JP7638134B2 - SUBSTRATE PROCESSING METHOD, STORAGE MEDIUM, AND SUBSTRATE PROCESSING APPARATUS - Google Patents

Description

The present disclosure relates to a substrate processing method, a storage medium, and a substrate processing apparatus.

Patent document 1 discloses a coating film removal device that uses a removal liquid to remove the peripheral edge of a coating film formed by supplying a coating liquid to the surface of a circular substrate.

JP 2018-121045 A

The present disclosure provides a substrate processing method, a storage medium, and a substrate processing apparatus that can reduce the rise in film thickness at the end of the processing liquid film after the peripheral region has been removed.

A substrate processing method according to one aspect of the present disclosure includes performing an intermittent removal process to remove a peripheral region of a film formed on a surface of a substrate by a processing liquid. The intermittent removal process includes alternately performing a first process in which a removal liquid for removing the film is supplied from a nozzle to the peripheral region while rotating the substrate, and a second process in which, after performing the first process, a state in which removal liquid is not supplied from the nozzle to the peripheral region while rotating the substrate is maintained.

The present disclosure provides a substrate processing method, a storage medium, and a substrate processing apparatus that can reduce the rise in film thickness at the end of the processing liquid film after the peripheral region has been removed.

FIG. 1 is a schematic diagram showing an example of a substrate processing system. FIG. 2 is a schematic diagram showing an example of a coating and developing apparatus. FIG. 3 is a schematic diagram illustrating an example of the liquid processing unit. 4A and 4B are schematic diagrams showing an example of the arrangement of nozzles during ejection. FIG. 5 is a block diagram illustrating an example of a hardware configuration of the control device. FIG. 6 is a flowchart showing an example of a method for removing the peripheral region. 7A and 7B are schematic diagrams showing an example of how the peripheral region is removed. 8A and 8B are schematic diagrams showing an example of how the peripheral region is removed. FIG. 9 is a flowchart showing an example of a method for removing the peripheral region. 10A and 10B are schematic diagrams showing an example of how the peripheral region is removed. 11A and 11B are graphs showing an example of the evaluation results of the film thickness in the peripheral region. 12A and 12B are graphs showing an example of the measurement results of the film thickness distribution according to the comparative example and the example, respectively.

First, we will provide an overview of the embodiment.

A substrate processing method according to one aspect of the present disclosure includes performing an intermittent removal process to remove a peripheral region of a film formed on a surface of a substrate by a processing liquid. The intermittent removal process includes alternately performing a first process in which a removal liquid for removing the film is supplied from a nozzle to the peripheral region while rotating the substrate, and a second process in which, after performing the first process, a state in which removal liquid is not supplied from the nozzle to the peripheral region while rotating the substrate is maintained.

When the peripheral region of the film of the processing liquid is removed by the removing liquid, a mixed layer is formed in the peripheral region of the substrate by mixing a part of the film of the processing liquid with the removing liquid. Therefore, the film thickness at the end of the film after the peripheral region is removed becomes thick. In contrast, in the above-mentioned substrate processing method, a state in which the removing liquid is supplied to the peripheral region and a state in which the removing liquid is not supplied to the peripheral region are alternately performed, so that the time for supplying the removing liquid to the peripheral region is shortened and the formation of a mixed layer is suppressed. In addition, by rotating the substrate in a state in which the removing liquid is not supplied, the mixed layer can be discharged outside the substrate. Therefore, it is possible to reduce the rise in film thickness at the end of the film of the processing liquid after the peripheral region is removed.

The above substrate processing method may start at least one first process performed in the intermittent removal process by moving the nozzle so that the area where the removal liquid reaches from the nozzle in a state where the removal liquid is being ejected moves from a position outside the periphery of the substrate to the peripheral area. In this case, the number of times that the nozzle that has stopped ejecting the removal liquid is transitioned to a state where it ejects the removal liquid in order to start the first process can be reduced. As a result, it is possible to reduce the frequency of occurrence of malfunctions that may occur when the nozzle starts ejecting the removal liquid.

The above substrate processing method may start at least one first process executed in the intermittent removal process by switching an opening/closing valve that opens and closes a flow path that sends removal liquid to the nozzle from a closed state to an open state with the nozzle positioned at a position where removal liquid can be supplied to the peripheral region. In this case, the period during which removal liquid is continuously discharged without being supplied to the processing liquid film before the first process is started can be reduced. As a result, it is possible to reduce the amount of removal liquid discharged in the intermittent removal process including the second process in which removal liquid is not supplied.

The above substrate processing method may start at least one second process performed in the intermittent removal process by moving the nozzle so that the area where the removal liquid reaches from the nozzle while it is ejecting the removal liquid moves from the peripheral area to a position outside the peripheral edge of the substrate. In this case, the number of times that the nozzle ejecting the removal liquid is transitioned to a state where ejection is stopped in order to start the second process can be reduced. As a result, it is possible to reduce the frequency of occurrence of malfunctions that may occur when the nozzle stops ejecting the removal liquid.

The above substrate processing method may start at least one second process performed in the intermittent removal process by switching an opening/closing valve that opens and closes a flow path that sends the removal liquid to the nozzle from an open state to a closed state with the nozzle positioned at a position where the removal liquid can be supplied to the peripheral region. In this case, after the second process is started, the period during which the removal liquid is continuously discharged without being supplied to the processing liquid film can be reduced. As a result, it is possible to reduce the amount of removal liquid discharged in the intermittent removal process including the second process in which the removal liquid is not supplied.

The substrate processing method may further include continuing to supply the removal liquid to the peripheral region for a predetermined period of time while rotating the substrate after performing the intermittent removal process. In this case, the time required to remove a target amount of the peripheral region of the processing liquid film is shortened. As a result, it is possible to achieve both reduction in the swelling of the film thickness at the edge and processing efficiency.

The second process may include rotating the substrate so as to expel the portion of the film softened by the removal liquid outside the substrate. A portion of the film softened by the removal liquid may remain in the peripheral region of the substrate, causing an increase in film thickness. In the above method, a portion of the film softened by the removal liquid is expelled outside the substrate, making it possible to reduce the increase in film thickness at the edge of the film after the peripheral region is removed.

The second process may include rotating the substrate so as to discharge the liquid, which is a mixture of the components of the film dissolved by the removal liquid and the removal liquid, outside the substrate. If the mixed liquid remains in the peripheral region of the substrate, a rise in the film thickness may occur. In the above method, the mixed liquid of the components dissolved by the removal liquid and the removal liquid is discharged outside the substrate, making it possible to reduce the rise in the film thickness at the edge after the peripheral region is removed.

A storage medium according to one aspect of the present disclosure is a computer-readable storage medium that stores a program for causing an apparatus to execute any one of the substrate processing methods described above.

A substrate processing apparatus according to one aspect of the present disclosure includes a liquid processing unit having a rotating holder that holds and rotates a substrate, a processing liquid supplying unit that supplies a predetermined processing liquid to the substrate held by the rotating holder, and a removing liquid supplying unit that includes a nozzle and supplies removing liquid from the nozzle to the substrate held by the rotating holder, and a control unit that controls the liquid processing unit. The control unit controls the liquid processing unit to form a film of the processing liquid on the surface of the substrate, and controls the liquid processing unit to perform an intermittent removal process that removes the peripheral region of the film. The intermittent removal process includes alternately performing a first process in which the removing liquid supplying unit supplies removing liquid from the nozzle to the peripheral region while rotating the substrate by the rotating holder, and a second process in which the removing liquid supplying unit maintains a state in which removing liquid is not supplied from the nozzle to the peripheral region while rotating the substrate by the rotating holder after the first process is performed. In this substrate processing apparatus, as in the above-mentioned substrate processing method, it is possible to reduce the rise in film thickness at the end of the film of the processing liquid after the peripheral region is removed.

The removal liquid supplying section may further include a drive section that moves the nozzle along the surface of the substrate, and an opening/closing valve that opens and closes a flow path that supplies the removal liquid to the nozzle. The control unit may cause the liquid processing unit to start at least one first process performed in the intermittent removal process by moving the nozzle with the drive section so that the area where the removal liquid reaches from the nozzle in a state where the removal liquid is being ejected moves from a position outside the periphery of the substrate to the peripheral area. In this case, as with the substrate processing method described above, it is possible to reduce the frequency of occurrence of malfunctions that may occur when the nozzle starts ejecting the removal liquid.

The removal liquid supplying section may further include a drive section that moves the nozzle along the surface of the substrate, and an opening/closing valve that opens and closes a flow path that supplies the removal liquid to the nozzle. The control unit may cause the liquid processing unit to start at least one first process executed in the intermittent removal process by switching the opening/closing valve from a closed state to an open state with the nozzle positioned at a position that allows the removal liquid to be supplied to the peripheral region. In this case, as with the substrate processing method described above, it is possible to reduce the amount of removal liquid discharged in the intermittent removal process that includes a second process in which the removal liquid is not supplied.

The control unit may cause the liquid processing unit to start at least one second process performed in the intermittent removal process by moving the nozzle with the drive unit so that the area where the removal liquid reaches from the nozzle while it is being ejected moves from the peripheral area to a position outside the peripheral edge of the substrate. In this case, as with the substrate processing method described above, it is possible to reduce the frequency of occurrence of malfunctions that may occur when ejection of the removal liquid from the nozzle is stopped.

The control unit may cause the liquid processing unit to start at least one second process performed in the intermittent removal process by switching the on-off valve from an open state to a closed state while the nozzle is positioned so that the removal liquid can be supplied to the peripheral region. In this case, as in the substrate processing method described above, it is possible to reduce the amount of removal liquid discharged in the intermittent removal process including the second process in which the removal liquid is not supplied.

Below, an embodiment will be described with reference to the drawings. In the description, identical elements or elements having the same functions are given the same reference numerals, and duplicated descriptions will be omitted. Some drawings show an orthogonal coordinate system defined by the X-axis, Y-axis, and Z-axis. In the following embodiment, the Z-axis corresponds to the vertical direction, and the X-axis and Y-axis correspond to the horizontal direction.

[Substrate Processing System]
The substrate processing system 1 (substrate processing apparatus) shown in FIG. 1 is a system that forms a photosensitive film on a workpiece W, exposes the photosensitive film, and develops the photosensitive film. The workpiece W to be processed is, for example, a substrate, or a substrate on which a film, circuit, or the like has been formed by performing a predetermined process. One example of the substrate is a silicon wafer. The workpiece W (substrate) may be circular. The workpiece W may be a glass substrate, a mask substrate, or an FPD (Flat Panel Display), etc. The photosensitive film is, for example, a resist film.

As shown in Figures 1 and 2, the substrate processing system 1 includes a coating and developing apparatus 2, an exposure apparatus 3, and a control device 100 (control unit). The exposure apparatus 3 is an apparatus that exposes a resist film (photosensitive coating) formed on a workpiece W (substrate). Specifically, the exposure apparatus 3 irradiates an energy beam onto an exposure target portion of the resist film by a method such as immersion exposure.

(Coating and developing equipment)
The coating and developing apparatus 2 applies a resist (chemical solution) to the surface of the workpiece W to form a resist film before the exposure process by the exposure device 3, and develops the resist film after the exposure process. The coating and developing apparatus 2 includes a carrier block 4, a processing block 5, and an interface block 6.

The carrier block 4 introduces the workpiece W into the coating and developing apparatus 2 and removes the workpiece W from the coating and developing apparatus 2. For example, the carrier block 4 can support multiple carriers C for the workpiece W and has a built-in transport device A1 including a transfer arm. The carrier C accommodates, for example, multiple circular workpieces W. The transport device A1 removes the workpiece W from the carrier C and passes it to the processing block 5, and receives the workpiece W from the processing block 5 and returns it to the carrier C. The processing block 5 has processing modules 11, 12, 13, and 14.

The processing module 11 incorporates a liquid processing unit U1, a heat processing unit U2, and a transport device A3 that transports the workpiece W to these units. The processing module 11 forms an underlayer film on the surface of the workpiece W using the liquid processing unit U1 and the heat processing unit U2. The liquid processing unit U1 applies a processing liquid for forming the underlayer film onto the workpiece W. The heat processing unit U2 performs various heat treatments associated with the formation of the underlayer film.

The processing module 12 incorporates a liquid processing unit U1, a heat processing unit U2, and a transport device A3 that transports the workpiece W to these units. The processing module 12 forms a resist film on the underlayer film using the liquid processing unit U1 and the heat processing unit U2. The liquid processing unit U1 applies a processing liquid for forming a resist film onto the underlayer film. The processing liquid applied by the liquid processing unit U1 may be a resist liquid with a medium viscosity or higher (for example, a viscosity of 50 cP or higher). The liquid processing unit U1 removes the peripheral area of the film formed by the processing liquid, which is applied (supplied) with the processing liquid for forming the resist film, using a chemical liquid different from the above processing liquid. The heat processing unit U2 performs various heat treatments associated with the formation of the resist film.

The processing module 13 incorporates a liquid processing unit U1, a heat processing unit U2, and a transport device A3 that transports the workpiece W to these units. The processing module 13 forms an upper layer film on the resist film using the liquid processing unit U1 and the heat processing unit U2. The liquid processing unit U1 applies a processing liquid for forming the upper layer film onto the resist film. The heat processing unit U2 performs various heat treatments associated with the formation of the upper layer film.

The processing module 14 incorporates a liquid processing unit U1, a heat processing unit U2, and a transport device A3 that transports the workpiece W to these units. The processing module 14 uses the liquid processing unit U1 and the heat processing unit U2 to perform development processing of the resist film that has been subjected to exposure processing and heat processing associated with the development processing. The liquid processing unit U1 supplies a developer onto the surface of the exposed workpiece W, and then rinses it away with a rinsing liquid to form a resist pattern (development processing of the resist film). The heat processing unit U2 performs various heat processing associated with the development processing. Specific examples of heat processing include a heating process before development (PEB: Post Exposure Bake) and a heating process after development (PB: Post Bake), etc.

A shelf unit U10 is provided on the carrier block 4 side within the processing block 5. The shelf unit U10 is divided into multiple cells arranged in the vertical direction. A transport device A7 including a lifting arm is provided near the shelf unit U10. The transport device A7 raises and lowers the workpiece W between the cells of the shelf unit U10.

A shelf unit U11 is provided on the interface block 6 side of the processing block 5. The shelf unit U11 is divided into multiple cells arranged vertically.

The interface block 6 transfers the workpiece W to and from the exposure device 3. For example, the interface block 6 has a built-in transport device A8 including a transfer arm, and is connected to the exposure device 3. The transport device A8 transfers the workpiece W placed on the shelf unit U11 to the exposure device 3. The transport device A8 receives the workpiece W from the exposure device 3 and returns it to the shelf unit U11.

The control device 100 is configured to control the coating and developing apparatus 2 partially and entirely. The control device 100 controls the coating and developing apparatus 2 to perform a coating and developing process, for example, in the following procedure. First, the control device 100 controls the transport device A1 to transport the workpiece W in the carrier C to the shelf unit U10, and then controls the transport device A7 to place the workpiece W in the cell for the processing module 11.

The control device 100 then controls the transport device A3 to transport the workpiece W from the shelf unit U10 to the liquid treatment unit U1 and heat treatment unit U2 in the processing module 11. The control device 100 also controls the liquid treatment unit U1 and heat treatment unit U2 to form an underlayer film on the surface of the workpiece W. The control device 100 then controls the transport device A3 to return the workpiece W with the underlayer film formed thereon to the shelf unit U10, and controls the transport device A7 to place the workpiece W in a cell for the processing module 12.

Next, the control device 100 controls the transport device A3 to transport the workpiece W on the shelf unit U10 to the liquid processing unit U1 and heat processing unit U2 in the processing module 12. The control device 100 also controls the liquid processing unit U1 and heat processing unit U2 to form a resist film on the underlying film of the workpiece W.

In detail, the control device 100 controls the liquid processing unit U1 to form a film of the processing liquid for forming a resist film on the surface of the workpiece W, and then to remove the peripheral area of the film of the processing liquid. Then, the control device 100 controls the heat processing unit U2 to heat the workpiece W having the film of the processing liquid with the peripheral area removed, thereby forming a resist film. After the resist film is formed, the control device 100 controls the transport device A3 to return the workpiece W to the shelf unit U10, and controls the transport device A7 to place the workpiece W in a cell for the processing module 13.

The control device 100 then controls the transport device A3 to transport the workpiece W from the shelf unit U10 to each unit in the processing module 13. The control device 100 also controls the liquid processing unit U1 and the heat processing unit U2 to form an upper layer film on the resist film of the workpiece W. The control device 100 then controls the transport device A3 to transport the workpiece W to the shelf unit U11.

Next, the control device 100 controls the transport device A8 to send the workpiece W from the shelf unit U11 to the exposure device 3. The control device 100 then controls the transport device A8 to receive the workpiece W that has been subjected to the exposure process from the exposure device 3 and place it in a cell for the processing module 14 in the shelf unit U11.

The control device 100 then controls the transport device A3 to transport the workpiece W from the shelf unit U11 to each unit in the processing module 14, and controls the liquid processing unit U1 and the heat processing unit U2 to perform development processing of the resist film on the workpiece W. As the resist film is developed, a resist pattern is formed on the surface Wa of the workpiece W.

Then, the control device 100 controls the transport device A3 to return the workpiece W to the shelf unit U10, and controls the transport device A7 and the transport device A1 to return the workpiece W into the carrier C. This completes the coating and developing process for one workpiece W. The control device 100 causes the coating and developing device 2 to perform the coating and developing process for each of the subsequent multiple workpieces W in the same manner as described above.

The specific configuration of the substrate processing apparatus is not limited to the configuration of the substrate processing system 1 exemplified above. The substrate processing apparatus may be any type that includes a device that removes the peripheral area of the film using a processing liquid for forming a resist film, and a control device that can control this device.

<Liquid processing unit>
Next, an example of the liquid processing unit U1 in the processing module 12 will be described in detail with reference to Figures 3 and 4. In the following, unless otherwise specified, "processing liquid" means a processing liquid (resist liquid) for forming a resist film. "Processing liquid film" means a film of the processing liquid formed on the surface Wa of the workpiece W. In addition, the surface of the workpiece W is referred to as "surface Wa", and the periphery of the workpiece W is referred to as "periphery Wb". The peripheral area on the surface Wa of the workpiece W is the periphery Wb on the surface Wa and the area nearby it.

The liquid processing unit U1 forms a film of processing liquid on the surface Wa of the workpiece W. For example, the liquid processing unit U1 supplies processing liquid to the surface Wa while rotating the workpiece W, and then continues rotating the workpiece W for a predetermined time with the supply of processing liquid stopped. This forms a film of processing liquid on the surface Wa of the workpiece W. The liquid processing unit U1 performs a process of removing the peripheral area of the processing liquid film using a chemical liquid for removing the processing liquid film (hereinafter referred to as the "removal liquid").

The peripheral region of the treatment liquid film is the peripheral region of the film and the region in its vicinity. Note that before the peripheral region of the treatment liquid film is removed, the peripheral region of the surface Wa of the workpiece W corresponds to the peripheral region of the treatment liquid film formed on the surface Wa. The removal liquid is a solvent that can remove (dissolve) the film formed by the treatment liquid. Specific examples of the removal liquid include organic solvents such as thinner. As shown in FIG. 3, the liquid treatment unit U1 has a rotating holder 20, a treatment liquid supply unit 30, and a removal liquid supply unit 40.

The rotating holding unit 20 holds and rotates the workpiece W. The rotating holding unit 20 has, for example, a holding unit 21 and a rotation drive unit 22. The holding unit 21 supports the center of the workpiece W that is horizontally placed with its surface Wa facing upward, and holds the workpiece W by suction (for example, vacuum suction). The rotation drive unit 22 includes a power source such as an electric motor, and rotates the holding unit 21 around the vertical axis Ax. This causes the workpiece W to rotate. The rotating holding unit 20 may hold and rotate the workpiece W so that the center CP of the workpiece W (see FIG. 4(a)) approximately coincides with the axis Ax.

The processing liquid supply unit 30 supplies processing liquid to the surface Wa of the workpiece W held by the rotating holder 20. The processing liquid supply unit 30 has, for example, a nozzle 31, a liquid source 32, a liquid delivery unit 33, and a drive unit 34. The nozzle 31 ejects processing liquid toward the surface Wa of the workpiece W. The liquid source 32 contains processing liquid and pressure-feeds the processing liquid to the nozzle 31. The liquid delivery unit 33 guides the processing liquid from the liquid source 32 to the nozzle 31. The liquid delivery unit 33 has, for example, a liquid delivery pipe L1 and an opening/closing valve V1. The liquid delivery pipe L1 connects the liquid source 32 and the nozzle 31, and forms a flow path that delivers processing liquid to the nozzle 31.

The opening/closing valve V1 opens and closes the flow path in the liquid supply pipe L1 based on an operational command from the control device 100. When the opening/closing valve V1 is open, the processing liquid is discharged from the nozzle 31, and when the opening/closing valve V1 is closed, the discharge of the processing liquid from the nozzle 31 is stopped. The opening/closing valve V1 is, for example, an air operation valve. The drive unit 34 includes a power source such as an electric motor, and moves the nozzle 31 along the surface Wa of the workpiece W based on an operational command from the control device 100. The drive unit 34 moves the nozzle 31, for example, between the axis Ax (above the center CP of the workpiece W) and an area outside the workpiece W.

The removal liquid supply unit 40 supplies the removal liquid to the workpiece W held by the rotating holder 20. The removal liquid supply unit 40 is configured to be able to supply the removal liquid to the peripheral region of the film of the processing liquid formed on the surface Wa of the workpiece W. The removal liquid supply unit 40 has, for example, a nozzle 41, a liquid source 42, a liquid delivery unit 43, and a drive unit 44. The nozzle 41 ejects the removal liquid toward the peripheral region of the surface Wa of the workpiece W rotated by the rotating holder 20. The nozzle 41 is disposed above the surface Wa of the workpiece W. The nozzle 41 may eject the removal liquid in a direction perpendicular to the surface Wa of the workpiece W (vertically downward), or in a direction inclined from the perpendicular direction.

The liquid source 42 contains the removal liquid and pressure-feeds the removal liquid to the nozzle 41. The liquid delivery unit 43 guides the removal liquid from the liquid source 42 to the nozzle 41. The liquid delivery unit 43 has, for example, a liquid delivery tube L2 and an opening/closing valve V2. The liquid delivery tube L2 connects the liquid source 42 and the nozzle 41, and forms a flow path that sends the removal liquid to the nozzle 41. The opening/closing valve V2 opens and closes the flow path in the liquid delivery tube L2 based on an operation instruction from the control device 100. When the opening/closing valve V2 is in an open state, the removal liquid is discharged from the nozzle 41, and when the opening/closing valve V2 is in a closed state, the discharge of the removal liquid from the nozzle 41 is stopped. The opening/closing valve V2 is, for example, an air operation valve.

The drive unit 44 includes a power source such as an electric motor, and moves the nozzle 41 along the surface Wa of the workpiece W based on operation instructions from the control device 100. As the nozzle 41 moves along the surface Wa, the area reached by the removal liquid discharged from the nozzle 41 changes. Here, the arrival area AR of the removal liquid discharged from the nozzle 41 is defined as follows (see FIG. 4(a)). The arrival area AR is an area including the intersection of a virtual line extending in the direction in which the removal liquid is discharged from the nozzle 41 (e.g., a direction perpendicular to the discharge port of the nozzle 41) and a virtual plane including the surface Wa of the workpiece W, and the vicinity thereof. The outer edge (shape) and size of the arrival area AR change depending on the shape and size of the discharge port of the nozzle 41.

When the reach area AR overlaps with the surface Wa of the workpiece W (located inside the periphery Wb), the removal liquid ejected from the nozzle 41 reaches the surface Wa and is supplied onto the surface Wa. When the reach area AR does not overlap with the surface Wa of the workpiece W (located outside the periphery Wb), the removal liquid ejected from the nozzle 41 is not supplied to the surface Wa of the workpiece W. In this case, for example, the removal liquid ejected from the nozzle 41 is received in a cup (not shown) that surrounds the rotating holder 20.

The drive unit 44 moves the nozzle 41 so that the reach area AR changes along a virtual line rL corresponding to one radial direction of the workpiece W. The drive unit 44 moves the nozzle 41 so that the reach area AR changes at least between the peripheral area of the treatment liquid film (the peripheral area of the surface Wa) and a position outside the peripheral edge Wb of the workpiece W. In the example shown in FIG. 4(a), the virtual line rL is set to extend along the Y-axis direction. In this case, the drive unit 44 moves the nozzle 41 so that the movement direction of the nozzle 41 is along the Y-axis direction.

In a top view (when the surface Wa of the workpiece W is viewed from the axis Ax), the ejection direction VD of the removal liquid from the nozzle 41 may be inclined with respect to a virtual reference line SL perpendicular to the virtual line rL. Unlike the example in FIG. 4(a), the ejection direction VD may be along the reference line SL. The reference line SL perpendicular to the virtual line rL is parallel to the tangent at the intersection of the virtual line rL and the periphery Wb of the surface Wa. The angle α between the ejection direction VD of the removal liquid from the nozzle 41 and the reference line SL may be -30° to +30°, -15° to +15°, or -10° to +10°.

The angle α has a negative value when the ejection direction VD of the removal liquid from the nozzle 41 is inclined toward the center CP of the surface Wa with respect to the reference line SL. In this case, the component of the ejection direction VD along the imaginary line rL faces the center CP of the surface Wa. The angle α has a positive value when the ejection direction VD of the removal liquid from the nozzle 41 is inclined toward the center CP of the surface Wa with respect to the reference line SL. In this case, the component of the ejection direction VD along the imaginary line rL faces in a direction away from the center CP of the surface Wa.

When the arrival area AR overlaps with the surface Wa, the direction of the component of the discharge direction VD of the removal liquid from the nozzle 41 along the reference line SL and the direction of rotation RD of the workpiece W by the rotating and holding unit 20 may be opposite to each other in the arrival area AR. In FIG. 4(a), the rotation direction RD is shown clockwise, and is downward on the paper in the arrival area AR, and the component of the discharge direction VD along the reference line SL is upward on the paper. Unlike the example in FIG. 4(a), when the arrival area AR is included within the surface Wa, the direction of the component of the discharge direction VD along the reference line SL and the direction of rotation RD of the workpiece W by the rotating and holding unit 20 may be the same in the arrival area AR.

As shown in FIG. 4(b), in a side view (when the peripheral edge Wb is viewed from the radial direction of the workpiece W), the angle β between the ejection direction VD of the removal liquid from the nozzle 41 and the surface Wa of the workpiece W may be smaller than 90°. The angle β may be 5° to 40°, 8° to 35°, or 10° to 30°.

(Control device)
After the workpiece W with the underlayer film formed thereon is carried into the liquid treatment unit U1, the control device 100 controls the liquid treatment unit U1 to form a film of the treatment liquid on the surface Wa of the workpiece W. In detail, the control device 100 supplies the treatment liquid to the surface Wa by the treatment liquid supply unit 30 while rotating the workpiece W by the spin holding unit 20. Then, the control device 100 rotates the workpiece W by the spin holding unit 20 for a predetermined drying time while stopping the supply of the treatment liquid to the treatment liquid supply unit 30. As a result, part of the solvent contained in the treatment liquid on the surface Wa volatilizes, and a film of the treatment liquid is formed on the surface Wa of the workpiece W.

The control device 100 controls the liquid processing unit U1 to perform a process for removing the peripheral region of the processing liquid film (hereinafter referred to as the "removal process") after the processing liquid film is formed on the surface Wa. The removal process includes at least an intermittent removal process. The intermittent removal process includes alternately performing the following first and second processes. The first process is a process in which the removal liquid supply unit 40 supplies the removal liquid from the nozzle 41 to the peripheral region of the processing liquid film while rotating the workpiece W by the rotating holder 20. The second process is a process in which, after performing the first process, the removal liquid supply unit 40 maintains a state in which the removal liquid is not supplied from the nozzle 41 to the peripheral region of the processing liquid film while rotating the workpiece W by the rotating holder 20. In the second process, the removal liquid is not supplied from any nozzle to the peripheral region of the processing liquid film.

In the present disclosure, alternately executing the first process and the second process means at least executing the first process and the second process in sequence, and then executing the first process again. In the intermittent removal process, the control device 100 alternately executes the first process multiple times and at least one second process, one at a time. In addition to the intermittent removal process, the removal process may also include a process of continuously supplying the removal liquid to the peripheral region of the treatment liquid film (hereinafter referred to as a "continuous removal process"). Specific examples of the intermittent removal process and the continuous removal process will be described later.

The control device 100 is composed of one or more control computers. The control device 100 has, for example, a circuit 120 shown in FIG. 5. The circuit 120 has one or more processors 122, a memory 124, a storage 126, an input/output port 128, and a timer 132. The storage 126 has a storage medium readable by a computer, such as a hard disk. The storage medium stores a program for causing the control device 100 to execute a substrate processing method described below. The storage medium may be a removable medium such as a non-volatile semiconductor memory, a magnetic disk, or an optical disk. The memory 124 temporarily stores the program loaded from the storage medium of the storage 126 and the results of calculations by the processor 122.

The processor 122 executes the above program in cooperation with the memory 124. The input/output port 128 inputs and outputs electrical signals between the spin holder 20, the processing liquid supply unit 30, and the removal liquid supply unit 40, etc., in accordance with instructions from the processor 122. The timer 132 measures the elapsed time, for example, by counting a reference pulse at a constant period. The hardware configuration of the control device 100 may be configured with a dedicated logic circuit or an ASIC (Application Specific Integrated Circuit) that integrates the dedicated logic circuit.

[Substrate Processing Method]
6 to 8, a method for removing a film of a processing liquid (more specifically, a removal process for removing a peripheral area of a film of a processing liquid) performed on one workpiece W in the liquid processing unit U1 of the processing module 12 will be described as an example of a substrate processing method. Fig. 6 is a flow chart showing an example of a series of processes performed by the control device 100 in the removal process. In this removal process, the control device 100 performs step S11 while the workpiece W having a film of a processing liquid formed on its surface Wa is being rotated by the spin holder 20 at a predetermined first rotation speed.

In step S11, for example, the control device 100 moves the nozzle 41, which is arranged so that the arrival area AR of the removal liquid is located outside the peripheral edge Wb of the workpiece W, by the drive unit 44 so that the arrival area AR overlaps the peripheral area. Hereinafter, in step S11, the position of the nozzle 41 arranged so that the arrival area AR is located in the peripheral area is referred to as the "first discharge position". FIG. 7(a) illustrates an example of the operation of the nozzle 41, which is not discharging the removal liquid Lr, moving to the first discharge position. The nozzle 41 arranged in the first discharge position can discharge the removal liquid toward the peripheral area PA of the film R of the processing liquid (the peripheral area of the surface Wa of the workpiece W held by the rotating holder 20). For the purpose of explanation, the peripheral area PA is shown enlarged from its actual size.

In the processing from step S11 onwards, the control device 100 causes the rotation holding unit 20 to continue rotating the workpiece W at the first rotation speed until the rotation speed is adjusted. The first rotation speed is preset to a rotation speed at which the removal liquid does not splash excessively when supplied (discharged) to the surface Wa of the workpiece W. The first rotation speed may be 500 rpm to 2000 rpm, 700 rpm to 1800 rpm, or 1000 rpm to 1500 rpm.

Next, the control device 100 executes step S12. In step S12, for example, the control device 100 controls the liquid delivery unit 43 of the removal liquid supply unit 40 to start discharging the removal liquid toward the peripheral region of the treatment liquid film. Specifically, the control device 100 switches the opening/closing valve V2 of the liquid delivery unit 43 from a closed state to an open state. As a result, the removal liquid starts to be discharged from the nozzle 41 arranged in the first discharge position, and the removal liquid starts to be supplied to the peripheral region. That is, the first process described above is started.

Next, the control device 100 executes step S13. In step S13, for example, the control device 100 waits until a predetermined discharge time has elapsed since starting to discharge the removal liquid. The discharge time is determined in advance and is set to, for example, about 0.3 to 3.0 seconds. FIG. 7(b) illustrates an example in which the removal liquid Lr is supplied from the nozzle 41 to the peripheral area PA of the treatment liquid film R while the workpiece W is rotating. As the removal liquid Lr is supplied to the peripheral area PA, the peripheral area PA of the treatment liquid film R is softened (begins to dissolve) by the removal liquid.

Next, the control device 100 executes step S14. In step S14, for example, the control device 100 moves the nozzle 41 by the drive unit 44 so that the arrival area AR of the removal liquid from the nozzle 41 in a state where the removal liquid is being discharged moves from the peripheral area of the film of the processing liquid to a position outside the peripheral edge Wb of the workpiece W. By moving the arrival area AR to a position outside the peripheral edge Wb, a state in which the removal liquid is not supplied to the peripheral area of the film of the processing liquid is started (the second process described above is started). As a result, the process executed by the control device 100 transitions from the first process to the second process. FIG. 8(a) illustrates an example in which the removal liquid Lr from the nozzle 41 is discharged outside the workpiece W while the workpiece W is rotating, and the removal liquid is not supplied to the peripheral area PA of the film R of the processing liquid.

Next, the control device 100 executes steps S15 and S16. In step S15, for example, the control device 100 waits until a predetermined waiting time has elapsed. The waiting time is predetermined and is set, for example, to about 0.5 to 3.0 seconds. The waiting time may be set to the same value as the ejection time, or may be set to a value different from the ejection time. In step S16, for example, the control device 100 determines whether the number of repetitions of one loop of processing (one set of processing) including the first process and the second process has reached a predetermined number. This predetermined number is set in advance to a value of 2 or more.

In step S16, if it is determined that the number of repetitions of one loop process has not reached the predetermined number (step S16: NO), the process executed by the control device 100 proceeds to step S17. In step S17, for example, the control device 100 moves the nozzle 41 by the drive unit 44 so that the arrival area AR of the removal liquid from the nozzle 41 in a state in which the removal liquid is being discharged moves from a position outside the workpiece W to the peripheral area of the film of the treatment liquid (so as to overlap the peripheral area). As the arrival area AR moves to the peripheral area of the film of the treatment liquid, a state in which the removal liquid is supplied to the peripheral area of the film of the treatment liquid is started (the state in which the removal liquid is supplied is resumed). As a result, the process executed by the control device 100 transitions from the second process to the first process.

After step S17 is executed, the process executed by the control device 100 returns to step S13. Thereafter, the control device 100 repeats the series of processes from steps S13 to S16 (S17) until the number of times one loop of processes is executed reaches the above-mentioned predetermined number of times. As a result, one loop of processes including the first process and the second process is executed repeatedly two or more times. In this case, the control device 100 controls the liquid processing unit U1 to execute multiple first processes and multiple second processes alternately, one at a time. In this control, the number of times the multiple first processes are executed is the same as the number of times the multiple second processes are executed.

The number of repetitions of one loop of processing may be set to 30 times or less, 25 times or less, 20 times or less, or 15 times or less from the viewpoint of processing efficiency. The number of repetitions of one loop of processing may be set to 2 times or more, 4 times or more, 6 times or more, or 8 times or more from the viewpoint of suppressing the influence on the film thickness distribution due to the intermittent removal processing. The number of repetitions of one loop of processing is set to, for example, 2 to 30 times, or 4 to 20 times.

By supplying the removal liquid to the peripheral region of the treatment liquid film, the peripheral region is softened and dissolved. As the supply of the removal liquid to the peripheral region continues, the removal liquid and the components in the treatment liquid mix to form a mixed layer in the peripheral region of the workpiece W. As the workpiece W rotates, the unsolidified part of the treatment liquid film is pulled to the periphery and the mixed layer builds up. As a result, a phenomenon in which the film thickness rises at the end of the treatment liquid film after the peripheral region is removed can occur. In the first process of the intermittent removal process described above, a mixed layer is also formed in the peripheral region of the surface Wa of the workpiece W.

In the second process following the first process, the workpiece W rotates without being supplied with the removal liquid, and the mixed layer is discharged outside the workpiece W. By executing the second process, the height of the piled-up mixed layer can be reduced. In the first stage of the intermittent removal process, the control device 100 may rotate the workpiece W by the rotating and holding unit 20 in the second process so that a part of the film of the processing liquid softened by the removal liquid is discharged outside the workpiece W. In the second stage of the intermittent removal process, the dissolution (softening) of the film progresses, so that a liquid in which the component of the film of the processing liquid dissolved by the removal liquid and the removal liquid are mixed can be formed. Therefore, the control device 100 may rotate the workpiece W by the rotating and holding unit 20 in the second process so that the mixed liquid is discharged outside the workpiece W.

If it is determined in step S16 that the number of times the process of one loop has been executed has reached a predetermined number (step S16: YES), the process executed by the control device 100 proceeds to step S18. In step S18, the control device 100 causes the drive unit 44 to move the nozzle 41 in a state in which the removal liquid is being ejected so that the arrival area AR overlaps the peripheral area. Hereinafter, in step S18, the position of the nozzle 41 arranged so that the arrival area AR is located in the peripheral area is referred to as the "second ejection position". The arrival area AR of the removal liquid from the nozzle 41 arranged in the second ejection position may be located outside the arrival area AR of the removal liquid from the nozzle 41 arranged in the first ejection position in the first process included in the intermittent removal process, or may be approximately the same.

Next, the control device 100 executes step S19. In step S19, for example, the control device 100 waits until a predetermined supply time (predetermined time) has elapsed since the control device 100 moved the nozzle 41 to the second discharge position. The supply time is preset to a time that allows the removal liquid to dissolve the undissolved portion of the peripheral area of the film of the treatment liquid in the intermittent removal process in which the first process and the second process are alternately repeated. The predetermined supply time may be longer than the above-mentioned discharge time (the execution time of the first process) during which the control device 100 waits in step S13. The supply time may be about 2 to 30 times the above-mentioned discharge time (the execution time of the first process).

Next, the control device 100 executes step S20. In step S20, for example, the control device 100 controls the liquid delivery unit 43 of the removal liquid supply unit 40 to stop the ejection of the removal liquid from the nozzle 41. Specifically, the control device 100 stops the ejection of the removal liquid from the nozzle 41 by switching the opening/closing valve V2 of the liquid delivery unit 43 from an open state to a closed state. As described above, after executing the intermittent removal process, the control device 100 causes the liquid processing unit U1 to execute a continuous removal process in which the removal liquid is supplied to the peripheral region of the film of the processing liquid (the peripheral region of the surface Wa of the workpiece W) while rotating the workpiece W for a predetermined supply time.

Next, the control device 100 executes steps S21 and S22. In step S21, for example, the control device 100 controls the rotation holding unit 20 to increase the rotation speed of the workpiece W from the first rotation speed to the second rotation speed. In step S22, for example, the control device 100 accelerates the rotation of the workpiece W to the second rotation speed and then waits until a predetermined shake-off time has elapsed. The second rotation speed and the shake-off time are each preset to a value that allows the removal solution and dissolved material remaining on the surface Wa of the workpiece W to be discharged outside the workpiece W. The second rotation speed is higher than the first rotation speed, and is, for example, about 1500 rpm to 3000 rpm. Figure 8 (b) illustrates the rotation of the workpiece W after the discharge of the removal solution Lr from the nozzle 41 has stopped.

Next, the control device 100 executes step S23. In step S23, for example, the control device 100 controls the rotation holding unit 20 to stop the rotation of the workpiece W. By executing the above series of processes, the peripheral region of the film R of the processing liquid on the surface Wa of the workpiece W is removed as shown in FIG. 8(b). In other words, a film R of the processing liquid with the peripheral region removed is formed on the surface Wa of the workpiece W.

The above-described series of processes is an example and can be modified as appropriate. In the above-described series of processes, the control device 100 may execute one step and the next step in parallel, or may execute each step in an order different from the above-described example. The control device 100 may, for example, execute step S12 and then execute step S11. That is, the control device 100 may also cause the liquid processing unit U1 to start the first process for the first process executed by moving the nozzle 41, which has ejected the removal liquid outside the periphery Wb of the workpiece W, to the first ejection position by the drive unit 44.

The control device 100 may omit any of the steps, or may execute a process different from the above-mentioned example in any of the steps. The control device 100 may omit, for example, step S21. The control device 100 may omit, for example, steps S18 and S19 (the continuous removal process may be omitted). In this case, following the intermittent removal process, the control device 100 may control the liquid processing unit U1 to continue stopping the discharge of the removal liquid from the nozzle 41 and rotate the workpiece W for the shake-off time.

The control device 100 may switch between the first process and the second process by switching the open/close state of the on-off valve V2 of the liquid delivery unit 43 while maintaining the nozzle 41 in a state in which the removal liquid can be discharged toward the peripheral region of the treatment liquid film. FIG. 9 is a flowchart showing another example of a series of processes executed by the control device 100 to remove the peripheral region of the treatment liquid film. In this series of processes, the control device 100 executes steps S31 to S33, similar to steps S11 to S13 of the series of processes shown in FIG. 6. FIG. 10(a) illustrates an example in which the removal liquid Lr is supplied to the peripheral region PA of the treatment liquid film R after execution of step S32.

When a predetermined discharge time has elapsed in step S33, the control device 100 executes step S34. In step S34, for example, the control device 100 controls the liquid delivery unit 43 of the removal liquid supply unit 40 to stop the discharge of the removal liquid from the nozzle 41 while maintaining the nozzle 41 at the first discharge position. Specifically, the control device 100 stops the discharge of the removal liquid from the nozzle 41 by switching the opening and closing valve of the liquid delivery unit 43 from an open state to a closed state while the nozzle 41 is placed at the first discharge position where the removal liquid can be supplied to the peripheral area of the film of the processing liquid. Then, the control device 100 executes steps S35 and S36 in the same manner as steps S15 and S16. While step S35 is being executed, the control device 100 may cause the drive unit 34 to maintain the state in which the nozzle 41 is placed at the first discharge position. FIG. 10B illustrates a state in which the removal liquid Lr is not supplied to the peripheral area PA of the film R of the processing liquid while the nozzle 41 is placed at the first discharge position.

If it is determined in step S36 that the number of repetitions of the intermittent removal process has not reached the predetermined number (step S36: NO), the process executed by the control device 100 returns to step S32. In step S32, for example, the control device 100 controls the liquid delivery unit 43 of the removal liquid supply unit 40 to start (resume) the ejection of the removal liquid from the nozzle 41 while maintaining the nozzle 41 in the first ejection position. Specifically, the control device 100 switches the opening/closing valve V2 of the liquid delivery unit 43 from a closed state to an open state while the nozzle 41 is placed in the first ejection position where the removal liquid can be supplied to the peripheral region of the treatment liquid film, thereby starting the ejection of the removal liquid from the nozzle 41.

Then, the control device 100 repeats the series of processes from step S32 to S36 until the number of times that one loop of processes including the first process and the second process is executed reaches a predetermined number. If it is determined in step S36 that the number of times that one loop of processes is repeated reaches a predetermined number (step S36: YES), the control device 100 executes steps S37 and S38. In step S37, for example, the control device 100 moves the nozzle 41, in a state in which the ejection of the removal liquid is stopped, to the above-mentioned second ejection position by the drive unit 44. In step S38, for example, the control device 100 switches the opening and closing valve V2 from a closed state to an open state to start ejecting the removal liquid from the nozzle 41. Then, the control device 100 executes steps S39 to S43 in the same manner as steps S19 to S23. By executing the above series of processes, the peripheral area of the film of the treatment liquid on the surface Wa of the workpiece W is removed.

In the intermittent removal process included in the series of processes shown in FIG. 6, the process executed by the control device 100 transitions from the second process to the first process as the arrival area AR of the removal liquid from the nozzle 41 ejecting the removal liquid moves from outside the periphery Wb of the workpiece W to the peripheral area of the film of treatment liquid. On the other hand, in the intermittent removal process included in the series of processes shown in FIG. 9, the arrival area AR (the area where the ejected removal liquid is expected to arrive) remains in the peripheral area, and the opening/closing valve V2 that opens and closes the flow path to the nozzle 41 transitions from a closed state to an open state, and the process executed by the control device 100 transitions from the second process to the first process.

In the intermittent removal process included in the series of processes shown in FIG. 6, the process executed by the control device 100 transitions from the first process to the second process as the arrival area AR moves from the peripheral area of the treatment liquid film to the outside of the peripheral area Wb of the workpiece W. On the other hand, in the intermittent removal process included in the series of processes shown in FIG. 9, the process executed by the control device 100 transitions from the first process to the second process as the opening/closing valve V2 transitions from an open state to a closed state while the arrival area AR is located in the peripheral area. The above-mentioned modified example of the series of processes shown in FIG. 6 may also be applied to the series of processes shown in FIG. 9.

In part of the series of processes shown in FIG. 6, part of the series of processes shown in FIG. 9 may be applied. In all of the multiple second processes included in the intermittent removal process shown in FIG. 6, when starting (resuming) the second process, the control device 100 may switch the opening and closing valve V2 from an open state to a closed state with the nozzle 41 disposed at the first discharge position. In this case, before starting the first process (during execution of the second process), the control device 100 may move the nozzle 41 by the drive unit 44 so that the arrival area AR is located outside the periphery Wb, and cause the removal liquid supply unit 40 to start discharging the removal liquid from the nozzle 41. In part of the multiple second processes, the control device 100 may move the arrival area AR of the removal liquid outside the periphery Wb to start the second process, and in the remaining part, the control device 100 may switch the opening and closing valve V2 from an open state to a closed state with the nozzle 41 disposed at the first discharge position to start the second process.

In all of the multiple first processes included in the intermittent removal process shown in FIG. 6, the control device 100 may switch the opening/closing valve V2 from a closed state to an open state when starting (resuming) the first process with the nozzle 41 disposed at the first discharge position. In this case, in order to end the first process, the control device 100 moves the nozzle 41 to the drive unit 44 so that the arrival area AR of the removal liquid is outside the periphery Wb. Then, before starting the first process, the control device 100 may stop the removal liquid supply unit 40 from discharging the removal liquid, and then move the nozzle 41 to the first discharge position by the drive unit 44. In some of the multiple first processes, the control device 100 may start the first process by moving the arrival area AR of the removal liquid to the peripheral area of the film of the treatment liquid, and in the remaining part, the control device 100 may start the first process by switching the opening/closing valve V2 from a closed state to an open state with the nozzle 41 disposed at the first discharge position.

Next, with reference to Figures 11 and 12, the effect on the film thickness distribution of the intermittent removal process in which the first process and the second process are alternately performed will be described. The film thickness distribution is a distribution that indicates the change in the thickness (film thickness) of the film of the treatment liquid with respect to the measurement position on the diameter on the surface Wa of the workpiece W. Comparative Example 1, Comparative Example 2, Example 1, and Example 2 were each prepared under the following conditions.

In Comparative Example 1, the intermittent removal process was not performed, and the removal liquid was continuously discharged onto the peripheral region of the treatment liquid film for 20 seconds. Also, in Comparative Example 1, in the stage of forming a treatment liquid film on the surface Wa before removing the peripheral region, the treatment liquid on the surface Wa was dried by rotating for 120 seconds after the supply of the treatment liquid was stopped. In Comparative Example 2, as in Comparative Example 1, the intermittent removal process was not performed, and the removal liquid was continuously discharged onto the peripheral region of the treatment liquid film for 20 seconds. Also, in Comparative Example 2, in the stage of forming a treatment liquid film, the treatment liquid on the surface Wa was dried by rotating for 70 seconds after the supply of the treatment liquid was stopped.

In Example 1, one loop of processing including the first and second processes was repeated three times, and then a continuous removal process was performed in which the removal liquid was continuously supplied to the peripheral area of the film of the processing liquid for 10 seconds. The execution time of each of the first and second processes was 1 second. In Example 1, a film of the processing liquid was formed in the same manner as in Comparative Example 1. In Example 2, one loop of processing including the first and second processes was repeated 10 times, and then a continuous removal process was performed in which the removal liquid was continuously supplied to the peripheral area of the film of the processing liquid for 5 seconds. The execution time of each of the first and second processes was 1 second. In Example 2, a film of the processing liquid was formed in the same manner as in Comparative Example 2.

To evaluate the rise in film thickness at the edge of the treatment liquid film after the peripheral region has been removed, the "hump height" and "edge bounce" defined as follows were evaluated. The hump height is the maximum film thickness between the radial positions of 148 mm and 150 mm on the surface Wa of the workpiece W, which has a diameter of 300 mm. The edge bounce is the difference between the film thickness at the radial position of 147 mm and the film thickness at the radial position of 145 mm.

In FIG. 11(a), the evaluation results of the hump heights in Comparative Example 1, Comparative Example 2, Example 1, and Example 2 are shown in a bar graph. In the graph in FIG. 11(a), the evaluation results are shown as relative values when the hump height in Comparative Example 1 is set to 100%. In FIG. 11(b), the evaluation results of the edge bounce in Comparative Example 1, Comparative Example 2, Example 1, and Example 2 are shown in a bar graph. In the graph in FIG. 11(b), the evaluation results are shown as relative values when the edge bounce in Comparative Example 1 is set to 100%.

The results of Comparative Example 1 and Comparative Example 2 show that when the drying time when forming the film of the treatment liquid is shortened, there is a possibility that the film thickness will rise more at the end of the film after the peripheral region has been removed. This is thought to be due to the fact that when the drying time is short, the film of the treatment liquid contains more solvent when performing the process of removing the peripheral region compared to when the drying time is long. The results of Comparative Example 1 and Example 1 show that by alternately performing the first process and the second process, the rise in film thickness at the end of the film after the peripheral region has been removed is reduced.

From the results of Comparative Example 1 and Example 2, it can be seen that even if the drying time is shortened (even if a large amount of solvent is contained in the film of the treatment liquid when the peripheral region is removed), the intermittent removal process reduces the rise in film thickness at the end of the film after the peripheral region is removed. In addition, in Comparative Example 1, the total time of the drying process and the process (removal process) for removing the peripheral region is 140 seconds, while the corresponding total time in Example 2 is 95 seconds. In other words, it can be seen that the rise in film thickness at the end of the film of the treatment liquid after the peripheral region is removed can be reduced while shortening the total process time for forming the film of the treatment liquid and the execution time of the removal process.

Figure 12(a) shows the measurement results of the film thickness distribution in Comparative Example 1, and Figure 12(b) shows the measurement results of the film thickness distribution in Example 2. In Figures 12(a) and 12(b), the measurement results are plotted so that the vertical scale is the same. In Figures 12(a) and 12(b), the difference between the maximum and minimum values of the film thickness distribution is shown as "Ra". The difference Ra in the measurement results shown in Figure 12(b) is about 0.8 times the difference Ra in the measurement results shown in Figure 12(a). In other words, it can be seen that the difference Ra, which indicates the difference between the maximum and minimum values in the film thickness distribution, is reduced by alternately repeating a state in which the removing liquid is supplied and a state in which the removing liquid is not supplied.

[Effects of the embodiment]
The substrate processing method according to the above embodiment includes performing an intermittent removal process for removing a peripheral region of a film formed by a processing liquid on the front surface Wa of the workpiece W. The intermittent removal process includes alternately performing a first process for supplying a removing liquid for removing the film from the nozzle 41 to the peripheral region while rotating the workpiece W, and a second process for maintaining a state in which, after performing the first process, the removing liquid is not supplied to the peripheral region from the nozzle 41 while rotating the workpiece W.

In order to remove the peripheral region of the film of the processing liquid, conventionally, the peripheral region is removed by continuously supplying the removing liquid to the peripheral region. While the removing liquid is being supplied to the peripheral region, the components in the film of the processing liquid and the removing liquid mix to form a mixed layer on the peripheral region of the substrate, and the mixed layer builds up. As the film of the processing liquid dries in this state, the film thickness at the end of the film after the peripheral region is removed becomes thicker than other regions. In contrast, in the above-mentioned substrate processing method, a state in which the removing liquid is supplied to the peripheral region and a state in which the removing liquid is not supplied to the peripheral region are alternately repeated, so that the time for supplying the removing liquid to the peripheral region is shorter than when the removing liquid is continuously supplied, and the formation of the mixed layer is suppressed. In addition, by rotating the workpiece W in a state in which the removing liquid is not supplied, the mixed layer can be discharged outside the workpiece W during the process of removing the peripheral region, so that the buildup of the mixed layer can be suppressed. Therefore, it is possible to reduce the buildup of the film thickness at the end of the film of the processing liquid after the peripheral region is removed.

The above substrate processing method may start at least one first process performed in the intermittent removal process by moving the nozzle 41 so that the arrival area AR of the removal liquid from the nozzle 41 in a state where the removal liquid is being discharged moves from a position outside the periphery Wb of the workpiece W to the peripheral area of the film of the treatment liquid. In this case, the number of times that the nozzle 41, which has stopped discharging, is transitioned to a state where the removal liquid is being discharged in order to start the first process can be reduced. As a result, it is possible to reduce the frequency of occurrence of malfunctions that may occur when the nozzle 41 starts discharging the removal liquid. For example, it is possible to reduce the frequency of occurrence of malfunctions in which the treatment liquid is discharged from the nozzle 41 in an unintended direction when the opening/closing valve V2 is transitioned to an open state to start discharging.

In the above substrate processing method, with the nozzle 41 positioned at a position where the removal liquid can be supplied to the peripheral region, the opening/closing valve V2, which opens and closes the flow path that sends the removal liquid to the nozzle 41, may be switched from a closed state to an open state to start at least one first process executed in the intermittent removal process. In this case, the period during which the removal liquid is continuously discharged without being supplied to the processing liquid film before the first process is started can be reduced. As a result, it is possible to reduce the amount of removal liquid discharged (total amount of discharged) in the intermittent removal process including the second process in which the removal liquid is not supplied.

The above substrate processing method may start at least one second process performed in the intermittent removal process by moving the nozzle 41 so that the arrival area AR of the removal liquid from the nozzle 41 in a state where the removal liquid is being discharged moves from the peripheral area of the film of the treatment liquid to a position outside the peripheral edge Wb of the workpiece W. In this case, the number of times that the nozzle 41 discharging the removal liquid is transitioned to a state where discharge is stopped in order to start the second process can be reduced. As a result, it is possible to reduce the frequency of occurrence of malfunctions that may occur due to the nozzle 41 stopping the discharge of the removal liquid. For example, it is possible to reduce the frequency of occurrence of malfunctions in which the treatment liquid is discharged from the nozzle 41 in an unintended direction when the opening/closing valve V2 is transitioned to a closed state to stop discharge.

In the above substrate processing method, with the nozzle 41 positioned at a position where the removal liquid can be supplied to the peripheral region, the opening/closing valve V2, which opens and closes the flow path that sends the removal liquid to the nozzle 41, may be switched from an open state to a closed state to start at least one second process performed in the intermittent removal process. In this case, after the start of the second process, the period during which the removal liquid is continuously discharged without being supplied to the processing liquid film can be reduced. As a result, it is possible to reduce the amount of removal liquid discharged (total amount of discharged) in the intermittent removal process including the second process in which the removal liquid is not supplied.

The above substrate processing method may further include continuing to supply the removal liquid to the peripheral region for a predetermined time while rotating the workpiece W after performing the intermittent removal process. In this case, by continuing to supply the removal liquid for a predetermined time after performing the intermittent removal process, the time required to remove a target amount of the peripheral region of the processing liquid film is shortened. As a result, it is possible to achieve both a reduction in the buildup of the film thickness at the ends and processing efficiency.

The second process may include rotating the workpiece W so that a portion of the treatment liquid film softened by the removal liquid is discharged outside the workpiece W. A portion of the film softened by the removal liquid remains in the peripheral region of the workpiece W, which may cause the film thickness to bulge. In the above method, a portion of the film softened by the removal liquid is discharged outside the workpiece W, thereby suppressing the build-up of the mixed layer in the peripheral region of the surface Wa. As a result, it is possible to reduce the bulge in film thickness at the end of the film after the peripheral region is removed.

The second process may include rotating the workpiece W so that a liquid obtained by mixing the components of the treatment liquid film dissolved by the removal liquid with the removal liquid is discharged outside the workpiece W. If the mixed liquid remains in the peripheral region of the workpiece W, a rise in the film thickness may occur. In the above method, the mixed liquid obtained by mixing the components dissolved by the removal liquid with the removal liquid is discharged outside the workpiece W, so that the buildup of the mixed layer in the peripheral region of the surface Wa is suppressed. As a result, it is possible to reduce the rise in the film thickness at the end of the film after the peripheral region is removed.

1...substrate processing system, 2...coating and developing apparatus, U1...liquid processing unit, 20...rotating holder, 30...processing liquid supply section, 40...removal liquid supply section, 41...nozzle, 44...drive section, L2...liquid supply pipe, V2...opening and closing valve, 100...control device, W...workpiece, Wa...surface, Wb...periphery, AR...reach area.

Claims (13)

performing a removal process for removing a peripheral region of a film formed by a processing liquid on a surface of a substrate so as to expose an area underneath the film;
The removal process includes an intermittent removal process , a continuous removal process, and a shake-off process ,
The intermittent removal process includes:
a first process of supplying a removal liquid for removing the film from a nozzle onto the peripheral region while rotating the substrate;
and alternately performing a second process in which, after the first process is performed , a state in which the removing liquid is not supplied from the nozzle to the peripheral region is maintained while rotating the substrate,
the removal liquid is a solvent capable of dissolving the film,
When the execution of the second process is completed, the intermittency removal process is completed,
the continuous removal process includes, after performing the intermittent removal process, continuing to supply the removing liquid to the peripheral region for a predetermined time while rotating the substrate,
The substrate processing method includes rotating the substrate at a rotational speed greater than the rotational speed of the substrate in each of the second processes of the intermittent removal process after the continuous removal process, without ejecting the removal liquid . The substrate processing method according to claim 1, wherein the removal liquid is continuously discharged from the nozzle at least during the period during which the intermittent removal process is performed, from the start of the first process to the end of the last first process. The substrate processing method according to claim 1 , wherein the predetermined time is longer than a duration of each of the first steps in the intermittent removal processes. The substrate processing method according to any one of claims 1 to 3, wherein a reach area of the removing liquid in the continuous removal process is set at a position farther from the center of the substrate than a reach area of the removing liquid in each of the first processes in the intermittent removal process. 5. The substrate processing method according to claim 1 , wherein the second process includes rotating the substrate so as to discharge a portion of the film softened by the removing liquid outside the substrate. 6. The substrate processing method according to claim 1, wherein the second process includes rotating the substrate so as to discharge a mixture of the component of the film dissolved by the removing liquid and the removing liquid outside the substrate. A computer-readable storage medium storing a program for causing an apparatus to execute the substrate processing method according to any one of claims 1 to 6 . a liquid processing unit including a spin holder that holds and rotates a substrate, a processing liquid supplying unit that supplies a predetermined processing liquid to the substrate held by the spin holder, and a removing liquid supplying unit that includes a nozzle and supplies a removing liquid from the nozzle to the substrate held by the spin holder;
a control unit for controlling the liquid processing unit;
the control unit controls the liquid processing unit to form a film of the processing liquid on the surface of the substrate, and controls the liquid processing unit to perform a removal process to remove a peripheral region of the film so as to expose an area below the film;
The removal process includes an intermittent removal process , a continuous removal process, and a shake-off process ,
The intermittent removal process includes:
a first process of supplying the removing liquid from the nozzle by the removing liquid supply unit to the peripheral region while rotating the substrate by the spin holder;
and a second process in which the removing liquid supply unit is caused to maintain a state in which the removing liquid is not supplied from the nozzle to the peripheral region while rotating the substrate by the spin holding unit after the first process is performed ,
the removal liquid is a solvent capable of dissolving the film,
When the execution of the second process is completed, the intermittency removal process is completed,
the continuous removal process includes, after performing the intermittent removal process, continuing to supply the removing liquid to the peripheral region for a predetermined time while rotating the substrate,
The shake-off process is a process of rotating the substrate at a rotational speed higher than the rotational speed of the substrate in each of the second processes of the intermittent removal process without ejecting the removal liquid, separate from the continuous removal process, in a substrate processing apparatus. 9. The substrate processing apparatus of claim 8, wherein the control unit controls the liquid processing unit so that the removal liquid continues to be ejected from the nozzle at least during a period during which the intermittent removal process is performed, from the start of a first run of the first process to the end of the last run of the first process. The substrate processing apparatus according to claim 8 , wherein the predetermined time is longer than a duration of each of the first processes in the intermittent removal process. The substrate processing apparatus according to any one of claims 8 to 10, wherein a reach area of the removal liquid in the continuous removal process is set at a position farther from the center of the substrate than a reach area of the removal liquid in each of the first processes of the intermittent removal process. The substrate processing apparatus according to any one of claims 8 to 11 , wherein the second process includes rotating the substrate by the rotating holder so as to discharge a portion of the film softened by the removing liquid outside the substrate. The substrate processing apparatus according to any one of claims 8 to 12, wherein the second process includes rotating the substrate by the rotating holder so as to discharge a liquid mixture of the component of the film dissolved by the removing liquid and the removing liquid outside the substrate.

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