a domain where the surface of the substrate itself is the first domain, the surface of the first inorganic layer formed on the surface of the substrate is the second domain, and the surface of the second inorganic layer formed on the surface of the substrate is the third domain. Similarly, examples can be given of forming an organic layer instead of these inorganic layers. Furthermore, examples can also be given of both inorganic and organic layers, such as those formed by replacing only one of the second or third inorganic layers with an organic layer. Based on the viewpoint of selectively enhancing hydrophobicity between two or more adjacent regions of different materials on the substrate surface to increase the contact angle difference of water, it is preferable to have the surface of any substrate (e.g., a Si substrate) itself as the first region, the surface of the substrate containing at least one of the first inorganic layers selected from the group consisting of SiN, Ox, TiN, TaN, Ge, SiGe, TEOS, Low-k materials and ILD as the second region, and the surface of the substrate containing at least one of the second inorganic layers selected from the group consisting of W, Co, Al, Ni, Ru and Cu as the third region. In this embodiment, the same approach can also be applied to cases where the substrate surface includes a fourth or more regions. The upper limit of the number of areas with different materials is not particularly limited as long as it does not impair the effect of the present invention. For example, it can be 7 or less or 6 or less, typically 5 or less.

[0049] (Preprocessing) In this embodiment, the oxidant used for pretreatment of the surface to be treated (the oxidant for pretreatment) is the same as that used in the first embodiment. From the viewpoint of improving the water repellency of the surface to be treated, the oxidant for pretreatment is preferably selected from at least one of the groups consisting of hydrogen peroxide and perhalic acids. Furthermore, selecting at least one of the groups consisting of hydrogen peroxide and perhalic acids is also preferable from the viewpoint that it can avoid damaging metal oxides such as SiO2 and Al2O3 when they coexist on the surface to be treated.

[0050] In this embodiment, the pretreatment temperature is not particularly limited, typically 10~35℃, preferably 15~30℃, and even more preferably 20~25℃. If the pretreatment temperature is within the above-mentioned suitable range, it is easy to remove the natural oxide film on the metal surface and to impart hydroxyl groups to the metal surface.

[0051] Furthermore, in this embodiment, the pretreatment processing time is not particularly limited, typically 10 seconds to 10 minutes, preferably 20 seconds to 5 minutes, and even more preferably 30 seconds to 3 minutes. If the pretreatment temperature is within the above-mentioned suitable range, it is easy to remove the natural oxide film on the metal surface and to impart hydroxyl groups to the metal surface.

[0052] (exposure) Methods for exposing the surface of a substrate to a surface treatment agent include applying a surface treatment agent (typically a liquid surface treatment agent) containing a solvent to the surface of the substrate by means such as dipping, spin coating, roller coating, and doctor blade coating. The exposure temperature is, for example, between 10°C and 90°C, preferably between 20°C and 80°C, more preferably between 20°C and 70°C, and even more preferably between 20°C and 65°C. The exposure time, based on the viewpoint of selectively improving the hydrophobicity between two or more adjacent areas of different materials on the substrate surface, is preferably 20 seconds or more, more preferably 30 seconds or more, and even more preferably 45 seconds or more. The upper limit of the above exposure time is not particularly limited, but it is preferably less than 1 hour, more preferably less than 30 minutes, and even more preferably less than 15 minutes. After the above exposure, washing (e.g., washing with water, surfactant rinsing solution, etc.) and / or drying (drying with nitrogen blowing, etc.) may be carried out as needed. For example, the cleaning process caused by the cleaning solution on the surface of the substrate with inorganic or organic patterns can directly use the cleaning solution that has been used for cleaning the inorganic or organic patterns. For inorganic patterns, SPM (sulfuric acid and hydrogen peroxide water) and APM (ammonia and hydrogen peroxide water) can be used; for organic patterns, water and surfactant rinsing solution can be used. Alternatively, the dried substrate can be subjected to additional heat treatment at temperatures between 100°C and 300°C, depending on the requirements.

[0053] Through the above exposure, compounds (P) can be selectively adsorbed according to the material properties of each area on the substrate surface. The contact angle between the substrate surface exposed to the surface treatment agent and water can be, for example, 60° or more, preferably 80° or more, and even more preferably 85° or more. The upper limit of the contact angle mentioned above is not particularly limited, but is, for example, below 140°, typically below 130°.

[0054] The surface treatment method of this embodiment selectively enhances hydrophobicity in two or more adjacent areas on the substrate surface by exposing different materials, thereby making the water contact angles different from each other. The water contact angle difference between the two or more adjacent areas is not particularly limited as long as it does not impair the effect of the present invention, and for example, it can be 10° or more. From the viewpoint of selectively improving the hydrophobicity between the two or more adjacent areas, the water contact angle difference is preferably 20° or more, more preferably 30° or more, and even more preferably 40° or more. The upper limit of the contact angle difference is not particularly limited as long as it does not impair the effect of the present invention. For example, it is 80° or less or 70° or less, typically 60° or less.

[0055] <Type 3: Region-selective film deposition method on substrate> Next, the method of selectively depositing film on a substrate using the second type of surface treatment method will be explained. In this embodiment, the field-selective film formation method on the substrate includes: treating the surface of the substrate by the surface treatment method of the second embodiment described above, and forming a film on the surface of the surface-treated substrate by atomic layer deposition (ALD), wherein the deposition amount of the film material is selectively different in the field.

[0056] As a result of the surface treatment caused by the method of the second aspect described above, the water contact angle (preferably surface free energy) between the two or more areas becomes different. In this aspect, the areas on the substrate surface where the material deposited to form the film can be selectively different between the two or more areas. Specifically, it is preferable that the water contact angle between the two or more regions becomes larger than that between other regions (preferably where the surface free energy is smaller) in the regions where the film-forming material becomes less likely to be adsorbed (preferably chemisorbed) onto the substrate surface due to the ALD method. As a result, the amount of film-forming material deposited varies between the two or more regions, making the amount of film-forming material deposited on the substrate selectively different in the regions. Examples of chemisorption include chemisorption with hydroxyl groups.

[0057] Among the two or more of the above-mentioned areas, there is a tendency for the water contact angle to be greater than (preferably for the surface free energy to be less than) that of the other areas. Examples of such areas include at least one of the groups selected from W, Co, Al, Ni, Ru and Cu. Among the two or more of the above-mentioned fields, there is a tendency for the water contact angle to be smaller (preferably the surface free energy to be higher) than that of other fields. Examples of such fields include at least one of the following groups: Si, Al₂O₃, SiN, Ox, TiN, TaN, Ge, SiGe, TEOS, Low-k materials and ILD.

[0058] (Film formation induced by ALD method) The film formation method resulting from the ALD method is not particularly limited, but it is preferred to form a thin film by adsorption (preferably chemisorption) of at least two gaseous reactants (hereinafter referred to as "precursor gases"). Specifically, a method may be given as including the following steps (a) and (b), and repeating the following steps (a) and (b) at least once (1 cycle) until the desired film thickness is obtained. (a) The step of exposing the substrate with the surface treatment achieved by the method of the second aspect described above to a pulse of the first precursor gas and (b) Following step (a) above, the step of exposing the substrate to a pulse of the second precursor gas.

[0059] The process may include a plasma treatment step, a step of removing or purging the first precursor gas and its reactants by means of a carrier gas, a second precursor gas, etc., after step (a) and before step (b) above. After step (b) above, the process may or may not include plasma treatment steps, or steps to remove or expel the second precursor gas and its reactants by means of a carrier gas, etc. Inert gases such as nitrogen, argon, and helium can be used as carrier gases.

[0060] Each pulse in each cycle and each layer formed is preferably self-controlled, and each layer formed is preferably a single atomic layer. The thickness of the aforementioned single-atom layer can be defined as, for example, less than 5 nm, preferably less than 3 nm, more preferably less than 1 nm, and even more preferably less than 0.5 nm.

[0061] Examples of the first precursor gases include organometallic compounds, metal halides, and metal oxide halides. Specifically, examples include pentaethoxytantalum, tetra(dimethylamino)titanium, penta(dimethylamino)tantalum, tetra(dimethylamino)zirconium, tetra(dimethylamino)hafnium, tetra(dimethylamino)silane, copper hexafluoroacetoacetone vinyltrimethylsilane, Zn(C₂H₅)₂, Zn(CH₃)₂, TMA (trimethylammonium), TaCl₅, WF₆, WOCl₄, CuCl, ZrCl₄, AlCl₃, TiCl₄, SiCl₄, and HfCl₄.

[0062] The second precursor gas can be any precursor gas that can decompose the first precursor or remove the ligands of the first precursor. Specifically, examples include H₂O, H₂O₂, O₂O₃, NH₃, H₂S, H₂Se, PH₃, AsH₃, C₂H₄, or Si₂H₆.

[0063] The exposure temperature in step (a) is not particularly limited, for example, above 100°C and below 800°C, preferably above 150°C and below 650°C, more preferably above 180°C and below 500°C, and even more preferably above 200°C and below 375°C.

[0064] The exposure temperature in step (b) is not particularly limited, and temperatures that are substantially equal to or higher than the exposure temperature in step (a) can be cited. The films formed by the ALD method are not particularly limited, and examples include films containing pure elements (e.g., Si, Cu, Ta, W), films containing oxides (e.g., SiO 2, GeO 2, HfO 2, ZrO 2, Ta 2O 5, TiO 2, Al 2O 3, ZnO, SnO 2, Sb 2O 5, B 2O 3, In 2O 3, WO 3), films containing nitrides (e.g., Si 3N 4, TiN, AlN, BN, GaN, NbN), films containing carbides (e.g., SiC), films containing sulfides (e.g., CdS, ZnS, MnS, WS 2, PbS), films containing selenides (e.g., CdSe, ZnSe), films containing phosphides (GaP, InP), films containing arsenides (e.g., GaAs, InAs), or mixtures thereof. [Example]

[0065] The present invention will be described in more detail below by way of examples, but the present invention is not limited to these examples.

[0066] [Examples 1-25, Comparative Examples 1-3] Octadecylphosphonic acid was mixed with the organic solvents (S) shown in Tables 1-2 to prepare the surface treatment agents of each example into saturated solutions at room temperature.

[0067] <Surface Treatment (1)> Using the obtained surface treatment agents, the surface treatment of the W substrate is performed according to the following methods.

[0068] • Preprocessing The substrate was pretreated by immersing it in a 3.6% (w / w) H₂O₂ aqueous solution at 25°C for 1 minute. After the pretreatment, the substrate was washed with ion-exchanged distilled water for 1 minute. The washed substrate was then dried using a nitrogen gas stream.

[0069] Surface treatment The dried substrate was immersed in the surface treatment agent shown in Tables 1-2 to perform surface treatment. The surface-treated substrate was then washed with isopropanol for 1 minute, followed by rinsing with ion-exchange distilled water for 1 minute. The washed substrate was then dried with a nitrogen gas stream to obtain the surface-treated substrate.

[0070] <Determination of the contact angle of water (1)> The water contact angle was measured on each substrate after the above surface treatment. 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 a surface-treated substrate, and the contact angle was measured 2 seconds after the drop. The results are shown in Tables 1 and 2 below.

[0071]

[0072]

[0073] In Tables 1 and 2, each abbreviation has the following meaning. BDG: Diethylene glycol monobutyl ether PE: Propylene Glycol Monomethyl Ether EL: Ethyl lactate PM: Propylene glycol monomethyl ether acetate MIBC: Methyl isobutyl alcohol

[0074] The results shown in Tables 1-2 confirm that if the surface treatment agent of Examples 1-25 is used, the contact angle of the W substrate can be increased to more than 70° under surface treatment conditions of less than 60° and less than 10 minutes.

[0075] (Example 26) 0.05% by mass of octadecylphosphonic acid was mixed with propylene glycol monomethyl ether to prepare a surface treatment agent. Using the obtained surface treatment agent, perform surface treatment of the W substrate according to the following method.

[0076] • Preprocessing The substrate was pretreated by immersing it in a 3.6% (w / w) H₂O₂ aqueous solution at 25°C for 1 minute. After the pretreatment, the substrate was washed with ion-exchanged distilled water for 1 minute. The washed substrate was then dried using a nitrogen gas stream.

[0077] Surface treatment The dried substrate is immersed in a surface treatment agent at 60°C for 10 minutes to perform surface treatment. The surface-treated substrate is then washed with isopropanol for 1 minute, followed by rinsing with distilled water via ion exchange for 1 minute. The washed substrate is then dried with a nitrogen gas stream to obtain a surface-treated substrate.

[0078] (Example 27) Except that, in the pretreatment, a 0.5% by mass H₅IO₆ aqueous solution was used instead of a 3.6% by mass H₂O₂ aqueous solution, the surface treatment of the W substrate was performed in the same manner as in Example 26.

[0079] (Comparative Example 4) Except that in the pretreatment, hydrofluoric acid with a concentration of 0.5% by mass was used instead of H2O2 aqueous solution with a concentration of 3.6% by mass, the surface treatment of the W substrate was carried out in the same manner as in Example 26.

[0080] (Comparative Example 5) Except for the absence of pretreatment, the surface treatment of the W substrate was performed in the same manner as in Example 26. <Determination of the contact angle of water (2)> For each of the surface-treated substrates of Examples 26, 27, Comparative Example 4, and Comparative Example 5, the water contact angle was measured in the same manner as in the <Determination of Water Contact Angle (1)> described above. The results are shown in Table 3 below.

[0081]

[0082] The results shown in Table 3 confirm that, in Examples 26 and 27, a surface treatment at 60°C for 10 minutes can increase the contact angle of the W substrate to over 60°.

[0083] (Example 28) 0.05% by mass of octadecylphosphonic acid was mixed with benzyl alcohol to prepare a surface treatment agent. Using the obtained surface treatment agent, perform surface treatment on the Ru substrate according to the following method.

[0084] • Preprocessing Each substrate was pretreated by immersing it in a 0.5% (w / w) H₅IO₆ aqueous solution at 25°C for 1 minute. After the pretreatment, the substrates were washed with ion-exchanged distilled water for 1 minute. The washed substrates were then dried using a nitrogen gas stream.

[0085] Surface treatment The dried substrates were immersed in a surface treatment agent at 60°C for 10 minutes to perform surface treatment. The surface-treated substrates were then washed with isopropanol for 1 minute, followed by rinsing with distilled water via ion exchange for 1 minute. The washed substrates were then dried with a nitrogen gas stream to obtain the surface-treated substrate.

[0086] (Comparative Example 6) Except that isopropanol was used instead of 0.5% by mass H₅IO₆ aqueous solution in the pretreatment, the Ru substrate was surface treated in the same manner as in Example 28.

[0087] (Comparative Example 7) Except that, in the pretreatment, 0.5% hydrofluoric acid was used instead of 0.5% H₅IO₆ aqueous solution, the surface treatment of the Ru substrate was performed in the same manner as in Example 28.

[0088] <Determination of the contact angle of water (3)> For each of the surface-treated substrates of Example 28, Comparative Example 6, and Comparative Example 7, the water contact angle was measured in the same manner as in the above <Determination of Water Contact Angle (1)>. The results are shown in Table 4 below.

[0089]

[0090] The results shown in Table 4 confirm that, in Example 28, a surface treatment at 60°C for 10 minutes can increase the contact angle of the Ru substrate to over 85°.

[0091] (Experimental Example 1-1) The W substrate was surface-treated by immersing it in a 3.6% (w / w) H₂O₂ aqueous solution at 25°C for 1 minute. After the above pretreatment, the substrate was washed with ion-exchanged distilled water for 1 minute. The washed substrate was then dried using a nitrogen gas flow.

[0092] (Experimental Examples 1-2) Except for using a 0.5% by mass H₅IO₆ aqueous solution instead of a 3.6% by mass H₂O₂ aqueous solution in Experimental Example 1-1, the surface treatment of the substrate was performed in the same manner as in Experimental Example 1-1.

[0093] (Experimental Examples 1-3) Except for the use of 0.5% hydrofluoric acid instead of 3.6% H₂O₂ aqueous solution in Test Example 1-1, the surface treatment of the substrate was performed in the same manner as in Test Example 1-1.

[0094] (Analysis of the surface condition of the substrate) The surface morphology of each substrate in Examples 1-1 to 1-3 and the untreated W substrate (Reference Example 2) was analyzed by X-ray photoelectron spectroscopy (XPS). The analysis results are shown in Figure 1.

[0095] The results shown in Figure 1 confirm that the untreated substrate of Reference Example 2 contains W and WO 3. On the other hand, it was confirmed that the WO3 content of the substrates after surface treatment (pretreatment) in Test Examples 1-1 and 1-2 was reduced. Furthermore, it was confirmed that the changes in WO3 of the substrate system after surface treatment (pretreatment) in Test Examples 1-3 were minimal.

[0096] (Experimental Example 2-1) The SiO2 or Al2O3 substrate was surface-treated by immersing it in a 3.6% (w / w) H2O2 aqueous solution at 25°C for 1 minute. After the above pretreatment, the substrate was washed with ion-exchange distilled water for 1 minute. The washed substrate was then dried using a nitrogen gas flow.

[0097] (Experimental Example 2-2) Except for using a 0.5% by mass H₅IO₆ aqueous solution instead of a 3.6% by mass H₂O₂ aqueous solution in Experiment 2-1, the surface treatment of the substrate was performed in the same manner as in Experiment 2-1.

[0098] (Experimental Example 2-3) Except for the use of 0.5% hydrofluoric acid instead of 3.6% H₂O₂ aqueous solution in Experiment 2-1, the surface treatment of the substrate was performed in the same manner as in Experiment 2-1.

[0099] (Evaluation of substrate damage caused by pretreatment) The film loss (etching amount) of the surface-treated substrates in Test Examples 2-1, 2-2, and 2-3 after immersion at 25°C for 15 minutes was measured using a resistivity meter VR-250 (manufactured by Kokusai Electric Semiconductor Service Co., Ltd.). The results are shown in Table 5.

[0100]

[0101] The results shown in Table 5 confirm that, in Test Examples 2-1 and 2-2, the SiO2 substrate and the Al2O3 substrate hardly dissolved due to the surface treatment (pretreatment).

[0102] The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications may be made to the structure without departing from the spirit of the present invention. The present invention is not limited by the foregoing description, but only by the appended claims.

Claims

1. A surface treatment method for a substrate having two or more regions of different materials, wherein at least one of the two or more regions contains a surface of at least one metal selected from the group consisting of tungsten and ruthenium, characterized by comprising pretreatment of the surface by immersion in periodic acid (H5IO6) at 10-35°C for 10 seconds to 10 minutes, and exposing the pretreated surface to a surface treatment agent at 10°C to 90°C for 20 seconds to 1 hour, wherein the surface treatment agent contains a compound (P) represented by the following general formula (P-1), and an organic solvent (S) with a specific dielectric constant of 35 or less, R1-P(=O)(OR2)(OR3)... (P-1) [wherein, R1 is a straight-chain or branched alkyl group, a straight-chain or branched fluoroalkyl group, or an aromatic hydrocarbon group that may have substituents, and R2 and R3 are, respectively, hydrogen atoms, straight-chain or branched alkyl groups, straight-chain or branched fluoroalkyl groups, or aromatic hydrocarbon groups that may have substituents].

2. A method for selectively depositing a film on a substrate surface, comprising treating the aforementioned surface of the substrate by a surface treatment method as described in claim 1, and forming a film on the surface of the substrate prior to surface treatment by atomic layer deposition, wherein the deposition amount of the material in the aforementioned film is selectively different in a specific region.

Images