JP7446181B2 - Substrate processing method and substrate processing apparatus - Google Patents

Description

The present invention relates to a substrate processing method and a substrate processing apparatus for drying a substrate. Substrates include semiconductor wafers, substrates for liquid crystal display devices, and FPDs (Flat Panels) such as organic EL (electroluminescence) display devices.
This includes substrates for displays), optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, ceramic substrates, solar cell substrates, etc.

BACKGROUND ART Manufacturing processes for electronic components such as semiconductor devices and liquid crystal display devices include a process of forming a pattern by repeatedly performing processes such as film formation and etching on the surface of a substrate. Further, after this pattern formation, a cleaning process using a chemical solution, a rinsing process using a rinsing liquid, a drying process, etc. are performed in this order, and the importance of the drying process is particularly increasing as patterns become finer. In other words, techniques for suppressing or preventing pattern collapse during drying processing are important. Therefore, as described in Patent Document 1, for example, a substrate processing method and a substrate processing apparatus have been proposed in which a substrate is dried using a sublimable substance that changes into a gas without passing through a liquid.

JP2020-4948A

In the substrate processing technique 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 drying pretreatment liquid. The pre-drying treatment liquid is supplied to the surface of the substrate on which the pattern is formed. By vaporizing the solvent from the drying pretreatment liquid on the surface of the substrate, a solid film (corresponding to an example of the "coagulated material" of the present invention) made of a sublimable substance is formed over the entire surface of the substrate. The solid film is then removed from the surface of the substrate by sublimation.

In the conventional technology, sublimation of the solid film is performed by nitrogen gas discharged toward the center of the surface of the substrate. More specifically, the nozzle is arranged above the center of the surface of the substrate. Then, nitrogen gas is discharged from the nozzle toward the center of the surface of the substrate. Nitrogen gas is first supplied to the central region of the solid film, and then flows radially along the solid film to the periphery of the substrate. In parallel with this flow of nitrogen gas, vaporization of the sublimable substance progresses from the central region to the peripheral region of the solid film. Therefore, as will be described in detail later with reference to FIG. 8, the sublimable substance sublimated from the central region flows into the atmosphere above the peripheral region of the solid film together with nitrogen gas. Therefore, the concentration of the sublimable substance (gas) in the upper atmosphere increases, and sublimation in the peripheral region of the solid film may be suppressed. As a result, in the prior art, pattern collapse may occur at the peripheral edge of the surface of the substrate.

The present invention has been made in view of the above problems, and an object of the present invention is to improve pattern collapse at the peripheral edge of the surface of a substrate in a substrate processing technique that dries the substrate using sublimation of a sublimable substance.

One aspect of the present invention is a substrate processing method in which a coagulated substance containing a sublimable substance that changes into a gas without passing through a liquid is formed on the entire surface of a substrate, and the substrate is dried by sublimating the coagulated substance. A first sublimation step in which the first gas is discharged toward the center of the surface of the substrate and the first gas is distributed around the substrate via the entire solidified body to sublimate the entire solidified body; a second sublimation step of discharging a second gas towards the surface of the solidified body to flow the second gas around the substrate via the peripheral region on the surface peripheral portion of the solidified body to sublimate the peripheral region; , the second sublimation process starts earlier than the first sublimation process, and/or the flow rate of the second gas is higher than the flow rate of the first gas.

Another aspect of the present invention is a substrate processing apparatus that dries the substrate by sublimating the coagulated material from a substrate on which a coagulated material containing a sublimable substance that changes into a gas without passing through a liquid is formed over the entire surface. a first discharge part that discharges the first gas toward the center of the surface of the substrate; a second discharge part that discharges the second gas toward the peripheral edge of the surface of the substrate; The first gas is caused to flow around the substrate via the entire solidified body to sublimate the entire solidified body, and the second gas is discharged from the second discharge part to cause the second gas to flow around the substrate through the entire solidified body. a control section that causes the peripheral region of the substrate to flow through the peripheral region on the surface peripheral portion to sublimate the peripheral region; It is characterized by performing at least one of discharge timing control to advance the discharge timing and flow rate control to make the flow rate of the second gas larger than the flow rate of the first gas.

In the invention configured in this way, the second gas is applied to the peripheral region of the solidified body before the first gas, or a large amount of the second gas is applied to the peripheral region of the solidified body. Therefore, sublimation in the peripheral region of the coagulated body is promoted. As a result, pattern collapse at the peripheral edge of the surface of the substrate can be effectively prevented.

1 is a plan view showing a schematic configuration of a substrate processing system equipped with a first embodiment of a substrate processing apparatus according to the present invention. 2 is a side view of the substrate processing system shown in FIG. 1. FIG. 1 is a partial cross-sectional view showing the 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 the electrical configuration of a control system that controls a processing unit. FIG. 6 is a diagram schematically showing the positional relationship between the spin base, the substrate, and the opposing member when the opposing member is located at the opposing position. FIG. 3 is a partial cross-sectional view of the opposing member and the central axis nozzle. FIG. 3 is a schematic diagram of the vicinity of the lower end of the central axis nozzle viewed from below. 3 is a flowchart showing the content of substrate processing executed in the processing unit. FIG. 2 is a diagram illustrating sublimation processing performed in the prior art. It is a figure showing sublimation processing performed in a 1st embodiment of the present invention. It is a figure which shows the sublimation process performed in 2nd Embodiment of this invention. It is a figure which shows the sublimation process performed in 3rd Embodiment of this invention. It is a figure which shows the structure of the processing unit corresponding to 4th Embodiment of the substrate processing apparatus based on this invention. FIG. 13 is a plan view of the device shown in FIG. 12; FIG. 2 is a diagram schematically showing the configuration of a gas nozzle. FIG. 3 is a diagram of a gas nozzle viewed from vertically below. It is a figure which shows the sublimation process performed in 4th Embodiment of this invention. It is a figure which shows the structure of the processing unit corresponding to 5th Embodiment of the substrate processing apparatus based on this invention. FIG. 17 is a plan view of the device shown in FIG. 16;

FIG. 1 is a plan view showing a schematic configuration of a substrate processing system equipped with a first embodiment of a substrate processing apparatus according to the present invention. Further, 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 diagrams that clearly show the internal structure of the substrate processing system 100 by excluding the outer wall panels and other parts of the structure. This substrate processing system 100 is installed in, for example, a clean room, and is a single-wafer type device that processes one substrate W on which a circuit pattern or the like (hereinafter referred to as a "pattern") is formed only on one main surface. Then, the substrate processing method according to the present invention is executed in the processing unit 1 installed 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 among both main surfaces of the substrate is referred to as the "surface", and the opposite side The other main surface on which no pattern is formed is referred to as the "back surface." Further, the surface facing downward is referred to as the "lower surface", and the surface facing upward is referred to as the "upper surface". Furthermore, in this specification, the term "pattern-formed surface" refers to a surface on which a concavo-convex pattern is formed in an arbitrary region of the substrate.

Here, the "substrate" in this embodiment includes a semiconductor wafer, a glass substrate for a photomask, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, and a substrate for a magnetic disk. Various substrates such as substrates and magneto-optical disk substrates can be applied. The following explanation will be made with reference to the drawings, taking as an example a substrate processing apparatus mainly used for processing semiconductor wafers, but the invention is similarly applicable to the processing of the various substrates exemplified above.

As shown in FIG. 1, the substrate processing system 100 includes a substrate processing section 110 that processes a substrate W, and an indexer section 120 coupled to the substrate processing section 110. The indexer unit 120 includes a container C for accommodating the substrates W (FOUP (Front Opening Unified Pod) for accommodating a plurality of substrates W in a sealed state), a SMIF (Standard
It has a container holder 121 that can hold a plurality of pods (mechanical interface), OC (open cassette), etc.). The indexer section 120 is also an indexer for accessing the container C held in the container holding section 121 and taking out an unprocessed substrate W from the container C or storing a processed substrate W in the container C. A robot 122 is provided. Each container C accommodates a plurality of substrates W in a substantially horizontal posture.

The indexer robot 122 includes a base portion 122a fixed to the device housing, a multi-joint arm 122b rotatable around a vertical axis with respect to the base portion 122a, and a hand attached to the tip of the multi-joint arm 122b. 122c. The hand 122c has a structure that allows the substrate W to be placed and held on its upper surface. An indexer robot having such a multi-joint arm and a hand for holding a substrate is well known, so a detailed description thereof will be omitted.

The substrate processing unit 110 includes a mounting table 112 on which an indexer robot 122 places a substrate W, a substrate transfer robot 111 arranged approximately at the center in a plan view, and a plurality of substrate transfer robots 111 arranged so as to surround the substrate transfer robot 111. A processing unit 1 is provided. Specifically, a plurality of (eight in this example) processing units 1 are arranged facing the space where the substrate transfer robot 111 is arranged. For these processing units 1, the substrate transfer robot 111 randomly accesses the mounting table 112 and transfers the substrate W to and from the mounting table 112. On the other hand, each processing unit 1 executes a predetermined process on the substrate W. In this embodiment, these processing units 1 have the same function. Therefore, parallel processing of multiple substrates W is possible. Note that if the substrate transfer robot 111 can directly transfer the substrate W from the indexer robot 122, the mounting table 112 is not necessarily required. As each processing unit 1, processing units (1A to 1C) described below can be used.

FIG. 3 is a diagram showing the configuration of a processing unit corresponding to the first embodiment of the substrate processing apparatus according to the present invention. Further, FIG. 4 is a block diagram showing the electrical configuration of a control system that controls the processing unit. Note that in this embodiment, the control section 4 is provided for each processing unit 1A, but a configuration may be adopted in which a plurality of processing units 1A are controlled by one control section. Further, the processing unit 1A may be configured to be controlled by a control unit (not shown) that controls the entire substrate processing system 100.

The processing unit 1A includes a chamber 20 having an internal space 21, and a spin chuck 30 that is housed in the internal space 21 of the chamber 20 and holds the substrate W. As shown in FIGS. 1 and 2, a shutter 23 is provided on the side surface 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 opening/closing commands from the control unit 4. More specifically, in the processing unit 1A, when carrying the unprocessed substrate W into the chamber 20, the shutter opening/closing mechanism 22 opens the shutter 23, and the hand of the substrate transfer robot 111 moves the unprocessed substrate W into a face-up posture. Then, it is carried into the spin chuck 30. 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 transfer robot 111 retreats from the chamber 20 after carrying in the substrate, the shutter opening/closing mechanism 22 closes the shutter 23 . Then, in the internal space 21 of the chamber 20, a chemical solution, DIW (deionized water), IPA (isopropyl alcohol) treatment liquid, drying pretreatment liquid, and nitrogen gas are supplied to the surface Wf of the substrate W to form a desired surface Wf. Substrate processing is performed in a room temperature environment. Further, after the substrate processing is finished, the shutter opening/closing mechanism 22 opens the shutter 23 again, and the hand of the substrate transfer robot 111 carries out 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 in which substrate processing is performed while maintaining the room temperature environment. In this specification, "normal temperature" means a temperature range of 5°C to 35°C.

The spin chuck 30 has a plurality of chuck pins 31. In the spin chuck 30, a plurality of chuck pins 31 are provided at the periphery of the upper surface of a disc-shaped spin base 32. In this embodiment, the chuck pins 31 are arranged at appropriate intervals (eg, equal intervals) in the circumferential direction of the spin base 32 and grip the peripheral edge of the substrate W. As a result, the substrate W is held by the spin chuck 30.

A rotating shaft 33 is connected to the spin base 32 . The rotation shaft 33 is rotatably provided around a rotation axis AX1 extending from the center of the surface of the substrate W supported by the spin chuck 30 and parallel to the surface normal. The rotation 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 is operated 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 pin 31, the substrate W is rotated according to the rotation command. It rotates around the rotation axis AX1 at a corresponding rotation speed. In addition, while the substrate W is rotated in this manner, chemical solutions, IPA processing solution, DIW, and pre-drying processing solution are supplied from the central shaft nozzle 60 that vertically penetrates the opposing member 50 in response to a supply command from the control unit 4. and nitrogen gas are supplied to the surface Wf of the substrate W.

FIG. 5 is a diagram schematically showing the positional relationship between the spin base, the substrate, and the opposing member when the opposing member is located at the opposing position. The opposing member 50 is a driven opposing member that rotates according to the spin chuck 30, as shown in FIGS. 3 and 5. 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. In order to make this possible, the facing member 50 engages with the facing plate 51, an engaging member 52 provided on the facing plate 51 so as to be able to move up and down along with the facing plate 51, and moves the facing plate 51 from above. It has a support part 53 for supporting.

The opposing plate 51 has a disk shape larger than the diameter of the substrate W, and has a cap shape that covers the substrate W from vertically above. More specifically, the opposing plate 51 includes a disk portion 511 held in a horizontal position and a cylindrical portion 512 extending downward from the outer circumference of the disk portion 511. The inner surface 513 of the opposing plate 51 is a cup surface recessed 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 as a flat surface parallel to the upper surface of the substrate W, and faces the front surface Wf of the substrate W.

Further, the central inclined surface 513b has an inclined surface surrounded by the substrate facing surface 513a. More specifically, the central inclined surface 513b has an annular central inclined portion extending 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 inclined surface with a constant inclination angle with respect to the rotation axis AX1. The cross section of the central slope is open 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 FIGS. 6A and 6B, which will be described later).

Further, the inner peripheral surface 513c corresponds to the inner surface of the cylindrical portion 512. More specifically, the inner circumferential surface 513c has an annular inner slope extending diagonally downward and outward from the substrate facing surface 513a, and has the following characteristics. The inner inclined portion has an arcuate cross section whose inclination angle with respect to the rotation axis AX1 changes continuously. The cross section of the inner slope is open downward. The inner diameter of the inner circumferential surface 513c increases as it approaches the lower end of the inner circumferential 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, the opposing member 50 is in the opposing position and faces the outer peripheral end of the substrate W and the outer peripheral surface (outer peripheral end) 32b of the spin base 32.

The facing plate 51 further includes a plurality of second engaging members 514 provided on the substrate facing surface 513a and for engaging with the first engaging members 35. A through hole 515 that vertically passes through the facing member 50 is formed in the center of the substrate facing surface 513a. The through hole 515 is defined by a cylindrical inner peripheral 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 . Note that the configurations of the first engaging member 35 and the second engaging member 514 are conventionally well known. For example, the configuration described in JP-A No. 2019-57599 can be used as the engaging members 35 and 514 of this embodiment. When the first engagement member 35 and the second engagement member 514 engage with each other, the opposing member 50 is supported by the spin base 32 via the engagement 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 engaging member 52 includes a cylindrical portion 521 surrounding the through hole 515 and a flange portion 522 extending radially outward from the upper end of the cylindrical portion 521 on the upper surface of the opposing plate 51. have. The flange portion 522 is located above the flange support portion 531, which is a component of the support portion 53, and the outer circumference of the flange portion 522 has a larger diameter than the inner circumference of the flange support portion 531.

The support portion 53 includes 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, that is, the rotation axis AX1, so as to pass through the internal space of the supporting part 53 and the opposing plate 51. There is. Further, the central shaft nozzle 60 is raised and lowered together with the support portion 53 by the opposing plate raising and lowering drive mechanism 56. For example, when the central axis nozzle 60 and the opposing member 50 are positioned at a retracted position vertically upward from the substrate W as shown by the solid line in FIG. It is spaced apart upward from the surface Wf of the substrate W. Then, in response to a lowering command from the control unit 4, the opposing plate elevating drive mechanism 56 lowers the central shaft nozzle 60 and the support unit 53, and as shown in the dashed line in FIG. 3 and in FIG. to the opposite position. Thereby, the opposing plate 51 of the opposing member 50 approaches the front surface Wf of the substrate W. As a result, the substrate W held on the spin chuck 30 is surrounded by the substrate facing surface (first facing surface) 513a, the inner peripheral surface (second facing surface) 513c, and the outer peripheral surface (outer peripheral end) 32b of the spin base 32. A semi-closed space SP is formed. Then, while the substrate W is confined in the semi-sealed space SP and isolated from the surrounding atmosphere, as shown in FIGS. 6A and 6B, the chemical solution, IPA processing solution, DIW, drying pretreatment solution and nitrogen are supplied from the central axis nozzle 60. Gas is supplied to the surface Wf of the substrate W.

FIG. 6A is a partial cross-sectional view of the opposing member and central axis nozzle. FIG. 6B is a schematic diagram of the vicinity of the lower end of the central axis nozzle viewed from below. The dotted line area in FIG. 6A is a partially enlarged view of the front surface Wf of the substrate W, and shows an example of the pattern PT formed on the front surface Wf. The central axis nozzle 60 has a nozzle body 61 extending vertically along the rotation axis AX1. Five central piping portions (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 openings on the lower end side of the five central piping portions function as a chemical solution outlet 62a, a DIW outlet 63a, an IPA outlet 64a, a drying pretreatment liquid outlet 65a, and a central gas outlet 66a, respectively.

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

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 installed in this pipe 63b. Therefore, when the valve 63c is opened in response to an opening/closing command from the control unit 4, the IPA processing liquid is supplied to the center axis nozzle 60 via the pipe 63b, and directed from the DIW outlet 63a toward the center of the surface of the substrate W. is discharged. In this embodiment, as will be described later, DIW is used as a rinsing liquid for rinsing the surface Wf of the substrate W after chemical treatment, but other rinsing liquids may be used. For example, carbonated water, electrolyzed ionized water, hydrogen water, ozone water, or diluted hydrochloric acid water (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 discharge port 64a is connected to an IPA processing liquid supply section (not shown) via a piping 64b. A valve 64c is installed in this pipe 64b. Therefore, when the valve 64c is opened in response to an opening/closing command from the control unit 4, the IPA processing liquid is supplied to the center axis nozzle 60 via the pipe 64b, and directed from the IPA discharge port 64a toward the center of the surface of the substrate W. is discharged. In this embodiment, the IPA processing liquid is used as a replacement liquid to replace the rinsing liquid (DIW) that adheres to the surface Wf of the substrate W after the rinsing process, but other liquids may be used. More specifically, a liquid that is soluble in both the rinsing liquid and the pre-drying liquid can 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 components other than these.

As shown in FIG. 3, the central piping section having the drying pretreatment liquid discharge port 65a is connected to a drying pretreatment liquid supply section (not shown) via a piping 65b. A valve 65c is installed in this pipe 65b. Therefore, when the valve 65c is opened in response to an opening/closing command from the control unit 4, the drying pretreatment liquid is supplied to the central axis nozzle 60 via the pipe 65b, and the surface of the substrate W is supplied from the drying pretreatment liquid discharge port 65a. It is discharged towards the center. 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 drying pretreatment liquid. Here, a sublimable substance is a substance that changes from a solid to a gas without passing through a liquid state at normal temperature (synonymous with room temperature) or normal pressure (pressure inside the processing unit 1A, for example, a value of 1 atmosphere or its vicinity). Good too. The solvent may be such a substance or another substance. That is, the drying pretreatment liquid may contain two or more types of substances that change from solid to gas at room temperature or pressure without passing through the liquid state.

Sublimable substances include, for example, alcohols such as 2-methyl-2-propanol (also known as tert-butyl alcohol, t-butyl alcohol, tert-butyl alcohol) and cyclohexanol, fluorinated hydrocarbon compounds, 1,3, It may be any one of 5-trioxane (also known as metaformaldehyde), camphor (also known as camphor, camphor), naphthalene, iodine, cyclohexanone oxime, and cyclohexane, or it may be a substance other than these.

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

As shown in FIG. 3, the central piping section having the central gas discharge port 66a is connected to a nitrogen gas supply section (not shown) via a piping 66b. A valve 66c is installed in this pipe 66b. Therefore, when the valve 66c is opened in response to an opening/closing command from the control unit 4, nitrogen gas is supplied to the center shaft nozzle 60 via the pipe 66b, and as shown by the dashed line arrow in FIG. The gas is discharged toward the center of the surface of the substrate W from the gas discharge port 66a. As described above, in this embodiment, the central gas discharge port 66a corresponds to an example of the "first discharge part" of the present invention. Further, the nitrogen gas discharged from the central gas discharge port 66a corresponds to an example of the "first gas" of the present invention, and is appropriately referred to as "vertical N2" below.

As shown by the solid line in FIG. 3, the lower end surface 61a provided with the five discharge ports 62a to 66a is retracted upward from the substrate facing surface 513a and the central inclined surface 513b in the non-blocking state. On the other hand, in the shut-off state, as shown in FIGS. 6A and 6B, the lower end surface 61a is located at the same height in the vertical direction as the substrate facing surface 513a, and the lower end portion 61b of the nozzle body 61 is surrounded by the central inclined surface 513b. It is exposed downward from the through hole 515 in a closed state.

Six peripheral gas discharge ports 67 are provided on the side surface of the lower end portion 61b at approximately equal angular intervals around the rotation axis AX1. A peripheral piping portion 68 extending from the side surface of the nozzle body 61 to the upper end surface of the nozzle body 61 is connected to these peripheral gas discharge ports 67 . As shown in FIG. 3, the peripheral piping section 68 is connected to a nitrogen gas supply section (not shown) via a piping 68b. A valve 68c is installed in this pipe 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 from the peripheral gas discharge port 67 approximately horizontally about the rotation axis AX1. discharged in the direction. As described above, in this embodiment, the peripheral gas discharge port 67 corresponds to an example of the "second discharge part" of the present invention. Further, the nitrogen gas discharged from the peripheral gas discharge port 67 corresponds to an example of the "second gas" of the present invention, and is appropriately referred to as "horizontal N2" below to distinguish it from the vertical N2. This horizontal N2 is guided toward the surface periphery 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 as follows.
- A first supply mode (dotted chain line arrow in the same figure) in which the liquid is supplied to the peripheral edge of the surface of the substrate W via the center of the surface of the substrate W;
- A second supply mode (dotted line arrow in the figure) in which the liquid is supplied to the peripheral edge of the surface of the substrate W without passing through the center of the surface of the substrate W;
exists. The control unit 4 controls the opening and closing of the valves 66c and 68c to provide a mode in which the supply of nitrogen gas is stopped, a mode in which only the first supply mode is executed, and a mode in which only the second supply mode is executed. A mode in which the first supply mode and the second supply mode are executed simultaneously is selectively switched. Although not shown in the figure, the flow rate of nitrogen gas supplied in the first supply mode and the second supply mode can be independently and variably controlled in accordance with commands from the control unit 4. There is. Note that in this embodiment, nitrogen gas is used as the "inert gas" of the present invention, but in addition to this, an inert gas such as dehumidified argon gas may be used.

In the processing unit 1A, an exhaust bucket 70 is provided to surround the spin chuck 30. Additionally, a plurality of cups 72 are arranged between the spin chuck 30 and the exhaust bucket 70, and a plurality of guards are provided to catch the chemical liquid, rinsing liquid (DIW), IPA treatment liquid, and drying pretreatment liquid scattered around the substrate W. 73 is provided. Further, a guard lifting/lowering drive mechanism 71 is connected to the guard 73 . The guard lifting/lowering drive mechanism 71 independently lifts/lowers the guard 73 in response to a lifting/lowering command from the control section 4 . Further, an exhaust mechanism 74 is connected to the exhaust bucket 70 via a pipe 75. This exhaust mechanism 74 exhausts a space surrounded by the inner bottom surface of the chamber 20, the exhaust bucket 70, and the guard 73.

Further, the processing unit 1A is provided with three flowmeters 81 to 83 to monitor the flow rate of gas components in each part of the apparatus. More specifically, the first flow meter 81 is attached to the disk portion 511 so as to face the semi-closed space SP. The first flow meter 81 measures the flow rate of the gas component within the space SP, and outputs the measurement result to the control unit 4. A second flow meter 82 is attached to the spin chuck 30 so as to face the space around the spin chuck 30. The second flowmeter 82 measures the flow rate of the gas component in the atmosphere surrounding the spin chuck 30 and outputs the measurement result to the control unit 4. A first flow meter 81 is attached to a pipe 75 extending from the exhaust bucket 70 to the exhaust mechanism 74. The third flow meter 83 measures the flow rate of the gas component flowing through the pipe 75 and outputs the measurement result to the control section 4.

The control unit 4 includes an arithmetic unit such as a CPU, a fixed memory device, a storage unit such as a hard disk drive, and an input/output unit. The storage unit stores a program executed by the arithmetic unit. Then, the control section 4 executes the substrate processing shown in FIG. 7 by controlling each section of the apparatus according to the above program. In particular, as will be explained below, the control unit 4 controls the discharge timing to make the horizontal N2 discharge start earlier than the vertical N2 discharge start and the flow rate control to make the horizontal N2 flow rate higher than the vertical N2 flow rate in the sublimation process. By doing this, pattern collapse at the peripheral edge of the surface of the substrate W is improved.

FIG. 7 is a flowchart showing the contents of substrate processing executed in the processing unit. The processing target in the substrate processing system 100 is, for example, a silicon wafer, and an uneven pattern PT (see FIG. 6A) is formed on the surface Wf, which is a pattern formation surface. The pattern PT may constitute a logic circuit, a DRAM (Dynamic Random Access Memory), or a PRAM (Phase-change Random Access Memory) that utilizes the unique properties of a chalcogenide alloy. The pattern PT may be a pattern in which linear patterns formed by fine trenches are repeatedly arranged. Further, the pattern PT may be formed by providing a plurality of micro holes (voids or pores) in the thin film. Pattern PT includes, for example, an insulating film. Further, the pattern PT may include a conductive film. More specifically, the pattern PT is formed of a laminated film in which a plurality of 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. Furthermore, the conductor film may be an amorphous silicon film into which impurities are introduced to lower the resistance, or a metal film (for example, a TiN film). Furthermore, the pattern PT may be formed at the front end or at the back end. Furthermore, the pattern PT may be a hydrophobic film or a hydrophilic film. Examples of the hydrophilic film include a TEOS film (a type of silicon oxide film).

Further, each step shown in FIG. 7 is performed under an atmospheric pressure environment unless otherwise specified. Here, the atmospheric pressure environment refers to an environment of 0.7 atm or more and 1.3 atm or less, centering on standard atmospheric pressure (1 atm, 1013 hPa). In particular, when the substrate processing system 100 is placed in a clean room with positive pressure, the environment on the surface Wf of the substrate W is higher than 1 atmosphere.

Before the unprocessed substrate W is carried into the processing unit 1A, the control section 4 gives commands to each part of the apparatus, and the processing unit 1A is set to an 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 opened by a chuck opening/closing mechanism (not shown). The opposing plate 51 is positioned at a retracted position by an opposing plate lifting/lowering drive mechanism 56. As a result, the support of the opposing plate 51 by the spin base 32 is released, and the rotation of the opposing plate 51 is stopped. All the guards 73 are moved downward and positioned. Furthermore, all valves 62c to 66c and 68c are closed.

When the unprocessed substrate W is transported by the substrate transport robot 111, the shutter 23 opens. When the shutter 23 is opened, the substrate W is carried into the internal space 21 of the chamber 20 by the substrate transfer robot 111, and is delivered to the spin chuck 30 in a face-up state with the surface Wf facing upward. Then, the chuck pins 31 are brought into a closed state, and the substrate W is held by the spin chuck 30 (step S1: substrate loading).

Following the loading of the substrate W, the substrate transfer robot 111 retreats outside the chamber 20, and the shutter 23 closes again. After that, the control unit 4 controls the opposing plate elevation drive mechanism 56 to arrange the opposing plate 51 at the opposing position. As a result, as shown in FIG. 5, the engaging member 514 provided on the opposing plate 51 is received by the engaging member 35, and the opposing plate 51 and the central axis nozzle 60 are supported by the spin base 32. Further, the facing 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 cut off from the surrounding atmosphere. In addition, in this embodiment, the opposing plate 51 is positioned at 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 adjust the rotation speed of the spin base 32 to a predetermined chemical processing speed (approximately 10 ~1200 rpm, for example to about 800 rpm), and maintain that chemical solution processing speed. Along with this rotation of the spin base 32, the opposing plate 51 is rotated around the rotation axis AX1, and the substrate W is rotated around the rotation axis AX1 (step S2: substrate rotation start). Note that, before proceeding to the next chemical treatment, the control unit 4 raises the guard 73 corresponding to the chemical treatment so that the guard 73 is connected to the inner circumferential surface 513c of the opposing plate 51 and the outer circumferential surface 32b of the spin base 32. facing the gap GP.

When the rotational speed of the substrate W reaches the chemical processing speed, the control section 4 then opens the valve 62c. As a result, the chemical liquid is discharged from the chemical liquid discharge port 62a of the central axis nozzle 60 and supplied to the surface Wf of the substrate W. On the surface Wf of the substrate W, the chemical liquid moves to the peripheral edge of the substrate W under the influence of centrifugal force caused by the rotation of the substrate W. As a result, the entire surface Wf of the substrate W is subjected to chemical cleaning with the chemical liquid (step S3). At this time, the chemical solution that has reached the peripheral edge of the substrate W is discharged from the peripheral edge of the substrate W to the side of the substrate W, and is sent via the guard 73 to waste liquid processing equipment outside the machine. This chemical cleaning by supplying the chemical continues for a predetermined cleaning time, and after that time, the control unit 4 closes the valve 62c and stops discharging the chemical from the central shaft nozzle 60.

Following the chemical cleaning, a rinsing process using a rinsing liquid (DIW) is performed (step S4). In this DIW rinse, the control section 4 opens the valve 63c. As a result, DIW is supplied as a rinse liquid from the DIW discharge port 63a of the central axis nozzle 60 to the center of the front surface Wf of the substrate W that has undergone the chemical cleaning process. Then, the DIW receives centrifugal force due to the rotation of the substrate W and moves to the peripheral edge of the substrate W. As a result, the chemical solution adhering to the substrate W is washed away by the DIW. At this time, the DIW discharged from the peripheral edge of the substrate W is discharged from the peripheral edge of the substrate W to the side of the substrate W, and is sent to a waste liquid processing facility outside the machine in the same manner as the chemical solution. This DIW rinsing is continued for a predetermined rinsing time, and after that time, the control unit 4 closes the valve 63c and stops discharging DIW from the central axis nozzle 60.

After completion of DIW rinsing, replacement processing (step S5) is performed. 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 rotational speed of the substrate W to a predetermined replacement rotational speed, and maintains the rotational speed at the replacement rotational speed. . Further, the control unit 4 adjusts the flow rates of nitrogen gas from the central gas discharge port 66a and the peripheral gas discharge port 67, that is, the flow rates of vertical N2 and horizontal N2, respectively. As a result, nitrogen gas is supplied to the semi-closed space SP, and the space SP becomes nitrogen-rich. Furthermore, 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 point that communicates the space SP with the surrounding atmosphere. As a result, the space SP becomes a hypoxic environment. Here, "low oxygen" refers to an oxygen concentration of 100 ppm or less.

Further, the control unit 4 causes the guard 73 corresponding to the replacement process to face the gap GP. Then, the control unit 4 opens the valve 64c. Thereby, the IPA processing 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 is spread over the entire surface Wf of the substrate W by the centrifugal force caused by the rotation of the substrate W. As a result, DIW (rinsing liquid) adhering to the surface Wf of the substrate W is replaced with the IPA treatment liquid over the entire surface Wf of the substrate W. The IPA processing 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, is received by the guard 73, and is sent to the recovery equipment along a recovery path (not shown). It will be done. This IPA replacement continues for a predetermined replacement time, and after that time, the control unit 4 closes the valve 64c and stops discharging the IPA processing liquid from the central axis nozzle 60.

After IPA replacement, a pre-drying treatment liquid supply process (step S6) is executed. In this pre-drying treatment liquid supply process, the control unit 4 maintains the rotational speed of the substrate W, the vertical N2 flow rate, and the horizontal N2 flow rate at the values in the replacement process. The control unit 4 causes the guard 73 corresponding to the drying pretreatment liquid supply process to face the gap GP. The control unit 4 opens the valve 65c. Thereby, the drying pretreatment liquid is discharged from the drying pretreatment liquid discharge port 65a of the central axis nozzle 60 toward the center of the surface Wf of the substrate W to which the replacement liquid is attached. The drying pretreatment liquid supplied to the surface Wf of the substrate W is spread over the entire surface Wf of the substrate W by the centrifugal force caused by the rotation of the substrate W. As a result, the IPA treatment liquid is replaced with the drying pretreatment liquid over the entire surface Wf of the substrate W, and a relatively thick liquid film of the drying pretreatment liquid is formed. Discharging of the drying pretreatment liquid is continued for a predetermined period of time, and after that time, the control unit 4 closes the valve 65c to stop discharging the drying pretreatment liquid from the central axis nozzle 60.

In order to thin the liquid film thus formed to a desired thickness, a film thickness reduction process (step S7) is performed. In the film thickness reduction process, the control unit 4 closes the valves 66c and 68c to stop discharging vertical N2 and horizontal N2, and controls the motor (not shown) of the substrate rotation drive mechanism 34 to adjust the rotation speed of the substrate W. is increased to a spin-off speed higher than the displacement rotation speed. Then, the control unit 4 maintains the spin-off speed for a predetermined time. As a result, the excess drying pretreatment liquid is removed from the surface Wf of the substrate W, and the thickness of the liquid film of the drying pretreatment liquid is adjusted to a desired thickness. Note that in this embodiment, the supply of nitrogen gas to the space SP is stopped during the film thickness reduction process, but the supply of nitrogen gas may be continued.

Next, a solidified body forming process (step S8) is performed in which the pre-drying treatment liquid on the substrate W is solidified and a solidified body containing a sublimable substance is formed on the surface Wf of the substrate W. In this solidified body forming process, the control unit 4 controls the motor (not shown) of the substrate rotation drive mechanism 34 to adjust the rotational speed of the substrate W to the solidified body forming speed. This coagulation formation speed may be the same as the displacement rotation speed or may be higher. Further, the control unit 4 opens at least one of the valves 66c and 68c to discharge nitrogen gas in order to promote coagulation formation. This coagulation formation process promotes evaporation of the drying pretreatment liquid, and a portion of the drying pretreatment liquid on the substrate W evaporates. While the concentration of the sublimable substance in the liquid film gradually increases, the thickness of the liquid film gradually decreases. Then, a solidified body (symbol SB in FIGS. 8 to 11 and 15) corresponding to a solidified film covering the entire upper surface of the substrate W is formed.

Following this solidified body formation process, a sublimation process (step S9) is performed in which the solidified body on the surface Wf of the substrate W is sublimated and removed from the surface Wf of the substrate W. The control unit 4 adjusts the rotation speed of the substrate W to the sublimation speed. This sublimation rate may be equal to or different from the final rate of the coagulum formation step. Further, the control unit 4 supplies nitrogen gas to the solidified body SB. Here, for example, as shown in FIG. 8, if the sublimation process is performed using the same method as in the prior art, that is, only by supplying vertical N2, the above-mentioned problem will occur.

FIG. 8 is a diagram showing a sublimation process performed in the conventional technique. The horizontal axis of the upper graph in the figure (and a similar graph described later) indicates the elapsed time from the start of sublimation, and the vertical axis indicates the vertical N2 flow rate. In the prior art, nitrogen gas is supplied to the surface Wf of the substrate W only by the first supply mode shown by the dashed-dotted line arrow in FIG. 6A. In other words, the vertical N2 extends over the entire surface of the substrate W via the center of the surface of the substrate W. Therefore, as shown in the lower schematic diagram of FIG. 8, in the initial stage of the sublimation process (timing T01), the gaseous sublimable substance SS sublimated on the surface layer portion of the solidified body SB is mixed with the nitrogen gas on the surface Wf of the substrate W. be excluded from However, at timing T02 after a certain amount of time has elapsed, fresh nitrogen gas is always supplied to the central region SB1 of the solidified body SB located on the peripheral edge of the surface of the substrate W; Nitrogen gas containing a high concentration of sublimable substance SS flows into the peripheral region SB2 of the solidified body SB located on the peripheral portion. Therefore, the degree of progress of the sublimation process is different between the central region SB1 and the peripheral region SB2 of the solidified body SB. More specifically, sublimation of the peripheral edge region SB2 may be suppressed, and this is one of the main causes of pattern collapse at the peripheral edge of the surface of the substrate W. Therefore, in this embodiment, the above problem is solved by preparing two types of nitrogen gas supply modes and controlling their ON/OFF as appropriate.

FIG. 9 is a diagram showing the sublimation process performed in the first embodiment of the present invention. In this embodiment, at the start of the sublimation process (step S9), the control unit 4 closes the valve 66c to stop discharging vertical N2, and opens the valve 68c to start discharging horizontal N2 at a flow rate F2. . As a result, while only the horizontal N2 is being supplied, fresh nitrogen gas that does not contain the sublimable substance SS is constantly supplied to the peripheral region SB2. As a result, for example, at timing T11, sublimation of the peripheral region SB2 progresses. On the other hand, since nitrogen gas is not supplied to the central region SB1 of the solidified body SB, sublimation of the central region SB1 is regulated.

In this way, at the timing Tsw when the sublimation of the peripheral region SB2, which corresponds to an example of the "second sublimation step" of the present invention, has progressed preferentially or has been completed, the control unit 4 closes the valve 66c while keeping the valve 68c open. It opens and starts discharging vertical N2 at a flow rate F1 (<F2). As a result, for example, as shown in the schematic diagram at timing T12 (lower right diagram in the figure), fresh nitrogen gas is supplied to the central region SB1, and the entire solidified body SB including the central region SB1 is Sublimation is progressing. This corresponds to an example of the "first sublimation step" of the present invention. Furthermore, fresh horizontal N2 continues to be supplied to the peripheral region SB2, and the concentration of the sublimable substance SS is kept low. Therefore, even if the sublimation of the peripheral area SB2 is not completed at the timing Tsw, the sublimation of the peripheral area SB2 continues. As a result, the entire coagulated body SB is reliably sublimated and removed by the sublimation process (step S9).

Returning to FIG. 7, the explanation will be continued. After the sublimation process, the control unit 4 controls the motor of the substrate rotation drive mechanism 34 to stop the rotation of the substrate W (step S10: stop substrate rotation). Subsequently, the control unit 4 controls the opposing plate elevating drive mechanism 56 to raise the opposing plate 51 from the opposing position and position it at the retracted position. Further, the control unit 4 retracts all the guards 73 downward from the gap GP.

Thereafter, after the control unit 4 controls the shutter opening/closing mechanism 22 to open the shutter 23 (FIGS. 1 to 3), the substrate transfer robot 111 enters the internal space of the chamber 20 and is held by the chuck pin 31. The released processed substrate W is carried out of the chamber 20 (step S10). Note that when the substrate transfer robot 111 leaves the processing unit 1A after the substrate W is completely unloaded, the control section 4 controls the shutter opening/closing mechanism 22 to close the shutter 23.

As described above, in the first embodiment, prior to sublimating the entire solidified body SB by supplying vertical N2, horizontal N2 is supplied to the peripheral area SB2 of the solidified body SB, and the horizontal N2 is preferentially applied to the peripheral area SB2. Sublimation is taking place. Further, after starting the supply of vertical N2, the flow rate F2 of horizontal N2 is set to be larger than the flow rate F1 of vertical N2. Therefore, after the vertical N2 supply starts, the concentration of the sublimable substance SS in the nitrogen gas (=vertical N2+horizontal N2) flowing into the peripheral region SB2 is low. Therefore, even if part of the peripheral region SB2 is unsublimated at the time of starting the supply of the vertical N2, sublimation of the unsublimated part is performed in parallel with sublimation of the central region SB1. Therefore, according to the first embodiment, pattern collapse at the peripheral edge of the surface of the substrate W can be improved.

FIG. 10 is a diagram showing the sublimation process performed in the second embodiment of the present invention. The only major difference between the second embodiment and the first embodiment is the flow rate control of vertical N2 (first gas) and horizontal N2 (second gas) after the start of discharging vertical N2. The other configurations are the same as the first embodiment. Therefore, in the following, the differences will be mainly explained, and the same components will be given the same reference numerals and the explanation will be omitted.

In the second embodiment, in the sublimation process (step S9), at the timing Tsw when the sublimation of the peripheral area SB2 has progressed preferentially or when the sublimation has been completed, the control unit 4 opens the valve 66c and gradually reduces the flow rate of the vertical N2. After gradually decreasing the horizontal N2 flow rate, the valve 68c is closed to stop the horizontal N2 supply.

According to this second embodiment, the following effects can be obtained. The peripheral region SB2 of the solidified body SB is preferentially sublimated, and the peripheral region SB2 to be sublimated after the timing Tsw is zero or a small amount. Therefore, by reducing the flow rate of the horizontal N2 that primarily contributes to the sublimation of the peripheral region SB2 after the timing Tsw, the amount of nitrogen gas consumed and the amount of exhaust by the exhaust mechanism 74 can be suppressed. As a result, running costs can be reduced.

FIG. 11 is a diagram showing the sublimation process performed in the third embodiment of the present invention. A major difference between the third embodiment and the first embodiment is the start timing of vertical N2 discharge. The other configurations are the same as the first embodiment. Therefore, in the following, the differences will be mainly explained, and the same components will be given the same reference numerals and the explanation will be omitted.

In the third embodiment, from the start of the sublimation process (step S9), the control unit 4 opens the valve 66c to start discharging vertical N2 at a flow rate F1, and opens the valve 68c to discharge horizontal N2 at a flow rate F2. Start. As a result, the vertical N2 is supplied to the central part of the surface of the substrate W, and sublimation of the central region SB1 of the solidified body SB progresses. The gaseous sublimable substance SS generated at this time is contained in the nitrogen gas and flows to the surface periphery. Therefore, the sublimable substance SS exists at the peripheral edge of the surface. However, in the third embodiment, the horizontal N2 is supplied toward the surface periphery of the substrate W at a flow rate F2 greater than the flow rate F1 of the vertical N2 from the start of the sublimation process. Therefore, the concentration of the sublimable substance in the nitrogen gas (=vertical N2+horizontal N2) at the surface periphery is relatively low, and the nitrogen gas sublimates the peripheral region SB2 in parallel with the sublimation of the central region SB1.

As described above, in the third embodiment, the control unit 4 controls the flow rate so that the flow rate F2 of the horizontal N2 (second gas) is larger than the flow rate F1 of the vertical N2 (first gas). As a result, pattern collapse at the peripheral edge of the surface of the substrate W can be improved.

By the way, in the first to third embodiments described above, the processing unit 1A that processes the substrate is formed by forming the semi-sealed space SP by bringing the opposing plate 51 of the opposing member 50 close to the front surface Wf of the substrate W. However, the present invention is not limited to this. For example, the present invention can be applied to the apparatus described in Patent Document 1, that is, a substrate processing apparatus that processes a substrate with the lower surface of the shielding plate disposed close to and parallel to the upper surface of the substrate. Further, a processing unit (fourth embodiment) that processes a substrate using a gas nozzle smaller than the opposing plate 51 and the blocking plate, that is, smaller than the outer diameter of the substrate W, and a scan nozzle that scans along the surface Wf of the substrate W. The present invention can also be applied to a processing unit (fifth embodiment) that processes a substrate.

FIG. 12 is a diagram showing the configuration of a processing unit corresponding to the fourth embodiment of the substrate processing apparatus according to the present invention. FIG. 13 is a plan view of the device shown in FIG. 12. FIG. 14A is a diagram schematically showing the configuration of a gas nozzle. FIG. 14B is a diagram of the gas nozzle viewed from vertically below. The fourth embodiment is largely different from the first embodiment in the configuration for supplying the chemical solution, DIW, IPA treatment liquid, drying pretreatment liquid, and nitrogen gas to the substrate W. The other configurations are the same as the first embodiment. Therefore, in the following, the differences will be mainly explained, and the same components will be given the same reference numerals and the explanation will be omitted.

The processing unit 1B has a gas nozzle 54 that forms an airflow that protects the surface Wf of the substrate W held by the spin chuck 30. The gas nozzle 54 has a nozzle body 540 having an outer diameter smaller than the diameter of the substrate W. Two gas discharge ports 541 and 542 are provided on the outer peripheral surface of this nozzle body 540. The gas discharge ports 541 and 542 are annular slits continuous in the circumferential direction over the entire circumference of the gas nozzle 54, and can discharge nitrogen gas radially above the substrate W, respectively. The gas discharge ports 541 and 542 are arranged above the lower surface of the gas nozzle 54. The gas discharge port 542 is arranged above the gas discharge port 541. Note that the diameters of the gas discharge ports 541 and 542 may be equal to each other or may be different from each other.

The gas discharge port 541 is connected to a piping portion 543 that connects from the side surface of the nozzle body 540 to the upper end surface, as shown in FIG. 14A. The piping section 543 is connected to a nitrogen gas supply section (not shown) via a piping 544b. A valve 544c is installed in this pipe 544b. Therefore, when the valve 544c is opened in response to an opening/closing command from the control unit 4, nitrogen gas is supplied to the nozzle body 540 via the pipe 544b, and is discharged from the gas discharge port 541 radially around the rotation axis AX1. Ru.

The gas discharge port 542 is connected to a piping portion 545 that connects from the side surface of the nozzle body 540 to the upper end surface. As shown in FIG. 14A, the piping section 545 is connected to a nitrogen gas supply section (not shown) via a piping 546b. A valve 546c is installed in this pipe 546b. Therefore, when the valve 546c is opened in response to an opening command from the control unit 4, nitrogen gas is supplied to the nozzle body 540 via the pipe 546b, and is discharged from the gas discharge port 542 radially around the rotation axis AX1. Ru.

Therefore, when both valves 544c, 546c are opened, a plurality of overlapping annular air flows are formed around the gas nozzle 54. That is, nitrogen gas is discharged from the gas discharge port 542 in the horizontal direction to form an annular nitrogen gas flow. Further, on the lower side of the nitrogen gas flow, nitrogen gas is discharged from the gas discharge port 541 with a slight downward inclination from the horizontal direction, thereby forming a truncated conical nitrogen gas flow. This nitrogen gas discharged in the shape of a truncated cone flows toward the peripheral edge of the surface of the substrate W, corresponds to the horizontal N2 in the first embodiment, and functions as the "second gas" of the present invention.

As shown in FIGS. 14A and 14B, a central axis nozzle 60 is attached to the center of the nozzle body 540 configured in this way. The central axis nozzle 60 has a nozzle body 61 extending vertically along the rotation axis AX1. Five central piping portions (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 openings on the lower end side of the five central piping portions function as a chemical solution outlet 62a, a DIW outlet 63a, an IPA outlet 64a, a drying pretreatment liquid outlet 65a, and a central gas outlet 66a, respectively. Pipes 62b to 66b are connected to these discharge ports 62a to 66a, as in the first embodiment. Then, by controlling the opening and closing of the valves 62c to 66c by the control unit 4, the chemical liquid, DIW, IPA treatment liquid, drying pretreatment liquid, and nitrogen gas are selectively discharged toward the center of the surface of the substrate W. The nitrogen gas discharged vertically downward from the discharge port 66a, that is, the vertical N2, corresponds to an example of the "first gas" of the present invention.

A nozzle moving mechanism 55 is connected to the gas nozzle 54 to which the central axis nozzle 60 is integrally attached. The nozzle moving mechanism 55 includes a nozzle arm 551 that holds the gas nozzle 54, and a nozzle drive section 552 that moves the gas nozzle 54 in the vertical and horizontal directions by moving the nozzle arm 551. The nozzle drive unit 552 is, for example, a turning unit that horizontally moves the gas nozzle 54 around the nozzle rotation axis AX2 that extends vertically around the spin chuck 30 and the guard 73.

The nozzle moving mechanism 55 horizontally moves the gas nozzle 54 integrally with the central axis nozzle 60 between the upper center position (the position shown by the two-dot chain line in FIG. 13) and the standby position (the position shown by the solid line in FIG. 13). . The nozzle moving mechanism 55 further moves the gas nozzle 54 vertically between the upper center position and the lower center position. The standby position is a position where the gas nozzle 54 is located around the guard 73 in plan view. The upper center position and the lower center position are positions where the gas nozzle 54 overlaps the center of the substrate W in plan view (positions indicated by two-dot chain lines in FIG. 13). The upper center position is a position above the lower center position. When the nozzle moving mechanism 55 receives a lowering command from the control unit 4 and lowers the gas nozzle 54 from the upper center position to the lower center position, the lower surface of the gas nozzle 54 approaches the center of the surface of the substrate W.

When the gas nozzle 54 is arranged at the center position, the gas nozzle 54 overlaps the center of the surface of the substrate W in plan view. At this time, the lower surface of the gas nozzle 54 and the discharge ports 62a to 66a of the central axis nozzle 60 face the center of the upper surface of the substrate W. Then, the control unit 4 controls the motor (not shown) of the substrate rotation drive mechanism 34 to rotate the substrate W together with the spin base 32 while controlling the opening and closing of the valves 62c to 66c, as in the first embodiment. Perform a series of substrate processing. In particular, in the sublimation process (step S9), the control unit 4 opens the valve 66c to supply vertical N2 to the center of the surface of the substrate W as the "second gas" of the present invention. Further, when the control unit 4 opens the valves 544c and 546c, an annular nitrogen gas flow that radially spreads from the gas nozzle 54 is formed above the substrate W. When the valve 544c is opened, nitrogen gas is supplied from the gas discharge port 541 toward the peripheral edge of the surface of the substrate W as the "second gas" of the present invention.

In the processing unit 1B configured as described above, a series of substrate processing (steps S1 to S11) is executed in the flow shown in FIG. 7 in the same manner as in the first embodiment, but in particular, sublimation processing (step S9) is executed as follows.

FIG. 15 is a diagram showing the sublimation process performed in the fourth embodiment of the present invention. In the fourth embodiment, the sublimation process (step S9) is performed with the gas nozzle 54 positioned at the lower center position (the position indicated by the solid line in the lower schematic diagram of FIG. 15). At the start of this sublimation process, the control unit 4 closes the valve 66c to stop discharging vertical N2, while opening the valve 544c to start discharging horizontal N2 at a flow rate F2, as shown in the figure. As a result, while only the horizontal N2 is being supplied, fresh nitrogen gas that does not contain the sublimable substance SS is constantly supplied to the peripheral region SB2. As a result, at timing T41, for example, sublimation of the peripheral region SB2 progresses. On the other hand, since nitrogen gas is not supplied to the central region SB1 of the solidified body SB, sublimation of the central region SB1 is regulated. In this embodiment, the valve 546c is opened to form an annular nitrogen gas flow (broken line in the figure) above the horizontal N2, but the nitrogen gas flow may be omitted.

In this way, at the timing Tsw when the sublimation of the peripheral area SB2 has progressed preferentially or when the sublimation has been completed, the control unit 4 opens the valve 66c while keeping the valves 244c and 246c open to discharge vertical N2 at a flow rate F1 (<F2). Start. As a result, for example, as shown in the schematic diagram at timing T42 (lower right diagram in the figure), fresh nitrogen gas is supplied to the central region SB1, and the entire solidified body SB including the central region SB1 is Sublimation is progressing. Furthermore, fresh horizontal N2 continues to be supplied to the peripheral region SB2, and the concentration of the sublimable substance SS is kept low. Therefore, even if the sublimation of the peripheral area SB2 is not completed at the timing Tsw, the sublimation of the peripheral area SB2 continues. As a result, the entire coagulated body SB is reliably sublimated and removed by the sublimation process (step S9).

As described above, in the processing unit 1B using the gas nozzle 54, pattern collapse at the peripheral edge of the surface of the substrate W can be improved as in the first embodiment.

FIG. 16 is a diagram showing the configuration of a processing unit corresponding to the fifth embodiment of the substrate processing apparatus according to the present invention. FIG. 17 is a plan view of the device shown in FIG. 16. The processing unit 1C according to the fifth embodiment performs a series of substrate processing including sublimation processing as in the above embodiments without providing a structure (facing member 50 or gas nozzle 54) that protects the front surface Wf of the substrate W from above. conduct. In particular, the fifth embodiment differs greatly from the first embodiment in the nozzle configuration and the content of the sublimation process. The other configurations are the same as the first embodiment. Therefore, in the following, the differences will be mainly explained, and the same components will be given the same reference numerals and the explanation will be omitted.

The processing unit 1C includes a scan nozzle 57 to which a central axis nozzle 60 is integrally attached, and a nozzle moving mechanism 55 that moves the scan nozzle 57. Similar to the fourth embodiment, the nozzle moving mechanism 55 includes a nozzle arm 551 that holds the scan nozzle 57, and a nozzle drive section 552 that moves the scan nozzle 57 in the vertical and horizontal directions by moving the nozzle arm 551. It has The nozzle drive unit 552 is, for example, a turning unit that horizontally moves the scan nozzle 57 around the nozzle rotation axis AX2 that extends vertically around the spin chuck 30 and the guard 73.

The nozzle moving mechanism 55 moves through the center upper position (the position shown by the two-dot chain line in FIG. 17), and the first standby position (the position shown by the solid line in FIG. 17) and the second standby position (the one-dot chain line in FIG. 17). The scan nozzle 57 is horizontally moved integrally with the central axis nozzle 60 between the positions shown in FIG. Further, the nozzle moving mechanism 55 is capable of changing the moving speed of the scan nozzle 57 in accordance with a speed command from the control section 4. More specifically, as shown in FIG. 17, the nozzle moving mechanism 55 moves the scan nozzle 57 between a first standby position, a position P1 directly above the first substrate to a position P9 directly above the ninth substrate, and a second standby position. Speed can be changed. The nozzle moving mechanism 55 scans the scan nozzle 57 between the first standby position and the second standby position when performing the sublimation process (step S9), and also scans the scan nozzle 57 between the first standby position and the second standby position when performing the sublimation process (step S3), and the rinsing process (step S3). When performing step S4), replacement processing (step S5), pre-drying liquid supply processing (step S6), film thickness reduction processing (step S7), and coagulation formation processing (step S8), the scan nozzle 57 is placed above the center. position (position P5 directly above the fifth board). Here, in the coagulum formation process, the scan nozzle 57 may be scanned from the upper center position to the first standby position or the second standby position.

A central axis nozzle 60 is attached to the center of the scan nozzle 57, as shown in FIG. The central axis nozzle 60 has a nozzle body 61 extending vertically along the rotation axis AX1. Five central piping 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 main body 61, as in the first embodiment. Furthermore, pipes 62b to 66b are connected to these five central pipe sections. In the center positioning state in which the scan nozzle 57 is positioned at the upper center position (position P5 directly above the fifth substrate), the control unit 4 controls the opening and closing of the valves 62c to 66c to remove the chemical liquid, DIW, IPA processing liquid before drying. The processing liquid and nitrogen gas are selectively discharged toward the center of the surface of the substrate W. The nitrogen gas discharged from the central axis nozzle 60 in this centrally positioned state corresponds to an example of the "first gas" of the present invention. Further, while the scan nozzle 57 is located at the position P1 directly above the first substrate or the position P9 directly above the ninth substrate, the nitrogen gas discharged from the central gas discharge port 66a of the central axis nozzle 60 is the "second gas" of the present invention. This corresponds to an example. In this embodiment, the central gas discharge port 66a functions as a "first discharge part" and a "second discharge part" of the present invention.

In the processing unit 1C configured in this way, a series of substrate processing (steps S1 to S11) is executed in the flow shown in FIG. 7 in the same manner as in the first embodiment, but in particular, sublimation processing (step S9) is executed as follows. The control unit 4 moves the scan nozzle 57 to a position P1 directly above the first substrate (or a position P9 directly above the ninth substrate), that is, above the peripheral edge of the surface of the substrate W. Further, as the scan nozzle 57 descends at the peripheral edge of the surface of the substrate W, the lower surface of the scan nozzle 57 approaches the peripheral edge of the surface of the substrate W. Subsequently, the control unit 4 opens the valve 66c, so that nitrogen gas is supplied to the peripheral edge of the surface of the substrate W from the central axis nozzle 60 held by the scan nozzle 57. As a result, nitrogen gas is first supplied to the peripheral region SB2 of the solidified body SB, and sublimation of the peripheral region SB2 is started. Then, at the timing when the sublimation of the peripheral region SB2 has progressed preferentially or when the sublimation has been completed, the control unit 4 controls the scan nozzle 57 to move the scan nozzle 57 toward the substrate W while continuing to discharge nitrogen gas from the central axis nozzle 60. Move it sequentially toward the upper part of the center of the surface. By locating the scan nozzle 57 at the upper center position (position P5 directly above the fifth substrate), nitrogen gas is supplied from the central axis nozzle 60 to the center of the surface of the substrate W. As a result, sublimation of the central region SB1 of the solidified body SB is finally started. In this embodiment, the control unit 4 positions the scan nozzle 57 at the upper center position for a predetermined period of time, and then returns the scan nozzle 57 to the standby position via above the peripheral edge of the surface of the substrate W. Further, during the above movement, the control unit 4 moves the lower surface of the scan nozzle 57 away from the surface Wf of the substrate W by raising the scan nozzle 57, and closes the valve 66c to stop the discharge of nitrogen gas from the central axis nozzle 60. do.

As described above, in the fifth embodiment as well, pattern collapse at the peripheral edge of the surface of the substrate W can be improved as in the first embodiment.

Note that the present invention is not limited to the embodiments described above, and various changes other than those described above can be made without departing from the spirit thereof. For example, in the first embodiment, the second embodiment, the fourth embodiment, and the fifth embodiment, the timing Tsw at which the sublimation of the peripheral area SB2 progresses preferentially or is completed is defined as the elapsed time from the start of the sublimation process. Although it is managed based on time, it may also be managed based on other indicators. For example, the timing Tsw may be determined based on the detected values of the flowmeters 81 to 83, that is, the flow rate values. That is, the viscosity tends to increase as the amount of gas containing the sublimable substance increases. On the other hand, when the sublimation of the peripheral region SB2 of the solidified body SB is completed, the concentration of the gaseous sublimable substance in the semi-closed space SP, the recovery space surrounded by the exhaust tub 70, or the exhaust path becomes low. In other words, the internal space 21 of the chamber 20 and the exhaust path exhausted from the internal space 21 approach an atmosphere in which only nitrogen gas exists, and the flow rate of gas flowing through the internal space 21 and the exhaust path increases. Therefore, the timing Tsw may be determined based on the fact that the measured values by the flowmeters 81 to 83 change beyond a predetermined threshold value. Further, the timing Tsw may be determined based on a change in the differential value of the measured value.

Furthermore, a sublimable substance detection sensor that detects the content of the sublimable substance may be used instead of the flow meter. Further, in the fourth embodiment or the fifth embodiment, the sublimable substance detection sensor may be attached to the outer peripheral surface of the gas nozzle 54 or the scan nozzle 57 to detect the sublimable substance in the atmosphere around the nozzle. That is, the timing Tsw may be determined based on a change in the detected value (content) by the sublimable substance detection sensor to a predetermined threshold value or less. Further, the timing Tsw may be determined based on one of the output values of a plurality of flowmeters or sublimable substance detection sensors, or the timing Tsw may be determined by comprehensively verifying them.

INDUSTRIAL APPLICABILITY The present invention can be applied to all substrate processing techniques in which a gas is supplied to a coagulated body made of a sublimable substance that changes into a gas without passing through a liquid state, thereby sublimating the coagulated body and drying the substrate. .

1A, 1B, 1C...processing unit (substrate processing equipment)
4...Control part 20...Chamber 21...Internal space 66a...Central gas discharge port (first discharge part, second discharge part)
67...Peripheral gas discharge port (second discharge part)
81-83...Flowmeter 541,542...Gas discharge port (second discharge part)
AX1...Rotation axis (of the coagulated body) PT...Pattern S9...Sublimation treatment SB...Coagulated body SB1...Central region (of the coagulated body) SS...Sublimable substance W...Substrate Wf...Surface (of the substrate)

Claims (9)

A substrate processing method in which a coagulated substance containing a sublimable substance that changes into a gas without passing through a liquid is formed on the entire surface of a substrate, and the substrate is dried by sublimating the coagulated substance, the method comprising:
A first sublimation step of discharging a first gas toward the center of the surface of the substrate to flow the first gas around the substrate via the entire solidified body to sublimate the entire solidified body. and,
Discharging a second gas toward the surface periphery of the substrate and causing the second gas to flow around the substrate via a periphery region on the surface periphery of the solidified body, thereby spreading the second gas toward the surface periphery of the substrate. A second sublimation step of sublimating,
A substrate processing method characterized in that the second sublimation step starts earlier than the first sublimation step, or the flow rate of the second gas is higher than the flow rate of the first gas. The substrate processing method according to claim 1,
A substrate processing method, wherein after the start of the second sublimation step, the first sublimation step is started while continuing to discharge the second gas. 3. The substrate processing method according to claim 2,
The flow rate of the first gas after the start of the first sublimation step is a first flow rate,
The substrate processing method, wherein the flow rate of the second gas is a second flow rate higher than the first flow rate. 3. The substrate processing method according to claim 2,
From the start of the first sublimation step,
A substrate processing method, wherein the flow rate of the first gas increases over time, while the flow rate of the second gas decreases over time. The substrate processing method according to claim 1,
The first sublimation step is started at the same time as the second sublimation step or after the start of the second sublimation step,
The substrate processing method, wherein the flow rate of the second gas is a second flow rate higher than the flow rate of the first gas. The substrate processing method according to claim 1,
A substrate processing method, wherein the first sublimation step is performed after the second sublimation step. The substrate processing method according to claim 2, 3, 4 or 6,
evacuating an internal space of a chamber in which the first sublimation step and the second sublimation step are performed;
a step of measuring a flow rate value of at least one of a gas component existing in the internal space and a gas component exhausted from the internal space,
A substrate processing method, wherein the timing to start the first sublimation step is determined based on the flow rate value. The substrate processing method according to claim 2, 3, 4 or 6,
evacuating an internal space of a chamber in which the first sublimation step and the second sublimation step are performed;
a step of detecting at least one of a gaseous sublimable substance existing in the internal space and a gaseous sublimable substance exhausted from the internal space with a sublimable substance detection sensor,
A substrate processing method, wherein a timing for starting the first sublimation step is determined based on a detection value of the sublimable substance detection sensor. A substrate processing apparatus that sublimates a coagulated substance from a substrate on which a coagulated substance containing a sublimable substance that changes into a gas without passing through a liquid and dries the substrate, the substrate processing apparatus comprising:
a first discharge part that discharges a first gas toward the center of the surface of the substrate;
a second discharge part that discharges a second gas toward the peripheral edge of the surface of the substrate;
The first gas is discharged from the first discharge section to flow around the substrate via the entire solidified body to sublimate the entire solidified body, and the second discharge section a control unit that discharges the second gas from the solidified body and causes the second gas to flow around the substrate via a peripheral region on the surface peripheral portion of the solidified body to sublimate the peripheral region; Prepare,
The control unit performs at least one of a discharge timing control that causes the discharge start of the second gas to be earlier than a discharge start of the first gas, and a flow rate control that increases the flow rate of the second gas than the flow rate of the first gas. A substrate processing apparatus characterized by:

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