Substrate processing method, chemical solution, and chemical solution providing method

Abstract

The present invention provides a method for method substrates, for processing the surface of a substrate having an uneven pattern formed on the surface, the method having: a rinsing step S101 for rinsing the surface of the substrate with a rinsing liquid that contains water; a chemical solution replacement step S102 for bringing a chemical solution into contact with the rinsed surface of the substrate, and replacing liquid adhering to the surface of the substrate from the rinsing liquid to the chemical solution; a state change step S103 for raising the temperature of the substrate wetted by the chemical solution to the critical temperature of the chemical solution or higher to bring the chemical solution into a supercritical state; and, a removal step S104 for removing the chemical solution in the supercritical state from the surface of the substrate, the chemical solution containing an organic solvent (S1) having a greater specific gravity than water (excluding, however, organic solvents having fluorine atoms).

Description

[Technical Field]

[0001] The present invention relates to a substrate processing method, a chemical solution, and a method for providing the chemical solution. This application claims priority to US 63 / 250,239, filed in the United States on September 30, 2021, the contents of which are incorporated herein by reference. [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] On the other hand, in semiconductor manufacturing processes, contamination by particles and the like causes a decrease in manufacturing yield. Therefore, substrates are cleaned with a rinse solution to remove particles and the like adhering to the substrate. After a substrate on which a pattern has been formed is cleaned with a rinse solution, the rinse solution is removed by drying the substrate. However, during this process, the pattern on the substrate surface may collapse due to the capillary force of the rinse solution remaining in the pattern.

[0004] To solve this problem, a method called supercritical drying, which uses a supercritical fluid with a surface tension of nearly zero, has been proposed. Since no gas-liquid interface is formed, the surface of the substrate can be dried without the application of capillary forces.

[0005] For example, Patent Document 1 proposes a method for treating a semiconductor substrate, in which the surface of the semiconductor substrate is washed with an aqueous cleaning solution, and the aqueous cleaning solution adhering to the substrate surface is replaced with a supercritical fluid and then dried, characterized in that the fluid used is a solvent containing a fluorine-containing alcohol having 2 to 6 carbon atoms, and in which the contents of each of the elements Fe, Ni, Cr, Al, Zn, Cu, Mg, Li, K, Na, and Ca are each 500 ppb by mass or less. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-92285 Summary of the Invention [Problem to be solved by the invention]

[0007] The method for treating semiconductor substrates described in Patent Document 1 uses a fluorine-containing alcohol having 2 to 6 carbon atoms as a solvent. However, the fluorine-containing alcohol is not very versatile as a solvent, is not easily available, and has a high global warming potential, so there remain issues with its application to mass production.

[0008] Isopropyl alcohol (IPA) is also commonly used as a supercritical fluid, but IPA easily absorbs moisture from the atmosphere and easily traps external impurities, which can cause pattern collapse.

[0009] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a substrate processing method that has a good effect of suppressing pattern collapse when processing the surface of a substrate on which a concave-convex pattern is formed, a chemical solution to be used in the substrate processing method, and a method for providing the chemical solution. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention employs the following configuration. That is, a first aspect of the present invention is a substrate processing method for processing the surface of a substrate having a pattern of protrusions and recesses formed on its surface, the method comprising: a rinsing step of rinsing the surface of the substrate with a rinsing liquid containing water; a chemical liquid replacement step of contacting the rinsed surface of the substrate with a chemical liquid and replacing the liquid adhering to the surface of the substrate from the rinsing liquid with the chemical liquid; a state change step of raising the temperature of the substrate wetted with the chemical liquid to a temperature equal to or higher than the critical temperature of the chemical liquid to bring the chemical liquid into a supercritical state; and a removal step of removing the chemical liquid in the supercritical state from the surface of the substrate, wherein the chemical liquid contains an organic solvent (S1) having a specific gravity greater than that of water (excluding organic solvents having fluorine atoms).

[0011] A second aspect of the present invention is a chemical solution used in a substrate processing method, the method comprising: a rinsing step of rinsing the surface of a substrate having a textured pattern formed thereon with a rinsing solution containing water; a chemical solution substitution step of bringing a chemical solution into contact with the surface of the rinsed substrate and substituting the rinsing solution for the liquid adhering to the surface of the substrate; a state change step of raising the temperature of the substrate wetted with the chemical solution to a temperature equal to or higher than the critical temperature of the chemical solution to bring the chemical solution into a supercritical state; and a removal step of removing the chemical solution in the supercritical state from the surface of the substrate. The chemical solution contains an organic solvent (S1) having a specific gravity greater than that of water (excluding organic solvents having fluorine atoms).

[0012] A third aspect of the present invention is a method for providing a chemical solution, which provides the chemical solution to a process line that performs the substrate processing method according to the first aspect of the present invention. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a substrate processing method that has a good effect of suppressing pattern collapse when processing the surface of a substrate on which a concave-convex pattern is formed, a chemical solution used in the substrate processing method, and a method for providing the chemical solution. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a flow chart of a substrate processing method according to the first embodiment. [Figure 2] FIG. 10 is a flowchart of a substrate processing method according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] (Substrate processing method) A first aspect of the present invention is a substrate processing method for processing the surface of a substrate having a pattern of protrusions and recesses formed on its surface, the method comprising: a rinsing step of rinsing the surface of the substrate with a rinse liquid containing water; a chemical liquid replacement step of contacting the rinsed surface of the substrate with a chemical liquid to replace the liquid adhering to the surface of the substrate from the rinse liquid with the chemical liquid; a state change step of raising the temperature of the substrate wetted with the chemical liquid to a temperature equal to or higher than the critical temperature of the chemical liquid to bring the chemical liquid into a supercritical state; and a removal step of removing the chemical liquid in the supercritical state from the surface of the substrate, wherein the chemical liquid contains an organic solvent (S1) having a specific gravity greater than that of water (excluding organic solvents having fluorine atoms).

[0016] The substrate is not particularly limited, and conventionally known substrates can be used, such as 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.

[0017] The term "surface" refers to the surface of the substrate itself, as well as the surface of an inorganic pattern provided on the substrate, and the surface of an unpatterned inorganic layer.

[0018] An example of an inorganic pattern provided on a substrate is an inorganic pattern formed by forming an etching mask on the surface of an inorganic layer present on the substrate by a photoresist method, followed by etching. Examples of inorganic layers 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 such inorganic layers include, but are not limited to, inorganic layers formed during the manufacturing process of semiconductor devices.

[0019] The shape of the pattern is not particularly limited, and may be, for example, a pattern shape generally formed in a semiconductor manufacturing process. The pattern shape may be a line pattern, a hole pattern, or a pattern including a plurality of pillars. The pattern shape is preferably a pattern including a plurality of pillars. The shape of the pillar is not particularly limited, and examples thereof include a cylindrical shape, a polygonal prism shape (such as a quadrangular prism shape), etc.

[0020] First Embodiment FIG. 1 shows a flow diagram of a substrate processing method according to the first embodiment. The substrate processing method of this embodiment includes a rinsing step S101 of rinsing the surface of the substrate with a rinse liquid containing water, a chemical liquid replacement step S102 of bringing a chemical liquid into contact with the surface of the rinsed substrate and replacing the liquid adhering to the surface of the substrate from the rinse liquid with the chemical liquid, a state change step S103 of raising the temperature of the substrate wetted with the chemical liquid to a temperature equal to or higher than the critical temperature of the chemical liquid to bring the chemical liquid into a supercritical state, and a removal step S104 of removing the chemical liquid in the supercritical state from the surface of the substrate.

[0021] [Rinse process S101] The rinsing step S101 is a step of rinsing the surface of the substrate with a rinsing liquid containing water. The rinsing method is not particularly limited, and any method commonly used for cleaning substrates in semiconductor manufacturing processes can be used, such as spin coating, immersion (dipping), spraying, and puddling, which will be described later.

[0022] The spin coating method is a method in which a substrate is rotated using a spin coater or the like, and a rinse liquid is dripped or sprayed onto the rotating 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 the substrate is transported in a predetermined direction and a rinse liquid is sprayed into the space. The puddle method is a method in which a rinse liquid is piled up on the substrate by surface tension and left standing for a certain period of time.

[0023] Among the above methods, the rinsing step S101 is preferably performed by spin coating. The rotation speed of the spinning is, for example, 100 rpm or more and 5000 rpm or less.

[0024] Rinse liquid The rinse liquid used in the rinse step S101 includes water, which may be pure water, deionized water, ion-exchanged water, or the like. The rinse liquid in this embodiment may contain an organic solvent in addition to water.

[0025] Examples of the organic solvent include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, alcohols, polyhydric alcohol derivatives, and nitrogen-containing compound solvents.

[0026] The rinse liquid may further contain known additives, etc. Known additives include, for example, fluorine-based surfactants and silicone-based surfactants.

[0027] 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.).

[0028] 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).

[0029] [Chemical solution replacement process S102] The chemical liquid replacement step S102 is a step of bringing a chemical liquid into contact with the surface of the substrate rinsed in the above-described rinsing step S101, and replacing the liquid adhering to the surface of the substrate from the rinse liquid with the chemical liquid.

[0030] In the substrate processing method of this embodiment, at least the chemical liquid substitution step S102 and the state change step S103, which will be described later, are performed in the same chamber. The chamber is, for example, a high-pressure vessel made of stainless steel and having a predetermined pressure resistance.

[0031] The method for bringing the chemical solution into contact with the surface of the substrate is not particularly limited, and examples thereof include the above-mentioned spin coating method, immersion method (dip method), spray method, and puddle method.

[0032] <Chemical solution> The chemical solution in the chemical solution replacement step S102 contains an organic solvent (S1) having a specific gravity greater than that of water, except for organic solvents containing fluorine atoms. From the viewpoint of reducing costs and environmental impact, the chemical solution in this embodiment preferably does not contain an organic solvent having a fluorine atom.

[0033] <Organic solvent (S1)> The organic solvent (S1) in this embodiment is not particularly limited as long as it does not contain a fluorine atom and has a specific gravity greater than that of water, but polar solvents such as carbonate-based solvents and lactone-based solvents are preferred. In this specification, the "specific gravity" is a value calculated using water at 4°C as the standard substance.

[0034] Specific examples of the organic solvent (S1) in this embodiment include propylene carbonate (propylene carbonate, specific gravity: 1.2047, solubility: 29.3), dimethyl carbonate (dimethyl carbonate, specific gravity: 1.0636, solubility: 8.5), ethylene carbonate (ethylene carbonate, specific gravity: 1.3214, solubility: 29.3), diethyl carbonate (diethyl carbonate, specific gravity: 1.069, solubility: 1.8), and butylene carbonate (butylene carbonate, specific gravity: 1.107, solubility: 8.5). Suitable examples include furfuryl alcohol (specific gravity: 1.1296, solubility: 7.7), tetrahydrofurfuryl alcohol (specific gravity: 1.0544, solubility: 16.9), dihydrolevoglucosenone (silene, specific gravity: 1.261, solubility: 3.2), γ-butyrolactone (specific gravity: 1.1284, solubility: 7.0), γ-valerolactone (specific gravity: 1.05474, solubility: 3.5), and δ-valerolactone (specific gravity: 1.113, solubility: 4.3). The solubility of each of the organic solvents (S1) is a solubility (g / 100 mL) that indicates how many grams of water can be dissolved in 100 mL of each organic solvent (S1) at 25°C.

[0035] The specific gravity of the organic solvent (S1) in this embodiment is greater than 1.0, preferably 1.05 or more, and more preferably 1.1 or more.

[0036] The organic solvent (S1) may be used alone or in combination of two or more kinds. The proportion of the organic solvent (S1) in the chemical solution is preferably 50% by mass or more, more preferably 75% by mass or more, and may be 100% by mass, based on the total mass of the chemical solution.

[0037] <Other organic solvents (S2)> The chemical solution in this embodiment may contain an organic solvent (S2) other than the organic solvent (S1) described above. Examples of other organic solvents (S2) 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, sulfone solvents, and nitrile solvents; and hydrocarbon solvents.

[0038] The organic solvent (S2) may be used alone or in combination of two or more kinds.

[0039] The chemical solution in this embodiment may consist of only the organic solvent (S1) or may be a mixed solvent of the organic solvent (S1) and the organic solvent (S2), but even in the case of a mixed solvent, the specific gravity is preferably greater than 1.0, more preferably 1.05 or greater, and even more preferably 1.1 or greater. That is, the chemical solution in this embodiment preferably has a specific gravity of greater than 1.0 as a whole, more preferably 1.05 or greater, and even more preferably 1.1 or greater.

[0040] The chemical solution in the chemical solution replacement step S102 preferably has the property of dissolving 0.5 to 40 g of water in 100 mL of the chemical solution at 25°C, more preferably has the property of dissolving 1 to 30 g of water in 100 mL of the chemical solution at 25°C, and even more preferably has the property of dissolving 2 to 20 g of water in 100 mL of the chemical solution at 25°C.

[0041] When the chemical has the above-mentioned dissolving properties, the substitution property for the rinse liquid with the chemical and the effect of suppressing pattern collapse are improved in a balanced manner.

[0042] The solubility characteristics of the chemical solution as described above may be adjusted by selecting an organic solvent (S1) that satisfies the above range, or by mixing the organic solvent (S1) and the organic solvent (S2) to satisfy the above range.

[0043] <Other ingredients> The chemical solution may contain other components in addition to the organic solvent (S1) and the organic solvent (S2) within the scope of the present invention, such as metal chelating agents (aminocarboxylic acid chelating agents, phosphonic acid chelating agents, acetylene alcohol, etc.), pH adjusters, surfactants, known organic solvents other than those mentioned above, etc.

[0044] [State change step S103] The state change step S103 is a step of raising the temperature of the substrate wetted with the chemical solution in the chemical solution replacement step S102 to a temperature equal to or higher than the critical temperature of the chemical solution, thereby bringing the chemical solution into a supercritical state. By bringing a chemical liquid to a temperature and pressure above its critical point, it can be put into a supercritical state. Here, the supercritical state refers to the state of a substance when it is placed under a temperature and pressure above its critical point, and a chemical liquid in the supercritical state has both the diffusibility of a gas and the solubility (high density) of a liquid. In the state change step S103, the chemical liquid is heated / pressurized to or above the critical point.

[0045] [Removal step S104] The removing step S104 is a step of removing the chemical liquid in the supercritical state caused by the state changing step S103 from the surface of the substrate. In the substrate processing method of this embodiment, the chemical liquid is removed by bringing it into a supercritical state, so that an interface between the liquid and the gas is not formed, and drying can be performed without surface tension acting on the pattern. Specific examples of the removal process S104 include tilting the substrate and causing the supercritical chemical liquid to flow, thereby removing the chemical liquid from the surface of the substrate, and reducing the pressure to vaporize the supercritical chemical liquid. The removing step S104 in this embodiment preferably includes an operation of tilting the substrate and causing the chemical liquid in the supercritical state to flow, thereby removing the chemical liquid from the surface of the substrate.

[0046] [Optional process] The substrate processing method of this embodiment may include an optional step other than the above-described rinsing step S101, chemical liquid substitution step S102, state changing step S103, and removal step S104. The optional step may include a cleaning step.

[0047] <Cleaning process> The cleaning step is a step of cleaning the surface of the substrate before the above-mentioned rinsing step S101. The cleaning method is not particularly limited, and examples of the method for cleaning a substrate include the well-known RCA cleaning method, in which 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 a hydrofluoric acid solution to remove the native oxide film on the surface of the substrate, and then immersed in an acidic solution (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.

[0048] The substrate processing method of this embodiment described above uses a chemical solution containing an organic solvent (S1) having a specific gravity greater than that of water, and processes the substrate by bringing the chemical solution into a supercritical state. Therefore, when the water-containing rinse solution is replaced with the chemical solution, the chemical solution penetrates below the rinse solution, effectively removing the rinse solution from the substrate. Therefore, the substrate processing method of this embodiment can remove even a very small amount of rinse solution remaining on the substrate, and is effective in suppressing pattern collapse. Furthermore, if a chemical liquid having a moderately low solubility in water is selected, it is less likely to absorb moisture from the atmosphere and less likely to involve external impurities, resulting in a better effect of suppressing pattern collapse. Furthermore, when the chemical solution does not contain an organic solvent containing fluorine atoms, costs and environmental impact can be further reduced.

[0049] Second Embodiment FIG. 2 shows a flow diagram of a substrate processing method according to the second embodiment. The substrate processing method of this embodiment includes a rinsing step S201 of rinsing the surface of the substrate with a rinse liquid containing water; a chemical liquid replacement step S202 of bringing a chemical liquid into contact with the surface of the rinsed substrate in a first chamber to replace the liquid adhering to the surface of the substrate from the rinse liquid with the chemical liquid; a transport step of transporting the substrate from the first chamber where the chemical liquid replacement step S202 has been performed to a second chamber; a state change step S204 of raising the temperature of the substrate wetted with the chemical liquid transported into the second chamber to a temperature equal to or higher than the critical temperature of the chemical liquid to bring the chemical liquid into a supercritical state; and a removal step S205 of removing the chemical liquid in the supercritical state from the surface of the substrate, wherein the chemical liquid contains the above-mentioned organic solvent (S1).

[0050] [Rinse process S201] The rinsing step S201 in this embodiment is the same as the above-described rinsing step S101.

[0051] [Chemical solution replacement process S202] The chemical liquid replacement step S202 in this embodiment is the same as the rinsing step S201 described above, except that in this embodiment, at least the chemical liquid replacement step S202 and the state change step S204 are performed in different chambers. The first chamber in which the chemical solution replacement step S202 is performed is not particularly limited, and may be, for example, a container made of stainless steel.

[0052] [Transportation process S203] The transfer step S203 is a step of transferring the substrate from the first chamber where the chemical liquid substitution step S202 is performed to the second chamber where the state change step S204 is performed. Specific examples of the method for transporting the substrate include a method in which the substrate is transported by transport rollers and a method in which the substrate is floated by air and transported. Even in the substrate processing method including the transport step S203 in which the chemical liquid is likely to absorb moisture from the atmosphere, the chemical liquid in this embodiment can remove even a small amount of rinse liquid in the subsequent removal step S205, and therefore has a good effect in suppressing pattern collapse.

[0053] [State change step S204] The state change step S204 is the same as the state change step S104 described above. The first chamber in which the state change step S204 is performed may be, for example, a high-pressure vessel made of stainless steel and having a predetermined pressure resistance.

[0054] [Removal step S205] The removal step S205 is the same as the removal step S105 described above.

[0055] The substrate processing method of the second embodiment may also include an optional step such as the cleaning step described above.

[0056] The substrate processing method of this embodiment described above uses a chemical solution containing the organic solvent (S1) described above, so even if it is a substrate processing method that includes the transport step S203, it can effectively remove the rinse liquid and has a good effect of suppressing pattern collapse. Furthermore, if a chemical liquid with a moderately low solubility in water is selected, it will be less likely to absorb moisture from the atmosphere during the transport step S203 and less likely to involve external impurities, resulting in a better effect of suppressing pattern collapse.

[0057] (medicinal solution) A second aspect of the present invention is a chemical solution used in a substrate processing method, the method comprising: a rinsing step of rinsing the surface of a substrate having a textured pattern formed thereon with a rinsing solution containing water; a chemical solution substitution step of bringing a chemical solution into contact with the surface of the rinsed substrate and substituting the rinsing solution for the liquid adhering to the surface of the substrate; a state change step of raising the temperature of the substrate wetted with the chemical solution to a temperature equal to or higher than the critical temperature of the chemical solution to bring the chemical solution into a supercritical state; and a removal step of removing the chemical solution in the supercritical state from the surface of the substrate. The chemical solution contains an organic solvent (S1) having a specific gravity greater than that of water (excluding organic solvents having fluorine atoms).

[0058] The chemical liquid of this embodiment may be the same as the chemical liquid described in the substrate processing method according to the first aspect of the present invention.

[0059] The chemical liquid of this embodiment is a chemical liquid that is useful for use in a supercritical drying method such as the substrate processing method according to the first aspect of the present invention described above.

[0060] Since the chemical solution of this embodiment contains the organic solvent (S1), when replacing a rinse solution containing water with the chemical solution, the chemical solution penetrates into the lower part of the rinse solution and can effectively remove the rinse solution from the substrate. Therefore, the chemical solution of this embodiment can remove even a very small amount of rinse solution remaining on the substrate, thereby improving the effect of suppressing pattern collapse. Furthermore, if the chemical solution has an appropriately low solubility in water, it is less likely to absorb moisture from the atmosphere and less likely to incorporate external impurities, thereby further improving the effect of suppressing pattern collapse. Furthermore, if the chemical solution does not contain an organic solvent containing fluorine atoms, the cost and the environmental load can be further reduced.

[0061] (Method of providing medicine) A third aspect of the present invention is a method for providing a chemical solution, which provides the chemical solution to a process line that performs the substrate processing method according to the first aspect of the present invention.

[0062] The chemical solution used here may be prepared by appropriately selecting from the materials described above (such as the organic solvent (S1)), and the timing of preparation of the chemical solution may be determined according to the size and operation speed of the process line.

[0063] Furthermore, the business entity that performs the substrate processing method and the business entity that performs the present providing method do not necessarily have to be the same. For example, the method of providing a chemical liquid in this embodiment is a method of providing a chemical liquid in which a business entity that performs the above-mentioned substrate processing method provides the chemical liquid to a process line that performs the substrate processing method, and another business entity provides the chemical liquid to the process line that performs the substrate processing method.

[0064] As described above, according to the present invention, it is possible to provide a substrate processing method and the like which is effective in suppressing pattern collapse when processing the surface of a substrate on which a concave-convex pattern is formed. [Example]

[0065] The present invention will be explained in more detail below with reference to the following reference examples, but the present invention is not limited to these examples.

[0066] In order to confirm the effect of replacing the rinse liquid adhering to the surface of the substrate with a chemical liquid, the following test was carried out. Silicon wafer test pieces were prepared and immersed in pure water at room temperature for 30 seconds. After that, the test pieces were removed from the pure water and, without drying, immersed in each of the chemical solutions listed in Table 1 at room temperature for 30 seconds. The appearance of water bubbles on the substrate surface during immersion was visually confirmed. The results are shown in Table 1. After immersing the test specimens in the chemical solutions for 30 seconds, the test specimens were visually inspected immediately after being removed from the solutions (before drying) to see if any water droplets or water bubbles remained on the test specimens. The results are shown in Table 1.

[0067] [Table 1]

[0068] As shown in Table 1, when the test piece was immersed in the chemical solutions of Reference Examples 1 and 2 consisting of the organic solvent (S1), water bubbles were observed on the substrate surface in all cases, unlike when the test piece was immersed in the chemical solution of Reference Comparative Example 1 consisting of an organic solvent other than the organic solvent (S1). Therefore, it can be confirmed that the chemical solutions of Reference Examples 1 and 2 consisting of the organic solvent (S1) have low solubility in water and are also considered to have low hygroscopicity. Furthermore, immediately after being pulled out of the chemical solutions of Reference Examples 1 and 2, the test pieces had no water droplets or water bubbles remaining on the surfaces of the test pieces, unlike the test pieces immediately after being pulled out of the chemical solutions of Reference Comparative Examples 2 to 4. Therefore, it was found that the chemical solutions of Reference Examples 1 and 2, which are made of an organic solvent (S1), are highly effective in replacing water on the surfaces of the test pieces with the chemical solution, and have good water removal properties from the surfaces of the test pieces.

[0069] From the above, it is presumed that when a chemical solution containing an organic solvent (S1) is used in a substrate processing method, the chemical solution has low moisture absorption but high moisture removal ability on the substrate, and therefore, a state change step of bringing the chemical solution into a supercritical state can be performed in a state where no moisture remains. Therefore, it is presumed that the substrate processing method of this embodiment can dry the substrate surface without leaving any moisture, and therefore has a good effect of suppressing pattern collapse.

[0070] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible within the scope of the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the appended claims.

Claims

1. A method for treating a substrate, the method comprising treating a surface of a substrate having a concave-convex pattern formed on the surface, the method comprising: a rinsing step of rinsing the surface of the substrate with a rinsing liquid containing water; a chemical liquid replacement step of bringing a chemical liquid into contact with the surface of the rinsed substrate to replace the liquid adhering to the surface of the substrate with the chemical liquid from the rinse liquid; a state change step of raising the temperature of the substrate wetted with the chemical solution to a critical temperature of the chemical solution or higher to bring the chemical solution into a supercritical state; a removing step of removing the chemical solution in a supercritical state from the surface of the substrate, The method for treating a substrate, wherein the chemical solution contains an organic solvent (S1) having a specific gravity greater than that of water (excluding compounds having halogen atoms).

2. 2. The method for treating a substrate according to claim 1, wherein the organic solvent (S1) has a specific gravity of 1.1 or more.

3. 3. The substrate processing method according to claim 1, wherein the specific gravity of the chemical solution is 1.1 or more.

4. 3. The substrate processing method according to claim 1, wherein the chemical solution has a property such that 0.5 to 40 g of water dissolves in 100 mL of the chemical solution at 25°C.

5. 3. The substrate processing method according to claim 1, wherein the chemical solution replacement step and the state change step are performed in different chambers, and a transport step of transporting the substrate from a first chamber in which the chemical solution replacement step is performed to a second chamber in which the state change step is performed is provided between the chemical solution replacement step and the state change step.

6. 3. The substrate processing method according to claim 1, wherein the removing step includes an operation of tilting the substrate and causing the chemical liquid in the supercritical state to flow, thereby removing the chemical liquid from the surface of the substrate.

7. a rinsing step of rinsing the surface of the substrate on which the concave-convex pattern has been formed with a rinse liquid containing water; a chemical liquid replacement step of bringing a chemical liquid into contact with the surface of the rinsed substrate to replace the liquid adhering to the surface of the substrate with the chemical liquid from the rinse liquid; a state change step of raising the temperature of the substrate wetted with the chemical solution to a critical temperature of the chemical solution or higher to bring the chemical solution into a supercritical state; a removing step of removing the chemical solution in a supercritical state from the surface of the substrate, A chemical solution containing an organic solvent (S1) having a specific gravity greater than that of water (excluding compounds having halogen atoms).

8. A method for providing a chemical solution, the method comprising: providing the chemical solution to a process line that performs the substrate processing method according to claim 1 .

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