Rinse solution, substrate processing method, and semiconductor device manufacturing method

Abstract

To provide a rinse solution that is highly effective in suppressing pattern collapse, and a substrate processing method using the rinse solution, and a method for manufacturing semiconductor elements.SOLUTION: A rinse solution for rinsing a substrate having convex portions, contains an organic solvent (S1) having neither hydroxyl group nor fluorine atom and having a dynamic viscosity of 1.05×106 m2 / s or less. A method for processing a substrate includes a process (A) of contacting the rinse solution according to any one of claims 1 to 5 with a surface having convex portions of the substrate having convex portions, and removing the rinse solution from the surface having convex portions (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a rinse liquid, a substrate processing method, and a semiconductor device manufacturing method. [Background technology]

[0002] In recent years, advances in lithography technology have led to rapid advances in the miniaturization of semiconductor substrate patterns in the manufacture of semiconductor elements and liquid crystal display elements. As semiconductor substrate patterns become finer, the aspect ratios of the patterns tend to increase.

[0003] Meanwhile, in semiconductor manufacturing processes, contamination by residues and particles after dry etching can reduce manufacturing yields. Therefore, chemical treatment of substrates using cleaning liquids is performed to remove residues and particles remaining on the substrate. After the chemical treatment, a rinse process using pure water or other liquids is performed, in which pure water is supplied to the substrate to remove the chemicals, and a drying process is performed in which the substrate is rotated at high speed to remove the liquid on the substrate. The rinse liquid used in the rinse process is not limited to pure water; other solvents may also be used. By performing the rinse and drying processes in sequence, the rinse liquid (not limited to pure water) is removed by drying the substrate. However, when a fine pattern is formed on a substrate, the pattern on the substrate surface may collapse during drying due to the capillary force of the rinse liquid remaining in the pattern. Specific methods for suppressing pattern collapse include a method (IPA method) in which 2-propanol (IPA) is supplied to a substrate after a rinse process with pure water following a chemical treatment, and the IPA, which has a lower surface tension than water, is then spun off and dried (IPA method); and a method (hot IPA method) in which IPA is supplied to a heated substrate after a rinse process with pure water, or heated IPA is supplied to a substrate, and the rinse liquid on the substrate is replaced with IPA (see Patent Document 1). An example of the hot IPA method is the following procedure: After the rinse process, IPA is supplied to the upper surface of the substrate to replace the rinse liquid, forming an IPA liquid film on the substrate. Next, the substrate is heated to form an IPA vapor film between the IPA liquid film and the upper surface of the substrate, causing the IPA liquid film to float from the upper surface of the substrate, and then the liquid film is removed from the substrate. When removing the IPA liquid film from the substrate, nitrogen gas is sprayed onto the center of the liquid film to partially remove the liquid film, forming a small-diameter dry area. By blowing nitrogen gas further onto the center of the substrate while rotating it, the dried region is expanded and spread over the entire upper surface of the substrate, thereby drying the upper surface of the substrate while suppressing pattern collapse. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 039784 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when cleaning a substrate having a pattern with a high aspect ratio, the conventional IPA method and the hot IPA method may not be able to sufficiently prevent the pattern from collapsing.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rinse liquid that is highly effective in suppressing pattern collapse, a substrate processing method using the rinse liquid, and a semiconductor device manufacturing method. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention employs the following configuration.

[0008] The first aspect of the present invention is a hydroxyl- and fluorine-free acrylic resin having a dynamic viscosity of 1.05 × 10 6 m 2 The rinse solution for rinsing a substrate having a convex portion contains an organic solvent (S1) having a viscosity of 1 / s or less.

[0009] A second aspect of the present invention is a rinse liquid for rinsing a substrate having a protrusion, which contains a compound represented by the following general formula (S1-1).

[0010] [ka] [In the formula, R 1 represents a linear or branched saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms; and n1 represents 2 or 3.

[0011] A third aspect of the present invention is a method for treating a substrate having convex portions, the method comprising: a step (A) of contacting a surface having convex portions of a substrate having convex portions with a rinse solution according to the first or second aspect; and a step (B) of removing the rinse solution from the surface having convex portions.

[0012] A fourth aspect of the present invention is a method for manufacturing a semiconductor device, comprising the step of treating a substrate having a protrusion by the substrate treating method according to the third aspect. [Effects of the Invention]

[0013] According to the present invention, there are provided a rinse liquid that is highly effective in suppressing pattern collapse, a substrate processing method using the rinse liquid, and a semiconductor device manufacturing method. [Brief explanation of the drawings]

[0014] [Figure 1]FIG. 1 is a flow chart showing an example of a substrate processing method. [Figure 2] FIG. 1 is a flow chart showing an example of a substrate processing method. [Figure 3] FIG. 1 is a flow chart showing an example of a substrate processing method. [Figure 4] FIG. 1 is a flow diagram showing an example of supercritical drying. [Figure 5] An example of a concave-convex pattern is shown. DETAILED DESCRIPTION OF THE INVENTION

[0015] (rinse) The rinse solution according to the first aspect of the present invention is a rinse solution having no hydroxyl group or fluorine atom and a dynamic viscosity of 1.05×10 6 m 2 / s or less organic solvent (S1). The rinse solution according to the second aspect of the present invention contains a compound represented by the general formula (S1-1) described below. The compound represented by the general formula (S1-1) generally falls under the category of organic solvent (S1), but may also include compounds that do not fall under the category of organic solvent (S1). The rinse liquid according to the above embodiment is used to rinse a substrate having a convex portion.

[0016] <Organic solvent (S1)> The organic solvent (S1) is an organic solvent having no hydroxyl group or fluorine atom and having a dynamic viscosity of 1.05 × 10 6 m 2 It is an organic solvent with a viscosity of less than / s. As will be shown in the examples below, we searched for a rinse solution that is more effective at destroying patterns than IPA, and found one with a dynamic viscosity of 1.05 × 10 6 m 2 It was found that pattern collapse was suppressed more effectively by using an organic solvent with a dynamic viscosity of 1.05 × 10 / s or less than IPA. 6 m 2 At a rate of 1 / s or less, the rinse solution spreads evenly over the substrate, which may contribute to suppressing pattern collapse. The lower limit of the dynamic viscosity of the organic solvent (S1) is not particularly limited, but may be, for example, 1.0×10 4 m 2 The dynamic viscosity of the organic solvent (S1) is, for example, 1.0 × 10 4 m 2 / s or more, 5.0×10 4 m 2 / s or more, 1.0×10 5 m 2 / s or more, 5.0×10 5 m 2 / s or more, 6.0×10 5 m 2 / s or more, 7.0×10 5 m 2 / s or more, 6.0×10 5 m 2 / s or more, or 9.0 x 10 5 m 2 / s or more.

[0017] The dynamic viscosity of the organic solvent can be calculated by the following formula (1). Dynamic viscosity (m 2 / s)=viscosity (cp) / density (g / ml) ···(1)

[0018] The viscosity is measured at 25°C. The viscosity may be a measured value or a theoretical value. When a measured value is used, the viscosity at 25°C may be measured using a viscometer. When a theoretical value is used, the viscosity may be an estimated value calculated using software such as HSPiP. The density is the density at 25°C. The density may be an actually measured value or a theoretical value. When an actually measured value is used, the density at 25°C may be measured with a density meter. When a theoretical value is used, an estimated value calculated using software such as HSPiP may be used.

[0019] The organic solvent (S1) is characterized by having no hydroxyl groups or fluorine atoms. The absence of hydroxyl groups prevents intermolecular hydrogen bonds from becoming too strong, and the surface tension tends to be low. In addition, organic solvents containing fluorine have high ozone depletion potential and global warming potential, and therefore pose a heavy burden on the environment. Because the organic solvent (S1) does not have fluorine atoms, it can have a low burden on the environment.

[0020] The organic solvent (S1) may have a latent heat of vaporization at its boiling point of 40 KJ / mol or less. The latent heat of vaporization at its boiling point is preferably 20 to 40 KJ / mol, more preferably 25 to 40 KJ / mol. The latent heat of vaporization at its boiling point can be calculated by the Joback method. The organic solvent (S1) may have a latent heat of vaporization of 43 KJ / mol or less at 25° C. The latent heat of vaporization at 25° C. is preferably from 20 to 43 KJ / mol, more preferably from 25 to 43 KJ / mol. The organic solvent (S1) may have a latent heat of vaporization of 45 KJ / mol or less at 60° C. The latent heat of vaporization at 25° C. is preferably from 20 to 45 KJ / mol, more preferably from 25 to 45 KJ / mol. The latent heat of vaporization at 25°C and 60°C can be calculated using Watson's equation. When the latent heat of vaporization of the organic solvent (S1) is equal to or less than the above-mentioned preferable upper limit, moisture in the air is less likely to condense when the organic solvent (S1) volatilizes, and therefore defects caused by water marks are less likely to remain on the substrate, resulting in a reduction in defects on the substrate after rinsing and drying.

[0021] The organic solvent (S1) may have a Hansen solubility parameter close to that of carbon dioxide (CO2). When the Hansen solubility parameter of the organic solvent (S1) is close to that of carbon dioxide, the compatibility of the organic solvent (S1) with carbon dioxide is high. When the compatibility with CO2 is high, the organic solvent (S1) is easily replaced by supercritical CO2 when supercritical drying is performed using supercritical CO2.

[0022] The Hansen solubility parameters can be calculated from predetermined parameters based on the solubility parameters and cohesion characteristics explained by Charles M. Hansen in, for example, "Hansen Solubility Parameters: A User's Handbook" by Charles M. Hansen, CRC Press (2007) and "The CRC Handbook and Solubility Parameters and Cohesion Parameters," edited by Allan F. M. Barton (1999). Software such as HSPiP can be used to calculate the Hansen solubility parameters.

[0023] Hansen solubility parameters are theoretically calculated as numerical constants and are useful tools for predicting the ability of a solvent material to dissolve a particular solute. The Hansen Solubility Parameters can be used as a measure of the overall strength and selectivity of a material by combining the following three experimentally and theoretically derived Hansen Solubility Parameters (i.e., δD, δP, and δH). The Hansen Solubility Parameters are expressed in units of MPa. 0.5 or (J / cc) 0.5 It is granted at. δD: Energy derived from intermolecular dispersion forces. δP: Energy resulting from intermolecular polar forces. δH: Energy derived from intermolecular hydrogen bonding forces.

[0024] The compatibility between the organic solvent (S1) and carbon dioxide may be indicated by the interaction distance (Ra) between the Hansen solubility parameters. The Hansen solubility parameters (δD, δP, δH) are plotted as coordinates for points in three dimensions, also known as Hansen space. In this three-dimensional space (Hansen space), the closer two molecules are to each other, the higher the possibility that they will dissolve in each other. To evaluate whether two molecules (molecules (1) and (2)) are close to each other in Hansen space, the interaction distance (Ra) between the Hansen solubility parameters is calculated. Ra is calculated using the following formula:

[0025] (Ra) 2 =4(δ d2 -δ d1 ) 2 +(δ p2 -δ p1 ) 2 +(δ h2 -δ h1 ) 2 [In the above formula, δ d1 , δ p1 , and δ h1 denote δD, δP, and δH of molecule (1), respectively. δ d2 , δ p2 , and δ h2 represent δD, δP, and δH of molecule (2), respectively.

[0026] The ΔD of the organic solvent (S1) is, for example, 13 to 17, and 14 to 16 is preferred. The ΔP of the organic solvent (S1) is, for example, 3 to 8, and 4 to 7 is preferred. The ΔH of the organic solvent (S1) is, for example, 2 to 8, and 3 to 7 is preferred.

[0027] The organic solvent (S1) is preferably an ether-based solvent. Specific examples of the organic solvent (S1) include compounds represented by the following general formula (S1-1). The rinse solution according to this embodiment contains a compound represented by the following general formula (S1-1), which provides excellent pattern collapse suppression. Furthermore, the rinse solution contains a compound represented by the following formula (S1-1), which can reduce watermark defects. The compound represented by the following formula (S1-1) has high compatibility with CO2 and can be suitably used as an organic solvent for a supercritical drying process.

[0028] [ka] [In the formula, R 1 represents a linear or branched saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms; and n1 represents 2 or 3.

[0029] The organic solvent (S1) must be able to replace the water rinse when rinsed with water after chemical treatment. In this case, solubility in water is required. Therefore, R 1 has 1 to 3 carbon atoms.

[0030] The compound represented by the general formula (S1-1) preferably contains at least one organic solvent selected from the group consisting of dimethoxyethane, dimethoxypropane, and trimethoxypropane. Specific examples of the compound represented by general formula (S1-1) include 1,2-dimethoxyethane (a compound represented by formula (S1-1-1) below), 2,2-dimethoxypropane (a compound represented by formula (S1-1-2) below), 1,1,1-trimethoxypropane (a compound represented by formula (S1-1-3) below), 1,2,3-trimethoxypropane (a compound represented by formula (S1-1-4) below), and 1,1,3-trimethoxypropane (a compound represented by formula (S1-1-5) below).

[0031] [ka]

[0032] The organic solvent (S1) or the compound represented by the formula (S1-1) (hereinafter collectively referred to as "component (S1)") may be used alone or in combination of two or more kinds. The content of the component (S1) in the rinse solution of this embodiment is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and particularly preferably 70% by mass or more, based on the total mass of the rinse solution. The content of the component (S1) in the rinse solution of this embodiment may be 100% by mass, based on the total mass of the rinse solution. The content of the component (S1) in the rinse solution of this embodiment may be 30 to 100% by mass, 50 to 100% by mass, 60 to 100% by mass, 70 to 100% by mass, or 80 to 100% by mass, based on the total mass of the rinse solution. When the content of the component (S1) is within the above preferred range, the effect of suppressing pattern collapse is further improved.

[0033] <Optional ingredients> The rinse solution of this embodiment may contain optional components in addition to the component (S1), such as an organic solvent other than the organic solvent (S1) (hereinafter also referred to as "organic solvent (S2)").

[0034] As the organic solvent (S2), for example, a solvent having a dynamic viscosity of 1.05 × 10 6 m 2 Examples include organic solvents with a dynamic viscosity of more than 1.05 × 10 / s, organic solvents containing hydroxyl groups, and organic solvents containing fluorine atoms. 6 m 2 Examples of organic solvents having a viscosity of more than / s include protic polar solvents such as glycol solvents, glycol ether solvents, and alcohol solvents; aprotic polar solvents such as ester solvents, amide solvents, sulfoxide solvents, and nitrile solvents; and hydrocarbon solvents. Examples of organic solvents containing a hydroxyl group include protic polar solvents such as glycol solvents, glycol ether solvents, and alcohol solvents. Examples of organic solvents containing a fluorine atom include organic solvents in which one or more hydrogen atoms of the organic solvents listed above have been substituted with fluorine atoms. Examples of the organic solvent (S2) include alcohol-based solvents, and specific examples of the alcohol-based solvent include 2-propanol.

[0035] The organic solvent (S2) may be used alone or in combination of two or more kinds. The content of the organic solvent (S2) in the rinse solution of this embodiment is preferably 70% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, and particularly preferably 30% by mass or less, relative to the total mass of the rinse solution. The content of the organic solvent (S2) in the rinse solution of this embodiment may be 0 to 70% by mass, 0 to 60% by mass, 0 to 50% by mass, 0 to 40% by mass, 0 to 30% by mass, 0 to 20% by mass, or 0 to 10% by mass, relative to the total mass of the rinse solution. The ratio (mass ratio) of the component (S1) to the organic solvent (S2) may be [component (S1) / organic solvent (S2)]=20 / 80 to 100 / 0, 30 / 70 to 100 / 0, 40 / 60 to 100 / 0, 50 / 50 to 100 / 0, 60 / 40 to 100 / 0, 70 / 30 to 100 / 0, 80 / 20 to 100 / 0, or 90 / 10 to 100 / 0. When the content of the organic solvent (S2) is within the above-mentioned preferred range, the effect of suppressing pattern collapse is further improved. When the ratio (mass ratio) of the (S1) component to the organic solvent (S2) is within the above-mentioned preferred range, the effect of suppressing pattern collapse is further improved.

[0036] Examples of optional components other than the organic solvent (S2) include metal chelating agents (aminocarboxylic acid chelating agents, phosphonic acid chelating agents, acetylene alcohol, etc.), pH adjusters, surfactants, etc.

[0037] The rinse solution of this embodiment does not need to contain the organic solvent (S2). 6 m 2 / s. The rinse solution of this embodiment may not contain one or more selected from the group consisting of glycol-based solvents, glycol ether-based solvents, and alcohol-based solvents. The rinse solution of this embodiment may not contain a protic polar solvent. The rinse solution of this embodiment may not contain one or more selected from the group consisting of ester-based solvents, amide-based solvents, sulfoxide-based solvents, and nitrile-based solvents. The rinse solution of this embodiment may not contain an aprotic polar solvent. The rinse solution of this embodiment may not contain a fluorine-containing organic solvent. The rinse solution of this embodiment may not contain a hydrocarbon-based solvent. The rinse solution of this embodiment may not contain 2-propanol. The rinse solution of this embodiment may not contain any organic solvent other than the compound represented by general formula (S1-1). The rinse solution of this embodiment may not contain a surfactant. The rinse solution of this embodiment may not contain a metal chelating agent. The rinse liquid of this embodiment may not contain a pH adjuster, may not contain water, or may not contain a water repellent.

[0038] <Impurities, etc.> The rinse solution of this embodiment may contain metal impurities, including metal atoms such as Fe atoms, Cr atoms, Ni atoms, Zn atoms, Ca atoms, or Pb atoms. The total content of the metal atoms in the rinse solution of this embodiment is preferably 100 mass ppt or less, based on the total mass of the rinse solution. The lower limit of the total metal atom content is preferably as low as possible, and may be, for example, 0.001 mass ppt or more. The total metal atom content may be, for example, 0.001 mass ppt to 100 mass ppt. By setting the total metal atom content to the preferred upper limit or less, the rinse solution is able to improve its ability to suppress defects and residues. By setting the total metal atom content to the preferred lower limit or more, it is believed that metal atoms are less likely to be isolated and present in the system, which is less likely to adversely affect the overall production yield of the rinsed object. The content of metal impurities can be adjusted by, for example, a purification treatment such as filtering, etc. The purification treatment such as filtering may be performed on a part or all of the raw materials before preparing the rinse liquid, or may be performed after preparing the rinse liquid.

[0039] The rinse solution of this embodiment may contain, for example, impurities derived from organic substances (organic impurities). The total content of the organic impurities in the rinse solution of this embodiment is preferably 5000 mass ppm or less. The lower limit of the organic impurity content is preferably as low as possible, and may be, for example, 0.1 mass ppm or more. The total content of the organic impurities may be, for example, 0.1 mass ppm to 5000 mass ppm.

[0040] The rinse solution of this embodiment may contain countable particles of a size that can be counted by a light scattering liquid particle counter. The size of the countable particles is, for example, 0.04 μm or more. The number of countable particles in the rinse solution of this embodiment is, for example, 1,000 or less per mL of rinse solution, with the lower limit being, for example, 1 or more.

[0041] The organic impurities and / or the entities to be counted may be added to the rinse liquid, or may be inevitably mixed into the rinse liquid during the manufacturing process of the rinse liquid. Examples of inevitable mixing during the manufacturing process of the rinse liquid include, but are not limited to, cases where organic impurities are contained in raw materials (e.g., organic solvents) used to manufacture the rinse liquid, and cases where organic impurities are mixed in from the external environment during the manufacturing process of the rinse liquid (e.g., contamination). When the entities to be counted are added to the rinse liquid, the abundance ratio may be adjusted for each specific size, taking into account the surface roughness of the object to be rinsed, etc.

[0042] The organic solvent (organic solvent (S1), the compound represented by the general formula (S1-1), and optionally the organic solvent (S2)) used in the rinse solution of this embodiment may be purified by a known method. The method for purifying the organic solvent is not particularly limited, and any known method can be used. Examples of the method for purifying the organic solvent include distillation purification. The organic solvent may be subjected to filtration through a filter, treatment with an ion exchange resin, or the like to reduce metal impurities, organic impurities, and the like. To reduce metal impurities, for example, filtration through a chelating filter, treatment with an ion exchange resin, or the like can be performed. To remove particulate impurities, for example, a polyethylene filter, a polypropylene filter, a polytetrafluoroethylene filter, a nylon filter, a polyimide filter, a polyamideimide filter, or a polyamide filter can be used. The purity of the organic solvent is preferably 99% or more, more preferably 99.5% or more, and even more preferably 99.9% or more.

[0043] <Storage container> The method for storing the rinse solution of this embodiment is not particularly limited, and a conventionally known storage container can be used. The void ratio and / or the type of gas to fill the voids in the container during storage may be appropriately determined so as to ensure the stability of the rinse solution. For example, the void ratio in the storage container may be about 0.01 to 30% by volume.

[0044] <Substrate> The rinse liquid of this embodiment is used to rinse a substrate having a convex portion. The substrate is not particularly limited, and any substrate known in the art can be used. The substrate may be any substrate used for manufacturing integrated circuit devices, optical devices, micromachines, precision mechanical devices, etc. Examples of the substrate include a silicon (Si) substrate, a silicon nitride (SiN) substrate, a silicon oxide (Ox) substrate, a silicon carbide (SiC) substrate, a tungsten (W) substrate, a tungsten carbide (WC) substrate, a cobalt (Co) substrate, a titanium nitride (TiN) substrate, a tantalum nitride (TaN) substrate, a germanium (Ge) substrate, a silicon germanium (SiGe) substrate, an aluminum (Al) substrate, a nickel (Ni) substrate, a titanium (Ti) substrate, a ruthenium (Ru) substrate, and a copper (Cu) substrate. Taking a silicon (Si) substrate as an example, the substrate may have a silicon oxide film such as a natural oxide film, a thermal oxide film, or a vapor phase synthesis film (such as a CVD film) formed on its surface, or may have a pattern formed on the silicon oxide film.

[0045] The substrate to which the rinse solution of this embodiment is applied has convex portions formed on its surface. The convex portions of the substrate may be linear or pillar-shaped. When the convex portions are pillar-shaped, the shape of the pillars is not particularly limited. Examples of the pillar shape include a cylindrical shape and a polygonal prism shape (such as a quadrangular prism shape).

[0046] The number of convex portions on the substrate is not particularly limited. The number of convex portions may be one or two or more. When there are two or more convex portions, there are concave portions between the convex portions, so it is also called a concave-convex pattern. The substrate preferably has a concave-convex pattern. An example of the uneven pattern is shown in Fig. 5. The uneven pattern 20 shown in Fig. 5 is composed of a plurality of convex portions 21 and a plurality of concave portions 22. The uneven pattern 20 is formed on the surface of the substrate 10.

[0047] The aspect ratio of the convex portions (concave-convex pattern) on the substrate is preferably 4 or more, more preferably 6 or more, even more preferably 8 or more, and particularly preferably 10 or more. The aspect ratio of the convex portions may be 11 or more, 12 or more, 13 or more, 14 or more, 15 or more, 16 or more, 17 or more, or 18 or more. The upper limit of the aspect ratio of the convex portions (concave-convex pattern) is not particularly limited, and examples include 30 or less, 25 or less, or 20 or less. The aspect ratio of the convex portions (concave-convex pattern) may be in the range of, for example, 4 to 30, 6 to 25, 8 to 25, 10 to 25, 15 to 25, or 15 to 20. The rinse liquid of this embodiment has a high effect of suppressing pattern collapse and is therefore suitable for use on substrates having convex portions with a high aspect ratio.

[0048] The size of the protrusions is not particularly limited. When the protrusions are pillar-shaped, the diameter of the pillars may be, for example, 10 to 50 nm, 15 to 30 nm, or 15 to 25 nm. When the convex portions are line-shaped, the line width may be, for example, 50 nm or less, 32 nm or less, or 22 nm or less. The substrate may have a line and space pattern (LS pattern). The line width and the line spacing of the LS pattern may be, for example, 50 nm or less, 32 nm or less, or 22 nm or less. The line width and the line spacing may be, for example, in the range of 10 to 50 nm, 15 to 32 nm, or 15 to 22 nm. The rinse solution of this embodiment has a high effect of suppressing pattern collapse, and can therefore be suitably used on substrates having fine patterns.

[0049] The convex portions of the substrate may be formed on the surface of an inorganic layer or on the surface of an organic layer. The substrate preferably has an inorganic pattern formed on the inorganic layer or an organic pattern formed on the organic layer.

[0050] An example of an inorganic pattern is an inorganic pattern formed by forming an etching mask on the surface of an inorganic layer present on a substrate by a photoresist method, followed by etching. Examples of the inorganic layer include the substrate itself, a layer made of an oxide of an element constituting the substrate, and a layer made of an inorganic substance such as silicon nitride, titanium nitride, or tungsten formed on the surface of the substrate. Examples of the inorganic layer include, but are not limited to, an inorganic layer formed during the manufacturing process of a semiconductor device.

[0051] Examples of organic patterns include resin patterns formed on a substrate by photolithography using a photoresist or the like. The organic pattern can be formed, for example, by forming an organic layer, which is a photoresist film, on a substrate, exposing the organic layer through a photomask, and developing it. The organic layer may be an organic layer formed on the surface of the substrate itself, or on the surface of a laminated film formed on the surface of the substrate. Examples of organic layers include, but are not limited to, organic films formed for etching or forming masks during the process of manufacturing a semiconductor device.

[0052] The rinse liquid of this embodiment is used to rinse the substrate before drying it. Figures 1 to 3 each show an example of a substrate processing method to which the rinse liquid of this embodiment is applied. 1, the substrate is treated with a chemical solution (stripping solution, cleaning solution, etching solution, etc.) in a chemical treatment step (S101), the substrate is rinsed with a water rinse solution in a water rinse step (S102), the substrate is rinsed with the rinse solution of this embodiment in a rinse step (S103), and the substrate is dried in a drying step (S104). As described above, the rinse solution of this embodiment is used in the rinse step (S103) immediately before the drying step (S104). 2, the substrate is treated with a chemical solution in a chemical treatment step (S201), the substrate is rinsed with a water rinse solution in a water rinsing step (S202), the substrate is treated with a solvent in a solvent treatment step (S203), the substrate is treated with a water repellent treatment using a water repellent agent in a water repellent treatment step (S204), the substrate is rinsed with the rinse solution of this embodiment in a rinsing step (S205), and the substrate is dried in a drying step (S206). As described above, the rinse solution of this embodiment is used in the rinsing step (S205) immediately before the drying step (S206). 3, the substrate is treated with a chemical solution in the chemical solution treatment step (S301), the substrate is rinsed with a water rinse solution in the water rinsing step (S302), the substrate is rinsed with the rinse solution of this embodiment in the rinsing step (S303), and the substrate is supercritically dried in the drying step (S304). As described above, the rinse solution of this embodiment is used in the rinsing step (S203) immediately before the supercritical drying step (S304).

[0053] When drying a substrate having a concave-convex pattern, the capillary force of the rinse liquid remaining in the pattern may cause the pattern to collapse. This is particularly likely to occur when the substrate has a pattern with a high aspect ratio. However, by rinsing the substrate with the rinse liquid of this embodiment before drying, it is possible to prevent pattern collapse during drying.

[0054] The rinse solution of this embodiment has a dynamic viscosity of 1.05×10 6 m 2 It is believed that by containing an organic solvent (S1) having a viscosity of 1 / s or less and having no hydroxyl groups or fluorine atoms, or by containing a compound represented by the general formula (S1-1), a uniform liquid film can be formed on the substrate surface. As a result, it is presumed that the rinse liquid remaining in the recesses of the pattern is removed uniformly during drying of the substrate, thereby suppressing pattern collapse. Furthermore, since the organic solvent (S1) or the compound represented by the general formula (S1-1) does not contain a fluorine atom, a substrate processing method with low environmental impact can be realized.

[0055] (Substrate processing method) A substrate processing method according to a third aspect of the present invention includes a step (A) of contacting a surface having convex portions of a substrate having convex portions with the rinse liquid according to the first or second aspect, and a step (B) of removing the rinse liquid from the surface having convex portions. The substrate processing method according to this aspect is applicable to substrates having convex portions.

[0056] <Process (A)> Step (A) is a step of bringing the surface of a substrate having convex portions into contact with the rinse liquid according to the first or second embodiment. The "substrate having convex portions" is the same as that explained in the above section "(Rinse liquid)." In step (A), a rinse solution is brought into contact with the surface of the substrate having the convex portions. The method for bringing the rinse solution into contact with the surface of the substrate is not particularly limited, and any known method can be used. Examples of such methods include spin coating, immersion (dipping), spraying, and puddling.

[0057] The spin coating method is a method in which a rinse liquid is supplied to a substrate while the substrate is being rotated using a spin coater, etc. Examples of methods for supplying the rinse liquid include a method in which the rinse liquid is sprayed onto the substrate and a method in which the rinse liquid is dripped onto the substrate. The immersion method (dip method) is a method in which the substrate is immersed in a rinse liquid. The spray method is a method in which a rinse liquid is sprayed into a transport space while the substrate is transported in a predetermined direction. The puddle method is a method in which a rinse liquid is raised by surface tension, placed on the substrate, and left to stand for a certain period of time.

[0058] The method for contacting the substrate surface with the rinse liquid is preferably spin coating, and examples of the spin rotation speed in spin coating include 100 to 5000 rpm, 500 to 3000 rpm, and 800 to 2000 rpm.

[0059] The temperature at which step (A) is carried out is not particularly limited, and examples of the temperature include 15 to 50° C. The contact time between the rinse liquid and the substrate is, for example, 10 seconds to 10 minutes, 20 seconds to 5 minutes, 30 to 250 seconds, and 60 to 200 seconds.

[0060] After forming a liquid film of the rinse liquid on the surface of the substrate, the substrate may be heated. By heating, a vapor film of the rinse liquid is formed between the liquid film and the upper surface of the substrate. The heating temperature may be, for example, 50 to 70°C. Heating may be carried out using a heating plate or the like.

[0061] <Process (B)> Step (B) is a step of removing the rinse liquid from the surface of the substrate having the protrusions. The substrate can be dried by completely removing the rinse liquid from the surface of the substrate, and therefore step (B) may be a step of drying the substrate.

[0062] The rinse liquid can be removed from the surface of the substrate by a known method, such as spin drying, nitrogen blow drying, and supercritical drying. Spin drying is a method in which the substrate is rotated to remove the rinse solution from the surface of the substrate by centrifugal force. Nitrogen blow drying is a method of blowing nitrogen gas onto the surface of the substrate to remove the rinse liquid from the surface of the substrate. Supercritical drying is a method of removing a rinse liquid from a substrate surface by contacting the surface with a supercritical fluid.

[0063] <Optional process> The method of the present embodiment may include optional steps in addition to the above steps (A) and (B), such as a chemical treatment step, a water rinsing step, a water-repellent treatment step, and a solvent treatment step.

[0064] <Chemical treatment process> The chemical treatment process is a process of treating a substrate with a desired chemical. The chemical can be selected appropriately depending on the type of substrate and the type of treatment. Examples of chemicals include, but are not limited to, stripping solutions for resists or adhesives, cleaning solutions, and etching solutions. Chemicals such as stripping solutions, cleaning solutions, and etching solutions have the effect of removing particles adhering to the substrate and removing residues after dry etching.

[0065] The chemical treatment is usually carried out on a surface of a substrate having convex portions (for example, a surface having a concave-convex pattern). The chemical treatment can be carried out by bringing the chemical solution into contact with the surface of the substrate having convex portions. The method for bringing the chemical solution into contact with the surface of the substrate is not particularly limited, and known methods can be used. Examples of the method for bringing the chemical solution into contact with the substrate include the same methods as those listed in the above step (A).

[0066] An example of the chemical treatment step is a cleaning step using a cleaning solution. The cleaning method in the cleaning step can be appropriately selected depending on the type of substrate to be cleaned, etc. As the cleaning method, any known method for cleaning a substrate can be used without any particular limitation. The cleaning method may be, for example, a cleaning method based on the well-known RCA cleaning method. In the RCR cleaning method, the substrate is first immersed in an SC-1 solution of hydrogen peroxide and ammonium hydroxide to remove fine particles and organic matter from the substrate. Next, the substrate is immersed in an aqueous hydrofluoric acid solution to remove the native oxide film on the substrate surface. After that, the substrate is immersed in an acidic solution of SC-2 solution of hydrogen peroxide and dilute hydrochloric acid to remove alkali ions and metal impurities that are insoluble in the SC-1 solution.

[0067] <Water rinsing process> The water rinse step is a step of rinsing the substrate with a water rinse liquid. The water rinse step is usually performed after the chemical treatment step to remove the chemical liquid adhering to the substrate surface. In this case, the chemical liquid adhering to the substrate surface is replaced and removed with the water rinse liquid.

[0068] The water rinsing step can be carried out by contacting the surface of the substrate having convex portions (for example, a surface having a concave-convex pattern) with a water rinsing liquid. The method for contacting the water rinsing liquid with the surface of the substrate is not particularly limited, and known methods can be used. Examples of the method for contacting the water rinsing liquid with the substrate include the same methods as those listed in the above step (A).

[0069] The temperature at which the water rinse is carried out is not particularly limited, and examples of the temperature include 15 to 80° C. The contact time between the substrate and the water rinse solution includes, for example, 10 seconds to 10 minutes, 20 seconds to 5 minutes, 30 to 250 seconds, and 50 to 200 seconds.

[0070] The water rinse solution used in the water rinse step contains water. The water used as the water rinse solution is preferably purified water such as distilled water, ion-exchanged water, or ultrapure water, and more preferably ultrapure water commonly used in semiconductor manufacturing. The water may contain trace components that are inevitably mixed in. The water content in the water rinse liquid is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on the total mass of the water rinse liquid. The water content in the water rinse liquid may be 100% by mass. That is, the water rinse liquid may be water.

[0071] The water rinse may contain optional components in addition to water, such as known additives such as surfactants, and organic solvents. Examples of the organic solvent include hydrocarbon solvents, ester solvents, ether solvents, ketone solvents, halogen-containing solvents, sulfoxide solvents, alcohol solvents, polyhydric alcohol derivatives, nitrogen-containing compound solvents, etc. The organic solvent is preferably a water-soluble organic solvent. Examples of the surfactant include a fluorine-based surfactant and a silicone-based surfactant.

[0072] Specific examples of fluorine-based surfactants include commercially available fluorine-based surfactants such as BM-1000 and BM-1100 (all manufactured by BM Chemie), Megafac F142D, Megafac F172, Megafac F173, and Megafac F183 (all manufactured by DIC Corporation), Fluorad FC-135, Fluorad FC-170C, Fluorad FC-430, and Fluorad FC-431 (all manufactured by Sumitomo 3M Limited), Surflon S-112, Surflon S-113, Surflon S-131, Surflon S-141, and Surflon S-145 (all manufactured by Asahi Glass Co., Ltd.), SH-28PA, SH-190, SH-193, SZ-6032, and SF-8428 (all manufactured by Toray Silicones Co., Ltd.).

[0073] Specific examples of silicone surfactants that can be preferably used include unmodified silicone surfactants, polyether-modified silicone surfactants, polyester-modified silicone surfactants, alkyl-modified silicone surfactants, aralkyl-modified silicone surfactants, and reactive silicone surfactants. The silicone surfactant may be a commercially available silicone surfactant, and specific examples of commercially available silicone surfactants include Paintad M (manufactured by Dow Corning Toray Co., Ltd.), Topika K1000, Topika K2000, and Topika K5000 (all manufactured by Takachiho Sangyo Co., Ltd.), XL-121 (a polyether-modified silicone surfactant manufactured by Clariant), and BYK-310 (a polyester-modified silicone surfactant manufactured by BYK-Chemie).

[0074] <Water-repellent treatment process> The water-repellent treatment step is a step of performing a water-repellent treatment on the substrate. By performing the water-repellent treatment on the substrate, the surface of the substrate becomes water-repellent, and moisture remaining on the substrate surface is suppressed.

[0075] The water-repellent treatment step can be carried out by contacting a water-repellent agent with a surface of a substrate having convex portions (for example, a surface having a concave-convex pattern). The method for contacting the water-repellent agent with the surface of the substrate is not particularly limited, and known methods can be used. Examples of methods for contacting the water-repellent agent with the substrate include the methods listed in step (A) above and a method of contacting the surface of the substrate with the vapor of the water-repellent agent.

[0076] The water repellent agent is not particularly limited, and may be selected from those generally used for water repellent treatments depending on the material of the substrate. Examples of water repellent agents include those containing a silylating agent.

[0077] The silylating agent is not particularly limited, and known silylating agents can be used without any particular limitation. Specifically, for example, a silylating agent represented by any of the following general formulas (1) to (3) can be used. In the following general formulas (1) to (3), the alkyl group has 1 to 5 carbon atoms, the cycloalkyl group has 5 to 10 carbon atoms, the alkoxy group has 1 to 5 carbon atoms, and the heterocycloalkyl group has 5 to 10 carbon atoms.

[0078] [ka] [In formula (1), R 1 represents a hydrogen atom or a saturated or unsaturated alkyl group, and R 2 represents a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, or a saturated or unsaturated heterocycloalkyl group. 1 and R 2 may be bonded to each other to form a saturated or unsaturated heterocycloalkyl group having a nitrogen atom.

[0079] [ka] [In formula (2), R 3 represents a hydrogen atom, a methyl group, a trimethylsilyl group, or a dimethylsilyl group, and R 4 ,R 5 each independently represents a hydrogen atom, an alkyl group, or a vinyl group.

[0080] [ka] [In formula (3), X represents O, CHR 7 , CHOR 7 , C.R. 7 R 7 , or NR 8 indicates R 6 ,R 7 each independently represents a hydrogen atom, a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, a trialkylsilyl group, a trialkylsiloxy group, an alkoxy group, a phenyl group, a phenethyl group, or an acetyl group; R 8 represents a hydrogen atom, an alkyl group, or a trialkylsilyl group.

[0081] Examples of the silylating agent represented by the above formula (1) include N,N-dimethylaminotrimethylsilane, N,N-diethylaminotrimethylsilane, t-butylaminotrimethylsilane, allylaminotrimethylsilane, trimethylsilylacetamide, trimethylsilylpiperidine, trimethylsilylimidazole, trimethylsilylmorpholine, 3-trimethylsilyl-2-oxazolidinone, trimethylsilylpyrazole, trimethylsilylpyrrolidine, 2-trimethylsilyl-1,2,3-triazole, and 1-trimethylsilyl-1,2,4-triazole.

[0082] Examples of the silylating agent represented by the above formula (2) include hexamethyldisilazane, N-methylhexamethyldisilazane, 1,2-di-N-octyltetramethyldisilazane, 1,2-divinyltetramethyldisilazane, heptamethyldisilazane, nonamethyltrisilazane, and tris(dimethylsilyl)amine.

[0083] Examples of the silylating agent represented by the above formula (3) include trimethylsilyl acetate, trimethylsilyl propionate, trimethylsilyl butyrate, and trimethylsilyloxy-3-penten-2-one.

[0084] The silylating agent can be used by dissolving it in an appropriate solvent. The solvent for the silylating agent is not particularly limited, and can be appropriately selected from those that can dissolve the silylating agent and cause minimal damage to the pattern. Specific examples of the solvent for the silylating agent include sulfoxides such as dimethyl sulfoxide; sulfones such as dimethyl sulfone, diethyl sulfone, bis(2-hydroxyethyl) sulfone, and tetramethylene sulfone; amides such as N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, N-methylacetamide, and N,N-diethylacetamide; N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, and N-hydroxymethyl-2-pyrrolidone. lactams such as 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, and N-hydroxyethyl-2-pyrrolidone; imidazolidinones such as 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, and 1,3-diisopropyl-2-imidazolidinone; dialkyl ethers such as dimethyl ether, diethyl ether, methyl ethyl ether, dipropyl ether, diisopropyl ether, and dibutyl ether; dimethyl glycol, dimethyl diglycol, dimethyl triglycol, methyl ethyl diglycol, and diethyl ketones such as methyl ethyl ketone, cyclohexanone, 2-heptanone, and 3-heptanone; terpenes such as p-menthane, diphenylmenthane, limonene, terpinene, bornane, norbornane, and pinane; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, and dipropylene glycol monoacetate, and derivatives of polyhydric alcohols such as monoalkyl ethers (e.g., monomethyl ether, monoethyl ether, monopropyl ether, and monobutyl ether) or monophenyl ethers of the above polyhydric alcohols or compounds having an ester bond [e.g., propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME)]; and the like.

[0085] The concentration of the silylating agent in the water repellent agent is, for example, 0.1 to 50% by mass, preferably 0.5 to 30% by mass, and more preferably 1.0 to 20% by mass, relative to the total mass of the water repellent agent. By setting the concentration of the silylating agent within this range, the coatability of the silylating agent can be ensured, and the water repellent effect on the substrate surface can be easily obtained.

[0086] The temperature for performing the water repellent treatment is not particularly limited, and examples of the temperature include 15 to 50° C. The contact time between the substrate and the water repellent agent is, for example, 10 seconds to 10 minutes, 20 seconds to 5 minutes, 30 to 250 seconds, and 50 to 200 seconds.

[0087] <Solvent treatment process> The solvent treatment step is a step of treating the substrate with a solvent. The solvent treatment step is performed, for example, before the water-repellent treatment step, in order to remove the water rinse liquid adhering to the surface of the substrate. In this case, the water rinse liquid adhering to the surface of the substrate is replaced with the solvent and removed.

[0088] The solvent treatment step can be carried out by bringing a solvent into contact with the surface of the substrate having convex portions (for example, a surface having a concave-convex pattern). The method for bringing the solvent into contact with the surface of the substrate is not particularly limited, and known methods can be used. Examples of the method for bringing the solvent into contact with the substrate include the same methods as those listed in the above step (A).

[0089] The temperature for carrying out the solvent treatment is not particularly limited, and examples of the temperature include 15 to 80° C. The contact time between the substrate and the solvent is, for example, 10 seconds to 10 minutes, 20 seconds to 5 minutes, 30 to 250 seconds, and 50 to 200 seconds.

[0090] The solvent used in the solvent treatment step can be appropriately selected depending on the type of substrate and / or the type of water repellent. Examples of the solvent include the organic solvent (S2) described above. Examples of the solvent include alcohol-based solvents. Specific examples of alcohol-based solvents include 2-propanol.

[0091] <Processing example (1)> 1 is a flow diagram showing a substrate processing example (1) to which the substrate processing method of this embodiment is applied. In the processing example (1), the substrate is processed in the order of a chemical liquid processing step (S101), a water rinsing step (S102), a rinsing step (S103), and a drying step (S104). In the processing example (1), the rinsing step (S103) corresponds to the above-mentioned step (A), and the drying step (S104) corresponds to the above-mentioned step (B). Other processing may or may not be performed between the steps shown in Fig. 1. It is preferable that other processing is not performed between the steps shown in Fig. 1. It is preferable that the surface of the substrate having the convex portions is not dried between the steps shown in Fig. 1. In other words, it is preferable that the substrate to which the treatment liquid from the previous step has adhered is brought into contact with the treatment liquid from the subsequent step, and the treatment liquid from the previous step adhering to the substrate is replaced with the treatment liquid from the subsequent step. For example, processing example (1) can be performed as follows: In the chemical processing step (S101), a substrate is processed with a chemical. In the water rinsing step (S102), a water rinsing liquid is supplied to the substrate, and the chemical liquid remaining on the substrate is replaced with the water rinsing liquid. In the rinsing step (S103), a rinsing liquid is supplied to the substrate, and the water rinsing liquid remaining on the substrate is replaced with the rinsing liquid. In the drying step (S104), the rinsing liquid remaining on the substrate is removed, and the substrate is dried.

[0092] <Processing example (2)> 2 is a flow diagram showing a substrate processing example (2) to which the substrate processing method of this embodiment is applied. In the processing example (2), the substrate is processed in the following order: a chemical solution processing step (S201), a water rinsing step (S202), a solvent processing step (S203), a water repellent processing step (S204), a rinsing step (S205), and a drying step (S206). In the processing example (2), the rinsing step (S205) corresponds to the above-mentioned step (A), and the drying step (S206) corresponds to the above-mentioned step (B). Other processing may or may not be performed between the steps shown in Fig. 2. It is preferable that other processing is not performed between the steps shown in Fig. 2. It is preferable that the surface of the substrate having the convex portions is not dried between the steps shown in Fig. 2. In other words, it is preferable that the substrate to which the treatment liquid from the previous step has adhered is brought into contact with the treatment liquid from the subsequent step, and the treatment liquid from the previous step adhering to the substrate is replaced with the treatment liquid from the subsequent step. For example, processing example (2) can be performed as follows: In the chemical processing step (S201), a substrate is processed with a chemical. In the water rinsing step (S202), a water rinsing liquid is supplied to the substrate, and the chemical liquid remaining on the substrate is replaced with the water rinsing liquid. In the solvent processing step (S203), a solvent is supplied to the substrate, and the water rinsing liquid remaining on the substrate is replaced with the solvent. In the water repellent processing step (S204), a water repellent agent is supplied to the substrate, and the solvent remaining on the substrate is replaced with the water repellent agent. In the rinsing step (S205), a rinsing liquid is supplied to the substrate, and the water repellent agent remaining on the substrate is replaced with the rinsing liquid. In the drying step (S206), the rinsing liquid remaining on the substrate is removed, and the substrate is dried.

[0093] <Processing example (3)> 3 is a flow diagram showing a substrate processing example (3) to which the substrate processing method of this embodiment is applied. In the processing example (3), the substrate is processed in the following order: a chemical liquid processing step (S301), a water rinsing step (S302), a rinsing step (S303), and a supercritical drying step (S304). In the processing example (3), the rinsing step (S303) corresponds to the above-mentioned step (A), and the supercritical drying step (S304) corresponds to the above-mentioned step (B). Other processing may or may not be performed between the steps shown in Fig. 3. It is preferable that other processing is not performed between the steps shown in Fig. 3. It is preferable that the surface of the substrate having the convex portions is not dried between the steps shown in Fig. 3. In other words, it is preferable that the substrate to which the treatment liquid from the previous step has adhered is brought into contact with the treatment liquid from the subsequent step, and the treatment liquid from the previous step adhering to the substrate is replaced with the treatment liquid from the subsequent step. For example, processing example (3) can be performed as follows: In the chemical processing step (S301), a substrate is treated with a chemical. In the water rinsing step (S302), a water rinsing liquid is supplied to the substrate, and the chemical liquid remaining on the substrate is replaced with the water rinsing liquid. In the rinsing step (S303), a rinsing liquid is supplied to the substrate, and the water rinsing liquid remaining on the substrate is replaced with the rinsing liquid. In the supercritical drying step (S304), the rinsing liquid remaining on the substrate is removed, and the substrate is dried.

[0094] ≪Supercritical drying process (S304)≫ Fig. 4 is a flow diagram showing an example of supercritical drying. Supercritical drying can be carried out in a chamber that can be heated and pressurized to a supercritical state. The chamber can be, for example, a high-pressure vessel made of stainless steel that has a predetermined pressure resistance.

[0095] Supercritical fluid contact process (S401): The supercritical fluid contacting step is a step of bringing a supercritical fluid into contact with a surface of a substrate having convex portions (for example, a surface having a concave-convex pattern). A supercritical fluid is a substance in a supercritical state. The supercritical state is the state of a substance when it is placed under a temperature and pressure above its critical point. A supercritical fluid has both the diffusibility of a gas and the solubility of a liquid. Examples of processing fluids used as supercritical fluids include carbon dioxide and hydrofluoroether (HFE).

[0096] The method for contacting the supercritical fluid with the substrate is not particularly limited, and known methods can be used. For example, the substrate is placed in a chamber, a liquid processing fluid is supplied into the chamber, and the liquid processing fluid is brought into contact with the surface of the substrate having a convex portion. As a result, the rinse liquid adhering to the surface of the substrate dissolves in the processing fluid. Next, the temperature and pressure inside the chamber are raised to a temperature and pressure equal to or higher than the critical point of the processing fluid, thereby converting the processing fluid into a supercritical fluid. This allows the supercritical fluid to come into contact with the surface of the substrate (the rinse liquid adhering to the surface of the substrate). When the processing fluid is carbon dioxide, liquefied carbon dioxide can be used as the processing fluid in a liquid state. Conditions for turning liquefied carbon dioxide into a supercritical fluid include, for example, a temperature of 35° C. and a pressure of 7.5 MPa.

[0097] By using an organic solvent that is highly compatible with the processing fluid as the (S1) component, the solubility of the rinse liquid in the processing fluid is improved. Therefore, the rinse liquid can be easily removed in the rinse liquid removal step described below. The compatibility with the processing fluid can be determined, for example, by the similarity of the Hansen solubility parameters. For example, when carbon dioxide is used as the processing fluid, it is preferable to use an organic solvent that has a Hansen solubility parameter similar to that of carbon dioxide as the (S1) component.

[0098] Supercritical fluid removal process (S402): The supercritical fluid removal step is a step of removing the supercritical fluid from a surface of a substrate having protrusions (for example, a surface having a concave-convex pattern). By removing the supercritical fluid from the surface of the substrate, the rinse liquid dissolved in the supercritical fluid is also removed.

[0099] The method for removing the supercritical fluid from the surface of the substrate is not particularly limited, and any known method can be used. For example, a method for removing the supercritical fluid from the chamber while depressurizing the chamber can be used.

[0100] The method of this embodiment is not limited to the above processing examples (1) to (3), and any steps can be adopted in any order as long as it includes the above steps (A) and (B).

[0101] In the substrate processing method of this embodiment, step (A) is performed using the rinse solution according to the first or second aspect. This makes it possible to suppress pattern collapse when the rinse solution is removed from the surface of the substrate in step (B). Therefore, the substrate processing method of this embodiment can be suitably applied to substrates having a concave-convex pattern with a high aspect ratio that is prone to pattern collapse.

[0102] (Method of manufacturing semiconductor devices) A method for manufacturing a semiconductor device according to a fourth aspect of the present invention includes a step of treating a substrate having a convex portion by the method for treating a substrate having a convex portion according to the third aspect.

[0103] <Substrate processing process> The step of treating the substrate can be carried out in the same manner as described above in the section "(Substrate Treatment Method)".

[0104] <Optional process> The method for manufacturing a semiconductor device according to this embodiment may include optional steps in addition to the substrate processing step. The optional steps are not particularly limited and include known steps performed during the manufacture of semiconductor devices. Examples of such steps include, but are not limited to, capacitor formation, channel formation, high-K / metal gate formation, metal wiring, gate structures, source structures, drain structures, insulating layers, ferromagnetic layers, and nonmagnetic layers (layer formation, etching other than the above-described etching process, chemical mechanical polishing, modification, etc.), resist film formation, exposure, development, heat treatment, cleaning, and inspection. These other steps may be performed before or after the substrate processing step, as needed.

[0105] In the semiconductor manufacturing method of this embodiment, the substrate is processed by the substrate processing method according to the third aspect, so that pattern collapse during the processing can be suppressed, thereby enabling efficient manufacturing of semiconductor devices. [Example]

[0106] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0107] <Selection of organic solvent> In order to create a rinse solution that is more effective at suppressing pattern collapse than 2-propanol (IPA), the physical properties of various organic solvents were compared. Among the physical properties, we focused on dynamic viscosity and selected organic solvents with lower dynamic viscosity than 2-propanol. The physical properties of the selected organic solvents are shown in Tables 1 to 3.

[0108] [Table 1]

[0109] [Table 2]

[0110] [Table 3]

[0111] The physical properties shown in Tables 1 to 3 were as follows. The boiling points and melting points are measured values, except for 1,1,1-trimethoxypropane, 1,2,3-trimethoxypropane, and 1,1,3-trimethoxypropane, which are estimated values ​​using HSPiP. The surface tension was calculated using HSPiP. The densities shown are actual measurements using a density meter (DA-650, Endo Scientific Co., Ltd.), except for 1,1,1-trimethoxypropane, 1,2,3-trimethoxypropane, and 1,1,3-trimethoxypropane, which were estimated using HSPiP. The viscosity values ​​shown are actual measurements using a viscometer (VMC-252, Rigosha Co., Ltd.), except for 1,1,1-trimethoxypropane, 1,2,3-trimethoxypropane, and 1,1,3-trimethoxypropane, which were estimated using HSPiP. The dynamic viscosity was calculated using the following formula. Dynamic viscosity (m 2 / s)=viscosity(cp) / density(g / ml) The critical temperatures were calculated by the Joback method. The latent heat of vaporization at the boiling point is shown as an estimated value using the Joback method and a literature value listed in Scifinder. The latent heat of vaporization at 25°C and 60°C was estimated using the Watson equation. The Hansen solubility parameters were estimated by HSPiP.

[0112] <Preparation of rinse solution> (Examples 1 to 4, Comparative Example 1) Rinse solutions were prepared for each example as shown in Table 4. In Table 4, the values ​​in brackets [ ] indicate the mass % relative to the total mass of the rinse solution.

[0113] [Table 4]

[0114] <Substrate processing method (1)> The substrate used was a 12-inch silicon wafer with a pattern of pillars spaced 100 nm apart. The pillars had an aspect ratio of 18.5 and a diameter of 20 nm. A 2 cm x 1 cm wafer piece was prepared and subjected to the following treatments in order. The wafer piece was prevented from drying out between treatments with each chemical solution. 1. Immerse in dilute hydrofluoric acid (DHF; HF:water = 1:100) for 30 seconds. 2. Immerse in ultrapure water (UPW) for 60 seconds. 3. Immerse in each rinse solution for 60 seconds. 4. Nitrogen blow drying.

[0115] <Evaluation of Pattern Collapse (1)> Top-down observation was performed using a scanning electron microscope S-9220 (accelerating voltage 800V, Hitachi High-Technologies Corporation). Three SEM images were taken for each wafer piece treated with each rinse solution, and the number of fallen pillars was counted. Because pillar collapse varied from the center to the edge of the chip, the number of fallen pillars in structures obtained from essentially the same center-to-edge distance was counted. The results are shown in Table 5 as the "number of fallen pillars." A smaller number of fallen pillars indicates better collapse prevention.

[0116] [Table 5]

[0117] The results in Table 5 show that in Examples 1 to 4, the number of collapsed pillars was significantly reduced compared to Comparative Example 1.

[0118] <Preparation of rinse solution> (Examples 5 to 9, Comparative Example 2) Rinse solutions were prepared for each example as shown in Table 6. In Table 6, the values ​​in brackets [ ] indicate the mass % relative to the total mass of the rinse solution.

[0119] [Table 6]

[0120] <Substrate processing method (2)> The substrate used was a silicon wafer with a pattern of pillars spaced 100 nm apart, with an aspect ratio of 18.5 and a diameter of 20 nm. While the substrate was being spun (at 1000 rpm and room temperature (20° C.) for 1 minute), the following chemical solutions were supplied in order onto the patterned surface to treat the substrate surface. 1. Treat with dilute hydrofluoric acid (DHF; HF:water = 1:100) for 30 seconds. 2. Treat with ultrapure water (UPW) for 60 seconds. 3. Treat with the rinse solution of each example at 75°C for 60 seconds. 4. Nitrogen blow drying.

[0121] <Evaluation of Pattern Collapse (2)> Top-down observation was performed using a scanning electron microscope S-9220 (accelerating voltage 800V, Hitachi High-Technologies Corporation). Three SEM images were taken for each wafer treated with each rinse solution, and the number of fallen pillars was counted. Because pillar collapse varied from the center to the edge of the chip, the number of fallen pillars in structures obtained from essentially the same center-to-edge distance was counted. The results are shown in Table 6 as the "number of fallen pillars." A smaller number of fallen pillars indicates better collapse prevention.

[0122] [Table 7]

[0123] The results in Table 7 show that the number of collapsed pillars was significantly reduced in Examples 5 to 9 compared to Comparative Example 2. Among the Examples, the number of collapsed pillars tended to be lower when a rinse solution not containing IPA was used (Examples 5 to 7) than when a rinse solution containing IPA was used (Examples 8 and 9). [Explanation of symbols]

[0124] 10 Substrate 20 Concave and Convex Pattern 21 Convex part 22 recess

Claims

1. A rinse solution for rinsing a substrate having a convex portion, comprising a compound represented by the following general formula (S1-1), the content of the compound being 50 mass %: 【Chemistry 2】 [In the formula, R １ represents a linear or branched saturated aliphatic hydrocarbon group having 3 carbon atoms; and n1 represents 2 or 3.

2. 2. The rinse solution according to claim 1, wherein the compound represented by general formula (S1-1) is selected from the group consisting of dimethoxypropane and trimethoxypropane.

3. The rinse liquid according to claim 1 , which is used to rinse the substrate before drying it.

4. a step (A) of contacting a surface of a substrate having convex portions with the rinse liquid according to any one of claims 1 to 3; a step (B) of removing the rinse liquid from the surface having the convex portions; A method for treating a substrate having a protrusion, comprising:

5. 5. The method for treating a substrate having a convex portion according to claim 4, wherein the step (B) is a step of drying the substrate.

6. A method for manufacturing a semiconductor device, comprising the step of treating a substrate having a convex portion by the method for treating a substrate having a convex portion according to claim 4 or 5.

Images