Substrate processing method

Abstract

Provided is a technology that can effectively reduce a substrate pattern collapse rate. This substrate processing method comprises a retention step, a liquid supply step, a drying liquid supply step, and a drying step. In the retention step, a substrate having a first main surface on which a pattern has been formed and a second main surface on the opposite side from the first main surface is retained. In the liquid supply step, a processing liquid is supplied to the first main surface of the substrate. In the drying liquid supply step, a drying liquid is supplied to the first main surface of the substrate after the liquid supply step, at such a flow rate that the temperature of the first surface of the substrate is less than the boiling point (bp) of the drying liquid, while at least one section of the second main surface of the substrate is heated to the boiling point (bp) of the drying liquid or higher. In the drying step, the substrate is dried after the drying liquid supply step.

Description

Substrate processing method

[0001] The present disclosure relates to a substrate processing method.

[0002] Single-wafer substrate processing apparatuses for processing substrates have been disclosed in the past (for example, Patent Document 1). In Patent Document 1, the substrate processing apparatus supplies a rinse liquid to the substrate, then supplies isopropyl alcohol, which has a lower surface tension than the rinse liquid, to the substrate, and then dries the substrate. This prevents the pattern on the substrate from collapsing during drying.

[0003] JP 2015-23182 A

[0004] However, Patent Document 1 does not consider the temperature of isopropyl alcohol, and therefore is unable to effectively reduce the rate of pattern collapse.

[0005] Therefore, an object of the present disclosure is to provide a technique that can effectively reduce the rate of pattern collapse on a substrate.

[0006] A first aspect is a substrate processing method comprising: a holding step of holding a substrate having a first main surface on which a pattern is formed 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, after the liquid supply step, heating at least a portion of the second main surface of the substrate to a temperature equal to or higher than the boiling point of a drying liquid, while supplying the drying liquid to the first main surface of the substrate at a flow rate such that the temperature of the first main surface of the substrate is below the boiling point of the drying liquid; and a drying step of drying the substrate after the drying liquid supply step.

[0007] A second aspect is the substrate processing method according to the first aspect, wherein in the drying liquid supplying step, a heat medium having a boiling point equal to or higher than the boiling point of the drying liquid is supplied to the second main surface of the substrate.

[0008] A third aspect is the substrate processing method according to the first or second aspect, wherein in the drying liquid supplying step, a peripheral portion of the second main surface of the substrate is heated to a boiling point of the drying liquid or higher.

[0009] A fourth aspect is a substrate processing method according to the third aspect, wherein in the drying liquid supply step, a central portion of the second main surface of the substrate is heated to a temperature lower than a temperature of the peripheral portion of the second main surface.

[0010] A fifth aspect is a substrate processing method according to the fourth aspect, wherein in the drying liquid supply step, a heat medium at a first medium temperature is supplied to the peripheral portion of the second main surface of the substrate, and a heat medium at a second medium temperature lower than the first medium temperature is supplied to the central portion of the second main surface of the substrate.

[0011] A sixth aspect is a substrate processing method according to any one of the first to fifth aspects, wherein, in the drying liquid supply step, the second main surface of the substrate is heated only during a latter part of a drying liquid supply time during which the drying liquid is supplied.

[0012] A seventh aspect is a substrate processing method according to any one of the first to sixth aspects, wherein in the drying liquid supplying step, the temperature of the first main surface of the substrate is equal to or higher than 60 degrees Celsius and lower than the boiling point of the drying liquid.

[0013] According to the first aspect, in the drying liquid supplying step, while at least a portion of the second main surface of the substrate is heated to a temperature equal to or higher than the boiling point of the drying liquid, the drying liquid is supplied at a flow rate such that the temperature of the first main surface of the substrate is below the boiling point. Therefore, while the temperature of the first main surface of the substrate is brought closer to the boiling point of the drying liquid, boiling of the drying liquid can be more reliably suppressed, thereby suppressing particle adhesion. Furthermore, since the temperature of the first main surface is closer to the boiling point, in the subsequent drying step, the drying liquid can be evaporated in a shorter time with a lower surface tension. Therefore, the pattern collapse rate can be effectively reduced.

[0014] According to the second aspect, the temperature of at least a part of the second main surface of the substrate can be made equal to or higher than the boiling point of the drying liquid with a simple configuration.

[0015] According to the third aspect, the pattern collapse rate can be reduced in the peripheral portion, which tends to be higher than the pattern collapse rate in the central portion, and therefore the pattern collapse rate can be reduced over the entire first main surface of the substrate.

[0016] According to the fourth aspect, the collapse rate of the pattern in the central portion of the first main surface of the substrate can be reduced while reducing power consumption, thereby further reducing the collapse rate of the entire pattern.

[0017] According to the fifth aspect, the collapse rate of the pattern over the entire first main surface of the substrate can be effectively reduced with a simple configuration.

[0018] According to the sixth aspect, it is possible to reduce power consumption.

[0019] According to the seventh aspect, the rate of pattern collapse can be effectively reduced.

[0020] 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 a first embodiment. FIG. 4 is a flowchart showing an example of the operation of a processing unit. FIG. 5 is a diagram schematically showing an example of the state of a processing unit in a drying liquid supplying step. FIG. 6 is a timing chart of a processing unit, and a diagram schematically showing an example of a change in medium temperature of a heat medium over time and a change in temperature of a first main surface of a substrate over time. FIG. 7 is a diagram schematically showing a first example of a substrate heating section according to a second embodiment. FIG. 8 is a diagram schematically showing a first example of a partial configuration of a processing unit according to the second embodiment. FIG. 9 is a diagram schematically showing a second example of a partial configuration of a processing unit according to the second embodiment. FIG. 10 is a diagram schematically showing an example of a timing chart of a processing unit according to a third embodiment. FIG. 11 is a flowchart showing a first example of the operation of a processing unit according to a fourth embodiment. FIG. 12 is a flowchart showing a second example of the operation of a processing unit according to the fourth embodiment. FIG. 13 is a diagram schematically showing an example of a configuration of a processing unit according to a fifth embodiment.

[0021] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the drawings, the dimensions and numbers of each part are exaggerated or simplified as necessary for ease of understanding. Parts having similar configurations and functions are assigned the same reference numerals, and duplicate explanations will be omitted below.

[0022] In the following description, the same components are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed descriptions of them may be omitted to avoid duplication.

[0023] Furthermore, in the following description, even if ordinal numbers such as "first" or "second" are used, these terms are used for convenience to facilitate understanding of the contents of the embodiments, and are not limited to the order that may result from these ordinal numbers.

[0024] When expressions indicating relative or absolute positional relationships (e.g., "in one direction," "along one direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.) are used, unless otherwise specified, the expressions not only strictly represent the positional relationship but also represent a state in which there is a relative displacement in terms of angle or distance within a range in which tolerance or equivalent functionality is obtained. When expressions indicating an equal state (e.g., "identical," "equal," "homogeneous," etc.) are used, the expressions not only represent a state in which there is strict quantitative equality but also represent a state in which there is a difference in which tolerance or equivalent functionality is obtained, unless otherwise specified. When expressions indicating a shape (e.g., "rectangular shape" or "cylindrical shape," etc.) are used, the expressions not only represent a geometrically strict shape but also represent a shape with, for example, irregularities or chamfers within a range in which equivalent effects are obtained. When the expressions "comprise," "include," "have," "includes," "includes," or "have" are used to describe one component, the expressions are not exclusive expressions that exclude the presence of other components. When the phrase "at least one of A, B, and C" is used, the phrase includes A only, B only, C only, any two of A, B, and C, and all of A, B, and C.

[0025] 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.

[0026] The substrate W may be, for example, a semiconductor wafer, a liquid crystal display substrate, an organic electroluminescence (EL) (electroluminescence) substrate, an FPD (flat panel display) substrate, an optical display substrate, a magnetic disk substrate, an optical disk substrate, a magneto-optical disk substrate, a photomask substrate, or a solar cell substrate. The substrate W has a thin, flat plate shape with a first main surface Wa and a second main surface Wb. The second main surface Wb is the surface 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 circular plate shape. The diameter of the substrate W is, for example, approximately 300 mm, and the thickness of the substrate W is, for example, approximately 0.5 mm or more and approximately 3 mm or less. A pattern is formed on the main surface of the substrate W. The pattern here includes, for example, at least one of a wiring pattern, an electrode pattern, a semiconductor pattern, and an insulating pattern. The aspect ratio of 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 high aspect ratio patterns are prone to collapse.

[0027] 1, the substrate processing apparatus 100 includes an indexer block 110, a processing block 120, and a control unit 90. The processing block 120 is a section that mainly processes substrates W, and the indexer block 110 is a section that mainly transports substrates W between the outside of the substrate processing apparatus 100 and the processing block 120.

[0028] The indexer block 110 includes a load port 111 and a first transport part 112. A substrate container (hereinafter referred to as a carrier) C that has been carried in from outside is placed on the load port 111. The carrier C accommodates a plurality of substrates W, for example, arranged at intervals in the vertical direction. In the example of Fig. 1, a plurality of load ports 111 are arranged.

[0029] The first transport unit 112 is a transport robot and can remove unprocessed substrates W from the carriers C placed on each load port 111. The first transport unit 112 may also be called an indexer robot. The first transport unit 112 transports the unprocessed substrates W removed from the carriers C to the processing block 120. The processing block 120 can process the unprocessed substrates W. The first transport unit 112 can also receive processed substrates W from the processing block 120 and transport the processed substrates W to the carriers C of the load port 111.

[0030] In the example of FIG. 1 , the processing block 120 includes a plurality of processing units 1 and a second transport part 122. The second transport part 122 is a transport robot and can transport substrates W between the first transport part 112 and the plurality of processing units 1. In the example of FIG. 1 , the processing block 120 also includes a receiver 123. The receiver 123 is, for example, a shelf on which a plurality of substrates W can be placed in a vertically arranged state. The first transport part 112 places an unprocessed substrate W on the receiver 123. The second transport part 122 removes the unprocessed substrate W from the receiver 123 and transports 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 transport part 122 removes the processed substrate W from the processing unit 1 and transports the substrate W to the receiver 123. The first transport part 112 takes the substrate W from the platform 123 and transports the substrate W to a carrier C in the load port 111 .

[0031] 1 , a plurality of (e.g., four) processing units 1 are arranged to surround the second transport section 122 in a plan view. This second transport section 122 may also be called a center robot. At each position in a plan view, a plurality of processing units 1 may be stacked vertically. In other words, a plurality of (four in the figure) towers TW each made up of a plurality of processing units 1 stacked vertically may be arranged to surround the second transport section 122.

[0032] The control unit 90 performs overall control of the substrate processing apparatus 100. Specifically, the control unit 90 controls the first transport unit 112, the second transport unit 122, and the processing unit 1. FIG. 2 is a block diagram schematically illustrating an example of the internal configuration of the control unit 90. The control unit 90 is an electronic circuit and includes, for example, a data processing unit 91 and a storage unit 92. In the example illustrated in FIG. 2, the data processing unit 91 and the storage unit 92 are connected to each other via a bus 93. The data processing unit 91 may be, for example, an arithmetic processing device such as a central processing unit (CPU). The storage unit 92 may include a non-transitory storage unit (e.g., a read-only memory (ROM)) 921 and a temporary storage unit (e.g., a random access memory (RAM)) 922. The non-transitory storage unit 921 may store, for example, a program that defines the processing to be performed by the control unit 90. The data processing unit 91 executes this program, allowing the control unit 90 to perform the processing defined in the program. Of course, some or all of the processing performed by the control unit 90 may be performed by hardware such as a dedicated logic circuit.

[0033] <Overview of Processing Unit> Fig. 3 is a longitudinal cross-sectional view schematically showing an example of the configuration of a processing unit 1 according to the first embodiment. Note that all processing units 1 belonging to the substrate processing apparatus 100 do not need to have the configuration illustrated in Fig. 3. It is sufficient that at least one processing unit 1 of the substrate processing apparatus 100 has the configuration illustrated in Fig. 3.

[0034] The processing unit 1 includes a substrate holder 2 , a discharge unit 3 , and a substrate heater 4 .

[0035] 3, the processing unit 1 is also provided with a chamber 10. The chamber 10 has a box-like shape, and its internal space corresponds to a processing space for processing a substrate W. The chamber 10 is provided with an openable / closable loading / unloading port (not shown). The second transport part 122 loads an unprocessed substrate W into the chamber 10 through the loading / unloading port, and loads a processed substrate W out of the chamber 10 through the loading / unloading port.

[0036] In the example of Fig. 3, a fan filter unit 11 is provided on the ceiling of chamber 10. The fan filter unit 11 takes in air from outside chamber 10, cleans it, and then blows the cleaned air into chamber 10. Operation of fan filter unit 11 creates a downflow of clean air within chamber 10. In the example of Fig. 3, the upstream end of exhaust pipe 13 is connected to the lower part of the side wall of chamber 10. Gas within chamber 10 is exhausted to the outside through exhaust pipe 13.

[0037] The substrate holder 2 is provided in the chamber 10 and holds the substrate W in a horizontal position while rotating the substrate W around a rotation axis Q1. The horizontal position here means that the thickness direction of the substrate W is aligned with the vertical direction. The rotation axis Q1 is an axis that passes through the center of the substrate W and is aligned with the vertical direction. Such a substrate holder 2 may also be called a spin chuck.

[0038] In this example, 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 holder 2 corresponds to the upper surface. The pattern includes, for example, at least one of a wiring pattern, an insulating pattern, and a semiconductor pattern.

[0039] In the example of FIG. 3 , the substrate holder 2 includes a spin base 21, chuck pins 22, and a rotation driver 23. The spin base 21 has a plate-like shape (e.g., a disk shape) and is disposed with its thickness direction aligned vertically. A plurality of chuck pins 22 are provided on the upper surface of the spin base 21. The plurality of chuck pins 22 are disposed at equal intervals along the circumferential direction about the rotation axis Q1. The plurality of chuck pins 22 are disposed so as to be displaceable between a holding position and a release position, which will be described below. The holding position is a position where the chuck pins 22 abut against the periphery of the substrate W. The plurality of chuck pins 22 hold the substrate W by stopping at their respective holding positions. FIG. 3 shows the chuck pins 22 stopped at the holding position. The release position is a position where each chuck pin 22 is separated from the substrate W. The plurality of chuck pins 22 stop at their respective release positions, thereby releasing the substrate W from the holding of the substrate W by the plurality of chuck pins 22. The substrate holder 2 also includes a pin drive unit (not shown) that displaces the chuck pins 22. The pin drive unit includes a drive source such as a motor and an air cylinder, and is controlled by the control unit 90.

[0040] The rotation drive 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 spin base 21, and the shaft 231 extends from the lower surface of the spin base 21 along a rotation axis Q1. The motor 232 is controlled by the control unit 90 to rotate the shaft 231 about the rotation axis Q1. This causes the spin base 21, chuck pins 22, and substrate W to rotate integrally about the rotation axis Q1.

[0041] It should be noted that the substrate holder 2 does not necessarily have to have the chuck pins 22. For example, the substrate holder 2 may hold the substrate W by a chuck method such as a vacuum chuck, an electrostatic chuck, or a Bernoulli chuck.

[0042] The discharge unit 3 discharges the processing liquid toward the first main surface Wa of the substrate W held by the substrate holding unit 2. As shown in Fig. 3, the discharge unit 3 includes at least one nozzle 30. The nozzle 30 discharges the processing liquid toward the first main surface Wa of the substrate W held by the substrate holding unit 2. In this case, the first main surface Wa corresponds to the upper surface of the substrate W, and therefore the nozzle 30 is provided vertically above the substrate W held by the substrate holding unit 2. The nozzle 30 is, for example, a straight nozzle that discharges the processing liquid in the form of a continuous flow.

[0043] In the example of Fig. 3, nozzles 30c, 30w, and 30i are shown as nozzles 30. In the example of Fig. 3, nozzles 30c, 30w, and 30i extend vertically. In the example of Fig. 3, nozzle 30c has an outlet 3c formed in its lower surface, nozzle 30w has an outlet 3w formed in its lower surface, and nozzle 30i has an outlet 3i formed in its lower surface. Nozzle 30c ejects a chemical liquid from outlet 3c, nozzle 30w ejects a rinse liquid from outlet 3w, and nozzle 30i ejects a drying liquid from outlet 3i. The chemical liquid, rinse liquid, and drying liquid are all examples of processing liquids, and specific examples will be described later.

[0044] Nozzles 30c, 30w, and 30i eject the processing liquid toward the center of the first main surface Wa of the substrate W held by the substrate holding unit 2. In the example of FIG. 3, nozzles 30c, 30w, and 30i are adjacent to each other in the horizontal direction and fixed to each other. In the example of FIG. 3, nozzles 30c, 30w, and 30i are provided inside an opposing member 60. The opposing member 60 has, for example, a cylindrical shape. The opposing member 60 has a hollow shape, and the lower end opening of the hollow portion opens at the lower surface of the opposing member 60. Nozzles 30c, 30w, and 30i are provided inside the hollow portion of the opposing member 60, and the processing liquid ejected from each nozzle 30 flows out from the lower end opening of the opposing member 60. In the example of FIG. 3, the opposing member 60 is provided at a position vertically facing the center of the substrate W held by the substrate holding unit 2.

[0045] The nozzle 30 is connected to the downstream end of a supply pipe 31, and the upstream end of the supply pipe 31 is connected to a processing liquid supply source. In the example of Figure 3, the supply pipes 31 include a supply pipe 31c, a supply pipe 31w, and a supply pipe 31i.

[0046] The downstream end of the supply pipe 31c is connected to the nozzle 30c, and the upstream end of the supply pipe 31c is connected to a chemical supply source. The chemical supply source has a tank (not shown) that stores the chemical, and supplies the chemical to the upstream end of the supply pipe 31c. Examples of the chemical include hydrofluoric nitric acid obtained by mixing hydrofluoric acid, nitric acid, and water, a hydrofluoric acid-hydrogen peroxide solution (FPM) obtained by mixing hydrofluoric acid, hydrogen peroxide, and water, tetramethylammonium hydroxide (TMAH), a mixture of sulfuric acid and hydrogen peroxide (SPM), ammonia water, a mixture of ammonia, hydrogen peroxide, and water (SC-1), and a mixture of hydrogen chloride, hydrogen peroxide, and water (SC-2). The chemical does not have to be a mixture, but may be a single liquid. For example, a single liquid such as hydrofluoric acid (HF), hydrogen peroxide, or sulfuric acid can be used as the chemical.

[0047] The downstream end of supply pipe 31w is connected to nozzle 30w, and the upstream end of supply pipe 31w is connected to a rinse liquid supply source. The rinse liquid supply source has a tank (not shown) that stores the rinse liquid, and supplies the rinse liquid to the upstream end of supply pipe 31w. The rinse liquid may be, for example, pure water, carbon dioxide water, or ozone water.

[0048] The downstream end of the supply pipe 31i is connected to the nozzle 30i, and the upstream end of the supply pipe 31i is connected to a drying liquid supply source. The drying liquid supply source has a tank (not shown) that stores the drying liquid and supplies the drying liquid to the upstream end of the supply pipe 31i. For example, an organic solvent such as isopropyl alcohol can be used as the drying liquid. The surface tension of the drying liquid is lower than that of the other processing liquids (e.g., both the surface tension of the chemical liquid and the surface tension of the rinse liquid). Furthermore, the volatility of the drying liquid is higher than that of the other processing liquids (e.g., both the volatility of the chemical liquid and the volatility of the rinse liquid).

[0049] A supply valve 32 and a flow rate adjustment valve 33 are inserted in the supply pipe 31. In the example of Fig. 3, a supply valve 32c and a flow rate adjustment valve 33c are inserted in the supply pipe 31c, a supply valve 32w and a flow rate adjustment valve 33w are inserted in the supply pipe 31w, and a supply valve 32i and a flow rate adjustment valve 33i are inserted in the 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.

[0050] The discharge part 3 discharges various types of processing liquids in the order described below toward the first main surface Wa of the substrate W. This allows the processing unit 1 to sequentially perform various types of processing depending on the types of processing liquids on the first main surface Wa of the substrate W. Specific processing will be described later.

[0051] 3, the facing member 60 is configured to be able to discharge gas toward the first main surface Wa of the substrate W held by the substrate holding part 2. In the example of Fig. 3, the space in the hollow part of the facing member 60 other than the nozzle 30 functions as a gas flow path 30g. A lower end opening in the lower surface of the facing member 60 corresponds to the discharge port of the gas flow path 30g.

[0052] In the example of Figure 3, the upper part of the opposing member 60 is connected to the downstream end of a supply pipe 31g. In other words, the downstream end of the supply pipe 31g is connected to the gas flow path 30g. The upstream end of the supply pipe 31g is connected to a gas supply source. The gas supply source has a storage section (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, for example, at least one of nitrogen gas and a rare gas. The rare gas includes, for example, argon gas.

[0053] The supply pipe 31g is provided with a supply valve 32g, a flow rate adjustment valve 33g, and a heater 34g. The supply valve 32g switches the supply pipe 31g between on and off. 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 may be, for example, an electric resistance heater having an electric heating wire. The supply valve 32g, the flow rate adjustment valve 33g, and the heater 34g are controlled by a control unit 90.

[0054] When the supply valve 32g is opened and the heater 34g is activated, high-temperature inert gas is discharged from the center of the lower surface of the facing member 60 (i.e., the lower end opening of the gas flow path 30g) toward the center of the first main surface Wa of the substrate W. This can promote drying of the substrate W.

[0055] In the example of FIG. 3 , the processing unit 1 is provided with a movement driver 35. The movement driver 35 moves the discharge head, which includes the nozzles 30c, 30w, and 30i and the opposing member 60, as a unit. Specifically, the movement driver 35 moves the discharge head between a processing position and a standby position, which will be described below. The processing position is a position where the nozzles 30c, 30w, and 30i discharge the processing liquid toward the first main surface Wa of the substrate W, e.g., a position vertically opposite the center of the first main surface Wa of the substrate W. The processing position is also a position where the opposing member 60 discharges the inert gas toward the first main surface Wa of the substrate W. In the example of FIG. 3 , the discharge head is shown stopped at the processing position. The standby position is a position where the nozzles 30c, 30w, and 30i do not discharge the processing liquid toward the first main surface Wa of the substrate W, e.g., a position radially outward from the substrate holder 2. The standby position is also a position where the opposing member 60 does not discharge the inert gas toward the first main surface Wa of the substrate W.

[0056] FIG. 3 shows an example of a specific configuration of the movement drive unit 35. In the example of FIG. 3, the movement drive unit 35 includes an arm 351, a support column 352, and a drive source 353. The support column 352 is disposed radially outward of the guard 7 (described later) and extends vertically. The arm 351 extends horizontally, with its tip connected to the discharge head and its base connected to the support column 352. The drive source 353 is controlled by the control unit 90 and rotates the support column 352 in forward and reverse directions within a predetermined angular range around its central axis Q2. The drive source 353 includes, for example, a motor. When the support column 352 rotates in forward and reverse directions within a predetermined angular range around the central axis Q2, the discharge head reciprocates in the circumferential direction about the central axis Q2. The support column 352 is installed so that a processing position and a standby position are located on the movement trajectory of the discharge head. The movement drive unit 35 is not necessarily limited to the embodiment shown in FIG. 3, and may include a direct-acting mechanism such as a linear motor.

[0057] The substrate heating unit 4 heats the second main surface Wb of the substrate W held by the substrate holder 2. In the example of Fig. 3, the substrate heating unit 4 is provided at a position vertically opposite to the second main surface Wb of the substrate W. In the example of Fig. 3, the second main surface Wb of the substrate W corresponds to the bottom surface, and therefore the substrate heating unit 4 is provided directly below the substrate W. The substrate heating unit 4 heats at least a portion of the second main surface Wb of the substrate W to a temperature equal to or higher than the boiling point of the drying liquid. The technical significance of this will be described later.

[0058] In the example of FIG. 3 , the substrate heating unit 4 includes a nozzle 40. The nozzle 40 ejects a heat medium toward the second main surface Wb of the substrate W. In the example of FIG. 3 , the second main surface Wb of the substrate W corresponds to the bottom surface, so the nozzle 40 may also be called a bottom nozzle. In the example of FIG. 3 , a through hole is formed in the center of the spin base 21 of the substrate holding unit 2, and the shaft 231 is a hollow shaft. The through hole of the spin base 21 and the hollow portion of the shaft 231 are connected in the vertical direction. A portion of the nozzle 40 is disposed in the through hole. An ejection port is formed in the upper surface of the nozzle 40, and the ejection port of the nozzle 40 faces the center of the second main surface Wb of the substrate W in the vertical direction. The nozzle 40 ejects the heat medium toward the center of the second main surface Wb of the substrate W.

[0059] The downstream end of a supply pipe 41 is connected to the nozzle 40. 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 a more specific example is a liquid such as water. The heat medium supply source has, for example, a tank (not shown) that stores the heat medium, and supplies the heat medium to the upstream end of the supply pipe 41.

[0060] In the example of Fig. 3, a supply pipe 41 is provided with a supply valve 42, a flow rate adjustment valve 43, and a heater 44. The supply valve 42 switches the supply pipe 41 between on and off. The flow rate adjustment valve 43 adjusts the flow rate of the heat medium flowing through the supply pipe 41. The flow rate adjustment valve 43 may 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, an electric resistance heater having an electric heating wire. The supply valve 42, the flow rate adjustment valve 43, and the heater 44 are controlled by a control unit 90.

[0061] When the supply valve 42 is opened and the heater 44 is activated, a high-temperature heat medium is discharged from the nozzle 40 onto the central portion of the second main surface Wb of the substrate W. The heat medium that has landed on the central portion of the second main surface Wb of the substrate W is subjected to centrifugal force accompanying the rotation of the substrate W, flows radially outward along the second main surface Wb, and is scattered outward from the periphery of the substrate W. As 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.

[0062] In the example of FIG. 3 , the processing unit 1 is provided with a guard 7 and a guard lifting / lowering drive unit 71. The guard 7 has a cylindrical shape with the rotation axis Q1 as its central axis and surrounds the substrate holder 2. The guard 7 can catch the processing liquid and heat medium splashed from the periphery of the substrate W. The guard lifting / lowering drive unit 71 raises and lowers the guard 7 between an upper position and a lower position, which will be described below. The upper position is a position where the upper end of the guard 7 is vertically above the substrate W held by the substrate holder 2. When the guard 7 is in the upper position, it can catch the processing liquid and heat medium splashed 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 guard 7 is vertically below the upper surface of the spin base 21.

[0063] In the example of FIG. 3 , multiple guards 7 are provided. The multiple guards 7 are arranged concentrically. The multiple guards 7 may be used differently depending on the type of processing liquid. In the example of FIG. 3 , cups 72 are provided corresponding to each guard 7. The cups 72 have an annular (e.g., annular) recess (groove) surrounding the rotation axis Q1. Each cup 72 receives the processing liquid that has flowed down the inner circumferential surface of the corresponding guard 7. The upstream end of a discharge pipe 12 is connected to, for example, the bottom of each cup 72. The processing liquid received in each cup 72 is discharged to the outside of the processing unit 1 through the discharge pipe 12.

[0064] <Example of Operation of Substrate Processing Apparatus> Next, an example of operation of the processing unit 1 will be described. Fig. 4 is a flowchart showing an example of operation of the processing unit 1. The control unit 90 causes the processing unit 1 to perform processes from step S1 to step S7 in accordance with a preset processing procedure (recipe). Fig. 5 is a diagram schematically showing an example of the state of the processing unit 1 in a drying liquid supplying step described below.

[0065] First, the second transport part 122 transports the substrate W to the processing unit 1. Then, the substrate holding part 2 holds the substrate W received from the second transport part 122 (step S1: holding step). As a specific example, the substrate holding part 2 displaces the plurality of chuck pins 22 from their respective release positions to their holding positions. As a result, the plurality of chuck pins 22 hold the substrate W. The substrate holding part 2 continues to hold the substrate W until the processing on the substrate W is completed.

[0066] Next, the substrate holder 2 starts rotating the substrate W (step S2: rotation start step). The substrate holder 2 may continue rotating the substrate W until the processing of the substrate W is completed.

[0067] Next, the processing unit 1 supplies the chemical solution to the first main surface Wa of the substrate W (step S3: chemical process). First, the movement driver 35 moves the discharge head to the processing position. The guard lift driver 71 raises the chemical solution guard 7 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 a closed state to an open state. This causes the chemical solution to be discharged from the nozzle 30c toward the first main surface Wa of the rotating substrate W. The chemical solution that has landed on the first main surface Wa of the substrate W flows radially outward due to centrifugal force caused by the rotation of the substrate W and is scattered from the periphery of the substrate W. At this time, the chemical solution acts on the first main surface Wa of the substrate W, thereby performing chemical processing on the first main surface Wa of the substrate W according to the type of chemical solution. For example, the processing unit 1 performs a cleaning process to clean and remove impurities on the first main surface Wa of the substrate W, or an etching process to etch 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 received by the guard 7 and discharged to the outside of the chamber 10 through the discharge pipe 12 .

[0068] When the substrate W has been sufficiently processed, the control unit 90 closes the supply valve 32c. As a specific example, the control unit 90 measures the elapsed time from the start of the chemical discharge and determines whether the elapsed time is equal to or greater than a predetermined chemical time. The chemical time is set in advance to a time sufficient for the chemical process to be performed sufficiently. The elapsed time is measured, for example, by a timer circuit (not shown) belonging to the control unit 90. When the elapsed time is equal to or greater than the chemical time, the control unit 90 switches the supply valve 32c from an open state to a closed state.

[0069] Next, the processing unit 1 supplies a rinse liquid to the first main surface Wa of the substrate W (step S4: rinse step). If the guard 7 for the rinse liquid is different from the guard 7 for the chemical liquid, the guard lifting / lowering drive unit 71 appropriately raises and lowers the guard 7 to place the guard 7 for the rinse liquid 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 a closed state to an open state. This causes the rinse liquid to be ejected from the nozzle 30w toward the first main surface Wa of the rotating substrate W. The rinse liquid that has landed on the first main surface Wa of the substrate W flows radially outward due to centrifugal force caused by the rotation of the substrate W and is scattered from the periphery of the substrate W. At this time, the rinse liquid pushes the chemical liquid on the first main surface Wa of the substrate W radially outward. This replaces the processing liquid on the first main surface Wa of the substrate W with the rinse liquid. The processing liquid splashed from the periphery of the substrate W is received by the guard 7 and discharged to the outside of the chamber 10 through the discharge pipe 12 .

[0070] When the chemical liquid has been sufficiently replaced with the rinse liquid, the control unit 90 closes the supply valve 32w. As a specific example, the control unit 90 measures the elapsed time from the start of the discharge of the rinse liquid, and switches the supply valve 32w from the open state to the closed state when the elapsed time reaches or exceeds a predetermined rinse time. The rinse time is set in advance to a time sufficient to replace the chemical liquid with the rinse liquid.

[0071] Next, the processing unit 1 supplies a drying liquid to the first main surface Wa of the substrate W (step S5: drying liquid supply step). If the guard 7 for the drying liquid is different from the guard 7 for the rinsing liquid, the guard lifting / lowering drive unit 71 raises and lowers the guard 7 appropriately to raise the guard 7 for the drying liquid 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 a closed state to an open state.

[0072] When the supply valve 32i opens, as shown in Fig. 5, the drying liquid is discharged from the discharge port 3i of the nozzle 30i toward the first main surface Wa of the rotating substrate W. The temperature of the drying liquid may be, for example, room temperature (e.g., about 25°C). The temperature of the drying liquid here refers to, for example, the temperature of the drying liquid at the discharge port 3i. Furthermore, the room temperature here includes, for example, the temperature of the drying liquid when a heater for heating the drying liquid is not provided upstream of the discharge port 3i or when the heater is not operating. In other words, the room temperature includes the temperature of the drying liquid that is not heated.

[0073] The drying liquid from the nozzle 30i lands on the center of the first main surface Wa of the substrate W. The drying liquid that has landed on the first main surface Wa flows radially outward due to centrifugal force caused by the rotation of the substrate W and splashes off from the periphery of the substrate W. At this time, the drying liquid pushes away the rinsing liquid on the first main surface Wa of the substrate W, thereby replacing the processing liquid on the first main surface Wa of the substrate W from the rinsing liquid with the drying liquid. The processing liquid that has splashed off from the periphery of the substrate W is received by the guard 7 and discharged to the outside of the chamber 10 through the discharge pipe 12.

[0074] Here, the rotation speed of the substrate W in the drying liquid supplying step may be set to, for example, 150 rpm or more and 600 rpm or less, or 200 rpm or more and 400 rpm or less. As a more specific example, the rotation speed may be set to 300 rpm.

[0075] Furthermore, the processing unit 1 heats the second main surface Wb of the substrate W while supplying the drying liquid. That is, the substrate heating section 4 heats the second main surface Wb of the substrate W. As a more specific example, the control section 90 opens the supply valve 42 and activates the heater 44. As a result, as shown in FIG. 5 , a high-temperature heat medium (e.g., hot water) is ejected from the nozzle 40 toward the center of the second main surface Wb of the rotating substrate W. The heat medium that has landed in the center of the second main surface Wb of the substrate W flows radially outward due to centrifugal force caused by the rotation of the substrate W and is scattered from the periphery of the substrate W. As 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, heating the substrate W. The heat of the substrate W is transferred to the drying liquid on the first main surface Wa. As a result, the drying liquid on the first main surface Wa of the substrate W is also heated and its temperature increases.

[0076] The substrate heating unit 4 heats the second main surface Wb of the substrate W so that the temperature of at least a portion (here, the center) of the second main surface Wb of the substrate W is equal to or higher than the boiling point of the drying liquid. For example, the heater 44 heats the heat medium (hereinafter also referred to as the medium temperature) so that the temperature of the heat medium is equal to or higher than the boiling point of the drying liquid. The medium temperature of the heat medium here refers to, for example, the temperature of the heat medium at the outlet of the nozzle 40. When the drying liquid is isopropyl alcohol, the boiling point is 82.4°C, and the medium temperature of the heat medium is set to, for example, approximately 85°C. However, the medium temperature of the heat medium can be set below the boiling point of the heat medium. For example, when the heat medium is water, the temperature may be set to less than 90°C, which is 10°C lower than the boiling point (100°C). This allows compliance with SEMI standards.

[0077] The flow rate control valve 43 may 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 control valve 43 may adjust the flow rate of the heat medium to 1000 mL / min or more, or 1500 mL / min or more.

[0078] The nozzle 30i ejects drying liquid that is at a lower temperature than the heat medium. Therefore, low-temperature drying liquid is continuously supplied to the first main surface Wa of the substrate W. Therefore, the low-temperature drying liquid can cool the first main surface Wa of the substrate W. The cooling capacity of this drying liquid increases as the flow rate of the drying liquid increases. Therefore, the flow rate adjustment valve 33i adjusts the flow rate of the drying liquid to a value that will cause the temperature of the first main surface Wa of the substrate W to be below its boiling point. For example, the flow rate of the drying liquid is preset to approximately 100 mL / min or more, and more specifically, can be set to 250 mL / min or more.

[0079] As described above, in the drying liquid supply process, the processing unit 1 heats at least a portion of the second main surface Wb of the substrate W above the boiling point of the drying liquid, while supplying the drying liquid to the first main surface Wa of the substrate W at a flow rate such that the temperature of the first main surface Wa of the substrate W is below the boiling point of the drying liquid.

[0080] Once the rinsing liquid has been sufficiently replaced with the drying liquid, the processing unit 1 dries the substrate W (step S6: drying step). Specifically, the processing unit 1 measures the elapsed time from the start of the drying liquid discharge and determines whether the elapsed time is equal to or longer than a predetermined drying liquid supply time. The drying liquid supply time is preset to a time sufficient to completely replace the rinsing liquid with the drying liquid. The drying liquid supply time is set, for example, to at least several tens of seconds, and as a specific example, may be set to approximately 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. Furthermore, the substrate heater 4 stops heating the second main surface Wb of the substrate W.

[0081] Furthermore, the control unit 90 controls the substrate holding unit 2 to increase the rotation speed of the substrate W. For example, the substrate holding unit 2 may rotate the substrate W at a rotation speed of 800 rpm or more and 2500 rpm or less, or may rotate the substrate W at a rotation speed of 800 rpm or more and 1500 rpm or less. Alternatively, the substrate holding unit 2 may gradually (for example, stepwise) increase the rotation speed of the substrate W.

[0082] The processing unit 1 may supply inert gas toward the center of the first main surface Wa of the substrate W. Specifically, the control unit 90 may open the supply valve 32g and operate the heater 34g. This causes high-temperature inert gas to be discharged toward the center of the first main surface Wa of the substrate W from a gas discharge port in the center of the lower surface of the facing member 60 (i.e., the lower end port of the gas flow path 30g). The inert gas that hits the center of the first main surface Wa of the substrate W flows radially outward along the first main surface Wa. The heater 34g may heat the inert gas to, for example, 60°C or higher, 70°C or higher, or 80°C or higher. The temperature of the inert gas may be, for example, the temperature of the inert gas at the gas discharge port of the gas flow path 30g. The flow rate adjustment valve 33g may adjust the flow rate of the inert gas to, for example, 10 L / min or higher and 300 L / min or lower.

[0083] When the drying liquid has sufficiently evaporated, the processing unit 1 stops the discharge of the inert gas and stops the rotation of the substrate W. As a specific example, the control unit 90 measures the elapsed time since the discharge of the drying liquid stopped and determines whether the measured time is equal to or longer than a predetermined drying time. The drying time is set in advance to a time sufficient for the substrate W to be sufficiently dried. When the elapsed time is equal to or longer than the drying time, the control unit 90 switches the supply valve 32g from an open state to a closed state and causes the substrate holder 2 to stop the rotation of the substrate W. In addition, the movement drive unit 35 moves the discharge head to the standby position, and the guard lift drive unit 71 lowers the guard 7 to the lower position.

[0084] Next, the substrate holder 2 releases the hold on the substrate W (step S7: hold releasing step).Then, the second transporter 122 carries the processed substrate W out of the processing unit 1.

[0085] As described above, the processing unit 1 can process the substrate W. Moreover, in this embodiment, the substrate heating unit 4 heats the substrate W in a drying liquid supply step that follows a liquid supply step that includes a chemical liquid step and a rinsing step. FIG. 6 is a timing chart of the processing unit 1, and is a diagram schematically illustrating an example of the change in the medium temperature of the heat medium over time and the change in the temperature of the first main surface Wa of the substrate W over time. Hereinafter, the temperature of the first main surface Wa of the substrate W will also be referred to as the substrate temperature. In the example of FIG. 6, graphs G1 to G5 show substrate temperatures at different radial positions on the first main surface Wa of the substrate W. The smaller the number on each of the symbols in graphs G1 to G5, the closer the substrate is to the rotation axis Q1. That is, graph G1 shows the substrate temperature at the most central position on the first main surface Wa of the substrate W, and graph G5 shows the substrate temperature at the most peripheral position on the first main surface Wa of the substrate W.

[0086] 6 , the control unit 90 switches the supply valve 32i from a closed state to an open state at time t1. As a result, drying liquid begins to be discharged from the nozzle 30i toward the first main surface Wa of the substrate W. At this time t1, the drying liquid supplying step essentially begins. Also, the control unit 90 switches the supply valve 42 from a closed state to an open state, for example, at time t1, and activates the heater 44. As a result, a high-temperature heat medium is discharged from the nozzle 40 toward the second main surface Wb of the substrate W, thereby heating the substrate W. In the example of FIG. 6 , the medium temperature of the heat medium discharged from the nozzle 40 is higher than the boiling point bp of the drying liquid.

[0087] When the heat medium begins to be discharged, the substrate temperature at each position on the first main surface Wa of the substrate W increases over time. The substrate temperature increases at a high rate up to a certain point, and then may increase gradually or converge. As shown in FIG. 6 , the substrate temperature at each position on the first main surface Wa of the substrate W is lower than the boiling point bp of the drying liquid. This is because, as described above, the flow rate control valve 33i adjusts the flow rate of the drying liquid so that the substrate temperature is below the boiling point bp of the drying liquid. In the example of FIG. 6 , the heat medium lands at the center of the second main surface Wb of the substrate W, so the substrate temperature on the first main surface Wa of the substrate W has a temperature distribution described below. That is, as shown in FIG. 6 , the substrate temperature is high at the center of the substrate W and decreases radially outward.

[0088] At time t2, which is later than time t1, the control unit 90 switches the supply valves 32i and 42 from the open state to the closed state. In other words, the drying liquid supplying process essentially ends at time t2. The substrate temperature at the center of the first main surface Wa at time t2 may be, for example, 70°C or higher, e.g., approximately 80°C. The substrate temperature at the peripheral edge of the first main surface Wa at time t2 may be, for example, 60°C or higher, e.g., approximately 70°C.

[0089] As described above, the substrate temperature during the drying liquid supplying step is below the boiling point bp of the drying liquid. This makes it possible to more reliably suppress boiling of the drying liquid during the drying liquid supplying step. If the drying liquid on the first main surface Wa of the substrate W boils during the supply of the drying liquid, this will result in particles adhering to the first main surface Wa. In this embodiment, the boiling of the drying liquid is more reliably suppressed, making it possible to more reliably suppress particles adhering to the first main surface Wa of the substrate W.

[0090] Moreover, in the drying liquid supplying step, the temperature of at least a part of the second main surface Wb of the substrate W is equal to or higher than the boiling point bp of the drying liquid. Therefore, in the drying liquid supplying step, the maximum value in the temperature distribution on the first main surface Wa of the substrate W can be brought closer to the boiling point bp. The minimum value in the temperature distribution on the first main surface Wa of the substrate W in the drying liquid supplying step (i.e., the substrate temperature at the peripheral portion of the first main surface Wa) is, for example, 60 degrees Celsius or higher. In other words, the flow rate of the drying liquid can be set so that the substrate temperature at each position on the first main surface Wa of the substrate W is 60 degrees Celsius or higher and lower than the boiling point bp of the drying liquid.

[0091] For this reason, in this embodiment, in the drying liquid supplying step, the temperature of the drying liquid on the first main surface Wa of the substrate W can be brought closer to the boiling point bp. Therefore, in the drying step immediately after the supply of the drying liquid is stopped, the temperature of the drying liquid can be made higher. Therefore, in the drying step, the surface tension of the drying liquid can be further reduced and the evaporation rate of the drying liquid can be further increased. By reducing the surface tension, the collapse rate of the pattern can be effectively reduced. Furthermore, since the drying liquid can be evaporated in a shorter time, the impulse on the pattern due to the surface tension of the drying liquid during evaporation can also be reduced. This also effectively reduces the collapse rate of the pattern.

[0092] Furthermore, the substrate heating unit 4 supplies the heat medium to the second main surface Wb of the substrate W to heat the substrate W. In this way, the substrate heating unit 4 can heat at least a part of the second main surface Wb of the substrate W to a temperature equal to or higher than the boiling point of the drying liquid with a simple configuration.

[0093] Although the discharge unit 3 discharges the drying liquid at room temperature in the above example, it may also discharge high-temperature drying liquid. For example, the discharge unit 3 may further include a heater (not shown). The heater is provided in the supply pipe 31i and heats the drying liquid flowing through the supply pipe 31i. The heater is controlled by the control unit 90. The heater heats the drying liquid so that the temperature of the drying liquid is higher than room temperature and lower than the boiling point bp of the drying liquid. For example, the heater may raise the temperature of the drying liquid to 60°C or higher, and as a specific example, it may raise the temperature to about 70°C.

[0094] Second Embodiment It has been found that the pattern collapse rate tends to be higher in the peripheral portion than in the central portion of the first main surface Wa of the substrate W. Therefore, the second embodiment aims to reduce the pattern collapse rate particularly in the peripheral portion of the first main surface Wa of the substrate W.

[0095] An example of the configuration of the substrate processing apparatus 100 according to the second embodiment is similar to that of the first embodiment. However, the specific configuration of the substrate heating section 4 of the processing unit 1 differs from that of the first embodiment. FIG. 7 is a diagram schematically illustrating a first example of the substrate heating section 4 according to the second embodiment. FIG. 7 also illustrates a substrate W held by a substrate holder 2. In the example of FIG. 7, the substrate heating section 4 is provided at a position vertically opposite to a peripheral portion of the second main surface Wb of the substrate W held by the substrate holder 2. The substrate heating section 4 heats the peripheral portion of the second main surface Wb of the substrate W to a temperature equal to or higher than the boiling point bp of the drying liquid.

[0096] FIG. 8 is a diagram schematically illustrating a first example of the configuration of a portion of the processing unit 1 according to the second embodiment. In the example of FIG. 8 , the substrate heating unit 4 includes a discharge pipe 45 instead of the nozzle 40. The discharge pipe 45 is provided directly below the substrate W held by the substrate holding unit 2. Specifically, the discharge pipe 45 is provided between the substrate W held by the substrate holding unit 2 and the spin base 21. The discharge pipe 45 extends radially, and its upstream end is connected to the downstream end of the supply pipe 41. The downstream end of the discharge pipe 45 is located radially inward of the chuck pins 22 of the substrate holding unit 2. The discharge pipe 45 has a discharge port 4a formed therein that faces a peripheral portion of the second main surface Wb of the substrate W in the vertical direction. A heat medium is discharged from the discharge port 4a of the discharge pipe 45, and the heat medium lands on the peripheral portion of the second main surface Wb of the substrate W. The heat medium that has landed on the second main surface Wb moves radially outward as the substrate W rotates, and is scattered outward from the periphery of the substrate W. As a result, the substrate heating unit 4 heats the periphery of the second main surface Wb of the substrate W. The distance between the position where the heat medium landed on the second main surface Wb and the rotation axis Q1 may be 60% or more, 70% or more, 80% or more, or 90% or more of the radius of the substrate W.

[0097] As in the first embodiment, the substrate heating unit 4 supplies a heat medium at or above the boiling point bp of the drying liquid to the second main surface Wb of the substrate W. The medium temperature of the heat medium is, for example, about 85°C. The substrate heating unit 4 can heat the peripheral portion of the second main surface Wb of the substrate W to or above the boiling point bp of the drying liquid. The temperature of the first main surface Wa of the substrate W decreases with increasing radial distance from the contact position of the heat medium.

[0098] An example of the operation of the processing unit 1 according to the first example of the second embodiment is similar to that shown in the flowchart of Fig. 4. However, in the second embodiment, in the drying liquid supplying step (step S5), the substrate heating part 4 heats the peripheral portion of the second main surface Wb of the substrate W to a temperature equal to or higher than the boiling point bp of the drying liquid. In other words, the central portion of the second main surface Wb of the substrate W is not heated very much.

[0099] Also, as in the first embodiment, in the drying liquid supply process, the processing unit 1 supplies the drying liquid to the first main surface Wa of the substrate W at a flow rate that makes the temperature of the first main surface Wa of the substrate W less than the boiling point bp of the drying liquid.

[0100] As described above, in the first example of the second embodiment, the substrate heating unit 4 heats the peripheral portion of the second main surface Wb of the substrate W, thereby enabling a concentrated increase in the temperature of the peripheral portion of the first main surface Wa of the substrate W. For example, the substrate temperature at the peripheral portion (liquid landing position) of the first main surface Wa of the substrate W can be increased to approximately 80°C.

[0101] Therefore, in the drying step immediately after the supply of the drying liquid is stopped, the temperature of the drying liquid on the peripheral portion of the first main surface Wa of the substrate W can be increased. Therefore, in the drying step, the surface tension of the drying liquid on the peripheral portion can be further reduced, and the evaporation rate of the drying liquid on the peripheral portion can be further increased. This effectively reduces the rate of pattern collapse on the peripheral portion of the first main surface Wa of the substrate W.

[0102] As described above, the pattern collapse rate in the peripheral portion tends to be higher than the pattern collapse rate in the central portion, so by reducing the pattern collapse rate in the peripheral portion, the pattern collapse rate over the entire first main surface Wa of the substrate can be reduced.

[0103] FIG. 9 is a schematic diagram illustrating a second example of the substrate heating unit 4 according to the second embodiment. FIG. 9 also illustrates a substrate W held by the substrate holder 2. In the example of FIG. 9, the substrate heating unit 4 includes a peripheral heating unit 4A and a central heating unit 4B. The peripheral heating unit 4A is provided at a position vertically facing the peripheral portion of the second main surface Wb of the substrate W held by the substrate holder 2. The peripheral heating unit 4A heats the peripheral portion of the second main surface Wb of the substrate W to a temperature equal to or higher than the boiling point bp of the drying liquid. The central heating unit 4B is provided radially inward of the peripheral heating unit 4A and at a position vertically facing the central portion of the second main surface Wb of the substrate W. The central heating unit 4B heats the central portion of the second main surface Wb of the substrate W. The central heating unit 4B heats the central portion of the second main surface Wb of the substrate W, for example, to a temperature lower than the peripheral portion of the second main surface Wb.

[0104] 10 is a diagram schematically illustrating a second example of the configuration of a portion of the processing unit 1 according to the second embodiment. In the example of FIG. 10, the peripheral heating unit 4A supplies a heat medium to the peripheral portion of the second main surface Wb of the substrate W, and the central heating unit 4B supplies the heat medium to the central portion of the second main surface Wb of the substrate W. The peripheral heating unit 4A and the central heating unit 4B can supply the heat medium at different medium temperatures. In the example of FIG. 10, the peripheral heating unit 4A includes a supply pipe 41A, a supply valve 42A, a flow rate adjustment valve 43A, a heater 44A, and an outlet pipe 45. The supply pipe 41A, the supply valve 42A, the flow rate adjustment valve 43A, and the heater 44A are similar to the supply pipe 41, the supply valve 42, and the heater 44, respectively, of FIG. 8. 10, central heating unit 4B includes a supply pipe 41B, a supply valve 42B, a flow rate adjustment valve 43B, a heater 44B, and a nozzle 40. Supply pipe 41B, supply valve 42B, flow rate adjustment valve 43B, and heater 44B are similar to supply pipe 41, supply valve 42, and heater 44 in FIG. 3, respectively. Parts of supply pipe 41A and supply pipe 41B are provided adjacent to each other in the hollow portion of shaft 231.

[0105] The heater 44A heats the heat medium so that the first medium temperature of the heat medium discharged from the discharge port 4a of the outlet pipe 45 is equal to or higher than the boiling point bp of the drying liquid. The heater 44B heats the heat medium so that the second medium temperature of the heat medium discharged from the discharge port of the nozzle 40 is lower than the first medium temperature, for example. The first medium temperature may be, for example, about 85°C, and the second medium temperature may be, for example, about 70°C.

[0106] An example of the operation of the processing unit 1 according to the second example of the second embodiment is similar to the flowchart of FIG. 4 . However, in the second example of the second embodiment, in the drying liquid supply step (step S5), the substrate heater 4 heats the peripheral portion of the second main surface Wb of the substrate W (at least the position where the heat medium is applied) to a temperature equal to or higher than the boiling point bp of the drying liquid, while heating the central portion of the second main surface Wb of the substrate W to a temperature lower than that of the peripheral portion (e.g., a temperature lower than the boiling point bp). Specifically, in the drying liquid supply step, the controller 90 opens the supply valves 42A and 42B. Furthermore, the heater 44A heats the heat medium so that the first medium temperature of the heat medium is equal to or higher than the boiling point bp of the drying liquid, and the heater 44B heats the heat medium so that the second medium temperature of the heat medium is lower than the first medium temperature. The second medium temperature is, for example, lower than the boiling point bp.

[0107] On the other hand, the substrate temperature at the center of the first main surface Wa of the substrate W is, for example, about 70° C., and the substrate temperature at the peripheral portion of the first main surface Wa of the substrate W is, for example, about 80° C. Here, the substrate temperature at the center of the first main surface Wa of the substrate W is, for example, the substrate temperature at a position vertically opposite to the position where the heat medium from the nozzle 40 lands, and the substrate temperature at the peripheral portion is, for example, the substrate temperature at a position vertically opposite to the position where the heat medium from the outlet pipe 45 lands.

[0108] As described above, in the second example of the second embodiment, the substrate heating unit 4 also heats the peripheral portion of the second main surface Wb of the substrate W. As a result, the substrate temperature at the peripheral portion (liquid landing position) of the first main surface Wa of the substrate W can be raised to approximately 80° C. This can reduce the rate of pattern collapse at the peripheral portion of the first main surface Wa of the substrate W.

[0109] In the second example of the second embodiment, the substrate heating section 4 also heats the central portion of the second main surface Wb of the substrate W. However, the substrate temperature in the central portion of the first main surface Wa of the substrate W is lower than the substrate temperature in the peripheral portion. Because the pattern collapse rate tends to be lower in the peripheral portion of the substrate W, even if the substrate temperature in the central portion is lower than the substrate temperature in the peripheral portion, the pattern collapse rate in the central portion can be sufficiently reduced. Furthermore, because the central portion of the substrate W is not excessively heated, the power consumption of the substrate heating section 4 can be reduced. In other words, the processing unit 1 can reduce the pattern collapse rate in the central portion of the first main surface Wa of the substrate W while reducing power consumption, thereby further reducing the overall pattern collapse rate.

[0110] Furthermore, the substrate heating part 4 supplies the heat medium at the first medium temperature to the peripheral portion of the second main surface Wb of the substrate W, and supplies the heat medium at the second medium temperature to the central portion of the second main surface Wb of the substrate W. Therefore, the processing unit 1 can reduce the collapse rate of the entire pattern on the first main surface Wa of the substrate W with a simple configuration.

[0111] In the above example, the substrate heating unit 4 includes the peripheral heating unit 4A and the central heating unit 4B, but may include three or more heating units. The three or more heating units may be arranged side by side in the radial direction. The three or more heating units heat different radial portions of the second main surface Wb of the substrate W. In this case, the heating unit located closer to the peripheral portion of the substrate W may heat the corresponding portion of the second main surface Wb of the substrate W to a higher temperature.

[0112] In the first and second embodiments, the substrate heating unit 4 heats the second main surface Wb of the substrate W throughout the entire drying liquid supply time in the drying liquid supply step (step S5). However, this is not necessarily limited to this.

[0113] FIG. 11 is a diagram schematically illustrating an example of a timing chart of the processing unit 1 according to the third embodiment. In the example of FIG. 11 , at time t1, the control unit 90 switches the supply valve 32i from the closed state to the open state. As a result, the drying liquid begins to be discharged from the nozzle 30i toward the first main surface Wa of the substrate W. In other words, the drying liquid supplying step essentially begins at time t1. On the other hand, in the example of FIG. 11 , at time t12, which is later than time t1, the control unit 90 switches the supply valve 42 from the closed state to the open state. As a result, the high-temperature heat medium begins to be discharged from the nozzle 40 toward the second main surface Wb of the substrate W. In other words, the substrate heating unit 4 begins to heat the second main surface Wb of the substrate W. Then, at time t2, which is later than time t12, the control unit 90 switches the supply valve 32i and the supply valve 42 from the open state to the closed state. In other words, the drying liquid supplying step essentially ends at time t2.

[0114] As described above, in the third embodiment, during the drying liquid supply time T from time t1 to time t2, the substrate heating unit 4 does not heat the second main surface Wb of the substrate W during the predetermined early time T1 from time t1 to time t12, but heats the second main surface Wb of the substrate W during the predetermined late time T2 from time t12 to time t2. The late time T2 is set in advance to a time sufficient to bring the temperature of the first main surface Wa of the substrate W at time t2 close to the boiling point bp of the drying liquid. For example, the late time T2 may be set to half or less of the drying liquid supply time T, or to one-third or less, or to one-quarter or less, or to one-tenth or less of the drying liquid supply time T.

[0115] As described above, in the third embodiment, the substrate heating section 4 does not heat the substrate W during the previous time T1, but heats the second main surface Wb of the substrate W during the subsequent time T2. That is, the substrate heating section 4 heats the second main surface Wb of the substrate W only during the subsequent time T2. This shortens the operating time of the substrate heating section 4, thereby reducing the power consumption of the substrate processing apparatus 100. Furthermore, when the substrate heating section 4 supplies a high-temperature heat medium to the second main surface Wb of the substrate W, the amount of heat medium used can be reduced. When the heat medium is liquid, liquid saving can be achieved.

[0116] In the above example, the processing unit 1 performs the chemical step (step S3), the rinsing step (step S4), the drying liquid supply step (step S5), and the drying step (step S6) in this order. However, this is not necessarily limited to this.

[0117] 12 is a flowchart showing a first example of the operation of the processing unit 1 according to the fourth embodiment. In the example of FIG. 12, the control unit 90 causes the processing unit 1 to perform processes from step S11 to step S19 in accordance with a preset processing procedure (recipe). Steps S11 to S15 are similar to steps S1 to S5, respectively. However, in step S15 (drying liquid supply step), the substrate heating unit 4 does not have to heat the substrate W.

[0118] Next, the processing unit 1 hydrophobizes the first main surface Wa of the substrate W (corresponding to step S16: hydrophobization process: 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 silylation liquid that includes a liquid silylation agent (also called a silane coupling agent). The processing unit 1 stops ejecting the hydrophobizing liquid from the nozzle when the first main surface Wa of the substrate W has been sufficiently hydrophobized.

[0119] Next, the processing unit 1 executes steps S17 to S19, which are similar to steps S5 to S7, respectively.

[0120] As described above, in the first example described above, the drying liquid supplying step (step S17) is performed in the same manner as the drying liquid supplying step (step S5) in the first to third embodiments. This makes it possible to reduce the collapse rate of the pattern on the substrate W. Moreover, since the first main surface Wa of the substrate W is hydrophobized, the contact angle of the first main surface Wa can be reduced. This makes it possible to reduce the surface tension acting on the pattern, further reducing the collapse rate of the pattern.

[0121] FIG. 13 is a flowchart showing a second example of the operation of the processing unit 1 according to the fourth embodiment. In the example of FIG. 13 , the control unit 90 causes the processing unit 1 to perform steps S21 to S26 according to a preset processing procedure (recipe). Steps S21 to S26 are similar to steps S1 to S3 and steps S5 to S7, respectively. However, at the end of step S23 (chemical liquid step: corresponding to the liquid supply step), metal is exposed on the first main surface Wa of the substrate W. In the second example, step S24 (drying liquid supply step) is performed after step S23. Therefore, water is not supplied to the first main surface Wa of the substrate W. This prevents a reaction between metal and water, thereby avoiding problems caused by the reaction. Furthermore, in the second example described above, the drying liquid supply step (step S24) is performed in the same manner as the drying liquid supply step (step S5) in the first to third embodiments. This reduces the rate of pattern collapse on the substrate W.

[0122] Fifth Embodiment FIG. 14 is a diagram schematically illustrating an example of the configuration of a processing unit 1 according to a fifth embodiment. The processing unit 1 according to the fifth embodiment differs from the processing unit 1 according to the first embodiment in the configuration of the discharge unit 3 and the opposing member 60. In the example of FIG. 14 , the opposing member 60 includes a shielding plate 6 and a hollow shaft 61. The shielding plate 6 is provided at a position vertically opposing the first main surface Wa of the substrate W held by the substrate holder 2. In the example of FIG. 14 , the first main surface Wa of the substrate W corresponds to the upper surface, and therefore the shielding plate 6 is provided vertically above the substrate W. The shielding plate 6 has, for example, a plate-like shape and is provided with its thickness direction aligned vertically. The lower surface of the shielding plate 6 is the surface opposing the first main surface Wa of the substrate W. The shielding plate 6 has, for example, a circular shape in a plan view. The diameter of the shielding plate 6 (i.e., the diameter of the opposing surface) may be, for example, 80% or more of the diameter of the substrate W, 90% or more, or even greater than the diameter of the substrate W.

[0123] In the example of Figure 14, a hollow shaft 61 is provided on the upper surface of the blocking plate 6. The hollow shaft 61 has a hollow portion, and a through-hole that passes vertically through the blocking plate 6 is formed in the center of the blocking plate 6. The hollow portion is vertically connected to the through-hole of the blocking plate 6. The nozzle 30i is provided in the hollow portion of the hollow shaft 61 and the through-hole of the blocking plate 6. The diameter of the outer peripheral surface of the nozzle 30i is smaller than the diameters of the inner peripheral surfaces of the hollow shaft 61 and the blocking plate 6. The space between the outer peripheral surface of the nozzle 30i and the inner peripheral surfaces of the hollow shaft 61 and the blocking plate 6 functions as a gas flow path 30g.

[0124] 14, nozzle 30c and nozzle 30w are provided outside opposing member 60. Also, in the example of Fig. 14, movement drive unit 35c and movement drive unit 35w are provided as movement drive unit 35. Movement drive unit 35c moves nozzle 30c between the processing position and the standby position, and movement drive unit 35w moves nozzle 30w between the processing position and the standby position.

[0125] In the example of FIG. 14 , a movement drive unit 35i is provided as the movement drive unit 35. The movement drive unit 35i moves the nozzle 30i and the opposing member 60 together. The movement drive unit 35i moves the nozzle 30i and the opposing member 60 together, for example, in the vertical direction. In this case, the movement drive unit 35i can also be said to be an elevation drive unit. The movement drive unit 35i includes a drive source such as a motor and a power transmission unit that transmits power from the drive source to the nozzle 30i and the shielding plate 6. The power transmission unit includes, for example, a cam mechanism or a ball screw mechanism.

[0126] The operation of the processing unit 1 according to the fifth embodiment is similar to that shown in the flowchart of Fig. 4. However, the movement driver 35i lowers the nozzle 30i and the opposing member 60 to a processing position closer to the substrate W in the drying liquid supplying step and the drying step, and raises them to a standby position higher than the processing position in other steps.

[0127] In the fifth embodiment, the drying liquid supplying step (step S5) in the first to third embodiments is also performed, so that the rate of pattern collapse at the peripheral edge of the substrate W can be reduced.

[0128] Although the substrate processing apparatus 100 and the substrate processing method have been described in detail above, the above description is merely an example in all respects, and this disclosure is not limited thereto. Furthermore, the various modifications described above can be combined and applied as long as they are not mutually inconsistent. It is understood that many modifications not illustrated can be envisioned without departing from the scope of this disclosure.

[0129] In the above example, a dedicated nozzle is provided for each fluid, but one nozzle may be shared by different types of fluids.

[0130] Furthermore, although in the above example, the substrate heating unit 4 supplies a heat medium to the second main surface Wb of the substrate W, this is not necessarily limited to this. The substrate heating unit 4 may include, for example, a heater provided at a position vertically facing the second main surface Wb of the substrate W. The heater may be, for example, an electric resistance heater including an electric heating wire, or an optical heater that outputs heating light. For example, the peripheral heating unit 4A may be an electric resistance heater or an optical heater. The peripheral heating unit 4A may be provided so as to surround the rotation axis Q1. The central heating unit 4B may also be an electric resistance heater or an optical heater.

[0131] bp Boiling point S1 Holding step (step) S4, S16, S23 Liquid supply step (step) S5, S17, S24 Drying liquid supply step (step) S6, S18, S25 Drying step (step) T Drying liquid supply time T1 Pre-time T2 Post-time W Substrate Wa First main surface Wb Second main surface

Claims

1. A substrate processing method comprising: a holding step of holding a substrate having a first main surface on which a pattern is formed and a second main surface opposite to the first main surface; a liquid supplying step of supplying a processing liquid to the first main surface of the substrate; a drying liquid supplying step of supplying the drying liquid to the first main surface of the substrate at a flow rate such that the temperature of the first main surface of the substrate is below the boiling point of the drying liquid while heating at least a portion of the second main surface of the substrate to a temperature equal to or higher than the boiling point of the drying liquid after the liquid supplying step; and a drying step of drying the substrate after the drying liquid supplying step.

2. A substrate processing method according to claim 1, wherein in the drying liquid supplying step, a heat medium having a boiling point equal to or higher than the boiling point of the drying liquid is supplied to the second main surface of the substrate.

3. A substrate processing method according to claim 1 or 2, wherein in the drying liquid supplying step, a peripheral portion of the second main surface of the substrate is heated to a temperature equal to or higher than the boiling point of the drying liquid.

4. A substrate processing method as defined in claim 3, wherein in the drying liquid supplying step, a central portion of the second main surface of the substrate is heated to a temperature lower than a temperature of the peripheral portion of the second main surface.

5. A substrate processing method as described in claim 4, wherein, in the drying liquid supply step, a heat medium at a first medium temperature is supplied to the peripheral portion of the second main surface of the substrate, and a heat medium at a second medium temperature lower than the first medium temperature is supplied to the central portion of the second main surface of the substrate.

6. A substrate processing method according to claim 1 or 2, wherein, in the drying liquid supply step, the second main surface of the substrate is heated only during a latter period of a drying liquid supply time during which the drying liquid is supplied.

7. A substrate processing method according to claim 1 or 2, wherein in the drying liquid supplying step, the temperature of the first main surface of the substrate is equal to or higher than 60 degrees Celsius and lower than the boiling point of the drying liquid.

Images