Substrate treatment method, substrate treatment device, and substrate treatment solution

Abstract

Provided are a substrate treatment method, a substrate treatment device, and a substrate treatment solution that make it possible to perform sublimation drying while further preventing collapsing of a pattern formed on the surface of a substrate. A substrate treatment method according to the present invention is for treating a pattern formation surface of a substrate W, and comprises: a supply step for supplying a substrate treatment solution containing a sublimable substance and a solvent to the pattern formation surface; a solidification step for evaporating the solvent in a liquid film of the substrate treatment solution supplied to the pattern formation surface in the supply step and precipitating the sublimable substance to form a solidified film containing the sublimable substance; and a sublimation step for sublimating the solidified film to remove the solidified film. The sublimable substance contains at least one of 2-(1-adamantyl)-4-methylphenol, 3,5-dimethyl-1-adamantanol, and hexahydrophthalimide.

Description

Substrate Processing Method, Substrate Processing Apparatus, and Substrate Processing Liquid

[0001] The present invention relates to a substrate processing method, a substrate processing apparatus, and a substrate processing liquid for removing a liquid attached to various substrates such as a semiconductor substrate, a glass substrate for a photomask, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for a FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, and a substrate for a magneto-optical disk (hereinafter referred to as "substrate").

[0002] In recent years, with the miniaturization of patterns formed on substrates such as semiconductor substrates, the aspect ratio (the ratio of the height to the width of the pattern convex portion) of the convex portions of the pattern having irregularities has been increasing. Therefore, during the drying process, the surface tension acting on the interface between the liquid such as the cleaning liquid and the rinse liquid that has entered the concave portion of the pattern and the gas in contact with the liquid pulls adjacent convex portions in the pattern together and causes them to collapse, which is a so-called pattern collapse problem.

[0003] As a drying technique for preventing such pattern collapse, for example, Patent Document 1 discloses a substrate drying method for removing a liquid on a substrate having a pattern of irregularities on its surface and drying the substrate. According to this substrate drying method, a solution of a sublimable substance is supplied to the substrate, the solution is filled in the concave portion of the pattern, the solvent in the solution is dried, the concave portion of the pattern is filled with the sublimable substance in a solid state, and the substrate is heated to a temperature higher than the sublimation temperature of the sublimable substance to remove the sublimable substance from the substrate. Thereby, in Patent Document 1, it is said that the stress that tries to collapse the convex portion of the pattern that may be caused by the surface tension of the liquid on the substrate is suppressed from acting on the convex portion of the pattern, and pattern collapse can be prevented.

[0004] Further, Patent Document 2 discloses a substrate processing method using a substrate processing liquid containing at least one sublimable substance of camphor and naphthalene and a solvent such as isopropyl alcohol when performing sublimation drying on the surface of a substrate on which a fine pattern is formed. According to this substrate processing method, it is said that pattern collapse in a partial or local region can be better suppressed than in a conventional substrate processing liquid.

[0005] Japanese Patent Publication No. 2012-243869 Japanese Patent Publication No. 2020-4948

[0006] However, even when using the sublimation drying method described above, there is a problem in that the collapse of the pattern cannot be adequately prevented if the mechanical strength of the pattern is extremely low.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a substrate processing method, a substrate processing apparatus, and a substrate processing liquid that can perform sublimation drying while further preventing the collapse of patterns formed on the surface of the substrate.

[0008] The substrate processing method according to the present invention is a substrate processing method for processing a pattern-forming surface of a substrate in order to solve the above problems, comprising: a supply step of supplying a substrate processing liquid containing a sublimable substance and a solvent to the pattern-forming surface; a solidification step of evaporating the solvent in the liquid film of the substrate processing liquid supplied to the pattern-forming surface in the supply step to precipitate the sublimable substance and form a solidified film containing the sublimable substance; and a sublimation step of sublimating the solidified film and removing the solidified film, wherein the sublimable substance contains at least one of 2-(1-adamantyl)-4-methylphenol, 3,5-dimethyl-1-adamantanol, and hexahydrophthalimide.

[0009] According to the substrate processing method of the above configuration, for example, when a liquid is present on the pattern-forming surface of a substrate, the liquid can be removed while preventing the collapse of the pattern by the principle of sublimation drying. Specifically, after supplying the substrate processing liquid to the pattern-forming surface in the supply step, the solvent in the liquid film of the substrate processing liquid is evaporated in the solidification step to precipitate a sublimable substance and form a solidified film. Subsequently, the solidified film is removed by sublimation. In the above configuration, the substrate processing liquid contains at least one of 2-(1-adamantyl)-4-methylphenol, 3,5-dimethyl-1-adamantanol, and hexahydrophthalimide (hereinafter sometimes referred to as "2-(1-adamantyl)-4-methylphenol, etc."). As a result, compared to substrate processing liquids using conventional sublimable substances, sublimation drying can be performed while effectively suppressing the collapse of the pattern, even in the case of patterns with extremely low mechanical strength.

[0010] In the above configuration, the process further includes a thinning step in which the substrate is rotated at a first rotational speed around a rotation axis parallel to the perpendicular direction of the pattern forming surface, thereby thinning the liquid film of the substrate processing liquid supplied in the supply step on the pattern forming surface, and the solidification step preferably involves rotating the substrate around the rotation axis at a second rotational speed faster than the first rotational speed to evaporate the solvent in the liquid film.

[0011] Furthermore, in the above configuration, the solidification step may be performed by supplying an inert gas to the pattern-forming surface after the precipitation of the sublimable substance to promote the formation of the solidified film.

[0012] Furthermore, in the above configuration, if the sublimable substance is 3,5-dimethyl-1-adamantanol, the sublimation step is preferably carried out by supplying an inert gas to the pattern-forming surface while the substrate is rotated around a rotation axis parallel to the perpendicular direction of the pattern-forming surface, thereby sublimating the solidified film.

[0013] Furthermore, if the sublimable substance is at least one of 2-(1-adamantyl)-4-methylphenol and hexahydrophthalimide, the sublimation step is preferably performed by heating the solidified film to cause sublimation.

[0014] Furthermore, in the above configuration, it is preferable to use a solvent that has a higher vapor pressure at room temperature than the sublimable substance. This facilitates the precipitation of 2-(1-adamantyl)-4-methylphenol and the like by evaporation of the solvent, and enables the formation of a solidified film containing the sublimable substance.

[0015] Furthermore, in the above configuration, it is preferable that the solvent is at least one of methanol, butanol, isopropyl alcohol, and acetone.

[0016] Furthermore, the substrate processing apparatus according to the present invention, in order to solve the above problems, is a substrate processing apparatus for processing the pattern-forming surface of a substrate, comprising: a substrate holding unit that holds the substrate so as to be rotatable about a rotation axis parallel to the perpendicular direction of the pattern-forming surface; a supply unit that supplies a substrate processing liquid containing a sublimable substance and a solvent to the pattern-forming surface of the substrate held by the substrate holding unit; and a sublimation unit that sublimates the solidified film containing the sublimable substance and removes the solidified film, wherein the substrate holding unit evaporates the solvent in the liquid film of the substrate processing liquid supplied to the pattern-forming surface by the supply unit by rotating the substrate about the rotation axis to precipitate the sublimable substance and form a solidified film containing the sublimable substance, and the sublimable substance in the substrate processing liquid supplied by the supply unit contains at least one of 2-(1-adamantyl)-4-methylphenol, 3,5-dimethyl-1-adamantanol, and hexahydrophthalimide.

[0017] According to the substrate processing apparatus with the above configuration, for example, when a liquid is present on the pattern-forming surface of a substrate, the liquid can be removed while preventing the collapse of the pattern by the principle of sublimation drying. Specifically, the substrate holding unit holds the substrate so that it can rotate around a rotation axis parallel to the direction perpendicular to its pattern-forming surface. The supply unit supplies the substrate processing liquid to the pattern-forming surface of the substrate held by the substrate holding unit. The substrate holding unit evaporates the solvent from the liquid film of the substrate processing liquid by rotating the substrate. This allows a sublimable substance to precipitate and form a solidified film. Subsequently, the sublimation unit sublimes the solidified film containing the sublimable substance, thereby removing the solidified film. In the above configuration, the sublimable substance contained in the substrate processing liquid includes 2-(1-adamantyl)-4-methylphenol, etc. As a result, compared to substrate processing liquids using conventional sublimable substances, sublimation drying can be performed while effectively suppressing the collapse of the pattern, even in the case of patterns with extremely low mechanical strength.

[0018] In the above configuration, it is preferable that the substrate holding unit rotates the substrate around the rotation axis at a first rotational speed to thin the liquid film of the substrate processing liquid supplied by the supply unit to the pattern forming surface, and then rotates the substrate around the rotation axis at a second rotational speed faster than the first rotational speed used to thin the liquid film of the substrate processing liquid, thereby evaporating the solvent in the liquid film.

[0019] Furthermore, in the above configuration, the sublimation unit is a gas supply unit that supplies an inert gas toward the pattern forming surface, and the gas supply unit may also promote the formation of the solidified film by supplying the inert gas toward the pattern forming surface after the deposition of the sublimable substance during the formation of the solidified film.

[0020] Furthermore, in the above configuration, when the sublimable substance is 3,5-dimethyl-1-adamantanol, the sublimation unit is a gas supply unit that supplies an inert gas toward the pattern forming surface, and it is preferable that the gas supply unit supplies an inert gas toward the pattern forming surface while the substrate holding unit rotates the substrate around a rotation axis parallel to the vertical direction of the pattern forming surface, thereby sublimating the solidified film.

[0021] Furthermore, if the sublimable substance is at least one of 2-(1-adamantyl)-4-methylphenol and hexahydrophthalimide, the sublimation section is a heating section that heats the surface of the substrate opposite to the pattern-forming surface, and it is preferable that the heating section sublimes the solidified film by heating the solidified film through the substrate.

[0022] Furthermore, in the above configuration, it is preferable to use a solvent that has a higher vapor pressure at room temperature than the sublimable substance. This facilitates the precipitation of 2-(1-adamantyl)-4-methylphenol and the like by evaporation of the solvent, and enables the formation of a solidified film containing the sublimable substance.

[0023] Furthermore, in the above configuration, it is preferable that the solvent is at least one of methanol, butanol, isopropyl alcohol, and acetone.

[0024] Furthermore, the substrate processing liquid according to the present invention is a substrate processing liquid used to remove liquid from a substrate having a pattern-forming surface in order to solve the above-mentioned problems, and comprises a sublimable substance and a solvent, wherein the sublimable substance comprises at least one of 2-(1-adamantyl)-4-methylphenol, 3,5-dimethyl-1-adamantanol, and hexahydrophthalimide.

[0025] According to the above configuration, by including 2-(1-adamantyl)-4-methylphenol or the like as a sublimable substance in the substrate processing solution, it is possible to suppress pattern collapse and perform sublimation drying effectively, even in the case of patterns with extremely low mechanical strength, compared to substrate processing solutions using conventional sublimable substances.

[0026] Furthermore, in the above configuration, it is preferable that the solvent has a vapor pressure at room temperature greater than that of the sublimable substance. This facilitates the precipitation of 2-(1-adamantyl)-4-methylphenol and the like by evaporation of the solvent, and enables the formation of a solidified film containing the sublimable substance.

[0027] Furthermore, in the above configuration, it is preferable that the solvent is at least one of methanol, butanol, isopropyl alcohol, and acetone.

[0028] According to the present invention, compared to conventional substrate processing liquids containing sublimable substances, it is possible to suppress the collapse of patterns on the pattern formation surface of a substrate, and in particular, to effectively suppress the collapse of patterns even when the patterns have extremely low mechanical strength.

[0029] This is a plan view showing the schematic configuration of a substrate processing apparatus according to an embodiment of the present invention. This is an explanatory diagram showing the schematic configuration of a processing unit in a substrate processing apparatus. Figure 3(a) is a block diagram showing the schematic configuration of a substrate processing liquid storage section, and Figure 3(b) is an explanatory diagram showing the specific configuration of the substrate processing liquid storage section. This is a block diagram showing the schematic configuration of a gas storage section in a substrate processing apparatus. This is an explanatory diagram showing the specific configuration of a heating section in a substrate processing apparatus. This is a flowchart for explaining a substrate processing method using the substrate processing apparatus according to this embodiment. Figure 7(a) is a schematic diagram showing the state of the substrate W after the substrate processing liquid supply process is completed, and Figure 7(b) is a schematic diagram showing the state of the substrate W after the thin-film formation process is completed. Figure 8(a) is a schematic diagram showing the state of the substrate W at the start of the solidification process, Figure 8(b) is a schematic diagram showing the state after a solidified film has been formed on the surface of the substrate, and Figure 8(c) is a schematic diagram showing the state after the solidified film has been removed by sublimation. This is a graph showing an example of an image of the decrease in the thickness of the liquid film (thin film) of the substrate processing liquid on the substrate W due to the evaporation of the solvent.

[0030] One embodiment of the present invention will be described below. In this specification, "substrate" refers to various substrates such as semiconductor substrates, photomask glass substrates, liquid crystal display glass substrates, plasma display glass substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, and magneto-optical disk substrates. In this specification, "pattern-forming surface" means a surface on a substrate in which an uneven pattern is formed in any region, regardless of whether it is planar, curved, or uneven. In this specification, a substrate in which a circuit pattern or the like (hereinafter referred to as "pattern") is formed only on one main surface is used as an example. Here, the pattern-forming surface (main surface) on which the pattern is formed is referred to as the "front surface," and the main surface on the opposite side on which no pattern is formed is referred to as the "back surface." Furthermore, the surface of the substrate facing downwards is referred to as the "bottom surface," and the surface of the substrate facing upwards is referred to as the "top surface." In this embodiment, the top surface will be described as the front surface.

[0031] (Substrate Processing Solution) First, the substrate processing solution according to this embodiment will be described. The substrate processing solution of this embodiment contains a sublimable substance and a solvent. The substrate processing solution of this embodiment may consist only of a sublimable substance and a solvent. The substrate processing solution of this embodiment plays a function in assisting the drying process for removing liquid present on the pattern-forming surface of a substrate. In this specification, "sublimable" means that an element, compound, or mixture has the property of undergoing a phase transition from solid to gas or from gas to solid without passing through a liquid phase, and "sublimable substance" means a substance having such sublimability.

[0032] The sublimable substance contains at least one of 2-(1-adamantyl)-4-methylphenol, 3,5-dimethyl-1-adamantanol, and hexahydrophthalimide (hereinafter sometimes referred to as "2-(1-adamantyl)-4-methylphenol, etc."). These sublimable substances can be used individually or in combination of two or more. 2-(1-adamantyl)-4-methylphenol, etc. are each represented by the following chemical formulas.

[0033]

[0034] It is preferable that 2-(1-adamantyl)-4-methylphenol, etc., be present in a dissolved state in the substrate treatment solution. Herein, "dissolved state" means that 2-(1-adamantyl)-4-methylphenol, etc., is dissolved in, for example, 2.2 g or more of solvent at 23°C per 100 g.

[0035] The content (concentration) of 2-(1-adamantyl)-4-methylphenol, etc., can be appropriately set according to, for example, the thickness of the solidified film of the substrate processing liquid formed on the pattern-forming surface of the substrate, and the rotation speed of the substrate when sublimating the solidified film. For example, when 2-(1-adamantyl)-4-methylphenol is used as the sublimable substance, its content is preferably in the range of 2.44 vol% or more and 2.5 vol% or less of the total volume of the substrate processing liquid. By setting the content of 2-(1-adamantyl)-4-methylphenol to 2.44 vol% or more, pattern collapse can be suppressed even more effectively, even for substrates with fine patterns and large aspect ratios. On the other hand, by setting the content of 2-(1-adamantyl)-4-methylphenol to 2.5 vol% or less, it is possible to suppress the thickness of the solidified film from becoming excessively large and prevent the pattern collapse rate from becoming too high. Furthermore, the content of 2-(1-adamantyl)-4-methylphenol may be, for example, 2.44, 2.45, 2.46, 2.47, 2.48, 2.49, or 2.5 vol%, and may be within the range of any two of the values ​​exemplified here.

[0036] Furthermore, for example, when 3,5-dimethyl-1-adamantanol is used as a sublimable substance, its content is preferably within the range of 2.17 vol% or more and 3.85 vol% or less relative to the total volume of the substrate processing solution. By setting the content of 3,5-dimethyl-1-adamantanol to 2.17 vol% or more, pattern collapse can be suppressed even more effectively, even for substrates with fine patterns and large aspect ratios. On the other hand, by setting the content of 3,5-dimethyl-1-adamantanol to 3.85 vol% or less, it is possible to prevent the thickness of the solidified film from becoming excessively large and to prevent the pattern collapse rate from becoming too high. Furthermore, the content of 3,5-dimethyl-1-adamantanol may be, for example, 2.17, 2.2, 2.25, 2.3, 2.35, 2.44, 2.5, 2.55, 2.6, 2.65, 2.7, 2.78, 3.0, 3.5, or 3.85 vol%, and may also be within the range of any two of the values ​​exemplified here.

[0037] Furthermore, when hexahydrophthalimide is used as the sublimable substance, for example, its content is preferably within the range of 2.78 vol% or more and 3.23 vol% or less relative to the total volume of the substrate treatment solution. By setting the hexahydrophthalimide content to 2.78 vol% or more, pattern collapse can be suppressed even more effectively for substrates with fine patterns and large aspect ratios. On the other hand, by setting the hexahydrophthalimide content to 3.23 vol% or less, it is possible to prevent the thickness of the solidified film from becoming excessively large and to prevent the pattern collapse rate from becoming too high. Specifically, the hexahydrophthalimide content may be, for example, 2.78, 2.8, 2.9, 3.0, 3.1, 3.2, or 3.23 vol%, and may also be within the range of any two of the values ​​exemplified here.

[0038] Furthermore, in this embodiment, the substrate processing solution may contain known sublimable substances other than 2-(1-adamantyl)-4-methylphenol, etc., as long as the effects of the present invention are not impaired. In this case, the content of the other sublimable substances can be appropriately set according to their type and other factors.

[0039] The solvent can function as a solvent for dissolving 2-(1-adamantyl)-4-methylphenol, etc. Preferably, the solvent has a vapor pressure at room temperature that is greater than the vapor pressure of 2-(1-adamantyl)-4-methylphenol, etc., at room temperature. This facilitates the evaporation of the solvent to precipitate 2-(1-adamantyl)-4-methylphenol, etc. Here, in this specification, "room temperature" means a temperature within the range of 5°C to 35°C, 10°C to 30°C, or 20°C to 25°C.

[0040] The solvent is preferably at least one of the following: methanol, butanol, isopropyl alcohol, and acetone. Of these solvents, isopropyl alcohol is preferred in this embodiment because the vapor pressure of isopropyl alcohol at room temperature is greater than that of 2-(1-adamantyl)-4-methylphenol, etc. The exemplified solvents can be used individually or in combination of two or more.

[0041] The method for producing the substrate processing solution according to this embodiment is not particularly limited. For example, one method is to add crystalline material such as 2-(1-adamantyl)-4-methylphenol to a solvent at room temperature and atmospheric pressure to achieve a constant content. "Atmospheric pressure" means an environment within the range of 0.7 atmospheres to 1.3 atmospheres, centered around standard atmospheric pressure (1 atmosphere, 1013 hPa).

[0042] In the method for producing the substrate processing solution, crystalline substances such as 2-(1-adamantyl)-4-methylphenol may be added to the solvent, followed by filtration. This reduces or prevents the generation of residue originating from the substrate processing solution on the pattern-forming surface of the substrate when the solution is supplied to the pattern-forming surface and used to remove the liquid. The filtration method is not particularly limited, and for example, filter filtration can be employed.

[0043] The substrate treatment liquid of this embodiment can be stored at room temperature. However, from the perspective of suppressing the change in the concentration of 2-(1-adamantyl)-4-methylphenol, etc. due to the evaporation of the solvent, it is preferable to store it at a predetermined temperature. For example, in the case of hexahydrophthalimide or 3,5-dimethyl-1-adamantanol, it is preferable to store it at 15°C or lower. Also, in order to prevent the evaporation of the solvent, it is more preferable to store the substrate treatment liquid in a sealed dark place. When using the substrate treatment liquid stored at a low temperature, from the perspective of preventing the mixing of moisture due to condensation, it is preferable to use it after bringing the liquid temperature of the substrate treatment liquid to the use temperature or room temperature, etc.

[0044] (Substrate processing apparatus) <Overall configuration of the substrate processing apparatus> The substrate processing apparatus according to this embodiment will be described based on FIG. 1. FIG. 1 is a plan view showing the schematic configuration of the substrate processing apparatus 100 according to this embodiment. The substrate processing apparatus 100 of this embodiment is a single wafer type substrate processing apparatus used for a cleaning process (including a rinse process) for removing contaminants such as particles adhering to the substrate, and a drying process after the cleaning process.

[0045] As shown in FIG. 1, the substrate processing apparatus 100 includes a substrate processing unit 110 that performs various processes on the substrate W, and an indexer unit 120.

[0046] The indexer unit 120 has a function of supplying the substrate W to the substrate processing unit 110 or recovering the substrate W from the substrate processing unit 110. Specifically, the indexer unit 120 includes four container holding parts 121, and each container holding part 121 is provided with one container C. Examples of the container C include a FOUP (Front Opening Unified Pod) that houses a plurality of substrates W in a sealed state, a SMIF (Standard Mechanical Interface) pod, an OC (Open Cassette), etc. In addition, in this embodiment, the case where there are four container holding parts 121 is described as an example, but the present invention is not limited to this. The number of container holding parts 121 may be plural.

[0047] The indexer unit 120 further includes a first transfer unit 122 for transferring the substrate W. The first transfer unit 122 is provided between the container holding unit 121 and the substrate processing unit 110. The first transfer unit 122 includes a base portion 122a fixed to the apparatus housing, an articulated arm 122b provided rotatable about a vertical axis with respect to the base portion 122a, and a hand 122c attached to the tip of the articulated arm 122b. The hand 122c has a structure capable of placing and holding the substrate W on its upper surface. The first transfer unit 122 can access the container C held by the container holding unit 121 to take out the unprocessed substrate W from the container C or store the processed substrate W in the container C.

[0048] The substrate processing unit 110 performs a cleaning process (including a rinsing process) and a drying process after the cleaning process on the substrate. The substrate processing unit 110 includes a second transfer unit 111 disposed substantially at the center in a plan view, and four processing units 1 disposed so as to surround the second transfer unit 111. As the second transfer unit 111, for example, a substrate transfer robot can be used. The second transfer unit 111 randomly accesses each processing unit 1 and transfers the substrate W. The substrate processing unit 110 enables parallel processing of a plurality of substrates W by including a plurality of processing units 1.

[0049] <Configuration of Processing Unit> Next, the configuration of the processing unit 1 will be described based on FIGS. 2 to 5. FIG. 2 is an explanatory diagram showing an outline of the substrate processing apparatus according to the present embodiment. FIG. 3(a) is a block diagram showing a schematic configuration of the substrate processing liquid storage unit, and FIG. 3(b) is an explanatory diagram showing a specific configuration of the substrate processing liquid storage unit. FIG. 4 is a block diagram showing a schematic configuration of the gas storage unit. FIG. 5 is an explanatory diagram showing a specific configuration of the heating unit. In FIGS. 2 and 5, for the sake of clarity of the directional relationship of the illustrated elements, the XYZ orthogonal coordinate axes are appropriately displayed. In the figure, the XY plane represents a horizontal plane, and the +Z direction represents vertically upward.

[0050] The processing unit 1 comprises at least a chamber 11 which is a container for housing the substrate W, a substrate holding section 51 which holds the substrate W, a processing liquid supply section (supply section) 21 which supplies substrate processing liquid to the substrate W held in the substrate holding section 51, an IPA supply section 31 which supplies IPA (isopropyl alcohol) to the substrate W held in the substrate holding section 51, a gas supply section (sublimation section) 41 which supplies gas to the substrate W held in the substrate holding section 51, a heating section (sublimation section) 61 which heats the back surface Wb of the substrate W, a splash prevention cup 12 which collects IPA, substrate processing liquid, etc. supplied to the substrate W held in the substrate holding section 51 and discharged to the outside of the peripheral edge of the substrate W, and a rotation drive section 14 which independently rotates the arms of each part of the processing unit 1, which will be described later.

[0051] As shown in Figures 2 and 5, the substrate holding unit 51 comprises a rotation drive unit 52, a spin base 53, and chuck pins 54. The spin base 53 has a planar size slightly larger than the substrate W. Multiple chuck pins 54 are erected near the periphery of the spin base 53 to grip the periphery of the substrate W. The number of chuck pins 54 is not particularly limited, but it is preferable to provide at least three or more in order to reliably hold the circular substrate W. In this embodiment, three are arranged at equal intervals along the periphery of the spin base 53. Each chuck pin 54 comprises a substrate support pin that supports the periphery of the substrate W from below, and a substrate holding pin that presses against the outer peripheral end face of the substrate W supported by the substrate support pin to hold the substrate W.

[0052] In this embodiment, the case in which the substrate W is held by the spin base 53 and the chuck pin 54 is described as an example, but the present invention is not limited to this substrate holding method. For example, the back surface Wb of the substrate W may be held by a suction method such as a spin chuck.

[0053] The spin base 53 is connected to the rotary drive unit 52. The rotary drive unit 52 rotates around an axis A1 along the Z direction according to the operation command of the control unit 13. The rotary drive unit 52 is composed of a known belt, motor, rotating shaft 55 and casing 56. When the rotating shaft 55 rotates around axis A1, the substrate W, which is held above the spin base 53 by the chuck pin 54, rotates together with the spin base 53 around a rotation axis parallel to the vertical direction of the surface Wf of the substrate W, i.e., around axis A1.

[0054] Next, the processing liquid supply unit (supply unit) 21 will be described. The processing liquid supply unit 21 is a unit that supplies substrate processing liquid to the pattern formation surface of the substrate W. As shown in Figure 2, the processing liquid supply unit 21 comprises at least a nozzle 22, an arm 23, a pivot shaft 24, a pipe 25, a valve 26, and a substrate processing liquid storage unit 27.

[0055] The nozzle 22 is attached to the tip of a horizontally extending arm 23 and positioned above the substrate holding portion 51. The rear end of the arm 23 is rotatably supported around axis J1 by a pivot shaft 24 extending in the Z direction, and the pivot shaft 24 is fixed inside the chamber 11. The arm 23 is connected to a pivot drive unit 14 via the pivot shaft 24. The pivot drive unit 14 is electrically connected to a control unit 13 and rotates the arm 23 around axis J1 according to operation commands from the control unit 13. As the arm 23 rotates, the nozzle 22 also moves. Normally, the nozzle 22 is positioned outside the periphery of the substrate W and outside the splash prevention cup 12. When the arm 23 rotates according to the operation commands from the control unit 13, the nozzle 22 is positioned above the center of the surface Wf of the substrate W (axis A1 or its vicinity).

[0056] Valve 26 is electrically connected to the control unit 13 and is normally closed. The opening and closing of valve 26 is controlled by an operation command from the control unit 13. When valve 26 is opened by an operation command from the control unit 13, the substrate processing liquid is supplied through the piping 25 to the surface Wf of the substrate W from the nozzle 22.

[0057] As shown in Figures 3(a) and 3(b), the substrate processing liquid storage unit 27 includes at least a substrate processing liquid storage tank 271, a stirring unit 277 for stirring the substrate processing liquid in the substrate processing liquid storage tank 271, a pressurizing unit 274 for pressurizing the substrate processing liquid storage tank 271 and discharging the substrate processing liquid, and a temperature control unit 272 for heating the substrate processing liquid in the substrate processing liquid storage tank 271.

[0058] The substrate processing solution storage tank 271 includes a stock solution tank 281 for storing the stock solution of the substrate processing solution and a solvent tank 282 for storing the solvent. The stock solution tank 281 is connected to the substrate processing solution storage tank 271 via piping 283, and a valve 284 is interposed in the middle of the piping 283. The stock solution of the substrate processing solution contains at least a sublimable substance and a solvent, and the concentration of the sublimable substance is higher than the concentration of the sublimable substance contained in the substrate processing solution at the time of use. The solvent tank 282 is connected to the substrate processing solution storage tank 271 via piping 285, and a valve 286 is interposed in the middle of the piping 285. The solvent stored in the solvent tank 282 is preferably the same type as the solvent contained in the stock solution of the substrate processing solution. Valves 284 and 286 are electrically connected to the control unit 13 and are normally closed. Furthermore, the opening and closing of valves 284 and 286 are controlled by operation commands from the control unit 13.

[0059] When valve 284 is opened by an operation command from control unit 13, the stock solution of the substrate processing solution is pumped from stock solution tank 281 and supplied to the substrate processing solution storage tank 271 via piping 283. Similarly, when valve 286 is opened by an operation command from control unit 13, solvent is pumped from solvent tank 282 and supplied to the substrate processing solution storage tank 271 via piping 285. As a result, the stock solution of the substrate processing solution and the solvent are mixed in the substrate processing solution storage tank 271, diluting the stock solution and preparing a substrate processing solution containing the sublimable substance at the desired concentration. The concentration of the sublimable substance can be adjusted by adjusting the time and degree of opening of valves 284 and 286 (i.e., the flow rate of the stock solution of the substrate processing solution and the solvent) using the control unit 13.

[0060] As shown in Figure 3(b), the stirring unit 277 includes a rotating unit 279 that stirs the substrate processing liquid in the substrate processing liquid storage tank 271, and a stirring control unit 278 that controls the rotation of the rotating unit 279. The stirring control unit 278 is electrically connected to the control unit 13. The rotating unit 279 is equipped with a propeller-shaped stirring blade at the tip of its rotating shaft (the lower end of the rotating unit 279 in Figure 3(b)). The control unit 13 issues an operation command to the stirring control unit 278, causing the rotating unit 279 to rotate, which stirs the substrate processing liquid with the stirring blade, thereby homogenizing the concentration of sublimable substances in the substrate processing liquid and the temperature of the substrate processing liquid.

[0061] Furthermore, the method for making the concentration and temperature of the substrate processing liquid in the substrate processing liquid storage tank 271 uniform is not limited to the method described above, and known methods such as circulating the substrate processing liquid by providing a separate circulation pump can be used.

[0062] The pressurizing section 274 consists of a nitrogen gas tank 275, which is a source of inert gas that pressurizes the substrate processing liquid storage tank 271, a pump 276 that pressurizes the nitrogen gas, and piping 273. The nitrogen gas tank 275 is connected to the substrate processing liquid storage tank 271 by piping 273, and the pump 276 is inserted into the piping 273.

[0063] The temperature control unit 272 is electrically connected to the control unit 13 and adjusts the temperature of the substrate processing liquid stored in the substrate processing liquid storage tank 271 by heating it according to the operation commands of the control unit 13. The temperature adjustment is performed, for example, to prevent sublimable substances dissolved in the substrate processing liquid from precipitating. Preferably, the upper limit of the temperature adjustment is lower than the boiling point of the solvent, such as IPA. This prevents evaporation of the solvent and prevents the substrate processing liquid of the desired composition from being supplied to the substrate W. Furthermore, the temperature control unit 272 is not particularly limited, and known temperature control mechanisms such as resistance heaters, Peltier elements, and piping through temperature-controlled water can be used.

[0064] As shown in Figure 2, the IPA supply unit 31 is a unit that supplies IPA to the substrate W held by the substrate holding unit 51. The IPA supply unit 31 comprises a nozzle 32, an arm 33, a pivot shaft 34, piping 35, a valve 36, and an IPA tank 37.

[0065] The nozzle 32 is attached to the tip of a horizontally extending arm 33 and positioned above the substrate holding portion 51. The rear end of the arm 33 is rotatably supported around axis J2 by ​​a pivot shaft 34 extending in the Z direction, and the pivot shaft 34 is fixed inside the chamber 11. The arm 33 is connected to a pivot drive unit 14 via the pivot shaft 34. The pivot drive unit 14 is electrically connected to a control unit 13 and rotates the arm 33 around axis J2 according to operation commands from the control unit 13. As the arm 33 rotates, the nozzle 32 also moves. Normally, the nozzle 32 is positioned outside the periphery of the substrate W and outside the splash prevention cup 12. When the arm 33 rotates according to the operation commands from the control unit 13, the nozzle 32 is positioned above the center of the surface Wf of the substrate W (axis A1 or its vicinity).

[0066] Valve 36 is electrically connected to the control unit 13 and is normally closed. The opening and closing of valve 36 is controlled by an operation command from the control unit 13. When valve 36 is opened by an operation command from the control unit 13, IPA is supplied through the piping 35 to the surface Wf of the substrate W from the nozzle 32.

[0067] The IPA tank 37 is connected to the nozzle 32 via piping 35, with a valve 36 interposed in the middle of the piping 35. IPA is stored in the IPA tank 37, and the IPA in the IPA tank 37 is pressurized by a pump (not shown), and the IPA is sent from the piping 35 towards the nozzle 32.

[0068] In this embodiment, IPA is used in the IPA supply unit 31, but the present invention is not limited to IPA and may use any liquid that is soluble in sublimable substances and deionized water (DIW). Substitutes for IPA in this embodiment include methanol, ethanol, acetone, benzene, carbon tetrachloride, chloroform, hexane, decalin, tetralin, acetic acid, cyclohexanol, ether, or hydrofluoroether.

[0069] As shown in Figure 2, the gas supply unit 41 is a unit that supplies gas to the substrate W held by the substrate holding unit 51, and comprises a nozzle 42, an arm 43, a support shaft 44, a pipe 45, a valve 46, a gas storage unit 47, a shut-off plate 48, a lifting mechanism 49, and a shut-off plate rotation mechanism (not shown).

[0070] As shown in Figure 4, the gas storage unit 47 includes a gas tank 471 for storing gas and a gas temperature adjustment unit 472 for adjusting the temperature of the gas stored in the gas tank 471. The gas temperature adjustment unit 472 is electrically connected to the control unit 13 and adjusts the temperature of the gas stored in the gas tank 471 by heating or cooling it according to the operation commands of the control unit 13. The gas temperature adjustment unit 472 is not particularly limited, and known temperature adjustment mechanisms such as a Peltier element or piping through temperature-controlled water can be used.

[0071] Furthermore, as shown in Figure 2, the gas storage section 47 (more specifically, the gas tank 471) is connected to the nozzle 42 via piping 45, and a valve 46 is interposed in the middle of the piping 45. The gas in the gas storage section 47 is pressurized by a pressurizing means (not shown) and sent to the piping 45. Note that the pressurizing means can be achieved not only by pressurizing with a pump or the like, but also by compressing and storing the gas in the gas storage section 47, so any pressurizing means may be used.

[0072] Valve 46 is electrically connected to the control unit 13 and is normally closed. The opening and closing of valve 46 is controlled by an operation command from the control unit 13. When valve 46 is opened by an operation command from the control unit 13, an inert gas such as nitrogen gas stored in the gas tank 471 is discharged from the nozzle 42 through the piping 45.

[0073] The nozzle 42 is located at the tip of the support shaft 44. The support shaft 44 is held at the tip of an arm 43 that extends horizontally. As a result, the nozzle 42 is positioned above the spin base 53, and more specifically, above the center of the surface Wf of the substrate W (axis A1 or its vicinity).

[0074] The arm 43 extends in a substantially horizontal direction, and its rear end is supported by a lifting mechanism 49. The arm 43 is also connected to a lifting drive unit 16 via the lifting mechanism 49. The lifting drive unit 16 is electrically connected to a control unit 13, and by raising and lowering the lifting mechanism 49 in the vertical direction according to an operation command from the control unit 13, the arm 43 is also raised and lowered integrally. This allows the nozzle 42 and the blocking plate 48 to be brought closer to or further away from the spin base 53. Specifically, when the control unit 13 controls the operation of the lifting mechanism 49 to load and unload the substrate W to the processing unit 1, the nozzle 42 and the blocking plate 48 are raised to a position separated above the substrate holding unit 51 (the position shown in Figure 2). On the other hand, when performing the sublimation process described later, the nozzle 42 and the blocking plate 48 are lowered to a height position that is a set separation distance from the surface Wf of the substrate W. The lifting mechanism 49 is fixedly installed inside the chamber 11.

[0075] The support shaft 44 has a hollow, roughly cylindrical shape, and a gas supply pipe (not shown) is inserted inside it. The gas supply pipe is in communication with piping 45. This allows nitrogen gas stored in the gas storage section 47 to flow through the gas supply pipe. The tip of the gas supply pipe is connected to the nozzle 42 mentioned above.

[0076] The shielding plate 48 has a disc-like shape of any thickness with an opening in its center and is mounted substantially horizontally to the lower end of the support shaft 44. The lower surface of the shielding plate 48 is a substrate-facing surface that faces the surface Wf of the substrate W and is substantially parallel to the surface Wf of the substrate W. The shielding plate 48 is also formed to have a diameter equal to or greater than the diameter of the substrate W. Furthermore, the shielding plate 48 is provided so that the nozzle 42 is positioned in its opening. The shielding plate 48 is connected to a shielding plate rotation mechanism that includes an electric motor. The shielding plate rotation mechanism rotates the shielding plate 48 around the rotation axis C1 relative to the support shaft 44 in response to an operation rotation command from the control unit 13. The shielding plate rotation mechanism can also be rotated in synchronization with the rotation of the substrate W during the sublimation process described later.

[0077] The gas tank 471 stores a gas that is at least inert to the substrate processing liquid (sublimable substance), more specifically nitrogen gas. The nitrogen gas is also adjusted in the gas temperature control unit 472 to a temperature below the freezing point of the sublimable substance. The temperature of the nitrogen gas is not particularly limited as long as it is below the freezing point of the sublimable substance, but it can usually be set within the range of 0°C to 15°C. By setting the temperature of the nitrogen gas to 0°C or higher, it is possible to prevent water vapor present inside the chamber 11 from condensing and adhering to the surface Wf of the substrate W, thereby preventing adverse effects on the substrate W.

[0078] Furthermore, the nitrogen gas used in this embodiment is preferably a dry gas with a dew point of 0°C or lower. When nitrogen gas is blown onto the solidified film of the substrate processing liquid under atmospheric pressure, the sublimable substance contained in the solidified film sublimes into the nitrogen gas. Since the nitrogen gas is continuously supplied to the solidified film, the partial pressure of the gaseous sublimable substance generated by sublimation in the nitrogen gas is maintained at a level lower than the saturated vapor pressure of the gaseous sublimable substance at the temperature of the nitrogen gas. At least on the surface of the solidified film, the atmosphere is filled with gaseous sublimable substance at or below its saturated vapor pressure.

[0079] Furthermore, in this embodiment, nitrogen gas is used as the gas stored in the gas storage section 47, but the present invention is not limited to any gas that is inert to sublimable substances. Examples of alternative gases to nitrogen gas include argon gas, helium gas, or air (gas with a nitrogen gas concentration of 80% and an oxygen gas concentration of 20%). Alternatively, a mixed gas obtained by mixing several of these gases may be used. In addition, a dry inert gas in which the amount of water contained in these gases is reduced to a certain value or less may be used. The amount of water contained in the dry inert gas is preferably 1000 ppm or less, more preferably 100 ppm or less, and particularly preferably 10 ppm or less. By reducing the amount of water in the dry inert gas to 1000 ppm or less, condensation during the sublimation process can be prevented.

[0080] Furthermore, the gas supply unit 41 may be configured to incorporate a substrate processing liquid supply unit. In this case, the nozzle 22 of the substrate processing liquid supply unit is provided at the tip of the support shaft 44 so as to coexist with the nozzle 42 for discharging inert gas or the like. A supply pipe (not shown) for supplying substrate processing liquid is also inserted inside the support shaft 44, and this supply pipe is configured to communicate with the piping 25. This allows the substrate processing liquid stored in the substrate processing liquid storage unit 27 to flow through the supply pipe.

[0081] Next, the heating unit 61 will be described. The heating unit 61 has the function of heating the back surface Wb of the substrate W to sublimate the solidified film formed on the surface Wf. Specifically, as shown in Figures 2 and 5, the heating unit 61 comprises a plate body 62, a heater 63, a heater energizing unit 64, a lifting mechanism 65, and a lifting shaft 66.

[0082] The plate body 62 has a circular planar shape that is slightly smaller than the diameter of the substrate W when viewed from above. A heater 63 is provided inside the plate body 62. The heater 63 is connected to a heater energizing unit 64. Furthermore, the heater energizing unit 64 is electrically connected to a control unit 13, and power can be supplied to the heater 63 to generate heat according to the operation commands of the control unit 13. The lifting shaft 66 is inserted inside the rotating shaft 55 of the substrate holding part 51. A lifting mechanism 65 is connected to the lower end of the lifting shaft 66. The lifting mechanism 65 is electrically connected to the control unit 13, and according to the operation commands of the control unit 13, the plate body 62 is raised and lowered vertically (in the Z direction shown in Figure 6) via the lifting shaft 66. This allows the upper surface 62a of the plate body 62 to contact or separate from the back surface Wb of the substrate W. When the heater 63 is heated with the upper surface 62a of the plate body 62 in contact with the back surface Wb of the substrate W, the back surface Wb can be heated directly. Also, even when the heater 63 is heated with the upper surface 62a of the plate body 62 separated from the back surface Wb of the substrate W, the back surface Wb can be heated by radiant heat.

[0083] The splash-proof cup 12 is positioned to surround the spin base 53. The splash-proof cup 12 is connected to a lifting drive mechanism (not shown) and is capable of moving up and down in the Z direction. When supplying substrate processing liquid or IPA to the pattern-forming surface of the substrate W, the splash-proof cup 12 is positioned by the lifting drive mechanism to a predetermined position as shown in Figure 2, surrounding the substrate W held by the chuck pin 54 from the side. This allows for the collection of liquids such as substrate processing liquid and IPA that are scattered from the substrate W or the spin base 53.

[0084] Furthermore, the substrate processing apparatus 100 of this embodiment may further include a chemical solution supply unit for supplying a chemical solution to the pattern formation surface of the substrate W, and a rinse solution supply unit for supplying a rinse solution to the pattern formation surface.

[0085] The chemical supply unit and the rinse solution supply unit can be, for example, equipped with a nozzle, an arm, a pivot shaft, piping, a valve, and a chemical solution storage tank, similar to the IPA supply unit 31. Therefore, a detailed explanation of these will be omitted. The chemical solution supplied by the chemical supply unit may include, for example, at least one of the following: sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid, ammonia water, hydrogen peroxide, organic acids (e.g., citric acid, oxalic acid, etc.), organic alkalis (e.g., TMAH: tetramethylammonium hydroxide, etc.), surfactants, and corrosion inhibitors. The rinse solution supplied by the rinse solution supply unit may be, for example, DIW, carbonated water, electrolyzed ionized water, hydrogen water, ozone water, and hydrochloric acid water at a dilution concentration (e.g., about 10 to 100 ppm).

[0086] Furthermore, in the substrate processing apparatus 100 of this embodiment, the heating unit 61 can be omitted if sublimation of the solidified film by heating is not performed.

[0087] <Configuration of the Control Unit> The control unit 13 is electrically connected to each part of the processing unit 1 (see Figures 2 to 4) and controls the operation of each part. The control unit 13 is composed of a computer having an arithmetic processing unit and memory. A CPU is used as the arithmetic processing unit to perform various arithmetic operations. The memory includes ROM, which is a read-only memory for storing the board processing program, RAM, which is a read-write memory for storing various information, and a magnetic disk for storing control software and data. The magnetic disk has pre-stored board processing condition information (processing recipe) corresponding to the board W and control condition information for controlling the processing unit 1. The CPU reads the board processing condition information and control condition information into RAM and controls each part of the processing unit 1 according to its contents.

[0088] (Substrate Processing Method) Next, a substrate processing method using the substrate processing apparatus 100 of this embodiment will be described below with reference to Figures 6 to 9. Figure 6 is a flowchart for explaining the substrate processing method using the substrate processing apparatus 100 according to this embodiment. Figure 7(a) is a schematic diagram showing the state of the substrate W after the substrate processing liquid supply process is completed, and Figure 7(b) is a schematic diagram showing the state of the substrate W after the thin-film formation process is completed. Figure 8(a) is a schematic diagram showing the state of the substrate W at the start of the solidification process, Figure 8(b) is a schematic diagram showing the state in which a solidified film 73 has been formed on the surface Wf of the substrate W, and Figure 8(c) is a schematic diagram showing the state in which the solidified film 73 has been removed by sublimation. Figure 9 is a graph showing an example of an image of the decrease in the thickness of the liquid film (thin film) of the substrate processing liquid on the substrate W due to the evaporation of the solvent.

[0089] Furthermore, a pattern of raised and recessed areas Wp is formed on the substrate W by a previous process (see Figure 7(a), etc.). The pattern Wp comprises raised areas Wp1 and recessed areas Wp2. In this embodiment, the raised areas Wp1 have a height in the range of 100 nm to 600 nm and a width in the range of 5 nm to 50 nm. The shortest distance between two adjacent raised areas Wp1 (the shortest width of the recessed area Wp2) is, for example, in the range of 5 to 150 nm. The aspect ratio of the raised areas Wp1, i.e., the value obtained by dividing the height by the width (height / width), is, for example, in the range of 5 to 35.

[0090] The substrate processing method according to this embodiment includes a substrate loading and substrate rotation start step S1, a chemical solution supply step S2, a rinse solution supply step S3, a displacement solution supply step S4, a substrate processing solution supply step S5, a thin-film formation step S6, a solidification step S7, a sublimation step S8, and a substrate rotation stop and substrate unloading step S9. Unless otherwise specified, each of these steps is performed under atmospheric pressure. Here, atmospheric pressure refers to an environment of 0.7 to 1.3 atmospheres, centered around standard atmospheric pressure (1 atmosphere, 1013 hPa). In particular, when the substrate processing apparatus 100 is placed in a cleanroom under positive pressure, the environment of the substrate surface Wf will be higher than 1 atmosphere.

[0091] Step S1: Substrate loading and starting the rotation of the substrate First, the operator is instructed to execute a substrate processing program corresponding to a predetermined substrate W. Then, in preparation for loading the substrate W into the processing unit 1, the control unit 13 issues an operation command and performs the following actions. Specifically, it stops the rotation of the rotation drive unit 52 and positions the chuck pin 54 to a position suitable for receiving the substrate W. It also closes the valves 26, 36, and 46 and positions the nozzles 22, 32, and 42 to their retracted positions. Finally, it opens the chuck pin 54 using an opening / closing mechanism (not shown).

[0092] Untreated substrates W, which are sealed and housed in the container C of the indexer unit 120, are transported into the processing unit 1 by the first transport unit 122 and the second transport unit 111. Once placed on the chuck pins 54, the chuck pins 54 are closed by an opening / closing mechanism (not shown). As a result, the untreated substrates W are held by the substrate holding unit 51. The untreated substrates W are held by the substrate holding unit 51 in a substantially horizontal position.

[0093] Next, the rotation drive unit 52 of the substrate holding unit 51 rotates the spin base 53 according to the operation command of the control unit 13. This rotates the substrate W, which is held above the spin base 53 by the chuck pin 54, around the axis of rotation (around axis A1). The rotation speed (number of rotations) of the spin base 53 (rotation speed (number of rotations) of the substrate W) can be set, for example, within the range of approximately 10 rpm to 3000 rpm, preferably 800 rpm to 1200 rpm.

[0094] Step S2: Chemical Solution Supply Process Next, with the substrate W rotated by the substrate holding unit 51, a chemical solution is supplied from the chemical solution supply unit onto the surface Wf of the substrate W according to the operation command of the control unit 13. This etches the native oxide film formed on the surface Wf of the substrate W. After the etching is complete, the supply of the chemical solution is stopped.

[0095] Step S3: Rinse liquid supply process Next, with the substrate W rotated by the substrate holding unit 51, rinse liquid is supplied from the rinse liquid supply unit onto the surface Wf of the substrate W by an operation command from the control unit 13. The rinse liquid supplied to the surface Wf flows from near the center of the surface Wf of the substrate W toward the periphery of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and diffuses over the entire surface Wf of the substrate W. As a result, any chemical solution adhering to the surface Wf of the substrate W is removed by the supply of rinse liquid, and the entire surface Wf of the substrate W is covered with rinse liquid. After the entire surface Wf of the substrate W is covered with rinse liquid, the supply of rinse liquid is stopped.

[0096] Step S4: Replacement fluid supply process Next, with the substrate W rotated by the substrate holding unit 51, IPA as a replacement fluid is supplied onto the surface Wf of the substrate W. That is, the control unit 13 issues an operation command to the rotation drive unit 14 to position the nozzle 32 at the center of the surface Wf of the substrate W. Then, the control unit 13 issues an operation command to the valve 36 to open the valve 36. As a result, IPA is supplied from the IPA tank 37 to the surface Wf of the substrate W via the piping 35 and the nozzle 32.

[0097] The IPA supplied to the surface Wf of the substrate W flows from near the center of the surface Wf towards the periphery of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and diffuses over the entire surface Wf of the substrate W. As a result, the rinse liquid adhering to the surface Wf of the substrate W is removed by the supply of IPA, and the entire surface Wf of the substrate W is covered with IPA. The rotation speed of the substrate W is preferably set to such an extent that the film thickness of the IPA film is higher than the height of the protrusions Wp1 over the entire surface Wf. The amount of IPA supplied is not particularly limited and can be set as appropriate. At the end of the replacement liquid supply process, the control unit 13 issues an operation command to the valve 36 and closes the valve 36. The control unit 13 also issues an operation command to the swivel drive unit 14 and positions the nozzle 32 in the retracted position.

[0098] Step S5: Substrate Processing Liquid Supply Process (Supply Process) Next, the substrate processing liquid is supplied to the surface Wf of the substrate W to which the IPA is attached. That is, the control unit 13 issues an operation command to the rotation drive unit 52, causing the substrate W to rotate around the axis A1 at a constant speed. Subsequently, the control unit 13 issues an operation command to the swivel drive unit 14, positioning the nozzle 22 at the center of the surface Wf of the substrate W. Then, the control unit 13 issues an operation command to the valve 26, opening the valve 26. As a result, the substrate processing liquid is supplied from the substrate processing liquid storage tank 271 to the surface Wf of the substrate W via the piping 25 and the nozzle 22. The substrate processing liquid supplied to the surface Wf of the substrate W flows from near the center of the surface Wf of the substrate W toward the periphery of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and diffuses over the entire surface Wf of the substrate W. As a result, as shown in Figure 7(a), the IPA adhering to the surface Wf of the substrate W is removed by the supply of the processing solution, and the entire surface Wf of the substrate W is covered with the substrate processing solution, forming a liquid film 70 of the substrate processing solution.

[0099] At the end of the substrate processing liquid supply process, the control unit 13 issues an operation command to the valve 26 to close the valve 26. The control unit 13 also issues an operation command to the swivel drive unit 14 to position the nozzle 22 in the retracted position.

[0100] Step S6: Thinning Process Next, the liquid film 70 of the substrate processing liquid formed on the surface Wf of the substrate W is thinned. That is, the control unit 13 issues an operation command to the rotation drive unit 52, which rotates the substrate W around the axis A1 at a constant speed (first rotation speed). By doing so, the centrifugal force generated by the rotation of the substrate W is used to remove excess substrate processing liquid from the surface Wf of the substrate W. By removing it from the surface Wf of the substrate W, the liquid film 70 can be made into a thin film 71 with an optimal thickness, as shown in Figure 7(b). Note that if the liquid film 70 can be thinned by controlling the amount of substrate processing liquid supplied and the rotation speed of the substrate W in the substrate processing liquid supply process, this step may be omitted.

[0101] In this process, the first rotational speed of the substrate W is set according to the thickness of the liquid film 70. The first rotational speed is usually set in the range of 10 rpm or more and 1500 rpm or less, preferably in the range of 100 rpm or more and 1000 rpm or less, and more preferably in the range of 100 rpm or more and 500 rpm or less.

[0102] Step S7: Solidification Process Next, the solvent is evaporated from the thin film 71 of the substrate processing liquid to precipitate the sublimable substance and form a solidified film. That is, the control unit 13 issues an operation command to the rotation drive unit 52, which rotates the substrate W around the axis A1 at a second rotation speed that is faster than the first rotation speed. Since the vapor pressure of the solvent is higher than the vapor pressure of the sublimable substance corresponding to the solute, the solvent evaporates at a faster rate than the evaporation rate of the sublimable substance. As a result, as shown in Figure 8(a), the solvent in the thin film 71 begins to evaporate. Then, as shown in Figure 9, the thickness of the thin film 71 gradually decreases as the concentration of the sublimable substance gradually increases.

[0103] Furthermore, when the sublimable substance in the thin film 71 becomes supersaturated, the sublimable substance begins to precipitate, forming a solidified film 72 from the surface layer of the thin film 71. Subsequently, as shown in Figure 8(b), a solidified film 73 is formed that covers the entire surface Wf of the substrate W. The thickness of the solidified film 73 can be controlled by adjusting the concentration of the sublimable substance in the substrate processing solution.

[0104] In this process, the second rotational speed of the substrate W is faster than the first rotational speed and is within the range of 500 rpm or more and 3500 rpm or less, preferably within the range of 500 rpm or more and 3000 rpm or less, more preferably within the range of 500 rpm or more and 2000 rpm or less, and particularly preferably within the range of 500 rpm or more and 1500 rpm or less.

[0105] In this process, after the deposition of the sublimable substance, the formation of the solidified film 73 may be promoted by supplying an inert gas to the pattern-forming surface. It is preferable that the inert gas is supplied while the substrate W is rotating. By supplying an inert gas and applying a physical action to the thin film 71 on which the sublimable substance has precipitated, the formation of the solidified film 73 can be promoted. The supply of an inert gas is particularly preferable when, for example, 2-(1-adamantyl)-4-methylphenol or hexahydrophthalimide is used as the sublimable substance.

[0106] The supply of inert gas begins when the control unit 13 issues an operation command to the lifting drive unit 16, causing the lifting mechanism 49 to lower the nozzle 42 and the shut-off plate 48 until the distance between them and the surface Wf of the substrate W is a preset value, bringing them closer to the substrate W. After the nozzle 42 and the shut-off plate 48 have approached the set distance from the surface Wf of the substrate W, the control unit 13 rotates the shut-off plate 48 around axis A1 at a constant speed so as to synchronize it with the substrate W.

[0107] Next, the control unit 13 issues an operation command to the valve 46, which then opens. This supplies inert gas from the gas tank 471 to the surface Wf of the substrate W via the piping 45 and nozzle 42. At this time, the substrate W and the barrier plate 48 are rotating synchronously, and the centrifugal force generated by this rotation causes the inert gas to flow from near the center of the surface Wf of the substrate W towards the periphery of the substrate W, and diffuse over the entire surface Wf of the substrate W. This promotes the formation of the solidified film 73.

[0108] The rotation speed of the substrate W and the barrier plate 48 is not particularly limited, but is usually preferable to be the same as the second rotation speed described above. The flow rate of the inert gas is preferably in the range of 40 l / min or less, more preferably in the range of 30 l / min or more and 40 l / min or less, and even more preferably in the range of 35 l / min or more and 40 l / min or less. By setting the flow rate of the inert gas to 40 l / min or less, it is possible to prevent the collapse of the pattern caused by the spraying of the inert gas. The discharge (supply) time of the inert gas can be set considering the time required for the solidification film 73 to form.

[0109] Furthermore, the thickness of the solidified film 73 can be controlled by adjusting the concentration of the sublimable substance in the substrate processing solution. In this invention, by using 2-(1-adamantyl)-4-methylphenol or the like as the sublimable substance, a solidified film 73 can be made that has a relatively wider range of thickness in which pattern collapse can be effectively suppressed compared to conventional sublimable substances. In other words, with the substrate processing method of the present invention, it is possible to set a wide range of conditions in which pattern collapse can be effectively suppressed with respect to the thickness of the solidified film 73, resulting in an excellent process window.

[0110] Step S8: Sublimation process. Next, the solidified film 73 formed on the surface Wf of the substrate W is sublimated and removed. In this step, a method of supplying an inert gas to the pattern-forming surface to sublimate the solidified film 73 or a method of heating the solidified film 73 to sublimate it can be employed. The former method of supplying an inert gas is preferably employed when, for example, the sublimable substance is 3,5-dimethyl-1-adamantanol. The latter method of heating is preferably employed when, for example, the sublimable substance is at least one of 2-(1-adamantyl)-4-methylphenol and hexahydrophthalimide. Each case will be described below.

[0111] When the sublimation process S8 is performed by supplying an inert gas, first the control unit 13 issues an operation command to the lifting drive unit 16, causing the lifting mechanism 49 to lower the nozzle 42 and the barrier plate 48 until the distance between them and the surface Wf of the substrate W is a preset value, bringing them closer to the substrate W. After the nozzle 42 and the barrier plate 48 have approached the set distance from the surface Wf of the substrate W, the control unit 13 rotates the barrier plate 48 around the axis A1 at a constant speed so as to synchronize it with the substrate W.

[0112] Next, the control unit 13 issues an operation command to the valve 46, which opens. This supplies inert gas from the gas tank 471 to the surface Wf of the substrate W via the piping 45 and nozzle 42. At this time, the substrate W and the barrier plate 48 are rotating synchronously, and the centrifugal force generated by this rotation causes the inert gas to flow from near the center of the surface Wf of the substrate W towards the periphery of the substrate W, and diffuse over the entire surface Wf of the substrate W. This increases the contact speed between the solidified film 73 and the inert gas, thereby promoting the sublimation of the solidified film 73.

[0113] Furthermore, the air present on the surface Wf of the substrate W can be replaced with an inert gas. By replacing it with an inert gas, the solidified film 73 formed on the surface Wf is placed under the flow of the inert gas, preventing it from being exposed to air, etc., and the solidified film 73 can be sublimated while maintaining a low temperature in the space between the substrate W and the barrier plate 48. As the solidified film 73 sublimes, the heat of sublimation is removed, and the solidified film 73 is maintained below the freezing point (melting point) of the sublimable substance. Therefore, the melting of the sublimable substance contained in the solidified film 73 can be effectively prevented. Since there is no liquid phase between the patterns on the surface Wf of the substrate W, the substrate W can be dried as shown in Figure 8(c) while suppressing the collapse of the patterns.

[0114] The rotational speed of the substrate W and the shielding plate 48 is not particularly limited, but is usually within the range of 500 rpm or more and 3500 rpm or less, preferably within the range of 500 rpm or more and 3000 rpm or less, more preferably within the range of 500 rpm or more and 2000 rpm or less, and most preferably within the range of 500 rpm or more and 1500 rpm or less.

[0115] The flow rate of the inert gas is preferably in the range of 200 l / min or less, more preferably in the range of 40 l / min or more and 200 l / min or less, and even more preferably in the range of 40 l / min or more and 50 l / min or less. By setting the flow rate of the inert gas to 200 l / min or less, it is possible to prevent the collapse of the pattern caused by the spraying of the inert gas. In addition, the discharge (supply) time of the inert gas can be appropriately set according to the sublimation time of the sublimable material.

[0116] When a predetermined sublimation time has elapsed since the start of the sublimation process S8 and the solidified film 73 has been removed by sublimation, the control unit 13 issues an operation command to the valve 46, which then closes the valve 46.

[0117] Furthermore, when the sublimation process S8 is performed by heating the solidified film 73, first the lifting mechanism 65 is controlled by an operation command from the control unit 13, and as shown in Figure 5, the plate body 62 is raised so that the upper surface 62a of the plate body 62 comes into contact with the back surface Wb of the substrate W, and the substrate W is separated from the chuck pin 54. In other words, the substrate W is held only by the plate body 62 from its back surface Wb side. Furthermore, the heater energizing section 64 is controlled by an operation command from the control unit 13 to supply power to the heater 63 and generate heat, thereby heating the back surface Wb of the substrate W. As a result, the solidified film 73 formed on the surface Wf of the substrate W is heated and sublimated.

[0118] Here, heating of the substrate W may be performed with the upper surface 62a of the plate body 62 separated from the back surface Wb of the substrate W. In this case, the lifting mechanism 65 is controlled by an operation command from the control unit 13 to lower the plate body 62 and position it at an arbitrary distance from the back surface Wb of the substrate W. This creates a space between the upper surface 62a of the plate body 62 and the back surface Wb of the substrate W. The separation distance between the upper surface 62a of the plate body 62 and the back surface Wb of the substrate W is not particularly limited; for example, it should be sufficient to allow heating of the substrate W by radiant heat from the plate body 62. Subsequently, the heater energizing section 64 is controlled by an operation command from the control unit 13 to supply power to the heater 63 and generate heat. This heats the back surface Wb of the substrate W with radiant heat emitted from the upper surface 62a of the plate body 62, causing the solidified film 73 formed on the surface Wf to sublimate.

[0119] The heating conditions can be appropriately set depending on the type of sublimable substance. For example, when 2-(1-adamantyl)-4-methylphenol is used as the sublimable substance, the heating temperature (temperature of the substrate W) is preferably in the range of 80°C to 100°C, more preferably in the range of 90°C to 100°C, and particularly preferably in the range of 90°C to 95°C. The heating time is preferably in the range of 30 minutes to 50 minutes, more preferably in the range of 30 minutes to 40 minutes, and particularly preferably in the range of 30 minutes to 35 minutes. Also, for example, when hexahydrophthalimide is used as the sublimable substance, the heating temperature (temperature of the substrate W) is preferably in the range of 30°C to 100°C, more preferably in the range of 80°C to 100°C, and particularly preferably in the range of 80°C to 85°C. The heating time is preferably within the range of 30 minutes to 45 minutes, more preferably within the range of 30 minutes to 40 minutes, and particularly preferably within the range of 30 minutes to 35 minutes.

[0120] Step S9: Substrate rotation stopping and substrate removal process. After the sublimation process S8 is completed, the control unit 13 issues an operation command to the rotation drive unit 52 to stop the rotation of the spin base 53. The control unit 13 also controls the barrier plate rotation mechanism to stop the rotation of the barrier plate 48, and controls the lifting drive unit 16 to raise the barrier plate 48 from the barrier position to the retracted position.

[0121] Subsequently, the second transport unit 111 enters the internal space of the chamber 11, and the processed substrate W, which has been released from being held by the chuck pin 54, is transported out of the chamber 11, thus completing the series of substrate drying processes.

[0122] As described above, in this embodiment, by using a substrate processing liquid containing 2-(1-adamantyl)-4-methylphenol or the like as the sublimable substance, the collapse of patterns on the substrate W can be suppressed more effectively compared to conventional sublimation drying techniques using sublimable substances. In particular, this embodiment can very effectively suppress the occurrence of pattern collapse even when the pattern has extremely low mechanical strength. The pattern collapse rate is preferably 20% or less, more preferably 16% or less, and particularly preferably 10% or less. As the collapse rate, for example, the collapse rate in any seven regions can be calculated using the following formula, and the average value can be used: Collapse rate (%) = (Number of collapsed protrusions in any region) ÷ (Total number of protrusions in the region) × 100

[0123] (Modifications) The above description has described preferred embodiments of the present invention. However, the present invention is not limited to these embodiments and can be implemented in various other forms. Other main embodiments are exemplified below.

[0124] In the above-described embodiment, the case in which the sublimation step S8 is performed after the solidification step S7 is completed was explained. However, the present invention is not limited to this embodiment. For example, the sublimation step S8 may be started after the start of the solidification step S7 and may be performed in parallel with the solidification step S7. As described above, the solidified film is formed from the surface layer of the liquid film as sublimable substances precipitate due to the evaporation of the solvent. Therefore, the sublimation step S8 may be started before the completion of the solidification step S7. This makes it possible to sublimate and dry the substrate W in a short period of time.

[0125] Furthermore, the above-described embodiment was explained using the case where the gas supply unit is equipped with a shut-off plate as an example. However, the present invention is not limited to this embodiment, and for example, the sublimation process S8 may be performed using a gas supply unit that is not equipped with a shut-off plate.

[0126] Furthermore, in the above-described embodiment, the case in which the substrate W is rotated around the axis A1 at a faster rotational speed than that of the thinning process S6 to form a solidified film was explained as an example. However, the present invention is not limited to this embodiment. For example, the substrate W may be rotated around the axis A1 at a faster rotational speed than that of the thinning process S6, and furthermore, after the deposition of the sublimable substance, an inert gas may be supplied toward the surface Wf of the substrate W while forming a solidified film. Note that "after the deposition of the sublimable substance" means not only when the sublimable substance begins to precipitate in the liquid film (i.e., when the liquid film of the substrate processing solution becomes supersaturated), but also the period from the deposition of the sublimable substance until the solidified film is formed.

[0127] As a means for supplying inert gas in the solidification process S7, for example, the aforementioned gas supply unit 41 can be used. Alternatively, a gas supply unit 41 without the shut-off plate 48 may be used.

[0128] The inert gas is not particularly limited and examples include nitrogen gas, argon gas, helium gas, or air (gas with a nitrogen gas concentration of 80% and an oxygen gas concentration of 20%). Alternatively, a mixed gas of several of these gases may be used. Furthermore, a dry inert gas may be used in which the amount of water contained in these gases has been reduced to below a certain value. The amount of water contained in the dry inert gas is preferably 1000 ppm or less, more preferably 100 ppm or less, and particularly preferably 10 ppm or less.

[0129] The flow rate of the inert gas to be sprayed is preferably within the range of 200 l / min or less, more preferably within the range of 40 l / min or more and 200 l / min or less, and even more preferably within the range of 40 l / min or more and 50 l / min or less. By setting the flow rate of the inert gas to 200 l / min or less, it is possible to prevent the collapse of the pattern caused by the spraying of the inert gas. In addition, the discharge time of the inert gas can be appropriately set according to the formation time of the solidified film.

[0130] The temperature of the inert gas is preferably in the range of -50°C to 100°C, more preferably in the range of 0°C to 50°C, and particularly preferably in the range of 20°C to 50°C. Furthermore, if the temperature of the inert gas is 20°C or higher, condensation on the substrate W can be prevented.

[0131] Preferred embodiments of this invention will be described in detail below. However, unless otherwise specified, the materials and proportions described in these embodiments are not intended to limit the scope of this invention to those materials alone.

[0132] (Patterned Substrate) A silicon substrate with a model pattern formed on its surface was prepared as a patterned substrate, and coupons (test specimens) with sides of 12 mm were cut out from the silicon substrate. A pattern consisting of cylinders with a height of approximately 300 nm was adopted as the model pattern.

[0133] (Example 1) In this example, a coupon cut from the aforementioned silicon substrate was subjected to sublimation drying according to the procedure described below, and the effect of suppressing pattern collapse was evaluated.

[0134] First, the coupon was immersed in 10% by mass hydrofluoric acid for 20 seconds (chemical supply step), and then rinsed by immersion in DIW for 1 minute (rinsing solution supply step). Furthermore, the coupon, after rinsing with DIW, was immersed in IPA for 1 minute to replace the DIW present on the pattern-forming surface of the coupon with IPA (replacement solution supply step).

[0135] Next, the coupons with residual IPA on their surfaces were immersed in a substrate treatment solution (liquid temperature: 25°C) for 30 seconds at room temperature (25°C) and atmospheric pressure (1 atm) to replace the IPA present on the pattern-forming surface of the coupons with the substrate treatment solution (substrate treatment solution supply step). The substrate treatment solution used consisted of 3,5-dimethyl-1-adamantanol (a sublimable substance) at a concentration of 2.2 vol% and IPA.

[0136] Furthermore, after supplying the substrate processing liquid, the coupon was rotated around its axis at a rotational speed of 10 rpm for 5 seconds to thin the liquid film of the substrate processing liquid on the pattern formation surface (thinning process).

[0137] Next, the coupon after the thinning process was rotated around the rotation axis at a rotation speed of 1500 rpm for 13 seconds to evaporate the IPA and precipitate 3,5-dimethyl-1-adamantanol, forming a solidified film consisting of the 3,5-dimethyl-1-adamantanol (solidification process).

[0138] After a solidified film was formed on the pattern-forming surface of the coupon, nitrogen gas was blown onto this solidified film to sublimate it (sublimation process). The sublimation process was carried out while the coupon was rotated around its axis at a rotational speed of 1500 rpm. Furthermore, the nitrogen gas flow rate was set to 40 L / min. The processing time for the sublimation process was 100 seconds.

[0139] For the sublimation-dried coupons obtained as described above, the pattern collapse rate was calculated from SEM images, and the effect of suppressing pattern collapse on the pattern-forming surface was evaluated based on this collapse rate. The collapse rate was calculated by taking the collapse rate in seven arbitrary regions using the following formula and then taking the average value: Collapse rate (%) = (Number of collapsed protrusions in any given region) ÷ (Total number of protrusions in that region) × 100

[0140] As a result, the collapse rate after drying was 7.8% compared to the pattern-forming surface of the coupon before drying. This confirmed that when 3,5-dimethyl-1-adamantanol is used as the sublimable substance, pattern collapse can be suppressed very well, and that it is effective for sublimation drying.

[0141] (Example 2) In this example, the concentration of 3,5-dimethyl-1-adamantanol was changed to 2.4 vol% of the total volume of the substrate treatment solution. Otherwise, the same procedure as in Example 1 was followed, and the effect of suppressing pattern collapse on the pattern formation surface was evaluated. As a result, the collapse rate was 2.43%.

[0142] (Example 3) In this example, the concentration of 3,5-dimethyl-1-adamantanol was changed to 2.8 vol% of the total volume of the substrate processing solution. Also, the rotation speed when rotating the coupon in the sublimation process was changed to 3500 rpm. Except for these changes, the procedure was the same as in Example 1, and the effect of suppressing pattern collapse on the pattern formation surface was evaluated. As a result, the collapse rate was 1.58%.

[0143] (Example 4) In this example, the concentration of 3,5-dimethyl-1-adamantanol was changed to 3.2 vol% of the total volume of the substrate processing solution. Also, the rotation speed when rotating the coupon in the sublimation process was changed to 3500 rpm. Except for these changes, the procedure was the same as in Example 1, and the effect of suppressing pattern collapse on the pattern formation surface was evaluated. As a result, the collapse rate was 4.87%.

[0144] (Example 5) In this example, the concentration of 3,5-dimethyl-1-adamantanol was changed to 3.8 vol% of the total volume of the substrate processing solution. Also, the rotation speed when rotating the coupon in the sublimation process was changed to 3500 rpm. Except for these changes, the procedure was the same as in Example 1, and the effect of suppressing pattern collapse on the pattern formation surface was evaluated. As a result, the collapse rate was 4.52%.

[0145] (Example 6) First, the coupon was immersed in 10% by mass hydrofluoric acid for 20 seconds (chemical supply step), and then rinsed by immersion in DIW for 1 minute (rinsing liquid supply step). Furthermore, the coupon after rinsing with DIW was immersed in IPA for 1 minute to replace the DIW present on the pattern-forming surface of the coupon with IPA (replacement liquid supply step).

[0146] Next, the coupons with residual IPA on their surfaces were immersed in a substrate treatment solution (liquid temperature: 25°C) for 30 seconds at room temperature (25°C) and atmospheric pressure (1 atm) to replace the IPA present on the pattern-forming surface of the coupons with the substrate treatment solution (substrate treatment solution supply step). The substrate treatment solution used consisted of 3,5-dimethyl-1-adamantanol (a sublimable substance) at a concentration of 2.4 vol% and IPA.

[0147] Furthermore, after supplying the substrate processing liquid, the coupon was rotated around its axis at a rotational speed of 10 rpm for 11 seconds to thin the liquid film of the substrate processing liquid on the pattern formation surface (thinning process).

[0148] Next, the coupon after the thin-film formation process was rotated around the rotation axis at a rotation speed of 3500 rpm for 5 seconds to evaporate the IPA and precipitate 3,5-dimethyl-1-adamantanol, forming a solidified film consisting of the 3,5-dimethyl-1-adamantanol (solidification process).

[0149] After a solidified film was formed on the pattern-forming surface of the coupon, nitrogen gas was blown onto this solidified film to sublimate it (sublimation process). The sublimation process was carried out while the coupon was rotated around its axis at a rotational speed of 3500 rpm. Furthermore, the nitrogen gas flow rate was set to 40 L / min. The processing time for the sublimation process was 100 seconds.

[0150] The coupon obtained after sublimation drying as described above was evaluated for its effect in suppressing pattern collapse on the pattern-forming surface in the same manner as in Example 1. As a result, the collapse rate was 0.39%.

[0151] (Example 7) First, the coupon was immersed in 10% by mass hydrofluoric acid for 20 seconds (chemical supply step), and then rinsed by immersion in DIW for 1 minute (rinsing liquid supply step). Furthermore, the coupon after rinsing with DIW was immersed in IPA for 1 minute to replace the DIW present on the pattern-forming surface of the coupon with IPA (replacement liquid supply step).

[0152] Next, the coupons with residual IPA on their surfaces were immersed in a substrate treatment solution (liquid temperature: 25°C) for 30 seconds at room temperature (25°C) and atmospheric pressure (1 atm) to replace the IPA present on the pattern-forming surface of the coupons with the substrate treatment solution (substrate treatment solution supply step). The substrate treatment solution used consisted of 2.8 vol% hexahydrophthalimide (sublimable substance) and IPA.

[0153] Furthermore, after supplying the substrate processing liquid, the coupon was rotated around its axis at a rotational speed of 10 rpm for 5 seconds to thin the liquid film of the substrate processing liquid on the pattern formation surface (thinning process).

[0154] Next, the coupon after the thin-film formation process was rotated around its axis at a rotation speed of 1500 rpm for 13 seconds to evaporate the IPA. Furthermore, nitrogen gas was blown onto the coupon, which was rotating at 1500 rpm, for 100 seconds to precipitate hexahydrophthalimide. The nitrogen gas flow rate was 40 L / min. This formed a solidified film consisting of the hexahydrophthalimide (solidification process).

[0155] Next, the rotation of the coupon was stopped, and a hot plate was brought into contact with the back side of the coupon (the side opposite to the pattern formation surface), and the substrate was heated for 30 minutes to a temperature of 80°C. This caused the solidified film made of hexahydrophthalimide to sublimate (sublimation process).

[0156] The coupon obtained after sublimation drying as described above was evaluated for its effect in suppressing pattern collapse on the pattern-forming surface in the same manner as in Example 1. As a result, the collapse rate was 1.81%.

[0157] (Example 8) In this example, the concentration of hexahydrophthalimide was changed to 3.2 vol% of the total volume of the substrate treatment solution. Otherwise, the same procedure as in Example 7 was followed, and the effect of suppressing pattern collapse on the pattern formation surface was evaluated. As a result, the collapse rate was 4.9%.

[0158] (Example 9) First, the coupon was immersed in 10% by mass hydrofluoric acid for 20 seconds (chemical supply step), and then rinsed by immersion in DIW for 1 minute (rinsing liquid supply step). Furthermore, the coupon after rinsing with DIW was immersed in IPA for 1 minute to replace the DIW present on the pattern-forming surface of the coupon with IPA (replacement liquid supply step).

[0159] Next, the coupons with residual IPA on their surfaces were immersed in a substrate treatment solution (liquid temperature: 25°C) for 30 seconds at room temperature (25°C) and atmospheric pressure (1 atm) to replace the IPA present on the pattern-forming surface of the coupons with the substrate treatment solution (substrate treatment solution supply step). The substrate treatment solution used consisted of 3.2 vol% hexahydrophthalimide (sublimable substance) and IPA.

[0160] Furthermore, after supplying the substrate processing liquid, the coupon was rotated around its axis at a rotational speed of 10 rpm for 7 seconds to thin the liquid film of the substrate processing liquid on the pattern formation surface (thinning process).

[0161] Next, the coupon after the thinning process was rotated around its axis at a rotation speed of 2000 rpm for 9 seconds to evaporate the IPA. Furthermore, nitrogen gas was blown onto the coupon, which was rotating at 2000 rpm, for 104 seconds to precipitate hexahydrophthalimide. The nitrogen gas flow rate was 40 L / min. This formed a solidified film consisting of the hexahydrophthalimide (solidification process).

[0162] Next, the rotation of the coupon was stopped, and a hot plate was brought into contact with the back side of the coupon (the side opposite to the pattern formation surface), and the substrate was heated for 30 minutes to a temperature of 80°C. This caused the solidified film made of hexahydrophthalimide to sublimate (sublimation process).

[0163] The coupon obtained after sublimation drying as described above was evaluated in the same manner as in Example 7 to assess the suppression of pattern collapse on the pattern-forming surface. As a result, the collapse rate was 0.79%.

[0164] (Example 10) First, the coupon was immersed in 10% by mass hydrofluoric acid for 20 seconds (chemical supply step), and then rinsed by immersion in DIW for 1 minute (rinsing liquid supply step). Furthermore, the coupon after rinsing with DIW was immersed in IPA for 1 minute to replace the DIW present on the pattern-forming surface of the coupon with IPA (replacement liquid supply step).

[0165] Next, the coupons with residual IPA on their surfaces were immersed in a substrate treatment solution (liquid temperature: 25°C) for 30 seconds at room temperature (25°C) and atmospheric pressure (1 atm) to replace the IPA present on the pattern-forming surface of the coupons with the substrate treatment solution (substrate treatment solution supply step). The substrate treatment solution used consisted of 2.44 vol% 2-(1-adamantyl)-4-methylphenol (sublimable substance) and IPA.

[0166] Furthermore, after supplying the substrate processing liquid, the coupon was rotated around its axis at a rotational speed of 10 rpm for 5 seconds to thin the liquid film of the substrate processing liquid on the pattern formation surface (thinning process).

[0167] Next, the coupon after the thin-film formation process was rotated around its axis at a rotation speed of 2500 rpm for 13 seconds to evaporate the IPA. Furthermore, nitrogen gas was blown onto the coupon rotating at 2500 rpm for 100 seconds to precipitate 2-(1-adamantyl)-4-methylphenol. The nitrogen gas flow rate was 40 L / min. This formed a solidified film consisting of 2-(1-adamantyl)-4-methylphenol (solidification process).

[0168] Next, the rotation of the coupon was stopped, and a hot plate was brought into contact with the back side of the coupon (the side opposite to the pattern-forming surface), and the substrate was heated for 30 minutes to a temperature of 90°C. This caused the solidified film consisting of 2-(1-adamantyl)-4-methylphenol to sublimate (sublimation step).

[0169] The coupon obtained after sublimation drying as described above was evaluated for its effect in suppressing pattern collapse on the pattern-forming surface in the same manner as in Example 1. As a result, the collapse rate was 7.68%.

[0170] (Comparative Example 1) In this comparative example, a coupon cut from the aforementioned silicon substrate was subjected to sublimation drying treatment according to the procedure described below, and the effect of suppressing pattern collapse was evaluated.

[0171] First, the coupon was immersed in 0.71% by mass hydrofluoric acid for 60 seconds, and then rinsed by immersion in DIW for 60 seconds. Furthermore, the coupon, after rinsing with DIW, was immersed in IPA for 30 seconds to replace the DIW present on the pattern-forming surface of the coupon with IPA.

[0172] Next, the coupons with residual IPA on their surface were immersed in a substrate treatment solution (liquid temperature: 25°C) for 30 seconds at room temperature (25°C) and atmospheric pressure (1 atm) to replace the IPA present on the pattern-forming surface of the coupons with the substrate treatment solution. The substrate treatment solution used was a 0.71 vol% solution consisting of camphor (a sublimable substance) represented by the following chemical formula and IPA.

[0173]

[0174] Furthermore, after supplying the substrate processing liquid, the coupon was rotated around its axis at a rotational speed of 500 rpm for 5 seconds to thin the liquid film of the substrate processing liquid on the pattern formation surface.

[0175] Next, while blowing nitrogen gas onto the thinned substrate processing solution, the coupon was rotated around its axis at a rotational speed of 500 rpm. This evaporated the IPA and precipitated camphor, forming a solidified film composed of the camphor. The nitrogen gas flow rate was 40 L / min.

[0176] After a solidified film was formed on the pattern-forming surface of the coupon, the nitrogen gas blowing was stopped, and the coupon was further rotated around its axis at a rotation speed of 500 rpm to sublimate the solidified film. The processing time for the formation and sublimation of the solidified film was 55 seconds.

[0177] The coupon obtained after sublimation drying as described above was evaluated for its effect in suppressing pattern collapse on the pattern-forming surface in the same manner as in Example 1. As a result, the collapse rate was 8.32%.

[0178]

[0179] (Results) As can be seen from Table 1, in Examples 1 to 6 using 3,5-dimethyl-1-adamantanol as the sublimable substance, Examples 7 to 9 using hexahydrophthalimide, and Example 10 using 2-(1-adamantyl)-4-methylphenol, the collapse rate of the patterns was successfully suppressed. On the other hand, in Comparative Example 1, which used camphor as the sublimable substance, the collapse rate of the patterns was higher compared to Examples 1 to 10, confirming that the collapse of the patterns could not be sufficiently suppressed.

[0180] The present invention can be applied to drying techniques for removing liquid adhering to the pattern-forming surface of a substrate, and to substrate processing techniques in general that use said drying techniques to process the surface of a substrate.

[0181] 1 Processing unit 13 Control unit 21 Processing liquid supply unit 27 Substrate processing liquid storage unit 41 Gas supply unit 47 Gas storage unit 48 Shut-off plate 51 Substrate holding unit 52 Rotation drive unit 61 Heating unit 62 Plate body 62a Top surface 63 Heater 64 Heater energizing unit 65 Rotation mechanism 66 Lifting shaft 70 Liquid film 71 Thin film 72, 73 Solidified film 100 Substrate processing apparatus 110 Substrate processing unit 120 Indexer unit 271 Substrate processing liquid storage tank 272 Temperature control unit 275 Nitrogen gas tank 471 Gas tank 472 Gas temperature control unit W Substrate Wf Surface (of the substrate) Wb Back (of the substrate) Wp Pattern (of the substrate surface) Wp1 Protrusions (of the pattern) Wp2 (pattern) recess

Claims

1. A substrate processing method for processing a pattern-forming surface of a substrate, comprising: a supply step of supplying a substrate processing liquid containing a sublimable substance and a solvent to the pattern-forming surface; a solidification step of evaporating the solvent in the liquid film of the substrate processing liquid supplied to the pattern-forming surface in the supply step to precipitate the sublimable substance and form a solidified film containing the sublimable substance; and a sublimation step of sublimating the solidified film and removing the solidified film, wherein the sublimable substance contains at least one of 2-(1-adamantyl)-4-methylphenol, 3,5-dimethyl-1-adamantanol, and hexahydrophthalimide.

2. A substrate processing method according to claim 1, further comprising a thinning step of thinning the liquid film of the substrate processing liquid supplied in the supply step on the pattern forming surface by rotating the substrate at a first rotational speed around a rotation axis parallel to the perpendicular direction of the pattern forming surface, wherein the solidification step is a step of evaporating the solvent in the liquid film by rotating the substrate around the rotation axis at a second rotational speed faster than the first rotational speed.

3. A substrate processing method according to claim 1, wherein the solidification step is to promote the formation of the solidified film by supplying an inert gas to the pattern-forming surface after the deposition of the sublimable substance.

4. A substrate processing method according to claim 1, wherein the sublimable substance is 3,5-dimethyl-1-adamantanol, the sublimation step is to sublimate the solidified film by supplying an inert gas to the pattern forming surface while the substrate is rotated about a rotation axis parallel to the perpendicular direction of the pattern forming surface.

5. A substrate processing method according to claim 1, wherein the sublimable substance is at least one of 2-(1-adamantyl)-4-methylphenol and hexahydrophthalimide, the sublimation step is a substrate processing method comprising heating the solidified film to sublimate it.

6. A substrate processing method according to claim 2, wherein the solvent used has a vapor pressure at room temperature greater than that of the sublimable substance.

7. A substrate treatment method according to claim 6, wherein the solvent is at least one of methanol, butanol, isopropyl alcohol, and acetone.

8. A substrate processing apparatus for processing the pattern-forming surface of a substrate, comprising: a substrate holding unit that holds the substrate so as to be rotatable about a rotation axis parallel to the perpendicular direction of the pattern-forming surface; a supply unit that supplies a substrate processing liquid containing a sublimable substance and a solvent to the pattern-forming surface of the substrate held by the substrate holding unit; and a sublimation unit that sublimates the solidified film containing the sublimable substance and removes the solidified film, wherein the substrate holding unit evaporates the solvent in the liquid film of the substrate processing liquid supplied to the pattern-forming surface by the supply unit by rotating the substrate about the rotation axis, thereby precipitating the sublimable substance and forming a solidified film containing the sublimable substance, and the sublimable substance in the substrate processing liquid supplied by the supply unit contains at least one of 2-(1-adamantyl)-4-methylphenol, 3,5-dimethyl-1-adamantanol, and hexahydrophthalimide.

9. A substrate processing apparatus according to claim 8, wherein the substrate holding unit rotates the substrate around the rotation axis at a first rotational speed to thin the liquid film of the substrate processing liquid supplied by the supply unit to the pattern forming surface, and rotates the substrate around the rotation axis at a second rotational speed faster than the first rotational speed used to thin the liquid film of the substrate processing liquid to evaporate the solvent in the liquid film.

10. A substrate processing apparatus according to claim 8, wherein the sublimation unit is a gas supply unit that supplies an inert gas toward the pattern forming surface, and the gas supply unit also promotes the formation of the solidified film by supplying the inert gas toward the pattern forming surface after the deposition of the sublimable substance during the formation of the solidified film.

11. A substrate processing apparatus according to claim 8, wherein the sublimable substance is 3,5-dimethyl-1-adamantanol, the sublimation unit is a gas supply unit that supplies an inert gas toward the pattern forming surface, and the gas supply unit sublimes the solidified film by supplying an inert gas toward the pattern forming surface while the substrate holding unit rotates the substrate about a rotation axis parallel to the perpendicular direction of the pattern forming surface.

12. A substrate processing apparatus according to claim 8, wherein the sublimable substance is at least one of 2-(1-adamantyl)-4-methylphenol and hexahydrophthalimide, the sublimation unit is a heating unit that heats the surface of the substrate opposite to the pattern-forming surface, and the heating unit sublimes the solidified film by heating the solidified film through the substrate.

13. A substrate processing apparatus according to claim 9, wherein the solvent used has a vapor pressure at room temperature greater than that of the sublimable substance.

14. A substrate processing apparatus according to claim 13, wherein the solvent is at least one of methanol, butanol, isopropyl alcohol, and acetone.

15. A substrate treatment solution used for removing liquid from a substrate having a pattern-forming surface, comprising a sublimable substance and a solvent, wherein the sublimable substance comprises at least one of 2-(1-adamantyl)-4-methylphenol, 3,5-dimethyl-1-adamantanol, and hexahydrophthalimide.

16. A substrate processing solution according to claim 15, wherein the solvent has a vapor pressure at room temperature greater than that of the sublimable substance.

17. A substrate processing solution according to claim 16, wherein the solvent is at least one of methanol, butanol, isopropyl alcohol, and acetone.

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