Substrate processing method and substrate processing system

Abstract

In a substrate processing method and a substrate processing system according to the present invention, the inside of a pattern is warmed while maintaining a liquid filling state. The convection diffusion of a liquid component present in the pattern is thereby promoted. That is, the residual liquid present on the inner bottom surface is also convection-diffused in the organic solvent and mixed with the organic solvent. As a result, the drying process with the processing fluid in a supercritical state is performed in a state where no residual liquid is present on the inner bottom surface of the pattern, i.e., in a so-called residual-liquid-free state.

Description

Substrate processing method and substrate processing system

[0001] The present invention relates to a technique for drying a substrate in a processing chamber, and more particularly to a process in which a substrate covered with a liquid film is treated with a processing fluid in a supercritical state.

[0002] The disclosures in the specifications, drawings and claims of the following Japanese applications are incorporated herein by reference in their entirety: Japanese Patent Application No. 2023-138195 (filed August 28, 2023).

[0003] Processing processes for various substrates, such as semiconductor substrates and glass substrates for display devices, include treating the surface of the substrate with various processing fluids. Wet processing using liquids such as chemicals and rinses as processing fluids has been widely used. In recent years, processing using processing fluids in a supercritical state has also been put to practical use to dry substrates after such wet processing. This is particularly useful in drying substrates having a patterned surface on which a fine pattern is formed. This is because processing fluids in a supercritical state have a lower surface tension than liquids and have the property of penetrating deep into the gaps in the pattern. Using such processing fluids enables efficient drying processing. It is also possible to reduce the risk of pattern collapse due to surface tension during drying.

[0004] For example, a substrate processing system described in Patent Document 1 includes a substrate developing apparatus as an example of the "wet processing apparatus" of the present invention. In this substrate developing apparatus, as a final process within the apparatus, IPA (isopropyl alcohol), an example of the "organic solvent" of the present invention, is supplied to a substrate wetted with a rinse liquid. This performs IPA substitution, removing the rinse liquid from the surface of the substrate. A puddle of IPA liquid is then created on the surface of the substrate. In other words, a puddle-shaped liquid film containing IPA liquid is formed. As a result, the surface of the substrate is maintained wet with IPA liquid. Then, while maintaining the puddle state, the substrate is transported by a substrate transport device to a substrate drying apparatus, which is an example of the "supercritical processing apparatus" of the present invention, where a drying process is performed using a processing fluid in a supercritical state.

[0005] Japanese Patent Application Laid-Open No. 2013-201302

[0006] In wet processing equipment such as substrate developing equipment and substrate cleaning equipment, it is desirable to completely remove liquids such as rinse liquids from inside the pattern by IPA substitution. However, liquid may remain on the inner bottom surface of the pattern. If a substrate is loaded into a substrate drying equipment (supercritical processing equipment) with such residual liquid (hereinafter referred to as "residual liquid") remaining and a supercritical drying process is performed, the following problem may occur. That is, the replacement of the liquid components constituting the liquid film with the processing fluid in a supercritical state is likely to be incomplete. Therefore, a possible solution to this problem is to increase the amount of processing fluid used. However, this increases running costs and places a significant burden on society.

[0007] Even if the amount of processing fluid used is increased, residual liquid remains on the inner bottom surface of the pattern, which can cause the pattern to collapse. For this reason, the presence of residual liquid is one of the main causes of reduced product yield.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a technology for a substrate processing system in which a substrate having undergone wet processing and an organic solvent applied to its surface is transported from a wet processing apparatus to a supercritical processing apparatus, and the substrate is dried using a processing fluid in a supercritical state, which can improve yield while reducing the consumption of processing fluid and mitigating the environmental load.

[0009] One aspect of the present invention is a substrate processing method for processing a substrate having a pattern-formed surface on which a pattern is formed, comprising: (a) a step of performing, in a wet processing apparatus, a wet processing of the substrate by supplying a chemical liquid to the pattern-formed surface, a rinsing processing by supplying a rinse liquid to the pattern-formed surface, a substitution processing by supplying an organic solvent to the pattern-formed surface, and a puddle processing of supplying the organic solvent to the pattern-formed surface to form a liquid film of the organic solvent in a puddle state on the pattern-formed surface, in this order; (b) a step of transporting the substrate from the wet processing apparatus to a supercritical processing apparatus while maintaining the puddle state; and (c) a step of drying the substrate in the supercritical processing apparatus by contacting the puddle-state pattern-formed surface with a processing fluid in a supercritical state, wherein the method is characterized in that, in at least one of steps (a), (b), and (c), the inside of the pattern is heated while maintaining the puddle state.

[0010] Another aspect of the present invention is a substrate processing system for processing a substrate having a pattern-formed surface on which a pattern is formed, comprising: a wet processing apparatus that performs, in this order, wet processing of the substrate by supplying a chemical liquid to the pattern-formed surface, a rinsing process by supplying a rinse liquid to the pattern-formed surface, a replacement process by supplying an organic solvent to the pattern-formed surface, and a puddle process that forms a liquid film of organic solvent in a puddle state on the pattern-formed surface by supplying the organic solvent to the pattern-formed surface; a supercritical processing apparatus that dries the substrate by bringing a processing fluid in a supercritical state into contact with the puddle-state pattern-formed surface; and a substrate transport apparatus that transports the substrate from the wet processing apparatus to the supercritical processing apparatus while maintaining the puddle state, wherein at least one of the wet processing apparatus, substrate transport apparatus, and supercritical processing apparatus heats the inside of the pattern while maintaining the puddle state.

[0011] In the past, in wet processing equipment, after chemical processing was performed by supplying a chemical solution to a pattern-forming surface, a rinse process, a substitution process, and a puddle process were performed in that order. As a result, rinse liquid may remain on the inner bottom surface of the pattern, which can lead to increased consumption of processing fluid and reduced product yield. Therefore, in the present invention, the inside of the pattern is heated while maintaining the puddle state. This promotes convective diffusion of liquid components present in the pattern. In other words, the residual liquid present on the inner bottom surface is convectively diffused into the organic solvent and mixed with it. As a result, a drying process is performed using a supercritical processing fluid in a state where there is no residual liquid on the inner bottom surface of the pattern, i.e., a so-called residual liquid-free state.

[0012] As described above, according to the present invention, it is possible to carry out supercritical drying without leaving any residual liquid, thereby improving yield while reducing consumption of processing fluid.

[0013] Not all of the multiple components of each of the above-described aspects of the present invention are essential, and in order to solve some or all of the above-described problems or achieve some or all of the effects described in this specification, it is possible to modify, delete, or replace some of the multiple components with new components, or to delete some of the limitations, as appropriate. Furthermore, in order to solve some or all of the above-described problems or achieve some or all of the effects described in this specification, it is possible to combine some or all of the technical features included in one aspect of the present invention described above with some or all of the technical features included in another aspect of the present invention described above to form an independent aspect of the present invention.

[0014] FIG. 1 is a diagram showing a schematic configuration of a first embodiment of a substrate processing system according to the present invention. FIG. 2 is a side view showing the overall configuration of a wet processing apparatus. FIG. 3 is a diagram for explaining the operation of the wet processing apparatus. FIG. 4 is a diagram schematically showing the configuration and operation of a chuck pin. FIG. 5 is a side view showing the configuration of a supercritical processing apparatus. FIG. 6 is a perspective view showing the structure of a support tray. FIG. 7 is a diagram showing an overview of processing performed by the substrate processing system according to the first embodiment. FIG. 8 is a diagram showing pressure changes in a processing chamber. FIG. 9 is a diagram showing an example of the configuration of a wet processing apparatus equipped in a substrate processing system according to a second embodiment of the present invention. FIG. 10 is a diagram showing an overview of processing performed by the substrate processing system according to the second embodiment of the present invention. FIG. 11 is a diagram showing an example of the configuration of a wet processing apparatus equipped in a substrate processing system according to a third embodiment of the present invention. FIG. 12 is a diagram showing an overview of processing performed by the substrate processing system according to the third embodiment of the present invention. FIG. 13 is a diagram showing an overview of processing performed by the substrate processing system according to a fourth embodiment of the present invention.

[0015] 1 is a diagram showing the schematic configuration of a first embodiment of a substrate processing system according to the present invention. This substrate processing system 1 is a processing system for wet-processing various substrates, such as semiconductor wafers, by supplying a processing liquid to the upper surface of the substrate and then drying the substrate, and has a system configuration suitable for carrying out a substrate processing method according to the present invention. The substrate processing system 1 mainly comprises a wet-processing device 2, a substrate transfer device 3, a supercritical processing device 4, and a control device 9.

[0016] The wet processing device 2 receives a substrate to be processed and performs a predetermined wet processing. The type of processing is not particularly limited. Wet processing includes a development process using a chemical solution, which is performed in the conventional device described above, and a cleaning process for cleaning the substrate. In this case, a puddle of an organic solvent such as an IPA liquid is created on the pattern-forming surface of the substrate. The substrate transport device 3 transports the substrate from the wet processing device 2 while maintaining the puddle state, and transports it into the supercritical processing device 4. The supercritical processing device 4 performs a drying process (supercritical drying process) on the transported substrate using a processing fluid in a supercritical state. These devices are installed in a clean room. Therefore, the substrate transport device 3 transports the substrate S in the air atmosphere and under atmospheric pressure.

[0017] The control device 9 controls the operation of each of these devices to achieve predetermined processing. For this purpose, the control device 9 is equipped with 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 users and external devices. The operations of the devices described below are achieved by the CPU 91 executing control programs written in advance in the storage 93 and causing each part of the device to perform a predetermined operation.

[0018] When the CPU 91 executes a predetermined control program, functional blocks such as a wet processing control unit 95 that controls the operation of the wet processing apparatus 2, a transport control unit 96 that controls the operation of the substrate transport apparatus 3, and a supercritical processing control unit 97 that controls the operation of the supercritical processing apparatus 4 are realized in software in the control device 9. Note that at least a part of each of these functional blocks may be configured by dedicated hardware.

[0019] The "substrate" in this embodiment can be any of a variety of substrates, including semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, substrates for FEDs (Field Emission Displays), substrates for optical disks, substrates for magnetic disks, and substrates for magneto-optical disks. The following description will be given with reference to the drawings, taking as an example a substrate processing apparatus used primarily for processing disc-shaped semiconductor wafers. However, the present invention can be similarly applied to processing the various substrates exemplified above. Various substrate shapes can also be used.

[0020] In the following description, a substrate having a pattern formed on only one main surface will be used as an example. Here, the main surface on which a pattern or the like is formed will be referred to as the "front surface," and the opposite main surface on which no pattern is formed will be referred to as the "rear surface." Furthermore, the main surface of the substrate facing downward will be referred to as the "bottom surface," and the main surface of the substrate facing upward will be referred to as the "top surface." In the following description, the top surface will be referred to as the front surface.

[0021] 2A and 2B are diagrams showing an example of the configuration of a wet processing apparatus provided in a substrate processing system according to a first embodiment of the present invention. More specifically, FIG. 2A is a side view showing the overall configuration of the wet processing apparatus, and FIG. 2B is a diagram for explaining the operation of the wet processing apparatus. This wet processing apparatus 2 is an apparatus for processing a substrate by supplying a processing liquid to the upper surface of a substrate S. The operation of the wet processing apparatus 2 is controlled by a wet processing control unit 95 of the control device 9.

[0022] The wet processing apparatus 2 supplies a processing liquid to the surface (pattern formation surface) Sa of the substrate S and performs various processes (chemical processing, rinsing processing, substitution processing, liquid film formation processing, etc.), which will be described in detail later. For this purpose, the wet processing apparatus 2 includes a substrate holding unit 21, a splash guard 22, and processing liquid supply units 23 and 24 inside a processing chamber 200. The operations of these units are controlled by a wet processing control unit 95 provided in the control device 9. The substrate holding unit 21 has a disk-shaped spin chuck 211 having approximately the same diameter as the substrate S, and a plurality of chuck pins 212 are provided on the periphery of the spin chuck 211.

[0023] 3A and 3B are diagrams schematically illustrating the configuration and operation of the chuck pin, with FIG. 3A showing the chuck pin in a chucked state (clamped state) and FIG. 3B showing the chuck pin in an unchucked state (open state). Although not shown, in this embodiment, twelve chuck pins 212 are provided radially around the rotation axis AX of the spin chuck 211. Each chuck pin 212 is disposed on the upper surface of the peripheral edge of the spin chuck 211 so as to be movable in the radial direction D. Here, the "radial direction D" refers to the longitudinal direction of an imaginary line connecting the rotation axis AX and the chuck pin 212.

[0024] The multiple chuck pins 212 all have the same configuration. Therefore, the following description will focus on the configuration of one chuck pin 212, and the components of the other chuck pins 212 will be denoted by the same reference numerals and will not be described further. As shown in FIG. 3 , the chuck pin 212 has a chuck contact surface 212a. This chuck contact surface 212a is movable along the radial direction D on the upper surface of the peripheral edge of the spin chuck 211. The chuck pin 212 has a lower contact surface 212b above the chuck contact surface 212a. The lower contact surface 212b slopes downward as it progresses in the direction (+D) toward the rotation axis AX. A curved contact surface 212c extends upward from the end of the lower contact surface 212b on the (-D) direction side. This curved contact surface 212c is finished into a curved surface facing the rotation axis AX. Furthermore, an upper abutment surface 212d extends upward from the upper end of the curved abutment surface 212c. This upper abutment surface 212d slopes upward as it progresses in the direction (+D) toward the rotation axis AX. More specifically, as shown in FIG. 3 , the curved abutment surface 212c is disposed between the upper abutment surface 212d and the lower abutment surface 212b, and is directly continuous with the upper abutment surface 212d and the lower abutment surface 212b. Therefore, when the substrate abutment portion 212e, where the upper abutment surface 212d, the curved abutment surface 212c, and the lower abutment surface 212b are connected and abut against the substrate S, is viewed from a horizontal direction perpendicular to the radial direction D, the substrate abutment portion 212e has a substantially C-shape. In other words, the chuck pin 212 is capable of reciprocating along the radial direction D with the substrate abutment portion 212e facing the rotation axis AX.

[0025] The chuck pins 212 are connected to a chuck driver 215. The chuck driver 215 moves the chuck pins 212 in the radial direction D in response to a command from the wet process control unit 95. For example, when transferring the substrate S to or from the substrate transport device 3, the chuck driver 215 moves the chuck pins 212 in the direction (−D) to position them at a non-chucking position, as shown in FIG. 3B. At this time, the curved contact surface 212c and the upper contact surface 212d are slightly farther from the rotation axis AX than the radius of the substrate S. On the other hand, the lower contact surface 212b is located below the substrate S. Therefore, as shown in FIG. 3B, the substrate S is supported only by the lower contact surface 212b at a position of the lower contact surface 212b that is farther in the +D direction from the curved contact surface 212c.

[0026] On the other hand, when chucking the substrate S, as shown in FIG. 3A, the chuck driver 215 moves the chuck pin 212 in the +D direction and positions it at the chuck position. By moving the chuck pin 212 from the non-chuck position to the chuck position in this manner, the support position of the substrate S on the lower contact surface 212b shifts in the -D direction. When the movement of the chuck pin 212 to the chuck position is completed, the substrate S is supported by the lower contact surface 212b, the curved contact surface 212c, and the upper contact surface 212d. In other words, substrate chucking is completed.

[0027] When the substrate S is released from the chuck, the chuck pins 212 move in the reverse order to the above, and the support position of the substrate S on the lower contact surface 212b shifts in the (+D) direction.

[0028] Furthermore, as the support position of the substrate S on the lower contact surface 212b moves in the radial direction D, the height position of the substrate S in the vertical direction Z is displaced by a distance dz. Therefore, when the wet process control unit 95 issues a reciprocating movement command to the chuck driving unit 215, the chuck pins 212 move reciprocatingly in the radial direction D, and the substrate S is repeatedly raised and lowered in synchronization therewith. In other words, it is possible to apply vibrations to the substrate S in the up and down direction. Note that, although the present embodiment uses the chuck pins 212 capable of applying vibrations, conventional chuck pins without a vibration-applying function may also be used.

[0029] 2A and 2B, the description of the configuration of the wet processing apparatus 2 will be continued. The spin chuck 211 is supported by a rotation support shaft 213 extending downward from the center of its lower surface so that its upper surface is horizontal. The rotation support shaft 213 is rotatably supported by a rotation mechanism 214 attached to the bottom of the processing chamber 200. The rotation mechanism 214 has a built-in rotation motor (not shown), and when the rotation motor rotates in response to a control command from the control device 9, the spin chuck 211 directly connected to the rotation support shaft 213 rotates about the rotation axis AX indicated by the dashed-dotted line. In FIG. 2, the up-down direction is the vertical direction. As a result, the substrate S is rotated about the rotation axis AX while remaining in a horizontal position.

[0030] A splash guard 22 is provided to surround the substrate holding part 21 from the side. The splash guard 22 has a generally cylindrical cup 221 provided to cover the peripheral part of the spin chuck 211, and a liquid receiving part 222 provided below the outer periphery of the cup 221. The cup 221 moves up and down in response to a control command from the control device 9. The cup 221 moves up and down between a lower position where the upper end of the cup 221 is lowered below the peripheral part of the substrate S held by the spin chuck 211, as shown in Fig. 2A, and an upper position where the upper end of the cup 221 is located above the peripheral part of the substrate S, as shown in Fig. 2B.

[0031] 2A, 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, for example, the substrate S is loaded onto or unloaded from the spin chuck 211.

[0032] 2B , when the cup 221 is in the upper position, it surrounds the peripheral edge of the substrate S held by the spin chuck 211. This prevents the processing liquid shaken off from the peripheral edge of the substrate S during liquid supply, which will be described later, from scattering inside the chamber 200, making it possible to reliably collect the processing liquid. That is, as the substrate S rotates, droplets of the processing liquid shaken off from the peripheral edge of the substrate S adhere to the inner wall of the cup 221, flow downward, and are collected by the liquid receiving portion 222 arranged below the cup 221. In order to collect multiple processing liquids individually, multiple stages of cups may be provided concentrically.

[0033] 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 pivotal support shaft 232 that is rotatably provided on a base 231 fixed to the processing chamber 200. The pivotal support shaft 232 rotates in response to a control command from the control device 9, causing the arm 233 to swing, and the nozzle 234 at the tip of the arm 233 moves between a retracted position retracted to the side from above the substrate S as shown in Fig. 2A and a processing position above the substrate S as shown in Fig. 2B.

[0034] The nozzle 234 is connected to a processing liquid supply source 238, and when an appropriate processing liquid is delivered from the processing liquid supply source 238, the processing liquid is ejected from the nozzle 234 toward the substrate S. As shown in FIG. 2B , the spin chuck 211 rotates at a relatively low speed to rotate the substrate S, and a processing liquid F1 is supplied from the nozzle 234 positioned above the center of rotation of the substrate S, thereby processing the surface Sa of the substrate S with the processing liquid L1. In this embodiment, a chemical liquid (such as a developer, an etching liquid, or a cleaning liquid) and a rinse liquid are used as the processing liquid L1, and therefore the processing liquid supply source 238 includes a chemical liquid supply source 238A and a DIW supply source 238B. In addition, a heater 239 is inserted in the piping connecting the DIW supply source 238B and the nozzle 234. The heater 239 heats room-temperature deionized water (DIW) that functions as a rinse liquid and is supplied from the DIW supply source 238B in response to a heating command from the wet process control unit 95, to generate DIW at a temperature higher than room temperature (hereinafter referred to as "high-temperature DIW"). In this specification, "room temperature" refers to a temperature range of 5° C. to 35° C. The temperature of the high-temperature DIW will be described later.

[0035] The other processing liquid supply unit 24 also has a configuration corresponding to that of the above-described first processing liquid supply unit 23. That is, the second processing liquid supply unit 24 has a base 241, a pivotal support shaft 242, an arm 243, a nozzle 244, etc., and these configurations are equivalent to those corresponding to those in the first processing liquid supply unit 23. The pivotal support shaft 242 rotates in response to a control command from the control device 9, causing the arm 243 to swing. The nozzle 244 at the tip of the arm 243 supplies the processing liquid to the surface Sa of the substrate S.

[0036] In this embodiment, the second processing liquid supply unit 24 is used for the purpose of carrying out the substitution process and the liquid film forming process. That is, the substrate S after the wet process is transported to the supercritical processing device 4 and subjected to the supercritical drying process, but in order to prevent the surface of the substrate S from being exposed and oxidized during transportation or the fine pattern formed on the surface from collapsing, the substrate S is transported in a state where its surface is covered with a puddle-shaped liquid film.

[0037] The liquid that constitutes the liquid film is an organic solvent such as isopropyl alcohol (IPA) or acetone, which has a surface tension lower than that of water, which is the main component of the processing liquid used in the chemical processing and rinsing processing. These organic solvents are supplied from an organic solvent supply source 248.

[0038] Here, two sets of processing liquid supply units are provided in the wet processing apparatus 2, but the number of processing liquid supply units provided, their structures, and functions are not limited to this. For example, only one set of processing liquid supply units may be provided, or three or more sets may be provided. Furthermore, one processing liquid supply unit may be provided with multiple nozzles. For example, multiple nozzles may be provided at the tip of one arm. Furthermore, in addition to the above-mentioned mode in which the processing liquid is discharged while the nozzle is positioned at a predetermined position, a mode in which the processing liquid is discharged while the nozzle moves in a scanning motion along the surface Sa of the substrate S may also be included.

[0039] Returning to Figure 1, the explanation will continue. The substrate transfer device 3 is provided with a transfer robot 30 having a hand 31 attached to the tip of an extendable and rotatable arm. The hand 31 can support a substrate by partially abutting the underside of the substrate, and as shown by the dotted lines in Figure 1, is movable toward and away from both the wet treatment device 2 and the supercritical treatment device 4. This allows substrates to be loaded into and unloaded from both the wet treatment device 2 and the supercritical treatment device 4. The operation of the transfer robot 30 is controlled by a transfer control unit 96 of the control device 9. There are many known technologies for this type of transfer robot, and any of these can be appropriately selected and used in this embodiment, so a detailed description will be omitted.

[0040] 4 is a side view showing the configuration of a supercritical processing apparatus. The supercritical processing apparatus 4 is an apparatus that performs a drying process using a processing fluid in a supercritical state on a substrate S after wet processing. More specifically, the supercritical processing apparatus 4 is an apparatus that receives the substrate S after wet processing, replaces the liquid remaining on the substrate S with the processing fluid in a supercritical state, and then discharges the processing fluid, thereby finally bringing the substrate S to a dry state.

[0041] The supercritical processing apparatus 4 includes a processing unit 41, a transfer unit 43, and a supply unit 45. The processing unit 41 is the main unit that performs the supercritical drying process. The transfer unit 43 receives the wet-processed substrate S transported by the substrate transport device 3 and transports 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 chemical substances, power, energy, etc. required for the process to the processing unit 41 and the transfer unit 43. These operations are controlled by the control device 9, particularly the supercritical processing control unit 97.

[0042] The processing unit 41 has a structure in which a processing chamber 412 is mounted on a pedestal 411. The processing chamber 412 is constructed by combining several metal blocks, and its interior is hollow, constituting a processing space SP. The substrate S to be processed is loaded into the processing space SP and undergoes processing. A slit-shaped opening 421 that is elongated in the X direction is formed on the (-Y) side surface of the processing chamber 412. The processing space SP communicates with the external space via the opening 421. The cross-sectional shape of the processing space SP is generally the same as the opening shape of the opening 421. In other words, 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 that extends in the Y direction.

[0043] A lid member 413 is provided on the (-Y) side surface 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 attached in a horizontal position to the (+Y) side surface of the lid member 413. The upper surface of the support tray 415 forms a support surface on which the substrate S can be placed. The lid member 413 is supported by a support mechanism (not shown) so as to be horizontally movable in the Y direction.

[0044] The lid member 413 can be moved toward and away from the processing chamber 412 by an advancing / retracting mechanism 453 provided in the supply unit 45. Specifically, the advancing / retracting mechanism 453 has a linear motion mechanism such as a linear motor, a linear motion guide, a ball screw mechanism, a solenoid, or an air cylinder. Such a linear motion mechanism moves the lid member 413 in the Y direction. The advancing / retracting mechanism 453 operates in response to a control command from the control device 9.

[0045] When the cover member 413 moves in the (-Y) direction to move away from the processing chamber 412 and the support tray 415 is pulled out from the processing space SP through the opening 421 as shown by the dotted line, access to the support tray 415 becomes possible. That is, it becomes possible to place a substrate S on the support tray 415 and to remove a substrate S placed on the support tray 415. On the other hand, when the cover member 413 moves in the (+Y) direction, the support tray 415 is accommodated within the processing space SP. When a substrate S is placed on the support tray 415, the substrate S is carried into the processing space SP together with the support tray 415.

[0046] 5 is a perspective view showing the structure of the support tray 415. The support tray 415 has a tray member 416 and a plurality of support pins 417. The tray member 416 has a structure in which, on the horizontal and flat upper surface of a flat plate-like structure, there is provided a recess 418 that corresponds to the planar size of the substrate S, more specifically, has a diameter slightly larger than the diameter of the circular substrate S.

[0047] The recess 418 partially extends to the side surface of the tray member 416. In other words, the side wall surface of the recess 418 is not circular but is partially cut out. Therefore, at this cutout portion, part of the bottom surface 418a of the recess 418 directly connects to the side surface. In this example, such cutout portions are provided at both ends on the X side and the (+Y) side end of the support tray 415, and at these locations, the bottom surface 418a directly connects to the side surface.

[0048] Furthermore, through holes 419 for inserting the lift pins 437 are formed in the bottom surface 418a at positions corresponding to the lift pins 437 of the transfer unit 43. The lift pins 437 move up and down through the through holes 419, thereby realizing a state in which the substrate S is accommodated in the recess 418 and a state in which the substrate S is lifted above the recess 418.

[0049] A plurality of support pins 417 are arranged around the periphery of the recess 418. The number of support pins 417 to be arranged is arbitrary, but three or more is desirable in terms of stably supporting the substrate S. In this embodiment, three support pins 417 are attached to the tray member 416 so as to surround the bottom surface 418a in a plan view from above. As shown in the partially enlarged view of FIG. 5, the support pin 417 has a height restriction portion 417a and a horizontal position restriction portion 417b.

[0050] The height restriction portion 417a has a flat upper surface and abuts against the peripheral edge of the lower surface of the substrate S, thereby supporting the substrate S and restricting its position in the vertical direction Z (hereinafter referred to as the "height position"). On the other hand, the horizontal position restriction portion 417b extends above the upper end of the height restriction portion 417a and abuts against the side surface of the substrate S, thereby restricting the position of the substrate S in the horizontal directions (X and Y directions). By such support pins 417, the substrate S is supported in a horizontal position facing the bottom surface 418a of the recess 418 while being spaced above the bottom surface 418a.

[0051] The lid member 413 moves in the (+Y) direction to close the opening 421, thereby sealing the processing space SP. A seal 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 processing space SP in an airtight state. The seal member 422 is made of rubber, for example. The lid member 413 is fixed to the processing chamber 412 by a locking mechanism (not shown). As described above, in this embodiment, the lid member 413 can be switched between a closed state (solid line) in which the lid member 413 closes the opening 421 to seal the processing space SP, and a separated state (dotted line) in which the lid member 413 is separated significantly from the opening 421 to allow the substrate S to be inserted or removed.

[0052] The processing space SP is kept airtight while the substrate S is processed within the processing space SP. In this embodiment, the fluid supply unit 457 in the supply unit 45 delivers a processing fluid, such as carbon dioxide, which is a substance suitable for supercritical processing. The processing fluid is then pressurized within the processing chamber 412 to bring it to a supercritical state. The processing fluid is supplied to the processing unit 41 in a gaseous or liquid state. Carbon dioxide is a chemical suitable for supercritical drying because it reaches a supercritical state at relatively low temperatures and pressures and has the property of dissolving organic solvents commonly used in substrate processing. The critical point at which carbon dioxide reaches a supercritical state is an atmospheric pressure (critical pressure) of 7.38 MPa and a temperature (critical temperature) of 31.1°C.

[0053] When the processing space SP is filled with the processing fluid 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 manner, the substrate S is processed by the processing fluid in the processing chamber 412. The supply unit 45 is provided with a fluid recovery part 455, and the processed fluid is recovered by the fluid recovery part 455. The fluid supply part 457 and the fluid recovery part 455 are controlled by the supercritical processing control part 97.

[0054] The processing space SP has a shape and volume that can accommodate the support tray 415 and the substrate S supported thereon. That is, the processing space SP has a roughly rectangular cross-sectional shape that is wider than the width of the support tray 415 in the horizontal direction and greater than the combined height of the support tray 415 and the substrate S in the vertical direction, and a depth that can accommodate the support tray 415. In this way, the processing space SP has a shape and volume that can accommodate the support tray 415 and the substrate S. However, there is only a small gap between the support tray 415 and the substrate S and the inner wall surface of the processing space SP. Therefore, a relatively small amount of processing fluid is required to fill the processing space SP.

[0055] The fluid supply unit 457 supplies the processing fluid to the processing space SP further to the (+Y) side than the (+Y) end of the substrate S. Meanwhile, the fluid recovery unit 55 discharges the processing fluid that flows 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) end of the substrate S. As a result, laminar flows of the processing fluid from the (+Y) side toward the (-Y) side are formed above the substrate S and below the support tray 415 within the processing space SP.

[0056] The supercritical processing control unit 97 of the control device 9 determines the pressure and temperature in the processing space SP based on the detection results from a detection unit (not shown), and based on the results, controls the fluid supply unit 457 and the fluid recovery unit 455. This appropriately manages the supply of the processing fluid to the processing space SP and the discharge of the processing fluid from the processing space SP, and adjusts the pressure and temperature in the processing space SP in accordance with a predetermined processing recipe.

[0057] The transfer unit 43 is responsible for transferring the substrate S between the substrate transport device 3 and the support tray 415. For this purpose, the transfer unit 43 includes a main body 431, a lifting member 433, a base member 435, and multiple 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. Multiple 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 abutting its upper end against 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 ends have the same height.

[0058] The lifting member 433 can be moved 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, a linear motion guide, a ball screw mechanism, a solenoid, or an air cylinder, and this linear motion mechanism moves the lifting member 433 in the Z direction. The lifting mechanism 451 operates in response to a control command from the control device 9.

[0059] The base member 435 moves up and down as the lifting member 433 moves up and down, and the plurality of lift pins 437 move up and down integrally therewith. This allows 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 FIG. 5 , the substrate S is transferred with the support tray 415 pulled out of the chamber. For this purpose, the support tray 415 is provided with through holes 419 for inserting the lift pins 437. When the base member 435 moves up, the upper ends of the lift pins 437 pass through the through holes 419 and reach a position higher than the upper surface of the support tray 415. In this state, the substrate S transferred by the transfer robot 30 is transferred from the hand 31 of the transfer robot 30 to the lift pins 437. When the lift pins 437 move down, the substrate S is transferred from the lift pins 437 to the support tray 415. The substrate S can be removed by reversing the above procedure.

[0060] 6 is a diagram showing an overview of processes performed by the substrate processing system according to the first embodiment. This substrate processing system 1 receives a substrate S to be processed and sequentially performs a wet processing using a processing liquid such as a chemical solution, a rinse liquid, and an organic solvent, a transfer processing in which the wet-processed substrate S is transferred from a wet processing apparatus 2 to a supercritical processing apparatus 4, and a supercritical drying processing using a supercritical processing fluid. Specifically, when the substrate S to be processed is received in the wet processing apparatus 2 constituting the substrate processing system 1 (step S10), the wet processing (step S20), a transfer processing (step S30), and a supercritical drying processing (step S40) are performed in this order.

[0061] Here, the substrate S may be carried in directly by an external transfer device, or may be carried in from the external transfer device via a transfer robot 30 .

[0062] The wet processing apparatus 2 performs wet processing on the substrate S using a predetermined processing liquid (step S20). Like conventional apparatuses, this embodiment performs a chemical processing (step S21), a rinse processing (step S22), a substitution processing (step S23), and a liquid film formation processing (step S24) in this order. However, it differs from conventional apparatuses in the following respects. Specifically, in wet processing, after a predetermined chemical processing is performed by supplying a chemical liquid such as a developer or cleaning liquid in step S21, high-temperature DIW is supplied to the surface Sa of the substrate S as a rinse liquid (step S22). Subsequently, an organic solvent such as IPA is supplied to the substrate S, thereby replacing the rinse liquid adhering to the surface Sa of the substrate S with the organic solvent (step S23), and creating a liquid puddle of the organic solvent. That is, a liquid film LF is formed on the surface Sa of the substrate S (step S24: liquid film formation processing).

[0063] As in the conventional apparatus, the chemical liquid processing (step S21), rinsing processing (step S22), substitution processing (step S23), and liquid film forming processing (step S24) are performed in this order. Therefore, as shown in the upper right corner of the figure, DIW may remain as residual liquid on the inner bottom surface of the pattern PT formed on the surface Sa of the substrate S. However, in this embodiment, high-temperature DIW is used as the rinsing liquid, and the inside of the pattern PT is heated by the high-temperature DIW. This promotes convective diffusion of liquid components such as DIW and IPA present in the pattern PT. In other words, the residual liquid present on the inner bottom surface is convectively diffused into the IPA and mixed with it. In this way, a residual-liquid-free liquid film LF is formed on the surface Sa of the substrate S.

[0064] To promote convective diffusion, the temperature of the high-temperature DIW is preferably set to 40°C or higher, and may be set higher than the boiling point of IPA (82.4°C), for example. However, high DIW temperatures can cause splashing during liquid film formation. This splashing can make it difficult to maintain the liquid film LF. Therefore, it is preferable to determine the upper limit temperature of the high-temperature DIW at which the liquid film LF can be maintained using, for example, the monitoring technology described in Japanese Patent No. 7179568, a so-called dispense monitor. Therefore, in this embodiment, the wet process control unit 95 controls the heater 239 so that the temperature of the high-temperature DIW is 40°C or higher but lower than the upper limit temperature. As a result, the residual liquid can be removed while maintaining the puddle state. The method for setting the upper limit temperature is similar to that described in the embodiments described later.

[0065] The substrate S that has been subjected to the wet processing is transported, in a puddle state, from the wet processing apparatus 2 to the supercritical processing apparatus 4 by the substrate transport apparatus 3 (step S30).

[0066] The substrate S transported to the supercritical processing apparatus 4 is accommodated in the processing chamber 412 while still in a puddle of liquid. Specifically, the substrate S is transported with the pattern-formed surface (surface Sa) facing up, and the pattern-formed surface is covered with a thin liquid film LF. As shown by the dotted line in FIG. 4 , the lid member 413 moves toward the (−Y) side, and the support tray 415 is pulled out, and the lift pins 437 rise. The transport device transfers the substrate S to the lift pins 437. The lift pins 437 descend, and the substrate S is placed on the support tray 415. When the support tray 415 and the lid member 413 move together in the (+Y) direction, the support tray 415 supporting the substrate S is accommodated in the processing space SP within the processing chamber 412, and the opening 421 is closed by the lid member 413.

[0067] In this state, carbon dioxide as a processing fluid is introduced into the processing space SP in a gaseous state (step S41). When the substrate S is loaded, outside air enters the processing space SP, but this can be replaced by introducing the gaseous processing fluid. Furthermore, by injecting the gaseous processing fluid, the pressure inside the processing chamber 412 increases.

[0068] During the process of introducing the processing fluid, the processing fluid is continuously discharged from the processing space SP. That is, even while the processing fluid is being introduced by the fluid supply unit 457, the processing fluid is being discharged from the processing space SP by the fluid recovery unit 455. This allows the processing fluid used for processing to be discharged without remaining in the processing space SP, and prevents impurities such as residues that have been taken in the processing fluid from adhering again to the substrate S.

[0069] If the supply rate of the processing fluid is greater than the discharge rate, the density of the processing fluid in the processing space SP increases, causing an increase in the pressure inside the chamber. Conversely, if the supply rate of the processing fluid is less than the discharge rate, the density of the processing fluid in the processing space SP decreases, causing a decrease in the pressure inside the chamber. The supply of the processing fluid to the processing chamber 412 and the discharge of the processing fluid from the processing chamber 412 are performed based on a pre-created supply and discharge recipe. That is, the control device 9 controls the fluid supply unit 457 and the fluid recovery unit 455 based on the supply and discharge recipe, thereby adjusting the timing of supply and discharge of the processing fluid, its flow rate, etc.

[0070] 7 shows pressure changes within the processing chamber. When the processing fluid is carbon dioxide, its critical temperature is not significantly different from room temperature, so temperature changes during processing are not significant. Here, we will explain the phenomenon by focusing on the pressure within the chamber, which changes more significantly. The processing space SP is opened to the atmosphere and the internal pressure is atmospheric pressure Pa. At time T1 after the processing space SP is sealed, the introduction of the processing fluid begins, and the internal pressure begins to rise.

[0071] Pressurization continues until the pressure of the processing fluid in the processing space SP increases and exceeds the critical pressure Pc (step S42). At time T2 when the chamber reaches the critical pressure Pc, the processing fluid becomes supercritical in the chamber. That is, a phase change occurs in the processing space SP, causing the processing fluid to transition from a gas phase to a supercritical state. When the processing space SP is filled with the supercritical processing fluid, the IPA (or a mixture of IPA and DIW) covering the substrate S is replaced with the supercritical processing fluid. IPA and other substances liberated from the surface of the substrate S are dissolved in the processing fluid and discharged from the processing chamber 412 together with the processing fluid, and are removed from the substrate S. That is, the supercritical processing fluid has the function of replacing the IPA (or the mixture of IPA and DIW) adhering to the substrate S as the replacement liquid and discharging it out of the processing chamber 412.

[0072] After time T3 when the processing fluid has definitely transitioned to the supercritical state, the processing space SP is kept filled with the processing fluid in the supercritical state for a predetermined time (steps S43 and S44), whereby the liquid to be replaced adhering to the substrate S can be completely replaced and discharged to the outside of the chamber. Note that although the pressure Pm within the chamber in the supercritical state is shown as being constant in FIG. 7, the pressure may fluctuate as long as it does not become equal to or lower than the critical pressure Pc.

[0073] At time T4, when the replacement of the liquid to be replaced with the supercritical processing fluid in the processing chamber 412 is completed ("YES" in step S44), the processing fluid in the processing space SP is discharged to dry the substrate S. Specifically, the amount of fluid discharged from the processing space SP is increased to reduce the pressure inside the processing chamber 12 filled with the supercritical processing fluid (step S45).

[0074] During the depressurization process, the supply of the processing fluid may be stopped, or a small amount of processing fluid may be continuously supplied. When the processing space SP is depressurized from a state where it is filled with a processing fluid in a supercritical state, the processing fluid changes phase from the supercritical state to a gas phase. The vaporized processing fluid is discharged to the outside, and the substrate S is brought to a dry state. At this time, the depressurization rate is adjusted so as not to generate solid and liquid phases due to a sudden drop in temperature. That is, after depressurization begins at time T4, depressurization is performed at a relatively slow depressurization rate until time T5, when the pressure is reliably below the critical pressure Pc. As a result, the processing fluid in the processing space SP is directly vaporized from the supercritical state and discharged to the outside.

[0075] After time T5 when the processing fluid is completely vaporized, the depressurization rate is increased, thereby enabling the pressure to be reduced in a short time to atmospheric pressure Pa. In this way, the processing fluid is not liquefied during the entire period from time T4 when depressurization begins to time T6 when the pressure inside the chamber is reduced to atmospheric pressure Pa, and the formation of a gas-liquid interface on the substrate S with its surface exposed after drying is avoided.

[0076] As described above, in the supercritical drying process of this embodiment, the processing space SP is filled with a processing fluid in a supercritical state, and then the processing fluid is phase-changed to a gas phase and discharged, thereby efficiently replacing the liquid adhering to the substrate S and preventing it from remaining on the substrate S. Moreover, the substrate can be dried while avoiding problems caused by the formation of a gas-liquid interface, such as contamination of the substrate due to the adhesion of impurities and pattern collapse.

[0077] After processing, the substrate S is discharged to the subsequent process (step S50). That is, the cover member 413 moves in the (-Y) direction, whereby the support tray 415 is drawn out from the processing chamber 412, and the substrate S is delivered to an external transport device via the transfer unit 43. At this time, the substrate S is in a dry state. The content of the subsequent process is optional. In this way, the processing for one substrate S is completed. If there is another substrate to be processed, the process returns to step S101, a new substrate S is received, and the above processing is repeated.

[0078] As described above, according to the first embodiment, the wet processing apparatus 2 performs the rinse process using high-temperature DIW, thereby warming the inside of the pattern PT. Therefore, even if DIW remains in the pattern PT on the pattern formation surface (surface Sa) of the substrate S in a puddle state, the DIW (residual liquid) is effectively convected and diffused into the IPA and mixed therewith. Therefore, the drying process using the supercritical processing fluid is performed without residual liquid. This means that the supercritical drying process can be performed with high quality without excessive use of the supercritical processing fluid. As a result, the yield can be improved while reducing the consumption of the processing fluid.

[0079] As described above, in the first embodiment, DIW corresponds to an example of the "rinse liquid" of the present invention. Also, IPA corresponds to an example of the "organic solvent" of the present invention. The surface Sa of the substrate S corresponds to the "pattern formation surface" of the present invention. Also, the liquid film formation process corresponds to an example of the "liquid puddle process" of the present invention. Also, steps S20, S30, and S40 correspond to examples of "step (a)," "step (b)," and "step (c)" of the present invention, respectively.

[0080] In the first embodiment, high-temperature DIW is used as a means for heating the inside of the pattern PT, but other means may also be used.

[0081] 8 is a diagram showing an example of the configuration of a wet processing apparatus provided in a substrate processing system according to a second embodiment of the present invention. This substrate processing system 1 differs significantly from the first embodiment in that, instead of being configured to supply room-temperature DIW as a rinse liquid, a backside heating unit 25 is provided that discharges high-temperature DIW toward the center of the backside Sb of the substrate S to heat it. The following description of the second embodiment will focus on the differences from the first embodiment, and the same configurations and operations will be denoted by the same or corresponding reference numerals and will not be repeated.

[0082] The backside heating unit 25 has a lower nozzle 251. As shown in FIG. 8 , the lower nozzle 251 has a single outlet 252 facing the center of the backside Sb of the substrate S held by the spin chuck 211. The outlet 252 ejects high-temperature DIW vertically upward. The ejected high-temperature DIW is incident almost perpendicularly on the center of the backside Sb of the substrate S held by the spin chuck 211. A lower-surface supply pipe 253 is connected to the lower nozzle 251. The lower-surface supply pipe 253 is inserted into vertical hollow portions provided in the rotation support shaft 213 and the rotation mechanism 214. A DIW supply source 254 is connected to the lower-surface supply pipe 253. A heater 255 is inserted in the pipe interconnecting the lower-surface supply pipe 253 and the DIW supply source 254. The heater 255 heats the room temperature DIW supplied from the DIW supply source 254 in response to a heating command from the wet process control unit 95 to generate high temperature DIW.

[0083] 9 is a diagram illustrating an overview of processes performed by a substrate processing system according to a second embodiment of the present invention. Similar to the first embodiment, this substrate processing system 1 receives a substrate S to be processed and sequentially performs a wet processing using processing liquids such as chemicals, rinse liquids, and organic solvents, a transfer process in which the wet-processed substrate S is transferred from the wet processing system 2 to the supercritical processing system 4, and a supercritical drying process using a supercritical processing fluid. In the second embodiment, after a predetermined chemical processing is performed by supplying a chemical liquid such as a developer or cleaning liquid in step S21, room-temperature DIW is supplied to the surface Sa of the substrate S as a rinse liquid (step S22A). Subsequently, an organic solvent such as IPA is supplied to the substrate S, replacing the rinse liquid adhering to the surface Sa of the substrate S with the organic solvent (step S23), and creating a puddle of organic solvent. In other words, a liquid film LF is formed on the surface Sa of the substrate S (liquid film formation process). Concurrently with this liquid film formation process, high-temperature DIW is discharged from the outlet 252 of the lower nozzle 251. This high-temperature DIW is incident on the center of the back surface Sb of the substrate S at a substantially normal angle and is supplied to the entire back surface Sb. The supply of this high-temperature DIW to the substrate S heats the inside of the pattern PT. Therefore, as in the first embodiment, convective diffusion of liquid components such as DIW and IPA present in the pattern PT is promoted. In other words, the residual liquid present on the inner bottom surface is also convectively diffused into the IPA and mixed with the IPA. In this way, a residual-liquid-free liquid film LF is formed on the front surface Sa of the substrate S (step S24A).

[0084] The substrate S that has undergone the wet processing is transferred, in a puddle state, from the wet processing apparatus 2 to the supercritical processing apparatus 4 by the substrate transfer apparatus 3 (step S30). Then, in the same manner as in the first embodiment, the supercritical drying process (step S40) is performed in the supercritical processing apparatus 4.

[0085] Therefore, the same effects as those of the first embodiment can be obtained. In this way, in the second embodiment, high-temperature DIW is used to heat the substrate S from the underside, but a fluid other than DIW may be heated and the heated fluid may be supplied to the back surface Sb of the substrate S. In this way, the temperature of the high-temperature DIW and the heating fluid (collectively referred to as the "heating medium") must be 80° C. or higher to heat the inside of the pattern PT. Meanwhile, as in the first embodiment, it is preferable to use a dispense monitor to determine the upper limit temperature of the heating medium at which the liquid film LF can be maintained.

[0086] In the second embodiment described above, the heating of the substrate S by the heating medium corresponds to an example of the "first heating process" of the present invention.

[0087] 10 is a diagram showing an example of the configuration of a wet processing apparatus provided in a substrate processing system according to a third embodiment of the present invention. This substrate processing system 1 differs significantly from the first embodiment in that, instead of supplying room-temperature DIW as a rinse liquid, a heater 26 is built into the spin chuck 211. The following description of the third embodiment will focus on the differences from the first embodiment, and the same or corresponding reference numerals will be used to designate the same configurations and operations, and a description thereof will be omitted.

[0088] The heater 26 is disposed on the spin chuck 211 so that its upper surface faces the entire back surface Sb of the substrate S held on the spin chuck 211. The heater 26 is electrically connected to the wet processing control unit 95. The heater 26 is activated by power supplied from the wet processing control unit 95. This causes the substrate S to be uniformly heated by conductive heat and radiant heat from the upper surface of the spin chuck 211. As a result, the inside of the pattern PT is heated.

[0089] FIG. 11 is a diagram illustrating an overview of processes performed by a substrate processing system according to a third embodiment of the present invention. Similar to the first embodiment, this substrate processing system 1 receives a substrate S to be processed and sequentially performs wet processing using processing liquids such as chemicals, rinse liquids, and organic solvents, a transfer process in which the wet-processed substrate S is transferred from the wet processing system 2 to the supercritical processing system 4, and a supercritical drying process using a supercritical processing fluid. In the third embodiment, after a predetermined chemical processing is performed by supplying chemicals such as a developer or cleaning liquid in step S21, room-temperature DIW is supplied to the surface Sa of the substrate S as a rinse liquid (step S22A). Subsequently, an organic solvent such as IPA is supplied to the substrate S, replacing the rinse liquid adhering to the surface Sa of the substrate S with the organic solvent (step S23), and creating a puddle of organic solvent. In other words, a liquid film LF is formed on the surface Sa of the substrate S (liquid film forming process). Concurrently with this liquid film forming process, the heater 26 is operated to heat the substrate S from below. This heats the inside of the pattern PT. Therefore, as in the first embodiment, convection diffusion of liquid components such as DIW and IPA present in the pattern PT is promoted. That is, the residual liquid present on the inner bottom surface is also convection-diffused into the IPA and mixed with the IPA. In this way, a residual-liquid-free liquid film LF is formed on the surface Sa of the substrate S (step S24B).

[0090] The substrate S that has undergone the wet processing is transferred, in a puddle state, from the wet processing apparatus 2 to the supercritical processing apparatus 4 by the substrate transfer apparatus 3 (step S30). Then, in the same manner as in the first embodiment, the supercritical drying process (step S40) is performed in the supercritical processing apparatus 4.

[0091] Therefore, the same effects as those of the first embodiment can be obtained. In this way, in the third embodiment, the substrate S is heated by the heater 26 disposed below and apart from the substrate S, which corresponds to an example of the "second heating process" of the present invention. Of course, the second heating process may be performed with the heater facing and in close contact with the back surface Sb of the substrate S.

[0092] Furthermore, in the first to third embodiments, the inside of the pattern PT is heated in the wet treatment apparatus 2, but the inside of the pattern PT of the substrate S may be heated while the substrate is being transported to the supercritical treatment apparatus 4 by the substrate transport apparatus 3 (step S30). For example, the hand 31 of the transport robot 30 may be configured to have a built-in heater (not shown), and the inside of the pattern PT may be heated by heating the substrate S with the heater (fourth embodiment).

[0093] Furthermore, the supercritical processing apparatus 4 may be configured to heat the inside of the pattern PT of the substrate S supported on the tray member 416 before the processing fluid is brought into contact with the substrate S. For example, the tray member 416 of the supercritical processing apparatus 4 may be configured to have a built-in heater (not shown), and the inside of the pattern PT may be heated by heating the substrate S with the heater (fifth embodiment).

[0094] Furthermore, in the first to fifth embodiments, the chuck pins 212 have a vibration-imparting function in addition to the function of clamping the side edges of the substrate S to hold the substrate S. Therefore, a step of imparting vibration to the substrate S may be added to each of the first to fifth embodiments after the liquid film formation process (steps S24, S24A, S24B) and before the substrate transport (step S30). Here, a fourth embodiment in which a configuration for imparting vibration is added to the first embodiment will be described with reference to FIG. 12 . The same applies to the other second to fifth embodiments.

[0095] FIG. 12 is a diagram illustrating an outline of a process executed by a substrate processing system according to a fourth embodiment of the present invention. In the fourth embodiment, after a puddle state is created in the wet processing apparatus 2, the wet processing control unit 95 issues a reciprocating movement command to the chuck driver 215. Then, the chucked state shown in FIG. 3( a) and the non-chucked state shown in FIG. 3( b) are alternately repeated. That is, the substrate S is repeatedly raised and lowered in association with the reciprocating movement of the chuck pins 212 in the radial direction D. As a result, as shown in the lower left diagram of FIG. 12, vibrations are applied to the substrate S in the vertical direction Z, causing the DIW and IPA to advect and diffuse. In this way, the residual liquid (DIW) disappears in a shorter time than in the first embodiment, and the DIW spreads over the entire liquid film LF (step S60). In this specification, the process of removing the residual liquid by applying vibrations is referred to as a "residual liquid removal process."

[0096] Furthermore, in the fourth embodiment, a vibration-imparting function is essential for performing the residual liquid removal process, but this function is performed by the chuck pins 212. Therefore, there is no need to add a component that specializes in the vibration-imparting function, and therefore the cost of the device can be reduced.

[0097] Furthermore, in the fourth embodiment, the substrate S is vibrated in the vertical direction Z to perform the residual liquid removal process, but the manner in which vibration is applied is not limited to this. For example, the wet process control unit 95 may issue a forward / reverse rotation command to the rotation mechanism 214 while the substrate S is held by the chuck pins 212. In this case, upon receiving the forward / reverse rotation command, the rotation mechanism 214 rotates the substrate S forward and reverse by a predetermined angle around the rotation axis AX, i.e., repeats a rotation operation. In this way, vibrations may be applied to the substrate S by rotating the substrate S in the circumferential direction.

[0098] Alternatively, vibration may be applied to the substrate S by a separate additional component, without applying vibration along the vertical direction Z by the chuck pins 212 (hereinafter referred to as "vertical vibration") or vibration along the circumferential direction by the rotation mechanism 214 (hereinafter referred to as "rotational vibration"). For example, following the liquid film formation process (step S24), the wet process control unit 95 may activate an ultrasonic vibrator installed at a position distant from the substrate holding unit 21 to vibrate the substrate S with ultrasonic waves generated by the ultrasonic vibrator. Alternatively, the vibrator may be attached to the substrate holding unit 21 in advance, and the wet process control unit 95 may activate the vibrator following the liquid film formation process (step S24). In these embodiments, the vibration direction of the substrate S can be controlled by the installation mode of the vibrator. Conventionally known vibrators and ultrasonic vibrators may be used. Therefore, detailed configuration descriptions will be omitted in this specification.

[0099] Furthermore, in the fourth embodiment, vibrations are applied to the substrate S in a puddle state in the wet treatment apparatus 2, but vibrations may also be applied in the substrate transfer apparatus 3 or the supercritical treatment apparatus 4. For example, in the first and fourth embodiments, the transfer robot 30 is capable of moving forward and backward relative to both the wet treatment apparatus 2 and the supercritical treatment apparatus 4 while supporting the substrate S in a puddle state from the underside. Therefore, the transfer robot 30 not only functions to load and unload the substrate S into and from each of the wet treatment apparatus 2 and the supercritical treatment apparatus 4, but also can horizontally reciprocate and rotate the hand 31 supporting the substrate S. In other words, repeated reciprocal movement and rotation of the hand 31 makes it possible to apply vibrations to the substrate S in the horizontal direction. Therefore, the transfer control unit 96 may control the transfer robot 30 so that the transfer process (step S30) from the wet treatment apparatus 2 to the supercritical treatment apparatus 4 is performed in the following order: a process in which the hand 31 receives the substrate S in a puddled state; a process in which the hand 31, while holding the substrate S in a puddled state, moves back and forth a predetermined distance in a horizontal plane or rotates forward and backward to impart vibration to the substrate S; and a process in which the substrate S in a puddled state is transferred to the processing unit 41 of the supercritical treatment apparatus 4. Note that, although the residual liquid removal process is performed here when the hand 31 enters the wet treatment apparatus 2 and receives the substrate S in a puddled state, the timing of performing the residual liquid removal process is not limited to this. For example, the residual liquid removal process may be performed while the hand 31 is moving to the supercritical treatment apparatus 4 or while the hand 31 is stopped and waiting near the supercritical treatment apparatus 4.

[0100] Furthermore, in order to wait for the transfer of the substrate S to the supercritical processing apparatus 4 depending on the operating status of the supercritical processing apparatus 4, a standby position other than the standby position set near the supercritical processing apparatus 4 as described above may be provided. For example, if the substrate transfer apparatus 3 has a mounting table on which the substrate S in a puddle state is temporarily placed and waited, the mounting table functions as the standby position. Therefore, a vibrator may be attached to the mounting table to impart vibration to the substrate S waiting on the mounting table. In other words, the residual liquid removal process may be performed at the standby position where the mounting table is provided.

[0101] Furthermore, to perform the residual liquid removal process, the hand 31 is vibrated in the horizontal direction or rotated within a horizontal plane, but vibration may be applied in another manner depending on the configuration of the transport robot 30. For example, the transport robot 30 may be configured to be able to move the hand 31 in the vertical direction Z. In such a case, the hand 31 holding the substrate S in a puddle state may be raised and lowered in the vertical direction Z to vibrate the substrate S.

[0102] In the first and fourth embodiments, the substrate S transported to the supercritical processing apparatus 4 is accommodated in the processing chamber 412 in a puddle state. Specifically, the substrate S is transported with the pattern-formed surface Sa facing up, and with the pattern-formed surface Sa covered with a thin liquid film LF. As shown by the dotted line in FIG. 4, the lift pins 437 rise with the lid member 413 moving to the (-Y) side and the support tray 415 pulled out. The transport device delivers the substrate S to the lift pins 437. The lift pins 437 descend, and the substrate S is placed on the support tray 415. In this way, the reception of the substrate S is completed.

[0103] At this point, the supercritical processing control unit 97 may reciprocate the support tray 415 and the lid member 413 along the Y direction while holding the substrate S in a puddle state. This reciprocating movement applies vibration to the substrate S, thereby advection-diffusing the residual liquid (residual liquid removal process), as in the fourth embodiment. According to this embodiment, the residual liquid removal process is performed in the supercritical processing apparatus 4 before the processing fluid in a supercritical state is brought into contact with the substrate S. Therefore, the same effects as those of the fourth embodiment can be obtained.

[0104] Furthermore, in this embodiment, the support tray 415 and the lid member 413 are vibrated in the Y direction to perform the residual liquid removal process, but a vibrator may be attached to the support tray 415 or the lid member 413. In other words, the vibrator may be activated in response to a vibration command from the supercritical process control unit 97 to vibrate the substrate S.

[0105] Although the residual liquid removal process is performed before the pressure in the processing chamber 412 increases, it may also be performed while the pressure is increasing, provided that the pressure does not reach supercritical conditions. For example, the residual liquid removal process may be performed in a subcritical state. In particular, considering the elapsed time between the execution of the residual liquid removal process and the start of contact with the processing fluid in a supercritical state, it is preferable to perform the residual liquid removal process at a timing close to the subcritical state. In other words, due to the fact that the specific gravity of DIW is greater than that of IPA, as the elapsed time increases, some of the DIW that has diffused into the IPA may settle on the inner bottom surface of the pattern PT, increasing the DIW concentration. It is preferable to set the timing of the residual liquid removal process taking this into consideration.

[0106] The present invention is not limited to the above-described embodiment, and various modifications other than those described above are possible without departing from the spirit of the present invention. In the above-described embodiment, when performing the wet processing and supercritical drying processing on one substrate S, the residual liquid removal processing is performed only once, but the residual liquid removal processing may be performed multiple times. In other words, at least one of the first vibration applying processing to the third vibration applying processing may be performed.

[0107] Furthermore, the various chemical substances used in the treatment of the above-described embodiments are only examples, and various substances can be used instead as long as they are consistent with the technical concept of the present invention described above.

[0108] While the invention has been described with reference to specific embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as other embodiments of the invention, will become apparent to those skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover such modifications or embodiments within the true scope of the invention.

[0109] The present invention can be generally applied to a substrate processing method and a substrate processing system in which a substrate covered with a liquid film is processed with a processing fluid in a supercritical state.

[0110] REFERENCE SIGNS LIST 1...substrate processing system 2...wet processing apparatus 3...substrate transfer apparatus 4...supercritical processing apparatus 9...controller 21...substrate holder 30...transfer robot 31...hand 95...wet processing controller 96...transfer controller 97...supercritical processing controller 212...chuck pin 415...support tray AX...rotation axis D...radial direction LF...liquid film PT...pattern S...substrate Sa...upper surface (pattern formation surface) Z...vertical direction

Claims

1. A substrate processing method for processing a substrate having a pattern-formed surface on which a pattern is formed, comprising: (a) a step of performing, in a wet processing apparatus, a wet processing of the substrate by supplying a chemical liquid to the pattern-formed surface, a rinsing processing by supplying a rinsing liquid to the pattern-formed surface, a replacement processing by supplying an organic solvent to the pattern-formed surface, and a puddle processing for forming a liquid film of the organic solvent in a puddle state on the pattern-formed surface by supplying the organic solvent to the pattern-formed surface, in this order; (b) a step of transporting the substrate from the wet processing apparatus to a supercritical processing apparatus while maintaining the puddle state; and (c) a step of drying the substrate in the supercritical processing apparatus by contacting the pattern-formed surface in the puddle state with a processing fluid in a supercritical state, wherein the substrate processing method is characterized in that in at least one of the steps (a), (b) and (c), the inside of the pattern is heated while maintaining the puddle state.

2. A substrate processing method according to claim 1, wherein the rinsing liquid used in the step (a) has a temperature of 40° C. or higher and is equal to or lower than the upper limit temperature at which a puddle state can be maintained.

3. A substrate processing method according to claim 1, wherein the step (a) includes a first heating process for supplying a heating medium to the underside of the substrate opposite the pattern forming surface in parallel with the puddle process.

4. A substrate processing method according to claim 3, wherein the heating medium has a temperature of 80° C. or higher and a maximum temperature at which a puddle state can be maintained.

5. A substrate processing method as claimed in claim 1, wherein the step (a) includes a second heating process in which the substrate is heated by a heater arranged opposite the underside of the substrate opposite the pattern forming surface, in parallel with the puddle process.

6. A substrate processing method as claimed in claim 1, wherein step (b) comprises: (b-1) receiving the substrate from the wet-treatment device with a hand of a transport robot; (b-2) moving the hand to the supercritical treatment device while heating the substrate received from the wet-treatment device with a heater provided on the hand; and (b-3) transferring the substrate from the hand to the supercritical treatment device.

7. A substrate processing method as recited in claim 1, wherein step (c) comprises: (c-1) placing the substrate on a support tray; (c-2) horizontally moving the support tray with the substrate placed thereon to accommodate the substrate in a supercritical processing chamber; (c-3) increasing the pressure inside the processing chamber accommodating the substrate; (c-4) bringing the processing fluid in the supercritical state into contact with the substrate in the processing chamber to perform supercritical drying; and (c-5) heating the substrate by a heater provided on the support tray between steps (c-1) and (c-4).

8. A substrate processing method according to any one of claims 1 to 7, further comprising the step of: (d) vibrating the substrate while maintaining the puddle state, before contacting the processing fluid in the supercritical state with the pattern-forming surface, thereby mixing the rinsing liquid remaining in the pattern with the organic solvent.

9. A substrate processing system for processing a substrate having a pattern-formed surface on which a pattern is formed, comprising: a wet processing apparatus which performs, in the order of: wet processing of the substrate by supplying a chemical liquid to the pattern-formed surface; rinsing processing by supplying a rinsing liquid to the pattern-formed surface; replacement processing by supplying an organic solvent to the pattern-formed surface; and puddle processing for forming a liquid film of the organic solvent in a puddle state on the pattern-formed surface by supplying the organic solvent to the pattern-formed surface; a supercritical processing apparatus which dries the substrate by bringing a processing fluid in a supercritical state into contact with the pattern-formed surface in the puddle state; and a substrate transport apparatus which transports the substrate from the wet processing apparatus to a supercritical processing apparatus while maintaining the puddle state, wherein at least one of the wet processing apparatus, the substrate transport apparatus and the supercritical processing apparatus heats the inside of the pattern while maintaining the puddle state.

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