Surface treatment agent, surface treatment method, and region-selective film formation method on substrate surface

Abstract

To provide a surface treatment agent that can shorten treatment time in a method for treating a substrate having a surface including two or more regions having different qualities of material from each other, a surface treatment method using the surface treatment agent, and a region-selective film forming method of a substrate surface to which the surface treatment method is applied.SOLUTION: A surface treatment agent is used for treating a substrate that has a surface including two or more regions having different qualities of material from each other, in which at least one region of the two or more regions contains a metallic surface, and is pre-treated by oxidizer. The surface treatment agent contains a compound (P) expressed by the general formula (P-1) and organic solvent (S) having the dielectric constant of 35 or less (in the formula, R1 denotes alkyl group or the like. R2 and R3 denote hydrogen atom or alkyl group or the like). R1-P(=O)(OR2)(OR3)...(P-1)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a surface treatment agent, a surface treatment method, and a method for selectively forming a film on a region of a substrate surface. [Background technology]

[0002] In recent years, there has been an increasing trend toward higher integration and miniaturization of semiconductor devices, and organic patterns used as masks and inorganic patterns fabricated by etching processes are becoming increasingly finer, which requires film thickness control at the atomic layer level. Atomic layer deposition (ALD) is a well-known method for forming thin films on a substrate at the atomic layer level. Compared to conventional chemical vapor deposition (CVD) methods, ALD offers superior step coverage and film thickness control.

[0003] The ALD method is a thin-film formation technology in which two types of gases, each containing the same element as the film to be formed, are alternately supplied onto a substrate, and a thin film is formed on the substrate in atomic layer units, repeatedly, to form a film of the desired thickness. In the ALD method, while the source gas is being supplied, only one or a few layers of the source gas components are adsorbed onto the substrate surface, and excess source gas does not contribute to growth; this utilizes the growth's self-limiting function. For example, when forming an Al2O3 film on a substrate, a source gas consisting of TMA (TriMethyAlUminum) and an oxidizing gas containing O are used. When forming a nitride film on a substrate, a nitriding gas is used instead of the oxidizing gas.

[0004] In recent years, attempts have been made to form a film selectively on a substrate surface using the ALD method (see Non-Patent Documents 1 and 2). Accordingly, there is a demand for substrates whose surfaces are modified in a selective manner so that they can be suitably applied to a method for selectively depositing a film on a substrate by the ALD method. In film formation, the use of ALD is expected to enable atomic layer level film thickness control, step coverage, and miniaturization of patterning. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] J.Phys.Chem. C 2014,118,10957-10962 [Non-patent document 2] ACS NANO Vol.9,No.9,8710-8717(2015) Summary of the Invention [Problem to be solved by the invention]

[0006] However, the methods described in Non-Patent Documents 1 and 2 have the problem that, since the substrate surface is modified in a selective manner, it takes a long time to modify the surface depending on the type of substrate.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a surface treatment agent that can shorten the treatment time in a method for treating a substrate having a surface including two or more regions made of different materials, a surface treatment method using the surface treatment agent, and a method for region-selectively forming a film on a substrate surface to which the surface treatment method is applied. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following configuration.

[0009] A first aspect of the present invention is a surface treatment agent used to treat a substrate having a surface including two or more regions made of different materials, at least one of the two or more regions containing a metal surface, the substrate having been pretreated with an oxidizing agent, the surface treatment agent comprising a compound (P) represented by the following general formula (P-1) and an organic solvent (S) having a relative dielectric constant of 35 or less: R1 -P(=O)(OR 2 )(OR 3 )···(P-1) [In the formula, R 1 R is a linear or branched alkyl group, a linear or branched fluorinated alkyl group, or an aromatic hydrocarbon group which may have a substituent. 2 and R 3 are each independently a hydrogen atom, a linear or branched alkyl group, a linear or branched fluorinated alkyl group, or an aromatic hydrocarbon group which may have a substituent.

[0010] A second aspect of the present invention is a surface treatment method for a substrate having a surface including two or more regions made of different materials, at least one of the two or more regions containing a metal surface, the surface treatment method comprising pretreating the surface with an oxidizing agent and exposing the surface to the surface treatment agent of the first aspect.

[0011] A third aspect of the present invention is a method for selectively depositing a film on a substrate surface, comprising treating the surface of the substrate by the surface treatment method of the second aspect and forming a film on the surface-treated substrate by atomic layer deposition, wherein the deposition amount of material for the film is varied selectively in each area. [Effects of the Invention]

[0012] According to the present invention, in a method for treating a substrate having a surface including two or more regions made of different materials, it is possible to provide a surface treatment agent that can shorten the treatment time, a surface treatment method using the surface treatment agent, and a method for region-selectively forming a film on a substrate surface by applying the surface treatment method. [Brief explanation of the drawings]

[0013] [Figure 1] 1 shows the results of XPS analysis of the surface-treated substrate of the test example. DETAILED DESCRIPTION OF THE INVENTION

[0014] <First Aspect: Surface Treatment Agent> A surface treatment agent according to a first aspect of the present invention is a surface treatment agent used to treat a substrate having a surface including two or more regions, at least one of which contains a metal surface, wherein adjacent regions of the two or more regions are made of different materials (hereinafter, sometimes simply referred to as a "surface to be treated"), and which has been pretreated with an oxidizing agent.

[0015] The surface to be treated to which the surface treatment agent of this embodiment is applied includes two or more regions, at least one of which contains a metal surface, and adjacent regions of the two or more regions are made of different materials.

[0016] In this embodiment, when the surface to be treated includes two regions, the surface to be treated includes a first region containing a metal surface and a second region adjacent to the first region and made of a different material from the first region. In such a case, the "adjacent regions" refer to the first region and the second region. Here, each of the first area and the second area may or may not be divided into a plurality of areas.

[0017] In this embodiment, when the surface to be treated includes three or more regions, the surface to be treated includes a first region containing a metal surface, a second region made of a material different from that of the first region and adjacent to the first region, and a third region made of a material different from that of the second region and adjacent to the second region. In this case, the "adjacent regions" may be the first region and the second region (i.e., adjacent regions), or the first region and the third region (i.e., adjacent regions). In addition, when the first region and the third region are made of the same material (i.e., when both the first region and the third region contain metal surfaces), the "adjacent regions" are the first region and the second region, or the second region and the third region (i.e., adjacent regions). Here, each of the first area, the second area, and the third area may or may not be divided into a plurality of areas. In this embodiment, the same concept can be applied to the case where the surface to be treated includes four or more regions. There is no particular upper limit to the number of regions made of different materials as long as the effects of the present invention are not impaired. For example, it is 7 or less, or 6 or less, and typically 5 or less.

[0018] In this embodiment, the metal surface included in the treated surface is not particularly limited, but examples thereof include a metal surface containing at least one selected from the group consisting of tungsten, ruthenium, copper, and cobalt, and also includes a metal surface containing at least one selected from the group consisting of tungsten and ruthenium.

[0019] In this embodiment, the surface to be treated is pretreated with an oxidizing agent. The oxidizing agent used to pretreat the surface to be treated (hereinafter, sometimes referred to as "pretreatment oxidizing agent") is not particularly limited as long as it can remove the native oxide film present on the surface to be treated and impart hydroxyl groups to the surface to be treated. Specific examples of pretreatment oxidizing agents include peroxides such as hydrogen peroxide, perhalogen acids such as periodic acid, and oxoacids such as nitric acid and hypochlorous acid. Of these, at least one pretreatment oxidizing agent selected from the group consisting of hydrogen peroxide and perhalogen acids is preferred from the viewpoint of improving the water repellency of the surface to be treated. Furthermore, at least one pretreatment oxidizing agent selected from the group consisting of hydrogen peroxide and perhalogen acids is also preferred from the viewpoint of treating metal surfaces without damaging inorganic substances such as SiO2 and Al2O3 when these substances are present on the surface to be treated.

[0020] In this embodiment, the pretreatment oxidizing agent may be used alone or in combination of two or more kinds.

[0021] The surface treatment agent of this embodiment contains a compound (P) represented by the following general formula (P-1) and an organic solvent (S) having a relative dielectric constant of 35 or less.

[0022] R 1 -P(=O)(OR 2 )(OR 3)···(P-1) [In the formula, R 1 R is a linear or branched alkyl group, a linear or branched fluorinated alkyl group, or an aromatic hydrocarbon group which may have a substituent. 2 and R 3 are each independently a hydrogen atom, a linear or branched alkyl group, a linear or branched fluorinated alkyl group, or an aromatic hydrocarbon group which may have a substituent.

[0023] ·Compound (P) The compound (P) is a phosphonic acid represented by the general formula (P-1) or a derivative thereof. In the general formula (P-1), R 1 is a linear or branched alkyl group, a linear or branched fluorinated alkyl group, or an aromatic hydrocarbon group which may have a substituent.

[0024] In the general formula (P-1), R 1 The linear or branched alkyl group in the formula (I) preferably has 1 to 45 carbon atoms, more preferably 5 to 40 carbon atoms, and even more preferably 8 to 35 carbon atoms. R 1 Specific examples of the linear or branched alkyl group in the formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, an isotridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an isohexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a heneicosyl group, a docosyl group, and isomers of the above alkyl groups.

[0025] In the general formula (P-1), R 1 Examples of the linear or branched fluorinated alkyl group in the formula (I) include groups in which some or all of the hydrogen atoms of the linear or branched alkyl group have been substituted with fluorine atoms.

[0026] In the general formula (P-1), R 1Examples of the aromatic hydrocarbon group which may have a substituent include a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a biphenyl group, a phenanthryl group, a 2,6-diethylphenyl group, and a 2-methyl-6-ethylphenyl group.

[0027] Among them, R 1 As the alkyl group, a linear or branched alkyl group having 8 or more carbon atoms is preferred, and a dodecyl group or an octadecyl group is more preferred.

[0028] R 2 and R 3 The linear or branched alkyl group, the linear or branched fluorinated alkyl group, or the aromatic hydrocarbon group which may have a substituent in R 1 Examples of the alkyl group include the linear or branched alkyl group, the linear or branched fluorinated alkyl group, and the aromatic hydrocarbon group which may have a substituent. Among them, R 2 and R 3 is preferably a hydrogen atom.

[0029] In this embodiment, the compound (P) may be used alone or in combination of two or more kinds. In the surface treatment agent according to this embodiment, the content of the compound (P) is preferably 0.0001 to 5 mass%, more preferably 0.001 to 4 mass%, even more preferably 0.005 to 3 mass%, and still more preferably 0.008 to 3 mass%, relative to the total mass of the surface treatment agent. When the content of compound (P) is within the above preferred range, compound (P) is easily adsorbed to the region containing the metal surface, and the selectivity of the surface treatment agent for the region containing the metal surface is easily improved.

[0030] Organic solvents (S) The organic solvent (S) is not particularly limited as long as it has a dielectric constant of 35 or less, and examples thereof include methanol (dielectric constant: 33), diethylene glycol monobutyl ether (BDG) (dielectric constant: 13.70), propylene glycol monomethyl ether (PE) (dielectric constant: 12.71), benzyl alcohol (dielectric constant: 12.70), 2-heptanone (dielectric constant: 11.74), butyl glycol acetate (dielectric constant: 8.66), tert-butyl alcohol (dielectric constant: 12.5), 1-octanol (dielectric constant: 10.21), isobutanol (dielectric constant: 18.22), benzotrifluoride (dielectric constant: 9.18), decahydronaphthalene (dielectric constant: 2.16), cyclohexane (dielectric constant: 1.99), decane (dielectric constant: less than 1), and the like. Examples of suitable diisobutyl alcohol include isobutyl alcohol (dielectric constant: 18.22), ethyl lactate (EL) (dielectric constant: 13.22), diethylene glycol monomethyl ether (dielectric constant: 15.76), 1-nonanol (dielectric constant: 9.13), toluene (dielectric constant: 2.37), propylene glycol monomethyl ether acetate (PM) (dielectric constant: 9.4), methyl isobutyl carbinol (MIBC) (dielectric constant: 10.47), 2,6-dimethyl-4-heptanol (dielectric constant: 2.98), 2-ethyl-1-butanol (dielectric constant: 12.6), 2-butanone oxime (dielectric constant: 2.9), n-dibutyl ether (dielectric constant: 3.33), butyl butyrate (dielectric constant: 4.55), and 2,6-dimethyl-4-heptanone (dielectric constant: 9.82). Among these, as the organic solvent (S), at least one selected from the group consisting of methanol (relative dielectric constant: 33), diethylene glycol monobutyl ether (BDG) (relative dielectric constant: 13.70), polyethylene glycol (PE) (relative dielectric constant: 12.71), benzyl alcohol (relative dielectric constant: 12.70), 2-heptanone (relative dielectric constant: 11.74), butyl glycol acetate (relative dielectric constant: 8.66), tert-butyl alcohol (relative dielectric constant: 12.5), 1-octanol (relative dielectric constant: 10.21) and isobutanol (relative dielectric constant: 18.22) is preferred, and at least one selected from the group consisting of benzyl alcohol (relative dielectric constant: 12.70) and isobutanol (relative dielectric constant: 18.22) is more preferred.

[0031] The Hansen solubility parameter (dP) of the organic solvent (S) is preferably from 0 to less than 16, more preferably from 0 to 15, and even more preferably from 0 to 14. When the Hansen solubility parameter (dP) of the organic solvent (S) is within the above preferred range, the water repellency of the metal surface is easily increased.

[0032] In the present embodiment, the organic solvent (S) may be used alone or in combination of two or more kinds. The relative dielectric constant of the organic solvent (S) can be measured using a commercially available liquid dielectric constant measuring device (for example, "Rufuto Model 871" manufactured by Nippon Rufuto Co., Ltd.).

[0033] ·water The surface treatment agent according to this embodiment may contain water to further improve water repellency and thereby improve the contact angle. The water may contain trace components that are inevitably mixed in. The water used in the surface treatment agent according to this embodiment is preferably purified water such as distilled water, ion-exchanged water, or ultrapure water, and more preferably ultrapure water commonly used in semiconductor manufacturing. In the surface treatment agent according to this embodiment, when water is included, the content is preferably from 0.01 to 25 mass %, more preferably from 0.03 to 20 mass %, and even more preferably from 0.05 to 15 mass %. When the water content is within the above-mentioned preferred range, the compound (P) is easily adsorbed to the region containing the metal surface, which makes it easy to improve the selectivity of the surface treatment agent for the region containing the metal surface. In addition, the water repellency of the surface treatment agent is easily improved, which makes it easy to improve the contact angle.

[0034] The surface treatment agent of this embodiment contains a compound (P) represented by general formula (P-1) and an organic solvent (S) having a relative dielectric constant of 35 or less. Compound (P) is a phosphonic acid or a derivative thereof. Compound (P) has a phosphonic acid moiety [—P(═O)(OR 2 )(OR 3 )] is hydrophilic, and the alkyl chain portion (R1 ) is hydrophobic. Therefore, in a method for treating a surface including two or more regions, in which adjacent regions of the two or more regions are made of different materials, the phosphonic acid moiety of compound (P) functions as an adsorptive group, while the alkyl chain moiety functions as a water-repellent group. Therefore, compound (P) functions as a material that forms a self-assembled monolayer (hereinafter referred to as a "SAM agent"). On the other hand, the organic solvent (S) has a relative dielectric constant of 35 or less and low polarity. Therefore, the reactivity of only the phosphonic acid moiety of the compound (P) in the organic solvent (S) increases, and the adsorption force to the metal surface increases. In addition, the surface treatment agent of the present embodiment is applied to a surface to be treated that has been pretreated with a pretreatment oxidizing agent, in which a native oxide film or the like has been removed from the metal surface and hydroxyl groups have been added by the pretreatment. It is presumed that the combination of the above effects makes it possible for the surface treatment agent of this embodiment to shorten the treatment time in a method for treating a substrate having a surface including two or more regions made of different materials.

[0035] Furthermore, the surface treatment agent according to this embodiment has high selectivity to regions (especially) containing metal surfaces, and is therefore particularly suitable for region-selective film formation on substrate surfaces using the ALD method.

[0036] <Second Aspect: Surface Treatment Method> A surface treatment method according to a second aspect of the present invention is a method for treating a substrate having a surface including two or more regions made of different materials, at least one of which contains a metal surface, and includes pretreating the surface with an oxidizing agent and exposing the surface to the surface treatment agent of the first aspect.

[0037] In the surface treatment method according to this embodiment, the surface includes two or more regions, at least one of which contains a metal surface, and adjacent regions of the two or more regions are made of different materials, and the reaction between the compound (P) and the two or more regions causes adjacent regions of the two or more regions to have different contact angles.

[0038] In a surface treatment method according to a second aspect, the substrate surface includes two or more regions, at least one of the two or more regions contains a metal surface, and adjacent regions of the two or more regions are made of different materials.

[0039] Among the two or more regions, an example of a region that tends to have a higher water contact angle (preferably a lower surface free energy) than the other region is a region containing at least one 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). Among these, it is preferable to contain at least one selected from the group consisting of tungsten, ruthenium, copper, and cobalt, and it is more preferable to contain at least one selected from the group consisting of tungsten and ruthenium. Among the two or more regions, the region that tends to have a smaller water contact angle (preferably, a higher surface free energy) than the other region includes a region containing at least one material selected from the group consisting of silicon (Si), silicon nitride (SiN), silicon oxide (Ox), germanium (Ge), silicon germanium (SiGe), tetraethoxysilane (TEOS), low-k material, and interlayer dielectric (ILD).

[0040] The "surface of the substrate" includes the surface of the substrate itself, as well as the surfaces of inorganic and organic patterns provided on the substrate, and the surfaces of unpatterned inorganic or organic layers. An example of an inorganic pattern provided on a substrate is a pattern formed by etching the surface of an inorganic layer present on the substrate using a photoresist method, creating an etching mask on the surface, and then performing an etching process. Examples of inorganic layers include the substrate itself, oxide films of elements constituting the substrate, inorganic films or layers formed on the surface of the substrate, such as SiN, Ox, W, Co, TiN, TaN, Ge, SiGe, Al, Al2O3, Ni, Ru, Cu, tetraethoxysilane (TEOS), low-k materials, and interlayer dielectrics (ILDs). Such films and layers are not particularly limited, but examples thereof include inorganic films and layers formed in the process of manufacturing semiconductor devices.

[0041] Examples of organic patterns provided on a substrate include resin patterns formed on a substrate by photolithography using photoresist or the like. Such organic patterns can be formed, for example, by forming an organic layer, which is a photoresist film, on the substrate, exposing this organic layer through a photomask, and developing it. The organic layer may be an organic layer provided on the surface of the substrate itself, or on the surface of a laminated film provided on the surface of the substrate. Examples of such organic layers include, but are not limited to, organic films provided for etching or forming masks during the process of manufacturing a semiconductor device.

[0042] In this embodiment, the substrate surface includes a first region containing a metal surface and a second region adjacent to the first region and made of a different material from the first region. In this case, the "adjacent regions" refer to the first region and the second region. Here, each of the first area and the second area may or may not be divided into a plurality of areas.

[0043] Examples of the first region and the second region include an embodiment in which the surface of the substrate itself is the first region and the surface of an inorganic layer formed on the surface of the substrate is the second region, an embodiment in which the surface of a first inorganic layer formed on the surface of the substrate is the first region and the surface of a second inorganic layer formed on the surface of the substrate is the second region, etc. Note that similar examples include an embodiment in which an organic layer is formed instead of forming these inorganic layers.

[0044] In an embodiment in which the surface of the substrate itself is the first region and the surface of an inorganic layer formed on the surface of the substrate is the second region, from the viewpoint of selectively improving hydrophobicity and increasing the difference in water contact angle between two or more adjacent regions made of different materials on the substrate surface, a preferred embodiment is one in which the surface of at least one substrate selected from the group consisting of a Si substrate, a SiN substrate, an Ox substrate, a TiN substrate, a TaN substrate, a Ge substrate, a SiGe substrate, TEOS, a low-k material, and an ILD is the first region, and the surface of an inorganic layer formed on the surface of the substrate and containing at least one material selected from the group consisting of W, Co, Al, Ni, Ru, and Cu is the second region.

[0045] In addition, as an embodiment in which the surface of a first inorganic layer formed on the surface of a substrate is the first region and the surface of a second inorganic layer formed on the surface of a substrate is the second region, from the viewpoint of selectively improving hydrophobicity between two or more adjacent regions on the substrate surface made of different materials and thereby improving the difference in water contact angle, a preferred embodiment is one in which the surface of a first inorganic layer formed on the surface of any substrate (e.g., a Si substrate) is the first region and the surface of a second inorganic layer formed on the surface of the substrate is the second region and includes at least one selected from the group consisting of SiN, Ox, TiN, TaN, Ge, SiGe, TEOS, low-k material, and ILD.

[0046] (Substrate surface includes three or more regions) 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 made of a material different from that of the first region and adjacent to the first region, and a third region made of a material different from that of the second region and adjacent to the second region. In this case, the "adjacent regions" may be the first region and the second region (i.e., adjacent regions), or the first region and the third region (i.e., adjacent regions). In addition, when the first region and the third region are made of the same material (i.e., when both the first region and the third region contain metal surfaces), the "adjacent regions" are the first region and the second region, or the second region and the third region (i.e., adjacent regions). Here, each of the first area, the second area, and the third area may or may not be divided into a plurality of areas. Examples of the first, second, and third regions include an embodiment in which the surface of the substrate itself is the first region, the surface of a first inorganic layer formed on the surface of the substrate is the second region, and the surface of a second inorganic layer formed on the surface of the substrate is the third region. Similar embodiments include an embodiment in which an organic layer is formed instead of forming these inorganic layers. Similar embodiments include an embodiment in which only one of the second inorganic layer and the third inorganic layer is replaced with an organic layer, thereby including both an inorganic layer and an organic layer. From the viewpoint of selectively improving the hydrophobicity between two or more adjacent regions made of different materials on the substrate surface and thereby improving the difference in water contact angle, a preferred embodiment is one in which the surface of any substrate (e.g., a Si substrate) itself is defined as the first region, the surface of a first inorganic layer formed on the surface of the substrate and containing at least one selected from the group consisting of SiN, Ox, TiN, TaN, Ge, SiGe, TEOS, a low-k material, and an ILD is defined as the second region, and the surface of a second inorganic layer formed on the surface of the substrate and containing at least one selected from the group consisting of W, Co, Al, Ni, Ru, and Cu is defined as the third region. In this embodiment, the same concept can be applied to the case where the substrate surface includes four or more regions. There is no particular upper limit to the number of regions made of different materials as long as the effects of the present invention are not impaired. For example, it is 7 or less, or 6 or less, and typically 5 or less.

[0047] (Pretreatment) In this embodiment, the oxidizing agent (pretreatment oxidizing agent) used to pretreat the surface to be treated is the same as the pretreatment oxidizing agent in the first embodiment. Among these, at least one pretreatment oxidizing agent selected from the group consisting of hydrogen peroxide and perhalogen acids is preferred from the viewpoint of improving the water repellency of the surface to be treated. Furthermore, at least one pretreatment oxidizing agent selected from the group consisting of hydrogen peroxide and perhalogen acids is also preferred from the viewpoint of not damaging metal oxides such as SiO2 and Al2O3 when they are present on the surface to be treated.

[0048] In this embodiment, the treatment temperature for the pretreatment is not particularly limited, but is typically 10 to 35°C, preferably 15 to 30°C, and more preferably 20 to 25°C. When the treatment temperature for the pretreatment is within the above-mentioned preferred range, it is easy to remove the native oxide film on the metal surface and to provide hydroxyl groups to the metal surface.

[0049] In this embodiment, the processing time for the pretreatment is not particularly limited, but is typically 10 seconds to 10 minutes, preferably 20 seconds to 5 minutes, and more preferably 30 seconds to 3 minutes. When the treatment temperature for the pretreatment is within the above-mentioned preferred range, it is easy to remove the native oxide film on the metal surface and to provide hydroxyl groups to the metal surface.

[0050] (exposure) Examples of a method for exposing the surface of a substrate to a surface treatment agent include a method in which a surface treatment agent (typically a liquid surface treatment agent) which may contain a solvent is applied (e.g., coated) to the surface of the substrate by means of, for example, an immersion method or a coating method such as a spin coating method, a roll coating method, or a doctor blade method. The exposure temperature is, for example, 10°C or higher and 90°C or lower, preferably 20°C or higher and 80°C or lower, more preferably 20°C or higher and 70°C or lower, and even more preferably 20°C or higher and 65°C or lower. The exposure time is preferably 20 seconds or more, more preferably 30 seconds or more, and even more preferably 45 seconds or more, from the viewpoint of selectively improving hydrophobicity between two or more adjacent regions made of different materials on the substrate surface. There is no particular upper limit to the exposure time, but it is preferably 1 hour or less, more preferably 30 minutes or less, and even more preferably 15 minutes or less, for example. After the exposure, washing (for example, washing with water, rinsing with an activator, etc.) and / or drying (rinsing with nitrogen blowing, etc.) may be carried out as necessary. For example, when cleaning the surface of a substrate having an inorganic or organic pattern with a cleaning liquid, cleaning liquids that have conventionally been used for cleaning inorganic or organic patterns can be used as they are. For inorganic patterns, examples include SPM (sulfuric acid / hydrogen peroxide solution) and APM (ammonia / hydrogen peroxide solution), and for organic patterns, examples include water, surfactant rinse, etc. Furthermore, the treated substrate after drying may be additionally subjected to a heat treatment at 100° C. or higher and 300° C. or lower, if necessary.

[0051] By the above exposure, the compound (P) can be adsorbed selectively in each region of the substrate surface depending on the material of each region. The contact angle of the substrate surface with water after exposure to the surface treatment agent can be, for example, 60° or more, preferably 80° or more, and more preferably 85° or more. There is no particular upper limit to the contact angle, but it is, for example, 140° or less, typically 130° or less.

[0052] In the surface treatment method according to this embodiment, since the materials are different between two or more adjacent regions on the substrate surface, the exposure can selectively improve the hydrophobicity between the two or more adjacent regions, thereby making the water contact angles different from each other. The difference in water contact angle between the two or more adjacent regions is not particularly limited as long as it does not impair the effects of the present invention, and may be, for example, 10° or more. From the viewpoint of selectively improving hydrophobicity between the two or more adjacent regions, the difference in water contact angle 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 effects of the present invention, and is, for example, 80° or less or 70° or less, and typically 60° or less.

[0053] <Third Aspect: Region-Selective Film Formation Method on Substrate> Next, a method for selectively depositing a film on a substrate using the surface treatment method according to the second embodiment will be described. In this aspect, the method for region-selectively forming a film on a substrate includes treating the surface of the substrate by the surface treatment method according to the second aspect, and forming a film on the surface-treated surface of the substrate by atomic layer deposition (ALD), thereby varying the deposition amount of material of the film in a region-selective manner.

[0054] As a result of the surface treatment by the method according to the second aspect, the water contact angle (preferably, the surface free energy) differs between the two or more regions, and in this aspect, the deposition amount of the material forming the film can be selectively varied between the two or more regions on the substrate surface. Specifically, in a region where the contact angle of water between the two or more regions is larger than that between the other regions (preferably, where the surface free energy is smaller), the film-forming material formed by the ALD method is less likely to adsorb (preferably chemically adsorb) to the region on the substrate surface, resulting in a difference in the amount of film-forming material deposited between the two or more regions, and it is preferable that the amount of film-forming material deposited differs selectively in regions on the substrate. The chemical adsorption may be chemical adsorption with a hydroxyl group.

[0055] Among the two or more regions, the region that tends to have a larger water contact angle (preferably a smaller surface free energy) than the other region includes a region containing at least one selected from the group consisting of W, Co, Al, Ni, Ru, and Cu. Among the two or more regions, the region that tends to have a smaller water contact angle (preferably, a higher surface free energy) than the other region includes a region that contains at least one material selected from the group consisting of Si, Al2O3, SiN, Ox, TiN, TaN, Ge, SiGe, TEOS, low-k material, and ILD.

[0056] (Film formation by ALD method) Although there are no particular limitations on the film formation method using the ALD method, it is preferable to use a thin film formation method that uses adsorption (preferably chemical adsorption) using at least two gas phase reactive substances (hereinafter simply referred to as "precursor gases"). Specifically, the method includes the following steps (a) and (b), which are repeated at least once (one cycle) until a desired film thickness is obtained. (a) exposing a substrate that has been surface treated by the method according to the second aspect to a pulse of a first precursor gas; and (b) following step (a), exposing the substrate to a pulse of a second precursor gas.

[0057] After the step (a) and before the step (b), a plasma treatment step, a step of removing or purging the first precursor gas and its reactants using a carrier gas, a second precursor gas, etc. may or may not be included. After the step (b), a plasma treatment step, a step of removing or purging the second precursor gas and its reactants with a carrier gas or the like, and the like may or may not be included. Examples of the carrier gas include inert gases such as nitrogen gas, argon gas, and helium gas.

[0058] Preferably, each pulse per cycle and each layer formed is self-limiting, and more preferably, each layer formed is a monolayer. The thickness of the monoatomic 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.

[0059] Examples of the first precursor gas include organic metals, metal halides, and metal oxide halides, and specific examples include tantalum pentaethoxide, tetrakis(dimethylamino)titanium, pentakis(dimethylamino)tantalum, tetrakis(dimethylamino)zirconium, tetrakis(dimethylamino)hafnium, tetrakis(dimethylamino)silane, copper hexafluoroacetylacetonate vinyltrimethylsilane, Zn(C2H5)2, Zn(CH3)2, TMA (trimethylaluminum), TaCl5, WF6, WOCl4, CuCl, ZrCl4, AlCl3, TiCl4, SiCl4, and HfCl4.

[0060] The second precursor gas may be a precursor gas capable of decomposing the first precursor or removing the ligand of the first precursor, such as HO, HO, OO, NH, HS, HS, PH, AsH, CH, or SiH.

[0061] The exposure temperature in step (a) is not particularly limited, but is, for example, 100°C or higher and 800°C or lower, preferably 150°C or higher and 650°C or lower, more preferably 180°C or higher and 500°C or lower, and even more preferably 200°C or higher and 375°C or lower.

[0062] The exposure temperature in step (b) is not particularly limited, but may be a temperature substantially equal to or higher than the exposure temperature in step (a). Films formed by the ALD method are not particularly limited, and examples thereof include films containing pure elements (e.g., Si, Cu, Ta, W), films containing oxides (e.g., SiO2, GeO2, HfO2, ZrO2, Ta2O5, TiO2, Al2O3, ZnO, SnO2, Sb2O5, BO3, In2O3, WO3), films containing nitrides (e.g., Si3N4, TiN, AlN, BN, GaN, NbN), films containing carbides (e.g., SiC), films containing sulfides (e.g., CdS, ZnS, MnS, WS2, PbS), films containing selenides (e.g., CdSe, ZnSe), films containing phosphides (GaP, InP), films containing arsenides (e.g., GaAs, InAs), and mixtures thereof. [Example]

[0063] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0064] [Examples 1 to 25, Comparative Examples 1 to 3] Octadecylphosphonic acid was mixed with an organic solvent (S) shown in Tables 1 and 2 to prepare a surface treatment agent of each example as a saturated solution at room temperature.

[0065] <Surface treatment (1)> Using the surface treatment agent of each example obtained, a W substrate was surface treated according to the following method.

[0066] Pretreatment The substrate was pretreated by immersing it in a 3.6% by mass H2O2 aqueous solution at 25°C for 1 minute. After the pretreatment, the substrate was washed with ion-exchanged distilled water for 1 minute. After washing, the substrate was dried in a nitrogen stream.

[0067] Surface treatment The dried substrate was immersed in the surface treatment agent of each example under the surface treatment conditions shown in Tables 1 and 2 to perform surface treatment. The surface-treated substrate was washed with isopropanol for 1 minute, and then washed with ion-exchanged distilled water for 1 minute. The washed substrate was dried in a nitrogen stream to obtain a surface-treated substrate.

[0068] <Measurement of water contact angle (1)> After the above surface treatment, the water contact angle of each substrate was measured. The contact angle of water was measured using a Dropmaster 700 (manufactured by Kyowa Interface Science Co., Ltd.) by dropping a droplet (2.0 μL) of pure water onto the surface of the surface-treated substrate and measuring the contact angle 2 seconds after the drop. The results are shown in Tables 1 and 2 below.

[0069] [Table 1]

[0070] [Table 2]

[0071] In Tables 1 and 2, the abbreviations have the following meanings: BDG: Diethylene glycol monobutyl ether PE: Propylene glycol monomethyl ether EL: Ethyl lactate PM: Propylene glycol monomethyl ether acetate MIBC: methyl isobutyl carbinol

[0072] From the results shown in Tables 1 and 2, it was confirmed that the surface treatment agents of Examples 1 to 25 could increase the contact angle of the W substrate to 70° or more under surface treatment conditions of 60° C. or less and 10 minutes or less.

[0073] Example 26 A surface treatment agent was prepared by mixing 0.05% by mass of octadecylphosphonic acid with propylene glycol monomethyl ether. Using the obtained surface treatment agent, a W substrate was surface treated according to the following method.

[0074] Pretreatment The substrate was pretreated by immersing it in a 3.6% by mass H2O2 aqueous solution at 25°C for 1 minute. After the pretreatment, the substrate was washed with ion-exchanged distilled water for 1 minute. After washing, the substrate was dried in a nitrogen stream.

[0075] Surface treatment The dried substrate was immersed in a surface treatment agent at 60°C for 10 minutes to perform surface treatment. The surface-treated substrate was then washed with isopropanol for 1 minute, followed by washing with ion-exchanged distilled water for 1 minute. The washed substrate was then dried in a nitrogen stream to obtain a surface-treated substrate.

[0076] Example 27 The surface treatment of the W substrate was carried out in the same manner as in Example 26, except that in the pretreatment, an H5IO6 aqueous solution with a concentration of 0.5 mass % was used instead of the H2O2 aqueous solution with a concentration of 3.6 mass %.

[0077] Comparative Example 4 The surface treatment of the W substrate was carried out in the same manner as in Example 26, except that in the pretreatment, hydrofluoric acid with a concentration of 0.5% was used instead of the H2O2 aqueous solution with a concentration of 3.6 mass %.

[0078] (Comparative Example 5) The surface treatment of the W substrate was carried out in the same manner as in Example 26, except that no pretreatment was carried out. <Measurement of water contact angle (2)> The water contact angle was measured in the same manner as in <Measurement of water contact angle (1)> above for each of the surface-treated substrates of Examples 26, 27, Comparative Examples 4, and 5. The results are shown in Table 3 below.

[0079] [Table 3]

[0080] From the results shown in Table 3, it was confirmed that in Examples 26 and 27, the contact angle of the W substrate could be increased to 60° or more under surface treatment conditions of 60° C. and 10 minutes.

[0081] Example 28 A surface treatment agent was prepared by mixing 0.05% by mass of octadecylphosphonic acid with benzyl alcohol. Using the obtained surface treatment agent, a Ru substrate was surface treated according to the following method.

[0082] Pretreatment Each substrate was pretreated by immersing it in a 0.5% by mass H5IO6 aqueous solution at 25°C for 1 minute. After the pretreatment, the substrate was washed with ion-exchanged distilled water for 1 minute. After washing, the substrate was dried in a nitrogen stream.

[0083] Surface treatment After drying, each substrate was immersed in a surface treatment agent at 60°C for 10 minutes to perform surface treatment. After surface treatment, the substrate was washed with isopropanol for 1 minute, and then washed with ion-exchanged distilled water for 1 minute. The washed substrate was dried in a nitrogen stream to obtain a surface-treated substrate.

[0084] (Comparative Example 6) The surface treatment of the Ru substrate was carried out in the same manner as in Example 28, except that in the pretreatment, isopropanol was used instead of the 0.5 mass % H5IO6 aqueous solution.

[0085] (Comparative Example 7) The surface treatment of the Ru substrate was carried out in the same manner as in Example 28, except that in the pretreatment, hydrofluoric acid with a concentration of 0.5% was used instead of the aqueous H5IO6 solution with a concentration of 0.5% by mass.

[0086] <Measurement of water contact angle (3)> The water contact angle was measured in the same manner as in <Measurement of water contact angle (1)> above for each of the surface-treated substrates of Example 28, Comparative Example 6, and Comparative Example 7. The results are shown in Table 4 below.

[0087] [Table 4]

[0088] From the results shown in Table 4, it was confirmed that in Example 28, the contact angle of the Ru substrate could be improved to 85° or more under surface treatment conditions of 60° C. and 10 minutes.

[0089] (Test Example 1-1) The W substrate was surface-treated by immersing it in a 3.6% by mass H2O2 aqueous solution at 25°C for 1 minute. After the pretreatment, the substrate was washed with ion-exchanged distilled water for 1 minute. After washing, the substrate was dried in a nitrogen stream.

[0090] (Test Example 1-2) The surface treatment of the substrate was carried out in the same manner as in Test Example 1-1, except that an aqueous solution of H5IO6 with a concentration of 0.5 mass % was used instead of the aqueous solution of H2O2 with a concentration of 3.6 mass % in Test Example 1-1.

[0091] (Test Example 1-3) The surface treatment of the substrate was carried out in the same manner as in Test Example 1-1, except that the aqueous H2O2 solution with a concentration of 3.6 mass % was replaced with hydrofluoric acid with a concentration of 0.5%.

[0092] (Analysis of the surface condition of the substrate) The surface conditions of each of the substrates of Test Examples 1-1 to 1-3 and the untreated W substrate (Reference Example 2) were analyzed by X-ray photoelectron spectroscopy (XPS). The analysis results are shown in FIG.

[0093] From the results shown in FIG. 1, it was confirmed that W and WO3 were present in the untreated substrate of Reference Example 2. On the other hand, it was confirmed that the WO3 content of the substrates after the surface treatment (pretreatment) of Test Examples 1-1 and 1-2 was reduced. Furthermore, it was confirmed that the change in WO3 in the substrate after the surface treatment (pretreatment) of Test Example 1-3 was slight.

[0094] (Test Example 2-1) The SiO2 or Al2O3 substrates were surface-treated by immersing them in a 3.6% by mass H2O2 aqueous solution at 25°C for 1 minute. After the pretreatment, the substrates were washed with ion-exchanged distilled water for 1 minute. After washing, the substrates were dried in a nitrogen stream.

[0095] (Test Example 2-2) The surface treatment of the substrate was carried out in the same manner as in Test Example 2-1, except that an aqueous solution of H5IO6 with a concentration of 0.5 mass % was used instead of the aqueous solution of H2O2 with a concentration of 3.6 mass % in Test Example 2-1.

[0096] (Test Example 2-3) The surface treatment of the substrate was carried out in the same manner as in Test Example 2-1, except that the aqueous H2O2 solution with a concentration of 3.6 mass % was replaced with hydrofluoric acid with a concentration of 0.5%.

[0097] (Evaluation of substrate damage due to pre-processing) After the surface treatments of Test Examples 2-1, 2-2, and 2-3, the substrates were immersed at 25°C for 15 minutes, and the amount of film loss (etching amount) was measured using sheet resistance. The sheet resistance was measured using a resistivity meter VR-250 (manufactured by Kokusai Electric Semiconductor Services Co., Ltd.). The results are shown in Table 5.

[0098] [Table 5]

[0099] From the results shown in Table 5, it was confirmed that in Test Examples 2-1 and 2-2, the SiO2 substrate and the Al2O3 substrate were hardly dissolved by the surface treatment (pretreatment).

Claims

1. A surface treatment agent for treating a substrate having a surface including two or more regions made of different materials, at least one of the two or more regions containing a metal surface containing at least one kind selected from the group consisting of tungsten and ruthenium, the substrate having been pretreated with an oxidizing agent containing a perhalogen acid, the surface treatment agent comprising: A compound (P) represented by the following general formula (P-1), an organic solvent (S) having a relative dielectric constant of 35 or less; A surface treatment agent containing R １ -P(=O)(OR ２ )(OR ３ )・・・(P-1) [In the formula, R １ R is a linear or branched alkyl group, a linear or branched fluorinated alkyl group, or an aromatic hydrocarbon group which may have a substituent. ２ and R ３ are each independently a hydrogen atom, a linear or branched alkyl group, a linear or branched fluorinated alkyl group, or an aromatic hydrocarbon group which may have a substituent.

2. A surface treatment method for a substrate having a surface including two or more regions made of different materials, at least one of the two or more regions containing a metal surface containing at least one kind selected from the group consisting of tungsten and ruthenium, comprising: pretreating the surface with an oxidizing agent comprising a perhalogen acid; exposing the pre-treated surface to the surface treatment agent of claim 1. Surface treatment method.

3. treating the surface of the substrate by the surface treatment method according to claim 2; forming a film on the surface of the surface-treated substrate by atomic layer deposition; The method for selectively depositing a film on a substrate surface includes selectively varying the amount of material deposited on the film.

Images