Substrate processing method and substrate processing system

Abstract

To reduce the amount of liquid adhering to the underside of a substrate before it is brought into the chamber in substrate processing technology that uses supercritical processing fluid in a chamber to process the substrate.SOLUTION: A substrate processing method of the present invention comprises a process in which a wet processing apparatus forms a liquid film on a top surface of a substrate, a process in which a conveying apparatus carries the substrate on which the liquid film is formed into a chamber of a supercritical processing apparatus, and a process in which a supercritical processing apparatus treats the substrate in the chamber with supercritical processing fluid. After the liquid film is formed on the substrate and during at least a part of the period of time when the substrate is outside the chamber, there is a further process in which a gas discharge unit blows gas toward a lower surface of the substrate supported in a horizontal position.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This invention relates to a substrate processing technology for processing a substrate using a processing fluid in a supercritical state within a processing vessel.

Background Art

[0002] In the processing steps of various substrates such as semiconductor substrates and glass substrates for display devices, there are those that process the substrate with various processing fluids. Such processing may be performed within an airtight processing vessel for the purpose of efficient use of the processing fluid and prevention of dissipation to the outside. For example, in the processing apparatus described in Patent Document 1, a substrate to be processed is carried into the internal space of a chamber having an opening on the side surface and placed on a flat support tray integrated with a lid portion, and the internal space is sealed by closing the opening with the lid portion. From this state, a processing fluid in a supercritical state is introduced and the substrate is processed. Since the internal space of the chamber is formed slightly larger than the envelope outer shape of the substrate and the support tray, it is possible to reduce the amount of processing fluid used and improve the processing efficiency.

[0003] In this type of technology, in order to avoid the substrate before processing from being exposed to air or to prevent the collapse of the fine patterns formed on the substrate surface, the substrate may be carried into the chamber in a state where a liquid is accumulated on its surface. Also in the above prior art, the substrate being carried in is covered with a liquid film of an organic solvent, for example, IPA (isopropyl alcohol), after the cleaning process.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The liquid that forms such a film contributes to protecting the substrate surface during transport, but it should be removed as soon as possible during the subsequent supercritical fluid treatment. However, when substrates are transported while placed on a support tray, as in the conventional technology described above, the liquid that gets into the tiny gap between the bottom of the substrate and the support tray is particularly difficult to remove. This can lead to problems such as the time required for treatment to completely remove the liquid being prolonged, or poor treatment results due to the liquid remaining for a long time.

[0006] Therefore, it is preferable that the underside of the substrate being fed into the chamber be as free of liquid as possible. However, it is difficult to completely prevent liquid from seeping to the underside between the formation of the liquid film and the time the substrate is fed into the chamber. Consequently, it is necessary to remove as much liquid as possible from the underside of the substrate before it is fed into the chamber. The above-mentioned conventional technology, which does not take such measures, had room for improvement in this respect.

[0007] This invention has been made in view of the above problems, and aims to reduce the amount of liquid adhering to the underside of a substrate before it is introduced into the chamber, in a substrate processing technology that processes a substrate using a supercritical processing fluid in a chamber. [Means for solving the problem]

[0008] One aspect of this invention is a substrate processing method comprising the steps of: a wet processing apparatus forming a liquid film on the upper surface of a substrate; a transport apparatus transporting the substrate on which the liquid film has been formed into the chamber of a supercritical processing apparatus; and the supercritical processing apparatus processing the substrate in the chamber with a supercritical processing fluid. This substrate processing method further comprises the step of, after the liquid film has been formed on the substrate and for at least a portion of the time while the substrate is outside the chamber, a gas discharge unit blowing gas toward the lower surface of the substrate which is supported in a horizontal position. The transport device is provided with a hand that supports the substrate from below, and the gas discharge unit has a nozzle provided on the hand toward the substrate, and the nozzle discharges the gas horizontally from one end to the other of the lower surface of the substrate. ru.

[0009] In this configuration, after the formation of the liquid film, gas is blown onto the underside of the substrate while the substrate is outside the chamber. This blows away and removes any liquid adhering to the underside of the substrate. As a result, the amount of liquid brought into the chamber when the substrate is placed inside the chamber can be reduced, and in particular, the amount of liquid that remains adhering to the underside of the substrate can be significantly reduced. [Effects of the Invention]

[0010] As described above, in this invention, by first introducing pressurized gas to the underside of the support tray, which houses the substrate together with the support tray in the chamber, liquid adhering to the underside of the substrate can be flushed away. Therefore, the time required to remove residual liquid in the subsequent supercritical fluid treatment can be shortened, and treatment defects caused by residual liquid can be suppressed. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows a schematic configuration of a substrate processing system to which the present invention can be applied. [Figure 2] This flowchart shows an overview of the processing in this circuit board processing system. [Figure 3] This figure shows an example of the configuration of a wet processing apparatus. [Figure 4] This diagram schematically illustrates the operation flow of a wet processing apparatus. [Figure 5] This is a side view showing the configuration of a supercritical fluid processing apparatus. [Figure 6] This diagram schematically illustrates the process of transferring circuit boards. [Figure 7] This figure shows a first embodiment for performing gas blowing. [Figure 8] This figure shows a second embodiment for performing gas blowing. [Figure 9] This figure shows a third embodiment for performing gas blowing. [Modes for carrying out the invention]

[0012] <System Configuration> Figure 1 shows a schematic configuration of a substrate processing system to which the present invention can be applied. To consistently indicate directions in the following figures, an XYZ Cartesian coordinate system is set up as shown in Figure 1. Here, the XY plane corresponds to the horizontal plane, and the Z direction corresponds to the vertical direction. More specifically, the (-Z) direction represents the vertically downward direction.

[0013] This substrate processing system 1 is a processing system for wetting various substrates, such as semiconductor wafers, by supplying a processing liquid to the upper surface of the substrate, and then drying the substrate. It has a system configuration suitable for implementing the substrate processing method according to the present invention. Specifically, the substrate processing apparatus 1 comprises, as its main components, a wet processing apparatus 2, a transport apparatus 3, a supercritical processing apparatus 4, and a control unit 9.

[0014] The wet processing apparatus 2, the transport apparatus 3, and the supercritical processing apparatus 4 are arranged in this order along the (+X) direction. The main part of the wet processing apparatus 2 is housed inside the processing chamber 200, and an opening (not shown) for loading and unloading substrates is provided on the (+X) side of the processing chamber 200, and a shutter 201 that can be opened and closed is provided over this opening. On the other hand, the main part of the supercritical processing apparatus 4 is housed inside the processing chamber 400, and an opening (not shown) for loading and unloading substrates is provided on the (-X) side of the processing chamber 400, and a shutter 401 that can be opened and closed is provided over this opening.

[0015] The wet processing apparatus 2 receives the substrate to be processed and performs a predetermined wet processing. The content of the processing is not particularly limited. The transport apparatus 3 unloads the substrate after wet processing from the wet processing apparatus 2 and transports it to the supercritical processing apparatus 4. The supercritical processing apparatus 4 performs a drying process (supercritical drying process) on the transported substrate using a processing fluid in a supercritical state. These are installed in a clean room. Therefore, the transport apparatus 3 transports the substrate S in an air atmosphere and under atmospheric pressure.

[0016] The control unit 9 controls the operations of these respective devices to implement a predetermined process. For this purpose, the control unit 9 includes a CPU 91, a memory 92, a storage 93, an interface 94, and the like. The CPU 91 executes various control programs. The memory 92 temporarily stores processing data. The storage 93 stores the control programs executed by the CPU 91. The interface 94 exchanges information with a user or an external device. The operations of the devices to be described later are realized by the CPU 91 executing the control programs pre-written in the storage 93 and causing each part of the devices to perform a predetermined operation.

[0017] By the CPU 91 executing a predetermined control program, functional blocks such as a wet process control unit 95 that controls the operation of the wet processing apparatus 2, a conveyance control unit 96 that controls the operation of the conveyance apparatus 3, and a supercritical process control unit 97 that controls the operation of the supercritical processing apparatus 4 are realized software-wise in the control unit 9. Note that at least a part of each of these functional blocks may be constituted by dedicated hardware.

[0018] As the "substrate" in the present embodiment, various substrates such as 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 a FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, and a substrate for a magneto-optical disk can be applied. Hereinafter, a substrate processing apparatus mainly used for processing a disk-shaped semiconductor wafer will be taken as an example and described with reference to the drawings. However, it can be similarly applied to the processing of the various substrates exemplified above. Also, various shapes of the substrate can be applied.

[0019] Figure 2 is a flowchart outlining the processes performed by this substrate processing system. This substrate processing system 1 receives the substrate S to be processed and sequentially performs wet processing using a processing liquid and supercritical drying processing using a supercritical processing fluid. Specifically, it is as follows: The substrate S to be processed is placed in the wet processing apparatus 2 that constitutes the substrate processing system 1 (step S101). The substrate S may be brought in directly by an external transport device, or it may be brought in via a transport device 3 from an external transport means.

[0020] The wet processing apparatus 2 performs a wet treatment on the substrate S using a predetermined processing liquid (step S102). Subsequently, a liquid film formation treatment is performed in which a liquid film is formed on the surface using an organic solvent such as IPA (step S103). For example, if a fine pattern is formed on the surface of the substrate S, the surface tension of the liquid remaining on the substrate S may cause the pattern to collapse. Also, incomplete drying may leave watermarks on the surface of the substrate S. Furthermore, exposure of the substrate S surface to the outside air may cause deterioration such as oxidation. To prevent such problems, the substrate S may be transported with its surface (pattern-forming surface) covered with liquid.

[0021] For example, if the cleaning solution is mainly water, the transport is carried out with a liquid film formed using an organic solvent such as IPA or acetone, which has a lower surface tension and is less corrosive to the substrate. That is, the substrate S is supported in a horizontal position and with a liquid film formed on its upper surface, and is transported out of the wet treatment apparatus 2 by the transport device 3 (step S104), and is further transported and finally brought into the supercritical treatment apparatus 4 (step S105).

[0022] The supercritical processing apparatus 4 performs supercritical drying on the transported substrate S (step S106). The processing fluid in the supercritical state has extremely low surface tension and high fluidity. Therefore, it penetrates into the interior of the fine patterns formed on the surface of the substrate S and replaces the liquid inside the patterns. For example, when carbon dioxide is used as the supercritical processing fluid, it dissolves organic solvents well, so the liquid that had formed a liquid film can be efficiently replaced and removed from the substrate surface.

[0023] The supercritical fluid is vaporized and discharged without passing through a liquid phase. The liquid adhering to the substrate S is replaced and discharged by the supercritical fluid, and the processing fluid is also discharged, resulting in a dry substrate S. Since no gas-liquid interface is formed in this process, pattern collapse due to surface tension can be avoided. After processing, the substrate S is transported out of the supercritical processing apparatus 4 by the transport device 3 and handed over to the next process. The content of the next process is arbitrary.

[0024] The structure of each component of the substrate processing system 1 for performing the series of processes described above will be explained in more detail.

[0025] The transport device 3 is equipped with a transport robot 30, which has a hand 31 at the end of an extendable and rotatable arm (not shown in the figure). As indicated by the dashed arrow, the transport robot 30 is rotatable around the Z axis. The hand 31 can support the substrate by partially contacting the underside of the substrate. As shown by the dotted line in Figure 1, the hand 31 is housed inside the cover 32 and can move forward and backward relative to both the wet processing apparatus 2 and the supercritical apparatus 4 by extending out of the cover 32 as needed. This allows for the loading and unloading of substrates to and from the wet processing apparatus 2 and the supercritical apparatus 4, respectively. The operation of the transport robot 30 is controlled by the transport control unit 96 of the control unit 9.

[0026] As this type of transport robot, the one described in Japanese Patent Publication No. 2020-188228, previously disclosed by the applicant, is suitably applicable. The specific structure of the transport robot 31 can be found in that publication, so a detailed explanation is omitted here.

[0027] Figure 3 shows an example of the configuration of a wet processing apparatus. More specifically, Figure 3 is a side view showing the overall configuration of the wet processing apparatus 2. This wet processing apparatus 2 is a device that processes a substrate by supplying a processing liquid to the upper surface of the substrate. The operation of the wet processing apparatus 2 is controlled by the wet processing control unit 95 of the control unit 9.

[0028] The wet processing apparatus 2 supplies a processing liquid to the upper surface of the substrate S to perform wet processing such as surface treatment and cleaning of the substrate S. For this purpose, the wet processing apparatus 2 is equipped with a substrate holding section 21, a splash guard 22, and processing liquid supply sections 23 and 24 inside the processing chamber 200. The operation of these is controlled by a wet processing control section 95 provided in the control section 9.

[0029] The substrate holding section 21 has a disc-shaped spin chuck 211 having a diameter approximately the same as that of the substrate S, and a plurality of chuck pins 212 are provided on the periphery of the spin chuck 211. The chuck pins 212 contact the periphery of the substrate S and support the substrate S, so that the spin chuck 211 can hold the substrate S in a horizontal position while being spaced apart from its upper surface.

[0030] The spin chuck 211 is supported by a rotating support shaft 213 extending downward from the center of its lower surface, so that its upper surface is horizontal. The rotating support shaft 213 is rotatably supported by a rotating mechanism 214 attached to the bottom of the processing chamber 200. The rotating mechanism 214 incorporates a rotating motor (not shown), and when the rotating motor rotates in response to a control command from the control unit 9, the spin chuck 211, which is directly connected to the rotating support shaft 213, rotates around the vertical axis shown by the dashed line. In Figure 2, the up and down direction is the vertical direction. As a result, the substrate S is rotated around the vertical axis while remaining in a horizontal position.

[0031] A splash guard 22 is provided so as to surround the substrate holding portion 21 from the side. The splash guard 22 has a roughly cylindrical cup 221 provided so as to cover the periphery of the spin chuck 211, and a liquid receiving portion 222 provided below the outer circumference of the cup 221. The cup 221 moves up and down in response to a control command from the control unit 9. The cup 221 moves up and down between a lower position where the upper end of the cup 221 is below the periphery of the substrate S held by the spin chuck 211, as shown by the solid line in Figure 3, and an upper position where the upper end of the cup 221 is above the periphery of the substrate S, as shown by the dotted line in Figure 3.

[0032] As shown by the solid line in Figure 3, when the cup 221 is in the lower position, the substrate S held by the spin chuck 211 is exposed to the outside of the cup 221. This prevents the cup 221 from becoming an obstacle when loading or unloading the substrate S into or out of the spin chuck 211.

[0033] Furthermore, as shown by the dotted line in Figure 3, when the cup 221 is in the upper position, it surrounds the periphery of the substrate S held by the spin chuck 211. This prevents the processing liquid that is shaken off the periphery of the substrate S during liquid supply (described later) from scattering into the chamber 200, and ensures reliable collection of the processing liquid. In other words, as the substrate S rotates, droplets of processing liquid shaken off the periphery of the substrate S adhere to the inner wall of the cup 221 and flow downward, where they are collected by the liquid receiving section 222 located below the cup 221. Multiple cups may be arranged concentrically to collect multiple processing liquids individually.

[0034] The processing liquid supply unit 23 has a structure in which a nozzle 234 is attached to the tip of an arm 233 that extends horizontally from a pivot shaft 232 rotatably mounted on a base 231 fixed to the processing chamber 200. When the pivot shaft 232 rotates in response to a control command from the control unit 9, the arm 233 swings, and the nozzle 234 at the tip of the arm 233 moves between a retracted position, which is moved to the side from above the substrate S, and a processing position above the substrate S.

[0035] The nozzle 234 is connected to a processing liquid supply source 238. When an appropriate processing liquid is supplied from the processing liquid supply source 238, the processing liquid is discharged from the nozzle 234 toward the substrate S. The spin chuck 211 rotates at a relatively low speed, rotating the substrate S. By supplying the processing liquid from the nozzle 234, which is positioned above the center of rotation of the substrate S, the upper surface Sa of the substrate S is treated with the processing liquid. Various liquids with different functions, such as developer, etching solution, cleaning solution, and rinsing solution, can be used as the processing liquid, and their composition is arbitrary. In addition, a combination of multiple types of processing liquids may be used to perform the treatment.

[0036] The other processing liquid supply unit 24 also has a configuration corresponding to the first processing liquid supply unit 23 described above. That is, the second processing liquid supply unit 24 has a base 241, a pivot shaft 242, an arm 243, a nozzle 244, etc., and these configurations are equivalent to those of the first processing liquid supply unit 23. The pivot shaft 242 rotates in response to a control command from the control unit 9, causing the arm 243 to swing. The nozzle 244 at the tip of the arm 243 supplies processing liquid to the upper surface Sa of the substrate S.

[0037] In this wet processing apparatus 2, the second processing liquid supply unit 24 is used to form a liquid film on the substrate S after wet processing to prevent drying. That is, the substrate S after wet processing is transported to the supercritical processing apparatus 4 to undergo supercritical drying processing, but in order to prevent the surface of the substrate S from being exposed and oxidized during transport, or for the fine patterns formed on the surface to collapse, the substrate S is transported with its surface covered with a paddle-shaped liquid film.

[0038] The liquid that constitutes the liquid film is a substance with a lower surface tension than water, which is the main component of the treatment solution used in the cleaning process, such as an organic solvent like isopropyl alcohol (IPA) or acetone.

[0039] Here, the wet processing apparatus 2 is provided with two sets of processing liquid supply units, but the number of processing liquid supply units, their structure, and function are not limited to this. For example, there may be only one set of processing liquid supply units, or there may be three or more sets. Also, one processing liquid supply unit may be equipped with multiple nozzles. For example, multiple nozzles may be provided at the tip of one arm. Furthermore, in addition to the mode in which the processing liquid is discharged with the nozzles positioned in a predetermined position as described above, a mode in which the processing liquid is discharged while the nozzles scan and move along the upper surface Sa of the substrate S may also be included. In addition, a gas supply unit having a nozzle for discharging gas may be further provided. Also, at least one of the multiple nozzles provided in the processing liquid supply unit may discharge gas.

[0040] Figure 4 is a schematic diagram showing the operation flow of the wet processing apparatus. In Figure 4, the dashed arrows indicate the direction of movement of each part. As shown in Figure 4(a), with the cup 221 in the lower position, the shutter 201 (Figure 3) of the processing chamber 200 is opened, and the unprocessed substrate S supported by the hand 31 of the transport device 3 is brought in. After the substrate S is transferred to the chuck pin 212 provided on the upper peripheral edge of the spin chuck 211, the hand 31 retracts and the shutter 201 is closed.

[0041] In the example of wet processing using nozzle 234, as shown in Figure 4(b), the cup 221 rises and is positioned in an upper position, and the nozzle 234 moves toward the rotation center of the substrate S, indicated by the dashed line. Then, as shown in Figure 4(c), with the nozzle 234 positioned toward the rotation center of the substrate S, the substrate S is rotated at a predetermined rotational speed, and the processing liquid L1 is discharged from nozzle 234. The processing liquid L1 flows outward along the upper surface of the substrate S due to centrifugal force and is eventually shaken off from the periphery of the substrate S. The shaken-off liquid is collected by cup 221.

[0042] Furthermore, a liquid film formation process (step S103) is performed before the substrate S is unloaded. Specifically, a nozzle 244 for liquid film formation is positioned at the rotation center of the substrate S, and a liquid film formation solution, such as IPA, is discharged from the nozzle 244. As a result, the upper surface Sa of the substrate S is covered with a liquid film LP. The thickness of the liquid film can be adjusted by the rotation speed of the substrate S.

[0043] After the supply of the processing liquid and the rotation of the substrate S are stopped, the substrate S with the liquid film LP formed on it is discharged. That is, the cup 221 descends to a lower position, and the hand 31 of the transport robot 30 discharges the substrate S while it is in a horizontal position. The substrate S, along with the liquid film LP, is transported to the supercritical treatment apparatus 4.

[0044] Figure 5 is a side view showing the configuration of the supercritical fluid processing apparatus. The supercritical fluid processing apparatus 4 is a device that performs a drying treatment on a substrate S after wet processing using a processing fluid in a supercritical state. More specifically, the supercritical fluid processing apparatus 4 is a device that receives the substrate S after wet processing, replaces the liquid remaining in the substrate S with a processing fluid in a supercritical state, and then discharges the processing fluid to ultimately dry the substrate S.

[0045] The supercritical processing apparatus 4 comprises a processing unit 41 and a transfer unit 43 located within a processing chamber 400, and a supply unit 45. The processing unit 41 is the main component for performing the supercritical drying process. The transfer unit 43 receives the wet-processed substrate S transported by the transport device 3 and loads it into the processing unit 41, and also transfers the processed substrate S from the processing unit 41 to an external transport device. The supply unit 45 supplies the chemical substances, power, and energy necessary for the process to the processing unit 41 and the transfer unit 43. These operations are controlled by the control unit 9, particularly the supercritical processing control unit 97.

[0046] The processing unit 41 has a structure in which a processing chamber 412 is mounted on a base 411. The processing chamber 412 is composed of a combination of several metal blocks, and its interior is hollow, forming a processing space SP. The substrate S to be processed is brought into the processing space SP and processed. A slit-shaped opening 421 extending elongated in the X direction is formed on the (-Y) side of the processing chamber 412. The processing space SP and the external space are in communication through the opening 421. The cross-sectional shape of the processing space SP is generally the same as the opening shape of the opening 421. That is, the processing space SP has a cross-sectional shape that is long in the X direction and short in the Z direction, and is a cavity extending in the Y direction.

[0047] A lid member 413 is provided on the (-Y) side of the processing chamber 412 so as to close the opening 421. By closing the opening 421 of the processing chamber 412 with the lid member 413, an airtight processing container is formed. This makes it possible to process the substrate S under high pressure in the internal processing space SP. A flat support tray 415 is mounted horizontally on the (+Y) side of the lid member 413. The upper surface of the support tray 415 is a support surface on which the substrate S can be placed. The lid member 413 is supported so as to be able to move horizontally in the Y direction by a support mechanism (not shown).

[0048] The lid member 413 is movable forward and backward relative to the processing chamber 412 by a forward / backward mechanism 453 provided on the supply unit 45. Specifically, the forward / backward mechanism 453 has a linear motion mechanism such as a linear motor, linear guide, ball screw mechanism, solenoid, or air cylinder. Such a linear motion mechanism moves the lid member 413 in the Y direction. The forward / backward mechanism 453 operates in response to control commands from the control unit 9.

[0049] As the lid member 413 moves in the (-Y) direction, it separates from the processing chamber 412, and as shown by the dotted line, the support tray 415 is pulled out of the processing space SP through the opening 421, making the support tray 415 accessible. That is, it becomes possible to place a substrate S on the support tray 415 and to remove a substrate S that is placed on the support tray 415. On the other hand, as the lid member 413 moves in the (+Y) direction, the support tray 415 is housed inside the processing space SP. If a substrate S is placed on the support tray 415, the substrate S is transported into the processing space SP together with the support tray 415.

[0050] The lid member 413 moves in the (+Y) direction and closes the opening 421, thereby sealing the processing space SP. A sealing member 422 is provided between the (+Y) side surface of the lid member 413 and the (-Y) side surface of the processing chamber 412, maintaining the airtight state of the processing space SP. The sealing member 422 is made of rubber, for example. In addition, the lid member 413 is fixed to the processing chamber 412 by a locking mechanism (not shown). In this way, the lid member 413 can be switched between a closed state (solid line) in which the opening 421 is closed and the processing space SP is sealed, and a separated state (dotted line) in which it is far enough away from the opening 421 that the substrate S can be inserted and removed.

[0051] With the processing space SP airtight, processing of the substrate S is performed within the processing space SP. In this embodiment, a fluid supply unit 457 provided in the supply unit 45 delivers a processing fluid of a substance usable for supercritical processing, such as carbon dioxide, as the processing fluid, and further pressurizes the processing fluid in the processing chamber 412 to bring it to a supercritical state. The processing fluid is supplied to the processing unit 41 in gaseous or liquid form. Carbon dioxide is a suitable chemical substance for supercritical drying processing because it becomes supercritical at relatively low temperatures and low pressures, and has the property of dissolving organic solvents, which are frequently used in substrate processing, well. The critical point at which carbon dioxide becomes supercritical is a pressure (critical pressure) of 7.38 MPa and a temperature (critical temperature) of 31.1°C.

[0052] When the processing fluid is filled into the processing space SP and the processing space SP reaches an appropriate temperature and pressure, the processing space SP is filled with the processing fluid in a supercritical state. In this way, the substrate S is processed by the supercritical fluid in the processing chamber 412. The supply unit 45 is provided with a fluid recovery unit 455, and the fluid after processing is recovered by the fluid recovery unit 455. The fluid supply unit 457 and the fluid recovery unit 455 are controlled by the supercritical processing control unit 97.

[0053] The processing space SP has a shape and volume that can accommodate the support tray 415 and the substrate S supported therein. Specifically, the processing space SP has a roughly rectangular cross-sectional shape that is wider horizontally than the width of the support tray 415 and greater vertically than the combined height of the support tray 415 and the substrate S, and has a depth that can accommodate the support tray 415. Thus, the processing space SP has a shape and volume that can accommodate the support tray 415 and the substrate S. However, the gap between the support tray 415 and the substrate S and the inner wall surface of the processing space SP is small. Therefore, the amount of processing fluid required to fill the processing space SP is relatively small.

[0054] The fluid supply unit 457 supplies processing fluid to the processing space SP further to the (+Y) side than the (+Y) side end of the substrate S. On the other hand, the fluid recovery unit 55 discharges the processing fluid that has flowed through the space above the substrate S and the space below the support tray 415 within the processing space SP, further to the (-Y) side than the (-Y) side end of the substrate S. As a result, a laminar flow of processing fluid is formed within the processing space SP, both above the substrate S and below the support tray 415, moving from the (+Y) side to the (-Y) side.

[0055] The supercritical fluid processing control unit 97 of the control unit 9 determines the pressure and temperature in the processing space SP based on the detection results of a detection unit (not shown), and controls the fluid supply unit 457 and the fluid recovery unit 455 based on these results. This ensures that the supply of processing fluid to the processing space SP and the discharge of processing fluid from the processing space SP are appropriately managed, and the pressure and temperature in the processing space SP are adjusted according to a predetermined processing recipe.

[0056] The transfer unit 43 is responsible for transferring the substrate S between the transport mechanism 3 and the support tray 415. For this purpose, the transfer unit 43 comprises a main body 431, a lifting member 433, a base member 435, and a plurality of lift pins 437. The lifting member 433 is a columnar member extending in the Z direction and is supported by a support mechanism (not shown) so as to be movable in the Z direction relative to the main body 431. A base member 435 having a substantially horizontal upper surface is attached to the upper part of the lifting member 433. A plurality of lift pins 437 are erected upward from the upper surface of the base member 435. Each of the lift pins 437 supports the substrate S in a horizontal position from below by its upper end contacting the lower surface of the substrate S. In order to stably support the substrate S in a horizontal position, it is desirable to provide three or more lift pins 437 whose upper end heights are equal to each other.

[0057] The lifting member 433 is movable up and down by a lifting mechanism 451 provided in the supply unit 45. Specifically, the lifting mechanism 451 has a linear motion mechanism such as a linear motor, linear guide, ball screw mechanism, solenoid, or air cylinder, and such a linear motion mechanism moves the lifting member 433 in the Z direction. The lifting mechanism 451 operates in response to control commands from the control unit 9.

[0058] The base member 435 moves up and down as the lifting member 433 moves up and down, and multiple lift pins 437 move up and down in conjunction with it. This enables the transfer of the substrate S between the transfer unit 43 and the support tray 415. More specifically, as shown by the dotted line in Figure 3, the substrate S is transferred when the support tray 415 is pulled out of the chamber. For this purpose, the support tray 415 is provided with through holes 417 for inserting the lift pins 437. When the base member 435 rises, the upper ends of the lift pins 437 reach above the upper surface of the support tray 415 through the through holes 417. In this state, the substrate S being transported by the transport robot 30 is transferred from the hand 31 of the transport robot 30 to the lift pins 437. As the lift pins 437 descend, the substrate S is transferred from the lift pins 437 to the support tray 415. The substrate S can be unloaded by the reverse procedure described above.

[0059] Figure 6 schematically shows the process of transferring a substrate. Referring to Figures 6(a) to 6(d), the operation of each part in the transfer of the substrate S will be explained. The initial state of the device is shown in Figure 5. From this state, when receiving a substrate S brought in from the outside, as shown in Figure 6(a), the lid member 413 moves to the (-Y) side and the support tray 415 is pulled out from the processing chamber 412. The position of the support tray 415 at this time will be referred to as the "pull-out position" below. Also, as the lifting member 433 rises, the lift pin 437 protrudes above the upper surface (support surface) of the support tray 415. When the base member 435 rises due to the rise of the lifting member 433, the lift pin 437 protrudes above the support surface through the through hole 417.

[0060] As shown in Figure 6(a), the substrate S is transported while being held by a hand 31 provided on the transport robot 30 of the transport device 3. The lift pin 437 protrudes above the upper surface of the hand 31, and the substrate S is transferred from the hand 31 to the lift pin 437. The shape and arrangement of the hand 31 and the lift pin 437 are determined so as not to interfere with each other. In this state, the hand 31 can be retracted to the side. As shown in Figure 6(b), the lifting member 433 descends, causing the substrate S, supported by the lift pin 437, to descend.

[0061] Finally, as shown in Figure 6(c), the lower surface of the substrate S contacts the upper surface of the support tray 415, and the lift pin 437 descends below the support tray 415, thereby transferring the substrate S from the lift pin 437 to the support tray 415. In this way, the substrate S is transferred from the transport robot 30 to the support tray 415. Subsequently, as shown in Figure 6(d), the lid member 413 moves in the (+Y) direction, and the substrate S, together with the support tray 415, is housed in the processing space SP of the processing chamber 412.

[0062] The removal of the processed substrate S is the reverse of the above. That is, as shown in Figure 6(c), after the processed substrate S is pulled out of the processing chamber 412 together with the support tray 415, the lifting member 433 rises, causing the lift pin 437 to lift the substrate S from the support tray 415. Then, as shown in Figure 6(a), the substrate S is handed over from the lift pin 437 to the hand 31 that enters from the outside, and the substrate S is held by the hand 31. The hand 31 then removes the substrate S to the outside, and the substrate S is discharged from the supercritical processing apparatus 4.

[0063] As described above, a liquid film LP is formed on the upper surface of the substrate S before it is brought into the supercritical fluid processing apparatus 4 for surface protection. The liquid constituting the liquid film LP is later replaced by the supercritical fluid introduced, but in order to improve the efficiency of the process, it is better to reduce the amount of liquid brought into the processing chamber 412. It is difficult to reduce the amount of liquid constituting the liquid film LP in order to reliably protect the entire upper surface of the substrate S.

[0064] On the other hand, it is desirable that no liquid adheres to the underside of the substrate S. Since the substrate S is transported into the processing chamber 412 while placed on the support tray 415, any liquid adhering to the underside of the substrate S will enter the tiny gap between the underside of the substrate S and the upper surface of the support tray 415. In that case, it will take a long time to replace and remove this liquid with the supercritical processing fluid, and any remaining liquid that cannot be completely removed may cause processing defects. For this reason, it is required that any liquid adhering to the underside of the substrate S be sufficiently removed before the substrate S is transported into the processing chamber 412, and more preferably before the substrate S is placed on the support tray 415.

[0065] Therefore, in this substrate processing system, after a liquid film is formed on the upper surface Sa of the substrate S in the wet processing apparatus 2, a process of blowing gas onto the lower surface of the substrate S is performed for a certain period of time. This removes the liquid that has adhered to the lower surface of the substrate S after the liquid film has been formed. There are several approaches to the specific configuration that makes this possible, and three embodiments will be described below. In addition, components common to each embodiment will be denoted by the same reference numerals, and redundant explanations will be omitted.

[0066] <First Embodiment> Figure 7 shows a first embodiment for performing gas blowing. More specifically, Figures 7(a) and 7(b) show the main parts of the wet processing apparatus 2A of the first embodiment. As shown in Figure 7(a), in this embodiment, the center of the rotating support shaft 213 is finished as a cavity, and its interior is a gas passage 215. Its upper end is connected to a gas nozzle 216 provided on the upper surface of the spin chuck 211. A suitable gas, such as nitrogen gas or dry air, is supplied to the gas passage 215 from a gas supply source 25 in accordance with a control command from the control unit 9. The supplied gas is blown from the gas nozzle 216 toward the lower surface of the substrate S.

[0067] After a liquid film LP is formed on the substrate S and the rotation of the substrate S stops, gas is supplied from the gas supply source 25 to a gas passage 215 located inside the rotating support shaft 213. The gas is discharged from the gas nozzle 216 and blown onto the lower surface Sb of the substrate S. As a result, an airflow is formed on the lower surface Sb of the substrate S, flowing from the center to the periphery, and this airflow can blow away any liquid adhering to the lower surface Sb of the substrate S.

[0068] Since the liquid may splash into the surrounding area, it is desirable that the cup 221 be positioned in an upward position. Although the rotation of the substrate S is stopped here, the substrate S can also be rotated at a low speed as long as the liquid film LP on the upper surface Sa can be maintained.

[0069] Furthermore, as shown in Figure 7(b), gas may be blown onto the lower surface Sb from the time the processing liquid L2 for liquid film formation is supplied from the nozzle 244. In this case, it is possible to quickly discharge the liquid that flows around to the lower surface Sb of the substrate S during liquid film formation, thereby reducing the adhesion of liquid to the lower surface Sb itself.

[0070] In short, providing a step to blow gas onto the lower surface Sb of the substrate S for a certain period after the supply of the liquid film-forming treatment solution is stopped, more preferably after the rotation of the substrate S is stopped, and before the substrate S is transported to the supercritical fluid processing apparatus 4 and placed on the support tray 415, is effective in suppressing the adhesion of liquid to the lower surface Sb. Specifically, the gas blowing should be performed between the start of step S103 and the end of step S105 in Figure 2.

[0071] <Second Embodiment> Figure 8 shows a second embodiment for performing gas blowing. More specifically, Figure 8(a) is a side cross-sectional view showing the internal structure of the wet processing apparatus 2B of the second embodiment, and Figure 8(b) is a plan cross-sectional view. In this embodiment, a gas nozzle 251 is positioned inside the processing container 200 near an opening 202 provided with a shutter 201. As shown in Figure 8(b), the gas nozzle 251 is a porous nozzle with an elongated outer shape extending along the Y direction and a plurality of discharge ports 252 arranged in the Y direction.

[0072] The gas nozzles 251 are positioned below the path of the substrate S as it is discharged from the spin chuck 211 through the opening 202, with each discharge port 252 opening upward. As shown by the dotted arrows, when the substrate S is discharged by the hand 31 of the transport robot 30, gas supplied from the gas supply source 25 is discharged upward from each discharge port 252. Therefore, as the substrate S, after liquid film formation, passes above the gas nozzles 251, gas is blown onto the underside of the substrate S, thereby blowing away any liquid adhering to the underside of the substrate S.

[0073] With this configuration, even if liquid flows from the top to the bottom after the substrate S has started moving to be removed from the wet processing apparatus 2 after the liquid film has formed, it is possible to remove it within the wet processing apparatus 2. In order to enhance the liquid removal effect, for example, the hand 31 may be temporarily stopped or its movement speed reduced when the substrate S being transported is directly above the nozzle 251.

[0074] <Third Embodiment> Figure 9 shows a third embodiment for performing gas blowing. In the first and second embodiments, the configuration for blowing gas is provided in the wet processing apparatus 2. On the other hand, in this third embodiment, the transport robot 30 has the configuration for blowing gas.

[0075] Specifically, the hand 31A of the transport robot 30 in this embodiment has a structure in which two substrate support parts 312 extend substantially parallel to each other from a base part 311 attached to a telescopic arm (not shown). Each substrate support part 312 is provided with a support pin 313 that partially contacts the back surface and peripheral edge of the substrate S to support the substrate S. A gas nozzle 315 for blowing gas is attached to the base part 311.

[0076] In the gas nozzle 315, multiple discharge ports 316 are arranged horizontally, making the gas nozzle 315 a porous nozzle. Each discharge port 316 is located on the side of the gas nozzle 315 facing the substrate S, and discharges the gas supplied from the gas supply source 25 in a nearly horizontal direction. As shown in Figure 9(b), in a horizontal view, the discharge ports 316 open below the lower surface Sb of the substrate S, which is supported by the support pins 313, and blow out the gas at a relatively narrow angle, as indicated by the dashed arrows. On the other hand, as shown by the dashed arrows in Figure 9(a), the gas is blown out at a relatively wide angle in the horizontal direction. Therefore, the gas spreads along the lower surface Sb of the substrate S, blowing away any liquid adhering to this surface.

[0077] The hand 31A is housed in the cover 32 and extends out of the cover 32 as needed. During the process in which the transport robot 30 receives the substrate S from the wet processing apparatus 2 and transports it to the supercritical processing apparatus 4, the hand 31A can be either housed in the cover 32 or extended out of the cover 32 into the processing chamber 200 or processing chamber 400. Therefore, any liquid blown away by the gas blowing falls only into the cover 32 or into the processing chambers 200 or 400, preventing the liquid from splashing into the surroundings.

[0078] The gas nozzle 315 discharges gas from the discharge port 316 for at least a portion of the period during which the hand 31A holds the substrate S. The gas may be discharged for the entire period, or the gas may be discharged continuously regardless of whether the substrate S is present or not. The gas flow rate may be constant, or there may be a period during which the flow rate is temporarily increased to enhance the liquid removal effect. In this embodiment, it is possible to spray gas from immediately after the start of transport until immediately before being transported into the processing chamber 412.

[0079] Furthermore, regarding the gas supply source 25, if nitrogen gas or the like is supplied into the cover 32 for purposes such as controlling the atmosphere inside the cover 32 or protecting the electrical and mechanical contacts of the transport robot 30, it is possible to supply gas from that gas supply source to the gas nozzle 315.

[0080] <Other> As described above, in each of the above embodiments, the spin chuck 211 functions as the "substrate holding part" of the present invention. In addition, the gas nozzles 216, 251, and 315 function as the "gas discharge part" of the present invention.

[0081] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, although three embodiments have been described above as configurations for blowing gas onto the underside of a substrate, these can be implemented not only individually but also in combination of two or more.

[0082] Furthermore, in the above embodiment, for example, carbon dioxide is used as the processing fluid for supercritical fluid treatment, nitrogen gas or dry air is used as the gas sprayed onto the underside of the substrate, and IPA is used as the liquid for forming the liquid film. However, this is merely an example, and the chemical substances used are not limited to these.

[0083] As described above with examples of specific embodiments, in the substrate processing method according to the present invention, the supercritical processing apparatus supports the substrate in a horizontal position by placing the substrate, which is transported by the transport device, on a flat support tray, and the gas discharge unit may be configured to blow gas before the substrate is placed on the support tray.

[0084] Alternatively, for example, the wet processing apparatus may be configured to form a liquid film with a substrate placed on the upper surface of a flat, rotating substrate holder, and the gas discharge unit may discharge gas from a nozzle provided on the upper surface of the substrate holder. In this case, the gas discharge unit may spray gas after the rotation of the substrate holder has stopped following the formation of the liquid film.

[0085] For example, the gas discharge unit may be configured to discharge gas from a nozzle located below the path of the substrate being transported out of the wet processing apparatus within the wet processing apparatus. Furthermore, the transport device may be provided with a handle for holding the substrate, and the gas discharge unit may be configured to discharge gas toward the substrate from a nozzle provided on the handle.

[0086] Here, nitrogen gas or dry air can be suitably used as the gas discharged from the gas discharge section.

[0087] Furthermore, this invention can be realized as a substrate processing system comprising a wet processing apparatus for forming a liquid film on the upper surface of a substrate, a supercritical processing apparatus for housing the substrate with the liquid film formed on it in a chamber and processing it with a supercritical processing fluid, and a transport device for transporting the substrate with the liquid film formed on it into the chamber of the supercritical processing apparatus. For example, the wet processing apparatus can be configured to have a nozzle positioned below the path of the substrate being discharged from the wet processing apparatus, so that the nozzle blows gas onto the lower surface of the substrate being discharged by the transport device. Alternatively, the transport device may be configured to have a hand for holding the substrate and a nozzle provided on the hand for blowing gas onto the lower surface of the substrate held by the hand.

[0088] In these substrate processing systems, for example, after a liquid film has been formed on the substrate, the system can be configured to blow gas toward the lower surface of the substrate, which is supported in a horizontal position, for at least a portion of the time the substrate is outside the chamber.

[0089] Furthermore, for example, if the supercritical fluid processing apparatus has a flat support tray on which a substrate is placed and housed in the chamber, it is preferable that the nozzle blows gas before the substrate is placed on the support tray. This prevents liquid from entering the gap between the substrate and the support tray, thereby preventing problems in supercritical fluid processing such as requiring a long time for liquid replacement or causing processing defects due to residual liquid. [Industrial applicability]

[0090] This invention can be applied to all types of substrate processing apparatus that use supercritical fluids to process substrates. In particular, it can be suitably applied to substrate drying processes in which substrates such as semiconductor substrates are dried using supercritical fluids. [Explanation of Symbols]

[0091] 1. Substrate Processing System 2 Wet processing apparatus 3. Conveying device 4. Supercritical Fluid Processing System 31 Hand 211 Spin chuck (substrate holding part) 216,251,315 Gas nozzle (gas discharge part) 412 Processing Chamber (Chamber) 415 Support Tray S substrate SP Processing Space

Claims

1. A wet processing apparatus performs the step of forming a liquid film on the upper surface of the substrate, The transport device carries the substrate on which the liquid film has been formed into the chamber of the supercritical fluid processing apparatus, The supercritical processing apparatus comprises the steps of processing the substrate with a supercritical fluid in the chamber and Equipped with, The process further includes, after the liquid film has been formed on the substrate, and for at least a portion of the time the substrate is outside the chamber, a gas discharge unit blows gas toward the lower surface of the substrate which is supported in a horizontal position, The transport device is provided with a handle that supports the substrate from below. A substrate processing method wherein the gas discharge unit has a nozzle provided on the hand toward the substrate, and the nozzle discharges the gas horizontally from one end to the other of the lower surface of the substrate.

2. In the supercritical apparatus, the substrate transported by the transport device is placed on a flat support tray to support the substrate in a horizontal position. The substrate processing method according to claim 1, wherein the gas discharge unit blows the gas before the substrate is placed on the support tray.

3. The conveying device is provided with a cover that houses the hand so that it can move forward and backward, The substrate processing method according to claim 1 or 2, wherein the nozzle discharges the gas while the hand is housed in the cover.

4. The substrate processing method according to claim 1 or 2, wherein the gas is nitrogen gas or dry air.

5. A wet processing apparatus for forming a liquid film on the upper surface of a substrate, A supercritical processing apparatus that houses the substrate on which the liquid film has been formed in a chamber and processes it with a supercritical fluid, A transport device for transporting the substrate on which the liquid film has been formed into the chamber of the supercritical device. Equipped with, The conveying device is a substrate processing system comprising a hand that supports the substrate from below, and a nozzle provided on the hand that blows gas horizontally from one end to the other on the lower surface of the substrate held by the hand.

6. The conveying device has a cover that houses the hand so that it can move forward and backward, The substrate processing system according to claim 5, wherein the nozzle discharges the gas while the hand is housed in the cover.

7. The substrate processing system according to claim 5 or 6, wherein, after the liquid film has been formed on the substrate, and for at least a portion of the time the substrate is outside the chamber, the nozzle blows the gas onto the lower surface of the substrate, which is supported in a horizontal position.

8. The supercritical apparatus has a flat support tray on which the substrate is placed and which is housed in the chamber. The substrate processing system according to claim 7, wherein the nozzle blows the gas before the substrate is placed on the support tray.

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