JP7537937B2 - SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD - Google Patents

Description

The present invention relates to a substrate processing apparatus and a substrate processing method for drying a substrate, such as a semiconductor wafer, a substrate for a liquid crystal display device, or a flat panel display (FPD) such as an organic electroluminescence (EL) display device.
These include substrates for displays, optical disks, magnetic disks, magneto-optical disks, photomasks, ceramic substrates, and solar cell substrates.

The manufacturing process for electronic components such as semiconductor devices and liquid crystal display devices includes a process of repeatedly performing processes such as film formation and etching on the surface of a substrate to form a pattern. After this pattern is formed, a cleaning process using a chemical solution, a rinsing process using a rinsing solution, and a drying process are performed in that order, but the importance of the drying process is increasing as patterns become finer. In other words, technology that suppresses or prevents the occurrence of pattern collapse during the drying process is becoming important. Therefore, as described in Patent Document 1, for example, a substrate processing apparatus and a substrate processing method have been proposed that dry a substrate using a sublimable substance that changes into a gas without passing through a liquid state.

JP 2020-4948 A

In the substrate processing technology described in Patent Document 1, a solution containing a sublimable substance such as camphor and a solvent that dissolves in the sublimable substance is prepared as a pre-drying treatment liquid. The pre-drying treatment liquid is supplied to the surface of a substrate on which a pattern has been formed. This causes a liquid film of the pre-drying treatment liquid to be formed on the surface of the substrate with a desired thickness. After this, the solvent is removed by vaporization from the liquid film, forming a solid film (corresponding to an example of the "solidified body" of the present invention) made of the sublimable substance over the entire surface of the substrate. The solid film is then removed from the surface of the substrate by sublimation.

In conventional technology, no special attention was paid to the atmosphere in contact with the pre-drying treatment liquid on the surface of the substrate during the period in which the pre-drying treatment liquid is supplied to the surface of the substrate to form the desired liquid film (hereinafter referred to as the "liquid film formation period"). As a result, conventional technology has difficulty meeting more advanced drying requirements, and there are certain limitations to high-quality drying.

This invention was developed in consideration of the above problems, and aims to further improve the drying quality in substrate processing technology that dries substrates by utilizing the sublimation of a sublimable substance.

One aspect of the present invention is a substrate processing apparatus having a base member and a plurality of holding members provided on the surface of the base member, a substrate holding section that holds the substrate by the plurality of holding members with the substrate surface facing upward, a processing liquid supply section that supplies a processing liquid containing a sublimable substance that changes into gas without passing through a liquid state and a solvent that dissolves in the sublimable substance to the surface of the substrate held by the substrate holding section, a coagulation forming section that removes the solvent from the processing liquid on the surface of the substrate to form a coagulation containing the sublimable substance, a sublimation section that sublimes the coagulation and removes it from the surface of the substrate, and a substrate holding section that faces the surface of the substrate held by the substrate holding section. The apparatus includes an opposing member having a first opposing surface that can face the outer circumferential edge of the substrate held by the substrate holding portion and a second opposing surface that can face the outer circumferential edge of the base member, a moving section that moves the opposing member relative to the substrate holding portion, and a gas supplying section that supplies an inert gas, and during a liquid film formation period in which the processing liquid supplying section supplies the processing liquid to the surface of the substrate to form a liquid film of the processing liquid on the surface of the substrate, the moving section continues to bring the opposing member close to the substrate holding portion to form a space surrounding the substrate with the opposing member and the base member, and the gas supplying section supplies the inert gas to the space to create an inert gas-rich atmosphere in the space.

Another aspect of the present invention is a substrate processing method, which includes a liquid film forming step of supplying a processing liquid containing a sublimable substance that changes into gas without passing through a liquid state and a solvent that dissolves in the sublimable substance to the surface of a substrate held by a plurality of holding members provided on the surface of a base member to form a liquid film of the processing liquid on the surface of the substrate, a solidification forming step of removing the solvent from the liquid film on the surface of the substrate to form a solidification containing the sublimable substance, and a sublimation step of sublimating the solidification and removing it from the surface of the substrate. The liquid film forming step is characterized by having a step of facing a first opposing surface of the opposing member to the surface of the substrate held by the plurality of holding members and facing a second opposing surface of the opposing member to the outer circumferential edge of the base member to continue forming a space surrounding the substrate with the opposing member and the base member, and a step of supplying an inert gas to the space to create an inert gas-rich atmosphere in the space.

In the above invention, before a solidified body containing a sublimable substance is formed on the surface of a substrate, a treatment liquid containing the sublimable substance and a solvent that dissolves in the sublimable substance is supplied to the surface of the substrate to form a liquid film of the treatment liquid. When this liquid film formation is performed, the surface of the substrate is in contact with a space rich in inert gas. As a result, the liquid film can be formed stably, and the drying quality can be improved.

1 is a plan view showing a schematic configuration of a substrate processing system equipped with a substrate processing apparatus according to a first embodiment of the present invention; 2 is a side view of the substrate processing system shown in FIG. 1; 1 is a partial cross-sectional view showing a configuration of a processing unit corresponding to a first embodiment of a substrate processing apparatus according to the present invention; FIG. 2 is a block diagram showing an electrical configuration of a control system that controls the processing unit. 11 is a diagram showing a schematic diagram of the positional relationship between the spin base, the substrate, and the opposing member when the opposing member is located at the opposing position. FIG. FIG. 4 is a partial cross-sectional view of an opposing member and a central shaft nozzle. FIG. 2 is a schematic diagram showing the vicinity of the lower end of the central shaft nozzle as viewed from below. 4 is a flowchart showing the contents of a substrate processing performed in a processing unit. 5 is a timing chart showing operation states of a replacement process, a liquid film forming process, and a solidified body forming process in the first embodiment of the substrate processing apparatus according to the present invention. 13 is a timing chart showing operation states of a replacement process, a liquid film forming process, and a solidified body forming process in a second embodiment of the substrate processing apparatus according to the present invention. 13 is a timing chart showing operation states of a replacement process, a liquid film forming process, and a solidified body forming process in a third embodiment of the substrate processing apparatus according to the present invention.

1 is a plan view showing a schematic configuration of a substrate processing system equipped with a first embodiment of the substrate processing apparatus according to the present invention. FIG. 2 is a side view of the substrate processing system shown in FIG. 1. These drawings do not show the external appearance of the substrate processing system 100, but are schematic views showing the internal structure of the substrate processing system 100 in an easy-to-understand manner by excluding the outer wall panel and other parts of the substrate processing system 100. The substrate processing system 100 is, for example, a single-wafer type apparatus that is installed in a clean room and processes substrates W having a circuit pattern or the like (hereinafter referred to as a "pattern") formed only on one main surface. The substrate processing method according to the present invention is then executed in the processing unit 1 equipped in the substrate processing system 100. In this specification, the pattern-formed surface (one main surface) on which a pattern (see symbol PT in FIG. 6A to be described later) is formed of both main surfaces of the substrate is referred to as the "front surface", and the other main surface on the opposite side on which no pattern is formed is referred to as the "rear surface". The surface facing downward is referred to as the "lower surface", and the surface facing upward is referred to as the "upper surface". In addition, in this specification, "pattern-formed surface" refers to a surface of a substrate on which a concave-convex pattern is formed in any region.

The "substrate" in this embodiment can be any of a variety of substrates, including semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, substrates for FEDs (Field Emission Displays), substrates for optical disks, substrates for magnetic disks, and substrates for magneto-optical disks. In the following, a substrate processing apparatus used primarily for processing semiconductor wafers will be described with reference to the drawings, but the apparatus can also be used for processing the various substrates exemplified above.

1, the substrate processing system 100 includes a substrate processing section 110 that processes substrates W, and an indexer section 120 that is coupled to the substrate processing section 110. The indexer section 120 is configured to receive a container C for accommodating the substrates W (such as a FOUP (Front Opening Unified Pod) that accommodates a plurality of substrates W in a sealed state, a SMIF (Standard Insulated Fuel Container), or a FOUP (Front Opening Unified Pod) that accommodates a plurality of substrates W in a sealed state).
The indexer unit 120 has a container holding unit 121 capable of holding a plurality of containers C (e.g., Open Cassettes (OCs) and Pods (Compact Mechanical Interfaces)). The indexer unit 120 also has an indexer robot 122 for accessing the containers C held by the container holding unit 121 to take out unprocessed substrates W from the containers C and store processed substrates W in the containers C. Each container C contains a plurality of substrates W in a substantially horizontal position.

The indexer robot 122 comprises a base 122a fixed to the device housing, an articulated arm 122b rotatable about a vertical axis relative to the base 122a, and a hand 122c attached to the tip of the articulated arm 122b. The hand 122c is structured so that a substrate W can be placed on and held on its upper surface. Indexer robots having such articulated arms and hands for holding substrates are well known, so a detailed description will be omitted.

The substrate processing section 110 includes a mounting table 112 on which the indexer robot 122 places the substrate W, a substrate transport robot 111 disposed approximately in the center in a plan view, and a plurality of processing units 1 disposed to surround the substrate transport robot 111. Specifically, a plurality of processing units 1 (eight in this example) are disposed facing the space in which the substrate transport robot 111 is disposed. The substrate transport robot 111 randomly accesses the mounting table 112 for these processing units 1, and transfers the substrate W between the mounting table 112. Meanwhile, each processing unit 1 performs a predetermined process on the substrate W. In this embodiment, these processing units 1 have the same function. For this reason, parallel processing of multiple substrates W is possible. Note that the mounting table 112 is not necessarily required if the substrate transport robot 111 can directly transfer the substrate W from the indexer robot 122. As each processing unit 1, the processing units (1A to 1C) described below can be used.

Figure 3 is a partial cross-sectional view showing the configuration of a processing unit corresponding to a first embodiment of the substrate processing apparatus according to the present invention. Also, Figure 4 is a block diagram showing the electrical configuration of a control system that controls the processing units. Note that in this embodiment, a control unit 4 is provided for each processing unit 1, but multiple processing units 1 may be controlled by one control unit. Also, the processing units 1 may be controlled by a control unit (not shown) that controls the entire substrate processing system 100.

The processing unit 1 includes a chamber 20 having an internal space 21 and a spin chuck 30 accommodated in the internal space 21 of the chamber 20 to hold a substrate W. As shown in FIGS. 1 and 2, a shutter 23 is provided on the side of the chamber 20. A shutter opening/closing mechanism 22 (FIG. 4) is connected to the shutter 23, and opens and closes the shutter 23 in response to an opening/closing command from the control unit 4. More specifically, in the processing unit 1, when an unprocessed substrate W is loaded into the chamber 20, the shutter opening/closing mechanism 22 opens the shutter 23, and the unprocessed substrate W is loaded into the spin chuck 30 in a face-up position by the hand of the substrate transport robot 111. That is, the substrate W is placed on the spin chuck 30 with the front surface Wf facing upward. Then, when the hand of the substrate transport robot 111 retreats from the chamber 20 after the substrate is loaded, the shutter opening/closing mechanism 22 closes the shutter 23. Then, in the internal space 21 of the chamber 20, chemical liquids, DIW (deionized water), IPA (isopropyl alcohol) processing liquid, drying pre-processing liquid, and nitrogen gas are supplied to the surface Wf of the substrate W as described below, and the desired substrate processing is performed in a room temperature environment. After the substrate processing is completed, the shutter opening/closing mechanism 22 opens the shutter 23 again, and the hand of the substrate transport robot 111 removes the processed substrate W from the spin chuck 30. Thus, in this embodiment, the internal space 21 of the chamber 20 functions as a processing space for performing substrate processing while maintaining a room temperature environment. In this specification, "room temperature" means a temperature range of 5°C to 35°C.

The spin chuck 30 has multiple chuck pins 31. In the spin chuck 30, the multiple chuck pins 31 are provided on the peripheral portion of the upper surface of the disk-shaped spin base 32. In this embodiment, the chuck pins 31 are arranged at appropriate intervals (e.g., equal intervals) around the circumference of the spin base 32 and grip the peripheral portion of the substrate W. In this way, the substrate W is held by the spin chuck 30.

A rotating shaft 33 is connected to the spin base 32. This rotating shaft 33 is provided so as to be rotatable about a rotation axis AX1 parallel to a surface normal extending from the center of the surface of the substrate W supported by the spin chuck 30. The rotating shaft 33 is connected to a substrate rotation drive mechanism 34 including a motor and the like. Therefore, when the motor of the substrate rotation drive mechanism 34 operates in response to a rotation command from the control unit 4 while the substrate W placed on the spin chuck 30 is held by the chuck pins 31, the substrate W rotates about the rotation axis AX1 at a rotation speed corresponding to the rotation command. In addition, while the substrate W is rotated in this manner, a chemical solution, an IPA processing solution, DIW, a drying pretreatment solution, and nitrogen gas are supplied to the surface Wf of the substrate W from the central axis nozzle 60 that vertically passes through the opposing member 50 in response to a supply command from the control unit 4.

Figure 5 is a schematic diagram showing the positional relationship between the spin base, the substrate, and the opposing member when the opposing member is located at the opposing position. As shown in Figures 3 and 5, the opposing member 50 is a driven opposing member that rotates following the spin chuck 30. That is, the opposing member 50 is supported by the spin chuck 30 so that it can rotate integrally with the spin chuck 30 during substrate processing. To make this possible, the opposing member 50 has an opposing plate 51, an engaging member 52 that is provided on the opposing plate 51 so that it can rise and fall together with the opposing plate 51, and a support portion 53 that engages with the engaging member 52 to support the opposing plate 51 from above.

The opposing plate 51 is disk-shaped and has a diameter larger than the diameter of the substrate W, and has a cap shape that covers the substrate W from above vertically. More specifically, the opposing plate 51 has a disk portion 511 held in a horizontal position, and a cylindrical portion 512 that extends downward from the outer periphery of the disk portion 511. The inner surface 513 of the opposing plate 51 is a cup surface that is concave downward. The inner surface 513 has a substrate-facing surface 513a, a central inclined surface 513b, and an inner circumferential surface 513c.

The substrate facing surface 513a corresponds to the lower surface of the disk portion 511. More specifically, the substrate facing surface 513a is finished into a flat surface parallel to the upper surface of the substrate W and faces the front surface Wf of the substrate W.

The central inclined surface 513b also has an inclined surface surrounded by the substrate facing surface 513a. More specifically, the central inclined surface 513b has an annular central inclined portion that extends obliquely upward from the substrate facing surface 513a toward the rotation axis AX1, and has the following characteristics: The central inclined portion has a gentle slope with a constant inclination angle relative to the rotation axis AX1. The cross section of the central inclined portion opens downward. The inner diameter of the central inclined surface 513b increases as it approaches the lower end of the central inclined surface 513b. The lower end of the central inclined surface 513b is connected to the substrate facing surface 513a. Therefore, when the opposing member 50 is in the opposing position, the lower end of the central axis nozzle 60 is exposed downward while being surrounded by the central inclined surface 513b (see Figures 6A and 6B described later).

Furthermore, the inner peripheral surface 513c corresponds to the inner surface of the cylindrical portion 512. More specifically, the inner peripheral surface 513c has an annular inner inclined portion that extends obliquely downward and outward from the substrate facing surface 513a, and has the following characteristics. The inner inclined portion has an arc-shaped cross section in which the inclination angle with respect to the rotation axis AX1 changes continuously. The cross section of the inner inclined portion opens downward. The inner diameter of the inner peripheral surface 513c increases as it approaches the lower end of the inner peripheral surface 513c. The lower end of the inner peripheral surface 513c has an inner diameter larger than the outer diameter of the spin base 32. Therefore, as shown by the dashed line in FIG. 3, when the facing member 50 is in the facing position, it faces the outer peripheral end of the substrate W and the outer peripheral surface (outer peripheral end) 32b of the spin base 32.

The opposing plate 51 further has a plurality of second engaging members 514 provided on the substrate opposing surface 513a for engaging with the first engaging member 35. A through hole 515 that penetrates the opposing member 50 vertically is formed in the center of the substrate opposing surface 513a. The through hole 515 is defined by a cylindrical inner circumferential surface. The second engaging members 514 are provided in the same number as the first engaging members 35 and in one-to-one correspondence with the first engaging members 35. The configurations of the first engaging members 35 and the second engaging members 514 are conventionally known. For example, the configuration described in JP 2019-57599 A can be used as the engaging members 35 and 514 of this embodiment. When the first engaging member 35 and the second engaging member 514 engage with each other, the opposing member 50 is supported by the spin base 32 via the engaging body. When the spin base 32 rotates due to the operation of the motor, the opposing member 50 rotates integrally with it around the rotation axis AX1.

As shown in FIG. 3, the engagement member 52 has a cylindrical portion 521 that surrounds the through hole 515 on the upper surface of the opposing plate 51, and a flange portion 522 that extends radially outward from the upper end of the cylindrical portion 521. The flange portion 522 is located above the flange support portion 531, which is a component of the support portion 53, and the outer periphery of the flange portion 522 is larger in diameter than the inner periphery of the flange support portion 531.

The support portion 53 has a horizontal flange support portion 531, a substantially disk-shaped support portion main body 532, and a connection portion 533 that connects the flange support portion 531 and the support portion main body 532. The central axis nozzle 60 extends vertically along a vertical axis passing through the center of the opposing plate 51 and the substrate W, i.e., along the rotation axis AX1, so as to pass through the internal space of the support portion 53 and the opposing plate 51. The central axis nozzle 60 is raised and lowered together with the support portion 53 by the opposing plate raising and lowering drive mechanism 56. For example, as shown by the solid line in FIG. 3, when the central axis nozzle 60 and the opposing member 50 are positioned at a retracted position vertically above the substrate W, the tip of the central axis nozzle 60 is spaced upward from the surface Wf of the substrate W held by the spin chuck 30. Then, in response to a lowering command from the control unit 4, the opposing plate lifting drive mechanism 56 lowers the central axis nozzle 60 and the support part 53 downward, and positions the opposing member 50 at the opposing position as shown by the dashed line in FIG. 3 and FIG. 5. This brings the opposing plate 51 of the opposing member 50 close to the front surface Wf of the substrate W. As a result, a semi-closed space SP is formed by the substrate facing surface (first opposing surface) 513a, the inner peripheral surface (second opposing surface) 513c, and the outer peripheral surface (outer peripheral end) 32b of the spin base 32, surrounding the substrate W held by the spin chuck 30. Then, while the substrate W is enclosed in the semi-closed space SP and isolated from the surrounding atmosphere, as shown in FIG. 6A and FIG. 6B, the chemical liquid, IPA processing liquid, DIW, pre-drying processing liquid, and nitrogen gas are supplied to the front surface Wf of the substrate W from the central axis nozzle 60.

Figure 6A is a partial cross-sectional view of the opposing member and the central shaft nozzle. Figure 6B is a schematic diagram of the vicinity of the lower end of the central shaft nozzle viewed from below. The dotted line area in Figure 6A is a partial enlarged view of the front surface Wf of the substrate W, and an example of a pattern PT formed on the front surface Wf is shown. The central shaft nozzle 60 has a nozzle body 61 that extends in the vertical direction along the rotation axis AX1. Five central pipe sections (not shown) are provided in the center of the nozzle body 61, penetrating from the upper end surface to the lower end surface of the nozzle body 61. The lower end surface openings of these five central pipe sections function as a chemical liquid outlet 62a, a DIW outlet 63a, an IPA outlet 64a, a pre-drying treatment liquid outlet 65a, and a central gas outlet 66a, respectively.

As shown in FIG. 3, the central piping section having the chemical solution outlet 62a is connected to a chemical solution supply section (not shown) via a piping 62b. A valve 62c is interposed in this piping 62b. Therefore, when the valve 62c is opened in response to an opening/closing command from the control section 4, the chemical solution is supplied to the central axis nozzle 60 via the piping 62b and is discharged from the chemical solution outlet 62a toward the center of the surface of the substrate W. In this embodiment, the chemical solution only needs to have a function of cleaning the surface Wf of the substrate W, and may be, for example, a liquid containing at least one of sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid, ammonia water, hydrogen peroxide, organic acid (e.g., citric acid, oxalic acid, etc.), organic alkali (e.g., TMAH: tetramethylammonium hydroxide, etc.), surfactant, and corrosion inhibitor, or may be other liquids.

As shown in FIG. 3, the central piping section having the DIW outlet 63a is connected to a DIW supply section (not shown) via a piping 63b. A valve 63c is interposed in this piping 63b. Therefore, when the valve 63c is opened in response to an opening/closing command from the control section 4, the IPA processing liquid is supplied to the central axis nozzle 60 via the piping 63b and is discharged from the DIW outlet 63a toward the center of the surface of the substrate W. In this embodiment, as described later, DIW is used as a rinsing liquid for rinsing the surface Wf of the substrate W after chemical processing, but other rinsing liquids may be used. For example, any of carbonated water, electrolytic ion water, hydrogen water, ozone water, and hydrochloric acid water with a diluted concentration (for example, about 10 to 100 ppm) may be used as the rinsing liquid.

As shown in FIG. 3, the central piping section having the IPA outlet 64a is connected to an IPA processing liquid supply section (not shown) via a piping 64b. A valve 64c is interposed in this piping 64b. Therefore, when the valve 64c is opened in response to an opening/closing command from the control section 4, the IPA processing liquid is supplied to the central axis nozzle 60 via the piping 64b and is discharged from the IPA outlet 64a toward the center of the surface of the substrate W. In this embodiment, the IPA processing liquid is used as a replacement liquid for replacing the rinsing liquid (DIW) adhering to the surface Wf of the substrate W after the rinsing process, but other liquids may be used. More specifically, a liquid that dissolves in both the rinsing liquid and the drying pretreatment liquid may be used as the replacement liquid. For example, it may be HFE (hydrofluoroether) or a mixture of IPA and HFE, or it may contain at least one of IPA and HFE and other components.

As shown in FIG. 3, the central piping section having the pre-drying treatment liquid outlet 65a is connected to the pre-drying treatment liquid supply section (not shown) via a piping 65b. A valve 65c is interposed in this piping 65b. Therefore, when the valve 65c is opened in response to an opening/closing command from the control section 4, the pre-drying treatment liquid is supplied to the central axis nozzle 60 via the piping 65b and is discharged from the pre-drying treatment liquid outlet 65a toward the center of the surface of the substrate W. In this embodiment, a solution containing a sublimable substance corresponding to a solute and a solvent that dissolves in the sublimable substance is used as the pre-drying treatment liquid. Here, the sublimable substance may be a substance that changes from a solid to a gas without passing through a liquid at room temperature (synonymous with room temperature) or normal pressure (pressure inside the processing unit 1, for example, 1 atmosphere or a value therearound). The solvent may be such a substance or a substance other than the above. In other words, the pre-drying treatment liquid may contain two or more types of substances that change from a solid to a gas without passing through a liquid at room temperature or normal pressure.

The sublimable substance may be, for example, any of the following: alcohols such as 2-methyl-2-propanol (also known as tert-butyl alcohol, t-butyl alcohol, or tertiary butyl alcohol) or cyclohexanol; fluorohydrocarbon compounds; 1,3,5-trioxane (also known as metaformaldehyde); camphor (also known as camphor); naphthalene; iodine; cyclohexanone oxime; and cyclohexane; or any other substance.

The solvent may be, for example, at least one selected from the group consisting of pure water, IPA, HFE, acetone, PGMEA (propylene glycol monomethyl ether acetate), PGEE (propylene glycol monoethyl ether, 1-ethoxy-2-propanol), ethylene glycol, and hydrofluorocarbon.

The central piping section having the central gas outlet 66a is connected to a nitrogen gas supply section (not shown) via piping 66b, as shown in FIG. 3. A valve 66c is interposed in this piping 66b. Therefore, when the valve 66c is opened in response to an opening/closing command from the control section 4, nitrogen gas is supplied to the central axis nozzle 60 via piping 66b, and is discharged from the central gas outlet 66a toward the center of the surface of the substrate W, as shown by the dashed arrow in FIG. 6A.

The lower end surface 61a on which the five discharge ports 62a to 66a are thus provided is recessed above the substrate-facing surface 513a and the central inclined surface 513b in the unblocked state, as shown by the solid lines in Figure 3. On the other hand, in the blocked state, as shown in Figures 6A and 6B, the lower end surface 61a is positioned at the same height as the substrate-facing surface 513a in the vertical direction, and the lower end portion 61b of the nozzle body 61 is exposed downward from the through-hole 515 while being surrounded by the central inclined surface 513b.

On the side of the lower end 61b, six peripheral gas outlets 67 are provided at approximately equal angular intervals around the rotation axis AX1. As shown in FIG. 6A, peripheral piping 68 extending from the side of the nozzle body 61 to the upper end surface of the nozzle body 61 is connected to these peripheral gas outlets 67. As shown in FIG. 3, the peripheral piping 68 is connected to a nitrogen gas supply unit (not shown) via piping 68b. A valve 68c is interposed in this piping 68b. Therefore, when the valve 68c is opened in response to an opening/closing command from the control unit 4, nitrogen gas is supplied to the central axis nozzle 60 via the piping 68b and is discharged from the peripheral gas outlets 67 in an approximately horizontal direction around the rotation axis AX1. The nitrogen gas discharged approximately horizontally is guided toward the surface peripheral portion of the substrate W along the central inclined surface 513b and the substrate facing surface 513a, as shown by the dotted arrow in FIG. 6A.

As described above, in this embodiment, as shown in FIG. 6A, the nitrogen gas is supplied to the substrate W in the following manner:
A first supply mode (a dashed-dotted arrow in the figure) in which the liquid is supplied to the peripheral portion of the surface of the substrate W via the central portion of the surface of the substrate W;
A second supply mode (dotted arrow in the figure) in which the gas is supplied to the peripheral portion of the surface of the substrate W without passing through the central portion of the surface of the substrate W;
There are. The control unit 4 controls the opening and closing of the valves 66c and 68c, and selectively switches between a mode in which the supply of nitrogen gas is stopped, a mode in which only the first supply mode is executed, a mode in which only the second supply mode is executed, and a mode in which the first supply mode and the second supply mode are executed simultaneously. Although not shown in the figure, the flow rates of the nitrogen gas supplied in the first supply mode and the second supply mode can be independently variably controlled in response to a command from the control unit 4. In this embodiment, nitrogen gas is used as the "inert gas" of the present invention, but other inert gases such as dehumidified argon gas may be used.

In addition, in the processing unit 1, an exhaust bucket 70 is provided to surround the spin chuck 30. Also provided are a number of cups 72 arranged between the spin chuck 30 and the exhaust bucket 70, and a number of guards 73 for receiving the chemical liquid, rinsing liquid (DIW), IPA processing liquid, and pre-drying processing liquid that have splashed around the substrate W. Also, a guard lifting drive mechanism 71 is connected to the guard 73. The guard lifting drive mechanism 71 independently lifts and lowers the guard 73 in response to a lifting command from the control unit 4. Furthermore, an exhaust mechanism 74 is connected to the exhaust bucket 70. This exhaust mechanism 74 exhausts the space surrounded by the inner bottom surface of the chamber 20, the exhaust bucket 70, and the guard 73.

The control unit 4 has an arithmetic unit such as a CPU, a storage unit such as a fixed memory device and a hard disk drive, and an input/output unit. The storage unit stores a program executed by the arithmetic unit. The control unit 4 controls each part of the device according to the program, thereby executing the substrate processing shown in FIG. 7.

Figure 7 is a flowchart showing the contents of the substrate processing performed in the processing unit. The processing object in the substrate processing system 100 is, for example, a silicon wafer, and an uneven pattern PT (see Figure 6A) is formed on the surface Wf, which is the pattern formation surface. The pattern PT may be a logic circuit, a dynamic random access memory (DRAM), or a phase-change random access memory (PRAM) that utilizes the unique properties of a chalcogenide alloy. The pattern PT may be a repeated line pattern formed by fine trenches. The pattern PT may also be formed by providing a thin film with multiple fine holes (voids or pores). The pattern PT includes, for example, an insulating film. The pattern PT may also include a conductive film. More specifically, the pattern PT is formed by a laminated film in which multiple films are laminated, and may further include an insulating film and a conductive film. The pattern PT may be a pattern PT composed of a single layer film. The insulating film may be a silicon oxide film or a silicon nitride film. The conductor film may be an amorphous silicon film with impurities introduced to reduce resistance, or a metal film (e.g., a TiN film). The pattern PT may be formed at the front end or at the back end. The pattern PT may be a hydrophobic film or a hydrophilic film. Examples of hydrophilic films include a TEOS film (a type of silicon oxide film).

Unless otherwise specified, each process shown in FIG. 7 is performed in an atmospheric pressure environment. Here, atmospheric pressure environment refers to an environment of 0.7 atmospheres or more and 1.3 atmospheres or less, with the standard atmospheric pressure (1 atmosphere, 1013 hPa) at the center. In particular, when the substrate processing system 100 is placed in a clean room with positive pressure, the environment of the surface Wf of the substrate W will be higher than 1 atmosphere.

Before an unprocessed substrate W is loaded into the processing unit 1, the control unit 4 issues commands to each part of the apparatus and the processing unit 1 is set to its initial state. That is, the shutter 23 (FIGS. 1 to 3) is closed by the shutter opening/closing mechanism 22. The spin chuck 30 is positioned and stopped at a position suitable for loading the substrate W by the substrate rotation drive mechanism 34, and the chuck pins 31 are in an open state by a chuck opening/closing mechanism (not shown). The opposing plate 51 is positioned at a retracted position by the opposing plate lift drive mechanism 56. As a result, support of the opposing plate 51 by the spin base 32 is released, and the rotation of the opposing plate 51 is stopped. All of the guards 73 have been moved downward and positioned. Furthermore, all of the valves 62c to 66c and 68c are closed.

When an unprocessed substrate W is transported by the substrate transport robot 111, the shutter 23 opens. As the shutter 23 opens, the substrate W is transported by the substrate transport robot 111 into the internal space 21 of the chamber 20, and is transferred to the spin chuck 30 in a face-up state with the front surface Wf facing upward. The chuck pins 31 are then closed, and the substrate W is held by the spin chuck 30 (step S1: Substrate Transport).

After the substrate W is loaded, the substrate transport robot 111 retreats to the outside of the chamber 20, and the shutter 23 closes again. After that, the control unit 4 controls the opposing plate lifting drive mechanism 56 to place the opposing plate 51 in the opposing position. As a result, as shown in FIG. 5, the engagement member 514 provided on the opposing plate 51 is received by the engagement member 35, and the opposing plate 51 and the central axis nozzle 60 are supported by the spin base 32. In addition, the opposing plate 51 and the spin base 32 are close to each other to form a semi-closed space SP. As a result, the substrate W held by the spin chuck 30 is confined in the space SP and is isolated from the surrounding atmosphere. In this embodiment, the opposing plate 51 is positioned in the opposing position until the sublimation process (step S8) described later is completed.

Following completion of confinement of the substrate W in the space SP, the control unit 4 controls the motor (not shown) of the substrate rotation drive mechanism 34 to increase the rotation speed of the spin base 32 to a predetermined chemical processing speed (within a range of approximately 10 to 1200 rpm, for example, approximately 800 rpm) and maintains the speed at the chemical processing speed. Accompanying this rotation of the spin base 32, the opposing plate 51 rotates about the rotation axis AX1, and the substrate W rotates about the rotation axis AX1 (step S2: substrate rotation starts). Note that before proceeding to the next chemical processing, the control unit 4 raises the guard 73 corresponding to the chemical processing, so that the guard 73 faces the gap GP between the inner circumferential surface 513c of the opposing plate 51 and the outer circumferential surface 32b of the spin base 32.

When the rotation speed of the substrate W reaches the chemical processing speed, the control unit 4 then opens the valve 62c. This causes the chemical to be discharged from the chemical outlet 62a of the central axis nozzle 60 and supplied to the front surface Wf of the substrate W. On the front surface Wf of the substrate W, the chemical moves to the periphery of the substrate W due to the centrifugal force caused by the rotation of the substrate W. As a result, the entire front surface Wf of the substrate W is subjected to chemical cleaning with the chemical (step S3). At this time, the chemical that has reached the periphery of the substrate W is discharged from the periphery of the substrate W to the side of the substrate W and is sent to the waste liquid processing equipment outside the machine via the guard 73. This chemical cleaning by supplying the chemical continues for a predetermined cleaning time, and when that time has elapsed, the control unit 4 closes the valve 62c to stop the discharge of the chemical from the central axis nozzle 60.

Following the chemical cleaning, a rinse process using a rinse liquid (DIW) is performed (step S4). In this DIW rinse, the control unit 4 opens the valve 63c. As a result, DIW is supplied as a rinse liquid from the DIW outlet 63a of the central axis nozzle 60 to the center of the surface Wf of the substrate W that has been subjected to the chemical cleaning process. Then, the DIW moves to the peripheral portion of the substrate W due to the centrifugal force caused by the rotation of the substrate W. As a result, the chemical liquid adhering to the substrate W is washed away by the DIW. At this time, the DIW discharged from the peripheral portion of the substrate W is discharged from the peripheral portion of the substrate W to the side of the substrate W and is sent to the waste liquid treatment equipment outside the machine in the same manner as the chemical liquid. This DIW rinse continues for a predetermined rinse time, and when that time has elapsed, the control unit 4 closes the valve 63c to stop the discharge of DIW from the central axis nozzle 60.

After the DIW rinse is completed, the replacement process (step S5), the liquid film formation process (step S6), and the solidification process (step S7) are carried out.

8 is a timing chart showing the operation status of the replacement process, the liquid film formation process, and the solidification body formation process in the first embodiment of the substrate processing apparatus according to the present invention. The "vertical N2 flow rate" in the figure means the flow rate of nitrogen gas discharged downward from the central gas outlet 66a. In other words, the control unit 4 opens the valve 66c, so that nitrogen gas is supplied from the central gas outlet 66a to the center of the surface Wf of the substrate W. This nitrogen gas is supplied to the entire substrate W along the surface Wf of the substrate W (first supply mode: see the dashed line in FIG. 6A). The flow rate of nitrogen gas supplied via the surface center in this way is the "vertical N2 flow rate". On the other hand, the "horizontal N2 flow rate" in the figure means the flow rate of nitrogen gas discharged from the six peripheral gas outlets 67 in a substantially horizontal direction. In other words, the control unit 4 opens the valve 68c, so that nitrogen gas is discharged radially around the rotation axis AX1. This nitrogen gas is supplied to the peripheral portion of the surface of the substrate W along the central inclined surface 513b and the substrate-facing surface 513a (second supply mode: see dotted line in FIG. 6A). The flow rate of nitrogen gas supplied to the peripheral portion of the surface in this manner without passing through the central portion of the surface is the "horizontal N2 flow rate."

In the replacement process (step S5), the control unit 4 controls the motor (not shown) of the substrate rotation drive mechanism 34 to adjust the rotation speed of the substrate W to a predetermined first rotation speed V1 and maintain the first rotation speed V1. The control unit 4 also adjusts the flow rates of the nitrogen gas from the central gas outlet 66a and the peripheral gas outlet 67 to "VF1" and "HF1", respectively. This allows nitrogen gas to be supplied to the semi-closed space SP, making the space SP nitrogen-rich. In addition, it is possible to effectively prevent outside air from entering the space SP from the surrounding atmosphere through the gap GP (see FIG. 5), which is the only part that connects the space SP to the surrounding atmosphere. This makes the space SP a low-oxygen environment. Here, "low oxygen" refers to an oxygen concentration of 100 ppm or less.

The control unit 4 also faces the gap GP with the guard 73 corresponding to the replacement process. Then, the control unit 4 opens the valve 64c. As a result, the IPA treatment liquid is discharged as a low surface tension liquid from the IPA discharge port 64a of the central axis nozzle 60 toward the center of the surface Wf of the substrate W to which the DIW is attached. The IPA treatment liquid supplied to the surface Wf of the substrate W spreads over the entire surface Wf of the substrate W due to the centrifugal force caused by the rotation of the substrate W. As a result, the DIW (rinsing liquid) attached to the surface Wf of the substrate W is replaced by the IPA treatment liquid over the entire surface Wf of the substrate W. The IPA treatment liquid moving on the surface Wf of the substrate W is discharged from the periphery of the substrate W to the side of the substrate W, received by the guard 73, and sent to the recovery equipment along a recovery path not shown. This IPA replacement continues for a predetermined replacement time, and after that time has elapsed, the control unit 4 closes the valve 64c to stop the discharge of the IPA treatment liquid from the central axis nozzle 60.

After the IPA replacement, a liquid film formation process (step S6) is performed. This liquid film formation process includes a pre-drying treatment liquid supply process (step S6a) for supplying a pre-drying treatment liquid, a spin-off process (step S6b), and a sublimable material settling process (step S6c) for allowing the sublimable material contained in the pre-drying treatment liquid to settle between the patterns PT. These steps S6a to S6c are performed in this order.

In the pre-drying treatment liquid supply step (step S6a), the control unit 4 maintains the rotation speed of the substrate W, the vertical N2 flow rate, and the horizontal N2 flow rate at the values "V1", "VF1", and "HF1" in the replacement process, respectively, as shown in FIG. 8. The control unit 4 makes the guard 73 corresponding to the pre-drying treatment liquid supply step face the gap GP. The control unit 4 opens the valve 65c. As a result, the pre-drying treatment liquid is discharged from the pre-drying treatment liquid discharge port 65a of the central axis nozzle 60 toward the center of the front surface Wf of the substrate W to which the replacement liquid is attached. The pre-drying treatment liquid supplied to the front surface Wf of the substrate W spreads over the entire front surface Wf of the substrate W due to the centrifugal force caused by the rotation of the substrate W. As a result, the IPA treatment liquid is replaced with the pre-drying treatment liquid over the entire front surface Wf of the substrate W, and a relatively thick liquid film of the pre-drying treatment liquid is formed. The ejection of the pre-drying treatment liquid continues for a predetermined time, after which the control unit 4 closes the valve 65c to stop the ejection of the pre-drying treatment liquid from the central shaft nozzle 60.

In the spin-off process (step S6b), the control unit 4 closes the valves 66c and 68c to stop the discharge of nitrogen gas, and controls the motor (not shown) of the substrate rotation drive mechanism 34 to increase the rotation speed of the substrate W to a spin-off speed V3 that is higher than the first rotation speed V1. The control unit 4 then maintains the spin-off speed V3 for a predetermined time. This removes excess pre-drying treatment liquid from the surface Wf of the substrate W, and adjusts the thickness of the liquid film of the pre-drying treatment liquid to the desired thickness.

In the sublimable substance sinking process (step S6c), the control unit 4 stops the discharge of nitrogen gas and controls the motor of the substrate rotation drive mechanism 34 to decelerate the rotation speed of the substrate W to a second rotation speed V2 lower than the first rotation speed V1. Then, the control unit 4 waits for a predetermined time to elapse. During this waiting time, the sublimable substance present in the liquid film of the pre-drying treatment liquid sinks and fills the spaces between the patterns PT. In addition, in the latter half of the predetermined time, the control unit 4 opens the valve 66c. This causes nitrogen gas to be discharged to the center of the surface of the substrate W. Thus, in this embodiment, in the latter half of the sublimable substance sinking process, nitrogen gas is vertically discharged from the central gas discharge port 66a at a flow rate VF1 in the first supply mode. Therefore, the following action and effect are obtained. By performing the above nitrogen gas control before the coagulation formation process (step S7) described later, the solvent of the pre-drying treatment liquid near the center of the surface Wf of the substrate W can be evaporated to increase the solute concentration. Furthermore, by ejecting nitrogen gas horizontally in the subsequent solidification formation process (step S7), the solute concentration on the surface Wf of the substrate W can be made uniform. This makes it possible to make the film thickness of the solidification uniform.

When a liquid film of the pre-drying liquid suitable for sublimation drying is formed on the surface Wf of the substrate W in this way, the coagulation formation process (step S7) is performed. The control unit 4 controls the motor of the substrate rotation drive mechanism 34 to increase the rotation speed of the substrate W from the first rotation speed V1. More specifically, the control unit 4 increases the speed to the spin-off speed V3 and increases the flow rate of the nitrogen gas. More specifically, the flow rate of the nitrogen gas discharged from the central gas discharge port 66a is increased from flow rate VF1 to flow rate VF2, and the valve 68c is opened to discharge the nitrogen gas from the peripheral gas discharge port 67. During the lapse of a predetermined time from the increase in the rotation speed and the nitrogen gas, the solvent in the liquid film is removed and a coagulation of the sublimable material is formed.

Following the formation of such a solidified body, the control unit 4 further increases the rotation speed to V4 (> V3) and maintains the rotation speed V4. The control unit 4 also maintains the flow rate of the nitrogen gas discharged from the central gas outlet 66a at flow rate VF2, opens the valve 68c, raises the flow rate of the nitrogen gas discharged from the peripheral gas outlet 67 from flow rate HF2 to flow rate HF3, and increases the flow rate of the nitrogen gas flowing along the surface Wf of the substrate W, thereby performing the sublimation process (step S8).

The sublimation process may be performed at the same final speed and flow rate as in the solidification process, but in this embodiment, the rotation speed and flow rate are stepped up. This increases the sublimation speed, preventing pattern collapse during sublimation and shortening the drying time. Then, when a predetermined time has elapsed since the step-up, the control unit 4 stops the motor of the substrate rotation drive mechanism 34 to stop the rotation of the substrate W (step S9: Stop substrate rotation).

Then, the control unit 4 controls the opposing plate lifting drive mechanism 56 to raise the opposing plate 51 from the opposing position and position it in the retracted position. Furthermore, the control unit 4 retracts all of the guards 73 downward from the gap GP.

Then, the control unit 4 controls the shutter opening/closing mechanism 22 to open the shutter 23 (FIGS. 1 to 3), and then the substrate transport robot 111 enters the internal space of the chamber 20 and transports the processed substrate W, which has been released from the chuck pins 31, out of the chamber 20 (step S10). When the substrate W has been removed and the substrate transport robot 111 has left the processing unit 1, the control unit 4 controls the shutter opening/closing mechanism 22 to close the shutter 23.

As described above, in the first embodiment, during the liquid film formation process (step S6), the opposing plate 51 and the spin base 32 are close to each other to form a semi-closed space SP, and the space SP is made to have a nitrogen gas-rich atmosphere. Then, the liquid film of the pre-drying treatment liquid is formed in a state where the surface Wf of the substrate W is in contact with the inert gas-rich space SP. This allows the liquid film to be formed stably. For example, when a substrate W having a pattern PT for constituting a logic circuit, DRAM, or PRAM formed on its surface Wf is dried by the conventional technology, a problem may occur in which a part of the pattern PT, especially the line width portion, is oxidized. In contrast, according to the present embodiment, the liquid film of the pre-drying treatment liquid is formed in the nitrogen gas-rich space SP. That is, the liquid film is formed in a low-oxygen state. As a result, the above problem can be effectively suppressed.

In addition, in the first embodiment, nitrogen gas is discharged from both the central gas outlet 66a and the peripheral gas outlet 67 in the pre-drying treatment liquid supply process (step S6a). This allows the space SP to be filled with a nitrogen gas-rich atmosphere from the beginning of the liquid film formation period, making it possible to more stably form the liquid film. Here, it is not essential to discharge the nitrogen gas from both outlets 66a, 67 simultaneously, and the timing of the nitrogen gas discharge may be shifted from each other, or the nitrogen gas may be discharged from only one of the outlets.

As described above, in the first embodiment, the chuck pin 31 and the spin base 32 correspond to an example of the "base member" and "holding member" of the present invention, respectively, and the spin chuck 30 equipped with these corresponds to an example of the "substrate holding section" of the present invention. The drying pretreatment liquid and the nitrogen gas correspond to an example of the "treatment liquid" and "inert gas" of the present invention, respectively. The central axis nozzle 60 that discharges the drying pretreatment liquid and the nitrogen gas functions as the "treatment liquid supply section", the "gas supply section", the "solidified body forming section" and the "sublimation section" of the present invention. The central gas outlet 66a and the peripheral gas outlet 67 provided in the central axis nozzle 60 correspond to an example of the "first gas outlet" and the "second gas outlet" of the present invention, respectively. The valves 66c and 68c correspond to an example of the "first gas outlet" and the "second gas outlet" of the present invention, respectively. The opposing plate lifting and lowering drive mechanism 56 corresponds to an example of the "moving section" of the present invention. The substrate rotation drive mechanism 34 corresponds to an example of the "rotating section" of the present invention. The execution period of step S6 corresponds to an example of the "liquid film formation period" of the present invention. Among them, steps S6a and S6c correspond to an example of the "initial stage of the liquid film formation period" and the "final stage of the liquid film formation period" of the present invention, respectively. The execution period of step S6c corresponds to an example of the "sublimable material sinking period" of the present invention. During the sublimable material sinking period (step S6c), the period during which the flow rate of vertical N2 is maintained at zero corresponds to an example of the "first half of the sublimable material sinking period" of the present invention, and the period during which the flow rate of vertical N2 is maintained at the value "VF1" corresponds to an example of the "second half of the sublimable material sinking period" of the present invention.

Figure 9 is a timing chart showing the operating conditions of the replacement process, the liquid film forming process, and the solidified body forming process in a second embodiment of the substrate processing apparatus according to the present invention. The second embodiment differs significantly from the first embodiment in the manner in which nitrogen gas is supplied in the liquid film forming process (step S6) and the solidified body forming process (step S7). The rest of the configuration and operation are basically the same as in the first embodiment, so the differences will be mainly described here, and the same or corresponding reference symbols will be used and explanations will be omitted.

In the second embodiment, as shown in FIG. 9, the discharge of nitrogen gas from the peripheral gas outlet 67 continues from the drying pretreatment liquid supply process (step S6a) and continues in the spin-off process (step S6b) and sublimable material settling process (step S6c). On the other hand, the discharge of nitrogen gas from the central gas outlet 66a is stopped simultaneously with the completion of the drying pretreatment liquid supply process (step S6a), and the discharge stop state continues in the spin-off process (step S6b) and sublimable material settling process (step S6c). Thus, in the second embodiment, nitrogen gas is supplied to the space SP in the liquid film formation process (step S6), ensuring that the low-oxygen state is maintained.

In the solidification formation process (step S7), the flow rate of nitrogen gas discharged from the peripheral gas outlets 67 is increased from value HF1 to value HF2, while the flow rate of nitrogen gas discharged from the central gas outlets 66a is maintained at zero. In other words, nitrogen gas is not supplied to the central portion of the surface of the substrate W, but is supplied to the peripheral portion of the surface of the substrate W along the central inclined surface 513b and the substrate facing surface 513a of the facing plate 51.

When a certain period of time has passed and a coagulation has been formed, the control unit 4 opens the valve 66c and starts supplying nitrogen gas from the central gas outlet 66a to the center of the surface of the substrate W (discharge flow rate VF2). In synchronization with this, the discharge flow rate of nitrogen gas from the peripheral gas outlets 67 is increased from value HF2 to value HF3. In this way, as shown in FIG. 6A, a large amount of nitrogen gas is supplied to the entire surface Wf of the substrate W, and the coagulation is efficiently sublimated (step S8).

As described above, according to the second embodiment, not only the same effect as in the first embodiment can be obtained, but also the effect described below. In this embodiment, there are two nitrogen gas supply modes, and as in the first embodiment, the supply to the center of the surface of the substrate W may be given priority. In this case, gas components are generated from the center of the surface before the peripheral portion of the surface, and flow to the peripheral portion of the surface. Since the space SP of this device is in a semi-closed state, the gas components tend to stagnate at the peripheral portion of the surface. Therefore, the subsequent process cannot be performed favorably, and there is a possibility that the pattern collapse occurs at the peripheral portion of the surface. In contrast, in the second embodiment, since the nitrogen gas is supplied to the peripheral portion of the surface before the central portion of the surface, the pattern collapse at the peripheral portion of the surface can be effectively prevented. Moreover, since the flow rate of the nitrogen gas supplied to the peripheral portion of the surface is increased at the same time as the supply of the nitrogen gas to the central portion of the surface is started, the gas components generated from the surface Wf of the substrate W can be reliably discharged from the gap GP. As a result, the substrate W can be dried well.

In the second embodiment, the execution period of the coagulation formation process (step S7) corresponds to an example of the "coagulation formation period" of the present invention. Also, the timing of switching from the coagulation formation process to the sublimation process corresponds to an example of "after the coagulation formation period has elapsed" of the present invention.

Figure 10 is a timing chart showing the operating conditions of the replacement process, the liquid film formation process, and the solidification process in a third embodiment of a substrate processing apparatus according to the present invention. The third embodiment differs significantly from the second embodiment in the supply of nitrogen gas in the latter half of the sublimable material sinking process (step S6c) and the change in the flow rate of nitrogen gas from the peripheral gas outlet 67 in the solidification process (step S7) and the sublimation process (step S8). The rest of the configuration and operation are basically the same as in the second embodiment, so the differences will be mainly described here, and the same or corresponding symbols will be used and explanations will be omitted.

In the second embodiment (FIG. 9), nitrogen gas is supplied from the peripheral gas outlet 67 in the latter half of the sublimable material sinking process (step S6c). In contrast, in the third embodiment, as shown in FIG. 10, the discharge of nitrogen gas from the peripheral gas outlet 67 is temporarily stopped and nitrogen gas is discharged from the central gas outlet 66a to the center of the surface of the substrate W only during the period corresponding to the latter half. In this way, the nitrogen gas may be temporarily changed from the second supply mode (see dotted line in FIG. 6A) to the first supply mode (see dashed line in FIG. 6A). In addition, nitrogen gas may be discharged from the central gas outlet 66a to the center of the surface of the substrate W while maintaining the discharge of nitrogen gas from the peripheral gas outlet 67.

In the second embodiment (FIG. 9), the flow rate of nitrogen gas discharged from the peripheral gas outlet 67 is increased at the timing when switching from the solidification process (step S7) to the sublimation process (step S8), but in the third embodiment, a large amount of nitrogen gas is discharged horizontally from the solidification process. That is, an airflow indicated by the dotted arrow starting from the peripheral gas outlet 67 in FIG. 6A in the semi-closed space SP is formed during the solidification process. This airflow causes the evaporated solvent atmosphere to flow toward the spin base 32 without stagnation above the space SP, promoting evaporation. It is possible to create an environment that is particularly favorable for evaporation of solvents that are difficult to volatilize (low vapor pressure).

As described above, the third embodiment provides the same effects as the first and second embodiments.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the substrate W is rotated at the second rotation speed V2 in the sublimable material sinking step (step S6c), but the rotation may be stopped.

In the above embodiment, the present invention is applied to an apparatus that performs the spin-off process (step S6b) and the sublimable material settling process (step S6c) in the liquid film formation process (step S6). However, this is not a required requirement of the present invention, and the present invention can also be applied to an apparatus that does not perform both steps or that performs only one of the steps.

The present invention can be applied to all substrate processing techniques that dry substrates using sublimable substances that change into gas without first passing through a liquid state.

1... Processing unit (substrate processing apparatus)
30...Spin chuck (substrate holding part)
31...Chuck pin (holding member)
32...Spin base (base member)
34...Substrate rotation drive mechanism (rotating unit)
50: opposing member 51: opposing plate 56: opposing plate lifting drive mechanism (moving unit)
60: central axis nozzle 61: nozzle body 66a: central gas outlet 67: peripheral gas outlet 513a: substrate facing surface 513b: central inclined surface 513c: inner peripheral surface 514: engagement member PT: pattern SP: space V1: first rotation speed V2: second rotation speed W: substrate Wf: surface (of substrate)

Claims (12)

a substrate holder having a base member and a plurality of holding members provided on a surface of the base member, the substrate holder holding the substrate by the plurality of holding members with a surface of the substrate facing upward;
a processing liquid supply unit that supplies a processing liquid, which contains a sublimable substance that changes into gas without passing through a liquid state and a solvent that dissolves in the sublimable substance, to a surface of the substrate held by the substrate holding unit;
a coagulate forming section for removing the solvent from the treatment liquid on the surface of the substrate to form a coagulate containing the sublimable substance;
a sublimation unit that sublimes the solidified material and removes it from the surface of the substrate;
an opposing member having a first opposing surface capable of opposing a surface of the substrate held by the substrate holding portion, and a second opposing surface capable of opposing an outer circumferential edge of the substrate held by the substrate holding portion and an outer circumferential edge of the base member;
a moving unit that moves the opposing member relatively to the substrate holding unit;
a gas supply unit that supplies an inert gas,
during a liquid film formation period in which the processing liquid is supplied to the surface of the substrate by the processing liquid supply unit to form a liquid film of the processing liquid on the surface of the substrate, the moving unit continues to bring the facing member close to the substrate holding unit to form a space surrounding the substrate by the facing member and the base member;
The gas supply unit supplies the inert gas to the space to create an inert gas-rich atmosphere in the space. The substrate processing apparatus according to claim 1 ,

The substrate processing apparatus supplies the inert gas before the liquid film formation period, thereby making the space have an inert gas-rich atmosphere. The substrate processing apparatus according to claim 1 ,
The gas supply unit supplies the inert gas to the space at least in an initial stage of the liquid film formation period. 3. The substrate processing apparatus according to claim 1,
The substrate processing apparatus makes the space into a low-oxygen environment having an oxygen concentration of 100 ppm or less by making the space into an inert gas-rich atmosphere. 4. The substrate processing apparatus according to claim 1 ,
a rotation unit that rotates the substrate held by the substrate holding unit about a rotation axis that is parallel to a vertical direction,
the processing liquid supply unit supplies the processing liquid only in an initial stage of the liquid film formation period,
The rotating part is
rotating the substrate at a first rotation speed in an initial stage of the liquid film formation period to spread the treatment liquid over the entire surface of the substrate;
and rotating the substrate at a second rotation speed lower than the first rotation speed at a final stage of the liquid film formation period, or stopping the rotation of the substrate to allow the sublimable material to sink between patterns formed on the surface of the substrate. The substrate processing apparatus according to claim 5 ,
The gas supply unit includes:
a first gas ejection port that ejects the inert gas parallel to the rotation axis toward a center of the surface of the substrate;
a second gas ejection port that ejects the inert gas radially from the rotation shaft toward a peripheral portion of the surface of the substrate;
a first gas discharge switching unit that switches between discharging and stopping the discharge of the inert gas from the first gas discharge port;
a second gas discharge switching unit that switches between discharging and stopping the discharge of the inert gas from the second gas discharge port;
A substrate processing apparatus comprising: The substrate processing apparatus according to claim 6 ,
In an initial stage of the liquid film formation period, the first gas discharge switching unit discharges the inert gas from the first gas discharge port and the second gas discharge switching unit discharges the inert gas from the second gas discharge port. 8. The substrate processing apparatus according to claim 6 ,
In a first half of a sublimable substance settling period in which the sublimable substance is settling, the first gas discharge switching unit stops discharging the inert gas from the first gas discharge port, and the second gas discharge switching unit stops discharging the inert gas from the second gas discharge port,
A substrate processing apparatus, wherein during a latter half of the sublimable material settling period, the second gas discharge switching unit continues to stop discharging the inert gas, while the first gas discharge switching unit discharges the inert gas from the first gas discharge port. 8. The substrate processing apparatus according to claim 6 ,
A substrate processing apparatus, wherein during a sublimable substance settling period in which the sublimable substance is settling, the first gas discharge switching unit stops discharging the inert gas from the first gas discharge port, while the second gas discharge switching unit discharges the inert gas from the second gas discharge port. 8. The substrate processing apparatus according to claim 6 ,
In a first half of a sublimable substance settling period in which the sublimable substance is settling, the first gas discharge switching unit stops discharging the inert gas from the first gas discharge port and the second gas discharge switching unit causes the inert gas to be discharged from the second gas discharge port,
A substrate processing apparatus in which, during a latter half of the sublimable material sinking period, the second gas discharge switching unit stops discharging the inert gas from the second gas discharge port and the first gas discharge switching unit discharges the inert gas from the first gas discharge port. 11. The substrate processing apparatus according to claim 6 ,
during a coagulation formation period in which the coagulation formation unit forms the coagulation, the first gas discharge switching unit stops discharging the inert gas from the first gas discharge port, and the second gas discharge switching unit discharges the inert gas from the second gas discharge port;
The substrate processing apparatus, wherein the first gas discharge switching unit discharges the inert gas from the first gas discharge port after the coagulation formation period has elapsed. a liquid film forming step of supplying a processing liquid containing a sublimable substance that changes into gas without passing through a liquid state and a solvent that dissolves in the sublimable substance to a surface of a substrate held by a plurality of holding members provided on a surface of a base member, thereby forming a liquid film of the processing liquid on the surface of the substrate;
a coagulation forming step of removing the solvent from the liquid film on the surface of the substrate to form a coagulation containing the sublimable substance;
a sublimation step of sublimating the solidified material and removing it from the surface of the substrate,
The liquid film forming step includes:
a step of continuously forming a space surrounding the substrate by the opposing member and the base member by placing a first opposing surface of the opposing member against a surface of the substrate held by the plurality of holding members and placing a second opposing surface of the opposing member against an outer peripheral edge of the base member;
supplying an inert gas into the space to create an inert gas-rich atmosphere in the space;
A substrate processing method comprising the steps of:

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