Substrate processing method

Abstract

The purpose of this disclosure is to provide a technique that can effectively reduce the collapse rate of patterns. The substrate processing method includes a holding step, a liquid supply step, a drying liquid supply step, and a drying step. In the holding step, a substrate having a first main surface with a pattern formed and a second main surface opposite to the first main surface is held. In the liquid supply step, a processing liquid is supplied to the first main surface of the substrate. In the drying liquid supply step, after the liquid supply step, a drying liquid is supplied to the first main surface of the substrate. In the drying step, within a predetermined period after the drying liquid supply step, the second main surface of the substrate is heated, and the substrate temperature of the first main surface of the substrate is set above the substrate temperature in the drying liquid supply step, thereby drying the substrate.

Description

Substrate processing method The present disclosure relates to a substrate processing method. Previously, a single-wafer substrate processing apparatus for processing a substrate has been disclosed (for example, Patent Document 1). In Patent Document 1, after supplying a cleaning liquid to the substrate, isopropyl alcohol having a lower surface tension than the cleaning liquid is supplied to the substrate, and then the substrate is dried. Thereby, pattern collapse of the substrate during drying is suppressed. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-23182 [Problems to be Solved by the Invention] However, in Patent Document 1, the temperature of the isopropyl alcohol is not considered. Therefore, the pattern collapse rate cannot be effectively reduced. Therefore, an object of the present disclosure is to provide a technique capable of effectively reducing the pattern collapse rate. [Technical Means for Solving the Problems] A first aspect is a substrate processing method, comprising: a holding step of holding a substrate having a first main surface formed with a pattern and a second main surface opposite to the first main surface; a liquid supply step of supplying a processing liquid to the first main surface of the substrate; a drying liquid supply step of supplying a drying liquid to the first main surface of the substrate after the liquid supply step; and a drying step of heating the second main surface of the substrate within a specified period after the drying liquid supply step, setting the substrate temperature of the first main surface of the substrate to be equal to or higher than the substrate temperature in the drying liquid supply step, and drying the substrate. A second aspect is the substrate processing method according to the first aspect, wherein within the specified period, the substrate temperature of at least a part of the first main surface of the substrate is set to be equal to or higher than the boiling point of the drying liquid. A third aspect is the substrate processing method according to the first or second aspect, wherein in the drying liquid supply step, the second main surface of the substrate is heated with a first heat amount per unit time; and in the specified period of the drying step, the second main surface of the substrate is heated with a second heat amount per unit time greater than the first heat amount. A fourth aspect is the substrate processing method according to any one of the first to third aspects, wherein a heat medium is supplied to the second main surface of the substrate within the specified period. The fifth aspect is the substrate processing method as in the third aspect, wherein in the drying liquid supply step, a heat medium is supplied to the second main surface of the substrate, and the heat medium is obtained by mixing a high-temperature heat medium and a low-temperature heat medium having a temperature lower than that of the high-temperature heat medium; the mixing ratio of the high-temperature heat medium and the low-temperature heat medium is adjusted, and the heat medium having a temperature higher than that of the heat medium in the drying liquid supply step is supplied to the second main surface of the substrate for at least the specified period in the drying step. The sixth aspect is the substrate processing method as in the fourth or fifth aspect, wherein in the specified period, the heat medium having a temperature above the boiling point of the drying liquid is supplied to the second main surface of the substrate. The seventh aspect is the substrate processing method as in any one of the fourth to sixth aspects, wherein in the drying liquid supply step, the heat medium having a temperature above the boiling point of the drying liquid is supplied to the second main surface of the substrate, and the drying liquid is supplied at a flow rate such that the substrate temperature of the first main surface of the substrate does not reach the boiling point. The eighth aspect is the substrate processing method as in any one of the fourth to seventh aspects, wherein the heat medium contains a liquid; in the drying liquid supply step, the drying liquid is supplied to the first main surface of the substrate in a state where a blocking plate having a facing surface facing the first main surface of the substrate is located at a blocking treatment position; in the specified period of the drying step, in a state where the blocking plate is moved to a drying position closer to the first main surface than the blocking treatment position, an inert gas is supplied from a gas ejection port at the center of the blocking plate to the first main surface of the substrate. The ninth aspect is the substrate processing method as in the eighth aspect, wherein in the specified period, the heated inert gas is supplied to the first main surface of the substrate. The tenth aspect is the substrate processing method as in the eighth or ninth aspect, wherein in the drying liquid supply step, the inert gas is supplied to the first main surface of the substrate through a gas flow path inside the blocking plate having a diameter-expanding flow path that widens toward the gas ejection port; the blocking plate is moved from the blocking treatment position to the drying position, and the flow rate of the inert gas is increased. The eleventh aspect is the substrate processing method as in the tenth aspect, wherein in the drying liquid supply step, the drying liquid is supplied to the first main surface of the substrate in a state where the blocking plate is located at a first blocking treatment position, which is one of the blocking treatment positions, and then the drying liquid is supplied, and the blocking plate is moved to one of the blocking treatment positions and a second blocking treatment position closer to the first main surface of the substrate than the first blocking treatment position. The 12th aspect is a substrate processing method according to any one of the 1st to 11th aspects, wherein within the specified period of the drying process, the substrate is rotated at a rotational speed higher than the rotational speed of the substrate in the drying liquid supply process. The 13th aspect is a substrate processing method according to any one of the 1st to 12th aspects, wherein in the drying liquid supply process, the second main surface of the substrate is heated only during the later time within the drying liquid supply time for supplying the drying liquid. [Effects of the Invention] According to the 1st aspect, the second main surface of the substrate is heated within a specified period. Therefore, the drying liquid can be evaporated in a state where the surface tension of the drying liquid is smaller and the evaporation speed is higher. Therefore, collapse of the pattern during drying of the first main surface of the substrate can be suppressed. According to the 2nd aspect, the surface tension of the drying liquid within the specified period can be further reduced, and the evaporation speed of the drying liquid can be further increased. Therefore, the collapse rate of the pattern can be further reduced. According to the 3rd aspect, in the drying liquid supply process, the second main surface of the substrate is heated with a relatively small first amount of heat, and the drying liquid is supplied to the first main surface of the substrate. Therefore, in a state where the drying liquid is supplied, an increase in the substrate temperature can be suppressed, and boiling of the drying liquid can be suppressed. Therefore, adhesion of fine particles can be suppressed. On the other hand, within the specified period of the drying process, in a state where the drying liquid is not supplied to the substrate, the second main surface of the substrate is heated with a relatively large second amount of heat. Therefore, the surface tension of the drying liquid within the specified time can be further reduced, and the evaporation speed can be further increased. Therefore, the collapse rate of the pattern can be further reduced. According to the 4th aspect, the second main surface of the substrate can be heated simply. According to the 5th aspect, since the mixing ratio is adjusted, the temperature of the heat medium supplied to the second main surface of the substrate can be rapidly increased. Therefore, in the drying process, the drying liquid can be heated at an earlier timing. Therefore, the collapse rate of the pattern can be further reduced. According to the 6th aspect, in the drying process, the surface tension of the drying liquid can be further reduced, and the evaporation speed can be further increased. Therefore, the collapse rate of the pattern can be further reduced. According to the 7th aspect, in the drying liquid supply process, the temperature of the first main surface of the substrate can be increased to a temperature closer to the boiling point of the drying liquid. According to the 8th aspect, within the specified period, the shielding plate is located close to the drying position of the substrate. Therefore, the interval between the substrate and the shielding plate can be narrowed, and the flow rate of the inert gas flowing out from between the substrate and the shielding plate to the radially outer side can be increased. Therefore, it is possible to suppress the heat medium from winding around from the second main surface to the first main surface via the periphery of the substrate. According to the 9th aspect, the drying liquid can be evaporated in a shorter time. Therefore, the collapse rate of the pattern can be further reduced. According to the tenth aspect, it is possible to suppress the drying liquid from adhering to the shutter, and further reduce the collapse rate of the pattern. According to the eleventh aspect, immediately before the drying process, the shutter is located at the second shut-off processing position. Therefore, the shutter can be moved to the drying position more quickly. As a result, the substrate can be dried more quickly, and the collapse rate of the pattern can be further reduced. According to the twelfth aspect, the drying liquid can be evaporated in a shorter time. Therefore, the collapse rate of the pattern can be further reduced. According to the thirteenth aspect, power consumption can be reduced. Hereinafter, embodiments will be described in detail with reference to the drawings. In the drawings, for the purpose of easy understanding, the dimensions or quantities of respective parts are exaggerated or simplified as needed. Also, parts having the same configuration and function are denoted by the same reference numerals, and repeated descriptions are omitted in the following description. Furthermore, in the following description, the same constituent elements are denoted by the same reference numerals and illustrated, and their names and functions are also made the same. Therefore, there are cases where the detailed descriptions thereof are omitted to avoid duplication. Furthermore, in the following description, even when ordinal numbers such as "first" or "second" are used, these terms are used for the convenience of understanding the content of the embodiments and are not limited to the order that may be generated by these ordinal numbers. When expressions indicating relative or absolute positional relationships (such as "in a direction", "along a direction", "parallel", "orthogonal", "center", "concentric", "coaxial", etc.) are used, unless otherwise stated, this expression not only strictly represents the positional relationship, but also represents a state where the angle or distance is relatively displaced within the tolerance or within a range where the same degree of function can be obtained. When expressions indicating an equal state (such as "the same", "equal", "homogeneous", etc.) are used, unless otherwise stated, this expression not only strictly represents the equal state quantitatively, but also represents a state where there is a tolerance or a difference in the same degree of function. When expressions indicating a shape (such as "quadrilateral shape" or "cylindrical shape", etc.) are used, unless otherwise stated, this expression not only strictly represents the shape geometrically, but also represents a shape having, for example, unevenness or chamfers within a range where the same degree of effect can be obtained. When an expression using "provided with", "having", "equipped with", "including", or "containing" a constituent element is used, this expression is not an exclusive expression excluding the existence of other constituent elements. When an expression using "at least one of A, B, and C" is used, this expression includes only A, only B, only C, any two of A, B, and C, and all of A, B, and C. <First Embodiment> <Overall Configuration of Substrate Processing Apparatus> FIG. 1 is a plan view schematically showing an example of the configuration of a substrate processing apparatus 100. The substrate processing apparatus 100 is a single-wafer processing apparatus that processes substrates W one by one. 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 plate shape having a first main surface Wa and a second main surface Wb. The second main surface Wb is the surface on the side opposite to the first main surface Wa. Hereinafter, the substrate W is assumed to be a semiconductor wafer. The substrate W has, for example, a disk shape. The diameter of the substrate W is, for example, about 300 mm, and the thickness of the substrate W is, for example, about 0.5 mm or more and about 3 mm or less. A pattern is formed on the main surface of the substrate W. The pattern described here includes at least one of, for example, a wiring pattern, an electrode pattern, a semiconductor pattern, and an insulating pattern. The aspect ratio in the pattern is, for example, 5 or more and 500 or less. The pattern width is, for example, 3 nm or more and 50 nm or less. Such a pattern with a high aspect ratio is likely to collapse. In the example of FIG. 1, the substrate processing apparatus 100 includes a transfer block 110, a processing block 120, and a control unit 90. The processing block 120 is a part that mainly processes the substrate W, and the transfer block 110 is a part that mainly transfers the substrate W between the outside of the substrate processing apparatus 100 and the processing block 120. The transfer block 110 includes a load port 111 and a first transfer unit 112. A substrate container (hereinafter referred to as a carrier) C carried in from the outside is placed on the load port 111. In the carrier C, a plurality of substrates W are accommodated in a state of being arranged at intervals in the vertical direction, for example. In the example of FIG. 1, a plurality of load ports 111 are arranged. The first transfer unit 112 is a transfer robot that can take out an unprocessed substrate W from the carrier C placed on each load port 111. The first transfer unit 112 may also be referred to as a transfer robot. The first transfer unit 112 transfers the unprocessed substrate W taken out from the carrier C to the processing block 120. The processing block 120 can process the unprocessed substrate W. Further, the first transfer unit 112 can receive the processed substrate W from the processing block 120 and transfer the processed substrate W to the carrier C on the load port 111. In the example of FIG. 1, the processing block 120 includes a plurality of processing units 1 and a second transfer unit 122. The second transfer unit 122 is a transfer robot and can transfer the substrate W between the first transfer unit 112 and the plurality of processing units 1. In the example of FIG. 1, the processing block 120 also includes a placement unit 123. The placement unit 123 is, for example, a shelf that can place a plurality of substrates W in a vertically arranged state. The first transfer unit 112 places the unprocessed substrate W on the placement unit 123. The second transfer unit 122 takes out the unprocessed substrate W from the placement unit 123 and transfers the substrate W to the processing unit 1. The processing unit 1 processes the substrate W. The configuration of the processing unit 1 will be described later. The second transfer unit 122 takes out the processed substrate W from the processing unit 1 and transfers the substrate W to the placement unit 123. The first transfer unit 112 takes out the substrate W from the placement unit 123 and transfers the substrate W to the carrier C at the loading port 111. In the example of FIG. 1, a plurality of (for example, four) processing units 1 are arranged to surround the second transfer unit 122 in a plan view. The second transfer unit 122 can also be called a central robot. At each position in the plan view, the plurality of processing units 1 can be stacked in the vertical direction. That is, it can also be arranged such that a plurality of towers TW (four in the figure) formed by a plurality of processing units 1 stacked in the vertical direction surround the second transfer unit 122. The control unit 90 comprehensively controls the substrate processing apparatus 100. Specifically, the control unit 90 controls the first transfer unit 112, the second transfer unit 122, and the processing unit 1. FIG. 2 is a block diagram schematically showing an example of the internal configuration of the control unit 90. The control unit 90 is an electronic circuit and has, for example, a data processing unit 91 and a memory unit 92. In the specific example of FIG. 2, the data processing unit 91 and the memory unit 92 are connected to each other via a bus 93. The data processing unit 91 can be, for example, an arithmetic processing device such as a CPU (Central Processor Unit). The memory unit 92 can have a non-temporary memory unit (for example, ROM (Read Only Memory)) 921 and a temporary memory unit (for example, RAM (Random Access Memory)) 922. In the non-temporary memory unit 921, for example, a program that defines the processing to be executed by the control unit 90 can be stored. By causing the data processing unit 91 to execute this program, the control unit 90 can execute the processing defined in the program. Of course, part or all of the processing executed by the control unit 90 can also be executed by hardware such as a dedicated logic circuit. <Summary of the processing unit> Fig. 3 is a longitudinal sectional view schematically showing an example of the configuration of the processing unit 1 of the first embodiment. Note that it is not necessary for all the processing units 1 belonging to the substrate processing apparatus 100 to have the configuration illustrated in Fig. 3. It is sufficient if at least one of the processing units 1 of the substrate processing apparatus 100 has the configuration illustrated in Fig. 3. The processing unit 1 includes a substrate holding unit 2, at least one nozzle 3, and a substrate heating unit 40. In the example of Fig. 3, a chamber 10 is also provided in the processing unit 1. The chamber 10 has a box shape, and its internal space corresponds to a processing space for processing the substrate W. An openable and closable transfer port (not shown) is provided in the chamber 10. The second transfer unit 122 transfers the unprocessed substrate W into the chamber 10 through the transfer port, and transfers the processed substrate W out of the chamber 10 through the transfer port. In the example of Fig. 3, a fan filter unit 11 is provided at the top of the chamber 10. The fan filter unit 11 extracts the air outside the chamber 10, cleans it, and blows the cleaned air into the chamber 10. By the operation of the fan filter unit 11, a downflow of clean air is formed in the chamber 10. In the example of Fig. 3, the upstream end of an exhaust pipe 13 is connected to the lower part of the side wall of the chamber 10. The gas in the chamber 10 is discharged to the outside through the exhaust pipe 13. The substrate holding unit 2 is provided in the chamber 10, holds the substrate W in a horizontal posture, and rotates the substrate W about the rotation axis Q1. The horizontal posture described here means a posture in which the thickness direction of the substrate W is along the vertical direction. The rotation axis Q1 is an axis passing through the center of the substrate W and along the vertical direction. Such a substrate holding unit 2 may also be referred to as a rotating chuck. Here, the first main surface Wa of the substrate W on which the pattern is formed faces vertically upward. That is, in the example of Fig. 3, the first main surface Wa of the substrate W held by the substrate holding unit 2 corresponds to the upper surface. The pattern includes at least any one of, for example, a wiring pattern, an insulating pattern, and a semiconductor pattern. In the example of FIG. 3, the substrate holding unit 2 includes a rotating base 21, chuck pins 22, and a rotation driving unit 23. The rotating base 21 has a plate-like shape (for example, a disc shape) and is arranged in a posture with its thickness direction along the vertical direction. A plurality of chuck pins 22 are provided on the upper surface of the rotating base 21. The plurality of chuck pins 22 are arranged at equal intervals in the circumferential direction of the rotation axis Q1. The plurality of chuck pins 22 are arranged to be displaceable between a holding position and a releasing position described below. The holding position means the position where the chuck pins 22 abut against the periphery of the substrate W. By stopping the plurality of chuck pins 22 at each holding position, the substrate W is held by the plurality of chuck pins 22. In FIG. 3, the chuck pins 22 stopped at the holding position are shown. The releasing position means the position where each chuck pin 22 separates from the substrate W. By stopping the plurality of chuck pins 22 at each releasing position, the holding of the substrate W by the plurality of chuck pins 22 is released. The substrate holding unit 2 also includes a pin driving unit (not shown) for displacing the chuck pins 22. The pin driving unit includes a driving source such as a motor and a cylinder, for example, and is controlled by the control unit 90. The rotation driving unit 23 includes a shaft 231 and a motor 232. The upper end of the shaft 231 is connected to the lower surface of the rotating base 21, and the shaft 231 extends along the rotation axis Q1 from the lower surface of the rotating base 21. The motor 232 is controlled by the control unit 90 to rotate the shaft 231 around the rotation axis Q1. Thereby, the rotating base 21, the chuck pins 22, and the substrate W rotate integrally around the rotation axis Q1. In addition, the substrate holding unit 2 does not necessarily have the chuck pins 22. For example, the substrate holding unit 2 can also hold the substrate W by a chuck method such as a vacuum chuck, an electrostatic chuck, and a Bernoulli chuck. At least one nozzle 3 sprays a liquid onto the first main surface Wa of the substrate W held by the substrate holding unit 2. In the example of FIG. 3, since the first main surface Wa is the upper surface, the nozzle 3 is provided vertically above the substrate W held by the substrate holding unit 2. In the example of FIG. 3, nozzle 3c, nozzle 3w, and nozzle 3i are provided as the nozzle 3. The nozzle 3c sprays a chemical solution, the nozzle 3w sprays a cleaning solution, and the nozzle 3i sprays a drying solution. Specific examples of the chemical solution, the cleaning solution, and the drying solution will be described later. Hereinafter, the chemical solution, the cleaning solution, and the drying solution will also be collectively referred to as the processing solution. The nozzle 3 is, for example, a linear nozzle that sprays the processing solution in a continuously flowing state. In the example of FIG. 3, the nozzle 3 is arranged to be movable by a movement driving unit 35. In the example of FIG. 3, movement driving unit 35c, movement driving unit 35w, and movement driving unit 35i are shown as the movement driving unit 35. The movement driving unit 35c moves the nozzle 3c, the movement driving unit 35w moves the nozzle 3w, and the movement driving unit 35i moves the nozzle 3i. The moving drive unit 35c moves the nozzle 3c between the first processing position and the first standby position described below. The first standby position means the position where the nozzle 3c does not eject the chemical liquid onto the first main surface Wa of the substrate W, for example, a position radially outside the substrate holding unit 2. In the example of FIG. 3, the nozzle 3c stopped at the first standby position is shown. The first processing position means the position where the nozzle 3c ejects the chemical liquid onto the first main surface Wa of the substrate W, for example, a position vertically opposed to the central portion of the first main surface Wa of the substrate W. The moving drive unit 35w moves the nozzle 3w between the second processing position and the second standby position described below. The second processing position means the position where the nozzle 3w ejects the cleaning liquid onto the first main surface Wa of the substrate W, for example, a position vertically opposed to the central portion of the first main surface Wa of the substrate W. In the example of FIG. 3, the nozzle 3w stopped at the second processing position is shown. The second standby position means the position where the nozzle 3w does not eject the cleaning liquid onto the first main surface Wa of the substrate W, for example, a position radially outside the substrate holding unit 2. An example of the specific configuration of the moving drive unit 35w is shown in FIG. 3. In the example of FIG. 3, the moving drive unit 35w includes an arm 351, a support column 352, and a drive source 353. The support column 352 is provided radially outside a protection member 7 described later and extends in the vertical direction. The arm 351 extends in the horizontal direction, with its front end connected to the nozzle 3w and its base end connected to the support column 352. The drive source 353 is controlled by the control unit 90 to rotate the support column 352 around its central axis Q2 in a predetermined angular range in the forward and reverse directions. The drive source 353 includes, for example, a motor. When the support column 352 rotates around the central axis Q2 in a predetermined angular range in the forward and reverse directions, the nozzle 3w reciprocates along the circumference of the central axis Q2. The support column 352 is arranged such that the second processing position and the second standby position are located on the movement locus of the nozzle 3w. In addition, the moving drive unit 35w is not limited to the aspect of FIG. 3 and may include a linear motion mechanism such as a linear motor. The moving drive unit 35c may also have, for example, the same configuration as the moving drive unit 35w. The moving drive unit 35i moves the nozzle 3i between the shut-off processing position and the shut-off standby position described below. Further, in the example of FIG. 3, the nozzle 3i is integrally provided with a shut-off plate 6 described later, and the moving drive unit 35i moves the nozzle 3i and the shut-off plate 6 integrally. The shut-off processing position means the position where the nozzle 3i ejects the drying liquid onto the first main surface Wa of the substrate W, for example, the position facing the central portion of the first main surface Wa of the substrate W in the vertical direction. The shut-off standby position means the position where the nozzle 3i does not eject the drying liquid onto the first main surface Wa of the substrate W, for example, the position vertically above the shut-off processing position. In the example of FIG. 3, the nozzle 3i and the shut-off plate 6 stopped at the shut-off standby position are shown. Since the moving drive unit 35i moves the nozzle 3i in the vertical direction, it may also be referred to as a lifting drive unit. The moving drive unit 35i includes a drive source such as a motor, and a power transmission unit that transmits the power from the drive source to the nozzle 3i and the shut-off plate 6. The power transmission unit includes, for example, a cam mechanism or a ball screw mechanism. The nozzle 3 is connected to the downstream end of the supply pipe 31, and the upstream end of the supply pipe 31 is connected to the processing liquid supply source. In the example of FIG. 3, the supply pipes 31c, 31w, and 31i are shown as the supply pipe 31. The downstream end of the supply pipe 31c is connected to the nozzle 3c, and the upstream end of the supply pipe 31c is connected to the chemical liquid supply source. The chemical liquid supply source has a tank (not shown) for storing the chemical liquid, and supplies the chemical liquid to the upstream end of the supply pipe 31c. As the chemical liquid, for example, nitrous acid fluoride obtained by mixing hydrofluoric acid, nitric acid, and water, hydrofluoric acid hydrogen peroxide aqueous solution (FPM) obtained by mixing hydrofluoric acid, hydrogen peroxide, and water, tetramethylammonium hydroxide (TMAH), a mixed solution of sulfuric acid and hydrogen peroxide water (SPM), ammonia water, a mixed solution of ammonia, hydrogen peroxide, and water (SC-1), and a mixed solution of hydrogen chloride, hydrogen peroxide, and water (SC-2) and other liquids can be applied. Further, the chemical liquid may not be a mixed solution, but may also be a single liquid. For example, single liquids such as hydrofluoric acid (HF), hydrogen peroxide water, and sulfuric acid can be applied as the chemical liquid. The downstream end of the supply pipe 31w is connected to the nozzle 3w, and the upstream end of the supply pipe 31w is connected to the cleaning liquid supply source. The cleaning liquid supply source has a tank (not shown) for storing the cleaning liquid, and supplies the cleaning liquid to the upstream end of the supply pipe 31w. As the cleaning liquid, for example, pure water, carbon dioxide water, or ozone water can be applied. The downstream end of the supply pipe 31i is connected to the nozzle 3i, and the upstream end of the supply pipe 31i is connected to the drying liquid supply source. The drying liquid supply source has a tank (not shown) for storing the drying liquid, and supplies the drying liquid to the upstream end of the supply pipe 31i. As the drying liquid, for example, an organic solvent such as isopropyl alcohol can be applied. The surface tension of the drying liquid is lower than the surface tension of other processing liquids (for example, both the surface tension of the chemical liquid and the surface tension of the cleaning liquid). Also, the volatility of the drying liquid is higher than the volatility of other processing liquids (for example, both the volatility of the chemical liquid and the volatility of the cleaning liquid). A supply valve 32 and a flow rate adjustment valve 33 are interposed in a supply pipe 31. In the example of FIG. 3, a supply valve 32c and a flow rate adjustment valve 33c are interposed in a supply pipe 31c, a supply valve 32w and a flow rate adjustment valve 33w are interposed in a supply pipe 31w, and a supply valve 32i and a flow rate adjustment valve 33i are interposed in a supply pipe 31i. The supply valve 32 switches the opening and closing of the supply pipe 31. The flow rate adjustment valve 33 adjusts the flow rate of the processing liquid flowing through the supply pipe 31. The flow rate adjustment valve 33 may be a mass flow controller. The supply valve 32 and the flow rate adjustment valve 33 are controlled by a control unit 90. While the substrate holding unit 2 rotates the substrate W and the nozzle 3 is in the processing position, when the supply valve 32 is opened, the processing liquid is ejected from the nozzle 3 onto the first main surface Wa of the rotating substrate W. The processing liquid adhering to the first main surface Wa of the substrate W is subjected to the centrifugal force accompanying the rotation of the substrate W and flows radially outward along the first main surface Wa, and scatters to the outside from the periphery of the substrate W. Thereby, the first main surface Wa of the substrate W is subjected to processing corresponding to the type of the processing liquid. For example, when a cleaning chemical solution is ejected, the first main surface Wa of the substrate W is cleaned by the chemical solution. A substrate heating unit 40 heats the second main surface Wb of the substrate W held by the substrate holding unit 2. In the example of FIG. 3, the substrate heating unit 40 is provided at a position facing the second main surface Wb of the substrate W in the vertical direction. In the example of FIG. 3, since the second main surface Wb of the substrate W corresponds to the lower surface, the substrate heating unit 40 is provided directly below the substrate W. In the example of FIG. 3, the substrate heating unit 40 includes a nozzle 4. The nozzle 4 ejects a heat medium onto the second main surface Wb of the substrate W. In the example of FIG. 3, since the second main surface Wb of the substrate W corresponds to the lower surface, the nozzle 4 may also be referred to as a lower surface nozzle. In the example of FIG. 3, a through hole is formed at the center of the rotating base 21 of the substrate holding unit 2, and the shaft 231 is a hollow shaft. The through hole of the rotating base 21 and the hollow portion of the shaft 231 are connected in the vertical direction. A part of the nozzle 4 is disposed in the through hole. A jet outlet is formed on the upper surface of the nozzle 4, and the jet outlet of the nozzle 4 faces the center of the second main surface Wb of the substrate W in the vertical direction. The nozzle 4 ejects the heat medium onto the center of the second main surface Wb of the substrate W. The downstream end of a supply pipe 41 is connected to the nozzle 4. The supply pipe 41 extends inside the shaft 231 and penetrates the shaft 231. The upstream end of the supply pipe 41 is connected to a heat medium supply source. The heat medium is a fluid (gas or liquid), and as a more specific example, it is a liquid such as water. The heat medium supply source has, for example, a tank (not shown) for storing the heat medium, and supplies the heat medium to the upstream end of the supply pipe 41. In the example of FIG. 3, a supply valve 42, a flow control valve 43, and a heater 44 are provided in the supply pipe 41. The supply valve 42 switches the opening and closing of the supply pipe 41. The flow control valve 43 adjusts the flow rate of the heat medium flowing through the supply pipe 41. The flow control valve 43 may also be a mass flow controller. The heater 44 heats the heat medium flowing through the supply pipe 41. The heater 44 may be, for example, a resistive heater having a heating wire. The supply valve 42, the flow control valve 43, and the heater 44 are controlled by the control unit 90. When the supply valve 42 is opened, a high-temperature heat medium is ejected from the nozzle 4 toward the central portion of the second main surface Wb of the rotating substrate W. The heat medium deposited on the central portion of the second main surface Wb of the substrate W is subjected to a centrifugal force accompanying the rotation of the substrate W, flows along the second main surface Wb toward the radially outer side, and scatters outward from the periphery of the substrate W. When the high-temperature heat medium flows along the second main surface Wb of the substrate W, heat is transferred from the heat medium to the substrate W, and the substrate W is heated. In the example of FIG. 3, a protection member 7 and a protection member lifting drive unit 71 are provided in the processing unit 1. The protection member 7 has a cylindrical shape centered on the rotation axis Q1 and surrounds the substrate holding unit 2. The protection member 7 can catch the processing liquid and the heat medium scattered from the periphery of the substrate W. The protection member lifting drive unit 71 raises and lowers the protection member 7 between the upper position and the lower position described below. The upper position means a position where the upper end of the protection member 7 is vertically above the substrate W held by the substrate holding unit 2. In a state where the protection member 7 is located at the upper position, it can catch the processing liquid and the heat medium scattered from the periphery of the substrate W. The lower position is a position lower than the upper position, for example, a position where the upper end of the protection member 7 is vertically below the upper surface of the rotating base 21. In the example of FIG. 3, a plurality of protection members 7 are provided. The plurality of protection members 7 are arranged concentrically. The plurality of protection members 7 can be used separately according to the type of the processing liquid. In the example of FIG. 3, cups 72 corresponding to the respective protection members 7 are provided. The cup 72 has an annular (e.g., circular ring-shaped) recess (groove) surrounding the rotation axis Q1. Each cup 72 catches the processing liquid flowing down the inner peripheral surface of the corresponding protection member 7. The upstream end of the discharge pipe 12 is connected, for example, to the bottom of each cup 72. The processing liquid caught by each cup 72 is discharged to the outside of the processing unit 1 through the discharge pipe 12. In the example of FIG. 3, the processing unit 1 further includes a shielding plate 6. The shielding plate 6 is disposed at a position vertically opposed to the first main surface Wa of the substrate W held by the substrate holding portion 2. In the example of FIG. 3, since the first main surface Wa of the substrate W corresponds to the upper surface, the shielding plate 6 is disposed vertically above the substrate W. The shielding plate 6 has, for example, a plate-like shape and is disposed in a posture with its thickness direction along the vertical direction. The lower surface of the shielding plate 6 is an opposed surface opposed to the first main surface Wa of the substrate W. The shielding plate 6 has, for example, a circular shape in plan view. The diameter of the shielding plate 6 (i.e., the diameter of the opposed surface) can be, for example, 80% or more of the diameter of the substrate W, or 90% or more, or even the diameter of the substrate W or more. A through hole penetrating itself in the vertical direction is formed in the central portion of the shielding plate 6, and the nozzle 3i is disposed inside the through hole. In the example of FIG. 3, a hollow shaft 61 is disposed on the upper surface of the shielding plate 6. The hollow shaft 61 has a hollow portion that is connected to the through hole of the shielding plate 6 in the vertical direction. The diameter of the outer peripheral surface of the nozzle 3i is smaller than the diameters of the inner peripheral surfaces of the hollow shaft 61 and the shielding plate 6. The space between the outer peripheral surface of the nozzle 3i and the inner peripheral surfaces of the hollow shaft 61 and the shielding plate 6 functions as a gas flow path 3g as described later. In the example of FIG. 3, the upper portion of the hollow shaft 61 is connected to the downstream end of the supply pipe 31g. That is, the downstream end of the supply pipe 31g is connected to the gas flow path 3g between the outer peripheral surface of the nozzle 3i and the inner peripheral surfaces of the hollow shaft 61 and the shielding plate 6. The upstream end of the supply pipe 31g is connected to a gas supply source. The gas supply source has a storage portion (not shown) for storing an inert gas, and supplies the inert gas to the upstream end of the supply pipe 31g. The inert gas includes at least one of, for example, nitrogen gas and noble gases. The noble gases include, for example, argon gas. A supply valve 32g, a flow rate adjustment valve 33g, and a heater 34g are provided in the supply pipe 31g. The supply valve 32g switches the opening and closing of the supply pipe 31g. The flow rate adjustment valve 33g adjusts the flow rate of the inert gas flowing through the supply pipe 31g. The heater 34g heats the inert gas flowing through the supply pipe 31g. The heater 34g can also be, for example, a resistive heater having a heating wire. The supply valve 32g, the flow rate adjustment valve 33g, and the heater 34g are controlled by the control unit 90. When the supply valve 32g is opened and the heater 34g is actuated, the high-temperature inert gas is ejected from the central portion of the lower surface of the shielding plate 6 (i.e., the lower port of the gas flow path 3g) toward the central portion of the first main surface Wa of the substrate W. Thereby, drying of the substrate W can be promoted. <Example of the operation of the substrate processing apparatus> Next, an example of the operation of the processing unit 1 will be described. FIG. 4 is a flowchart showing an example of the operation of the processing unit 1. The control unit 90 causes the processing unit 1 to execute the processes of steps S1 to S7 according to a preset processing sequence (process recipe). FIGS. 5 and 6 are diagrams schematically showing an example of the state of the processing unit 1 in each step. First, the second transfer unit 122 transfers the substrate W to the processing unit 1. Then, the substrate holding unit 2 holds the substrate W received from the second transfer unit 122 (step S1: holding process). As a specific example, the substrate holding unit 2 moves a plurality of chuck pins 22 from their respective release positions to the holding positions. Thereby, the plurality of chuck pins 22 hold the substrate W. The substrate holding unit 2 continuously holds the substrate W until the processing of the substrate W is completed. Next, the substrate holding unit 2 starts rotating the substrate W (step S2: rotation start process). The substrate holding unit 2 can continuously rotate the substrate W until the processing of the substrate W is completed. Next, the processing unit 1 supplies a chemical solution to the first main surface Wa of the substrate W (step S3: chemical solution process). First, the movement drive unit 35c moves the nozzle 3c to the first processing position. Also, the protection member lifting drive unit 71 raises the protection member 7 for the chemical solution to the upper position. Then, the control unit 90 opens the supply valve 32c. That is, the control unit 90 switches the supply valve 32c from the closed state to the open state. Thereby, the chemical solution is ejected from the nozzle 3c onto the first main surface Wa of the rotating substrate W. The chemical solution adhering to the first main surface Wa of the substrate W flows radially outward due to the centrifugal force accompanying the rotation of the substrate W and scatters from the periphery of the substrate W. At this time, by causing the chemical solution to act on the first main surface Wa of the substrate W, a chemical solution process corresponding to the type of the chemical solution is performed on the first main surface Wa of the substrate W. For example, the processing unit 1 performs a cleaning process for washing and removing impurities on the first main surface Wa of the substrate W, or an etching process for etching a predetermined film on the first main surface Wa of the substrate W. The chemical solution scattered from the periphery of the substrate W is caught by the protection member 7 and discharged to the outside of the chamber 10 through the discharge pipe 12. When the processing of the substrate W is sufficiently performed, the control unit 90 closes the supply valve 32c. As a specific example, the control unit 90 measures the elapsed time since the start of the ejection of the chemical solution and determines whether the elapsed time is equal to or longer than a predetermined chemical solution time. The chemical solution time is preset to a time sufficient for performing the chemical solution process. The measurement of the elapsed time is performed by, for example, a timer circuit (not shown) belonging to the control unit 90. When the elapsed time is equal to or longer than the chemical solution time, the control unit 90 switches the supply valve 32c from the open state to the closed state. Also, after closing the supply valve 32c, the movement drive unit 35c moves the nozzle 3c to the first standby position. Next, the processing unit 1 supplies a cleaning liquid to the first main surface Wa of the substrate W (step S4: cleaning process). Specifically, first, the movement driving unit 35w moves the nozzle 3w to the second processing position. Also, when the protective member 7 for the cleaning liquid is different from the protective member 7 for the chemical liquid, the protective member lifting driving unit 71 appropriately lifts and lowers the protective member 7 so that the protective member 7 for the cleaning liquid is in the upper position. Then, the control unit 90 opens the supply valve 32w. That is, the control unit 90 switches the supply valve 32w from the closed state to the open state. Thereby, as shown in FIG. 5(a), the cleaning liquid is ejected from the nozzle 3w onto the first main surface Wa of the rotating substrate W. The cleaning liquid adhering to the first main surface Wa of the substrate W flows radially outward due to the centrifugal force accompanying the rotation of the substrate W and scatters from the periphery of the substrate W. At this time, the cleaning liquid flushes the chemical liquid on the first main surface Wa of the substrate W radially outward. Thereby, the processing liquid on the first main surface Wa of the substrate W is replaced from the chemical liquid with the cleaning liquid. The processing liquid scattered from the periphery of the substrate W is caught by the protective member 7 and discharged to the outside of the chamber 10 through the discharge pipe 12. When the replacement from the chemical liquid to the cleaning liquid is sufficiently performed, the control unit 90 closes the supply valve 32w. As a specific example, the control unit 90 measures the elapsed time since the start of the ejection of the cleaning liquid, and when the elapsed time is equal to or longer than a specified cleaning time, switches the supply valve 32w from the open state to the closed state. The cleaning time is preset to a time sufficient for the replacement from the chemical liquid to the cleaning liquid. Also, after the supply valve 32w is closed, the movement driving unit 35w moves the nozzle 3w to the second standby position. Next, the processing unit 1 supplies a drying liquid to the first main surface Wa of the substrate W (step S5: drying liquid supply process). Specifically, first, the movement driving unit 35i moves the nozzle 3i and the shutter 6 integrally to the shutter processing position. Also, when the protective member 7 for the drying liquid is different from the protective member 7 for the cleaning liquid, the protective member lifting driving unit 71 appropriately lifts and lowers the protective member 7 so that the protective member 7 for the drying liquid rises to the upper position. Then, the control unit 90 opens the supply valve 32i. That is, the control unit 90 switches the supply valve 32i from the closed state to the open state. When the supply valve 32i is opened, as shown in FIG. 5(b), the drying liquid is ejected from the nozzle 3i onto the first main surface Wa of the rotating substrate W. The temperature of the drying liquid can be, for example, room temperature (e.g., around 25 degrees Celsius). The drying liquid adhering to the first main surface Wa of the substrate W flows radially outward due to the centrifugal force accompanying the rotation of the substrate W and scatters from the periphery of the substrate W. At this time, the cleaning liquid on the first main surface Wa of the substrate W is flushed by the drying liquid, and the processing liquid on the first main surface Wa of the substrate W is replaced from the cleaning liquid with the drying liquid. The processing liquid scattered from the periphery of the substrate W is caught by the protection member 7 and discharged to the outside of the chamber 10 through the discharge pipe 12. The rotational speed of the substrate W in the drying liquid supply process can be set to, for example, 150 rpm or more and 600 rpm or less, or can also be set to 200 rpm or more and 400 rpm or less. As a more specific example, the rotational speed can be set to 300 rpm. Further, the processing unit 1 can also heat the substrate W when supplying the drying liquid. That is, the substrate heating unit 40 can heat the second main surface Wb of the substrate W. As a more specific example, the control unit 90 can open the supply valve 42 and activate the heater 44. Thereby, as shown in FIG. 5(b), the high-temperature heat medium (e.g., warm water) is ejected from the nozzle 4 onto the second main surface Wb of the rotating substrate W. The heater 44 can heat the temperature of the heat medium to, for example, 60 degrees Celsius or more, or can also be heated to 70 degrees Celsius or more, and can further be heated to 80 degrees Celsius or more. Further, the heater 44 can also adjust the temperature of the heat medium to, for example, not reaching the boiling point of the drying liquid. The temperature of the heat medium described here means, for example, the temperature of the heat medium at the ejection port of the nozzle 4. The flow rate adjustment valve 43 can also adjust the flow rate of the heat medium to, for example, a value greater than the flow rate of the drying liquid. More specifically, the flow rate adjustment valve 43 can adjust the flow rate of the heat medium to 1000 mL (milliliters) / min or more, or can also be adjusted to 1500 mL / min or more. The heat medium adhering to the central portion of the second main surface Wb of the substrate W flows radially outward due to the centrifugal force accompanying the rotation of the substrate W and scatters from the periphery of the substrate W. When the high-temperature heat medium flows along the second main surface Wb of the substrate W, heat is transferred from the heat medium to the substrate W, and the substrate W is heated. The heat of the substrate W is transferred to the drying liquid on the first main surface Wa. Therefore, the drying liquid on the first main surface Wa of the substrate W is also heated and its temperature rises. After the replacement of the self-cleaning liquid with the drying liquid is sufficiently performed, the processing unit 1 dries the substrate W (Step S6: Drying process). Specifically, the processing unit 1 measures the elapsed time since the start of the ejection of the drying liquid, and determines whether the elapsed time is equal to or longer than a specified drying liquid supply time. The drying liquid supply time is set in advance to a time sufficient for the replacement of the self-cleaning liquid with the drying liquid. The drying liquid supply time is set to, for example, about several tens of seconds, and specifically, it can be set to about 40 seconds. Then, when the elapsed time is equal to or longer than the drying liquid supply time, the processing unit 1 dries the substrate W. Specifically, the control unit 90 closes the supply valve 32i, opens the supply valve 32g, activates the heater 34g, causes the movement drive unit 35i to lower the shutter 6 to a drying position closer to the substrate W than the shut-off processing position, and causes the substrate holding unit 2 to increase the rotation speed of the substrate W. When the supply valve 32g is opened, as shown in FIG. 6(a), the high-temperature inert gas is ejected from the gas ejection port at the center of the lower surface of the shutter 6 (i.e., the lower port of the gas flow path 3g) toward the first main surface Wa of the substrate W. In FIG. 6, the flow direction of the inert gas is schematically shown by the arrow directly below the shutter 6. The heater 34g can heat the temperature of the inert gas to, for example, 60 degrees Celsius or higher, or can be heated to 70 degrees Celsius or higher, or can also be heated to 80 degrees Celsius or higher. The temperature of the inert gas can be, for example, the temperature of the inert gas at the gas ejection port of the gas flow path 3g. The flow rate adjustment valve 33g can adjust the flow rate of the inert gas to, for example, 10 L (liters) / min or higher and 300 L / min or lower. In FIG. 6(a), the lowering of the shutter 6 is schematically shown by the framed arrow marked beside the shutter 6. Here, the movement drive unit 35i lowers the nozzle 3i and the shutter 6 integrally in a state where the inert gas is ejected from the gas flow path 3g. When the shutter 6 is lowered to the drying position, as shown in FIG. 6(b), the interval between the shutter 6 and the first main surface Wa of the substrate W can be narrowed. That is, the interval between the shutter 6 and the substrate W in the drying process can be made narrower than the interval between the shutter 6 and the substrate W in the drying liquid supply process. Therefore, in the drying process, the flow velocity of the inert gas flowing out from the periphery of the shutter 6 and the substrate W to the outside in the radial direction can be increased. The interval between the lower surface of the shutter 6 and the first main surface Wa of the substrate W in the drying process is set to, for example, about several mm (for example, 5 mm) or less. When transitioning from the drying liquid supply process to the drying process and at the initial stage of the drying process, the substrate holding unit 2 can increase the rotation speed of the substrate W monotonically without decreasing it. For example, the substrate holding unit 2 can rotate the substrate W at a rotation speed of 800 rpm or more and 2500 rpm or less, and can also rotate the substrate W at a rotation speed of 800 rpm or more and 1500 rpm or less. Further, the substrate holding unit 2 can also gradually (for example, stepwise) increase the rotation speed of the substrate W during the descending period or after the descent of the shutter 6. By increasing the rotation speed, the amount of drying liquid scattered from the periphery of the substrate W can be increased. Therefore, the drying liquid can be evaporated in a state where the liquid film of the drying liquid on the first main surface Wa is thinned. Therefore, the drying liquid can be evaporated in a shorter time. On the other hand, when the rotation speed of the substrate W increases, the heat medium easily winds from the second main surface Wb of the substrate W to the peripheral portion of the first main surface Wa via the periphery. However, in the above example, the inert gas flows out from between the shutter 6 and the substrate W to the outside in the radial direction at a relatively high flow rate. Therefore, the inert gas can push the heat medium back to the outside in the radial direction. Therefore, the winding of the heat medium can be suppressed or prevented. In other words, the interval between the shutter 6 and the substrate W and the flow rate of the inert gas can be set to a level that can sufficiently suppress the winding of the heat medium. When the drying liquid has evaporated sufficiently, the substrate heating unit 40 stops heating the substrate W. As a specific example, the control unit 90 measures the elapsed time since the ejection of the drying liquid stopped, and determines whether the measured time is equal to or longer than a specified evaporation time. The evaporation time is preset to a time when the first main surface Wa of the substrate W is sufficiently dried. When the elapsed time is equal to or longer than the evaporation time, the control unit 90 switches the supply valve 42 from the open state to the closed state. Thereby, the supply of the heat medium to the second main surface Wb of the substrate W is stopped. That is, the heating of the substrate W by the substrate heating unit 40 is stopped. Then, for example, when the control unit 90 has elapsed a specified drying time sufficient to dry the second main surface Wb of the substrate W, the control unit 90 stops the rotation of the substrate W. Further, the moving drive unit 35i integrally raises the nozzle 3i and the shutter 6 to the shutter standby position, and the protection member lifting drive unit 71 lowers the protection member 7 to the lower position. Next, the holding of the substrate W by the substrate holding unit 2 is released (step S7: holding release process). Then, the second transfer unit 122 transfers the processed substrate W out of the processing unit 1. As described above, the processing unit 1 can process the substrate W. And, in the present embodiment, after the supply of the drying liquid is stopped, the substrate heating unit 40 heats the second main surface Wb of the substrate W (drying process, FIG. 6). Therefore, in the drying process, the drying liquid on the first main surface Wa of the substrate W can be evaporated at a higher temperature. FIG. 7 is a diagram schematically showing a timing chart of the processing unit 1 and an example of the temporal change in the temperature of the first main surface Wa of the substrate W (hereinafter referred to as the substrate temperature). In the example of FIG. 7, at time point t1, the control unit 90 switches the supply valve 32i and the supply valve 42 from the closed state to the open state. Therefore, at time point t1, the nozzle 3i starts ejecting the drying liquid, and the nozzle 4 starts ejecting the high-temperature heat medium. By the ejection of this drying liquid, the substantial drying liquid supply process (step S5) starts. Also, by the ejection of the heat medium, the substrate temperature of the first main surface Wa of the substrate W rises with the passage of time. The substrate temperature can rise at a relatively high rising rate to a certain extent, and then rises slowly or converges. In the example of FIG. 7, at time point t2, which is after time point t1, the control unit 90 switches the supply valve 32i from the open state to the closed state. Therefore, at time point t2, the ejection of the drying liquid stops. By the stop of the ejection of this drying liquid, the drying liquid supply process substantially ends. On the other hand, in the example of FIG. 7, even after time point t2, the supply valve 42 remains open. Therefore, during the evaporation time after time point t2 (the time from time point t2 to time point t3 in FIG. 7: corresponding to the specified period), the nozzle 4 ejects the heat medium, and the substrate W continuously receives heat from the heat medium. Therefore, the substrate temperature of the first main surface Wa of the substrate W during the evaporation time can be made equal to or higher than the substrate temperature when the drying liquid is supplied. In the example of FIG. 7, after time point t2, the temperature of the first main surface Wa of the substrate W rises. The reason is that after time point t2, no new drying liquid is supplied to the first main surface Wa of the substrate W. That is, if a drying liquid having a temperature lower than that of the heat medium is supplied to the first main surface Wa, the drying liquid cools the substrate W, and the supply of the drying liquid ends after time point t2, so the substrate W warms up. Therefore, the substrate temperature of the first main surface Wa of the substrate W during the evaporation time is higher than the substrate temperature of the first main surface Wa of the substrate W during the drying liquid supply process. The temperature of the first main surface Wa of the substrate W can be considered to be approximately equal to the temperature of the drying liquid on the first main surface Wa. Therefore, the temperature of the drying liquid during the evaporation time is also higher than the temperature of the drying liquid during the drying liquid supply process. Also, the higher the temperature of the drying liquid, the lower the surface tension of the drying liquid. As described above, since the temperature of the drying liquid during the evaporation time is relatively high, the surface tension of the drying liquid during the evaporation time can be reduced. Also, the evaporation speed of the drying liquid can be increased. The higher the surface tension of the drying liquid, the more likely it is for the pattern to collapse. Also, the lower the evaporation speed, the more likely it is for the pattern to collapse. The reason is that the lower the evaporation speed, the greater the force product of the surface tension acting on the pattern. According to the present embodiment, the surface tension of the drying liquid can be reduced while the evaporation speed is increased, so the collapse rate of the pattern can be effectively reduced. In the example of FIG. 7, at time point t3 after time point t2, the control unit 90 switches the supply valve 42 from the open state to the closed state. Therefore, at time point t3, the nozzle 4 stops ejecting the heat medium. That is, the substrate heating unit 40 stops heating the second main surface Wb of the substrate W at time point t3. Therefore, after time point t3, the temperature of the first main surface Wa of the substrate W decreases with the passage of time. Also, in the above example, in the drying process (step S6), high-temperature inert gas is supplied to the first main surface Wa of the substrate W. Therefore, the temperature of the drying liquid on the first main surface Wa of the substrate W in the drying liquid can be further increased, and evaporation can be further promoted. Therefore, the collapse rate of the pattern can be further reduced. Also, the temperature distribution of the drying liquid on the first main surface Wa of the substrate W can be made uniform. Also, in the above example, in the drying process, the substrate holding unit 2 increases the rotation speed of the substrate W. Therefore, the amount of the drying liquid scattered from the periphery of the substrate W to the outside can be increased, and the evaporation of the drying liquid can be further promoted. That is, the liquid film of the drying liquid on the first main surface Wa is thinned by scattering, and the evaporation of the drying liquid is promoted. Thereby, the collapse rate of the pattern can be further reduced. Also, in the above example, in the drying process, the moving drive unit 35i moves the shutter 6 to a drying position closer to the first main surface Wa than the shut-off processing position. Therefore, the interval between the shutter 6 and the substrate W can be further narrowed, and the flow rate of the inert gas flowing out from between the shutter 6 and the substrate W to the radially outer side can be increased. Therefore, the recirculation of the heat medium at the periphery of the substrate W can be suppressed or prevented. Thereby, the collapse rate of the pattern at the peripheral portion of the first main surface Wa of the substrate W can be reduced, and also, the adhesion of fine particles to the peripheral portion can be suppressed. On the contrary, in the drying liquid supply process, the shutter 6 stops at the shut-off processing position farther from the substrate W than the drying position. Therefore, even if the drying liquid ejected from the nozzle 3i rebounds on the first main surface Wa of the substrate W, the possibility that the rebounded drying liquid adheres to the lower surface of the shutter 6 can be reduced. When the drying liquid adheres to the lower surface of the shutter 6, for example, at the time of processing the next substrate W, the liquid droplets of the adhered drying liquid may fall onto the first main surface Wa of the substrate W. This may cause processing defects, which is not good. As described above, if the shutter 6 is stopped at the shut-off processing position in the drying liquid supply process, such defects can be suppressed. Further, in the above example, in the drying liquid supply step, the substrate heating unit 40 heats the second main surface Wb of the substrate W, and also heats the second main surface Wb of the substrate W when transitioning from the drying liquid supply step to the drying step. That is, the substrate heating unit 40 continuously heats the second main surface Wb of the substrate W in the drying liquid supply step and the initial stage of the drying step. Thereby, at the start point of the drying step (i.e., time point t2), the temperature of the first main surface Wa of the substrate W can be maintained higher. That is, the temperature of the drying liquid can be increased from the start point of the drying step. Therefore, in the drying step, the evaporation rate of the drying liquid can be increased more rapidly, and the collapse rate of the pattern can be reduced more appropriately. Further, in the drying liquid supply step, by increasing the temperature of the drying liquid on the first main surface Wa of the substrate W, the replacement efficiency from the cleaning liquid to the drying liquid can also be increased. That is, the residue of the cleaning liquid with a surface tension larger than that of the drying liquid can be suppressed. Therefore, the collapse rate of the pattern in the drying step can be further reduced. <Second Embodiment> The configuration of the processing unit 1 of the second embodiment is the same as that of the first embodiment except for the specific configuration of the substrate heating unit 40. FIG. 8 is a diagram schematically showing an example of the configuration of the substrate heating unit 40 of the second embodiment. In the example of FIG. 8, the substrate heating unit 40 includes a nozzle 4, a common pipe 411, a first temperature pipe 412, a second temperature pipe 413, and a mixing unit 45. The downstream end of the common pipe 411 is connected to the nozzle 4, and the upstream end of the common pipe 411 is connected to the mixing unit 45. The downstream ends of the first temperature pipe 412 and the second temperature pipe 413 are also connected to the mixing unit 45. The upstream ends of the first temperature pipe 412 and the second temperature pipe 413 are connected to a heat medium supply source. A heat medium with a first medium temperature flows in the first temperature pipe 412, and a heat medium with a second medium temperature flows in the second temperature pipe 413. The second medium temperature is lower than the first medium temperature. Hereinafter, the heat medium with a first medium temperature flowing through the first temperature pipe 412 is also referred to as a high-temperature heat medium, and the heat medium with a second medium temperature flowing through the second temperature pipe 413 is also referred to as a low-temperature heat medium. In the example of FIG. 8, a heater 44 is provided in the first temperature pipe 412. The heater 44 heats the high-temperature heat medium flowing through the first temperature pipe 412 so that the temperature of the heat medium becomes the first medium temperature. The second medium temperature can be room temperature. Alternatively, a heater (not shown) can also be provided in the second temperature pipe 413 to heat the low-temperature heat medium to a second medium temperature higher than room temperature. The mixing unit 45 mixes the high-temperature heat medium from the first temperature pipe 412 and the low-temperature heat medium from the second temperature pipe 413 at a variable mixing ratio, and causes the mixed heat medium to flow into the common pipe 411. The mixing ratio of the mixing unit 45 is controlled by the control unit 90. In the example of FIG. 8, the mixing unit 45 includes a multi-way valve 451, a flow control valve 452, and a flow control valve 453. The flow control valve 452 adjusts the flow rate of the high-temperature heat medium flowing through the first temperature pipe 412. The flow control valve 453 adjusts the flow rate of the low-temperature heat medium flowing through the second temperature pipe 413. The flow control valve 452 and the flow control valve 453 are controlled by the control unit 90. The control unit 90 can adjust the mixing ratio by adjusting each flow rate. The multi-way valve 451 switches the connection and non-connection between the common pipe 411 and the first temperature pipe 412, and switches the connection and non-connection between the common pipe 411 and the second temperature pipe 413. In addition, when the multi-way valve 451 itself has a function of adjusting the flow rate, the flow control valve 452 and the flow control valve 453 are not required. In the example of FIG. 8, a supply valve 42 is provided in the common pipe 411. The supply valve 42 switches the opening and closing of the common pipe 411. The supply valve 42 is controlled by the control unit 90. <Example of operation of substrate processing apparatus> The operation of the processing unit 1 of the second embodiment is as shown in FIG. 4 referred to in the first embodiment. However, the specific operation of the substrate heating unit 40 is different from that of the first embodiment. In the second embodiment, the substrate heating unit 40 heats the substrate W in the drying process (step S6) with a second heat quantity per unit time that is larger than the first heat quantity per unit time in the drying liquid supply process (step S5). As a more specific example, the substrate heating unit 40 supplies a heat medium to the substrate W in the drying process, the temperature of which is higher than the temperature of the heat medium supplied to the substrate W in the drying liquid supply process. Specifically, the substrate heating unit 40 adjusts the mixing ratio of the high-temperature heat medium and the low-temperature heat medium, and supplies a heat medium having a higher temperature than the heat medium in the drying liquid supply process to the second main surface of the substrate W in the drying process. FIG. 9 is a diagram schematically showing an example of the time change of the timing chart, the flow rate of the heat medium, and the temperature of the heat medium of the processing unit 1 of the second embodiment. In the example of FIG. 9, an example of the flow rate of the high-temperature heat medium is shown by a curve G1, and an example of the flow rate of the low-temperature heat medium is shown by a curve G2. In the example of FIG. 9, the flow rate of the high-temperature heat medium is constant during the period from time point t1 to time point t3. On the other hand, the flow rate of the low-temperature heat medium decreases at time point t2. That is, the flow rate of the low-temperature heat medium during the evaporation time from time point t2 to time point t3 is smaller than the flow rate of the low-temperature heat medium in the drying liquid supply process from time point t1 to time point t2. Therefore, the temperature of the heat medium ejected from the nozzle 4 during the evaporation time is higher than the temperature of the heat medium ejected from the nozzle 4 in the drying liquid supply process. In addition, in the second embodiment, the temperature of the heat medium ejected from the nozzle 4 only needs to be higher than that in the drying liquid supply step (step S6) in the drying step, so the flow rates of the high-temperature heat medium and the low-temperature heat medium are not limited to the above. In short, as long as the ratio of the flow rate of the high-temperature heat medium to the flow rate of the low-temperature heat medium (= flow rate of high-temperature heat medium / flow rate of low-temperature heat medium) is higher in the drying step than in the drying liquid supply step. In the drying liquid supply step, the temperature of the heat medium ejected from the nozzle 4 can be adjusted to be lower than the boiling point bp of the drying liquid. When the drying liquid is isopropyl alcohol, the boiling point bp of the drying liquid is about 82.4 degrees Celsius. In this case, the temperature of the heat medium in the drying liquid supply step can be adjusted to be lower than 82.4 degrees Celsius. As a specific example, the first medium temperature of the high-temperature heat medium is set to a value greater than the boiling point bp of the drying liquid (for example, 85 degrees Celsius), and the second medium temperature of the low-temperature heat medium is set to a value less than the boiling point pb of the drying liquid (for example, room temperature). Moreover, the mixing unit 45 mixes the high-temperature heat medium and the low-temperature heat medium at a mixing ratio such that the temperature of the heat medium is lower than the boiling point bp of the drying liquid. Thereby, since the temperature of the heat medium ejected from the nozzle 4 is lower than the boiling point bp of the drying liquid, the drying liquid on the first main surface Wa of the substrate W also does not reach the boiling point bp. Therefore, boiling of the drying liquid on the first main surface Wa of the substrate W during the drying liquid supply can be more reliably suppressed. If the drying liquid on the first main surface Wa of the substrate W boils during the supply of the drying liquid, a large amount of fine particles will adhere to the first main surface Wa of the substrate W. In this embodiment, adhesion of such fine particles can be more reliably suppressed. On the other hand, in the drying step, ejection of the drying liquid from the nozzle 3i is stopped. Therefore, even if the drying liquid on the first main surface Wa of the substrate W boils, almost no fine particles will adhere. Therefore, the substrate heating unit 40 can also adjust the temperature of the heat medium during the evaporation time from time point t2 to time point t3 to be equal to or higher than the boiling point bp of the drying liquid. That is, the mixing unit 45 can also adopt a mixing ratio such that the temperature of the heat medium is equal to or higher than the boiling point bp of the drying liquid. In the example of FIG. 9, the flow rate of the low-temperature heat medium is set to zero. In addition, the mixing unit 45 can also gradually change the mixing ratio over time. For example, during the descending time when the shutter 6 descends from the shut-off position to the drying position, the mixing unit 45 can gradually change the mixing ratio. As described above, in the second embodiment, the temperature of the heat medium in the drying step is higher than the temperature of the heat medium in the drying liquid supply step. Therefore, the temperature of the substrate W and the drying liquid in the drying step can be further increased. Therefore, the evaporation rate of the drying liquid can be further increased in the drying step. Therefore, the collapse rate of the pattern on the substrate W can be further reduced. Conversely, the temperature of the substrate W and the drying liquid in the drying liquid supply process can be made lower than that in the drying process. Therefore, boiling of the drying liquid on the first main surface Wa of the substrate W in the drying liquid supply process can be suppressed or prevented, and adhesion of fine particles to the first main surface Wa can be suppressed. Further, in the above example, the substrate heating unit 40 changes the temperature of the heat medium ejected from the nozzle 4 by changing the mixing ratio of the mixing unit 45. Thereby, the temperature of the heat medium can be changed rapidly. Therefore, at the initial stage of the drying process, the temperature of the heat medium can be raised more rapidly, and the evaporation rate of the drying liquid can be increased more rapidly. Thereby, the collapse rate of the pattern can also be further reduced. <Third Embodiment> In the first and second embodiments, the substrate heating unit 40 starts heating the second main surface Wb of the substrate W (see FIGS. 7 and 9) almost simultaneously with the start of ejection of the drying liquid from the nozzle 3i in the drying liquid supply process (step S5). However, it is not limited thereto. The substrate heating unit 40 may also start heating the second main surface Wb of the substrate W at a time point later than the start time point of ejection of the drying liquid from the nozzle 3i. FIG. 10 is a diagram schematically showing a timing chart of the processing unit 1 of the third embodiment and an example of the temperature change of the first main surface Wa of the substrate W. In the example of FIG. 10, the control unit 90 switches the supply valve 32i from the closed state to the open state at the time point t1. Thereby, the drying liquid starts to be ejected from the nozzle 3i onto the first main surface Wa of the substrate W. That is, at the time point t1, the substantial drying liquid supply process starts. On the other hand, in the example of FIG. 10, the control unit 90 switches the supply valve 42 from the closed state to the open state at the time point t12 later than the time point t1. Thereby, the high-temperature heat medium starts to be ejected from the nozzle 4 onto the second main surface Wb of the substrate W. That is, the substrate heating unit 40 starts heating the second main surface Wb of the substrate W. Then, the control unit 90 switches the supply valve 32i from the open state to the closed state at the time point t2 after the time point t12. That is, at the time point t2, the substantial drying liquid supply process ends. In summary, during the drying liquid supply time T from the time point t1 to the time point t2, the substrate heating unit 40 does not heat the second main surface Wb of the substrate W within the specified previous time T1 from the time point t1 to the time point t12, and heats the second main surface Wb of the substrate W within the specified subsequent time T2 from the time point t12 to the time point t2. The drying liquid supply time T is set to be 20 seconds or more, and as a specific example, it can be set to about 40 seconds. The subsequent time T2 is preset to be a time such that the temperature of the first main surface Wa of the substrate W at the time point t2 is sufficiently close to the boiling point of the drying liquid. For example, the subsequent time T2 can be set to be less than half of the drying liquid supply time T, or can be set to be less than one-third of the drying liquid supply time T, or can be set to be less than one-fourth of the drying liquid supply time T, or can be set to be less than one-tenth of the drying liquid supply time T. As described above, in the third embodiment, the substrate heating unit 40 does not heat the substrate W during the previous time T1, and heats the second main surface Wb of the substrate W during the subsequent time T2. That is, the substrate heating unit 40 heats the second main surface Wb of the substrate W only during the subsequent time T2. Therefore, the operation time of the substrate heating unit 40 can be shortened, and the power consumption of the substrate processing apparatus 100 can be reduced. Further, when the substrate heating unit 40 supplies a high-temperature heat medium to the second main surface Wb of the substrate W, the supply amount of the heat medium can be reduced. When the heat medium is a liquid, liquefaction saving can be achieved. <Fourth Embodiment> The configuration of the processing unit 1 in the fourth embodiment is the same as that in the second embodiment, for example. In the fourth embodiment, in the drying liquid supply step (step S5), the substrate heating unit 40 sets the temperature of the heat medium to be equal to or higher than the boiling point bp of the drying liquid. FIG. 11 is a diagram schematically showing an example of the time changes of the timing chart of the processing unit 1 in the fourth embodiment, the flow rate of the heat medium, the temperature of the heat medium, and the temperature of the first main surface Wa of the substrate W. In the example of FIG. 11, in the drying liquid supply step (step S5), the temperature of the heat medium ejected from the nozzle 4 is higher than the boiling point bp of the drying liquid. When the drying liquid is isopropyl alcohol, the boiling point bp is 82.4 degrees Celsius, and the temperature of the heat medium is set to about 85 degrees Celsius, for example. However, the temperature of the heat medium can be set to be lower than the boiling point of the heat medium. For example, when the heat medium is water, it can be set to 90 degrees Celsius, which is 10 degrees lower than the boiling point (100 degrees Celsius). Thereby, the SEMI (Semiconductor Equipment and Materials International) standard can be complied with. In the drying liquid supply step, the drying liquid having a temperature lower than that of the heat medium is ejected from the nozzle 3i. The drying liquid continuously adhering to the low-temperature first main surface Wa of the substrate W can cool the first main surface Wa of the substrate W. The greater the flow rate of the drying liquid, the higher the cooling ability of the drying liquid. Therefore, the flow rate adjustment valve 33i adjusts the flow rate of the drying liquid to a value at which the substrate temperature of the first main surface Wa of the substrate W does not reach the boiling point bp. Specifically, the flow rate of the drying liquid is preset to be, for example, 250 ml / min or more. In the example of FIG. 11, the temperature of the central portion in the first main surface Wa of the substrate W is shown as the substrate temperature. Since the high-temperature heat medium adheres to the central portion of the second main surface Wb of the substrate W, the substrate temperature has the temperature distribution described below. That is, the substrate temperature is higher at the central portion of the substrate W and decreases as it moves toward the outer diameter side. Therefore, in the example of FIG. 11, the highest value in the temperature distribution of the first main surface Wa of the substrate W is shown as the substrate temperature. As shown in FIG. 11, the temperature of the substrate in the drying liquid supply process does not reach the boiling point bp of the drying liquid. When the drying liquid is isopropyl alcohol, the highest substrate temperature in the temperature distribution of the substrate W can be adjusted to, for example, about 80 degrees Celsius or less. Therefore, boiling of the drying liquid in the drying liquid supply process can be more reliably suppressed. Furthermore, adhesion of fine particles to the first main surface Wa of the substrate W can be more reliably suppressed. Moreover, in the fourth embodiment, the temperature of the heat medium in the drying liquid supply process is equal to or higher than the boiling point bp. Therefore, in the drying liquid supply process, the maximum value of the temperature distribution of the first main surface Wa of the substrate W can be made closer to the boiling point bp. The minimum value of the temperature distribution of the first main surface Wa of the substrate W in the drying liquid supply process (i.e., the substrate temperature at the peripheral portion of the first main surface Wa) is, for example, 60 degrees Celsius or higher. That is, the flow rate of the drying liquid can be set such that the substrate temperature of the first main surface Wa of the substrate W is 60 degrees Celsius or higher and does not reach the boiling point bp of the drying liquid. In the fourth embodiment, even when changing from the drying liquid supply process to the drying process, the nozzle 4 sprays a heat medium having a temperature equal to or higher than the boiling point bp onto the second main surface Wb of the substrate W. Therefore, at the start point of the drying process (i.e., time point t2), the substrate temperature of the second main surface Wb of the substrate W can be made closer to the boiling point bp of the drying liquid. Therefore, the temperature of the drying liquid at the start point of the drying process can be made higher. That is, the surface tension of the drying liquid can be rapidly reduced, and the evaporation rate of the drying liquid can be rapidly increased. During the evaporation time in the drying process, the substrate temperature of at least a part (e.g., the central portion) of the first main surface Wa of the substrate W can be equal to or higher than the boiling point bp of the drying liquid. In the example of FIG. 11, the substrate temperature (maximum value) during the evaporation time is greater than the boiling point bp. That is, the temperature and flow rate of the heat medium are set such that the substrate temperature (maximum value) is equal to or higher than the boiling point bp. Thereby, the surface tension of the drying liquid can be further reduced, and the evaporation rate of the drying liquid can be further increased. Since the substrate temperature decreases toward the peripheral side, at least the temperature of the peripheral portion of the main surface of the substrate W does not reach the boiling point bp of the drying liquid. The drying liquid mainly flows outward on the first main surface Wa of the substrate W. That is, the drying liquid mainly does not flow in a state of floating from the first main surface Wa of the substrate W, but flows in a state of being in contact with the first main surface Wa of the substrate W. In addition, in the first to third embodiments, the substrate temperature of at least a part (e.g., the central portion) of the first main surface Wa of the substrate W during the evaporation time can also be equal to or higher than the boiling point bp of the drying liquid. That is, in the first to third embodiments, the temperature and flow rate of the heat medium can also be set such that the substrate temperature (maximum value) during the evaporation time is equal to or higher than the boiling point bp. <Fifth Embodiment> In the above example, the processing unit 1 sequentially performs a chemical solution process (step S3), a cleaning process (step S4), a drying solution supply process (step S5), and a drying process (step S6). However, it is not limited thereto. FIG. 12 is a flowchart showing a first example of the operation of the processing unit 1 according to the fifth embodiment. In the example of FIG. 12, the control unit 90 causes the processing unit 1 to execute the processes of steps S11 to S19 according to a preset processing order (process recipe). Steps S11 to S15 are the same as steps S1 to S5, respectively. However, in step S15 (drying solution supply process), the substrate heating unit 40 may not heat the substrate W. Next, the processing unit 1 hydrophobizes the first main surface Wa of the substrate W (step S16: hydrophobization process: equivalent to the liquid supply process). Specifically, the processing unit 1 includes a nozzle that ejects a hydrophobizing liquid, and ejects the hydrophobizing liquid from the nozzle onto the first main surface Wa of the rotating substrate W. The hydrophobizing liquid includes, for example, a silicon-based hydrophobizing liquid. The silicon-based hydrophobizing liquid is a hydrophobizing liquid that hydrophobizes silicon (Si) itself and compounds containing silicon. The hydrophobizing liquid is, for example, a silanizing liquid containing a liquid silanizing agent (also called a silane coupling agent). When the processing unit 1 sufficiently hydrophobizes the first main surface Wa of the substrate W, it stops ejecting the hydrophobizing liquid from the nozzle. Next, the processing unit 1 executes steps S17 to S19 from step S17. Steps S17 to S19 are the same as steps S5 to S7, respectively. As described above, in the above first example, the drying process (step S18) is also performed in the same manner as the drying process (step S6) in the first to fourth embodiments. Therefore, the collapse rate of the pattern on the substrate W can be reduced. Moreover, since the first main surface Wa of the substrate W has been hydrophobized, the contact angle of the first main surface Wa can be reduced. Therefore, the surface tension acting on the pattern can be reduced, and the collapse rate of the pattern can be further reduced. FIG. 13 is a flowchart showing a second example of the operation of the processing unit 1 of the fifth embodiment. In the example of FIG. 13, the control unit 90 causes the processing unit 1 to execute the processes of steps S21 to S26 in accordance with a preset processing sequence (process recipe). Steps S21 to S26 are the same as steps S1 to S3 and steps S5 to S7, respectively. However, at the end point of step S23 (chemical solution process: equivalent to the liquid supply process), the metal is exposed on the first main surface Wa of the substrate W. According to the second example, after step S23, step S24 (dry liquid supply process) is performed. Therefore, water is not supplied to the first main surface Wa of the substrate W. Therefore, the reaction between the metal and water can be avoided, and the defects caused by this reaction can be avoided. Also, in the above second example, the drying process (step S25) is also performed in the same manner as the drying process (step S6) in the first to fourth embodiments. Therefore, the collapse rate of the pattern on the substrate W can be reduced. <Sixth Embodiment> An example of the configuration of the substrate processing apparatus 100 of the sixth embodiment is the same as that of the substrate processing apparatus 100 of the first to fifth embodiments. However, a specific example of the shutter 6 is different from the shutter 6 of the first to fifth embodiments. FIG. 14 is a diagram schematically showing a first example of the configuration of the shutter 6 of the sixth embodiment. Hereinafter, the lower surface of the shutter 6 will be referred to as the lower surface 6a. A lower port (i.e., a gas ejection port) of the gas flow path 3g is formed at the center of the lower surface 6a of the shutter 6. As shown in FIG. 14, the gas flow path 3g has a vertical flow path 3ga and a diameter-expanded flow path 3gb. The vertical flow path 3ga is located vertically above the diameter-expanded flow path 3gb and extends in the vertical direction. In the example of FIG. 14, the outer peripheral surface of the vertical flow path 3ga is formed on the inner peripheral surface of the hollow shaft 61. That is, the vertical flow path 3ga is located inside the hollow shaft 61. In the example of FIG. 14, the lower port (i.e., the ejection port) of the nozzle 3i is located above the lower end of the vertical flow path 3ga. Above the lower port of the nozzle 3i, the vertical flow path 3ga corresponds to the cylindrical space between the inner peripheral surface of the hollow shaft 61 and the outer peripheral surface of the nozzle 3i. Below the lower port of the nozzle 3i, the vertical flow path 3ga corresponds to the columnar space surrounded by the inner peripheral surface of the hollow shaft 61. The lower end of the vertical flow path 3ga is connected to the upper end of the diameter-expanded flow path 3gb. The plan view size of the lower port (i.e., the lower port of the gas flow path 3g) of the diameter-expanded flow path 3gb is larger than the plan view size of the vertical flow path 3ga. Here, as an example, the inner peripheral surface of the hollow shaft 61 has a shape following the cylindrical side surface, and the lower port of the diameter-expanded flow path 3gb has a circular shape. In this case, the diameter (outer diameter) R2 of the vertical flow path 3ga is smaller than the diameter R1 of the lower port of the diameter-expanded flow path 3gb. In the example of FIG. 14, the diameter of the diameter-expanded flow path 3gb expands as it approaches the gas ejection port. The diameter-expanded flow path 3gb is formed by the inner peripheral surface of the blocking plate 6, and this inner peripheral surface is an inclined surface. The inner peripheral surface of the blocking plate 6 has a shape that follows, for example, the side surface of a truncated cone, and its lower end edge is connected to the lower surface 6a of the blocking plate 6. The lower end edge forms the lower port of the diameter-expanded flow path 3gb (i.e., the gas ejection port). Further, as shown in FIG. 14, the diameter of the diameter-expanded flow path 3gb may also monotonically increase as it approaches the lower surface 6a of the blocking plate 6. Alternatively, the diameter of the diameter-expanded flow path 3gb may also increase stepwise (i.e., in a stepped manner) as it approaches the lower surface 6a of the blocking plate 6. According to the sixth embodiment, the inert gas is also ejected from the lower port of the gas flow path 3g toward the first main surface Wa of the substrate W. FIG. 15 is a diagram schematically showing an example of the state of ejecting the inert gas. When the inert gas is ejected toward the first main surface Wa of the substrate W, the inert gas collides with the liquid film of the drying liquid on the first main surface Wa of the substrate W. Due to this collision, there is a risk of liquid splashing of the drying liquid. In the sixth embodiment, since the lower port of the gas flow path 3g is large, it is difficult for the drying liquid of the liquid splashing to reach the lower surface 6a of the blocking plate 6. A specific example of the operation of the processing unit 1 in the sixth embodiment may be the same as or different from the operation of the processing unit 1 in the first to fifth embodiments. As an example, the processing unit 1 in the sixth embodiment operates according to the flowchart of FIG. 4. FIG. 16 is a diagram showing a first example of the timing chart of the processing unit 1 in the sixth embodiment. In the example of FIG. 16, an example of the time change of the position of the blocking plate 6 and the time change of the flow rate of the inert gas are shown. In the example of FIG. 16, similar to the first to fifth embodiments, the movement drive unit 35i moves the blocking plate 6 from the blocking processing position P1 to the drying position P2 (time point t2) when the supply of the drying liquid is stopped. In the sixth embodiment, the gas flow path 3g of the blocking plate 6 has a diameter-expanded flow path 3gb. Therefore, as described above, even if the blocking plate 6 is further moved to a position closer to the first main surface Wa of the substrate W, it is possible to suppress the attachment of the drying liquid to the blocking plate 6. For example, the drying position can be set at a position where the distance between the lower surface 6a of the blocking plate 6 and the first main surface Wa of the substrate W is 2 mm or less, or can also be set at a position where it is 1 mm or less. Moreover, by narrowing this distance, the processing unit 1 can dry the substrate W more quickly. That is, since this distance can be set to be narrow from the initial stage of the drying process, the processing unit 1 can dry the substrate W with higher drying performance from the initial stage of the drying process. In particular, the drying performance in the initial stage of the drying process has a strong influence on suppressing the collapse of the pattern. Therefore, the processing unit 1 can further reduce the pattern collapse rate. As shown in FIG. 16, the processing unit 1 can also supply an inert gas to the first main surface Wa of the substrate W in the drying liquid supply step (step S5). That is, the control unit 90 can also open the supply valve 32g in the drying liquid supply step. Thereby, in the drying liquid supply step, an inert gas is also ejected from the lower port of the gas flow path 3g. Thereby, it is possible to suppress the volatile components of the drying liquid from remaining in the space between the shutter 6 and the substrate W. The flow rate of the inert gas in the drying liquid supply step is set to, for example, 20 mL (milliliters) / min or less. In the example of FIG. 16, when the processing unit 1 moves the shutter 6 to the drying position P2 in the drying step, the flow rate of the inert gas is increased. For example, the flow rate adjustment valve 33g can increase the flow rate of the inert gas from a value of 20 mL (milliliters) / min or less to a value of 30 mL / min or more. In the example of FIG. 16, the flow rate adjustment valve 33g increases the flow rate of the inert gas stepwise over time. The flow rate adjustment valve 33g can increase the flow rate to 100 mL / min or more as the final flow rate of the inert gas in the drying step. The processing unit 1 can increase the flow rate to 150 mL / min or more, or can also increase it to 200 mL / min or more. As described above, the processing unit 1 lowers the shutter 6 to the drying position P2 and increases the flow rate of the inert gas. Therefore, the processing unit 1 can dry the substrate W with high drying performance from the initial stage of the drying step. And, in the sixth embodiment, since the gas flow path 3g has the enlarged diameter flow path 3gb, even if the flow rate of the inert gas is increased and liquid splashing is likely to occur, the liquid splashing is still not likely to reach the shutter 6. Therefore, it is also possible to suppress the drying liquid from adhering to the shutter 6. In addition, the flow rate adjustment valve 33g may increase the flow rate of the inert gas not stepwise but in steps. That is, the flow rate adjustment valve 33g can also raise the flow rate of the inert gas to the final value at the time point t2. In this way, even if an inert gas is supplied at a large flow rate from the initial stage of the drying step, since the gas flow path 3g has the enlarged diameter flow path 3gb, the liquid splashing is still not likely to reach the shutter 6. And, if the processing unit 1 supplies an inert gas at a large flow rate from the initial stage of the drying step, the drying performance can be further improved. Therefore, the processing unit 1 can further reduce the collapse rate of the pattern. FIG. 17 is a diagram showing a second example of a timing chart of the processing unit 1 according to the sixth embodiment. In the example of FIG. 17, at time point t11 in the middle of the drying liquid supply process, the control unit 90 causes the moving drive unit 35i to lower the shutter 6. Specifically, in the example of FIG. 17, the shutter 6 is located at the first shutter processing position P11 at the initial stage of the drying liquid supply process. Then, the moving drive unit 35i moves the shutter 6 from the first shutter processing position P11 to the second shutter processing position P12 at time point t11. The second shutter processing position P12 is a position closer to the first main surface Wa of the substrate W than the first shutter processing position P11 and farther from the first main surface Wa of the substrate W than the drying position P2 (the first drying position P21 in the figure). That is, the second shutter processing position P12 is a position between the first shutter processing position P11 and the drying position P2. Each of the first shutter processing position P11 and the second shutter processing position P12 is an example of the shutter processing position P1. The second shutter processing position P12 can be set, for example, at a position where the distance between the shutter 6 and the substrate W is 10 mm or less, or can be set at a position of about 5 mm. The first shutter processing position P11 can be set, for example, at a position where the distance between the shutter 6 and the substrate W is 20 mm or more (for example, about 30 mm). As described above, in the example of FIG. 17, in the drying liquid supply process, the processing unit 1 supplies the drying liquid to the first main surface Wa of the substrate W in a state where the shutter 6 is located at the first shutter processing position P11, and then supplies the drying liquid and moves the shutter 6 to the second shutter processing position P12. Here, the case where the gas flow path 3g extends in a cylindrical shape will be described. FIG. 18 is a diagram showing an example of the state of the processing unit 1 in the drying liquid supply process. Here, the shutter 6 is located at the second shutter processing position P12. In the example of FIG. 18, the outlet portion below the ejection port of the nozzle 3i in the gas flow path 3g extends in the vertical direction with the same width. The inert gas flows through the space between the liquid column-shaped drying liquid from the ejection port of the nozzle 3i and the inner peripheral surface of the shutter 6 in the outlet portion, and then flows through the space between the lower surface 6a of the shutter 6 and the first main surface Wa of the substrate W. Since the outlet portion of the gas flow path 3g extends in the vertical direction with the same width, the volume of this space is relatively small. Also, when the shutter 6 is located at the second shutter processing position P12, the volume of the space between the shutter 6 and the substrate W is also relatively small. Therefore, the cross-sectional area of the flow path of the inert gas is small. Therefore, the pressure of the inert gas becomes high, and the liquid column-shaped drying liquid is likely to be affected by the air flow of the inert gas. As a result, there is a risk of causing the liquid column-shaped drying liquid to shake. In FIG. 18, the shaking of the liquid column-shaped drying liquid is schematically shown by a wavy line. Due to this kind of shaking of the drying liquid, there is a risk that the liquid attachment position on the first main surface Wa of the substrate W shakes, or droplets fly off from the liquid column-shaped drying liquid and adhere to the shutter 6. FIG. 19 is a diagram showing an example of the state of the processing unit 1 in the drying liquid supply process of the sixth embodiment. In the example of FIG. 19, the gas flow path 3g has a diameter-expanded flow path 3gb. Therefore, the volume of the space between the liquid column-shaped drying liquid from the nozzle 3i and the inner peripheral surface of the shielding plate 6 is relatively large. Therefore, the inert gas can flow at a position relatively far from the liquid column-shaped drying liquid, and the influence of the flow of the inert gas on the drying liquid can be reduced. Therefore, the shaking of the liquid column-shaped drying liquid can be reduced. In the above example, during the final period of the drying liquid supply process (step S5), the shielding plate 6 is located at the second shielding processing position P12 closer to the drying position P2. Therefore, in the next drying process (step S6), the moving distance of the shielding plate 6 can be shortened. That is, at the initial stage of the drying process, the shielding plate 6 only needs to move from the second shielding processing position P12 to the drying position P2, and can reach the drying position P2 with a shorter moving distance compared to the moving distance from the first shielding processing position P11 to the drying position P2. Therefore, the moving drive unit 35i can make the shielding plate 6 reach the drying position P2 at an earlier timing. Therefore, the drying performance at the initial stage of the drying process can be further improved. In addition, the time point t11 when the shielding plate 6 starts to move toward the second shielding processing position P12 can also be, for example, after the central time point in the drying liquid supply time for supplying the drying liquid. That is, the time difference between the time point t11 and the time point t2 can be shorter than the time difference between the time point t1 and the time point t11. In the example of FIG. 17, at the time point t21 in the middle of the drying process, the control unit 90 commands the moving drive unit 35i to move the shielding plate 6 from the first drying position P21 to the second drying position P22. The second drying position P22 is a position closer to the first main surface Wa of the substrate W than the first drying position P21. The second drying position P22 can be a position with a distance of 0.5 mm or less from the first main surface Wa of the substrate W. Each of the first drying position P21 and the second drying position P22 is an example of the drying position P2. The time point t21 when the shielding plate 6 starts to move toward the second drying position P22 can also be, for example, after the time point when the scattering of the drying liquid from the periphery of the substrate W substantially ends. That is, after the drying liquid above the pattern of the substrate W is substantially thrown to the outside, the shielding plate 6 descends to the second drying position P22. Thereby, in the state where the shielding plate 6 is located at the second drying position P22, the drying liquid in the pattern of the substrate W can be evaporated, and the substrate W can be dried more rapidly. The control unit 90 can also command the moving drive unit 35i to move the shielding plate 6 to the second drying position P22 when a preset time has elapsed from the time point t2. This time is set to a time sufficient for the scattering of the drying liquid from the substrate W to substantially end. FIG. 20 is a diagram showing a second example of the configuration of the shutter 6 in the sixth embodiment. In the second example, a gas nozzle 3gA is provided. Similar to the nozzle 3i, the gas nozzle 3gA is provided inside the hollow shaft 61. The gas nozzles 3gA are adjacent to each other in the horizontal direction. The gas nozzle 3gA extends in the vertical direction, and its lower port functions as a gas ejection port. The upstream end of the gas nozzle 3gA is connected to the downstream end of the supply pipe 31gA. The upstream end of the supply pipe 31gA is connected to a gas supply source. A supply valve 32gA, a flow rate adjustment valve 33gA, and a heater 34gA are provided in the supply pipe 31gA. The supply valve 32gA switches the opening and closing of the supply pipe 31gA. The flow rate adjustment valve 33gA adjusts the flow rate of the inert gas flowing through the supply pipe 31gA. The heater 34gA heats the inert gas flowing through the supply pipe 31gA. The heater 34gA may be, for example, a resistance heater having a heating wire. The supply valve 32gA, the flow rate adjustment valve 33gA, and the heater 34gA are controlled by the control unit 90. In the drying liquid supply step (step S5), the control unit 90 can open the supply valve 32g and close the supply valve 32gA. Thereby, in the drying liquid supply step, inert gas is not ejected from the gas nozzle 3gA, but inert gas is ejected from the gas flow path 3g. Since inert gas is not ejected from the gas nozzle 3gA provided at a position close to the nozzle 3i, the shaking of the liquid column-like drying liquid caused by the inert gas can be suppressed. On the other hand, in the drying step (step S6), the control unit 90 opens the supply valve 32g and the supply valve 32gA. Thereby, in the drying step, inert gas is ejected from the gas flow path 3g and the gas nozzle 3gA. Therefore, inert gas can be more appropriately supplied to the central portion of the substrate W. The above-mentioned flow rate value of the inert gas can be the sum of the flow rates of the inert gas flowing through the gas flow path 3g and the gas nozzle 3gA. As described above, although the substrate processing apparatus 100 and the substrate processing method have been described in detail, the above description is illustrative in all aspects, and the present disclosure is not limited thereto. Also, the above various modification examples can be combined and applied as long as they do not contradict each other. Moreover, it should be understood that various modification examples not illustrated can be conceived without departing from the scope of the present disclosure. In the above example, although dedicated nozzles are provided for each fluid, one nozzle can also be shared by fluids of different types. Also, in the above example, the substrate heating unit 40 supplies the heat medium to the second main surface Wb of the substrate W, but it is not limited thereto. The substrate heating unit 40 may also include, for example, a heater provided at a position facing the second main surface Wb of the substrate W in the vertical direction. The heater may be, for example, a resistance heater including a heating wire, or an optical heater that outputs light for heating. Further, in the above example, the substrate heating unit 40 heats the second main surface Wb of the substrate W during the evaporation time from the time point t2 when the supply of the drying liquid is stopped to the time point t3. However, the substrate heating unit 40 may also interrupt the heating during a part of the interruption time within the evaporation time. 1: Processing unit 2: Substrate holding unit 3, 3c, 3i, 3w, 4: Nozzle 3g: Gas flow path 3gA: Gas nozzle 3ga: Vertical flow path 3gb: Diameter-expanded flow path 6: Shut-off plate 6a: Lower surface 7: Protection member 10: Chamber 11: Fan filter unit 12: Drain pipe 13: Exhaust pipe 21: Rotary base 22: Chuck pin 23: Rotary drive unit 31, 31c, 31g, 31gA, 31i, 31w, 41: Supply pipe 32, 32c, 32g, 32gA, 32i, 32w, 42: Supply valve 33, 33c, 33g, 33gA, 33i, 33w, 43, 452, 453: Flow rate adjustment valve 34g, 34gA, 44: Heater 35, 35c, 35i, 35w: Moving drive unit 40: Substrate heating unit 45: Mixing unit 61: Hollow shaft 71: Protection member lifting drive unit 72: Cup 90: Control unit 91: Data processing unit 92: Memory unit 100: Substrate processing apparatus 110: Loading block 111: Loading port 112: First transfer unit 120: Processing block 122: Second transfer unit 123: Placement unit 231: Shaft 232: Motor 351: Arm 352: Support column 353: Drive source 411: Common pipe 412: First temperature pipe 413: Second temperature pipe 451: Multiport valve 921: Non-transitory memory unit 922: Transitory memory unit bp: Boiling point C: Carrier G1, G2: Curve P1: Shut-off processing position P2: Drying position P11: First shut-off processing position P12: Second shut-off processing position P21: First drying position P22: Second drying position Q1: Axis of rotation Q2: Central axis R1, R2: Diameter S1~S7: Step S11~S19: Step S21~S26: Step T: Drying liquid supply time T1: Pre-time T2: Post-time TW: Tower t1~t3, t11, t12, t21: Time point W: Substrate Wa: First main surface Wb: Second main surface FIG. 1 is a plan view schematically showing an example of the configuration of a substrate processing apparatus. FIG. 2 is a block diagram schematically showing an example of the internal configuration of a control unit. FIG. 3 is a longitudinal sectional view schematically showing an example of the configuration of a processing unit according to the first embodiment. FIG. 4 is a flowchart showing an example of the operation of the processing unit. FIGS. 5(a) to 5(b) are diagrams schematically showing an example of the state of the processing unit in each step. FIGS. 6(a) to 6(b) are diagrams schematically showing an example of the state of the processing unit in each step. FIG. 7 is a diagram schematically showing an example of a timing chart of the processing unit and the time change of the temperature of the first main surface of the substrate. FIG. 8 is a diagram schematically showing an example of the configuration of a substrate heating unit according to the second embodiment. FIG. 9 is a diagram schematically showing an example of a timing chart of the processing unit, the flow rate of the heat medium, and the time change of the temperature of the heat medium according to the second embodiment. FIG. 10 is a diagram schematically showing an example of a timing chart of the processing unit and the temperature change of the first main surface of the substrate according to the third embodiment. FIG. 11 is a diagram schematically showing an example of a timing chart of the processing unit, the flow rate of the heat medium, the temperature of the heat medium, and the time change of the temperature of the first main surface of the substrate according to the fourth embodiment. FIG. 12 is a flowchart showing a first example of the operation of the processing unit according to the fifth embodiment. FIG. 13 is a flowchart showing a second example of the operation of the processing unit according to the fifth embodiment. FIG. 14 is a diagram schematically showing a first example of the configuration of a shutter according to the sixth embodiment. FIG. 15 is a diagram schematically showing an example of the state of ejecting an inert gas. FIG. 16 is a diagram showing a first example of the timing chart of the processing unit according to the sixth embodiment. FIG. 17 is a diagram schematically showing a second example of the timing chart of the processing unit according to the sixth embodiment. FIG. 18 is a diagram showing an example of the state of the processing unit in a drying liquid supply process. FIG. 19 is a diagram showing an example of the state of the processing unit in the drying liquid supply process according to the sixth embodiment. FIG. 20 is a diagram showing a second example of the configuration of a shutter according to the sixth embodiment. S1~S7: Steps

Claims

1. A substrate processing method, comprising: a holding step, which holds a substrate having a first main surface with a pattern formed thereon and a second main surface opposite to the first main surface; a liquid supply step, which supplies a processing liquid to the first main surface of the substrate; a drying liquid supply step, which supplies a drying liquid to the first main surface of the substrate after the liquid supply step; and a drying step, which heats the second main surface of the substrate for a predetermined period after the drying liquid supply step, sets the substrate temperature of the first main surface of the substrate to be above the substrate temperature in the drying liquid supply step, thereby drying the substrate; and sets the substrate temperature of at least a portion of the first main surface of the substrate to be above the boiling point of the drying liquid during the predetermined period.

2. A substrate processing method, comprising: a holding step, which holds a substrate having a first main surface with a pattern formed thereon and a second main surface opposite to the first main surface; a liquid supply step, which supplies a processing liquid to the first main surface of the substrate; a drying liquid supply step, which supplies a drying liquid to the first main surface of the substrate after the liquid supply step; and a drying step, which heats the second main surface of the substrate for a predetermined period after the drying liquid supply step, sets the substrate temperature of the first main surface of the substrate to be above the substrate temperature in the drying liquid supply step, and dries the substrate; and in the drying liquid supply step, heats the second main surface of the substrate with a first heat per unit time; and in the predetermined period of the drying step, heats the second main surface of the substrate with a second heat per unit time greater than the first heat.

3. The substrate processing method of claim 1 or 2, wherein a heat medium is supplied to the second main surface of the substrate during the specified period.

4. The substrate processing method of claim 2, wherein in the above-mentioned drying liquid supply step, a heat medium is supplied to the second main surface of the substrate, and the heat medium is obtained by mixing a high-temperature heat medium with a low-temperature heat medium with a temperature lower than that of the high-temperature heat medium; the mixing ratio of the high-temperature heat medium and the low-temperature heat medium is adjusted, and the heat medium with a temperature higher than that of the heat medium in the above-mentioned drying liquid supply step is supplied to the second main surface of the substrate for at least the above-mentioned predetermined period in the above-mentioned drying step.

5. The substrate processing method of claim 3, wherein during the specified period, the heat medium at a temperature above the boiling point of the drying liquid is supplied to the second main surface of the substrate.

6. The substrate processing method of claim 3, wherein in the above-mentioned drying liquid supply process, the heat medium at a temperature above the boiling point of the drying liquid is supplied to the second main surface of the substrate, and the drying liquid is supplied at a flow rate at which the substrate temperature of the first main surface of the substrate does not reach the boiling point.

7. The substrate processing method of claim 3, wherein the heat medium comprises a liquid; in the drying liquid supply process, the drying liquid is supplied to the first main surface of the substrate while the blocking plate having a facing surface facing the first main surface of the substrate is in a blocking processing position; during the specified period of the drying process, while the blocking plate is moved to a drying position closer to the first main surface than the blocking processing position, an inert gas is supplied to the first main surface of the substrate from a gas outlet at the center of the blocking plate.

8. The substrate processing method of claim 7, wherein, during the specified period, the heated inert gas is supplied to the first main surface of the substrate.

9. The substrate processing method of claim 7, wherein in the drying liquid supply process, the inert gas is supplied to the first main surface of the substrate through a gas flow path inside the blocking plate having an expanded flow path that widens as it moves toward the gas outlet; the blocking plate is moved from the blocking processing position to the drying position, and the flow rate of the inert gas is increased.

10. The substrate processing method of claim 9, wherein in the above-mentioned drying liquid supply process, while the blocking plate is located in one of the above-mentioned blocking processing positions, namely the first blocking processing position, the drying liquid is supplied to the first main surface of the substrate, and then the drying liquid is supplied, and the blocking plate is moved to one of the above-mentioned blocking processing positions, and moves to a second blocking processing position closer to the first main surface of the substrate than the first blocking processing position.

11. The substrate processing method of claim 1 or 2, wherein during the specified period of the drying process, the substrate is rotated at a higher rotational speed than the rotational speed of the substrate in the drying liquid supply process.

12. The substrate processing method of claim 1 or 2, wherein in the above-mentioned drying liquid supply process, the second main surface of the substrate is heated only during a period after the drying liquid supply time for supplying the above-mentioned drying liquid.

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