Substrate processing method, substrate processing apparatus, and processing liquid

Abstract

To provide a substrate processing method, a substrate processing apparatus, and a process liquid with which a substrate can be appropriately dried.SOLUTION: The present invention relates to a substrate processing method, a substrate processing apparatus, and a process liquid. The substrate processing method includes a process liquid supply step, a solidified film forming step, and a sublimation step. In the process liquid supply step, the process liquid is supplied to a substrate. The process liquid includes a sublimable material and a solvent. In the solidified film forming step, the solvent evaporates from the process liquid on the substrate. In the solidified film forming step, a solidified film is formed on the substrate. The solidified film includes the sublimable material. In the sublimation step, the solidified film sublimes. The sublimation of the solidified film dries the substrate. The vapor pressure of the sublimable material at room temperature is 0.1 Pa or more and 1.0 Pa or less.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] This invention relates to a substrate processing method, a substrate processing apparatus, and a processing liquid. The substrate is, for example, a semiconductor wafer, a substrate for a liquid crystal display, a substrate for an organic EL (Electroluminescence), a substrate for an FPD (Flat Panel Display), a substrate for an optical display, a substrate for a magnetic disk, a substrate for an optical disk, a substrate for a magneto-optical disk, a substrate for a photomask, or a substrate for a solar cell.

Background Art

[0002] Patent Document 1 discloses a substrate processing method for processing a substrate on which a pattern is formed. The substrate processing method includes a processing liquid supply step, a solidified film formation step, and a sublimation step. In the processing liquid supply step, the processing liquid is supplied to the substrate. The processing liquid contains a solvent and a sublimable substance. In the solidified film formation step, the solvent evaporates from the processing liquid on the substrate, and a solidified film is formed on the substrate. In the sublimation step, the solidified film sublimates. In the sublimation step, the solidified film changes to a gas without passing through a liquid state. Due to the sublimation of the solidified film, the solidified film is removed from the substrate. Due to the sublimation of the solidified film, the substrate is dried.

[0003] Patent Document 1 further discloses processing conditions for appropriately processing the substrate. The processing conditions have a certain range. The range of the processing conditions is also called a process window.

[0004] The processing conditions include the conditions of the processing liquid. The conditions of the processing liquid relate to, for example, the mixing ratio of the sublimable substance and the solvent. The conditions of the processing liquid relate to, for example, the concentration of the processing liquid. The conditions of the processing liquid have a certain range. The range of the conditions of the processing liquid is one of the process windows. When the processing liquid satisfies the conditions of the processing liquid in the substrate processing method, the substrate is appropriately processed. For example, when the processing liquid satisfies the conditions of the processing liquid, the pattern on the substrate is protected. When the processing liquid does not satisfy the conditions of the processing liquid, the substrate is not appropriately processed. For example, when the processing liquid does not satisfy the conditions of the processing liquid, the pattern on the substrate significantly collapses.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the conventional substrate processing method, the conditions of the processing liquid are strict. In other words, the range of the conditions of the processing liquid is narrow. The process window regarding the processing liquid is narrow.

[0007] For this reason, it may be difficult for the processing liquid to satisfy the conditions of the processing liquid. For example, it may be difficult to manage the processing liquid so as to satisfy the conditions of the processing liquid. As a result, it may be difficult to appropriately process the substrate. For example, it may be difficult to appropriately protect the pattern on the substrate.

[0008] The present invention has been made in view of such circumstances, and an object thereof is to provide a substrate processing method, a substrate processing apparatus, and a processing liquid capable of appropriately drying a substrate.

Means for Solving the Problems

[0009] In order to achieve such an object, the present invention has the following configuration. That is, the present invention is a substrate processing method for processing a substrate on which a pattern is formed, including a processing liquid supply step of supplying a processing liquid containing a sublimable substance and a solvent to the substrate, an evaporation step of evaporating the solvent from the processing liquid on the substrate to form a solidified film containing the sublimable substance on the substrate, and a sublimation step of sublimating the solidified film, and the vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less.

[0010] The substrate processing method is for processing a substrate on which a pattern is formed. It includes a treatment liquid supply step, a solidified film formation step, and a sublimation step. In the treatment liquid supply step, the treatment liquid is supplied to the substrate. The treatment liquid contains a sublimable substance and a solvent. In the solidified film formation step, the solvent evaporates from the treatment liquid on the substrate. In the solidified film formation step, a solidified film is formed on the substrate. The solidified film contains a sublimable substance. In the sublimation step, the solidified film sublimates. Due to the sublimation of the solidified film, the substrate is dried.

[0011] Here, the vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions for the treatment liquid for appropriately processing the substrate are looser. In other words, the process window regarding the treatment liquid is wider. Thus, it is easier to appropriately dry the substrate.

[0012] As described above, according to this substrate processing method, the substrate is appropriately dried.

[0013] In the above-described substrate processing method, the solubility of the sublimable substance in the solvent is preferably 150 vol% or more at room temperature. The conditions for the treatment liquid for appropriately processing the substrate are even looser. Thus, it is even easier to appropriately dry the substrate.

[0014] In the above-described substrate processing method, the sublimable substance is preferably 4-tert-butylphenol. The vapor pressure of 4-tert-butylphenol at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions for the treatment liquid for appropriately processing the substrate are looser. Thus, it is easier to appropriately dry the substrate.

[0015] In the above-described substrate processing method, the sublimable substance is preferably acetophenone oxime. The vapor pressure of acetophenone oxime at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions for the treatment liquid for appropriately processing the substrate are looser. Thus, it is easier to appropriately dry the substrate.

[0016] In the above-described substrate processing method, it is preferable that the solvent is isopropyl alcohol. The solubility of 4-tert-butylphenol in isopropyl alcohol is 150 vol% or more at room temperature. The solubility of acetophenone oxime in isopropyl alcohol is 150 vol% or more at room temperature. Therefore, the conditions for the processing liquid for appropriately processing the substrate are even looser. Thus, it is even easier to appropriately dry the substrate.

[0017] In the above-described substrate processing method, the ratio of the volume of the sublimable substance for generating the processing liquid to the volume of the solvent for generating the processing liquid is defined as the blending ratio (vol%). The probability that the pattern on the substrate collapses when the substrate is processed in the processing liquid supply step, the solidified film forming step, and the sublimation step is defined as the collapse rate (%). Among the plurality of collapse rates (%) obtained by changing the blending ratio, the smallest collapse rate is defined as the minimum collapse rate (%). The value obtained by adding 5% to the minimum collapse rate is defined as the first reference value (%). The range of the blending ratio when the collapse rate is equal to or less than the first reference value is defined as the first range. The first range preferably has a width of 10 or more.

[0018] When the blending ratio is within the first range, the collapse rate is equal to or less than the first reference value. The first reference value is the value obtained by adding 5% to the minimum collapse rate. Therefore, when the blending ratio is within the first range, the collapse rate is low. When the blending ratio is within the first range, the pattern on the substrate is preferably protected. When the blending ratio is within the first range, the substrate is appropriately dried.

[0019] The first range has a width of 10 or more. That is, the width of the first range is wide. Here, the blending ratio is one of the conditions of the processing liquid. The first range corresponds to the range of the conditions of the processing liquid. The first range corresponds to the process window regarding the processing liquid. Therefore, the conditions of the processing liquid are loose. The process window regarding the processing liquid is wide. Thus, it is even easier to appropriately dry the substrate.

[0020] Note that the "mixing ratio" can also be said to be the ratio of the volume of the sublimable substance used to produce the treatment liquid to the volume of the solvent used to produce the treatment liquid.

[0021] The "collapse rate" can also be said to be, for example, the ratio of the collapsed patterns on the substrate to the patterns on the substrate. The pattern includes a plurality of convex portions. In this case, the "collapse rate" can also be said to be the ratio of the number of collapsed convex portions to the number of convex portions.

[0022] The "plurality of collapse rates (%) obtained by changing the mixing ratio" can also be said to be the plurality of collapse rates (%) obtained at different said mixing ratios.

[0023] The "range of the mixing ratio when the collapse rate is equal to or less than the first reference value" can also be said to be the range of the mixing ratio at which a collapse rate equal to or less than the first reference value is obtained.

[0024] In the substrate processing method described above, when the maximum height of the cured film is 2.5 times the height of the pattern, it is preferable that the collapse rate is equal to or less than the first reference value. The process window for the treatment liquid is wider. Therefore, it is easier to appropriately dry the substrate.

[0025] In the substrate processing method described above, when the maximum height of the cured film is 4.0 times the height of the pattern, it is preferable that the collapse rate is equal to or less than the first reference value. The process window for the treatment liquid is wider. Therefore, it is easier to appropriately dry the substrate.

[0026] In the above-described substrate processing method, the ratio of the volume of the sublimable substance for generating the treatment liquid to the volume of the solvent for generating the treatment liquid is defined as the mixing ratio (vol%). The probability that the pattern on the substrate collapses when the substrate is processed in the treatment liquid supply step, the solidified film formation step, and the sublimation step is defined as the collapse rate (%). Among the plurality of collapse rates (%) obtained by changing the mixing ratio, the smallest collapse rate is defined as the minimum collapse rate (%). The mixing ratio when the collapse rate is the minimum collapse rate is defined as the optimum mixing ratio (vol%). A value obtained by adding 10 vol% to the optimum mixing ratio is defined as the first mixing ratio (vol%). The collapse rate when the mixing ratio is the first mixing ratio is defined as the first collapse rate (%). A value obtained by adding 10% to the minimum collapse rate is defined as the second reference value (%). It is preferable that the first collapse rate is lower than the second reference value.

[0027] When the mixing ratio is the optimum mixing ratio, the collapse rate is the minimum collapse rate. When the mixing ratio is the first mixing ratio, the collapse rate is the first collapse rate. Here, the first mixing ratio is a value obtained by adding 10 vol% to the optimum mixing ratio.

[0028] The first collapse rate is lower than the second reference value. Here, the second reference value is a value obtained by adding 10% to the minimum collapse rate. Therefore, when the mixing ratio increases by 10 vol% from the optimum mixing ratio, the collapse rate increases by less than 10% from the minimum collapse rate. In other words, when the increase amount of the mixing ratio from the optimum mixing ratio is 10, the increase amount of the collapse rate from the minimum collapse rate is less than 10. Thus, when the mixing ratio increases by 10 vol% from the optimum mixing ratio, the collapse rate does not increase significantly. Therefore, when the mixing ratio is within the range from the optimum mixing ratio to the first mixing ratio, the substrate is appropriately dried.

[0029] Here, the mixing ratio is one of the conditions of the treatment liquid. The range of the mixing ratio from the optimum mixing ratio to the first mixing ratio corresponds to the range of the conditions of the treatment liquid. The range of the mixing ratio from the optimum mixing ratio to the first mixing ratio corresponds to the process window regarding the treatment liquid. Therefore, the conditions of the treatment liquid are loose. The process window regarding the treatment liquid is wide. Thus, it is easier to appropriately dry the substrate.

[0030] Note that the "mixing ratio when the collapse rate is the minimum collapse rate" can also be said to be the mixing ratio at which the minimum collapse rate is obtained.

[0031] In the above-described substrate processing method, the minimum collapse rate is preferably 5% or less.

[0032] As described above, when the mixing ratio is within the first range, the collapse rate is equal to or less than the first reference value. Here, when the minimum collapse rate is 5% or less, the first reference value is 10% or less. Therefore, when the mixing ratio is within the first range, the collapse rate is 10% or less. Thus, when the mixing ratio is within the first range, the collapse rate is low. When the mixing ratio is within the first range, the pattern on the substrate is preferably protected. Therefore, it is easier to appropriately dry the substrate.

[0033] When the mixing ratio is the optimum mixing ratio, the collapse rate is the minimum collapse rate. When the mixing ratio is the first mixing ratio, the collapse rate is the first collapse rate that is lower than the second reference value. Here, when the minimum collapse rate is 5% or less, the second reference value is 15% or less. When the minimum collapse rate is 5% or less, the first collapse rate is less than 15%. Therefore, when the mixing ratio is the optimum mixing ratio, the collapse rate is 5% or less. Thus, when the mixing ratio is the first mixing ratio, the collapse rate is less than 15%. When the mixing ratio is within the range from the optimum mixing ratio to the first mixing ratio, the collapse rate is low. When the mixing ratio is within the range from the optimum mixing ratio to the first mixing ratio, the pattern on the substrate is preferably protected. Therefore, it is easier to appropriately dry the substrate.

[0034] In the above-described substrate processing method, the minimum collapse rate is preferably 1% or less.

[0035] When the minimum collapse rate is 1% or less, the first reference value is 6% or less. Therefore, when the mixing ratio is within the first range, the collapse rate is 6% or less. Thus, when the mixing ratio is within the first range, the collapse rate is even lower. When the mixing ratio is within the first range, the pattern on the substrate is even more preferably protected. Therefore, it is even easier to appropriately dry the substrate.

[0036] When the minimum collapse rate is 1% or less, the second reference value is 11% or less. When the minimum collapse rate is 1% or less, the first collapse rate is less than 11%. Therefore, when the mixing ratio is the optimal mixing ratio, the collapse rate is 1% or less. When the mixing ratio is the first mixing ratio, the collapse rate is less than 11%. Thus, when the mixing ratio is within the range from the optimal mixing ratio to the first mixing ratio, the collapse rate is even lower. When the mixing ratio is within the range from the optimal mixing ratio to the first mixing ratio, the pattern on the substrate is protected more suitably. Therefore, it is easier to dry the substrate appropriately.

[0037] In the above-described substrate processing method, the ratio of the volume of the sublimable substance for generating the treatment liquid to the volume of the solvent for generating the treatment liquid is defined as the mixing ratio (vol%). The probability that the pattern on the substrate collapses when the substrate is processed in the treatment liquid supply step, the solidified film formation step, and the sublimation step is defined as the collapse rate (%). The range of the mixing ratio when the collapse rate is 20 (%) or less is defined as the second range, and the second range preferably has a width of 10 or more.

[0038] When the mixing ratio is within the second range, the collapse rate is 20 (%) or less. Therefore, when the mixing ratio is within the second range, the collapse rate is low. When the mixing ratio is within the second range, the pattern on the substrate is protected suitably. When the mixing ratio is within the second range, the substrate is processed appropriately.

[0039] The second range has a width of 10 or more. That is, the width of the second range is wide. Here, the mixing ratio is one of the conditions of the treatment liquid. The second range corresponds to the range of the conditions of the treatment liquid. The second range corresponds to the process window regarding the treatment liquid. Therefore, the conditions of the treatment liquid are loose. The process window regarding the treatment liquid is wide. Thus, it is easier to dry the substrate appropriately.

[0040] Note that the "range of the mixing ratio when the collapse rate is 20 (%) or less" can also be said to be the range of the mixing ratio at which a collapse rate of 20 (%) or less is obtained.

[0041] In the substrate processing method described above, when the maximum height of the solidified film is 3.5 times the height of the pattern, it is preferable that the collapse rate is 20% or less. The process window regarding the processing liquid is wider. Therefore, it is easier to appropriately dry the substrate.

[0042] In the substrate processing method described above, when the maximum height of the solidified film is 4.0 times the height of the pattern, it is preferable that the collapse rate is 20% or less. The process window regarding the processing liquid is wider. Therefore, it is easier to appropriately dry the substrate.

[0043] The present invention is a substrate processing apparatus including a substrate holding unit that holds a substrate, and a processing liquid supply unit that supplies a processing liquid containing a sublimable substance and a solvent to the substrate held by the substrate holding unit, and the vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less.

[0044] The substrate processing apparatus includes a substrate holding unit and a processing liquid supply unit. The substrate holding unit holds the substrate. The processing liquid supply unit supplies the processing liquid to the substrate held by the substrate holding unit. The processing liquid contains a sublimable substance and a solvent. Therefore, when the processing liquid is supplied to the substrate, the solvent evaporates from the processing liquid on the substrate. By evaporation of the solvent, a solidified film is formed on the substrate. The solidified film contains a sublimable substance. Therefore, the solidified film sublimates. By sublimation of the solidified film, the substrate is dried.

[0045] Here, the vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions of the processing liquid for appropriately processing the substrate are looser. In other words, the process window regarding the processing liquid is wider. Therefore, it is easier to appropriately dry the substrate.

[0046] As described above, according to the present substrate processing apparatus, the substrate is appropriately dried.

[0047] In the above-described substrate processing apparatus, the solubility of the sublimable substance in the solvent is preferably 150 vol% or more at room temperature. The conditions for the processing liquid for appropriately processing the substrate are even looser. Therefore, it is even easier to appropriately dry the substrate.

[0048] The present invention relates to a processing liquid used for drying a substrate on which a pattern is formed, the processing liquid including a sublimable substance and a solvent, and the vapor pressure of the sublimable substance at room temperature being 0.1 Pa or more and 1.0 Pa or less.

[0049] The processing liquid is used for drying a substrate on which a pattern is formed. Specifically, the processing liquid is a drying aid liquid. The processing liquid includes a sublimable substance and a solvent.

[0050] [[ID=il]] Here, the vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less. For this reason, the conditions for the processing liquid for appropriately processing the substrate are looser. In other words, the process window regarding the processing liquid is wider. Therefore, by using the processing liquid, it is easier to appropriately dry the substrate. Specifically, by using the processing liquid, it is easier to dry the substrate while preferably protecting the pattern on the substrate. Thus, the processing liquid is useful for drying the substrate.

[0051] As described above, the substrate is appropriately dried using the processing liquid.

[0052] In the above-described processing liquid, the solubility of the sublimable substance in the solvent is preferably 150 vol% or more at room temperature. The conditions for the processing liquid for appropriately processing the substrate are even looser. For this reason, it is even easier to appropriately dry the substrate using the processing liquid. Therefore, the substrate is dried even more appropriately using the processing liquid.

[0053] In the above-described processing liquid, the sublimable substance is preferably 4-tert-butylphenol. The vapor pressure of 4-tert-butylphenol at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions for the processing liquid for appropriately processing the substrate are looser. Accordingly, it is easier to appropriately dry the substrate using the processing liquid.

[0054] In the above-described processing liquid, the sublimable substance is preferably acetophenone oxime. The vapor pressure of acetophenone oxime at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions for the processing liquid for appropriately processing the substrate are looser. Accordingly, it is easier to appropriately dry the substrate using the processing liquid.

[0055] In the above-described processing liquid, the solvent is preferably isopropyl alcohol. The solubility of 4-tert-butylphenol in isopropyl alcohol is 150 vol% or more at room temperature. The solubility of acetophenone oxime in isopropyl alcohol is 150 vol% or more at room temperature. Therefore, the conditions for the processing liquid for appropriately processing the substrate are even looser. Accordingly, it is even easier to appropriately dry the substrate using the processing liquid.

Advantages of the Invention

[0056] According to the substrate processing method, the substrate processing apparatus, and the processing liquid of the present invention, the substrate is appropriately dried.

Brief Description of the Drawings

[0057]

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Best Mode for Carrying Out the Invention

[0058] Hereinafter, with reference to the drawings, a substrate processing method, a substrate processing apparatus, and a processing liquid of the present invention will be described.

[0059] <1. Substrate> The substrate W is, for example, a semiconductor wafer, a substrate for a liquid crystal display, a substrate for an organic EL (Electroluminescence), a substrate for an FPD (Flat Panel Display), a substrate for an optical display, a substrate for a magnetic disk, a substrate for an optical disk, a substrate for a magneto-optical disk, a substrate for a photomask, or a substrate for a solar cell. The substrate W has a thin flat plate shape. The substrate W has a substantially circular shape in plan view.

[0060] FIG. 1 is a diagram schematically showing a part of the substrate W. The substrate W has a pattern WP. The pattern WP is formed on the surface of the substrate W.

[0061] The pattern WP has, for example, a concavo-convex shape. The pattern WP has, for example, a plurality of convex portions W1. The convex portion W1 is a part of the substrate W. The convex portion W1 is a structure. The convex portion W1 is composed of, for example, at least any one of a silicon oxide film (SiO2), a silicon nitride film (SiN), and a polysilicon film. The convex portion W1 protrudes upward from the surface of the substrate W, for example. The plurality of convex portions W1 are separated from each other. The plurality of convex portions W1 are arranged in the horizontal direction with respect to each other, for example. The convex portion W1 defines a concave portion A. The concave portion A is a space. The concave portion A is located between two adjacent convex portions W1. The concave portion A is adjacent to the side of the convex portion W1. The concave portion A is open upward, for example.

[0062] The convex portion W1 has a height HP. Specifically, the convex portion W1 has a base end W1p and a tip end W1d. The base end W1p corresponds to the proximal end of the convex portion W1. The tip end W1d corresponds to the distal end of the convex portion W1. The height HP corresponds to the distance between the base end W1p and the tip end W1d. In this specification, the height HP is appropriately referred to as the height HP of the pattern WP.

[0063] <2. Processing Liquid (Drying Aid Liquid)> In this specification, the processing liquid used for drying the substrate W is simply referred to as the "processing liquid". The processing liquid has a function of assisting in drying the substrate W. The processing liquid can be paraphrased as a drying aid liquid.

[0064] The processing liquid contains a sublimable substance. The sublimable substance has sublimability. "Sublimability" refers to the property of a single substance, compound, or mixture to undergo a phase transition from a solid to a gas, or from a gas to a solid, without passing through a liquid phase.

[0065] The sublimable substance has a vapor pressure of 0.1 Pa or more and 1.0 Pa or less at normal temperature. Here, normal temperature includes room temperature. Normal temperature is, for example, a temperature in the range of 5°C or more and 35°C or less. Normal temperature is, for example, a temperature in the range of 10°C or more and 30°C or less. The value of the vapor pressure is indicated as an absolute pressure based on absolute vacuum in this specification.

[0066] The sublimable substance contains, for example, either 4-tert-butylphenol or acetophenone oxime. For example, the sublimable substance contains, for example, only 4-tert-butylphenol. For example, the sublimable substance contains, for example, only acetophenone oxime.

[0067] 4-tert-butylphenol is represented by the following chemical formula (1).

[0068]

Chem.

[0069] Acetophenone oxime is represented by the following chemical formula (2).

[0070]

Chem.

[0071] The vapor pressure of 4-tert-butylphenol at normal temperature is 0.1 Pa or more and 1.0 Pa or less. Specifically, the vapor pressure of 4-tert-butylphenol at 25 degrees is 0.54 Pa. The vapor pressure of acetophenone oxime at normal temperature is also 0.1 Pa or more and 1.0 Pa or less. Specifically, the vapor pressure of acetophenone oxime at 25 degrees is 0.27 Pa.

[0072] The vapor pressure of the sublimable substance at normal temperature is not lower than 0.1 Pa. The sublimable substance does not include compounds having a vapor pressure lower than 0.1 Pa at normal temperature.

[0073] The vapor pressure of the sublimable substance at normal temperature is not higher than 1.0 Pa. The sublimable substance does not include compounds having a vapor pressure higher than 1.0 Pa at normal temperature.

[0074] For example, cyclohexanone oxime has a vapor pressure higher than 1.0 Pa at normal temperature. Specifically, the vapor pressure of cyclohexanone oxime at 25 degrees is 1.45 Pa. Therefore, the sublimable substance does not include cyclohexanone oxime. For example, pinacolin oxime has a vapor pressure higher than 1.0 Pa at normal temperature. Specifically, the vapor pressure of pinacolin oxime at 25 degrees is 35.3 Pa. Therefore, the sublimable substance does not include cyclohexanone oxime.

[0075] The treatment liquid contains a solvent. The solvent dissolves the sublimable substance. The sublimable substance in the treatment liquid is dissolved in the solvent. That is, the treatment liquid contains the solvent and the sublimable substance dissolved in the solvent. The sublimable substance corresponds to the solute of the treatment liquid.

[0076] It is preferable that the ability of the solvent to dissolve the sublimable substance is high.

[0077] The ability of a solvent to dissolve a sublimable substance is indicated, for example, by the solubility of the sublimable substance in the solvent. Hereinafter, the solubility of the sublimable substance in the solvent will be referred to as solubility Rm as appropriate. Solubility Rm is the limit amount of the sublimable substance that can dissolve in a certain amount of the solvent. As the solubility Rm increases, the ability of the solvent to dissolve the sublimable substance increases. Therefore, it is preferable that the solubility Rm is high.

[0078] Generally, the solubility Rm varies with temperature. The treatment liquid is used at room temperature. For this reason, it is preferable that the solubility Rm is high at room temperature. The solubility Rm is preferably 150 vol% or more at room temperature.

[0079] For example, when the maximum volume of the sublimable substance that can dissolve in a solvent of volume Q2c is Q1m, the solubility Rm is the ratio of the maximum volume Q1m to the volume Q2c. Specifically, the solubility Rm is defined by the following formula. Solubility Rm = (Maximum volume Q1m) / (Volume Q2c) * 100 (vol%) When the solvent of volume Q2c dissolves the maximum volume Q1m of the sublimable substance, the treatment liquid is in a saturated state.

[0080] Furthermore, the solvent has a relatively high vapor pressure at room temperature. For example, it is preferable that the vapor pressure of the solvent at room temperature is higher than the vapor pressure of the sublimable substance at room temperature.

[0081] The solvent is, for example, an organic solvent. The solvent is, for example, an alcohol.

[0082] The solvent contains, for example, isopropyl alcohol (IPA). The solvent contains, for example, only isopropyl alcohol (IPA).

[0083] When the solvent is isopropyl alcohol and the sublimable substance is 4-tert-butylphenol, the solubility Rm is 150 vol% or more at room temperature. Specifically, when the solvent is isopropyl alcohol and the sublimable substance is 4-tert-butylphenol, the solubility Rm is 171 vol% at 25 degrees.

[0084] When the solvent is isopropyl alcohol and the sublimable substance is acetophenone oxime, the solubility Rm is 150 vol% or more at room temperature. Specifically, when the solvent is isopropyl alcohol and the sublimable substance is acetophenone oxime, the solubility Rm is 186 vol% at 25 degrees.

[0085] Furthermore, the vapor pressure of isopropyl alcohol at room temperature is higher than the vapor pressure of 4-tert-butylphenol at room temperature. The vapor pressure of isopropyl alcohol at room temperature is higher than the vapor pressure of acetophenone oxime at room temperature.

[0086] The treatment liquid consists of, for example, only the sublimable substance and the solvent. The treatment liquid consists of, for example, only 4-tert-butylphenol and isopropyl alcohol. The treatment liquid consists of, for example, only acetophenone oxime and isopropyl alcohol.

[0087] <3. Outline of the Substrate Processing Apparatus> FIG. 2 is a plan view showing the inside of the substrate processing apparatus 1 of the embodiment. The substrate processing apparatus 1 performs processing on the substrate W. The processing in the substrate processing apparatus 1 includes a drying process.

[0088] The substrate processing apparatus 1 includes an indexer unit 3 and a processing block 7. The processing block 7 is connected to the indexer unit 3. The indexer unit 3 supplies the substrate W to the processing block 7. The processing block 7 performs processing on the substrate W. The indexer unit 3 recovers the substrate W from the processing block 7.

[0089] In this specification, for convenience, the direction in which the indexer unit 3 and the processing block 7 are arranged is referred to as the "front-rear direction X". The front-rear direction X is horizontal. Among the front-rear direction X, the direction from the processing block 7 toward the indexer unit 3 is referred to as "front". The direction opposite to the front is referred to as "rear". The horizontal direction orthogonal to the front-rear direction X is referred to as the "width direction Y". One direction of the "width direction Y" is appropriately referred to as "right". The direction opposite to the right is referred to as "left". The direction perpendicular to the horizontal direction is referred to as the "vertical direction Z". In each figure, for reference, front, rear, right, left, up, and down are appropriately shown.

[0090] The indexer unit 3 includes a plurality (for example, four) of carrier mounting parts 4. Each carrier mounting part 4 mounts one carrier C. The carrier C houses a plurality of substrates W. The carrier C is, for example, a FOUP (Front Opening Unified Pod), a SMIF (Standard Mechanical Interface), or an OC (Open Cassette).

[0091] The indexer unit 3 includes a transfer mechanism 5. The transfer mechanism 5 is disposed behind the carrier mounting part 4. The transfer mechanism 5 transfers the substrate W. The transfer mechanism 5 can access the carrier C mounted on the carrier mounting part 4. The transfer mechanism 5 includes a hand 5a and a hand drive part 5b. The hand 5a supports the substrate W. The hand drive part 5b is connected to the hand 5a. The hand drive part 5b moves the hand 5a. The hand drive part 5b moves the hand 5a, for example, in the front-rear direction X, the width direction Y, and the vertical direction Z. The hand drive part 5b rotates the hand 5a, for example, within a horizontal plane.

[0092] Processing block 7 includes a transfer mechanism 8. The transfer mechanism 8 transfers the substrate W. The transfer mechanism 8 and the transfer mechanism 5 can mutually transfer the substrate W. The transfer mechanism 8 includes a hand 8a and a hand drive unit 8b. The hand 8a supports the substrate W. The hand drive unit 8b is connected to the hand 8a. The hand drive unit 8b moves the hand 8a. The hand drive unit 8b moves the hand 8a in, for example, the front-rear direction X, the width direction Y, and the vertical direction Z. The hand drive unit 8b rotates the hand 8a in, for example, a horizontal plane.

[0093] Processing block 7 includes a plurality of processing units 11. The processing units 11 are arranged on the side of the transfer mechanism 8. Each processing unit 11 performs processing on the substrate W.

[0094] The processing unit 11 includes a substrate holding part 13. The substrate holding part 13 holds the substrate W.

[0095] The transfer mechanism 8 can access each processing unit 11. The transfer mechanism 8 can deliver the substrate W to the substrate holding part 13. The transfer mechanism 8 can pick up the substrate W from the substrate holding part 13.

[0096] FIG. 3 is a control block diagram of the substrate processing apparatus 1. The substrate processing apparatus 1 includes a control unit 10. The control unit 10 can communicate with the transfer mechanisms 5 and 8 and the processing units 11. The control unit 10 controls the transfer mechanisms 5 and 8 and the processing units 11.

[0097] The control unit 10 is realized by a central processing unit (CPU) that executes various processes, a RAM (Random-Access Memory) that serves as a work area for arithmetic processing, a storage medium such as a fixed disk, and the like. The control unit 10 has various types of information stored in advance in the storage medium. The information possessed by the control unit 10 is, for example, transfer condition information for controlling the transfer mechanisms 5 and 8. The information possessed by the control unit 10 is, for example, processing condition information for controlling the processing units 11. The processing condition information is also called a processing recipe.

[0098] The operation example of the substrate processing apparatus 1 will be briefly described.

[0099] The indexer unit 3 supplies the substrate W to the processing block 7. Specifically, the transfer mechanism 5 passes the substrate W from the carrier C to the transfer mechanism 8 of the processing block 7.

[0100] The transfer mechanism 8 distributes the substrate W to the processing units 11. Specifically, the transfer mechanism 8 transfers the substrate W from the transfer mechanism 5 to the substrate holding portion 13 of each processing unit 11.

[0101] The processing unit 11 processes the substrate W held by the substrate holding portion 13. The processing unit 11 performs, for example, a drying process on the substrate W.

[0102] After the processing unit 11 processes the substrate W, the transfer mechanism 8 recovers the substrate W from each processing unit 11. Specifically, the transfer mechanism 8 receives the substrate W from each substrate holding portion 13. Then, the transfer mechanism 8 passes the substrate W to the transfer mechanism 5.

[0103] The indexer unit 3 recovers the substrate W from the processing block 7. Specifically, the transfer mechanism 5 transfers the substrate W from the transfer mechanism 8 to the carrier C.

[0104] <4. Configuration of the processing unit 11> FIG. 4 is a diagram showing the configuration of the processing unit 11. Each processing unit 11 has the same structure. The processing unit 11 is classified as a single-sheet type. That is, each processing unit 11 processes only one substrate W at a time.

[0105] The processing unit 11 includes a housing 12. The housing 12 has a substantially box shape. The substrate W is processed inside the housing 12.

[0106] The inside of the housing 12 is maintained at a normal temperature. Therefore, the substrate W is processed in an environment of normal temperature.

[0107] The inside of the housing 12 is maintained at normal pressure. Therefore, the substrate W is processed in an environment of normal pressure.

[0108] Here, normal pressure includes standard atmospheric pressure (1 atmosphere, 101325 Pa). Normal pressure is, for example, a pressure within the range of 0.7 atmosphere or more and 1.3 atmosphere or less. In this specification, the pressure value is indicated as absolute pressure based on absolute vacuum.

[0109] The substrate holding unit 13 described above is installed inside the housing 12. The substrate holding unit 13 holds one substrate W. The substrate holding unit 13 holds the substrate W in a substantially horizontal posture.

[0110] The substrate holding unit 13 is located below the substrate W held by the substrate holding unit 13. The substrate holding unit 13 contacts at least either the lower surface of the substrate W or the peripheral edge of the substrate W. The substrate holding unit 13 does not contact the upper surface of the substrate W.

[0111] The processing unit 11 includes a rotation driving unit 14. At least a part of the rotation driving unit 14 is installed inside the housing 12. The rotation driving unit 14 is connected to the substrate holding unit 13. The rotation driving unit 14 rotates the substrate holding unit 13. The substrate W held by the substrate holding unit 13 rotates integrally with the substrate holding unit 13. The substrate W held by the substrate holding unit 13 rotates around the rotation axis B. The rotation axis B, for example, passes through the center of the substrate W and extends in the vertical direction Z.

[0112] The processing unit 11 includes a supply unit 15. The supply unit 15 supplies a liquid or a gas to the substrate W held by the substrate holding unit 13. Specifically, the supply unit 15 supplies a liquid or a gas to the upper surface of the substrate W held by the substrate holding unit 13.

[0113] The supply unit 15 includes a first supply unit 15a, a second supply unit 15b, a third supply unit 15c, a fourth supply unit 15d, and a fifth supply unit 15e. The first supply unit 15a supplies a processing liquid. The second supply unit 15b supplies a chemical solution. The third supply unit 15c supplies a rinse liquid. The fourth supply unit 15d supplies a replacement liquid. The fifth supply unit 15e supplies a drying gas.

[0114] The first supply unit 15a is an example of the processing liquid supply unit in the present invention.

[0115] As described above, the inside of the housing 12 is at normal temperature and normal pressure. Therefore, the processing liquid is used under an environment of normal temperature. The processing liquid is used under an environment of normal pressure.

[0116] The chemical solution supplied by the second supply unit 15b is, for example, an etching solution. The etching solution contains, for example, at least one of hydrofluoric acid (HF) and buffered hydrofluoric acid (BHF).

[0117] The rinse liquid supplied by the third supply unit 15c is, for example, deionized water (DIW).

[0118] The replacement liquid supplied by the fourth supply unit 15d is, for example, an organic solvent. The replacement liquid is, for example, isopropyl alcohol (IPA).

[0119] The drying gas supplied by the fifth supply unit 15e preferably has a dew point lower than normal temperature. The drying gas is, for example, at least one of air and an inert gas. The air is, for example, compressed air. The inert gas is, for example, nitrogen gas.

[0120] The first supply unit 15a includes a nozzle 16a. Similarly, the second to fifth supply units 15b - 15e each include nozzles 16b - 16e. The nozzles 16a - 16e are each installed inside the housing 12. The nozzle 16a discharges the processing liquid. The nozzle 16b discharges the chemical solution. The nozzle 16c discharges the rinse liquid. The nozzle 16d discharges the replacement liquid. The nozzle 16e discharges the drying gas.

[0121] The first supply unit 15a includes a pipe 17a and a valve 18a. The pipe 17a is connected to the nozzle 16a. The valve 18a is provided in the pipe 17a. When the valve 18a opens, the nozzle 16a discharges the processing liquid. When the valve 18a closes, the nozzle 16a does not discharge the processing liquid. Similarly, the second to fifth supply units 15b - 15e each include a pipe 17b - 17e and a valve 18b - 18e. The pipes 17b - 17e are each connected to the nozzles 16b - 16e. The valves 18b - 18e are each provided in the pipes 17b - 17e. The valves 18b - 18e each control the discharge of the chemical solution, the rinse liquid, the replacement liquid, and the drying gas.

[0122] At least a part of the pipe 17a may be provided outside the housing 12. The pipes 17b - 17e may be arranged in the same manner as the pipe 17a. The valve 18a may be provided outside the housing 12. The valves 18b - 18e may be arranged in the same manner as the valve 18a.

[0123] The substrate processing apparatus 1 includes a first supply source 19a. The first supply source 19a is communicatively connected to the first supply unit 15a. The first supply source 19a is connected to, for example, the pipe 17a. The first supply source 19a sends the processing liquid to the first supply unit 15a.

[0124] The second supply unit 15b is communicatively connected to a second supply source 19b. The second supply source 19b is connected to, for example, the pipe 17b. The second supply source 19b sends the chemical solution to the second supply unit 15b. Similarly, the third to fifth supply units 15c - 15e are each communicatively connected to third to fifth supply sources 19c - 19e. The third to fifth supply sources 19c - 19e are each connected to, for example, the pipes 17c - 17e. The third supply source 19c sends the rinse liquid to the third supply unit 15c. The fourth supply source 19d sends the replacement liquid to the fourth supply unit 15d. The fifth supply source 19e sends the drying gas to the fifth supply unit 15e.

[0125] The first supply source 19a is provided outside the housing 12. Similarly, the second to fifth supply sources 19b - 19e are each provided outside the housing 12.

[0126] The first supply source 19a may supply the processing liquid to a plurality of processing units 11. Alternatively, the first supply source 19a may supply the processing liquid to only one processing unit 11. The same applies to the second to fifth supply sources 19b - 19e.

[0127] The second supply source 19b may be an element of the substrate processing apparatus 1. For example, the second supply source 19b may be a chemical liquid tank provided in the substrate processing apparatus 1. Alternatively, the second supply source 19b may not be an element of the substrate processing apparatus 1. For example, the second supply source 19b may be a utility facility installed outside the substrate processing apparatus 1. Similarly, each of the third to fifth supply sources 19c - 19e may be an element of the substrate processing apparatus 1. Alternatively, each of the third to fifth supply sources 19c - 19e may not be an element of the substrate processing apparatus 1.

[0128] The processing unit 11 may further include a cup (not shown). The cup is installed inside the housing 12. The cup is disposed around the substrate holding portion 13. The cup receives the liquid scattered from the substrate W held by the substrate holding portion 13.

[0129] Referring to FIG. 3, the control unit 10 controls the rotation drive unit 14. The control unit 10 controls the supply unit 15. The control unit 10 controls the valves 18a - 18e.

[0130] <5. Configuration of the First Supply Source 19a> Referring to FIG. 4, the first supply source 19a further generates a processing liquid.

[0131] An example of the configuration of the first supply source 19a is illustrated. The first supply source 19a is divided into a generation unit 21 and a pressure feeding unit 31. The generation unit 21 generates the processing liquid. The pressure feeding unit 31 sends the processing liquid to the first supply unit 15a.

[0132] The generating unit 21 includes a tank 22 and supply parts 23a and 23b. The supply part 23a supplies a sublimable substance to the tank 22. The supply part 23b supplies a solvent to the tank 22. The sublimable substance and the solvent are mixed in the tank 22. The sublimable substance and the solvent become a treatment liquid g in the tank 22.

[0133] The tank 22 is installed under a normal temperature environment. The tank 22 is installed under a normal pressure environment. Therefore, the treatment liquid g is generated under a normal temperature environment. The treatment liquid g is generated under a normal pressure environment.

[0134] Furthermore, the generating unit 21 stores the treatment liquid g. Specifically, the treatment liquid g is stored in the tank 22. The treatment liquid g is stored under a normal temperature environment. The treatment liquid g is stored under a normal pressure environment.

[0135] The supply part 23a includes, for example, a pipe 24a and a valve 25a. The pipe 24a is communicatively connected to the tank 22. The valve 25a is provided in the pipe 24a. When the valve 25a opens, the supply part 23a supplies the sublimable substance to the tank 22. When the valve 25a closes, the supply part 23a does not supply the sublimable substance to the tank 22. Similarly, the supply part 23b includes a pipe 24b and a valve 25b. The pipe 24b is communicatively connected to the tank 22. The valve 25b is provided in the pipe 24b. The valve 25b controls the supply of the solvent to the tank 22.

[0136] Furthermore, the valve 25a adjusts the amount of the sublimable substance supplied to the tank 22. The valve 25b adjusts the amount of the solvent supplied to the tank 22.

[0137] Each of the valves 25a and 25b may include, for example, a flow rate regulating valve. Each of the valves 25a and 25b may include, for example, a flow rate regulating valve and an on-off valve.

[0138] The supply unit 23a is communicatively connected to the supply source 26a. For example, the supply source 26a is connected to the pipe 24a. The supply source 26a sends the sublimable substance to the supply unit 23a. Similarly, the supply unit 23b is communicatively connected to the supply source 26b. For example, the supply source 26b is connected to the pipe 24b. The supply source 26b sends the solvent to the supply unit 23b.

[0139] Here, let the volume of the sublimable substance for generating the processing liquid g be the volume Q1g. More specifically, the volume Q1g is the volume of the sublimable substance used for generating the processing liquid g. Let the volume of the solvent for generating the processing liquid g be the volume Q2g. More specifically, the volume Q2g is the volume of the solvent used for generating the processing liquid g. The ratio of the volume Q2g to the volume Q1g is called the mixing ratio R of the processing liquid g, or simply the mixing ratio R. Specifically, the mixing ratio R is defined by the following formula. Mixing ratio R = (volume Q1g) / (volume Q2g) * 100 (Vol%)

[0140] The mixing ratio R is limited to be equal to or less than the solubility Rm described above. The solubility Rm corresponds to the upper limit value of the mixing ratio R.

[0141] The mixing ratio R substantially determines the concentration V of the sublimable substance in the processing liquid g. Hereinafter, the concentration V of the sublimable substance in the processing liquid g is called the concentration V of the processing liquid g, or simply the concentration V. Strictly speaking, the mixing ratio R substantially determines the initial concentration V0. The initial concentration is the concentration V of the processing liquid g before the processing liquid g is supplied to the substrate W.

[0142] The volume Q1g is adjusted by the valve 25a. The volume Q2g is adjusted by the valve 25b. The mixing ratio R is adjusted by the valves 25a and 25b. The initial concentration V0 is substantially adjusted by the valves 25a and 25b.

[0143] The pressure feeding unit 31 includes a pipe 32 and a joint 33. The pipe 32 is communicatively connected to the tank 22. The joint 33 is connected to the pipe 32. The joint 33 is further connected to the pipe 17a. The pipe 32 is communicatively connected to the pipe 17a by the joint 33. Therefore, the tank 22 is communicatively connected to the first supply unit 15a via the pipe 32 and the joint 33. The tank 22 is communicatively connected to the nozzle 16a.

[0144] The pressure feeding unit 31 further includes a pump 34 and a filter 35. The pump 34 is provided in the pipe 32. When the pump 34 operates, the pump 34 pumps the processing liquid g from the tank 22 to the first supply unit 15a. When the pump 34 stops operating, the pump 34 does not pump the processing liquid g from the tank 22 to the first supply unit 15a. The filter 35 is provided in the pipe 32. The processing liquid g passes through the filter 35. The filter 35 filters the processing liquid g. The filter 35 removes foreign matters from the processing liquid g.

[0145] Refer to FIG. 3. The control unit 10 is communicable with the first supply source 19a. The control unit 10 controls the first supply source 19a. The control unit 10 controls the generation unit 21. The control unit 10 controls the supply units 23a and 23b. The control unit 10 controls the valves 25a and 25b. The control unit 10 controls the pressure feeding unit 31. The control unit 10 controls the pump 34.

[0146] The control unit 10 has processing liquid condition information for controlling the first supply source 19a. The processing liquid condition information includes information regarding the conditions of the processing liquid. The processing liquid condition information includes, for example, a target regarding the mixing ratio R. The target regarding the mixing ratio may be defined by one value. The target regarding the mixing ratio may be defined by a range between two different values. The processing liquid condition information is pre-stored in the storage medium of the control unit 10.

[0147] <6. Operating Examples of the First Supply Source 19a and the Processing Unit 11> 5 is a flowchart showing the steps of a substrate processing method according to an embodiment. The substrate processing method includes step S1 and steps S11-S18. Step S1 is performed by first supply source 19a. Steps S11-S18 are substantially performed by processing unit 11. Step S1 is performed in parallel with steps S11-S18. First supply source 19a and processing unit 11 operate under the control of control unit 10.

[0148] Each of steps S1, S11 to S18 will be described with reference to FIG. 4 as needed.

[0149] Step S1: Processing liquid generation process In the processing liquid generating step, processing liquid g is generated.

[0150] The control unit 10 controls the generation unit 21 based on the processing liquid condition information. The generation unit 21 generates the processing liquid g. Specifically, the control unit 10 controls the supply units 23a and 23b based on a target for the blending ratio R. The supply unit 23a supplies a sublimable substance to the tank 22. The supply unit 23b supplies a solvent to the tank 22. The processing liquid g is generated in the tank 22. The processing liquid g has a blending ratio R that meets the target for the blending ratio R. The processing liquid g is stored in the tank 22.

[0151] Step S11: Rotation start process The substrate holder 13 holds the substrate W. The substrate W is held in a substantially horizontal position. The rotation driver 14 rotates the substrate holder 13. As a result, the substrate W held by the substrate holder 13 starts to rotate.

[0152] In steps S12-S17 described below, the substrate W continues to rotate, for example.

[0153] Step S12: Chemical solution supply process In the chemical liquid supplying step, the chemical liquid is supplied to the substrate W.

[0154] The second supply unit 15b supplies a chemical solution to the substrate W held by the substrate holding unit 13. Specifically, the valve 18b opens. The nozzle 16b discharges the chemical solution. The chemical solution is supplied to the upper surface of the substrate W. For example, the chemical solution etches the substrate W. For example, the chemical solution removes the natural oxide film from the substrate W.

[0155] After that, the second supply unit 15b stops supplying the chemical solution to the substrate W. Specifically, the valve 18b closes. The nozzle 16b stops discharging the chemical solution.

[0156] Step S13: Rinse liquid supply process In the rinse liquid supply process, a rinse liquid is supplied to the substrate W.

[0157] The third supply unit 15c supplies a rinse liquid to the substrate W held by the substrate holding unit 13. Specifically, the valve 18c opens. The nozzle 16c discharges the rinse liquid. The rinse liquid is supplied to the upper surface of the substrate W. For example, the rinse liquid cleans the substrate W. For example, the rinse liquid removes the chemical solution from the substrate W.

[0158] After that, the third supply unit 15c stops supplying the rinse liquid to the substrate W. Specifically, the valve 18c closes. The nozzle 16c stops discharging the rinse liquid.

[0159] Step S14: Replacement liquid supply process In the replacement liquid supply process, a replacement liquid is supplied to the substrate W.

[0160] The fourth supply unit 15d supplies a replacement liquid to the substrate W held by the substrate holding unit 13. Specifically, the valve 18d opens. The nozzle 16d discharges the replacement liquid. The replacement liquid is supplied to the upper surface of the substrate W. The replacement liquid removes the rinse liquid from the substrate W. The rinse liquid on the substrate W is replaced with the replacement liquid.

[0161] After that, the fourth supply unit 15d stops supplying the replacement liquid to the substrate W. Specifically, the valve 18d closes. The nozzle 16d stops discharging the replacement liquid.

[0162] Step S15: Processing Liquid Supply Step In the processing liquid supply step, the processing liquid g is supplied to the substrate W.

[0163] The pressure feeding unit 31 supplies the processing liquid g to the first supply unit 15a. The first supply unit 15a supplies the processing liquid g to the substrate W held by the substrate holding unit 13. Specifically, the pump 34 pressure-feeds the processing liquid g from the tank 22 to the first supply unit 15a. The valve 18a opens. The nozzle 16a discharges the processing liquid g. The processing liquid g is supplied to the upper surface of the substrate W. The processing liquid g removes the replacement liquid from the substrate W. The replacement liquid on the substrate W is replaced with the processing liquid g.

[0164] Thereafter, the pressure feeding unit 31 stops the supply of the processing liquid g to the first supply unit 15a. The first supply unit 15a stops the supply of the processing liquid g to the substrate W. Specifically, the pump 34 stops. The valve 18a closes. The nozzle 16a stops discharging the processing liquid g.

[0165] FIG. 6 is a diagram schematically showing the substrate W in the processing liquid supply step. When the substrate W is held by the substrate holding unit 13, the pattern WP is located on the upper surface of the substrate W. When the substrate W is held by the substrate holding unit 13, the pattern WP faces upward.

[0166] The processing liquid g on the substrate W forms a liquid film G. The liquid film G is located on the substrate W. The liquid film G is in contact with the substrate W. The liquid film G covers the substrate W. The liquid film G covers the upper surface of the substrate W.

[0167] All of the pattern WP is immersed in the liquid film G. All of the convex portions W1 are immersed in the liquid film G. The concave portion A is filled with the liquid film G. All of the concave portion A is filled only with the liquid film G.

[0168] The liquid film G has an upper surface G1. The upper surface G1 is located at a position higher than all of the pattern WP. The upper surface G1 does not intersect with the pattern WP. The upper surface G1 is located at a position higher than all of the convex portions W1. The upper surface G1 does not intersect with the convex portions W1.

[0169] The replacement liquid has already been removed from the substrate W by the treatment liquid g. Therefore, the replacement liquid does not exist on the substrate W. The replacement liquid does not remain in the concave portion A.

[0170] The gas J exists above the liquid film G. The pattern WP does not contact the gas J. The pattern WP is not exposed to the gas J. The convex portion W1 does not contact the gas J. The convex portion W1 is not exposed to the gas J.

[0171] The gas J contacts the liquid film G. The gas J contacts the upper surface G1. The upper surface G1 corresponds to the gas-liquid interface between the liquid film G and the gas J. Therefore, the pattern WP does not intersect the gas-liquid interface between the liquid film G and the gas J. The convex portion W1 does not intersect the gas-liquid interface between the liquid film G and the gas J.

[0172] In the treatment liquid supply step, the height position of the upper surface G1 may be further adjusted. For example, while the nozzle 16a supplies the treatment liquid g to the substrate W, the height position of the upper surface G1 may be adjusted. For example, after the nozzle 16a stops supplying the treatment liquid g, the height position of the upper surface G1 may be adjusted. For example, by adjusting the rotation speed of the substrate W, the height position of the upper surface G1 may be adjusted. For example, by adjusting the rotation time of the substrate W, the height position of the upper surface G1 may be adjusted.

[0173] Here, adjusting the height position of the upper surface G1 corresponds to adjusting the thickness HG of the liquid film G. The thickness HG of the liquid film G is, for example, the distance in the vertical direction Z between the base end W1p of the convex portion W1 and the upper surface G1.

[0174] Step S16: Solidified film formation step In the solidified film formation step, the solvent evaporates from the treatment liquid g on the substrate W. In the solidified film formation step, a solidified film is formed on the substrate W. The solidified film contains a sublimable substance.

[0175] FIG. 7 is a diagram schematically showing a substrate W in the solidified film forming step. As described above, the solvent has a relatively high vapor pressure. At normal temperature, the solvent has a higher vapor pressure than the sublimable substance. Therefore, the solvent smoothly evaporates from the treatment liquid g on the substrate W. The solvent smoothly changes from a liquid to a gas.

[0176] When the solvent evaporates from the treatment liquid g on the substrate W, the solvent leaves the treatment liquid g on the substrate W. As the solvent evaporates from the treatment liquid g on the substrate W, the amount of the solvent contained in the liquid film G decreases. As the amount of the solvent contained in the liquid film G decreases, the concentration V of the sublimable substance in the liquid film G increases.

[0177] Eventually, the sublimable substance in the liquid film G begins to precipitate on the substrate W. That is, the sublimable substance changes from the solute of the treatment liquid g to the solid-phase sublimable substance. The solid-phase sublimable substance forms a solidified film K. The solidified film K does not contain a solvent. The solidified film K is solid. The solidified film K is formed on the substrate W.

[0178] Due to the evaporation of the solvent and the precipitation of the sublimable substance, the liquid film G gradually decreases. Due to the precipitation of the sublimable substance, the liquid film G gradually changes into the solidified film K. Due to the precipitation of the sublimable substance, the solidified film K gradually increases. The solidified film K gradually grows.

[0179] First, the upper part of the liquid film G changes into the solidified film K. The solidified film K is located above the liquid film G. The solidified film K covers the upper surface G1 of the liquid film G.

[0180] When the solidified film K covers the entire upper surface G1, the solidified film K separates the liquid film G from the gas J. The liquid film G is in contact with the solidified film K. The upper surface G1 of the liquid film G is in contact with the solidified film K. The liquid film G is not in contact with the gas J. The upper surface G1 is not in contact with the gas J. The gas-liquid interface between the liquid film G and the gas J disappears. The gas J is in contact with the solidified film K. The gas J is in contact with the upper surface K1 of the solidified film K.

[0181] Therefore, the pattern WP does not intersect with the gas-liquid interface. The liquid film G does not exert a significant force on the pattern WP. The convex portion W1 does not intersect with the gas-liquid interface. The liquid film G does not exert a significant force on the convex portion W1.

[0182] The solidified film K has a thickness HK. The thickness HK of the solidified film K is, for example, the distance in the vertical direction Z between the upper surface G1 of the liquid film G and the upper surface K1 of the solidified film K.

[0183] As the solidified film K increases, the liquid film G decreases. As the thickness HK of the solidified film K increases, the thickness HG of the liquid film G decreases. As the thickness HK of the solidified film K increases, the height position of the upper surface G1 becomes lower. Without the liquid film G exerting a significant force on the convex portion W1, the liquid film G gradually decreases. Without the solvent exerting a significant force on the convex portion W1, the solvent gradually leaves the substrate W.

[0184] FIG. 8 is a diagram schematically showing the substrate W in the solidified film forming step. FIG. 8 schematically shows the substrate W, for example, at the end of the solidified film forming step. Only the solidified film K exists on the substrate W. At the end of the solidified film forming step, all of the liquid film G disappears from the substrate W. The liquid film G does not remain in the concave portion A. All of the solvent disappears from the substrate W. The solvent also does not remain in the concave portion A.

[0185] The solidified film K extends to the proximal end W1p of the substrate W. The concave portion A is filled with the solidified film K. All of the concave portion A is filled only with the solidified film K. After all of the liquid film G has disappeared from the substrate W, the thickness HK of the solidified film K is, for example, the distance in the vertical direction Z between the proximal end W1p of the convex portion W1 and the upper surface K1 of the solidified film K.

[0186] The pattern WP is in contact with the solidified film K. The solidified film K supports the pattern WP. The solidified film K protects the pattern WP. For example, the solidified film K prevents the pattern WP from collapsing. The convex portion W1 is in contact with the solidified film K. The solidified film K supports the convex portion W1. The solidified film K protects the convex portion W1. For example, the solidified film K prevents the convex portion W1 from collapsing.

[0187] Step S17: Sublimation process In the sublimation process, the solidified film K sublimates.

[0188] The fifth supply unit 15e supplies dry gas to the substrate W held by the substrate holding unit 13. Specifically, the valve 18e opens. The nozzle 16e discharges dry gas. The nozzle 16e blows dry gas onto the substrate W. The dry gas is supplied to the upper surface of the substrate W. The dry gas is supplied to the solidified film K. The solidified film K is exposed to the dry gas. As a result, the solidified film K sublimates. The solidified film K changes to a gas without going through a liquid state. Due to the sublimation of the solidified film K, the solidified film K is removed from the substrate W.

[0189] After that, the fifth supply unit 15e stops supplying dry gas to the solidified film K. Specifically, the valve 18e closes. The nozzle 16e stops blowing out dry gas.

[0190] FIG. 9 is a diagram schematically showing the substrate W in the sublimation process. As the solidified film K sublimates, the solidified film K gradually decreases. As the solidified film K sublimates, the height position of the upper surface K1 of the solidified film K becomes lower. As the solidified film K sublimates, the thickness HK of the solidified film K gradually decreases. As the solidified film K sublimates, the solidified film K gradually becomes thinner.

[0191] Note that the sublimable substance has sublimability. Therefore, the sublimation of the solidified film K may start before the liquid film G disappears from the substrate W. A part of the period during which the sublimation process is executed may overlap with a part of the period during which the solidified film forming process is executed.

[0192] The pattern WP begins to be exposed to the gas J. The convex portion W1 begins to be exposed to the gas J.

[0193] When the solidified film K sublimates, the solidified film K does not change to a liquid. Therefore, in the sublimation process, no liquid exists on the substrate W. In the sublimation process, no liquid exists in the concave portion A. In the sublimation process, no gas-liquid interface is generated in the vicinity of the pattern WP.

[0194] Therefore, the pattern WP does not intersect with the gas-liquid interface. The solidified film K does not exert a significant force on the pattern WP. Without the solidified film K exerting a significant force on the pattern WP, the solidified film K detaches from the substrate W. The convex portion W1 does not intersect with the gas-liquid interface. The solidified film K does not exert a significant force on the convex portion W1. Without the solidified film K exerting a significant force on the convex portion W1, the solidified film K detaches from the substrate W.

[0195] FIG. 10 is a diagram schematically showing the substrate W in the sublimation process. FIG. 10 schematically shows the substrate W, for example, at the end of the sublimation process. At the end of the sublimation process, all of the solidified film K disappears from above the substrate W. There is no liquid on the substrate W. All of the pattern WP is exposed to the gas. All of the convex portions W1 are exposed to the gas. All of the concave portions A are filled only with the gas J. The substrate W is dried.

[0196] The processes in the above-described treatment liquid supply step, solidified film formation step, and sublimation step are examples of a drying process. The processes in the above-described treatment liquid supply step, solidified film formation step, and sublimation step correspond to examples of the use of the treatment liquid g. The treatment liquid g is used in an environment at normal temperature. The treatment liquid g is used in an environment at normal pressure.

[0197] Step S18: Rotation stop step The rotation drive unit 14 stops the rotation of the substrate holding unit 13. The substrate W held by the substrate holding unit 13 stops rotating. The substrate W becomes stationary. The processing unit 11 finishes the processing on the substrate W.

[0198] <7. Technical significance of the treatment liquid g> The technical significance of the treatment liquid g will be described by Examples 1a-1h, 2a-2h and Comparative Examples 1a-1h, 2a-2h. Hereinafter, Examples 1a-1h will be collectively referred to as Example Group 1. Examples 2a-2h will be collectively referred to as Example Group 2. Comparative Examples 1a-1h will be collectively referred to as Comparative Example Group 1. Comparative Examples 2a-2h will be collectively referred to as Comparative Example Group 2.

[0199] Describe the conditions of Example Group 1. The difference among Examples 1a - 1h is only the mixing ratio R. Conditions other than the mixing ratio R are common among Examples 1a - 1h.

[0200] Specifically, in Examples 1a - 1h, the substrate W is processed in the treatment liquid supply step, the solidification film formation step, and the sublimation step. More specifically, in Examples 1a - 1h, the substrate W is processed in the chemical solution supply step, the rinse liquid supply step, the replacement liquid supply step, the treatment liquid supply step, the solidification film formation step, and the sublimation step.

[0201] The chemical solution used in the chemical solution supply step is hydrofluoric acid. Hydrofluoric acid is a mixed solution of hydrogen fluoride and water. The volume ratio of hydrogen fluoride to water is as follows. Hydrogen fluoride:Water = 1:10 (volume ratio)

[0202] The rinse liquid used in the rinse liquid supply step is deionized water (DIW).

[0203] The replacement liquid used in the replacement liquid supply step is isopropyl alcohol.

[0204] The treatment liquid g used in the treatment liquid supply step consists of a sublimable substance and a solvent. The sublimable substance is 4 - tert - butylphenol. The solvent is isopropyl alcohol (IPA).

[0205] The mixing ratio R of Example 1a is 2.5 Vol%. When the mixing ratio R is 2.5 vol%, the following equation holds. Volume Q1g:Volume Q2g = 1:40 The mixing ratios R of Examples 1b, 1c, 1d, 1e, 1f, 1g, 1h are 5.0, 6.7, 10.0, 12.5, 16.7, 20.0, 25.0 Vol% respectively.

[0206] In the solidification film formation step, the substrate W is rotated at a rotational speed of 1500 rpm.

[0207] In the sublimation step, while rotating the substrate W at a rotational speed of 1500 rpm, a drying gas is supplied to the substrate W.

[0208] The conditions of Example Group 2 and Comparative Example Groups 1 and 2 are described. In Example Group 2, the sublimable substance is acetophenone oxime. In Comparative Example Group 1, the sublimable substance is cyclohexanone oxime. In Comparative Example Group 2, the sublimable substance is pinacolin oxime.

[0209] The conditions other than the sublimable substance are common among Example 1a, 2a and Comparative Examples 1a, 2b. The conditions other than the sublimable substance are common among Example 1b, 2b and Comparative Example 1b, 2b. The conditions other than the sublimable substance are common among Example 1c, 2c and Comparative Example 1c, 2c. The conditions other than the sublimable substance are common among Example 1d, 2d and Comparative Example 1d, 2d. The conditions other than the sublimable substance are common among Example 1e, 2e and Comparative Example 1e, 2e. The conditions other than the sublimable substance are common among Example 1f, 2f and Comparative Example 1f, 2f. The conditions other than the sublimable substance are common among Example 1g, 2g and Comparative Example 1g, 2g. The conditions other than the sublimable substance are common among Example 1h, 2h and Comparative Example 1h, 2h.

[0210] Each substrate W processed in Examples 1a - 1h, 2a - 2h and Comparative Examples 1a - 1h, 2a - 2h was evaluated by the collapse rate D (%). The collapse rate D is the probability that the pattern WP on the substrate W collapses when the substrate W is processed. In other words, the collapse rate D is the probability that the convex portion W1 on the substrate W collapses when the substrate W is processed. A small collapse rate D means that the pattern WP is protected.

[0211] Illustrate the collapse rate D. The collapse rate D is, for example, the median dm (%) among a plurality of local collapse rates di. The median dm is one local collapse rate di located in the center in a sequence in which all local collapse rates di are arranged in ascending order of magnitude. Each local collapse rate di (%) is the collapse rate in each local area Ei. i is an arbitrary natural number from 1 to NE. NE is the number of local areas Ei. The number NE is a natural number of 2 or more. Each local area Ei is a minute area of the substrate W. Each local area Ei is magnified 50,000 times by, for example, a scanning electron microscope. An observer observes the pattern WP (protrusion W1) in each local area Ei. The observer determines each protrusion W1 in each local area Ei one by one. Specifically, the observer determines whether or not the protrusion W1 has collapsed for each protrusion W1. Here, let the number of protrusions W1 determined in each local area Ei be NPi. Let the number of protrusions W1 determined to have collapsed in each local area Ei be NTi. The number NTi is less than or equal to the number NPi. The local collapse rate di is the ratio of the number NTi to the number NPi. The local collapse rate di is defined, for example, by the following formula. di = NTi / NPi * 100 (%)

[0212] Furthermore, in Examples 1a - 1h, 2a - 2h and Comparative Examples 1a - 1h, 2a - 2h, the maximum height HM of the solidified film K was measured. The maximum height HM of the solidified film K is, for example, the distance in the vertical direction Z between the base end W1p of the protrusion W1 and the upper surface K1 of the solidified film K when the liquid film G starts to change into the solidified film K. The maximum height HM of the solidified film K is substantially equal to the thickness HG of the liquid film G immediately before the liquid film G changes into the solidified film K. For reference, FIG. 7 shows the maximum height HM. The maximum height HM of the solidified film K can also be said to be the initial height of the solidified film K. More specifically, the maximum height HM of the solidified film K can also be said to be the height of the solidified film K at the initial stage when the solidified film K starts to be formed. The maximum height HM is, for example, the maximum value of the distance in the vertical direction Z between the base end W1p of the protrusion W1 and the upper surface K1 of the solidified film K.

[0213] The maximum height HM of the solidified film K was measured using a film thickness gauge. The film thickness gauge is, for example, an optical interference film thickness gauge. The optical interference film thickness gauge detects interference light reflected from the liquid film G or the solidified film K, and obtains a measured value of the film thickness HG or the film thickness HK based on the detected interference light. The interference light includes the light reflected from the surface of the liquid film G or the solidified film K and the light reflected from the back surface of the liquid film G or the solidified film K.

[0214] Here, the liquid film G has a relatively high transparency. The liquid film G reflects light appropriately. Therefore, the thickness HG of the liquid film G is appropriately measured by the film thickness gauge. In contrast, the solidified film K has a lower transparency than the liquid film G. The solidified film K does not reflect light appropriately. Therefore, the film thickness HK of the solidified film K is not appropriately measured by the film thickness gauge. Thus, when changing from the liquid film G to the solidified film K, the measured value of the film thickness gauge changes greatly.

[0215] Therefore, the maximum height HM of the solidified film K was estimated by the following method. The film thickness gauge continuously measures the liquid film G and the solidified film K on the substrate W from the treatment liquid supply step to the solidified film formation step. From the measurement results of the film thickness gauge, one measurement value immediately before the measured value changes greatly over time is specified as the transition measurement value. The transition measurement value is regarded as the thickness HG of the liquid film G immediately before the liquid film G changes to the solidified film K. Further, the transition measurement value is regarded as the maximum height HM of the solidified film K.

[0216] FIG. 11 is a table showing the collapse rate D of each substrate W processed in Example Group 1. FIG. 12 is a table showing the collapse rate D of each substrate W processed in Example Group 2. FIG. 13 is a table showing the collapse rate D of each substrate W processed in Comparative Example Group 1. FIG. 14 is a table showing the collapse rate D of each substrate W processed in Comparative Example Group 2. FIG. 15 is a graph showing the relationship between the blending ratio R and the collapse rate D in Example Groups 1 and 2 and Comparative Example Groups 1 and 2. In FIGS. 11-14, a collapse rate of 20% or less is indicated in gray tone. In the graph of FIG. 15, the horizontal axis is the blending ratio R, and the vertical axis is the collapse rate D.

[0217] Refer to Fig. 11. In Example Group 1, when the mixing ratio R changes, the collapse rate D changes. By changing the mixing ratio R, a plurality of collapse rates D can be obtained. In other words, at different mixing ratios R, a plurality of collapse rates D can be obtained. Among the plurality of collapse rates D, the smallest collapse rate D is called the minimum collapse rate Da. The minimum collapse rate Da of Example Group 1 is 5.00% or less. The minimum collapse rate Da of Example Group 1 is 1.00% or less. Specifically, the minimum collapse rate Da of Example Group 1 is 0.19%.

[0218] The mixing ratio R when the collapse rate D is the minimum collapse rate Da is called the optimal mixing ratio Ra. The optimal mixing ratio Ra of Example Group 1 is 10 vol%.

[0219] Refer to Fig. 12. In Example Group 2, by changing the mixing ratio R, a plurality of collapse rates D can be obtained. The minimum collapse rate Da of Example Group 2 is 5.00% or less. The minimum collapse rate Da of Example Group 2 is 1.00% or less. Specifically, the minimum collapse rate Da of Example Group 2 is 0.66%. The optimal mixing ratio Ra of Example Group 2 is 6.7 vol%.

[0220] Refer to Fig. 13. In Comparative Example Group 1, by changing the mixing ratio R, a plurality of collapse rates D can be obtained. The minimum collapse rate Da of Comparative Example Group 1 is 0.05%. The optimal mixing ratio Ra of Comparative Example Group 1 is 6.7 vol%.

[0221] Refer to Fig. 14. In Comparative Example Group 2, by changing the mixing ratio R, a plurality of collapse rates D can be obtained. The minimum collapse rate Da of Comparative Example Group 2 is 15.12%. The optimal mixing ratio Ra of Comparative Example Group 2 is 6.7 vol%.

[0222] Refer to Figs. 11 - 14. In Example Group 1, as the mixing ratio R increases from 2.5 vol% to the optimal mixing ratio Ra, the collapse rate D decreases. In Example Group 1, as the mixing ratio R increases from the optimal mixing ratio Ra to 25 vol%, the collapse rate D increases. Example Group 2 and Comparative Example Groups 1 and 2 also have the same tendency as Example Group 1.

[0223] In FIG. 15, the curve (broken line) of Example Group 1 curves convex downward. Similarly, the curves of Example Group 2 and Comparative Example Groups 1 and 2 each curve convex downward.

[0224] FIG. 16 is a graph showing the relationship between the mixing ratio R and the maximum height HM of the solidified film K in Example Groups 1 and 2 and Comparative Example Groups 1 and 2. In the graph of FIG. 16, the horizontal axis is the mixing ratio R. The vertical axis is the height ratio P (%). Here, the height ratio P is the ratio of the maximum height HM of the solidified film K to the height HP of the pattern WP. Specifically, the height ratio P is defined by the following equation. Height ratio P = HM / HP * 100 (%)

[0225] In Example Group 1, the height ratio P increases in proportion to the mixing ratio R. In Example Group 1, when the mixing ratio is 5 vol%, the height ratio P is less than 100%. In Example Group 1, when the mixing ratio is 10 vol% or more, the height ratio P is greater than 100%. Example Group 2 and Comparative Example Groups 1 and 2 also have the same tendency as Example Group 1.

[0226] In Example Group 1, when the mixing ratio R is 16.7 vol%, the height ratio P is approximately 250%. In Example Group 1, when the mixing ratio R is 20.0 vol%, the height ratio P is approximately 300%. In Example Group 1, when the mixing ratio R is 25.0 vol%, the height ratio P is approximately 350%.

[0227] In Example Group 2, when the mixing ratio R is 20.0 vol%, the height ratio P is approximately 300%. In Example Group 2, when the mixing ratio R is 25.0 vol%, the height ratio P is approximately 400%.

[0228] Regardless of the mixing ratio R, the value of the height HP is constant. For this reason, in Example Group 1, the maximum height HM of the solidified film K increases in proportion to the mixing ratio R. Example Group 2 and Comparative Example Groups 1 and 2 also have the same tendency as Example Group 1.

[0229] FIG. 17 is a table analyzing the collapse rate D of the substrate W processed in Example Groups 1 and 2 and Comparative Example Groups 1 and 2. The optimal mixing ratios Ra of Example Groups 1 and 2 and Comparative Example Groups 1 and 2 are as described above. The minimum collapse rates Da of Example Groups 1 and 2 and Comparative Example Groups 1 and 2 are also as described above.

[0230] FIG. 17 shows the first reference value F1 (%). The first reference value F1 is a value obtained by adding 5% to the minimum collapse rate Da. The first reference value F1 of Example Group 1 is 5.19 vol%. The first reference value F1 of Example Group 2 is 5.66 vol%. The first reference value F1 of Comparative Example Group 1 is 5.05 vol%. The first reference value F1 of Comparative Example Group 2 is 20.12 vol%.

[0231] FIG. 17 shows the lower limit value T1a (vol%) and the upper limit value T1b (vol%). The lower limit value T1a is the minimum value of the mixing ratio R when the collapse rate D is less than or equal to the first reference value F1. The upper limit value T1b is the maximum value of the mixing ratio R when the collapse rate D is less than or equal to the first reference value F1. The lower limit value T1a and the upper limit value T1b define the first range T1. That is, the first range T1 is the range from the lower limit value T1a to the upper limit value T1b. The first range T1 is the range of the mixing ratio R when the collapse rate D is less than or equal to the first reference value F1.

[0232] FIG. 17 shows the width U1. The width U1 is the width of the first range T1. The width U1 is the difference between the lower limit value T1a and the upper limit value T1b.

[0233] Referring to FIGS. 11 and 17, the first range T1 of Example Group 1 will be described. When the mixing ratio R is 5.0 vol%, the collapse rate D is higher than the first reference value F1. When the mixing ratio R is 6.7 vol%, the collapse rate D is lower than the first reference value F1. Therefore, the lower limit value T1a is greater than 5.0 vol% and less than 6.7 vol%. When the mixing ratio R is 16.7 vol%, the collapse rate D is lower than the first reference value F1. When the mixing ratio R is 20.0 vol%, the collapse rate D is higher than the first reference value F1. Therefore, the upper limit value T1b is greater than 16.7 vol% and less than 20.0 vol%. Accordingly, the width U1 of Example Group 1 is greater than 10.0 and less than 15.0.

[0234] Referring to FIGS. 12 and 17, the first range T1 of Example Group 2 will be described. The lower limit value T1a is greater than 5.0 vol% and less than 6.7. The upper limit value T1b is greater than 25.0 vol%. Accordingly, the width U1 of Example Group 2 is greater than 18.3.

[0235] Referring to FIGS. 13 and 17, the first range T1 of Comparative Example Group 1 will be described. The lower limit value T1a is greater than 5.0 vol% and less than 6.7. The upper limit value T1b is greater than 10.0 vol% and less than 12.5 vol%. Accordingly, the width U1 of Comparative Example Group 1 is greater than 3.3 and less than 7.5.

[0236] Referring to FIGS. 14 and 17, the first range T1 of Comparative Example Group 2 will be described. The lower limit value T1a is greater than 5.0 vol% and less than 6.7. The upper limit value T1b is greater than 6.7 vol% and less than 10.0 vol%. Accordingly, the width U1 of Comparative Example Group 2 is greater than 0 and less than 5.

[0237] In FIG. 17, “YES” or “NO” is indicated in the column of “Width U1 > 10?”. “YES” means that the width U1 is 10 or more. “NO” means that the width U1 is less than 10. The width U1 of Example Groups 1 and 2 is “YES” respectively. The width U1 of Comparative Example Groups 1 and 2 is “NO” respectively.

[0238] FIG. 17 shows the lower limit value T2a (vol%) and the upper limit value T2b (vol%). The lower limit value T2a is the minimum value of the mixing ratio R when the collapse rate D is 20% or less. The upper limit value T2b is the maximum value of the mixing ratio R when the collapse rate D is 20% or less. The lower limit value T2a and the upper limit value T2b define the second range T2. That is, the second range T2 is the range from the lower limit value T2a to the upper limit value T2b. The second range T2 is the range of the mixing ratio R when the collapse rate D is 20% or less.

[0239] FIG. 17 shows the width U2. The width U2 is the width of the second range T2. The width U2 is the difference between the lower limit value T2a and the upper limit value T2b.

[0240] Referring to FIGS. 11 and 17, the second range T2 of Example Group 1 will be described. When the mixing ratio R is 5.0 vol%, the collapse rate D is higher than 20%. When the mixing ratio R is 6.7 vol%, the collapse rate D is lower than 20%. Therefore, the lower limit value T2a is larger than 5.0 vol% and smaller than 6.7 vol%. When the mixing ratio R is 25.0 vol%, the collapse rate D is lower than 20%. Therefore, the upper limit value T2b is larger than 25.0 vol%. Accordingly, the width U2 of Example Group 1 is larger than 18.3.

[0241] Referring to FIGS. 12 and 17, the second range T2 of Example Group 2 will be described. The lower limit value T2a is larger than 2.5 vol% and smaller than 5.0. The upper limit value T2b is larger than 25.0 vol%. Accordingly, the width U2 of Example Group 2 is larger than 20.0.

[0242] Referring to FIGS. 13 and 17, the second range T2 of Comparative Example Group 1 will be described. The lower limit value T2a is greater than 2.5 vol% and less than 5.0. The upper limit value T2b is greater than 10.0 vol% and less than 12.5 vol%. Therefore, the width U2 of Comparative Example Group 1 is greater than 5.0 and less than 10.0.

[0243] Referring to FIGS. 14 and 17, the second range T2 of Comparative Example Group 2 will be described. The lower limit value T2a is greater than 5.0 vol% and less than 6.7. The upper limit value T2b is greater than 6.7 vol% and less than 10.0 vol%. Therefore, the width U2 of Comparative Example Group 2 is greater than 0 and less than 5.0.

[0244] In FIG. 17, in the column of "Width U2 > 10?", "YES" or "NO" is shown. "YES" means that the width U2 is 10 or more. "NO" means that the width U2 is less than 10. The width U2 of Example Groups 1 and 2 is "YES", respectively. The width U2 of Comparative Example Groups 1 and 2 is "NO", respectively.

[0245] FIG. 17 shows the first mixing ratio R1 (vol%). The first mixing ratio R1 is a value obtained by adding 10 vol% to the optimal mixing ratio Ra. The first mixing ratio R1 of Example Group 1 is 20.0 vol%. The first mixing ratio R1 of Example Group 2 is 16.7 vol%. The first mixing ratio R1 of Comparative Example Group 1 is 16.7 vol%. The first mixing ratio R1 of Comparative Example Group 2 is 16.7 vol%.

[0246] FIG. 17 shows the first collapse rate D1 (%). The first collapse rate D1 is the collapse rate D when the mixing ratio R is the first mixing ratio R1. The first collapse rate D1 of Example Group 1 is 6.76 vol%. The first collapse rate D1 of Example Group 2 is 1.38 vol%. The first collapse rate D1 of Comparative Example Group 1 is 26.00 vol%. The first collapse rate D1 of Comparative Example Group 2 is 46.00 vol%.

[0247] Figure 17 shows the second reference value F2 (%). The second reference value F2 is a value obtained by adding 10% to the minimum collapse rate Da. The second reference value F2 of Example Group 1 is 10.19 vol%. The second reference value F2 of Example Group 2 is 10.66 vol%. The second reference value F2 of Comparative Example Group 1 is 10.05 vol%. The second reference value F2 of Comparative Example Group 2 is 25.12 vol%.

[0248] In Figure 17, "YES" or "NO" is shown in the column of "D1 < F2?". "YES" means that the first collapse rate D1 is lower than the second reference value F2. "NO" means that the first collapse rate D1 is equal to or higher than the second reference value F2. For Example Group 1, the first collapse rate D1 and the second reference value F2 are "YES". For Example Group 2, the first collapse rate D1 and the second reference value F2 are "YES". For Comparative Example Group 1, the first collapse rate D1 and the second reference value F2 are "NO". For Comparative Example Group 2, the first collapse rate D1 and the second reference value F2 are "NO".

[0249] In summary, in Example Groups 1 and 2, the first range T1 had a width U1 of 10 or more. In Example Groups 1 and 2, the second range T2 had a width U2 of 10 or more. In Example Groups 1 and 2, the first collapse rate D1 was lower than the second reference value F2. In contrast, in Comparative Example Groups 1 and 2, the first range T1 did not have a width U1 of 10 or more. In Comparative Example Groups 1 and 2, the second range T2 did not have a width U2 of 10 or more. In Comparative Example Groups 1 and 2, the first collapse rate D1 was equal to or higher than the second reference value F2. Thus, in Example Groups 1 and 2, the range of the mixing ratio R that can appropriately process the substrate W is wider than that in Comparative Example Groups 1 and 2. The range of the mixing ratio R that can appropriately process the substrate W corresponds to the process window regarding the mixing ratio R. Therefore, in Example Groups 1 and 2, the process window regarding the mixing ratio R is wider than that in Comparative Example Groups 1 and 2. In terms of the width of the process window, Example Groups 1 and 2 are superior to Comparative Example Groups 1 and 2.

[0250] Furthermore, in Example Group 1, the first range T1 includes a mixing ratio R of 16.7 vol% or more. When the mixing ratio R is 16.7 vol%, the height ratio P is approximately 250%. Therefore, in Example Group 1, even when the maximum height HM of the solidified film K is approximately 2.5 times the height HP of the pattern WP, the collapse rate D is equal to or less than the first reference value F1. Thus, in Example Group 1, even when the maximum height HM of the solidified film K is approximately 2.5 times the height HP of the pattern WP, the substrate W is appropriately processed.

[0251] In Example Group 1, the second range T2 includes a mixing ratio R of 25.0 vol% or more. When the mixing ratio R is 25.0 vol%, the height ratio P is approximately 350%. Therefore, in Example Group 1, even when the maximum height HM of the solidified film K is approximately 3.5 times the height HP of the pattern WP, the collapse rate D is 20% or less. Thus, in Example Group 1, even when the maximum height HM of the solidified film K is approximately 3.5 times the height HP of the pattern WP, the substrate W is appropriately processed.

[0252] In Example Group 2, the first range T1 includes a mixing ratio R of 25.0 vol% or more. When the mixing ratio R is 25.0 vol%, the height ratio P is approximately 400%. Therefore, in Example Group 2, even when the maximum height HM of the solidified film K is approximately 4.0 times the height HP of the pattern WP, the collapse rate D is equal to or less than the first reference value F1. Thus, in Example Group 2, even when the maximum height HM of the solidified film K is approximately 4.0 times the height HP of the pattern WP, the substrate W is appropriately processed.

[0253] In Example Group 2, the second range T2 includes a mixing ratio R of 25.0 vol% or more. When the mixing ratio R is 25.0 vol%, the height ratio P is approximately 400%. Therefore, in Example Group 2, even when the maximum height HM of the solidified film K is approximately 4.0 times the height HP of the pattern WP, the collapse rate D is 20% or less. Thus, in Example Group 2, even when the maximum height HM of the solidified film K is approximately 4.0 times the height HP of the pattern WP, the substrate W is appropriately processed.

[0254] <8. Mechanism of Collapse of Pattern WP (1)> The inventors of the present invention examined technical matters that contribute to the expansion of the process window regarding the mixing ratio R. As a result, the inventors inferred that the vapor pressure of the sublimable substance is important for expanding the process window. In Example Groups 1 and 2, the vapor pressure of the sublimable substance at room temperature is 1.0 Pa or less. In Comparative Example Groups 1 and 2, the vapor pressure of the sublimable substance at room temperature is greater than 1.0 Pa. The inventors inferred that this difference had a significant impact on the width of the process window. Specifically, the inventors assumed the mechanism of the collapse of the pattern WP as follows.

[0255] FIGS. 18(a), 18(b), and 18(c) are diagrams schematically showing the substrate W in the solidified film forming process of Comparative Example Groups 1 and 2, respectively.

[0256] Referring to FIG. 18(a). In the solidified film forming process, the liquid film G begins to change into the solidified film K. The liquid film G gradually decreases. The liquid film G still remains on the substrate W. The solidified film K gradually grows.

[0257] Referring to FIG. 18(b). As described above, in Comparative Example Groups 1 and 2, the sublimable substance has a vapor pressure greater than 1.0 Pa at room temperature. Therefore, after the liquid film G begins to change into the solidified film K, the solidified film K begins to sublime at an earlier timing. After the liquid film G begins to change into the solidified film K, the solidified film K sublimes at a faster rate. As a result, before the liquid film G disappears from the substrate W, the thickness HK of the solidified film K, for example, becomes significantly thinner. The thickness HK of the solidified film K, for example, becomes thinner than the thickness HG of the liquid film G. Before the liquid film G disappears from the substrate W, the upper surface K1 of the solidified film K, for example, becomes lower than the tip W1d of the convex portion W1.

[0258] In these cases, it is difficult for the solidified film K to appropriately support the convex portion W1. The pattern WP is more likely to be affected by the liquid film G remaining on the substrate W. Therefore, the pattern WP is more likely to collapse. It is more difficult to protect the pattern WP.

[0259] Refer to FIG. 18(c). In the worst case, before the liquid film G disappears from the substrate W, the solidified film K disappears from the substrate W. In this case, the upper surface G1 of the remaining liquid film G is in contact with the gas J. That is, the upper surface G1 becomes the gas-liquid interface again. The upper surface G1 intersects the pattern WP. That is, the gas-liquid interface intersects the pattern WP. For this reason, the pattern WP receives the surface tension of the liquid film G. Therefore, the pattern WP is extremely likely to collapse. It is extremely difficult to protect the pattern WP.

[0260] On the other hand, in Example Groups 1 and 2, the sublimable substance is 1.0 Pa or less at room temperature. For this reason, the timing at which the solidified film K starts to sublime is later. The sublimation rate of the solidified film K is slower. Therefore, until the liquid film G disappears from the substrate W, the thickness HK of the solidified film K is sufficiently large. Therefore, until the liquid film G disappears from the substrate W, the solidified film K appropriately supports the convex portion W1. In other words, while the liquid film G remains on the substrate W, the solidified film K appropriately supports the convex portion W1. Therefore, the pattern WP is hardly affected by the liquid film G. Without the liquid film G exerting a significant force on the substrate W, the liquid film G leaves the substrate W. For this reason, the pattern WP is difficult to collapse. The pattern WP is appropriately protected.

[0261] Note that in Example Groups 1 and 2, the sublimable substance has a vapor pressure of 0.1 Pa or more at room temperature. For this reason, in the sublimation process, the solidified film K sublimes appropriately. Therefore, the process in the sublimation step does not require an excessively long time.

[0262] On the contrary, when the vapor pressure of the sublimable substance at room temperature is less than 0.1 Pa, the process in the sublimation step requires an excessively long time. For this reason, when the vapor pressure of the sublimable substance at room temperature is less than 0.1 Pa, the substrate processing method is not practical.

[0263] <9. Mechanism of collapse of pattern WP (2)> The inventors observed how the liquid film G changed into the solidified film K in Example Groups 1 and 2 and Comparative Example Groups 1 and 2. Specifically, the inventors took videos of how the liquid film G changed into the solidified film K in Example Groups 1 and 2 and Comparative Example Groups 1 and 2 using an optical microscope. Then, the inventors made a comparative observation of each video of Example Groups 1 and 2 and Comparative Example Groups 1 and 2. As a result, the following observation results were obtained. Observation result: The solidified film K grew more rapidly in Comparative Example Groups 1 and 2 than in Example Groups 1 and 2. In other words, the solidified film K grew more slowly in Example Groups 1 and 2 than in Comparative Example Groups 1 and 2.

[0264] Incidentally, the solubility Rm of Example Groups 1 and 2 is smaller than that of Comparative Example Groups 1 and 2. In Example Groups 1 and 2, the solubility Rm is 150 vol% or more at room temperature. In Comparative Example Groups 1 and 2, the solubility Rm is less than 150 vol% at room temperature.

[0265] Based on the above-described observation results and the solubility Rm, the inventors inferred the following. When the solubility Rm is large, the growth rate of the solidified film K is fast. When the growth rate of the solidified film K is fast, the pattern WP is likely to collapse. On the other hand, when the solubility Rm is small, the growth rate of the solidified film K is slow. When the growth rate of the solidified film K is slow, the pattern WP is difficult to collapse. Therefore, the solubility Rm is also one of the factors that affect the process window.

[0266] Specifically, the mechanism of the collapse of the pattern WP assumed by the inventors is as follows.

[0267] Figs. 19(a) and 19(b) are diagrams schematically showing the substrate W in the solidified film formation process of Comparative Example Groups 1 and 2, respectively.

[0268] Referring to Fig. 19(a). After the treatment liquid g is supplied to the substrate W, the liquid film G begins to change into the solidified film K at an earlier timing. For example, before the upper surface G1 of the liquid film G becomes flat, the liquid film G begins to change into the solidified film K. For this reason, the solidified film K does not extend horizontally. The solidified film K is inclined.

[0269] In order to distinguish the two convex portions W1 shown in Fig. 19(a), each convex portion W1 is referred to as a first convex portion W1A and a second convex portion W1B. The thickness of the solidified film K near the first convex portion W1A is larger than the thickness of the solidified film K near the second convex portion W1B. The growth of the solidified film K near the first convex portion W1A is faster than the growth of the solidified film K near the second convex portion W1B. Thus, the growth of the solidified film K is significantly non-uniform over the substrate W.

[0270] Refer to Fig. 19(b). Also in Fig. 19(b), the solidified film K does not extend horizontally. Also in Fig. 19(b), the growth of the solidified film K is significantly non-uniform over the substrate W.

[0271] The solidified film K contacts the first convex portion W1A. Specifically, both the liquid film G and the solidified film K contact the first convex portion W1A. The upper surface G1 of the liquid film G intersects the first convex portion W1A. The upper surface G1 is the interface between the liquid film G and the solidified film K. For this reason, the first convex portion W1A receives capillary forces M1 and M2. The capillary force M1 acts on the intersection point L1 between the upper surface G1 and the first convex portion W1A. The capillary force M2 acts on the intersection point L2 between the upper surface G1 and the first convex portion W1A. The intersection point L1 is not located at the same height as the intersection point L2. The intersection point L1 is, for example, lower than the intersection point L2. For this reason, the capillary force M1 and the capillary force M2 do not balance each other. The capillary force M1 and the capillary force M2 are not canceled out by each other. Therefore, the first convex portion W1A is liable to collapse due to the capillary forces M1 and M2.

[0272] Figs. 20(a) and 20(b) are diagrams schematically showing the substrate W in the solidified film forming steps of Example Group 1 and Example Group 2, respectively.

[0273] Refer to Fig. 20(a). After the treatment liquid g is supplied to the substrate W, the liquid film G begins to change into the solidified film K at a later timing. For example, after the upper surface G1 of the liquid film G becomes flat, the liquid film G begins to change into the solidified film K. For this reason, the solidified film K extends horizontally. The solidified film K is not inclined.

[0274] To distinguish the two convex portions W1 shown in FIG. 20(a), each convex portion W1 is referred to as a third convex portion W1C and a fourth convex portion W1D. The thickness of the solidified film K near the third convex portion W1C is substantially equal to the thickness of the solidified film K near the fourth convex portion W1D. The growth of the solidified film K near the third convex portion W1C is substantially equal to the growth of the solidified film K near the fourth convex portion W1D. Thus, the growth of the solidified film K is substantially uniform over the substrate W.

[0275] Refer to FIG. 20(b). Also in FIG. 20(b), the solidified film K extends horizontally. Also in FIG. 20(b), the growth of the solidified film K is substantially uniform over the substrate W.

[0276] The solidified film K contacts the third convex portion W1C. Specifically, both the liquid film G and the solidified film K contact the third convex portion W1C. The upper surface G1 of the liquid film G intersects the third convex portion W1C. The upper surface G1 is the interface between the liquid film G and the solidified film K. For this reason, the third convex portion W1C receives capillary forces M3 and M4. The capillary force M3 acts on the intersection point L3 of the upper surface G1 and the first convex portion W1C. The capillary force M4 acts on the intersection point L4 of the upper surface G1 and the first convex portion W1C. The intersection point L3 is located at the same height as the intersection point L4. For this reason, the capillary force M3 and the capillary force M4 balance each other. The capillary force M3 and the capillary force M4 cancel each other out. Therefore, the third convex portion W1C is difficult to collapse due to the capillary forces M3 and M4.

[0277] <10. Effects of the Embodiment> The substrate processing method of the embodiment is for processing a substrate W on which a pattern WP is formed. The substrate processing method includes a processing liquid supply step, a solidified film formation step, and a sublimation step. In the processing liquid supply step, the processing liquid g is supplied to the substrate W. The processing liquid g contains a sublimable substance and a solvent. In the solidified film formation step, the solvent evaporates from the processing liquid g on the substrate W. In the solidified film formation step, a solidified film K is formed on the substrate W. The solidified film K contains a sublimable substance. In the sublimation step, the solidified film K sublimates. Due to the sublimation of the solidified film, the substrate is dried.

[0278] Here, the vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions for the treatment liquid g for appropriately treating the substrate W are looser. In other words, the process window regarding the treatment liquid g is wider.

[0279] Therefore, it is easy to generate the treatment liquid g that satisfies the conditions of the treatment liquid g. It is easy to store the treatment liquid g in a state where the treatment liquid g satisfies the conditions of the treatment liquid g. It is easy to supply the treatment liquid g that satisfies the conditions of the treatment liquid g to the substrate W.

[0280] Therefore, it is easier to appropriately dry the substrate W.

[0281] As described above, according to this substrate treatment method, the substrate W is appropriately dried.

[0282] The solubility Rm of the sublimable substance in the solvent is 150 vol% or more at room temperature. Therefore, the conditions for the treatment liquid g for appropriately treating the substrate W are even looser. Therefore, it is even easier to appropriately dry the substrate W.

[0283] The sublimable substance is, for example, 4-tert-butylphenol. The vapor pressure of 4-tert-butylphenol at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions for the treatment liquid g for appropriately treating the substrate W are looser. Therefore, it is easier to appropriately dry the substrate W.

[0284] The sublimable substance is, for example, acetophenone oxime. The vapor pressure of acetophenone oxime at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions for the treatment liquid g for appropriately treating the substrate W are looser. Therefore, it is easier to appropriately dry the substrate W.

[0285] The solvent is, for example, isopropyl alcohol. The solubility Rm of 4-tert-butylphenol in isopropyl alcohol is 150 vol% or more at room temperature. The solubility Rm of acetophenone oxime in isopropyl alcohol is 150 vol% or more at room temperature. Therefore, the conditions for the treatment liquid g for appropriately treating the substrate W are even looser. Thus, it is even easier to appropriately dry the substrate W.

[0286] When the mixing ratio R is within the first range T1, the collapse rate D is equal to or less than the first reference value F1. Here, the mixing ratio R is the ratio of the volume Q1g of the sublimable substance for generating the treatment liquid g to the volume Q2g of the solvent for generating the treatment liquid g. The collapse rate D is the probability that the pattern WP on the substrate W collapses when the substrate W is processed in the treatment liquid supply step, the solidified film formation step, and the sublimation step. The first reference value F1 is a value obtained by adding 5% to the minimum collapse rate Da. The minimum collapse rate Da is the smallest collapse rate D among a plurality of collapse rates D(%) obtained by changing the mixing ratio R. Therefore, when the mixing ratio R is within the first range T1, the collapse rate D is low. When the mixing ratio R is within the first range T1, the pattern WP on the substrate W is preferably protected. When the mixing ratio R is within the first range T1, the substrate W is appropriately dried.

[0287] The first range T1 has a width U1 of 10 or more. That is, the width U1 of the first range T1 is wide. Here, the mixing ratio R is one of the conditions of the treatment liquid g. The first range T1 corresponds to the range of the conditions of the treatment liquid g. The first range T1 corresponds to the process window for the treatment liquid g. Therefore, the conditions for the treatment liquid g are loose. The process window for the treatment liquid g is wide. Thus, it is even easier to appropriately dry the substrate W.

[0288] In Example Group 1, for example, when the maximum height HM of the solidified film K is 2.5 times the height HP of the pattern WP, the collapse rate D is equal to or less than the first reference value F1. In this way, the process window for the treatment liquid g is even wider. Thus, it is even easier to appropriately dry the substrate W.

[0289] In Example Group 2, for example, when the maximum height HM of the solidified film K is 4.0 times the height HP of the pattern WP, the collapse rate D is equal to or less than the first reference value F1. Thus, the process window for the treatment liquid g is even wider. Therefore, it is even easier to appropriately dry the substrate W.

[0290] When the mixing ratio R is the optimal mixing ratio Ra, the collapse rate D is the minimum collapse rate Da. When the mixing ratio R is the first mixing ratio R1, the collapse rate D is the first collapse rate D1. Here, the first mixing ratio R1 is a value obtained by adding 10 vol% to the optimal mixing ratio Ra.

[0291] The first collapse rate D1 is lower than the second reference value F2. Here, the second reference value F2 is a value obtained by adding 10% to the minimum collapse rate Da. Therefore, when the mixing ratio R increases by 10 vol% from the optimal mixing ratio Ra, the collapse rate D increases by less than 10% from the minimum collapse rate Da. In other words, when the increase amount of the mixing ratio R from the optimal mixing ratio Ra is 10, the increase amount of the collapse rate D from the minimum collapse rate Da is less than 10. Thus, when the mixing ratio R increases by 10 (vol%) from the optimal mixing ratio Ra, the collapse rate D does not increase significantly. When the mixing ratio R increases by 10 (vol%) from the optimal mixing ratio Ra, the increase amount of the collapse rate D is small. Therefore, when the mixing ratio R is equal to or greater than the optimal mixing ratio Ra and equal to or less than the first mixing ratio R1, the substrate W is appropriately dried.

[0292] Here, the mixing ratio R is one of the conditions of the treatment liquid g. The range of the mixing ratio R from the optimal mixing ratio Ra to the first mixing ratio R1 corresponds to the range of the conditions of the treatment liquid g. The range of the mixing ratio R from the optimal mixing ratio Ra to the first mixing ratio R1 corresponds to the process window for the treatment liquid g. Therefore, the conditions of the treatment liquid g are loose. The process window for the treatment liquid g is wide. Therefore, it is easier to appropriately dry the substrate W.

[0293] The minimum collapse rate Da is 5% or less. When the minimum collapse rate Da is 5% or less, the first reference value F1 is 10% or less. Therefore, when the mixing ratio R is within the first range T1, the collapse rate D is 10% or less. When the mixing ratio R is within the first range T1, the collapse rate D is low. When the mixing ratio R is within the first range T1, the pattern WP on the substrate W is preferably protected. Therefore, it is easier to appropriately dry the substrate W.

[0294] Furthermore, when the minimum collapse rate Da is 5% or less, the second reference value F2 is 15% or less. When the minimum collapse rate Da is 5% or less, the first collapse rate D1 is less than 15%. Therefore, when the mixing ratio R is the optimum mixing ratio Ra, the collapse rate D is 5% or less. When the mixing ratio R is the first mixing ratio R1, the collapse rate D is less than 15%. Thus, when the mixing ratio R is within the range from the optimum mixing ratio Ra to the first mixing ratio R1, the collapse rate D is low. When the mixing ratio R is within the range from the optimum mixing ratio Ra to the first mixing ratio R1, the pattern WP on the substrate W is preferably protected. Therefore, it is easier to appropriately dry the substrate W.

[0295] The minimum collapse rate Da is 1% or less. When the minimum collapse rate Da is 1% or less, the first reference value F1 is 6% or less. Therefore, when the mixing ratio R is within the first range T1, the collapse rate D is 6% or less. When the mixing ratio R is within the first range T1, the collapse rate D is even lower. When the mixing ratio R is within the first range T1, the pattern WP on the substrate W is even more preferably protected. Therefore, it is even easier to appropriately dry the substrate W.

[0296] Furthermore, when the minimum collapse rate Da is 1% or less, the second reference value F2 is 11% or less. When the minimum collapse rate Da is 1% or less, the first collapse rate D1 is less than 11%. Therefore, when the mixing ratio R is the optimum mixing ratio Ra, the collapse rate D is 1% or less. When the mixing ratio R is the first mixing ratio R1, the collapse rate D is less than 11%. Thus, when the mixing ratio is within the range from the optimum mixing ratio to the first mixing ratio, the collapse rate D is even lower. When the mixing ratio is within the range from the optimum mixing ratio to the first mixing ratio, the pattern WP on the substrate W is more suitably protected. Therefore, it is even easier to appropriately dry the substrate W.

[0297] When the mixing ratio R is within the second range T2, the collapse rate D is 20 (%) or less. Therefore, when the mixing ratio R is within the second range T2, the collapse rate D is low. When the mixing ratio R is within the second range T2, the pattern WP on the substrate W is suitably protected. When the mixing ratio R is within the second range T2, the substrate W is appropriately processed.

[0298] The second range T2 has a width U2 of 10 or more. That is, the width U2 of the second range T2 is wide. Here, the mixing ratio R is one of the conditions of the treatment liquid g. The second range T2 corresponds to the range of the conditions of the treatment liquid g. The second range T2 corresponds to the process window for the treatment liquid g. Therefore, the conditions of the treatment liquid g are loose. The process window for the treatment liquid g is wide. Thus, it is even easier to appropriately dry the substrate W.

[0299] In Example Group 1, when the maximum height HM of the solidified film K is 3.5 times the height HP of the pattern WP, the collapse rate D is 20% or less. In this way, the process window for the treatment liquid is even wider. Thus, it is even easier to appropriately dry the substrate.

[0300] In Example Group 2, when the maximum height HM of the solidified film K is 4.0 times the height HP of the pattern WP, the collapse rate D is 20% or less. In this way, the process window for the treatment liquid is even wider. Thus, it is even easier to appropriately dry the substrate.

[0301] The substrate processing apparatus 1 includes a substrate holding unit 13 and a liquid supply unit 15a. The substrate holding unit 13 holds the substrate W. The liquid supply unit 15a supplies the processing liquid g to the substrate W held by the substrate holding unit 13. The processing liquid g contains a sublimable substance and a solvent. Therefore, when the processing liquid g is supplied to the substrate W, the solvent evaporates from the processing liquid g on the substrate W. Due to the evaporation of the solvent, the solidified film K is formed on the substrate W. The solidified film K contains a sublimable substance. Thus, the solidified film K sublimates. Due to the sublimation of the solidified film K, the substrate W is dried.

[0302] Here, the vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions for the processing liquid g for appropriately processing the substrate W are looser. In other words, the process window for the processing liquid g is wider. Thus, it is easier to appropriately dry the substrate W.

[0303] As described above, according to the present substrate processing apparatus 1, the substrate W is appropriately dried.

[0304] The solubility Rm of the sublimable substance in the solvent is 150 vol% or more at room temperature. Therefore, the conditions for the processing liquid g for appropriately processing the substrate W are even looser. Thus, it is even easier to appropriately dry the substrate W.

[0305] The processing liquid g is used for drying the substrate W on which the pattern WP is formed. Specifically, the processing liquid g is a drying aid liquid. The processing liquid g contains a sublimable substance and a solvent. The vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less. Therefore, the conditions for the processing liquid g for appropriately processing the substrate W are looser. In other words, the process window for the processing liquid g is wider. Thus, by using the processing liquid g, it is easier to appropriately dry the substrate W. Specifically, by using the processing liquid g, while the pattern WP on the substrate W is preferably protected, it is easier to dry the substrate W. Thus, the processing liquid g is useful for drying the substrate W.

[0306] As described above, the substrate W is appropriately dried using the treatment liquid g.

[0307] The solubility Rm of the sublimable substance in the solvent g is 150 vol% or more at normal temperature. For this reason, the conditions for the treatment liquid g for appropriately treating the substrate W are looser. Therefore, it is easier to appropriately dry the substrate W using the treatment liquid g. Thus, the substrate W is more appropriately dried using the treatment liquid g.

[0308] The sublimable substance is, for example, 4-tert-butylphenol. The vapor pressure of 4-tert-butylphenol at normal temperature is 0.1 Pa or more and 1.0 Pa or less. For this reason, the conditions for the treatment liquid g for appropriately treating the substrate W are looser. Therefore, it is easier to appropriately dry the substrate W using the treatment liquid g.

[0309] The sublimable substance is, for example, acetophenone oxime. The vapor pressure of acetophenone oxime at normal temperature is 0.1 Pa or more and 1.0 Pa or less. For this reason, the conditions for the treatment liquid g for appropriately treating the substrate W are looser. Therefore, it is easier to appropriately dry the substrate W using the treatment liquid g.

[0310] The solvent is, for example, isopropyl alcohol. The solubility Rm of 4-tert-butylphenol in isopropyl alcohol is 150 vol% or more at normal temperature. The solubility Rm of acetophenone oxime in isopropyl alcohol is 150 vol% or more at normal temperature. For this reason, the conditions for the treatment liquid g for appropriately treating the substrate W are looser. Therefore, it is easier to appropriately dry the substrate W using the treatment liquid g.

[0311] <11. Modified Embodiment> The present invention is not limited to the embodiments and can be modified as follows.

[0312] (1) In the embodiment, the sublimable substance was, for example, 4-tert butylphenol. In the embodiment, the sublimable substance was, for example, acetophenone oxime. However, it is not limited thereto. The sublimable substance may be appropriately changed to other compounds. Also in this modified embodiment, the sublimable substance preferably has a vapor pressure of 0.1 Pa or more and 1.0 Pa or less at normal temperature.

[0313] (2) In the embodiment, the solvent was, for example, IPA. However, it is not limited thereto. The solvent may be appropriately changed to other compounds. Also in this modified embodiment, the ability of the solvent to dissolve the sublimable substance is preferably high.

[0314] (3) In the embodiment, the collapse rate D was the median value dm among a plurality of local collapse rates di. However, it is not limited thereto. For example, the collapse rate D may be, for example, the average value da of a plurality of local collapse rates di. Alternatively, the collapse rate D may be the ratio of the sum of the numbers NTi in each local area Ei to the sum of the numbers NPi in each local area Ei.

[0315] (4) In the embodiment, the treatment liquid condition information includes a target regarding the mixing ratio R. However, it is not limited thereto. For example, the treatment liquid condition information may include, for example, a target regarding the initial concentration V0. The target regarding the initial concentration V0 may be defined by one value. The target regarding the initial concentration V0 may be defined by a range between two different values.

[0316] (5) In the embodiment, before the treatment liquid g was supplied to the first supply unit 15a, the treatment liquid g was generated. In the embodiment, the first supply source 19a generated the treatment liquid in the tank 22. However, it is not limited thereto. For example, when the treatment liquid g was supplied to the first supply unit 15a, the treatment liquid g may be generated. For example, the first supply source 19a may generate the treatment liquid g in the flow path for supplying the treatment liquid g to the first supply unit 15a.

[0317] FIG. 21 is a diagram showing the configuration of the processing unit 11 and the first supply source 19a of the modified embodiment. Note that the same components as those in the embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

[0318] The first supply source 19a includes a first tank 41 and a second tank 42. The first tank 41 stores the sublimable substance. For example, the first tank 41 may store a solvent together with the sublimable substance. The second tank 42 stores the solvent. For example, the second tank 42 stores only the solvent.

[0319] The first supply source 19a includes a mixing unit 44. The mixing unit 44 is communicatively connected to the first tank 41 and the second tank 42. The mixing unit 44 generates the processing liquid g.

[0320] The mixing unit 44 is communicatively connected to the first supply unit 15a. The mixing unit 44 supplies the processing liquid g to the first supply unit 15a.

[0321] Specifically, the mixing unit 44 includes pipes 45a, 45b and a joint 46. The pipe 45a is communicatively connected to the first tank 41. The pipe 45b is communicatively connected to the second tank 42. The joint 46 is communicatively connected to the pipes 45a, 45b. The joint 46 is further communicatively connected to the pipe 17a. The pipes 45a, 45b are communicatively connected to the pipe 17a via the joint 46.

[0322] The mixing unit 44 includes pumps 47a, 47b. The pumps 47a, 47b are respectively provided in the pipes 45a, 45b. The pump 47a sends the sublimable substance from the first tank 41 to the joint 46 through the pipe 45a. The pump 47b sends the solvent from the second tank 42 to the joint 46 through the pipe 45b.

[0323] The mixing unit 44 includes filters 48a, 48b. The filters 48a, 48b are respectively provided in the pipes 45a, 45b. The sublimable substance passes through the filter 48a. The filter 48a filters the sublimable substance. The solvent passes through the filter 48b. The filter 48b filters the solvent.

[0324] The mixing section 44 includes valves 49a and 49b. Valves 49a and 49b are respectively provided in pipes 45a and 45b. Valve 49a adjusts the flow rate of the sublimable substance flowing through pipe 45a. Valve 49b adjusts the flow rate of the solvent flowing through pipe 45b. Valves 49a and 49b may each include, for example, a flow control valve. Valves 49a and 49b may each include, for example, a flow control valve and an on-off valve.

[0325] An operation example of the first supply source 19a in the modified embodiment will be described. In the processing liquid supply step, the first supply source 19a generates the processing liquid g and sends the processing liquid g to the first supply section 15a. Specifically, valves 49a and 49b open. Pump 47a pumps the sublimable substance from the first tank 41 to the joint 46. Pump 47b pumps the solvent from the second tank 42 to the joint 46. The sublimable substance and the solvent are mixed at the joint 46. The sublimable substance and the solvent become the processing liquid g at the joint 46. Further, the processing liquid g flows from the joint 46 to the first supply section 15a. The nozzle 16a discharges the processing liquid g.

[0326] According to this modified embodiment, it is not necessary to store the processing liquid g before the processing liquid g is supplied to the first supply section 15a. Therefore, the mixing ratio R of the processing liquid is accurately controlled. Thus, the substrate W is dried more appropriately.

[0327] Furthermore, the first supply source 19a does not include the tank 22. Therefore, the structure of the first supply source 19a is suitably simplified. The first supply source 19a is suitably miniaturized.

[0328] (6) The substrate processing method of the embodiment includes a chemical solution supply step, a rinse solution supply step, and a replacement solution supply step. However, it is not limited thereto. For example, at least any one of the chemical solution supply step, the rinse solution supply step, and the replacement solution supply step may be omitted. For example, all of the chemical solution supply step, the rinse solution supply step, and the replacement solution supply step may be omitted.

[0329] (7) In the embodiment, when the processing liquid supply step is executed, a liquid (for example, a replacement liquid) was present on the substrate W. That is, in the processing liquid supply step, the processing liquid g was supplied to the substrate W in a non-dried state. However, it is not limited to this. For example, when the processing liquid supply step is executed, the liquid (for example, a replacement liquid) may not be present on the substrate W. For example, in the processing liquid supply step, the processing liquid g may be supplied to the dried substrate W.

[0330] (8) In the processing liquid supply step of the embodiment, the processing liquid g removed the replacement liquid from the substrate W. However, it is not limited to this. For example, in the processing liquid supply step, the processing liquid g may clean the substrate W. For example, in the processing liquid supply step, the processing liquid g may remove foreign substances adhering to the substrate W. For example, in the processing liquid supply step, the processing liquid g may dissolve foreign substances adhering to the substrate W. The foreign substances are, for example, resist residues.

[0331] (9) In the solidified film forming step of the embodiment, the drying gas was not supplied to the substrate W. However, it is not limited to this. In the solidified film forming step, the drying gas may be supplied to the substrate W. In the solidified film forming step, the drying gas may be supplied to the processing liquid g on the substrate W. According to this modified embodiment, in the solidified film forming step, the processing liquid g on the substrate W is exposed to the drying gas. Therefore, in the solidified film forming step, the solvent efficiently evaporates from the processing liquid g on the substrate W. In the solidified film forming step, the solidified film K is efficiently formed on the substrate W.

[0332] (10) In the embodiment, the pattern WP on the substrate W may be formed on the substrate W, for example, before the processing unit 11 processes the substrate W. Alternatively, the pattern WP may be formed on the substrate W, for example, in the chemical liquid supply step (step S12).

[0333] (11) Regarding the embodiment and each of the modified embodiments described in (1) to (10) above, each configuration may be appropriately changed by substituting or combining each configuration with the configurations of other modified embodiments.

Explanation of Reference Numerals

[0334] 1 … Substrate processing apparatus 10 … Control unit 11 … Processing unit 13 … Substrate holding unit 15 … Supply unit 15a … First supply unit (processing liquid supply unit) 19a … First supply source A … Concave portion D … Collapse rate (%) D1 … First collapse rate (%) Da … Minimum collapse rate (%) F1 … First reference value (%) F2 … Second reference value (%) g … Processing liquid G … Liquid film of processing liquid G1 … Upper surface of liquid film HG … Thickness of liquid film HK … Thickness of solidified film HM … Maximum height of solidified film (initial height of solidified film) HP … Height of convex portion (height of pattern) K … Solidified film K1 … Upper surface of solidified film Q1g … Volume of sublimable substance for generating processing liquid Q2g … Volume of solvent for generating processing liquid R … Mixing ratio (vol%) Rm … Solubility of sublimable substance in solvent (vol%) T1 … First range T2 … Second range U1 … Width of first range [[ID=�9]]U2 … Width of second range W … Substrate WP … Pattern W1, W1 … Convex portion W1p … Base end of convex portion W1d … Tip of convex portion

Claims

1. A substrate processing method for processing a substrate on which a pattern is formed, comprising: a treatment liquid supply step of supplying a treatment liquid containing a sublimable substance and a solvent to the substrate; a solid film forming step of evaporating the solvent from the treatment liquid on the substrate to form a solid film containing the sublimable substance on the substrate; a sublimation step of sublimating the solid film; wherein the vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less; the solubility of the sublimable substance in the solvent is 150 vol% or more at room temperature. Substrate processing method.

2. A substrate processing method for processing a substrate on which a pattern is formed, comprising: a treatment liquid supply step of supplying a treatment liquid containing a sublimable substance and a solvent to the substrate; a solid film forming step of evaporating the solvent from the treatment liquid on the substrate to form a solid film containing the sublimable substance on the substrate; a sublimation step of sublimating the solid film; wherein the vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less; the sublimable substance is 4-tert-butylphenol. Substrate processing method.

3. A substrate processing method for processing a substrate on which a pattern is formed, comprising: a treatment liquid supply step of supplying a treatment liquid containing a sublimable substance and a solvent to the substrate; a solid film forming step of evaporating the solvent from the treatment liquid on the substrate to form a solid film containing the sublimable substance on the substrate; a sublimation step of sublimating the solid film; wherein the vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less; the sublimable substance is acetophenone oxime. Substrate processing method.

4. In the substrate processing method according to any one of Claims 1 to 3, the solvent is isopropyl alcohol. Substrate processing method.

5. In the substrate processing method according to any one of Claims 1 to 4, the ratio of the volume of the sublimable substance for generating the treatment liquid to the volume of the solvent for generating the treatment liquid is defined as the mixing ratio (vol%); the probability that the pattern on the substrate collapses when the substrate is processed in the treatment liquid supply step, the solid film forming step, and the sublimation step is defined as the collapse rate (%); the smallest collapse rate among the plurality of collapse rates (%) obtained by changing the mixing ratio is defined as the minimum collapse rate (%); a value obtained by adding 5% to the minimum collapse rate is defined as the first reference value (%); the range of the mixing ratio when the collapse rate is equal to or less than the first reference value is defined as the first range. The first range has a width of 10 or more. Substrate processing method.

6. A substrate processing method according to any one of claims 1 to 5, a ratio of the volume of the sublimable substance for generating the treatment liquid to the volume of the solvent for generating the treatment liquid is defined as a blending ratio (vol %); a probability that the pattern on the substrate will collapse when the substrate is processed in the processing liquid supplying step, the solidified film forming step, and the sublimation step is a collapse rate (%); Among the plurality of collapse rates (%) obtained by changing the blending ratio, the smallest collapse rate is defined as the minimum collapse rate (%), The blending ratio when the collapse rate is the minimum collapse rate is defined as an optimal blending ratio (vol%), The value obtained by adding 10 vol% to the optimum blending ratio is defined as a first blending ratio (vol%), The collapse rate when the blending ratio is the first blending ratio is defined as a first collapse rate (%), The value obtained by adding 10% to the minimum collapse rate is set as the second standard value (%), The first collapse rate is lower than the second reference value. Substrate processing method.

7. A substrate processing method according to any one of claims 1 to 6, a ratio of the volume of the sublimable substance for generating the treatment liquid to the volume of the solvent for generating the treatment liquid is defined as a blending ratio (vol %); a probability that the pattern on the substrate will collapse when the substrate is processed in the processing liquid supplying step, the solidified film forming step, and the sublimation step is a collapse rate (%); The range of the blending ratio when the collapse rate is 20(%) or less is defined as a second range, The second range has a width of 10 or more. Substrate processing method.

8. A substrate processing apparatus, a substrate holder that holds a substrate; a processing liquid supply unit that supplies a processing liquid containing a sublimable substance and a solvent to the substrate held by the substrate holding unit; Equipped with The vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less, The solubility of the sublimable substance in the solvent is 150 vol % or more at room temperature. Substrate processing equipment.

9. A substrate processing apparatus, a substrate holder that holds a substrate; a processing liquid supply unit that supplies a processing liquid containing a sublimable substance and a solvent to the substrate held by the substrate holding unit; Equipped with The vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less, The sublimable substance is 4-tert-butylphenol. Substrate processing equipment.

10. A substrate processing apparatus, a substrate holder that holds a substrate; A processing liquid supply unit that supplies a processing liquid containing a sublimable substance and a solvent to a substrate held by the substrate holding unit; comprising; The vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less; The sublimable substance is acetophenone oxime Substrate processing apparatus.

11. A processing liquid used for drying a substrate on which a pattern is formed, The processing liquid, a sublimable substance, a solvent, and comprising; The vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less; The solubility of the sublimable substance in the solvent is 150 vol% or more at room temperature Processing liquid.

12. A processing liquid used for drying a substrate on which a pattern is formed, The processing liquid, a sublimable substance, a solvent, and comprising; The vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less; The sublimable substance is 4-tert-butylphenol Processing liquid.

13. A processing liquid used for drying a substrate on which a pattern is formed, The processing liquid, a sublimable substance, a solvent, and comprising; The vapor pressure of the sublimable substance at room temperature is 0.1 Pa or more and 1.0 Pa or less; The sublimable substance is acetophenone oxime Processing liquid.

14. In the processing liquid according to any one of Claims 11 to 13, The solvent is isopropyl alcohol Processing liquid.

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