Substrate processing method, chemical solution, and chemical solution supply method

Abstract

This invention relates to a substrate processing method for processing a substrate whose surface has an embossed pattern. The method includes: a rinsing step S101, in which the surface of the substrate is rinsed with a rinsing solution containing water; a solution replacement step S102, in which a solution is brought into contact with the surface of the rinsed substrate to replace the liquid adhering to the surface of the substrate with the solution; a state change step S103, in which the substrate wetted by the solution is heated to a temperature above the critical temperature of the solution to make the solution supercritical; and a removal step S104, in which the supercritical solution is removed from the surface of the substrate. The solution contains an organic solvent (S1) with a specific gravity greater than that of water (except for organic solvents containing fluorine atoms).

Description

[Technical Field]

[0001] This invention relates to a method for processing a substrate, a chemical solution, and a method for providing the chemical solution. This application is based on US63 / 250,239, filed in the United States on September 30, 2021, and claims priority thereto, the contents of which are incorporated herein by reference. [Previous Technology]

[0002] In recent years, due to advancements in lithography technology, the miniaturization of semiconductor substrate patterns has progressed rapidly in the manufacturing of semiconductor components and liquid crystal display components. As the patterns on semiconductor substrates become more miniaturized, the aspect ratio of the patterns on semiconductor substrates tends to increase.

[0003] On the other hand, in the semiconductor manufacturing process, the manufacturing yield decreases due to the contamination of particles and the like. Therefore, in order to remove particles and the like adhering to the substrate, the substrate is cleaned using a rinsing solution. After the patterned substrate is cleaned with the rinsing solution, the rinsing solution is removed by drying the substrate. At this time, the pattern on the substrate surface may collapse due to the capillary force of the rinsing solution remaining in the pattern.

[0004] As a method to solve the problem of pattern collapse, a supercritical drying method using a supercritical fluid with almost zero surface tension has been proposed. By means of supercritical drying, since no gas-liquid interface is formed, the surface of the substrate can be dried without the action of capillary force.

[0005] For example, Patent Document 1 discloses a method for processing a semiconductor substrate, characterized in that, in a method of washing the surface of the semiconductor substrate with an aqueous cleaning solution and then replacing the aqueous cleaning solution adhering to the substrate surface with a supercritical fluid for drying, the fluid used is a solvent containing fluorinated alcohols with a content of Fe, Ni, Cr, Al, Zn, Cu, Mg, Li, K, Na, and Ca of 500 ppb or less by mass and containing fluorinated alcohols with 2 to 6 carbon atoms. [Prior Art Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2017-92285 [Summary of the Invention]

[0007] [The problem the invention aims to solve]

[0008] The semiconductor substrate processing method described in Patent Document 1 uses a fluorinated alcohol with 2 to 6 carbon atoms as a solvent. The fluorinated alcohol is not very versatile as a solvent, lacks easy availability, and due to its high global warming potential, there are still issues in its mass production application.

[0009] Additionally, isopropyl alcohol (IPA) is generally used as a supercritical fluid. However, IPA is prone to absorbing moisture from the atmosphere and easily mixed with external impurities, thus raising concerns that this could be the starting point for pattern collapse.

[0010] This invention was made in view of the above-mentioned circumstances, and the objective is to provide: a method for processing a substrate with good pattern collapse suppression effect when processing the surface of a substrate with an embossed pattern, a solution for the substrate processing method, and a method for providing the solution. [Means for solving the problem]

[0011] To solve the above-mentioned problems, the present invention adopts the following configuration. That is, the first aspect of the present invention is a substrate processing method, which is a substrate processing method for processing the aforementioned surface of a substrate on which an uneven pattern is formed, comprising: a rinsing step, rinsing the surface of the aforementioned substrate with a rinsing solution containing water; a solution replacement step, contacting the aforementioned rinsed substrate surface with a solution to replace the liquid adhering to the aforementioned substrate surface from the aforementioned rinsing solution with the aforementioned solution; a state change step, heating the aforementioned substrate wetted by the aforementioned solution to above the critical temperature of the aforementioned solution, so that the aforementioned solution becomes supercritical; and a removal step, removing the aforementioned supercritical solution from the surface of the aforementioned substrate, wherein the aforementioned solution contains an organic solvent with a specific gravity greater than that of water (S1) (however, organic solvents having fluorine atoms are excluded).

[0012] The second aspect of the present invention is a liquid solution, which is a method for processing a substrate. The substrate processing method includes: a rinsing step, rinsing the surface of a substrate with an embossed pattern formed thereon with a rinsing solution containing water; a liquid replacement step, bringing the liquid solution into contact with the surface of the rinsed substrate, replacing the liquid adhering to the surface of the substrate with the liquid solution; a state change step, heating the substrate wetted by the liquid solution to above the critical temperature of the liquid solution, so that the liquid solution becomes supercritical; and a removal step, removing the supercritical liquid solution from the surface of the substrate, wherein the liquid solution contains an organic solvent with a specific gravity greater than that of water (S1) (except for organic solvents containing fluorine atoms).

[0013] The third aspect of the present invention is a method for providing a pharmaceutical solution, which involves supplying the aforementioned pharmaceutical solution to a production line that implements the substrate processing method of the first aspect of the present invention. [Effects of the Invention]

[0014] According to the present invention, a method for processing a substrate in which pattern collapse suppression is good when processing the surface of a substrate with an embossed pattern, a solution for the method of processing the substrate, and a method for providing the solution are provided.

Implementation Method

[0016] (Substrate processing method)

[0017] The first embodiment of the present invention is a substrate processing method, which is a substrate processing method for processing the aforementioned surface of a substrate on which an uneven pattern is formed, comprising: a rinsing step, rinsing the surface of the aforementioned substrate with a rinsing solution containing water; a solution replacement step, contacting the aforementioned rinsed substrate surface with a solution to replace the liquid adhering to the aforementioned substrate surface from the aforementioned rinsing solution with the aforementioned solution; a state change step, heating the aforementioned substrate wetted by the aforementioned solution to above the critical temperature of the aforementioned solution, so that the aforementioned solution becomes supercritical; and a removal step, removing the aforementioned supercritical solution from the surface of the aforementioned substrate, wherein the aforementioned solution contains an organic solvent with a specific gravity greater than that of water (S1) (except for organic solvents containing fluorine atoms).

[0018] The substrate is not particularly limited and can be any known substrate, such as silicon (Si) substrate, silicon nitride (SiN) substrate, silicon oxide (Ox) substrate, silicon carbide (SiC) substrate, tungsten (W) substrate, tungsten carbide (WC) substrate, cobalt (Co) substrate, titanium nitride (TiN) substrate, tantalum nitride (TaN) substrate, germanium (Ge) substrate, silicon-germanium (SiGe) substrate, aluminum (Al) substrate, nickel (Ni) substrate, titanium (Ti) substrate, ruthenium (Ru) substrate, copper (Cu) substrate, etc. Taking silicon (Si) substrate as an example, it can be a silicon oxide film with a natural oxide film, thermal oxide film, or vapor-phase synthesis film (CVD film, etc.) formed on its surface, or it can be a silicon oxide film with a pattern formed on the aforementioned silicon oxide film.

[0019] "Surface" refers not only to the surface of the substrate itself, but also to the surface of inorganic patterns disposed on the substrate and the surface of unpatterned inorganic layers.

[0020] An inorganic pattern disposed on a substrate can be exemplified by forming an etching mask on the surface of an inorganic layer existing on the substrate using a photoresist method, and then forming the inorganic pattern by etching. In addition to the substrate itself, the inorganic layer can also be a layer made of oxides of elements constituting the substrate, or a layer formed on the surface of the substrate made of inorganic materials such as silicon nitride, titanium nitride, or tungsten. There is no particular limitation on such an inorganic layer; an inorganic layer formed during the manufacturing process of a semiconductor device can be exemplified.

[0021] The shape of the aforementioned pattern is not particularly limited, and may be a pattern shape generally formed in the semiconductor manufacturing process. The pattern shape may be a line pattern, a hole pattern, or a pattern containing a plurality of pillars. The pattern shape is preferably a pattern containing a plurality of pillars. The shape of the pillars is not particularly limited, and may include cylindrical shapes, polygonal prism shapes (quadrilateral prism shapes, etc.).

[0022] <First Embodiment> Figure 1 shows a flowchart of a substrate processing method according to the first embodiment. The substrate processing method of this embodiment includes: a rinsing step S101, rinsing the surface of the substrate with a rinsing solution containing water; a solution replacement step S102, contacting the solution with the rinsed surface of the substrate to replace the liquid adhering to the substrate surface with the solution; a state change step S103, heating the substrate wetted by the solution to above the critical temperature of the solution to make the solution supercritical; and a removal step S104, removing the supercritical solution from the surface of the substrate.

[0023] [Rinsing Step S101] The rinsing step S101 is a step of rinsing the surface of the substrate with a rinsing solution containing water. The rinsing method is not particularly limited, and methods generally used in semiconductor manufacturing processes for cleaning the substrate can be used. Examples of such methods include spin coating, immersion coating, spray coating, and liquid coating, which will be described later.

[0024] Spin coating is a method of using a spin coater or similar machine to rotate a substrate and then dripping or spraying a rinsing liquid onto the rotating substrate. Immersion coating is a method of immersing a substrate in a rinsing liquid. Spraying coating is a method of conveying a substrate in a predetermined direction and spraying rinsing liquid into that space. Liquid-coating coating is a method of using surface tension to deposit rinsing liquid onto a substrate and then allowing it to remain stationary for a certain period of time.

[0025] In the above, the rinsing step S101 is preferably a spin coating method. Examples of the rotation speed are 100 rpm to 5000 rpm.

[0026] ･The rinsing solution in the rinsing step S101 includes water. Pure water, deionized water, ion-exchanged water, etc., can be used as water. In this embodiment, the rinsing solution may contain organic solvents in addition to water.

[0027] As organic solvents, examples include hydrocarbons, esters, ethers, ketones, halogen-containing solvents, argon-containing solvents, alcohols, derivatives of polyols, and nitrogen-containing compound solvents.

[0028] The rinsing solution may further contain known additives. Examples of known additives include fluorinated surfactants or polysiloxane surfactants.

[0029] Specific examples of fluorinated surfactants include BM-1000, BM-1100 (both manufactured by BM Chemie), Megafac F142D, Megafac F172, Megafac F173, Megafac F183 (all manufactured by DIC), Fluorad FC-135, Fluorad FC-170C, Fluorad FC-430, Fluorad FC-431 (all manufactured by Sumitomo 3M), Surflon S-112, Surflon S-113, Surflon S-131, Surflon S-141, and Surflon S-15. Commercially available fluorinated surfactants such as S-145 (all manufactured by Asahi Glass), SH-28PA, SH-190, SH-193, SZ-6032, and SF-8428 (all manufactured by Toray Polysiloxane Co., Ltd.).

[0030] In specific examples, unmodified polysiloxane surfactants, polyether-modified polysiloxane surfactants, polyester-modified polysiloxane surfactants, alkyl-modified polysiloxane surfactants, aralkyl-modified polysiloxane surfactants, and reactive polysiloxane surfactants are preferred as polysiloxane surfactants. Commercially available polysiloxane surfactants can also be used. Specific examples of commercially available polysiloxane surfactants include Paintad M (manufactured by Toray Industries and Dow Corning), Topica K1000, Topica K2000, Topica K5000 (all manufactured by Takachiho Industries), XL-121 (polyether-modified polysiloxane surfactant, manufactured by Clariant), and BYK-310 (polyester-modified polysiloxane surfactant, manufactured by BYK).

[0031] [Drug replacement step S102] Drug replacement step S102 is a step of contacting the drug solution with the surface of the substrate that has been rinsed by the above-mentioned rinsing step S101, and replacing the liquid adhering to the surface of the substrate with the drug solution.

[0032] In the substrate processing method of this embodiment, at least the liquid replacement step S102 and the state change step S103 described later are performed in the same chamber. This chamber is, for example, a high-pressure container made of stainless steel to ensure predetermined pressure resistance.

[0033] The method of bringing the liquid medicine into contact with the surface of the substrate is not particularly limited. For example, the above-mentioned spin coating method, immersion method, spraying method, and liquid covering method can be listed.

[0034] <Drug Solution> The drug solution in the drug solution replacement step S102 contains an organic solvent (S1) with a specific gravity greater than that of water. However, the organic solvent (S1) is excluded from organic solvents containing fluorine atoms. From the viewpoint of reducing costs and environmental impact, the drug solution in this embodiment preferably does not contain organic solvents containing fluorine atoms.

[0035] ≪Organic Solvent (S1)≫ The organic solvent (S1) in this embodiment is not particularly limited to any organic solvent that does not have fluorine atoms and has a specific gravity greater than that of water. It is preferably a polar solvent such as a carbonate solvent or a lactone solvent. In this specification, "specific gravity" is a value calculated using water at 4°C as a standard substance.

[0036] As the organic solvent (S1) in this embodiment, suitable examples include propyl carbonate (propyl carbonate, specific gravity: 1.2047, solubility: 29.3), dimethyl carbonate (dimethyl carbonate, specific gravity: 1.0636, solubility: 8.5), ethyl carbonate (ethyl carbonate, specific gravity: 1.3214, solubility: 29.3), diethyl carbonate (diethyl carbonate, specific gravity: 1.069, solubility: 1.8), and butyl carbonate (butyl carbonate, specific gravity: 1.2047, solubility: 29.3). The following organic solvents are listed: 1.107 (specific gravity: 13.5, solubility: 13.5), furfuryl alcohol (specific gravity: 1.1296, solubility: 7.7), tetrahydrofurfuryl alcohol (specific gravity: 1.0544, solubility: 16.9), dihydro-L-glucanone (Cyrene, 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). Furthermore, the solubility of each organic solvent (S1) is expressed as the solubility (g / 100mL) of water dissolved relative to 100mL of each organic solvent (S1) at 25°C.

[0037] 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.

[0038] The organic solvent (S1) may be used alone or in combination of two or more. The proportion of the organic solvent (S1) in the solution is relative to the total mass of the solution, preferably 50% by mass or more, more preferably 75% by mass or more, and may also be 100% by mass.

[0039] ≪Other Organic Solvents (S2)≫ The pharmaceutical solution in this embodiment may also contain other organic solvents (S2) besides the aforementioned organic solvent (S1). Examples of other organic solvents (S2) include protic polar solvents such as glycol solvents, glycol ether solvents, and alcohol solvents; non-protic polar solvents such as ester solvents, amide solvents, sulfide solvents, sulfide solvents, and nitrile solvents; and hydrocarbon solvents.

[0040] The organic solvent (S2) can be used alone or in combination of two or more.

[0041] The pharmaceutical solution in this embodiment may be composed solely of organic solvent (S1), or it may be a mixture of organic solvent (S1) and organic solvent (S2). However, even in the case of a mixture of solvents, the specific gravity is preferably greater than 1.0, more preferably greater than 1.05, and even more preferably greater than 1.1. That is, the specific gravity of the pharmaceutical solution system in this embodiment as a whole is preferably greater than 1.0, more preferably greater than 1.05, and even more preferably greater than 1.1.

[0042] In the drug solution replacement step S102, the drug solution preferably has the property of dissolving 0.5 to 40 g of water per 100 mL of drug solution at 25°C, more preferably has the property of dissolving 1 to 30 g of water per 100 mL of drug solution at 25°C, and even more preferably has the property of dissolving 2 to 20 g of water per 100 mL of drug solution at 25°C.

[0043] Because the solution has the solubility properties described above, it can evenly improve the displacement from the rinsing solution to the solution and the pattern collapse suppression effect.

[0044] As described above, the solubility characteristics of the drug solution can be adjusted by selecting an organic solvent (S1) that meets the above range, or by mixing organic solvent (S1) and organic solvent (S2) to meet the above range.

[0045] ≪Other Ingredients≫ Without impairing the effects of the present invention, the solution may contain ingredients other than organic solvent (S1) and organic solvent (S2). Examples of other ingredients include metal chelating agents (aminocarboxylic acid chelating agents, phosphonic acid chelating agents, ethynyl alcohol, etc.), pH adjusters, surfactants, and known organic solvents other than the solvents mentioned above.

[0046] [State Change Step S103] State change step S103 involves heating the substrate, which has been wetted by the drug solution in the above-mentioned drug solution replacement step S102, to above the critical temperature of the drug solution, thereby making the drug solution into a supercritical state. By setting the temperature and pressure above the critical point, the drug solution can be made into a supercritical state. Here, supercritical state refers to the state of a substance at a temperature and pressure above the critical point. A drug solution in a supercritical state possesses both the diffusivity of a gas and the solubility (high density) of a liquid. As state change step S103, the above-mentioned drug solution is heated / pressurized above the critical point.

[0047] [Removal Step S104] Removal step S104 is a step of removing the supercritical state of the liquid substance obtained through the state change step S103 from the surface of the substrate. The substrate processing method of this embodiment removes the liquid substance by making it supercritical, thus preventing the formation of a liquid-gas interface, and allowing drying to be performed without surface tension acting on the pattern. Specifically, removal step S104 can include operations such as tilting the substrate to allow the supercritical state liquid substance to flow and remove it from the surface of the substrate, or reducing the pressure to vaporize the supercritical state liquid substance. Preferably, removal step S104 in this embodiment includes operations such as tilting the substrate to allow the supercritical state liquid substance to flow and remove it from the surface of the substrate.

[0048] [Any Step] The substrate processing method of this embodiment may include any step other than the above-described rinsing step S101, solution replacement step S102, state change step S103, and removal step S104. A washing step is an example of such an arbitrary step.

[0049] <Cleaning Step> The cleaning step is a pre-cleaning step of the substrate surface before the rinsing step S101 described above. The cleaning method is not particularly limited; for example, the well-known RCA cleaning method can be cited as a substrate cleaning method. In this RCA cleaning method, the substrate is first immersed in a solution of hydrogen peroxide and ammonium hydroxide (SC-1) to remove microparticles and organic matter from the substrate. Next, the substrate is immersed in an aqueous hydrofluoric acid solution to remove the natural oxide film on the substrate surface. Afterward, the substrate is immersed in an acidic solution of hydrogen peroxide and dilute hydrochloric acid (SC-2) to remove alkali ions or metallic impurities that are insoluble in the SC-1 solution.

[0050] The substrate processing method of this embodiment described above uses a solution containing an organic solvent (S1) with a specific gravity greater than water, and the solution is brought to a supercritical state for substrate processing. Therefore, when the water-containing rinsing solution is replaced by the solution, the solution penetrates into the lower part of the rinsing solution, effectively removing the rinsing solution from the substrate. Thus, the substrate processing method of this embodiment can remove even trace amounts of rinsing solution remaining on the substrate, resulting in excellent pattern collapse suppression. Furthermore, when a solution with moderately low solubility in water is selected, it is less likely to absorb moisture from the atmosphere and less likely to mix with external impurities, thus further improving the pattern collapse suppression effect. Moreover, if the solution does not contain organic solvents containing fluorine atoms, cost and environmental impact can be further reduced.

[0051] <Second Embodiment> Figure 2 shows a flowchart of the substrate processing method according to the second embodiment. The substrate processing method of this embodiment includes: a rinsing step S201, rinsing the surface of the substrate with a rinsing solution containing water; a solution replacement step S202, contacting the surface of the rinsed substrate with a solution in a first chamber to replace the liquid adhering to the surface of the substrate with the solution; a transport step, transporting the substrate from the first chamber where the solution replacement step S202 is performed to a second chamber; a state change step S204, heating the substrate wetted by the solution in the second chamber to above the critical temperature of the solution, making the solution supercritical; and a removal step S205, removing the supercritical solution from the surface of the substrate, wherein the solution contains the organic solvent (S1) of the substrate.

[0052] [Rinsing Step S201] The rinsing step S201 in this embodiment is the same as the rinsing step S101 described above.

[0053] [Drug Replacement Step S202] The drug replacement step S202 in this embodiment is the same as the rinsing step S201 described above. However, in this embodiment, at least the drug replacement step S202 and the state change step S204 are performed in different chambers. The first chamber for performing the drug replacement step S202 is not particularly limited; for example, a container made of stainless steel can be used.

[0054] [Transfer Step S203] The transfer step S203 is a step in which the substrate is transferred from the first chamber where the solution replacement step S202 is performed to the second chamber where the state change step S204 is performed. Specifically, methods for transferring the substrate include transferring it using transfer rollers or using air to levitate the substrate for transfer. Even in the substrate treatment method of the transfer step S203, where the solution easily absorbs moisture from the atmosphere, a small amount of rinsing solution can be removed through the subsequent removal step S205, thus achieving a good pattern collapse suppression effect.

[0055] [State Change Step S204] State change step S204 is the same as state change step S104 described above. As the first chamber for performing state change step S204, a high-pressure vessel made of stainless steel that can ensure a predetermined pressure resistance can be cited as an example.

[0056] [Removal step S205] Removal step S205 is the same as removal step S105 described above.

[0057] The substrate processing method of the second embodiment may also include any step such as the cleaning step described above.

[0058] The substrate processing method of this embodiment described above uses a solution containing the aforementioned organic solvent (S1). Therefore, even for substrates with a transport step S203, the rinsing liquid can be effectively removed, resulting in good pattern collapse suppression. Furthermore, when a solution with moderately low solubility in water is selected, it is less likely to absorb moisture from the atmosphere during the transport step S203, and it is less likely to introduce external impurities, thus further enhancing the pattern collapse suppression effect.

[0059] (Medicinal Solution) The second embodiment of the present invention is a medicinal solution, which is a method for processing a substrate. The substrate processing method includes: a rinsing step, rinsing the surface of a substrate with an embossed pattern formed thereon with a rinsing solution containing water; a medicinal solution replacement step, contacting the aforementioned rinsed substrate surface with the medicinal solution to replace the liquid adhering to the aforementioned substrate surface from the aforementioned rinsing solution with the aforementioned medicinal solution; a state change step, heating the aforementioned substrate wetted by the aforementioned medicinal solution to above the critical temperature of the aforementioned medicinal solution, so that the aforementioned medicinal solution becomes supercritical; and a removal step, removing the aforementioned supercritical state medicinal solution from the surface of the aforementioned substrate, wherein the aforementioned medicinal solution contains an organic solvent with a specific gravity greater than that of water (S1) (however, organic solvents having fluorine atoms are excluded).

[0060] The liquid in this embodiment may be the same as the liquid described in the substrate processing method of the first embodiment of the present invention.

[0061] The solution of this embodiment is a useful solution that can be used in the supercritical drying method of the substrate processing method of the first embodiment of the present invention as described above.

[0062] Since the solution of this embodiment contains the aforementioned organic solvent (S1), when the rinsing solution containing water is replaced by the solution, the solution penetrates into the lower part of the rinsing solution, effectively removing the rinsing solution on the substrate. Therefore, with the solution of this embodiment, even trace amounts of rinsing solution remaining on the substrate can be removed, improving the pattern collapse suppression effect. Furthermore, when the solubility of the solution in water is moderately low, it is difficult to absorb moisture from the atmosphere and difficult for external impurities to mix in, thus further improving the pattern collapse suppression effect. Moreover, since the solution does not contain organic solvents containing fluorine atoms, it can further reduce costs and environmental impact.

[0063] (Method for providing the drug solution) The third aspect of the present invention is a method for providing the drug solution, which is to provide the aforementioned drug solution to a production line of a substrate processing method for implementing the first aspect of the present invention.

[0064] The medicine solution here can be prepared by selecting appropriate materials (organic solvent (S1) etc.) and the timing of preparation of the medicine solution can be planned according to the size and operating speed of the production line.

[0065] Furthermore, the actuator for implementing the substrate processing method does not necessarily need to be the same as the actuator for implementing the method provided herein. For example, in the method for providing the liquid medicine in this embodiment, the liquid medicine is provided by other actuators, namely the production line for implementing the substrate processing method.

[0066] As explained above, according to the present invention, a method for processing a substrate that provides good pattern collapse suppression when processing a substrate surface with an uneven pattern is provided. [Example]

[0067] Hereinafter, the present invention will be described in more detail by way of reference, but the present invention is not limited to these examples.

[0068] To confirm the effectiveness of replacing the rinsing solution adhering to the substrate surface with the chemical solution, the following tests were conducted. Silicon wafer test pieces were prepared and immersed in pure water for 30 seconds at room temperature. Afterwards, the test pieces, without drying, were immersed in the chemical solutions listed in Table 1 for 30 seconds at room temperature. The presence of water bubbles on the substrate surface during immersion was visually confirmed. The results are shown in Table 1. Furthermore, after immersing the test pieces in the chemical solutions for 30 seconds, the presence of water droplets or water bubbles was visually confirmed immediately after being pulled out of each chemical solution (before drying). The results are shown in Table 1.

[0069]

[0070] As shown in Table 1, the cases where the test pieces were immersed in the solutions of Reference Examples 1 and 2 made of organic solvent (S1) differed from the cases where the test pieces were immersed in the solution of Comparative Reference Example 1 made of an organic solvent other than organic solvent (S1). In both cases, water bubbles were observed on the substrate surface. Therefore, it can be confirmed that the solutions of Reference Examples 1 and 2 made of organic solvent (S1) have low solubility in water and can be considered to have low hygroscopicity. Furthermore, the test pieces immediately after being pulled out of the solutions of Reference Examples 1 and 2 differed from the test pieces immediately after being pulled out of the solutions of Comparative Reference Examples 2 to 4; no water droplets or water bubbles remained on the surface of the test pieces. Therefore, it can be seen that the solutions of Reference Examples 1 and 2 made of organic solvent (S1) are highly effective at replacing the water on the surface of the test pieces with the solution, and the water removal performance on the surface of the test pieces is good.

[0071] As described above, in the substrate processing method, when a solution containing an organic solvent (S1) is used, the solution has low hygroscopicity and high moisture removal capability on the substrate. Therefore, it can be assumed that the state change step of making the solution into a supercritical state can be performed without leaving any moisture. Therefore, the substrate processing method of this embodiment can dry the substrate surface without leaving any moisture, so it can be assumed that the pattern collapse suppression effect is good.

[0072] The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications are possible without departing from the spirit of the present invention. The present invention is not limited by the foregoing description, but only by the appended claims. [Simplified Explanation of the Diagram]

[0015] [Figure 1] Flowchart of the substrate processing method in the first embodiment. [Figure 2] Flowchart of the substrate processing method in the second embodiment.

Claims

1. A method for processing a substrate, comprising processing the surface of a substrate having an embossed pattern formed thereon, comprising: a rinsing step of rinsing the surface of the substrate with a rinsing solution containing water; a solution replacement step of contacting a solution with the rinsed surface of the substrate to replace the liquid adhering to the surface of the substrate with the solution; a state change step of heating the substrate wetted by the solution to above the critical temperature of the solution to make the solution supercritical; and a removal step of removing the supercritical solution from the surface of the substrate, wherein the solution contains an organic solvent (S1) with a specific gravity greater than that of water, except for organic solvents having fluorine atoms, and the organic solvent (S1) includes one or more solvents selected from the group consisting of carbonate solvents and lactone solvents.

2. The substrate processing method as described in claim 1, wherein, The specific gravity of the aforementioned organic solvent (S1) is 1.1 or higher.

3. The substrate processing method as described in claim 1 or 2, wherein, The specific gravity of the aforementioned medicinal solution is 1.1 or higher.

4. The substrate processing method as described in claim 1 or 2, wherein, The aforementioned drug solution has the property of dissolving 0.5 to 40 g of water per 100 mL of the aforementioned drug solution at 25°C.

5. The substrate processing method as described in claim 1 or 2, wherein, The aforementioned drug replacement step and the aforementioned state change step are performed in different chambers. Furthermore, between the aforementioned drug replacement step and the aforementioned state change step, there is a transfer step that moves the aforementioned substrate from the first chamber where the aforementioned drug replacement step is performed to the second chamber where the aforementioned state change step is performed.

6. The method for processing the substrate as described in claim 1 or 2, wherein, The aforementioned removal step includes removing the aforementioned drug solution from the surface of the aforementioned substrate by tilting the aforementioned substrate to allow the aforementioned supercritical state drug solution to flow.

7. A method for providing a solution, wherein the solution is provided to a process line that performs a substrate processing method as described in any one of claims 1 to 6.

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