JP7712854B2 - Substrate manufacturing method and coating liquid - Google Patents

Description

The present invention relates to a method for manufacturing a substrate and a coating liquid.

As semiconductor devices become more miniaturized, there is a demand for technology to form fine patterns of 30 nm or less. However, conventional lithography methods are becoming technically difficult due to optical factors, etc.

Therefore, the formation of fine patterns using so-called bottom-up techniques is being considered. Examples of bottom-up techniques include selectively chemically modifying a substrate having fine regions on its surface, forming metal oxide in the unmodified regions of the substrate by ALD (Atomic Layer Deposition) or CVD (Chemical Vapor Deposition), and then removing the chemical modification to form a pattern on the substrate (WO 2019/023001).

International Publication No. 2019/023001

WO 2019/023001 discloses a method that includes exposing a substrate having a first surface with hydrogen termination and a second surface with hydroxide termination to a nitriding agent to form an amine-terminated first surface, and exposing the amine-terminated first surface to a blocking molecule to form a blocking layer on the first surface.

In the above method, a blocking layer is selectively formed on the amine-terminated surface by immersing the substrate in a solution of undecanal in DMSO. At this time, it is believed that the Si-NH2 _groups on the substrate surface react with the aldehyde groups of the undecanal (dehydration condensation reaction) to form carbon-nitrogen double bonds. However, this reaction is an equilibrium reaction and is highly susceptible to hydrolysis by water in the solution or air, so it is believed to be difficult to stably form a blocking layer on the substrate by the coating method.

The present invention aims to provide a method for manufacturing a substrate, and _a coating liquid capable of selectively forming, by a coating method, a film that exhibits high blocking performance against metal oxide formation by an ALD method or a CVD method on a substrate having a surface layer including a region including a terminal structure represented by Si-NH2.

The invention made to solve the above problem is a method for manufacturing a substrate, comprising the steps of: applying a coating liquid to a base material having on its surface a first region including a terminal structure represented by Si- _NH2 ; and heating a coating film formed by the coating step, wherein the coating liquid contains a compound having an aromatic ring structure and a functional group that reacts with the terminal structure of the first region to form a carbon-nitrogen double bond.

Another invention made to solve the above problems is a coating liquid used to be applied to a substrate having a surface layer including a first region including a terminal structure represented by Si- _NH2 , the coating liquid containing a compound having an aromatic ring structure and a functional group that reacts with the terminal structure of the first region to form a carbon-nitrogen double bond.

According to the substrate manufacturing method and coating solution of the present invention, a film that exhibits _high blocking performance against metal oxide formation by the ALD method or CVD method can be selectively formed by a coating method on a substrate having a region containing an end structure represented by Si-NH2 on its surface layer.

The manufacturing method and coating liquid for the substrate of the present invention are described in detail below.

<Substrate manufacturing method>
The method for manufacturing the substrate includes a step of applying a coating liquid to a base material having a surface layer including a first region including a terminal structure represented by Si- _NH2 (hereinafter also referred to as a "coating step"), and a step of heating the coating film formed by the coating step (hereinafter also referred to as a "heating step").

The method for manufacturing a substrate, which has the above _- mentioned configuration, can selectively form, by a coating method, a film that exhibits high blocking performance against metal oxide formation by an ALD method or a CVD method on a substrate having a surface layer including a region including a terminal structure represented by Si-NH2. The reason why the method for manufacturing a substrate exhibits the above-mentioned effects is not necessarily clear, but can be presumed to be, for example, as follows.

The coating liquid used in the coating step contains the compound [A] described below, and it is believed that a specific functional group of the compound [A] and a terminal structure represented by Si-NH ₂ form a carbon-nitrogen double bond, thereby selectively forming a film in the region having the terminal structure represented by Si-NH _2. In addition, it is believed that the compound [A] has an aromatic ring structure, which can suppress hydrolysis of the carbon-nitrogen double bond. Furthermore, since the heating step can remove water that causes hydrolysis, it is believed that hydrolysis of the carbon-nitrogen double bond can be further suppressed. With these factors combined, according to the method for manufacturing the substrate, it is believed that a film that exhibits high blocking performance against metal oxide formation by the ALD method or CVD method can be selectively formed by the coating method on a substrate having a region containing a terminal structure represented by Si-NH ₂ on the surface layer.

The method for manufacturing the substrate may include, after the heating step, a step of cleaning the material present in the film formed by the heating step in areas other than the first area with a cleaning solution (hereinafter also referred to as a "cleaning step").

The method for manufacturing the substrate may include a step of depositing a pattern on the surface of the substrate by CVD or ALD after the heating step or the cleaning step (hereinafter also referred to as the "deposition step").

The method for manufacturing the substrate may include a step of peeling off the film formed by the heating step with a peeling solution (hereinafter, also referred to as a "peeling step") after the heating step. The film formed by the method for manufacturing the substrate can be easily peeled off with the peeling solution.

Below, we will explain each step in the manufacturing method for this substrate.

[Coating process]
In this step, a coating liquid is applied to a substrate having a surface layer including a first region including a terminal structure represented by Si- _NH2 . By this step, a coating film is formed on the substrate.

The method for applying the coating liquid is not particularly limited, and examples include spin coating, roll coating, bar coating, etc.

(Base material)
The substrate has a first region on the surface thereof, the first region including a terminal structure represented by Si- _NH2 (hereinafter also referred to as a "primary amino group terminal structure"). The shape of the substrate is not particularly limited, and may be any desired shape, such as a plate (substrate) or a sphere.

The substrate may have a surface region other than the first region (hereinafter also referred to as the "second region"). When the substrate has a surface region of the second region, a blocking film can be selectively formed on the first region.

When the substrate has the second region on the surface, the shape of the first and second regions is not particularly limited, and may be, for example, a planar shape, a dot shape, a stripe shape, etc., in a planar view. The size of the first and second regions is not particularly limited, and may be an appropriate region of a desired size.

Examples of the second region include a region containing nonmetallic atoms and a region containing metal atoms. The second region may be of one type or of two or more types.

Examples of the form in which nonmetallic atoms are contained include simple nonmetallic elements, nonmetallic oxides, nonmetallic nitrides, and nonmetallic oxide nitrides.

Examples of nonmetallic elements include silicon, carbon, and the like. Examples of nonmetallic oxides include silicon oxide, and the like. Examples of nonmetallic oxide nitrides include SiON, and the like. Of these, nonmetallic oxides are preferred, and silicon oxide is more preferred.

There are no particular limitations on the metal atom, so long as it is an atom of a metal element. Silicon is a nonmetallic atom and does not fall under the category of a metal atom. Examples of metal atoms include copper, iron, zinc, cobalt, aluminum, tin, tungsten, zirconium, titanium, tantalum, germanium, molybdenum, ruthenium, gold, silver, platinum, palladium, nickel, and the like. Of these, copper, cobalt, or tungsten is preferred.

Examples of the form in which metal atoms are contained include simple metals, alloys, conductive nitrides, metal oxides, and silicides.

Examples of metal elements include copper, iron, cobalt, tungsten, tantalum, and other metal elements. Examples of alloys include nickel-copper alloys, cobalt-nickel alloys, and gold-silver alloys. Examples of conductive nitrides include tantalum nitride, titanium nitride, iron nitride, and aluminum nitride. Examples of metal oxides include tantalum oxide, aluminum oxide, iron oxide, and copper oxide. Examples of silicides include iron silicide and molybdenum silicide. Among these, metal elements are preferred, and copper, cobalt, or tungsten are more preferred.

In this process, the primary amino group terminal structure in the first region of the substrate surface reacts with a functional group possessed by compound [A], which will be described later, to form a carbon-nitrogen double bond.

An example of the substrate is a substrate containing silicon nitride that has been pretreated to convert the terminal structure represented by Si-H (hereinafter also referred to as "hydrogen terminal structure") on the surface layer into a primary amino group terminal structure. The type of pretreatment is not particularly limited, and examples include wet treatment and dry treatment. Examples of wet treatment include treatment using concentrated acetic acid, dilute hydrofluoric acid, etc. Examples of dry treatment include plasma treatment, etc.

The method for manufacturing the substrate may also include a pretreatment step (hereinafter also referred to as the "pretreatment step") for converting the hydrogen terminal structure in the surface layer of the silicon nitride-containing substrate to a primary amino group terminal structure prior to the coating step.

(Coating Fluid)
The coating liquid used in this step will be described in the section <Coating Liquid> below.

[Heating process]
In this step, the coating film formed in the coating step is heated. This step promotes the reaction between the primary amino group terminal structure and the functional group of the compound [A]. In addition, this step can remove water from the system, thereby suppressing hydrolysis of the carbon-nitrogen double bond formed in the reaction.

The heating means is not particularly limited, and known heating means can be used, such as an oven or a hot plate. The heating temperature and heating time can be appropriately determined taking into consideration various factors such as the presence or absence of a solvent in the coating liquid, the structure of the [A] compound, and the type of functional group possessed by the [A] compound. The lower limit of the heating temperature is preferably 80°C, more preferably 100°C, and even more preferably 130°C. The upper limit of the heating temperature is preferably 400°C, more preferably 300°C, and even more preferably 200°C. The lower limit of the heating time is preferably 10 seconds, more preferably 1 minute, and even more preferably 2 minutes. The upper limit of the heating time is preferably 60 minutes, more preferably 10 minutes, and even more preferably 5 minutes.

The average thickness of the film formed can be adjusted to a desired value by appropriately selecting the type and concentration of the compound [A] in the coating liquid, and the conditions in the heating step, such as the heating temperature and heating time. The lower limit of the average thickness of the film is preferably 0.1 nm, more preferably 1 nm, and even more preferably 3 nm. The upper limit of the average thickness is, for example, 20 nm. The average thickness of the film is a value measured using a spectroscopic ellipsometer (J.A. WOOLLAM's "M2000D").

[Cleaning process]
In this step, the material present in the film formed by the heating step in the regions other than the first region is washed with a cleaning solution. This step is performed after the heating step. This step removes the material that does not form a carbon-nitrogen double bond with the terminal structure in the first region present on the substrate. This step is particularly advantageous when the substrate has a second region, and it is possible to remove the material present on the second region and selectively form a blocking film on the first region.

As the cleaning liquid, an organic solvent is used. For example, the solvents exemplified as solvent [B] described in the <Coating liquid> section below can be used. In addition, when the coating liquid contains solvent [B], the same type of solvent as the solvent [B] contained in the coating liquid can be used as the cleaning liquid.

[Deposition process]
In this process, a pattern is deposited on the surface of the substrate by CVD or ALD. This process is carried out after the heating process or the cleaning process. This process is particularly advantageous when the substrate has a second region, and the film formed on the first region has high blocking performance against metal oxide formation by CVD or ALD, so that a metal oxide pattern can be selectively formed on the second region.

[Peeling process]
In this step, the film formed by the heating step is peeled off with a peeling solution. This step is performed after the heating step or the deposition step. This step is particularly advantageous when the substrate has a second region and is performed after the deposition step, and a metal oxide pattern can be selectively formed on the second region of the substrate by peeling off the film formed by the heating step.

The stripping solution is preferably a solution containing an acid or a solution containing a base. Examples of acids include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid, and carboxylic acids such as acetic acid, citric acid, oxalic acid, maleic acid, isobutyric acid, and 2-ethylhexanoic acid. Of these, carboxylic acids are preferred, and citric acid is more preferred. Examples of bases include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, and tetramethylammonium hydroxide (TMAH). Of these, TMAH is preferred.

Other examples of stripping solutions include ammonium hydroxide-hydrogen peroxide solution (SC-1 cleaning solution) and hydrochloric acid-hydrogen peroxide solution (SC-2 cleaning solution).

The solvent of the stripping solution preferably contains water as a main component. The lower limit of the water content in the solvent is preferably 50% by mass, more preferably 90% by mass, and even more preferably 95% by mass. The above content may be 100% by mass.

<Coating Fluid>
The coating liquid contains a compound (hereinafter also referred to as "compound [A] _") having a functional group and an aromatic ring structure that reacts with a terminal structure (primary amino group terminal structure) represented by Si-NH2 in the first region of the substrate to form a carbon-nitrogen double bond. The coating liquid is liquid at room temperature and normal pressure, and may contain a solvent (hereinafter also referred to as "solvent [B]") as necessary. The coating liquid may contain other components (hereinafter also referred to as "other components") other than compound [A] and solvent [B] within a range that does not impair the effects of the present invention.

The coating liquid is used to be applied to a substrate having a surface layer including a first region containing a primary amino group terminal structure. Specifically, the coating liquid is used in the coating step in the above-mentioned method for manufacturing the substrate.

The components contained in the coating liquid are explained below.

[[A] Compound]
The compound [A] has an aromatic ring structure and a functional group (hereinafter also referred to as “functional group (X)”) that reacts with the primary amino group terminal structure in the first region of the base material to form a carbon-nitrogen double bond.

The [A] compound may be a polymer (hereinafter also referred to as the "[A1] polymer") or a low molecular weight compound (hereinafter also referred to as the "[A2] compound"). In this specification, a "polymer" refers to a compound having repeating units, and a "low molecular weight compound" refers to a compound that is not a polymer, does not have a molecular weight distribution, and has a molecular weight of 1,000 or less.

The functional group (X) is a functional group that reacts with the primary amino group terminal structure to form a carbon-nitrogen double bond. The functional group (X) is preferably an aldehyde group or a ketonic carbonyl group. The compound [A] can have one or more functional groups (X).

Examples of aromatic ring structures include aromatic hydrocarbon ring structures having 6 to 20 ring members and aromatic heterocyclic structures having 5 to 20 ring members. The "number of ring members" refers to the number of atoms that make up the ring structure, and in the case of a polycyclic ring, it refers to the total number of atoms that make up the polycyclic ring.

Examples of aromatic hydrocarbon ring structures having 6 to 20 ring members include a benzene structure, a naphthalene structure, a biphenyl structure, an anthracene structure, a phenanthrene structure, a fluorene structure, a tetracene structure, and a pyrene structure.

Examples of aromatic heterocyclic structures having 5 to 20 ring members include furan structures, benzofuran structures, pyrrole structures, indole structures, thiophene structures, benzothiophene structures, dibenzothiophene structures, imidazole structures, pyrazole structures, and oxazole structures.

The aromatic ring structure is preferably an aromatic hydrocarbon ring structure having 6 to 20 ring members.

The molecular weight of the [A] compound is preferably 200 or more. In the case of the [A1] polymer, "molecular weight" means the weight average molecular weight Mw described below, and in the case of the [A2] compound, it means the sum of the atomic weights of the atoms constituting the low molecular weight compound.

([A1] compound)
When the compound [A] is a polymer [A1], the polymer [A1] has a structural unit containing an aromatic ring structure (hereinafter also referred to as "structural unit (I)") and a functional group (X). The polymer [A1] may have a structural unit other than the structural unit (I).

When the functional group (X) is an aldehyde group, the polymer [A1] preferably has the functional group (X) at the end of the main chain or at the end of the side chain, and more preferably has the functional group (X) at the end of the main chain. The term "main chain" refers to the longest atomic chain among the atomic chains constituting the polymer [A1], and the term "side chain" refers to the atomic chain other than the main chain among the atomic chains constituting the polymer [A1].

The functional group (X) at the end of the main chain can be introduced by treating the polymerization end of a living anionic polymer such as polystyrene with a terminal treatment agent that provides the functional group (X). Examples of terminal treatment agents that provide the functional group (X) include N,N-dimethylformamide.

The [A1] polymer having a functional group (X) at the end of the side chain can be formed by using a monomer having a functional group (X) at the end of the side chain, such as 4-vinylbenzaldehyde, and having an ethylenic carbon-carbon double bond.

When the functional group (X) is a ketonic carbonyl group, the polymer [A1] preferably has the functional group (X) in the main chain. In addition, it is preferable that both ends of the ketonic carbonyl group are bonded to the aromatic ring structure. The ketonic carbonyl group in the main chain can be formed by the Friedel-Crafts reaction, for example, by reacting a compound having an aromatic ring structure such as 2,2'-dimethoxybiphenyl with an aromatic dicarboxylic acid such as 4,4'-dicarboxydiphenyl ether in the presence of trifluoromethanesulfonic acid.

When the [A] compound is an [A1] polymer, the lower limit of the weight average molecular weight Mw of the [A1] polymer is preferably 200, more preferably 1,000, even more preferably 2,000, even more preferably 3,000, and particularly preferably 4,000. The upper limit of the above Mw is preferably 80,000, more preferably 60,000, and in some cases 20,000 or 10,000 is preferred.

[A1] The upper limit of the ratio of Mw to the polystyrene-equivalent number average molecular weight Mn of the polymer as determined by GPC (Mw/Mn, dispersity) is preferably 5, more preferably 2.5, and in some cases 1.5 or 1.3 is preferred. The lower limit of the above ratio is usually 1, and 1.02 is preferred.

[Method of measuring Mw and Mn]
The Mw and Mn of the polymer in this specification are values measured by gel permeation chromatography using GPC columns (two "G2000HXL", one "G3000HXL" and one "G4000HXL" columns) manufactured by Tosoh Corporation under the following conditions.
Eluent: Tetrahydrofuran (FUJIFILM Wako Pure Chemical Industries, Ltd.)
Flow rate: 1.0 mL/min Sample concentration: 1.0 mass%
Sample injection volume: 100 μL
Column temperature: 40°C
Detector: Differential refractometer Standard material: Monodisperse polystyrene

([A2] compound)
When the compound [A] is a compound [A2], the compound [A2] has an aromatic ring structure and a functional group (X). It is preferable that the functional group (X) of the compound [A2] is bonded to the aromatic ring structure. In this case, a blocking film can be more stably formed on a substrate by a coating method.

[A2] Examples of compounds include p-octyloxybenzaldehyde and 3,5-bis(dodecyloxy)benzaldehyde.

When the [A] compound is an [A2] compound, the lower limit of the molecular weight of the [A2] compound is preferably 200, more preferably 300. When the molecular weight of the [A2] compound is equal to or greater than the above lower limit, the coatability of the coating liquid can be further improved. The upper limit of the molecular weight is 1,000, preferably 700, more preferably 600.

[B] Solvent
The solvent [B] is not particularly limited as long as it is a solvent capable of dissolving or dispersing the compound [A] and other components, and examples thereof include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, hydrocarbon-based solvents, etc. The coating liquid may contain one or more types of the solvent [B].

Examples of the alcohol solvent include aliphatic monoalcohol solvents having 1 to 18 carbon atoms, such as 4-methyl-2-pentanol and n-hexanol;
Alicyclic monoalcohol solvents having 3 to 18 carbon atoms, such as cyclohexanol;
Polyhydric alcohol solvents having 2 to 18 carbon atoms, such as 1,2-propylene glycol;
Examples of the solvent include partial ether solvents of polyhydric alcohols having 3 to 19 carbon atoms, such as propylene glycol monomethyl ether.

Examples of the ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, and diheptyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
Examples of the solvent include aromatic ring-containing ether solvents such as diphenyl ether and anisole (methyl phenyl ether).

Examples of the ketone solvent include chain ketone solvents such as acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl isobutyl ketone (MIBK), 2-heptanone (methyl n-pentyl ketone), ethyl n-butyl ketone, methyl n-hexyl ketone, di-isobutyl ketone, and trimethylnonanone;
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, and methylcyclohexanone;
Examples include 2,4-pentanedione, acetonylacetone, and acetophenone.

Examples of the amide solvent include cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone;
Examples of the solvent include chain amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.

Examples of the ester solvent include monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate;
Polyhydric alcohol carboxylate solvents such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate;
Lactone solvents such as γ-butyrolactone and δ-valerolactone;
Polycarboxylic acid diester solvents such as diethyl oxalate;
Examples of the carbonate solvent include dimethyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate.

Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents having 5 to 12 carbon atoms, such as n-pentane and n-hexane;
Examples of the solvent include aromatic hydrocarbon solvents having 6 to 16 carbon atoms, such as toluene and xylene.

Among these, ester-based solvents are preferred, polyhydric alcohol partial ether carboxylate-based solvents, lactone-based solvents or combinations thereof are more preferred, and propylene glycol monomethyl ether acetate, gamma-butyrolactone or combinations thereof are even more preferred.

[Other ingredients]
Examples of the other components include an acid generator, a surfactant, etc. The content of the other components in the coating liquid can be appropriately determined depending on the type of the other components used, etc.

The lower limit of the solid content concentration of the coating liquid is preferably 0.1% by mass, more preferably 0.5% by mass, and even more preferably 0.7% by mass. The upper limit of the solid content concentration is preferably 30% by mass, more preferably 10% by mass, and even more preferably 3% by mass. "Solid content concentration" refers to the concentration (mass %) of all components other than the solvent [B] in the coating liquid.

[Method of preparing coating liquid]
The coating liquid can be prepared, for example, by mixing the compound [A], the solvent [B], and other components as necessary in a predetermined ratio, and filtering the mixture through a high-density polyethylene filter having pores of preferably 0.45 μm or less.

The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. The measurement methods for each physical property value are shown below.

[Weight average molecular weight (Mw), number average molecular weight (Mn) and dispersity (Mw/Mn)]
The Mw and Mn of the polymer were measured according to the conditions described in the above section [Method of measuring Mw and Mn]. The dispersity (Mw/Mn) of the polymer was calculated from the measurement results of Mw and Mn.

[ ¹³ C-NMR analysis]
The ¹³ C-NMR analysis was carried out using a nuclear magnetic resonance apparatus ("JNM-EX400" manufactured by JEOL Ltd.) and CDCl ₃ as a measurement solvent. The content ratio of each structural unit in the polymer was calculated from the area ratio of the peak corresponding to each structural unit in the spectrum obtained by ¹³ C-NMR.

<Synthesis of compound [A]>
Among the compounds [A], polymers (A1-1) to (A1-3) were synthesized as the polymer [A1], and the following compound (A2-1) was synthesized as the compound [A2]. In addition, polymers (a1-1) to (a1-3) were synthesized as controls for the polymer [A1].

Synthesis Example 1 Synthesis of Polymer (A1-1) (BZP-co-BP(OMe)2) 7.8 g of 4,4'-dicarboxydiphenyl ether, 7.7 g of 2,2'-dimethoxybiphenyl, and 45 mL of trifluoromethanesulfonic acid were added to a three-neck flask equipped with a thermometer and a stirrer bar, and the mixture was heated and stirred at 40°C for 24 hours under a nitrogen atmosphere. After the reaction was completed, 45 mL of water was slowly added dropwise to precipitate a polymer, which was then recovered in a Buchner funnel and dried under reduced pressure. This polymer was dissolved in a small amount of N,N-dimethylacetamide, precipitated and purified in 2-propanol, recovered in a Buchner funnel, and dried under reduced pressure to obtain 12.8 g of a polymer represented by the following formula (A1-1) (hereinafter also referred to as "polymer (A1-1)" or "BZP-co-BP(OMe)2"). The polymer (A1-1) had an Mw of 50,000, an Mn of 24,800, and an Mw/Mn of 2.02.

[Synthesis Example 2] Synthesis of polymer (A1-2) (PS-r-PStCHO) 10 g of methyl ethyl ketone was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and kept at 80 ° C., and a mixture of 7.28 g of styrene, 3.96 g of 4-vinylbenzaldehyde, 0.69 g of dimethyl-2,2'-azobis(2-methylpropionate), and 20 g of methyl ethyl ketone was dropped from a feeder for 3 hours. After the dropwise addition was completed, the mixture was aged at 80 ° C. for 3 hours. The obtained polymerization solution was purified by precipitation with a 5-fold amount of methanol to obtain 7.31 g of a white solid polymer represented by the following formula (A1-2) (hereinafter, also referred to as "polymer (A1-2)" or "PS-r-PStCHO"). The Mw of the polymer (A-2) was 5,780, the Mn was 3,140, and the Mw/Mn was 1.84. As a result of ¹³ C-NMR analysis, the molar ratio of structural units derived from styrene to structural units derived from 4-vinylbenzaldehyde in polymer (A1-2) was 58:42.

[Synthesis Example 3] Synthesis of polymer (A1-3) (PS-w-CHO) After drying a 500 mL flask reaction vessel under reduced pressure, 120 g of tetrahydrofuran (THF) that had been subjected to distillation and dehydration treatment under a nitrogen atmosphere was poured in and cooled to -78 ° C. Next, 2.38 mL of a 1N cyclohexane solution of sec-butyl lithium (sec-BuLi) was poured into this THF, and then 13.3 mL of styrene that had been subjected to adsorption filtration with silica gel and distillation and dehydration treatment to remove the polymerization inhibitor was dripped in over 30 minutes, and it was confirmed that the polymerization system was orange. During this dripping, care was taken to ensure that the internal temperature of the reaction solution did not exceed -60 ° C. After the dripping was completed, the mixture was aged for 30 minutes. Then, 0.18 ml of N,N-dimethylformamide was poured in to carry out a termination reaction of the polymerization terminals. The reaction solution was heated to room temperature, and the resulting reaction solution was concentrated and replaced with methyl isobutyl ketone (MIBK). Into the obtained solution, 1,000 g of a 2% aqueous solution of oxalic acid was poured and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove metal salts. Then, 1,000 g of ultrapure water was poured and stirred to remove the lower aqueous layer. This operation was repeated three times to remove oxalic acid, and the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and the solid was collected using a Buchner funnel. This solid was dried under reduced pressure at 60° C. to obtain 11.9 g of a white polymer represented by the following formula (A-3) (hereinafter also referred to as "polymer (A1-3)" or "PS-w-CHO"). The polymer (A1-3) had an Mw of 5,000, an Mn of 4,800, and an Mw/Mn of 1.04.

Synthesis Example 4 Synthesis of Compound (A2-1) (3,5-bis(dodecyloxy)benzaldehyde) 8.37 g of 3,5-dihydroxybenzaldehyde, 44.5 g of 1-bromododecane, 300 g of N,N-dimethylformamide, and 20.7 g of potassium carbonate were added to a 1 L eggplant flask, and the mixture was heated and stirred at 80° C. for 16 hours under a nitrogen atmosphere. After cooling, potassium carbonate and salts were removed using a Kiriyama Funnel (registered trademark), and the mixture was washed four times with toluene/ultrapure water. The organic layer was collected, water was removed using anhydrous sodium sulfate, and the filtrate was collected using pleated filter paper and concentrated under reduced pressure. Next, purification was performed by column chromatography using hexane/methylene chloride=10/1 to obtain 32 g of white solid 3,5-bis(dodecyloxy)benzaldehyde (hereinafter also referred to as "compound (A2-1)"). The molecular weight of compound (A2-1) was 474.

Synthesis Example 5: Synthesis of polymer (a1-1) (PS-w-(CN)2) 10.0 g of polymer (A1-3) obtained in Synthesis Example 3 was dissolved in 40 g of toluene, and 0.21 g of malononitrile, 0.25 g of ammonium acetate, and 0.038 g of acetic acid were added, followed by heating and dry distillation at 115° C. for 4 hours under a nitrogen atmosphere. The reaction solution was heated to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. 500 g of a 2% aqueous solution of sodium bicarbonate was poured into the resulting solution, stirred, and allowed to stand, after which the lower aqueous layer was removed. This operation was repeated three times. Then, 1,000 g of ultrapure water was poured and stirred to remove the lower aqueous layer. After repeating this operation three times, the solution was concentrated and dropped into 500 g of methanol to precipitate the polymer, and the solid was collected using a Buchner funnel. This solid was dried under reduced pressure at 60° C. to obtain 9.8 g of a white polymer represented by the following formula (a1-1) (hereinafter also referred to as "polymer (a1-1)" or "PS-w-(CN)2"). Polymer (a1-1) had Mw of 5,300, Mn of 5,100, and Mw/Mn of 1.04.

[Synthesis Example 6] Synthesis of polymer (a1-2) (PS-w-PO3Et2) After drying a 500 mL flask reaction vessel under reduced pressure, 120 g of THF that had been subjected to distillation and dehydration treatment under a nitrogen atmosphere was poured in and cooled to -78 ° C. Then, 2.30 mL of a 1N cyclohexane solution of sec-BuLi was poured into this THF, and then 13.3 mL of styrene that had been subjected to adsorption filtration with silica gel and distillation and dehydration treatment to remove the polymerization inhibitor was dripped in over 30 minutes while taking care not to allow the internal temperature of the reaction solution to exceed -60 ° C., and then stirred for 30 minutes. After this, 0.33 ml of diethyl chlorophosphate was poured in to carry out a termination reaction of the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Then, 200 g of a 2% by mass aqueous solution of oxalic acid was poured in and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the lithium salt. Thereafter, 200 g of ultrapure water was poured in and stirred, and the lower aqueous layer was removed. This operation was repeated four times to remove the oxalic acid, and then the solution was concentrated and dropped into 400 g of methanol to precipitate a polymer, and the solid was collected using a Buchner funnel. This solid was dried under reduced pressure at 60°C to obtain 11.5 g of a white polymer represented by the following formula (a1-2) (hereinafter also referred to as "polymer (a1-2)" or "PS-w-PO3Et2"). Polymer (a1-2) had an Mw of 5,100, an Mn of 4,900, and an Mw/Mn of 1.04.

[Synthesis Example 7] Synthesis of polymer (a1-3) (PS-w-PO3H2) 0.81 g of triethylamine, 4 g of propylene glycol monomethyl ether, and 40 g of propylene glycol monomethyl ether acetate were added to 10.0 g of polymer (a1-2) obtained in Synthesis Example 6, and the mixture was heated and stirred at 80°C for 6 hours under a nitrogen atmosphere. The reaction solution was heated to room temperature, and the reaction solution was concentrated and replaced with MIBK. Then, 200 g of ultrapure water was poured and stirred, and the lower aqueous layer was removed. This operation was repeated three times to remove triethylamine, and then the solution was concentrated and dropped into 400 g of methanol to precipitate a polymer, and the solid was collected using a Buchner funnel. The solid was dried under reduced pressure at 60°C to obtain 9.2 g of a white polymer represented by the following formula (a1-3) (hereinafter also referred to as "polymer (a1-3)" or "PS-w-PO3H2"). The polymer (a1-3) had an Mw of 5,100, an Mn of 4,800, and an Mw/Mn of 1.06.

<Preparation of Coating Fluid>
The solvents [B] used in preparing the coating liquid are shown below.
Solvent (B-1): Propylene glycol monomethyl ether acetate (PGMEA)
Solvent (B-2): γ-butyrolactone

[Example 1-1] Preparation of Coating Liquid (S-1) 79 g of Solvent (B-1) and 19.8 g of Solvent (B-2) were added to 1.30 g of Polymer (A-1) as Compound (A), and the mixture was stirred and then filtered through a high-density polyethylene filter having pores of 0.45 μm to prepare Coating Liquid (S-1). The solid content of Coating Liquid (S-1) was 1.2%.

[Examples 1-2 to 1-4 and Comparative Examples 1-1 to 1-3] Preparation of Coating Liquids (S-2) to (S-4) and (CS-1) to (CS-3) Coating liquids (S-2) to (S-4) and (CS-1) to (CS-3) were prepared in the same manner as in Example 1-1 above, except that the components were used in the types and amounts shown in Table 1 below. The solids concentrations of coating liquids (S-2) to (S-4) and (CS-1) to (CS-3) are also shown in Table 1 below.

<Membrane formation>
[substrate]
The substrates used were as follows:
th- _SiO2 : 8-inch silicon dioxide substrate with thermal oxide film SiN: 8-inch silicon nitride substrate Cu: 8-inch copper substrate Co: 8-inch cobalt substrate W: 8-inch tungsten substrate The above substrates were subjected to plasma treatment with a _N2 /(3%) _H2 mixed gas ([conditions] 25°C, chamber pressure: 30 Pa, treatment time: 5 minutes, flow rate: 300 sccm, microwave: 300 mW) using a plasma treatment device (ULVAC, Inc.'s "Luminous NA-1300"). This plasma treatment converts the Si-H terminal structures present on the surface layer of the SiN substrate into Si- _NH2 terminal structures.

[Example 2-1]
Various substrates shown in Table 2 below were cut to 3 cm x 3 cm, and the composition (S-1) prepared above was spin-coated at 1,500 rpm for 20 seconds using a spin coater (MS-B300 from Mikasa Co., Ltd.) to form a coating film (coating step). Next, the substrate on which the coating film was formed was baked at 150°C for 180 seconds to form a film (heating step). Thereafter, the substrate was washed with propylene glycol monomethyl ether acetate (washing step). In the washing step, if no film is adsorbed on the substrate surface, the unadsorbed film is removed.

The static contact angles of the surfaces of the substrates that had undergone the above series of processes including the coating process, heating process, and cleaning process were measured using a contact angle meter (Drop Master DM-501, manufactured by Kyowa Interface Science Co., Ltd.). The static contact angles were 38° for the th- _SiO2 substrate, 85° for the SiN substrate, 36° for the Cu substrate, 40° for the Co substrate, and 42° for the W substrate. The static contact angle values of the various substrates before the above process were 36° for the th- _SiO2 substrate, 25° for the SiN substrate, 36° for the Cu substrate, 42° for the Co substrate, and 45° for the W substrate, indicating that a film was selectively formed on the SiN substrate, which had a significantly increased static contact angle compared to the static contact angle before the above process.

[Examples 2-2 to 2-4 and Comparative Examples 2-1 to 2-3]
The static contact angle was measured in the same manner as in Example 2-1, except that the coating liquid shown in Table 2 was used. The results are shown in Table 2.

In Table 2 below, the numbers in parentheses next to the names of various substrates indicate the static contact angle (Blank SCA) of each substrate before processing.

<Wet peelability evaluation of film>
[Example 3-1]
The various substrates subjected to a series of treatments in Example 2-1 were immersed in a petri dish in which a 2% by mass citric acid aqueous solution was poured for 3 minutes, and further immersed in a petri dish in which a 2.38% by mass tetramethylammonium hydroxide aqueous solution was poured for 3 minutes. Then, after washing with propylene glycol monomethyl ether acetate, the static contact angles of the substrate surfaces were measured using the contact angle meter, and the values were 38° for the th-SiO ₂ substrate, 24° for the SiN substrate, 32° for the Cu substrate, 38° for the Co substrate, and 42° for the W substrate. The static contact angle values of the various substrates before the wet peeling treatment (Example 2-1) were 38° for the th-SiO ₂ substrate, 85° for the SiN substrate, 34° for the Cu substrate, 40° for the Co substrate, and 42° for the W substrate, which shows that the film formed on the SiN substrate was wet peeled off.

[Examples 3-2 to 3-4 and Comparative Examples 3-1 to 3-3]
The static contact angles were measured by carrying out the same treatment as in Example 3-1, except that the various substrates that had been subjected to the series of treatments in Examples 2-2 to 2-4 and Comparative Examples 2-1 to 2-3 were used. The results are shown in Table 3 below.

In Table 3 below, the values in parentheses next to the names of various substrates indicate the static contact angles (Blank SCA) of the various substrates before the treatment in the <Film formation> section above. In Table 3 below, the values "before peeling" are all the values in Table 2 above.

<Metal oxide blocking evaluation>
[Example 4-1]
In order to evaluate the state of film formation on the surface of the SiN substrate that had been subjected to the series of processes in Example 2-1, a metal oxide blocking evaluation was performed to measure the degree of inhibition of oxide layer formation by ALD. As a control, the SiN substrate before the series of processes in Example 2-1 was used.

[Oxide layer formation by ALD]
ALD was performed using Cambridge Nanotech FIJI at Stanford University under the conditions shown in Table 4. Trimethylaluminum was used as the precursor and water was used as the co-catalyst. The ALD cycle was fixed at 47 cycles.

[ESCA analysis]
The Al component on the SiN substrate surface after the ALD was quantified by ESCA analysis. The ESCA analysis was performed using ULVAC's "Quantum 2000" to quantify the Al component excluding the film component and the substrate component under the condition of 100 μmφ at Al2p (72-78 eV). Thereafter, the quantitative value of the Al component measured on the SiN substrate before the series of processes in Example 2-1 was used as a reference, and the degree to which the quantitative value decreased from the reference quantitative value was calculated as a blocking rate (%). As a result, the blocking rate of the SiN substrate when the coating liquid S-1 was used was 98.6%. Since a larger value of the blocking rate means a film with higher metal oxide blocking performance, it can be seen that the film formed on the SiN substrate has high blocking performance against metal oxide formation by the ALD method.

[Examples 4-2 to 4-4 and Comparative Examples 4-1 to 4-3]
The same treatment as in Example 4-1 was carried out, except that the SiN substrates that had been subjected to a series of treatments in Examples 2-2 to 2-4 and Comparative Examples 2-1 to 2-3 were used, and the blocking ratio was calculated. The results are shown in Table 5 below. All of the Examples had excellent blocking performance, whereas the Comparative Examples had almost no blocking performance.

Claims (9)

A step of applying a coating liquid to a substrate having a first region on a surface layer thereof, the first region including a terminal structure represented by Si- _NH2;
and a step of heating the coating film formed by the coating step.
The method for producing a substrate, wherein the coating liquid contains a compound having an aromatic ring structure and a functional group that reacts with the terminal structure of the first region to form a carbon-nitrogen double bond. The method for manufacturing a substrate according to claim 1, wherein the molecular weight of the compound is 200 or more. The method for manufacturing a substrate according to claim 1 or 2, wherein the compound is a polymer having a structural unit containing an aromatic ring structure. The method for manufacturing a substrate according to claim 3, wherein the polymer has the functional group at the end of the main chain or at the end of the side chain. The method for manufacturing a substrate according to any one of claims 1 to 4, wherein the functional group is an aldehyde group or a ketonic carbonyl group. The method for manufacturing a substrate according to any one of claims 1 to 5, wherein the aromatic ring structure is an aromatic hydrocarbon ring structure. The method for manufacturing a substrate according to any one of claims 1 to 6, wherein the substrate further has a second region containing silicon oxide on the surface layer. The method for manufacturing a substrate according to any one of claims 1 to 7, wherein the coating liquid further contains a solvent. A film-forming coating solution used to be applied to a substrate having a surface layer including a first region including an end structure represented by Si- _NH2 ,
The film-forming coating liquid contains a compound having an aromatic ring structure and a functional group that reacts with the terminal structure of the first region to form a carbon-nitrogen double bond.