SUBSTRATE TRANSFER APPARATUS AND SUBSTRATE TRANSFER METHOD

An apparatus for transferring a substrate to a substrate processing chamber is provided. The apparatus comprises: a substrate transfer chamber having a floor provided with a first magnet and a sidewall connected to the substrate processing chamber and having an opening through which a substrate is loaded into and unloaded from the substrate processing chamber; a substrate transfer module including a substrate holder configured to hold the substrate and a second magnet having a repulsive force against the first magnet, and configured to move in the substrate transfer chamber by magnetic levitation using the repulsive force; and a heating device configured to heat the substrate transfer module to release contaminants adhered to a surface of the substrate transfer module.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2021-180835 filed on Nov. 5, 2021, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a substrate transfer apparatus and a substrate transfer method.

BACKGROUND

For example, in an apparatus (wafer processing apparatus) for processing a semiconductor wafer (hereinafter, also referred to as “wafer”) that is a substrate, a wafer is transferred between a carrier accommodating wafers and a wafer processing chamber for processing a wafer. Various types of wafer transfer mechanisms are used for transferring wafers.

The applicants of the present disclosure are developing a wafer processing apparatus for transferring a substrate using a substrate transfer module that utilizes magnetic levitation.

In the wafer processing apparatus, small amounts of various contaminants such as particles generated by the contact between a wafer and a device or between devices, chemical substances used during wafer processing, and the like exist in a space where a wafer is transferred. When these contaminants are adhered to and accumulated on the substrate transfer module, a wafer to be transferred is contaminated.

For example, Japanese Laid-open Patent Publication No. 2005-101539 discloses a technique for increasing temperatures of members constituting a stage on which a substrate to be processed is placed and the like in a decompression processing apparatus and scattering particles by thermal stress and thermophoretic force. On the other hand, Japanese Laid-open Patent Publication No. 2005-101539 does not disclose a method for dealing with the contamination of the substrate transfer module that utilizes magnetic levitation.

SUMMARY

The present disclosure provides a technique for cleaning a substrate transfer module that utilizes magnetic levitation to transfer a substrate.

In accordance with one aspect of the present disclosure, an apparatus for transferring a substrate to a substrate processing chamber is provided. The apparatus comprises: a substrate transfer chamber having a floor provided with a first magnet and a sidewall connected to the substrate processing chamber and having an opening through which a substrate is loaded into and unloaded from the substrate processing chamber; a substrate transfer module including a substrate holder configured to hold the substrate and a second magnet having a repulsive force against the first magnet, and configured to move in the substrate transfer chamber by magnetic levitation using the repulsive force; and a heating device configured to heat the substrate transfer module to release contaminants adhered to a surface of the substrate transfer module.

DETAILED DESCRIPTION

Hereinafter, a configuration of an apparatus for transferring a substrate according to an embodiment of the present disclosure will be described with reference toFIG.1. The apparatus for transferring a substrate is disposed in a wafer processing system101.

FIG.1shows the multi-chamber type wafer processing system101including a plurality of wafer processing chambers110that are substrate processing chambers for processing wafers W. As shown inFIG.1, the wafer processing system101includes load ports141, an atmospheric transfer chamber140, load-lock chambers130, a vacuum transfer chamber160, and the plurality of wafer processing chambers110. In the following description, a side on which the load ports141are arranged is set to a front side.

In the wafer processing system101, the load ports141, the atmospheric transfer chamber140, the load-lock chambers130, and the vacuum transfer chamber160are arranged in a horizontal direction in that order from the front side. The plurality of wafer processing chambers110are arranged side by side on the left and right sides of the vacuum transfer chamber160when viewed from the front side.

Each of the load ports141is configured as a placing table on which a carrier C accommodating wafers W to be processed is placed. Four load ports141are arranged side by side in the left-right direction when viewed from the front side. A front opening unified pod (FOUP) or the like can be used as the carrier C, for example.

The atmospheric transfer chamber140has an atmospheric pressure (normal pressure) atmosphere. For example, downflow of clean air is formed in the atmospheric transfer chamber140. A wafer transfer mechanism142for transferring the wafer W is disposed in the atmospheric transfer chamber140. The wafer transfer mechanism142in the atmospheric transfer chamber140is configured as a multi joint arm, for example. The wafer transfer mechanism142transfers the wafer W between the carriers C and the load-lock chambers130. An alignment chamber (not shown) for alignment of the wafer W is disposed on the left side of the atmospheric transfer chamber140, for example.

Two load-lock chambers130, for example, are arranged side by side between the vacuum transfer chamber160and the atmospheric transfer chamber140. Each of the load-lock chambers130has lift pins131for lifting and holding the wafer W loaded thereinto. For example, three lift pins131configured to be raised and lowered are disposed at equal intervals along a circumferential direction. Lift pins113and143to be described later have the same configuration.

The inner atmospheres of the load-lock chambers130can be switched between an atmospheric pressure atmosphere and a vacuum atmosphere. The load-lock chambers130and the atmospheric transfer chamber140are connected through gate valves133. Further, the load-lock chambers130and the vacuum transfer chamber160are connected through gate valves132.

The vacuum transfer chamber160corresponds to the substrate transfer chamber of the present disclosure. As shown inFIG.1, the vacuum transfer chamber160is configured as a rectangular housing elongated in a forward-backward direction in plan view. The vacuum transfer chamber160is evacuated to a vacuum atmosphere by a vacuum exhaust mechanism (not shown). Further, an inert gas supply device (not shown) for supplying an inert gas (e.g., nitrogen gas) may be connected to the vacuum transfer chamber160and constantly supply the inert gas into the vacuum transfer chamber160that has been decompressed. In the wafer processing system101shown in the example ofFIG.1, four wafer processing chambers110are connected to the right sidewall of the vacuum transfer chamber160through gate valves111, and other four wafer processing chambers110are connected to the left sidewall of the vacuum transfer chamber160through other gate valves111. The wafers W are loaded and unloaded between the vacuum transfer chamber160and the wafer processing chambers110through openings that are opened and closed by the gate valves111.

Each wafer processing chamber110is evacuated to a vacuum atmosphere by a vacuum exhaust mechanism (not shown). A placing table112is disposed in each wafer processing chamber110, and the wafer W is placed on the placing table112and subjected to predetermined processing. The processing to be performed on the wafer W may include etching, film formation, cleaning, ashing, or the like.

For example, in the case of performing processing while heating the wafer W, the placing table112is provided with a heater. When the processing to be performed on the wafer W uses a processing gas, the wafer processing chamber110is provided with a processing gas supply device including a shower head or the like. The illustration of the heater and the processing gas supply device is omitted. Further, the placing table112is provided with the lift pins113for transferring the wafer W to be loaded/unloaded. The wafer processing chamber110corresponds to the substrate processing chamber of the present embodiment.

In the vacuum transfer chamber160configured as described above, the wafer W is transferred using the magnetic levitation type transfer module (substrate transfer module)30. The transfer module30shown in the example ofFIGS.2and3includes a main body31having a rectangular shape in plan view. The main body31is provided with an arm portion32for holding the wafer W horizontally. The arm portion32is disposed to extend in the horizontal direction from a base end portion on the main body31side. A fork is disposed at a tip end of the arm portion32to surround a region where three lift pins131and113are disposed from both sides thereof. The fork corresponds to a substrate holder in the transfer module30.

The arm portion32has a length that allows the wafer W to be transferred onto the placing table112when the main body31is located in the vacuum transfer chamber160and the arm portion32enters the wafer processing chamber111by opening the gate valve111.

Module-side magnets33are disposed in the main body31of the transfer module30. A configuration example thereof will be described later with reference toFIG.3.

As schematically shown inFIG.3, a plurality of tiles (moving tiles)10are disposed on the floor of the vacuum transfer chamber160. The tiles10are disposed in the movement area of the transfer module30that extends from the position (position facing the load-lock chambers130) where the wafer W is transferred to and from the external atmospheric transfer chamber140to the front side of the wafer processing chamber110. When the transfer area is set such that the transfer module30enters the load-lock chamber130or the wafer processing chamber110and moves therein, the tiles10are also disposed on the floor of the load-lock chamber130or the wafer processing chamber110.

A plurality of moving surface-side coils11are arranged in each tile10. The moving surface-side coils11generates a magnetic field when a power is supplied from a power supply device (not shown). The moving surface-side coils11correspond to first magnets of the present disclosure.

On the other hand, the plurality of module-side magnets33that are permanent magnets, for example, are arranged in the transfer module30. A repulsive force (magnetic force) acts against the module-side magnets33by the magnetic field generated by the moving surface-side coils11. Accordingly, the transfer module30can be magnetically levitated with respect to the moving surface on the upper surface side of the tile10. The module-side magnets33disposed in the transfer module30correspond to second magnets of the present disclosure.

The tile10can change the magnetic field state by adjusting the position where the magnetic field is generated or the strength of the magnetic force using the moving surface-side coils11. By controlling the magnetic field, it is possible to move the transfer module30in a desired direction on the moving surface, adjust the levitation distance from the moving surface, and adjust the direction of the transfer module30. The magnetic field on the tile10side is controlled by selecting the moving surface-side coils11to which the power is supplied or by adjusting the magnitude of the power supplied to the moving surface-side coils11.

The module-side magnets33may include coils that receive a power from a battery disposed in the transfer module30and function as electromagnets. The module-side magnets33may include both a permanent magnet and a coil.

In the example shown inFIGS.1and3, the length in the short side direction of the rectangular vacuum transfer chamber160in plan view allows two transfer modules30arranged side by side and holding the wafers W to move without interference. The length in the short side direction of the vacuum transfer chamber160of this example is shorter than the length (the entire length of the transfer module30holding the wafer W) from the main body31to the tip end of the wafer W held by the transfer module30. In this example, the wafers W are transferred using the plurality of transfer modules30disposed in the vacuum transfer chamber160.

The vacuum transfer chamber160including the transfer module30and connected to the wafer processing chambers110, which has been described above, corresponds to the substrate transfer apparatus of the present disclosure.

The wafer processing system101includes a controller5. The controller5is a computer having a CPU and a storage device, and controls individual components of the wafer processing system101. The storage device stores a program including a group of steps (commands) for controlling the movement of the transfer module30, the operation of the wafer processing chambers110, or the like. The program is stored in a storage medium such as a hard disk, a compact disk, a magneto-optical disk, a memory card, a non-volatile memory, or the like, and installed in the computer from the storage medium.

<Transfer Operation of Wafer W>

Next, an example of an operation of transferring the wafer W in the wafer processing system101configured as described above will be described. First, when the carrier C accommodating wafers W to be processed is placed on the load port141, a wafer W is taken out from the carrier C by the wafer transfer mechanism142in the atmospheric transfer chamber140. Then, the wafer W is transferred to the alignment chamber (not shown) and aligned. When the wafer W is taken out from the alignment chamber by the wafer transfer mechanism142, the gate valve133is opened.

When the wafer transfer mechanism142enters the load-lock chamber130, the lift pins131are lifted to receive the wafer W. Then, the wafer transfer mechanism142retracts from the load-lock chamber130, and the gate valve133is closed. The inner atmosphere of the load-lock chamber130is switched from an atmospheric pressure atmosphere to a vacuum atmosphere.

When the load-lock chamber130has a vacuum atmosphere, the gate valve132is opened. At this time, in the vacuum transfer chamber160, the transfer module30stands by near the connection position with the load-lock chamber130while facing the load-lock chamber130. The transfer module30is raised by magnetic levitation using the magnetic field generated by the moving surface-side coils11disposed in the tile10.

Then, as shown inFIG.1, the arm portion32of the transfer module30enters the load-lock chamber130and is positioned below the wafer W supported by the lift pins131. The lift pins131are lowered to transfer the wafer W to the fork of the arm portion32.

Next, the arm portion32holding the wafer W retracts from the load-lock chamber130, and the transfer module30retracts to a lateral position of the wafer processing chamber110for processing the wafer W. At this time, the main body31of the transfer module30is moved to the rear end side of the vacuum transfer chamber160while passing through the area where the gate valve111is located. Accordingly, the tip end side of the arm portion32holding the wafer W is disposed at the lateral side of the gate valve111.

When the tip end side of the arm portion32reaches the lateral side of the gate valve111, the transfer module30retracts and also revolves such that the tip end side of the arm portion32faces the gate valve111. Then, the gate valve111is opened, and the transfer module30revolves to transfer the wafer W into the wafer processing chamber110and changes its movement direction to the forward direction.

As described above, the length in the short side direction of the vacuum transfer chamber160is shorter than the entire length of the transfer module30holding the wafer W. Even in this case, the wafer W can be transferred from the vacuum transfer chamber160into the wafer processing chamber110in by the operation of moving the transfer module30forward/backward while rotating the transfer module30.

Next, when the transfer module30faces the wafer processing chamber110, the transfer module30stops rotation and moves straight until the wafer W reaches a position above the placing table112. Then, the wafer W is transferred to the placing table112and the transfer module30retracts from the wafer processing chamber110. Then, the gate valve111is closed, and the processing of the wafer W is started.

In other words, the wafer W placed on the placing table112is heated, if necessary, to a preset temperature, and the processing gas is supplied into the wafer processing chamber110, if the processing gas supply device is provided. In this manner, desired processing is performed on the wafer W.

After the wafer W is processed for a preset period of time, the heating of the wafer W is stopped and the supply of the processing gas is stopped. The wafer W may be cooled by supplying a cooling gas into the wafer processing chamber110, if necessary. Then, the wafer W is transferred in the reverse order of the loading operation, and returned from the wafer processing chamber110to the load-lock chamber130.

After the inner atmosphere of the load-lock chamber130is switched to the atmospheric pressure atmosphere, the wafer W in the load-lock chamber130is taken out by the wafer transfer mechanism142in the atmospheric transfer chamber140and returned to a predetermined carrier C.

In the wafer processing system101configured as described above, particles may be generated by the contact between devices during the opening/closing operation of the gate valves132and111, for example. In addition, molecules of the processing gas supplied into the wafer processing chamber110may enter the vacuum transfer chamber160while being adsorbed to the wafer W and then released from the wafer W. The molecules of the processing gas may react with a small amount of moisture that exists in the vacuum transfer chamber160or is adsorbed on device surfaces, thereby forming particles or corrosive substances.

As will be described later, the vacuum transfer chamber160is constantly evacuated, so that the particles or molecules (chemical substances) are discharged to the outside of the vacuum transfer chamber160. Some of the particles or chemical substances may be adhered to the surface of the transfer module30before they are discharged from the vacuum transfer chamber160.

The particles or chemical substances adhered to and accumulated on the surface of the transfer module30may re-scatter and contaminate the wafer W. As described above, the moisture adsorbed on the device surfaces may react with the chemical substances, thereby forming particles or corrosive substances. Therefore, the wafer processing system101of this example includes a mechanism for releasing contaminants such as particles, chemical substances, and moisture adhered to the surface of the transfer module30. In the present disclosure, moisture is also included in the concept of “contaminants.”

In the wafer processing system101illustrated inFIGS.1and3, the mechanism for releasing contaminants is disposed in a cleaning area20set in the rear end portion of the vacuum transfer chamber160. The rear end portion of the vacuum transfer chamber160serves as a space where the main body31enters in the case of performing the operation of loading/unloading the wafer W into/from the wafer processing chamber110located on the rearmost side when viewed from the load ports141.

A heating device for heating the transfer module30to release contaminants from the surface of the transfer module30is disposed in the cleaning area20. Hereinafter, various configuration examples of the heating device will be described with reference toFIGS.5A to8.

First Configuration Example of Heating Device: Heating Light Source411

FIGS.5A and5Bare longitudinal cross-sectional views of the vacuum transfer chamber160taken along line A-A′ ofFIG.4(the same inFIGS.6to8).

As shown inFIG.5A, a plurality of heating light sources411as a first configuration example of the heating device of the present disclosure is disposed at a ceiling portion of the vacuum transfer chamber160in the cleaning area20. In this example, the heating light sources411are disposed on the upper surface side of the ceiling portion of the wafer processing system101to uniformly irradiate the cleaning area20with heating light for heating the surface of the transfer module30. Further, the area irradiated with the heating light can be adjusted by selecting the heating light source411to which a power is supplied from the power supply device (not shown).

The heating light sources411may include an infrared lamp such as a halogen lamp, or a light emitting diode (LED) lamp that emits infrared light. Each heating light source411may be provided with a lamp shade412to control the irradiation direction of the heating light.

The heating light sources411are arranged on the upper surface side of the ceiling portion of the vacuum transfer chamber160via a cover portion414and a holding portion413. A transmission window415made of quartz glass, for example, and transmitting the heating light is disposed between the area where the heating light sources411are arranged and the cleaning area20set in the vacuum transfer chamber160.

FIGS.5A and5Bshow an example in which a cooling device for cooling the transfer module30heated by the heating light sources411to a use temperature. In this example, the cooling device has a configuration in which a channel (temperature control fluid channel21) through which a coolant that is a temperature control fluid flows is formed in the tile10. In this case, the upper surface of the tile10serves as a contact surface to be in contact with the main body31. A coolant supply device432for supplying a coolant and stopping the supply of the coolant is connected to the temperature control fluid channel21.

A heating operation for releasing contaminants from the surface of the transfer module30in the wafer processing system101configured as described above will be described.

When it is required to heat the transfer module30, the main body31to be processed is moved to the cleaning area20and positioned below the heating light sources411. In the examples shown inFIGS.4,5A, and5B, one transfer module30is disposed. However, two transfer modules30may be arranged.

For example, the main body31may be heated after a preset period of time elapses from previous heating, or after a preset number of wafers W are transferred.

For convenience of description,FIG.4shows a state in which the transfer module30is disposed in the cleaning area20when the wafer W is transferred by another transfer module30in the vacuum transfer chamber160. In practice, it is preferable to heat the transfer module30while the wafer W is not being transferred in the vacuum transfer chamber160.

The period in which the wafer W is not transferred may include a period in which the wafer W is being processed in the wafer processing chamber110and there is a sufficient standby time, or a period in which all the wafers W are processed and there is no wafer W in the vacuum transfer chamber160or the wafer processing system101.

After the transfer module30(the main body31) is disposed in the cleaning area20, the heating light sources411in the region facing the main body31are turned on in a state where the transfer module30is levitated as shown inFIG.5A, and irradiate the heating light. Due to the irradiation of the heating light, the temperature of the surface of the main body31increases abruptly from room temperature. At this time, the surface of the main body31may be heated to a temperature in the range of 75° C. to 300° C., for example.

When the temperatures of the constituent members of the main body31or the particles adhered to the surfaces thereof increase abruptly, sudden thermal stress is applied to the main body31and, thus, a force that separates the particles from the surface of the main body31is applied. The force that separates particles from the surface of the main body31is also applied by the thermophoretic effect caused by a large temperature gradient between the surface of the main body31and the surrounding atmosphere. The particles adhered to the surface of the wafer W are released by such a force.

The chemical substances or moisture adhered to the surface of the wafer W is also decomposed or sublimated/vaporized by the heating of the main body31, and released from the surface of the wafer W.

The temperature of the bottom surface of the main body31, which is not irradiated with the heating light, also increases due to heat conduction from the upper surface. At this time, the heating is performed in a state where the main body31is levitated from the floor of the vacuum transfer chamber160, so that particles or chemical substances are released from the bottom surface of the main body31by the above-described mechanism.

The surface of the arm portion32connected to the main body31also increases due to heat conduction, and particles or chemical substances are released from the surface thereof.

The heating light sources411may be disposed to irradiate the heating light to the upper surface of the arm portion32. Alternatively, after the main body31is heated, the arm portion32may enter the cleaning area20by changing the direction of the transfer module30and the main body31may be directly heated.

Here, as shown inFIG.5A, one end of an exhaust channel161constituting an exhaust device for evacuating the vacuum transfer chamber160may be opened on the floor of the area where the cleaning area20is disposed. When the cleaning area20is set in the vacuum transfer chamber160, it is considered that the exhaust channel161constitutes the exhaust device for exhausting the atmosphere in which the transfer module30is heated.

Particles or chemical substances (contaminants) released from the surface of the transfer module30are discharged to the outside of the vacuum transfer chamber160through the exhaust channel161. Therefore, the exhaust channel161also functions as a contaminant removal device for removing contaminants released from the surface of the transfer module30.

As described above, when the inert gas is constantly supplied into the vacuum transfer chamber160, the supply flow rate of the inert gas may be increased during the heating of the transfer module30to facilitate evacuation. In this case, the pressure in the vacuum transfer chamber160may increase. Hence, the effect of pressure variation can be avoided by adjusting the processing schedule or the transfer schedule and heating the transfer module30during the period in which the wafer W is not transferred.

The transfer module30is heated for a preset time and the irradiation of the heating light from the heating light sources411is stopped when the surface of the main body31becomes clean. Then, the coolant is supplied from the coolant supply device432to the temperature control fluid channel21, and the transfer module30is lowered to bring the bottom surface of the transfer module30into contact with the tile10located in the region to which the coolant is supplied. When the bottom surface of the main body31is brought into contact with the surface (contact surface) of the cooled tile10, the entire transfer module30(the top and bottom surfaces of the main body31and the arm portion32) is cooled by heat conduction. Accordingly, even in the vacuum transfer chamber160that is being evacuated, the transfer module30can be quickly cooled to room temperature, for example, and the transfer of the wafer W can be resumed.

If the coolant is supplied to the temperature control fluid channel21even during the heating of the transfer module30, the scattered contaminants may be attracted and adhered to the surface of the cooled tile10by a thermophoretic force. Therefore, the coolant is not supplied during the heating of the transfer module30to avoid contamination of the tile10and suppress re-contamination of the transfer modules30in contact with the tile10during the cooling.

Second Configuration Example of Heating Device: Induction Coil421

FIG.6shows an example in which the induction coil421for induction heating is disposed, as a second configuration example of the heating device of the present disclosure, on the upper surface side of the ceiling portion of the vacuum transfer chamber160. The induction coil421is covered with the cover portion422. The induction coil421generates a magnetic field in a region below the induction coil421in the vacuum transfer chamber160by the power supplied from the power supply device (not shown).

The upper surface of the main body31that faces the induction coil421when the main body31is disposed in the cleaning area20is made of metal. When the power is supplied from the power supply device to the induction coil421and a magnetic field is formed in the vacuum transfer chamber160, the temperature of the upper surface of the main body31increases due to induction heating. The heating temperature of the main body31and the release of contaminants (particles or chemical substances) from the surface of the transfer module30(the upper and bottom surfaces of the main body31and the arm portion32) are the same as those described with reference toFIG.5A. Further, the cooling of the transfer module30by the contact with the tile10through which the coolant flows after the release of contaminants through the exhaust channel161or the release of the contaminants is the same as that described with reference toFIGS.5A and5B, so that the redundant description thereof will be omitted.

When it is difficult to levitate the transfer module30during the heating using the induction coil421, the transfer module30may be heated while being supported by a plurality of support pins, for example.

Third Configuration Example of Heating Device: Heat Exchange Mechanism

FIG.7Ashows an example in which a heat medium supply device431for supplying a heat medium that is a temperature control fluid to the temperature control fluid channel21formed in the tile10is provided as a heating device. In this case, while the heat medium is being supplied from the heat medium supply device431, the surface of the transfer module30is heated to a temperature in the range of 75° C. to 300° C. by heat conduction due to the contact between the main body31and the upper surface (contact surface) of the tile10(seeFIG.7A). The tile10in which the temperature control fluid channel21is formed or the heat medium supply device431corresponds to the heat exchange mechanism of this example.

Then, the transfer module30is heated for a preset time. When the surface of the main body31becomes clean, the heat medium is switched and the transfer module30is cooled by supplying the coolant from the coolant supply device432(seeFIG.7B).

Fourth Configuration Example of Heating Device: Resistance Heating Element313

FIG.8shows an example in which the resistance heating element313is disposed, as a heating device, in the transfer module30. Further, a power supply device for supplying a power to the resistance heating element313is disposed in the transfer module30. The resistance heating element313may be a secondary battery, for example. In this case, the main body31may be provided with a plug for connection to an external power source, and the secondary battery may be charged by inserting the plug into a socket. Alternatively, the secondary battery may be charged by wireless power supply.

In addition, the power may be directly supplied to the resistance heating element313by a plug-socket mechanism or wireless power supply without providing a secondary battery in the main body31. In this case, the plug or a power receiving part for wireless power supply corresponds to the power supply device314.

The resistance heating element313and the power supply device314correspond to the heating device of this example.

The contaminants can be released from the surface of the transfer module30by heating the transfer module30to a temperature in the range of 75° C. to 300° C. using the above-described resistance heating element313. The cooling of the transfer module30by the contact with the tile10through which the coolant flows is the same as that described in the example ofFIG.5B.

FIG.8shows an example of a technique for removing contaminants released from the transfer module30that is different from a technique for discharging contaminants through the exhaust channel161. In other words, a contaminant collecting member22having therein a coolant channel221is disposed at the ceiling portion of the vacuum transfer chamber160of this example, for example. The coolant supply device23is connected to the coolant channel221, so that the coolant that is a temperature control fluid can be supplied to the coolant supply device23.

Due to the coolant, the temperature of the surface of the contaminant collecting member22is adjusted to be lower than the temperature of the transfer module30heated by the resistance heating element313. The contaminants released from the surface of the transfer module30are transferred toward the contaminant collecting member22by a thermophoretic force generated by the temperature gradient between the surface of the transfer module30and the surface of the contaminant collecting member22, and adhered to the surface of the contaminant collecting member22. Accordingly, the contaminants released from the transfer module30can be removed from the vacuum transfer chamber160. The contaminant collecting member22corresponds to the contaminant removal device of this example.

Here, either one or both of the contaminant removal device using the exhaust channel161shown inFIGS.5A to7Band the contaminant removal device using the contaminant collecting member22shown inFIG.8may be selected, if necessary, and arranged. On the other hand, in the example shown inFIG.5A,5B, or6, the heating device (the heating light sources411or the induction coil421) is disposed at the ceiling portion of the vacuum transfer chamber160. In this case, the contaminant collecting member22may be disposed on the sidewall of the vacuum transfer chamber160, for example.

The wafer processing system101of the present disclosure provides the following effect. The heating device (the heating light sources411, the induction coil421, the coolant supply device432, the temperature control fluid channel21, or the resistance heating element313in the main body31) heats the surface of the transfer module30that utilizes magnetic levitation to transfer the wafer W. The particles adhered to the surface of the wafer W can be released by the thermal stress and the thermophoretic force generated by the heating. The chemical substance adhered to the surface of the wafer W can be decomposed or sublimated by the heating of the main body31and released from the surface of the wafer W. The transfer module30can be cleaned by releasing the contaminants adhered to the surface thereof.

Next, the modification of the location of the cleaning area20and the timing of heating a transfer module30awill be described with reference to an example of the wafer processing system101ashown inFIG.9. InFIGS.9to12to be described below, like reference numerals will be given to like parts in the wafer processing system101and transfer module30described with reference toFIGS.1to8.

In the wafer processing system101ashown inFIG.9, the cleaning areas20are located in the load-lock chambers130for switching a pressure because the wafer W is loaded/unloaded between the vacuum transfer chamber160and the atmospheric transfer chamber140. Hence, the wafer processing system101ais different from the wafer processing system101shown inFIGS.1and3in that the transfer module30is heated in the vacuum transfer chamber160.

In the wafer processing system101a, the floors of the wafer processing chambers110, the load-lock chambers130, and the atmospheric transfer chamber140are located at substantially the same height as the floor of the vacuum transfer chamber160. The tiles10having the moving surface-side coils11are also disposed on the floors thereof. Therefore, the transfer module30acan be moved by magnetic levitation in the wafer processing chambers110, the load-lock chambers130, and the atmospheric transfer chamber140. Hence, the wafer processing system101ais different from that of the wafer processing system101shown inFIGS.1and3in that the arm portion32enters the wafer processing chamber110or the load-lock chamber130to transfer the wafer W.

In the atmospheric transfer chamber140aof this example, the lift pins143are disposed on the floor thereof, and the wafer W is transferred to and from the wafer transfer mechanism142via the lift pins143. The atmospheric transfer chamber140acorresponds to “another substrate transfer chamber” of this example.

In the wafer processing system101of this example, the wafer W is transferred by the transfer module30athat does not have the arm portion32so that it can easily enter the load-lock chamber130or the wafer processing chamber110. As shown inFIG.10, in the transfer module30a, the wafer W is directly held on the upper surface of the main body31. In other words, the main body31of the transfer module30aserves as a stage34that is a substrate holder on which the wafer W is placed and held. For example, the stage34is formed in a flat rectangular plate shape.

The transfer module30aenters the wafer processing chamber110or the atmospheric transfer chamber140to transfer the wafer W to and from the lift pins113and143. The transfer module30ahas slits341for transferring the wafer W while avoiding interference with the lift pins113and143. The slits341are formed along the path through which the lift pins113and143pass when the stage34is moved to and from the position below the wafer W held by the lift pins113and143. The slits341are formed such that the direction of the wafer W at the time of moving the stage34to the position below the wafer W can be reversed by 180°. Accordingly, the transfer module30aand the wafer W can be arranged concentrically in a vertical direction without interference between the transfer module30aand the lift pins113and143.

In the atmospheric transfer chamber140configured as described above, the transfer module30aenters the atmospheric transfer chamber140avia the load-lock chamber130, receives an unprocessed wafer W from the lift pins143, and transfers a processed wafer W to the lift pins143. Although downflow of clean air is formed in the atmospheric transfer chamber140aas described above, a relatively large amount of particles exist in the atmospheric transfer chamber140acompared to the amount of particles in the vacuum transfer chamber160maintained in a vacuum atmosphere. In the atmospheric transfer chamber140a, moisture tends to be adsorbed on the transfer module30a. Further, the chemical substances adhered to the wafer W during the processing in the wafer processing chamber110may enter the atmospheric transfer chamber140aand react with moisture in the atmosphere or moisture adsorbed on the transfer module30ato form particles or corrosive chemical substances.

When the transfer module30ais moved between the atmospheric transfer chamber140aand the vacuum transfer chamber160having different cleanliness levels, contaminants or moisture may enter the vacuum transfer chamber160or the wafer processing chamber110by the movement of the transfer module30a. Therefore, the contaminants are released by heating the transfer module30ain the load-lock chamber130when the transfer module30ais moved from the atmospheric transfer chamber140ato the vacuum transfer chamber160. In this case, it is preferable that the transfer module30ais not transferring the wafer W. By heating the transfer module30a, the transfer module30ahaving a clean surface can enter the vacuum transfer chamber160or the wafer processing chamber110.

FIG.11shows a wafer processing system101bin which vacuum transfer chambers160and160ahaving different vacuum levels are connected via the load-lock chambers130, and the cleaning areas20are located in the load-lock chambers130. For example, the wafer processing110afor performing physical vapor deposition (PVD) film formation requires a higher vacuum level compared to the wafer processing chamber110for performing chemical vapor deposition (CVD) film formation. Further, for example, the PVD film formation may be performed continuously after the CVD film formation. Therefore, in the wafer processing system101bshown inFIG.11, the CVD film formation and the PVD film formation can be consecutively performed by connecting the first vacuum transfer chamber160connected to the wafer processing chamber110for CVD and the second vacuum transfer chamber160aconnected to the wafer processing chamber110afor PVD via the load-lock chambers130.

On the other hand, the second vacuum transfer chamber160aconnected to the wafer processing chamber110afor PVD film formation that requires a high vacuum level may require a higher cleanliness level compared to that in the first vacuum transfer chamber160. Thus, in the wafer processing system101bof this example, the cleaning areas20are located in the load-lock chambers130arranged between the first vacuum transfer chamber160and the second vacuum transfer chamber160a. With this configuration, when the transfer module30ais moved from the first vacuum transfer chamber160to the second vacuum transfer chamber160a, the transfer module30acan be heated in the load-lock chamber130and the contaminants can be released. In this case, it is preferable that the transfer module30ais not transferring the wafer W. The transfer module30ahaving a clean surface by heating the transfer module30acan enter the second vacuum transfer chamber160aor the wafer processing chamber110afor performing PVD film formation.

The first vacuum transfer chamber160and the second vacuum transfer chamber160ahave substantially the same configuration except that they have different wafer processing chambers110and110aconnected to openings. Further, the processing of the wafer Win the wafer processing chambers110and110aconnected to the first and second vacuum transfer chambers160and160ais not limited to a combination of PVD film formation and CVD film formation. For example, it is possible to perform an etching process in the wafer processing chamber110aconnected to the second vacuum transfer chamber160ahaving a high vacuum level, and then perform the CVD film formation in the wafer processing chamber110connected to the first vacuum transfer chamber160having a low vacuum level.

InFIG.11, the illustration of the load-lock chambers130arranged between the first vacuum transfer chamber160and the atmospheric transfer chamber140ais omitted. Similarly to the wafer processing system101ashown inFIG.9, the cleaning areas20may be located in the load-lock chambers130, and the transfer module30amay be heated.

Referring toFIG.11, the wafer processing chamber110may be connected to a transfer chamber maintained in an atmospheric atmosphere instead of the first vacuum transfer chamber160. In this case, the second vacuum transfer chamber160ais connected to the transfer chamber maintained in an atmospheric atmosphere through the load-lock chambers130where the cleaning areas20are located.

In the wafer processing systems101aand101baccording to the examples ofFIGS.9and11, the heating device disposed in the cleaning area20may be any one of the heating light sources411, the induction coil421, the coolant supply device432and the temperature control fluid channel21, and the resistance heating element313in the main body31described with reference toFIGS.5A to8. Further, the cooling device (the coolant supply device432, the temperature control fluid channel21, or the like) of the transfer module30amay be disposed on the floors of the load-lock chambers130. In addition, the exhaust device for exhausting the load-lock chambers130or the contaminant collecting member22may be provided as the contaminant removal device. When the contaminant removal device serves as the exhaust device, a vacuum exhaust channel for creating a vacuum atmosphere in the load-lock chamber130may be used.

Also in the wafer processing systems101aand101bof the examples ofFIGS.9and11, the wafer W may be transferred using the transfer module30having the arm portion32shown inFIG.2. In this case, the load-lock chambers130where the cleaning areas20are located have a size that allows the entire transfer module30having the arm portion32to be accommodated.

The heating of the transfer modules30and30ais not necessarily performed in the vacuum transfer chamber160shown inFIGS.1and4or the load-lock chambers130shown inFIGS.9and11. For example, a dedicated processing chamber for heating the transfer modules30and30amay be connected to the rear end of the vacuum transfer chamber160through an opening that can be opened and closed by a shutter, and the cleaning areas20may be set in the dedicated processing chamber.

<Correction of Movement Control>

As described above, in each of the wafer processing systems101,101a, and101b, the contaminants on the surface are released by heating the transfer modules30and30ausing the heating device (the heating light sources411, the induction coil421, the coolant supply device432and the temperature control fluid channel21, or the resistance heating element313in the main body31). On the other hand, it is known that the magnetic force of the module-side magnets33disposed in the transfer modules30and30adecreases due to thermal demagnetization when the module-side magnets33are heated.

For example,FIG.12shows an example in which the movement of the transfer modules30and30ais controlled using the function of a movement controller501of the controller5. The movement controller501moves the transfer modules30and30ato target position by selecting the moving surface-side coils11to which the power is supplied from the power supply device53or by adjusting the magnitude of the power supplied to the moving surface-side coils11.

When the magnetic force of the module-side magnets33in the transfer modules30and30adecreases, the repulsive force acting between the moving surface-side coils11and the module-side magnets33decreases. As a result, even if the moving surface-side coils11are selected in a preset order based on a recipe, and the movement control is performed by supplying a preset power to the moving surface-side coils11, the transfer modules30and30amay not reach the target positions.

Therefore, a wafer processing system101cshown inFIG.12includes a position detector52for specifying the actual positions of the transfer modules30and30ain the vacuum transfer chamber160. A sensor for detecting the positions of the transfer modules30and30ais disposed in the vacuum transfer chamber160, and the position detector52specifies the positions of the transfer modules30and30abased on the information obtained from the sensor.

The position detection sensor may include a plurality of Hall-effect sensors located at preset positions in the tile10, a laser displacement meter, and a camera for imaging the positions of the transfer modules30and30a.FIG.12shows an example in which the plurality of Hall-effect sensors51are disposed in the tile10.

The controller5has the function of a displacement amount detector503, and detects a positional displacement amount between the actual positions of the transfer modules30and30adetected by the position detector52and the target positions where the module-side magnets33reach when thermal demagnetization does not occur. Since it is considered that the positional displacement amount is caused by thermal demagnetization of the magnetic force of the module-side magnets33, the repulsive force between the moving surface-side coils11and the module-side magnets33controlled by the movement controller501is corrected to offset the positional displacement amount using the function of a corrector502of the controller5.

The corrector502may correct the repulsive force using linear correction, for example. For example, when it is detected that the levitation heights (the position in the Z direction shown inFIG.1) of the transfer modules30and30ahas decreased to 80% of the target heights due to thermal demagnetization, the corrector502corrects the control value outputted from the movement controller501such that the power supplied from the power supply device53to the moving surface-side coils11is increased by 1.25 times.

When the influence of the heat source increases and, thus, it is difficult to reduce the positional displacement amount even after the correction, an error may be issued by the wafer processing systems101,101ato101c. When the error is issued, the original magnetic force may be restored by taking out the transfer modules30and30aand magnetizing the module-side magnets33at the outside.

The embodiments of the present disclosure are illustrative in all respects and are not restrictive. The above-described embodiments may be omitted, replaced, or changed in various forms without departing from the scope of the appended claims and the gist thereof.