JP2024079114A - METHOD FOR CLEANING PROCESSING CHAMBER AND SUBSTRATE PROCESSING SYSTEM - Patent application - Google Patents

Abstract

[Problem] To provide a technology capable of effectively cleaning the inside of a supercritical processing chamber having a processing space with a narrow opening and a deep depth. [Solution] This invention is a method for cleaning a processing chamber in a supercritical processing apparatus in which a support part supporting a substrate is accommodated in the processing space of the processing chamber and the substrate is processed in the processing space with a processing fluid in a supercritical state. The method for cleaning a processing chamber according to the present invention comprises the steps of supporting a flat-plate-shaped container that stores a cleaning liquid by the support part and accommodating the support part in the processing space, filling the processing space with the processing fluid in a supercritical state, and discharging the processing fluid. [Selected Figure] Figure 5

Description

This invention relates to a technology for cleaning the inside of a processing chamber of a supercritical device that contains a substrate in the internal processing space and performs supercritical processing.

Processing processes for various substrates, such as semiconductor substrates and glass substrates for display devices, include treating the substrate surface with various processing fluids. Processing using liquids such as chemicals and rinsing liquids as processing fluids has been widely used in the past, but in recent years, processing using supercritical fluids has also been put to practical use. In particular, when processing substrates with fine patterns formed on their surfaces, supercritical fluids, which have lower surface tension than liquids, can penetrate deep into the gaps in the patterns, making processing more efficient and reducing the risk of pattern collapse due to surface tension during drying.

For example, Patent Document 1, previously disclosed by the applicant of the present application, describes a substrate processing apparatus that uses a supercritical fluid to perform a drying process on a substrate. In this substrate processing apparatus, the substrate to be processed is placed on a flat tray and housed in a supercritical processing chamber. The supercritical processing chamber, which is formed by combining multiple metal blocks, has a slit-shaped opening extending horizontally on the side, and a processing space that communicates with the opening and houses the tray inside is formed. In order to reduce the amount of processing fluid used, the size of the processing space is kept to a level slightly larger than the external size of the tray. In other words, the processing space viewed from the opening is narrow in the vertical direction, but long in the horizontal direction and has a deep depth.

JP 2021-163916 A

As processing is repeated, it is inevitable that contaminants will accumulate inside the processing chamber, and therefore the inside of the processing chamber must be cleaned periodically. However, as described above, the processing space in the prior art is a deep space with a slit-like opening, and manual cleaning by an operator is not easy. However, since the processing chamber in the prior art described above is made up of multiple blocks, it is possible to disassemble it and clean the inside.

However, each block is designed to withstand high pressure and is heavy, making it unsuitable for frequent cleaning. For this reason, there is a demand for technology that allows for frequent and effective cleaning of processing chambers with narrow openings and deep processing spaces, as described above, but such technology has not yet been established.

This invention was developed in consideration of the above problems, and aims to provide a technology that can effectively clean the inside of a supercritical processing chamber, even if the chamber has a narrow opening and a deep processing space.

One aspect of the invention is a method for cleaning a processing chamber in a supercritical processing apparatus in which a support part supporting a substrate is accommodated in a processing space of a processing chamber and the substrate is processed in the processing space with a processing fluid in a supercritical state. This aspect includes a step of supporting a flat-plate-shaped container that stores a cleaning liquid by the support part and accommodating the support part in the processing space, a step of filling the processing space with the processing fluid in a supercritical state, and a step of discharging the processing fluid.

Another aspect of the present invention is a method for cleaning a processing chamber in a substrate processing system including a wet processing apparatus that processes a substrate by supplying a processing liquid to the substrate, a supercritical processing apparatus that accommodates a support part supporting the substrate in a processing space of a processing chamber and processes the substrate in the processing space with a processing fluid in a supercritical state, and a transport device that transports the substrate from the wet processing apparatus to the supercritical processing apparatus. This aspect includes a step of storing a cleaning liquid in a flat-plate-shaped container by the wet processing apparatus, a step of transporting the container by the transport device and supporting it on the support part, and a step of accommodating the support part in the processing space by the supercritical processing apparatus, filling the processing space with the processing fluid in a supercritical state, and then discharging the processing fluid.

In addition, one aspect of the present invention is a substrate processing system including a wet processing apparatus that supplies a processing liquid to a substrate to process the substrate, a supercritical processing apparatus that accommodates a support part supporting the substrate in a processing space of a processing chamber and processes the substrate in the processing space with a processing fluid in a supercritical state, a transport device that transports the substrate from the wet processing apparatus to the supercritical processing apparatus, and a control unit that controls the wet processing apparatus, the supercritical processing apparatus, and the transport device to perform a cleaning process for cleaning the inside of the processing chamber. Here, the cleaning process is performed by the wet processing apparatus storing a cleaning liquid in a flat-plate-shaped container, the transport device transporting the container and supporting it on the support part, and the supercritical processing apparatus accommodating the support part in the processing space, filling the processing space with the processing fluid in a supercritical state, and then discharging the processing fluid.

In the invention configured in this way, the supercritical processing fluid that fills the processing space distributes the cleaning liquid throughout the processing space under high pressure. This makes it possible to effectively clean the inside of the processing chamber, and more specifically, the wall surfaces that define the processing space. The cleaning liquid is stored in a container, and the support that normally supports the substrate is housed in the processing chamber with the substrate replaced by the container, and the cleaning liquid is brought into the processing space together with the container.

Therefore, there is no need to connect piping or the like for introducing the cleaning liquid to the processing chamber, and the composition of the cleaning liquid can be set as desired. This means that existing processing chambers can be used as is, and excellent cleaning effects can be obtained by using a cleaning liquid with an appropriate composition depending on the purpose and the substances causing the dirt.

As described above, according to the present invention, the cleaning liquid stored in a container and brought into the processing space is spread throughout the processing space by the processing fluid in a supercritical state, making it possible to effectively clean the inside of the processing chamber.

1 is a diagram showing a schematic configuration of a substrate processing system to which the present invention can be applied; 2 is a flowchart showing an outline of a process executed by the substrate processing system. FIG. 2 is a diagram illustrating a configuration example of a wet treatment apparatus. FIG. 2 is a side view showing the configuration of a supercritical processing apparatus. 10 is a flowchart showing the contents of a cleaning process for a processing chamber. 11A and 11B are diagrams showing the structure of a cleaning liquid container and its dimensional relationship with a support tray. 1A to 1C are diagrams illustrating operations in a cleaning process. 1A to 1C are diagrams illustrating operations in a cleaning process. FIG. 13 is a diagram showing another configuration example of a substrate processing system to which the present invention can be applied.

Figure 1 shows the schematic configuration of a substrate processing system to which the present invention can be applied. In order to unify the directions in each of the following figures, an XYZ Cartesian coordinate system is set 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 vertical downward direction.

This substrate processing system 1 is a processing system for supplying a processing liquid to the upper surface of various substrates, such as semiconductor wafers, to wet process the substrates and then drying the substrates, and has a system configuration suitable for carrying out the substrate processing method according to the present invention. That is, the substrate processing apparatus 1 mainly comprises a wet processing apparatus 2, a transport apparatus 3, a supercritical processing apparatus 4, a container stocker 5, and a control unit 9.

The wet processing device 2, the transport device 3, and the supercritical processing device 4 are arranged in this order along the (+X) direction. The main part of the wet processing device 2 is accommodated inside the processing chamber 200, and an opening (not shown) for inserting and removing a substrate is provided on the (+X) side of the processing chamber 200, and a shutter 201 that can be opened and closed is provided for said opening. On the other hand, the main part of the supercritical processing device 4 is accommodated inside the processing chamber 400, and an opening (not shown) for inserting and removing a substrate is provided on the (-X) side of the processing chamber 400, and a shutter 401 that can be opened and closed is provided for said opening.

The wet processing device 2 receives the substrate to be processed and performs a predetermined wet processing. The type of processing is not particularly limited. The transport device 3 transports the substrate after the wet processing out of the wet processing device 2 and loads it into the supercritical processing device 4. The supercritical processing device 4 performs a drying process (supercritical drying process) on the loaded substrate using a processing fluid in a supercritical state. These are installed in a clean room. Therefore, the transport device 3 transports the substrate S in a clean air atmosphere under atmospheric pressure.

The container stocker 5 has the function of storing cleaning liquid containers 50 used when cleaning the inside of the processing chamber of the supercritical processing device 4. The cleaning process of the processing chamber using the cleaning liquid containers 50 will be described in detail later.

The control unit 9 controls the operation of each of these devices to realize predetermined processing. For this purpose, the control unit 9 is equipped with a CPU 91, memory 92, storage 93, and interface 94. 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 the user and external devices. The operation of the devices described below is realized 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.

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

As the "substrate" in this embodiment, various substrates can be applied, such as semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, substrates for FEDs (Field Emission Displays), substrates for optical disks, substrates for magnetic disks, and substrates for magneto-optical disks. In the following, a substrate processing apparatus used primarily for processing disc-shaped semiconductor wafers will be described with reference to the drawings. However, the present invention can be applied to the processing of the various substrates exemplified above in the same manner. Various substrate shapes can also be applied.

Figure 2 is a flow chart showing an overview of the processing performed by this substrate processing system. This substrate processing system 1 receives a substrate S to be processed (Figures 3 and 4) and sequentially performs wet processing using a processing liquid and supercritical drying processing using a supercritical processing fluid. Specifically, the process is as follows. The substrate S to be processed is accommodated in the wet processing device 2 that constitutes the substrate processing system 1 (step S101). The substrate S may be directly carried in by an external transport device, or may be carried in from an external transport means via the transport device 3.

The wet processing device 2 performs wet processing on the substrate S using a predetermined processing liquid (step S102). Then, a liquid film forming process is performed to form a liquid film on the surface using an organic solvent such as IPA (isopropyl alcohol) (step S103). For example, if a fine pattern is formed on the surface of the substrate S, the pattern may collapse due to the surface tension of the liquid remaining on the substrate S. In addition, water marks may remain on the surface of the substrate S due to incomplete drying. Furthermore, the surface of the substrate S may be altered, such as by oxidation, when exposed to the outside air. In order to prevent such problems from occurring, the substrate S may be transported with its surface (pattern-formed surface) covered with liquid.

For example, if the processing liquid is mainly composed of water, the transfer is performed with a liquid having a lower surface tension and being less corrosive to the substrate, such as an organic solvent such as IPA or acetone, forming a liquid film. That is, the substrate S is supported horizontally and with a liquid film formed on its upper surface, and is transferred by the transfer device 3 out of the wet processing device 2 (step S104), and is further transferred and finally transferred into the supercritical processing device 4 (step S105).

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

The supercritical processing fluid is vaporized and discharged without passing through a liquid phase. The liquid adhering to the substrate S is replaced by the supercritical processing fluid and discharged, and the processing fluid is also discharged, resulting in a dry substrate S. Since no gas-liquid interface is formed in this process, it is possible to avoid pattern collapse due to surface tension. After processing, the substrate S is transported out of the supercritical processing device 4 by the transport device 3 and handed over to a subsequent process (step S107). The content of the subsequent process is optional.

The structure of each component of the substrate processing system 1 for performing the above-mentioned series of processes will now be described in more detail.

The transport device 3 is provided with a center robot 30 having a hand 31 attached to the tip of an extendable and rotatable arm (not shown). As indicated by the dashed arrow, the center robot 30 is rotatable around the Z axis. The hand 31 can support a substrate by partially contacting the underside of the substrate. As indicated by the dotted line in FIG. 1, the hand 31 is stored inside the cover 32, and can be moved forward and backward relative to each of the wet treatment device 2, the supercritical device 4, and the container stocker 5 by advancing from the cover 32 to the outside as necessary. This allows substrates to be loaded and unloaded from each of the wet treatment device 2 and the supercritical device 4. The operation of the center robot 30 is controlled by the transport control unit 96 of the control unit 9.

In addition, the center robot 30 accesses the container stocker 5 in response to a control command from the transport control unit 96, and transports the cleaning liquid container 50 out of the container stocker 5 and transports the cleaning liquid container 50 into the container stocker 5.

As a center robot of this type, the one described in JP 2020-188228 A, previously disclosed by the applicant of the present application, can be suitably applied. The specific structure of the center robot 31 can be found in that publication, so a detailed explanation will be omitted here.

Figure 3 is a diagram showing 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 an apparatus 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.

The wet processing device 2 supplies a processing liquid to the upper surface Sa of the substrate S to perform wet processing such as surface treatment and cleaning of the substrate S. For this purpose, the wet processing device 2 is provided with a substrate holding unit 21, a splash guard 22, and processing liquid supply units 23 and 24 inside the processing chamber 200. These operations are controlled by a wet processing control unit 95 provided in the control unit 9.

The substrate holding unit 21 has a disk-shaped spin chuck 211 with a diameter roughly equal to that of the substrate S, and a number of chuck pins 212 are provided on the periphery of the spin chuck 211. The chuck pins 212 abut against the periphery of the substrate S to support the substrate S, allowing the spin chuck 211 to hold the substrate S in a horizontal position while spaced apart from its upper surface.

The spin chuck 211 is supported so that its upper surface is horizontal by a rotating support shaft 213 that extends downward from the center of its lower surface. The rotating support shaft 213 is supported for free rotation by a rotating mechanism 214 attached to the bottom of the processing chamber 200. The rotating mechanism 214 has a built-in 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 directly connected to the rotating support shaft 213 rotates around the vertical axis shown by the dashed dotted line. In FIG. 2, the up-down direction is the vertical direction. As a result, the substrate S is rotated around the vertical axis while remaining in a horizontal position.

The splash guard 22 is provided to surround the substrate holding part 21 from the side. The splash guard 22 has a roughly 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 part 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 by the solid line in FIG. 3, and an upper position where the upper end of the cup 221 is located above the peripheral part of the substrate S as shown by the dotted line in FIG. 3.

When the cup 221 is in the lower position, as shown by the solid line in FIG. 3, the substrate S held by the spin chuck 211 is exposed outside the cup 221. This prevents the cup 221 from becoming an obstacle, for example, when the substrate S is loaded into or unloaded from the spin chuck 211.

When the cup 221 is in the upper position, as shown by the dotted line in FIG. 3, it surrounds the peripheral portion of the substrate S held by the spin chuck 211. This prevents the processing liquid shaken off from the peripheral portion of the substrate S during liquid supply, which will be described later, from scattering inside the processing chamber 200, and makes 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 portion of the substrate S adhere to the inner wall of the cup 221 and flow downward, and are collected and collected by the liquid receiving portion 222 arranged below the cup 221. Multiple stages of cups may be provided concentrically to collect multiple processing liquids individually.

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 that is rotatably mounted on a base 231 fixed to the bottom of the processing chamber 200. The arm 233 swings as the pivot shaft 232 rotates in response to a control command from the control unit 9. This causes the nozzle 234 at the tip of the arm 233 to move between a retracted position retracted to the side from above the substrate S and a processing position above the substrate S.

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 towards the substrate S. The spin chuck 211 rotates at a relatively slow speed to rotate the substrate S, and processing liquid is supplied from the nozzle 234 positioned above the center of rotation of the substrate S, thereby processing the upper surface Sa of the substrate S with the processing liquid. As the processing liquid, liquids having various functions such as a developer, an etching liquid, a cleaning liquid, a rinsing liquid, etc. can be used, and the composition of the liquid is arbitrary. In addition, multiple types of processing liquids may be combined to perform processing.

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 corresponding to 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 delivered from a processing liquid supply source 248 to the upper surface Sa of the substrate S.

In this wet processing apparatus 2, the second processing liquid supply unit 24 is used for the purpose of forming a liquid film to prevent drying on the substrate S after the wet processing. That is, the substrate S after the wet processing is transported to the supercritical processing apparatus 4 and subjected to supercritical drying processing, 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 with its surface covered with a paddle-shaped liquid film.

The liquid that constitutes the liquid film is a substance with a lower surface tension than water, which is the main component of the processing liquid used in wet processing, such as an organic solvent such as isopropyl alcohol (IPA) or acetone.

Here, two sets of processing liquid supply units are provided in the wet processing apparatus 2, but the number of processing liquid supply units installed, 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. Also, one processing liquid supply unit may have multiple nozzles. For example, multiple nozzles may be provided at the tip of one arm. Also, in addition to the above-mentioned mode in which the nozzle is positioned at a predetermined position and the processing liquid is discharged, for example, the nozzle may discharge the processing liquid while moving in a scanning manner along the upper surface Sa of the substrate S. Also, a gas supply unit having a nozzle that discharges gas may be further provided. Also, at least one of the multiple nozzles provided in the processing liquid supply unit may discharge gas.

Figure 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 a processing fluid in a supercritical state, and then discharges the processing fluid, ultimately bringing the substrate S to a dry state.

The supercritical processing apparatus 4 comprises a processing unit 41 and a transfer unit 43 provided in a processing chamber 400, and a supply unit 45. The processing unit 41 is the main body that carries out the supercritical drying process. The transfer unit 43 receives the substrate S after wet processing transported by the transport device 3 and transports it into the processing unit 41, and also transfers the processed substrate S from the processing unit 41 to the transport device 3. The supply unit 45 supplies chemical substances, power, energy, etc. required for processing to the processing unit 41 and the transfer unit 43. These operations are controlled by the control unit 9, in particular the supercritical processing control unit 97.

The processing unit 41 has a structure in which a processing chamber 412 is attached on a pedestal 411. The processing chamber 412 is constructed by combining several metal blocks, and its interior is hollow, forming a processing space SP. The substrate S to be processed is loaded into the processing space SP and processed. A slit-shaped opening 421 that is elongated and extends in the X direction is formed on the (-Y) side surface of the processing chamber 412. The processing space SP communicates with the outside space via the opening 421. The cross-sectional shape of the processing space SP is roughly 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.

A lid member 413 is provided on the (-Y) side of the processing chamber 412 so as to close the opening 421. The lid member 413 closes the opening 421 of the processing chamber 412, thereby forming an airtight processing container. 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 of the lid member 413. The upper surface of the support tray 415 serves as 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 freely movable horizontally in the Y direction.

The lid member 413 can be moved forward and backward relative to the processing chamber 412 by a forward and backward mechanism 453 provided in the supply unit 45. Specifically, the forward and backward mechanism 453 has a linear motion mechanism such as a linear motor, a linear 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 forward and backward mechanism 453 operates in response to a control command from the control unit 9.

When the lid 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 the substrate S placed on the support tray 415. On the other hand, when the lid member 413 moves in the (+Y) direction, the support tray 415 is accommodated in the processing space SP. When 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.

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, and keeps the processing space SP airtight. The seal 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 to seal the processing space SP, and a separated state (dotted line) in which the lid member 413 is significantly separated from the opening 421 to allow the substrate S to be inserted and removed.

With the processing space SP kept airtight, processing of the substrate S is performed in the processing space SP. In this embodiment, the fluid supply section 457 provided in the supply unit 45 delivers a processing fluid of a substance that can be used in supercritical processing, such as carbon dioxide, as the processing fluid, and the processing fluid is pressurized in 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 substance suitable for supercritical drying processing because it reaches a supercritical state at a relatively low temperature and pressure and has the property of dissolving organic solvents that are often 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.

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. The substrate S is then processed by the supercritical fluid in the processing chamber 412. The supply unit 45 is provided with a fluid recovery section 455, and the fluid after processing is recovered by the fluid recovery section 455. The fluid supply section 457 and the fluid recovery section 455 are controlled by the supercritical processing control section 97.

The processing space SP has a shape and volume capable of receiving 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 height of the support tray 415 in the vertical direction, and a depth capable of receiving the support tray 415. In this way, the processing space SP has a shape and volume sufficient to receive 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.

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

The supercritical 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 the results. This appropriately manages the supply of processing fluid to the processing space SP and the discharge of processing fluid from the processing space SP, and adjusts the pressure and temperature in the processing space SP according to a predetermined processing recipe.

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 includes 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 portion 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 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.

The lifting member 433 can be raised and lowered 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 guide, a ball screw mechanism, a solenoid, an air cylinder, etc., 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 unit 9.

The base member 435 moves up and down as the lifting member 433 moves up and down, and the multiple lift pins 437 move up and down integrally with the base member 435. 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. 4, 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 a through hole 417 for inserting the lift pin 437. When the base member 435 rises, the upper end of the lift pin 437 reaches a position higher than the upper surface of the support tray 415 through the through hole 417. In this state, the substrate S transported by the center robot 30 is transferred from the hand 31 of the center robot 30 to the lift pin 437. The lift pin 437 is lowered, and the substrate S is transferred from the lift pin 437 to the support tray 415. The substrate S can be removed by the reverse procedure to the above.

An example of the dimensions of the processing space SP is as follows: For example, if the substrate S is a semiconductor wafer with a diameter of up to 300 mm, the opening height can be 20 to 30 mm, the opening width can be a value slightly larger than 300 mm, and the depth of the processing space SP can be approximately 400 mm.

Regular cleaning of the processing space SP is necessary because dirt accumulates inside as processing is repeated. It is not easy to clean the processing space SP, which has a wide opening, a small height, and a deep depth. Therefore, in this embodiment, instead of physical cleaning, a cleaning liquid is introduced from the outside into the processing space SP to clean the inside of the processing chamber 412, more specifically, the inner wall surface of the processing chamber 412 that constitutes the processing space SP.

Figure 5 is a flow chart showing the contents of the cleaning process for the processing chamber. In the cleaning process of this embodiment, a cleaning liquid container (hereinafter sometimes simply referred to as a "container") 50 prepared for the cleaning process is transferred from the container stocker 5 to the wet processing device 2 by the center robot 30 (step S201). The wet processing device 2 supplies an appropriate cleaning liquid to the cleaning liquid container 50 that has been carried in (step S202). The cleaning liquid container 50 thus storing the cleaning liquid is carried out of the wet processing device 2 by the center robot 30 (step S203) and carried into the processing chamber 412 of the supercritical processing device 4 (step S204).

After the processing space SP is sealed, processing fluid is supplied to the processing space SP from the fluid supply unit 457, and the processing fluid becomes supercritical within the processing space SP. This causes the cleaning liquid to dissolve in the processing fluid, the surface tension of which has been reduced, and the cleaning liquid spreads widely within the processing space SP under high pressure. As a result, the inner wall surface of the processing chamber 412 that constitutes the processing space SP is effectively cleaned (step S205). In this specification, the process of cleaning the inside of the processing chamber 412 by filling the processing space SP into which the cleaning liquid has been introduced with supercritical processing fluid in this manner is sometimes referred to as a "supercritical cleaning process."

After the processing space SP is filled with the supercritical processing fluid for a certain period of time, the processing fluid is discharged from the processing space SP and collected by the fluid recovery unit 455. At this time, contaminants and cleaning fluid that have detached from the inner wall surface of the processing chamber 412 are also discharged together with the processing fluid, thereby cleaning the inside of the processing chamber 412. The cleaning fluid container 50 is pulled out by the movement of the lid member 413 in the (-Y) direction, and the center robot 30 removes the cleaning fluid container 50 and returns it to the container stocker 5 (step S206), completing the cleaning process.

The supply and discharge mode of the processing fluid (carbon dioxide) in the supercritical cleaning process, i.e., the supply and discharge recipe, can be the same as the supply and discharge recipe in the supercritical drying process for the substrate S, for example. This eliminates the need to prepare a special supply and discharge recipe for the cleaning process. For example, a supply and discharge recipe can be applied that combines a supply recipe in which the processing fluid introduced into the processing space SP in gas or liquid phase is pressurized within the processing space SP to reach a supercritical state, and a discharge recipe in which the processing space SP is depressurized to change the phase of the processing fluid from the supercritical state to the gas phase and then discharged.

In the supercritical drying process, the liquid adhering to the substrate S during loading must be replaced with a processing fluid and discharged outside the processing space SP, so the period during which the supercritical state is maintained is set to be relatively long. On the other hand, in the supercritical cleaning process, this period may be shorter. In the supercritical drying process, in order to prevent the collapse of the fine pattern formed on the substrate S, the discharge recipe is set so that the processing fluid is vaporized from the supercritical state without passing through the liquid phase, but in the supercritical cleaning process, there is no need to consider the problem of pattern collapse. Therefore, for example, the processing fluid may be discharged in a liquid phase state. In this way, the cleaning liquid containing the contaminants after processing can be efficiently discharged together with the liquid-phase processing fluid.

Figure 6 shows the structure of the cleaning liquid container and its dimensional relationship with the support tray. As shown in Figure 6 (a), the cleaning liquid container 50 is a flat-plate-shaped container having a roughly disk-shaped outer shape and a flat bottom surface 51 whose outer periphery extends upward to form a side wall surface 52. The space surrounded by this bottom surface 51 and side wall surface 52 functions as a storage space for storing the cleaning liquid. In other words, during the cleaning process, the cleaning liquid is transported into the processing space SP while stored in the storage space of the cleaning liquid container 50.

Although it is possible to introduce the cleaning liquid by forming a liquid film on a flat plate-like member, such as the substrate S, by using such a dedicated container, a larger amount of cleaning liquid can be reliably brought into the processing space SP, thereby improving the cleaning effect. It also prevents the substrate from being consumed for cleaning. The container can also be made of a material that corresponds to the composition of the cleaning liquid.

The outer diameter of the cleaning liquid container 50 is approximately the same as the outer diameter of the substrate S (e.g., 300 mm in diameter). The height is slightly larger than the thickness of the substrate S and is a dimension that can be accommodated without any problems in the processing space SP, and can be, for example, about 1 to 2 mm. The cleaning liquid container 50 can be made of resin material, glass, stainless steel, etc., or it can be made from a silicon wafer cut to the above thickness and machined.

As shown in FIG. 6(a), a recess 415a having a planar size capable of accommodating the substrate S in a horizontal position is formed on the upper surface of the support tray 415. In addition, a plurality of support pins 416 (three in this example) are arranged on the periphery of the recess 415a to hold the substrate S spaced apart from the upper surface of the recess 415a. Therefore, when the substrate S is placed on the support tray 415, as shown in the top view and cross-sectional view in the left column of FIG. 3(b), the substrate S comes into contact with the upper surfaces of the support pins 416, and is accommodated inside the recess 415a and supported in a horizontal position, slightly spaced apart from the upper surface of the recess 415a.

In the cleaning process, a cleaning liquid container 50 is placed on the support tray 415 instead of the substrate S. It is preferable that a notch 53 is provided in the side wall surface 52 of the cleaning container 50 at a position corresponding to the arrangement position of the support pin 416. Then, as shown in the top view and cross-sectional view in the right column of FIG. 6(b), by placing the cleaning liquid container 50 on the support tray 415 with the notch 53 corresponding to the position of the support pin 416, the bottom surface of the cleaning liquid container 50 can be abutted against the upper surface of the recess 415a and accommodated in the recess 415a. With this structure, it is possible to maximize the height of the cleaning liquid container 50 within the range that can be accommodated in the processing space SP, and store more cleaning liquid.

The operation of each part of the apparatus in the above-mentioned cleaning process will be described below with reference to Figures 7 and 8. Figure 7 is a diagram showing the operation of the wet processing apparatus and the center robot in the cleaning process, and Figure 8 is a diagram showing the operation of the supercritical processing apparatus and the center robot in the cleaning process.

In step S201 of the cleaning process, as shown in FIG. 7(a), the hand 31 of the center robot 30 holds and transports an empty cleaning liquid container 50, and places it on the spin chuck 211 of the wet processing device 2. Since the cleaning liquid container 50 has approximately the same diameter as the substrate S, the cleaning liquid container 50 is supported by chuck pins 212 provided on the outer periphery of the spin chuck 211.

From this state, as shown in FIG. 7(b), one of the processing liquid supply units (in this example, the first processing liquid supply unit 23) is activated, and the nozzle 234 moves above the cleaning liquid container 50. Then, as shown in FIG. 7(c), the cleaning liquid Lc is discharged from the nozzle 234 and stored in the storage space of the cleaning liquid container 50 (step S202). After a predetermined amount of cleaning liquid is injected, the cleaning liquid container 50 is again supported by the hand 31 of the center robot 30 and transported out of the wet processing device 2 (step S203), as shown in FIG. 7(d). Note that here, as in the case of wet processing, the cup 221 of the splash guard 22 rises and falls as the processing progresses, but the cup 221 may be positioned at a lower position.

The center robot 30 transports the cleaning liquid container 50 to the supercritical processing device 4. Then, as shown in FIGS. 8(a) and (b), the cleaning liquid container 50 is transferred from the hand 31 to the lift pin 437. As shown in FIG. 8(c), the lift pin 437 descends to place the cleaning liquid container 50 on the support tray 415, and the cover member 413 moves in the (+Y) direction to accommodate the cleaning liquid container 50 together with the support tray 415 in the processing space SP. In this way, the cleaning liquid Lc is carried into the processing space SP in the processing chamber 412 (step S204). Then, the processing fluid is supplied to the processing space SP to be in a supercritical state, thereby cleaning the inside of the processing chamber 412 (step S205). Note that, for the sake of simplicity, FIG. 8 shows the container 50 being placed on the flat upper surface of the support tray 415, but in reality, the container 50 is accommodated in a recess 415a provided on the upper surface of the support tray 415 as shown in FIG. 6(a).

Here, the cleaning liquid Lc is supplied from the first processing liquid supply unit 23 in the wet processing apparatus 2, but a separate processing liquid supply unit specialized for supplying the cleaning liquid Lc may be provided. Also, multiple types of liquid may be supplied from one or multiple processing liquid supply sources, and these may be mixed in the cleaning liquid container 50 to function as the cleaning liquid.

As the cleaning liquid, various substances that dissolve in the processing fluid (carbon dioxide in this example) and exert a cleaning effect can be used. For example, various organic solvents, such as IPA and acetone, can be used to remove organic matter remaining in the processing space SP. For example, if the cleaning liquid Lc is mainly composed of the same type of liquid as the liquid that constitutes the liquid film formed on the substrate S in the supercritical drying process, there is no need to install new piping or supply sources in the wet processing apparatus 2 to inject the cleaning liquid Lc into the cleaning liquid container 50.

Because the cleaning process is performed in the absence of a substrate in the processing space SP, it is possible to introduce a liquid that cannot be used in the presence of a substrate. For example, when a cleaning liquid containing water as the main component is used, the carbonic acid produced by mixing water with carbon dioxide is weakly acidic, and is effective in cleaning and removing water-soluble contaminants as well as inorganic substances such as alkaline metals. If water remains in the piping that supplies various fluids to the processing space SP, it can cause corrosion. For this reason, it is generally not necessarily preferable to connect the piping for supplying water to the processing chamber 412. However, in this embodiment, the cleaning liquid is transported to the processing space SP in a state of being stored in the container 50 without passing through the piping, so the composition of the cleaning liquid can be selected without considering the problem of corrosion.

To improve the cleaning effect, additives such as surfactants may be added to the cleaning liquid. For the same purpose, the cleaning liquid may be heated to an appropriate liquid temperature. The cleaning liquid does not necessarily need to be injected into the cleaning liquid container 50 by the wet processing device 2. However, if a wet processing device 2 having the function of supplying various processing liquids for processing the substrate S is used, it is possible to precisely adjust the composition and liquid temperature of the cleaning liquid Lc stored in the container 50, making it possible to obtain good and stable cleaning effects.

The cleaning process is preferably performed periodically at a predetermined interval while multiple substrates S are being processed sequentially. For example, the cleaning process can be performed every time the number of processed substrates S reaches a specified value. In addition, the cleaning process may be performed prior to a change in the type of substrate S to be processed.

The substrate processing system 1 of the above embodiment includes one wet processing device 2 and one supercritical processing device 4. However, other substrate processing systems may include multiple of each of these. The present invention can also be applied to such substrate processing systems.

Figure 9 shows another example of the configuration of a substrate processing system to which the present invention can be applied. This substrate processing system 12 includes two wet processing apparatuses 2A and 2B and two supercritical processing apparatuses 4A and 4B. These may also be stacked in multiple stages in the Z direction.

The two wet processing apparatuses 2A and 2B each have the same configuration as the wet processing apparatus 2 described above. The two supercritical processing apparatuses 4A and 4B each have the same configuration as the supercritical processing apparatus 4 described above. A center robot 30 is provided in the space surrounded by these. The configuration and functions of these are the same as those of the above embodiment, so a description thereof will be omitted.

An indexer unit 6 is provided on the (-X) side of these processing devices. The indexer unit 6 includes a container holder 61 capable of holding multiple storage containers C (FOUPs (Front Opening Unified Pods), SMIF (Standard Mechanical Interface) pods, OCs (Open Cassettes), etc., which contain multiple substrates S in a sealed state) for containing substrates S, and an indexer robot 62 for accessing the storage containers C held by the container holder 61 to remove unprocessed substrates S from the container C and store processed substrates in the storage container C. Each storage container C contains multiple substrates S in a substantially horizontal position.

The indexer robot 62 comprises a base 621 fixed to the device housing, a multi-joint arm 622 rotatable about a vertical axis relative to the base 621, and a hand 623 attached to the tip of the multi-joint arm 622. The hand 623 is structured so that a substrate S can be placed on its upper surface and held thereon. Indexer robots having such multi-joint arms and hands for holding substrates are well known, so a detailed description will be omitted.

In this substrate processing system 12, an unprocessed substrate S stored in a storage vessel C is removed by an indexer robot 62, which then transfers the substrate S to a center robot 30. The processing of the substrate S is as described above, but since there are multiple wet processing devices and multiple supercritical processing devices, the access destination of the center robot 30 changes as needed.

After processing, the substrate S is transferred from the center robot 30 to the indexer robot 62, which then stores the substrate S in the storage container C. In this manner, the substrates S held in the storage container C are processed sequentially.

A container stocker 5A is provided on the (+X) side of the center robot 30, and the cleaning liquid container 50 is stored in this container stocker 5A. Then, when a cleaning process is performed as necessary, the center robot 30 takes out the cleaning liquid container 50 from the container stocker 5A and transports it sequentially to the wet processing device 2A, etc. and the supercritical processing device 4A, etc., in the same manner as described above. Only one cleaning liquid container 50 may be provided, or multiple cleaning liquid containers 50 may be provided. For example, the same number of cleaning liquid containers 50 as the number of pairs of wet processing devices and supercritical processing devices may be prepared. Furthermore, when these devices are stacked in multiple layers, the same number of cleaning liquid containers 50 as the number of layers may be prepared.

As described above, in the above embodiment, the substrate processing system 1 including the wet processing device 2, the transport device 3 (center robot 30), the supercritical processing device 4, the container stocker 5, and the control unit 9, and the substrate processing system 12 including the wet processing device 2A, 2B, the center robot 30, the supercritical processing device 4A, 4B, the cleaning liquid stocker 5A, and the control unit 9 each correspond to the "substrate processing system" of the present invention. In addition, the cleaning liquid container 50 functions as the "container" of the present invention, and the container stockers 5, 5A function as the "stocker" of the present invention. In addition, the support tray 415 functions as the "support unit" of the present invention.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the cleaning process of the above embodiment, a supercritical cleaning process is performed once using one type of cleaning liquid. However, if necessary, multiple supercritical cleaning processes may be performed using the same type of cleaning liquid, or multiple supercritical cleaning processes may be performed using different types of cleaning liquid. Furthermore, an appropriate pre-process or post-process may be added before or after the supercritical cleaning process.

The processing chamber 412 of the supercritical processing apparatus 4 described above has a slit-shaped opening on its side with the horizontal direction as the longitudinal direction. However, the cleaning process according to the present invention is not limited to the structure and opening shape of such a processing chamber, and can be applied to a variety of things. For example, the cleaning method of the present invention can be applied to a processing chamber that has a relatively large opening and can be cleaned manually.

The various chemical substances used in the processes of the above embodiments are only a few examples, and various substances can be used instead as long as they are in accordance with the technical concept of the present invention.

As described above by way of example of specific embodiments, in the method for cleaning a processing chamber according to the present invention, the cleaning liquid can be mainly composed of the same type of liquid as the liquid that adheres to the substrate when the substrate is accommodated in the processing space. Since such a liquid is selected to dissolve well in the processing fluid, by using the same type of liquid for the cleaning liquid, the cleaning liquid can be distributed throughout the entire processing space, and an excellent cleaning effect can be obtained.

For example, if the cleaning fluid contains water, water-soluble contaminants can be effectively removed. In particular, if the treatment fluid is carbon dioxide, the carbon dioxide produced by mixing water with carbon dioxide is weakly acidic, providing an excellent cleaning effect against alkaline dirt.

For example, the cleaning solution may be pre-heated. This can further improve the cleaning effect.

For example, the processing space may be filled with processing fluid by applying a supply recipe used to supply processing fluid to the processing space for processing a substrate. In this way, there is no need to prepare a special recipe for cleaning the processing chamber. In other words, cleaning of the processing chamber can be achieved by the same process as performing supercritical processing on the substrate.

The substrate processing system according to the present invention may also be provided with a stocker for temporarily holding the container. When processing the substrate, a container for storing the cleaning liquid is not required. By providing a stocker for storing the container, the transport device does not need to hold the container, and it is possible to process the substrate and clean the processing chamber at the same time.

This invention can be applied to the general substrate processing technology in which a substrate is processed in a supercritical processing chamber. In particular, it can be suitably applied to the purpose of cleaning the inside of a supercritical processing chamber for performing a substrate drying process in which a substrate such as a semiconductor substrate is dried using a supercritical fluid.

1, 12 Substrate processing system 2, 2A, 2B Wet processing apparatus 3 Transfer apparatus 4, 4A, 4B Supercritical processing apparatus 5, 5A Container stocker (stocker)
9 Control unit 30 Transport robot 31 Hand 50 Cleaning liquid container (container)
412 Processing chamber 415 Support tray (support part)
S Substrate SP Processing space

Claims (8)

1. A method for cleaning a processing chamber in a supercritical processing apparatus in which a support supporting a substrate is accommodated in a processing space of a processing chamber, and the substrate is processed in the processing space with a processing fluid in a supercritical state, comprising:
a step of supporting a dish-shaped container containing a cleaning liquid by the support part and housing the support part in the processing space;
filling the processing space with the processing fluid in a supercritical state;
and draining the processing fluid. A method for cleaning a processing chamber in a substrate processing system including a wet processing apparatus for supplying a processing liquid to a substrate to process the substrate, a supercritical processing apparatus for accommodating a support part supporting the substrate in a processing space of a processing chamber and processing the substrate with a processing fluid in a supercritical state in the processing space, and a transfer apparatus for transferring the substrate from the wet processing apparatus to the supercritical processing apparatus, comprising:
storing a cleaning liquid in a flat-plate-shaped container by the wet treatment device;
a step of transporting the container by the transport device and supporting the container on the support part;
using the supercritical processing apparatus to accommodate the support part in the processing space, fill the processing space with the processing fluid in a supercritical state, and then discharge the processing fluid. The method for cleaning a processing chamber according to claim 1 or 2, wherein the cleaning liquid is mainly composed of the same type of liquid as that which adheres to the substrate when the substrate is accommodated in the processing space. The method for cleaning a processing chamber according to claim 1 or 2, wherein the cleaning liquid includes water. The method for cleaning a processing chamber according to claim 1 or 2, wherein the cleaning liquid is preheated. The method for cleaning a processing chamber according to claim 1 or 2, wherein the processing space is filled with the processing fluid by applying a supply recipe for supplying the processing fluid to the processing space to process the substrate. a wet processing apparatus for supplying a processing liquid to a substrate to process the substrate;
a supercritical processing apparatus that accommodates a support that supports the substrate in a processing space of a processing chamber and processes the substrate in the processing space with a processing fluid in a supercritical state;
a transport device that transports the substrate from the wet treatment device to the supercritical treatment device;
a control unit that controls the wet treatment device, the supercritical treatment device, and the transfer device to perform a cleaning process for cleaning the inside of the treatment chamber, the cleaning process comprising:
The wet treatment device stores a cleaning liquid in a flat dish-shaped container,
the conveying device conveys the container and supports it on the support portion;
the supercritical processing apparatus accommodates the support part in the processing space, fills the processing space with the processing fluid in a supercritical state, and then discharges the processing fluid;
The substrate processing system according to claim 1, The substrate processing system according to claim 7, further comprising a stocker for temporarily holding the container.

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