JP7503444B2 - 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-type film forming method that includes a process of forming a coating film by applying a chemical solution onto the main surface of a substrate to be treated while rotating the substrate to be treated, a process of drying the coating film while rotating the substrate to be treated, and a process of blowing air or nitrogen gas toward a predetermined area of the coating film during the drying process.

JP 2003-37053 A

The present disclosure provides a substrate processing method, a storage medium, and a substrate processing apparatus that enable local adjustment of the thickness of a coating formed on a substrate surface.

A substrate processing method according to one aspect of the present disclosure includes supplying a processing liquid to a surface of the substrate while rotating the substrate so as to coat the surface of the substrate with the processing liquid, and after supplying the processing liquid, aspirating gas in the vicinity of the surface of the substrate through a nozzle including an opening having a width smaller than half the diameter of the substrate, with the opening facing the surface of the substrate.

The present disclosure provides a substrate processing method, a storage medium, and a substrate processing apparatus that enable local adjustment of the thickness of a coating formed on a substrate surface.

FIG. 1 is a schematic perspective view showing an example of a substrate processing system. FIG. 2 is a side view illustrating an example of a coating and developing apparatus. FIG. 3 is a schematic diagram illustrating an example of the liquid processing unit. Fig. 4(a) is a schematic diagram showing an example of an opening of a suction nozzle, and Fig. 4(b) is a schematic diagram for explaining an example of the positional relationship between the suction nozzle and a workpiece. FIG. 5 is a block diagram illustrating an example of a hardware configuration of the control device. FIG. 6 is a flow chart showing an example of a liquid processing method. FIG. 7 is a flow chart showing an example of a coating process of a treatment liquid. FIG. 8 is a flowchart showing an example of a coating forming process. FIG. 9 is a graph showing an example of the change over time in the rotation speed of the workpiece during liquid processing. FIG. 10 is a graph showing an example of the film thickness measurement results. FIG. 11 is a schematic diagram for explaining a phenomenon caused by gas suction from a suction nozzle. Fig. 12A is a graph showing an example of a film thickness measurement result according to a comparative example, and Fig. 12B is a graph showing an example of a film thickness measurement result according to an embodiment. Fig. 13A is a diagram showing a film thickness distribution according to a comparative example, and Fig. 13B is a diagram showing an example of a film thickness measurement portion according to the embodiment. FIG. 14 is a graph showing an example of the change over time in the rotation speed of the workpiece during liquid processing according to the first modification. 15A is a graph showing an example of the film thickness measurement results when the rotation speed is constant, and FIG 15B is a graph showing an example of the film thickness measurement results when the rotation speed is reduced. FIG. 16 is a schematic diagram for explaining an example of a liquid processing method according to Modifications 2 and 3. In FIG. 17(a) is a graph showing an example of a film thickness measurement result when the suction nozzle opening is fixed in a fixed position, and FIG 17(b) is a graph showing an example of a film thickness measurement result when the suction nozzle opening is moved back and forth. 18(a) is a graph showing an example of a film thickness measurement result when two locations are aspirated in the order from the outer periphery to the center, and FIG. 18(b) is a graph showing an example of a film thickness measurement result when two locations are aspirated in the order from the center to the outer periphery.

Various exemplary embodiments are described below.

A substrate processing method according to one exemplary embodiment includes supplying a processing liquid to a surface of the substrate while rotating the substrate so as to apply the processing liquid onto the surface of the substrate, and after supplying the processing liquid, aspirating gas in the vicinity of the surface of the substrate through a nozzle including an opening having a width smaller than half the diameter of the substrate, with the opening facing the surface of the substrate.

In this substrate processing method, gas near the surface of the substrate is sucked in through an opening with a width smaller than half the diameter of the substrate. After the processing liquid is supplied, the solvent contained in the processing liquid supplied onto the surface of the substrate evaporates, forming a coating of the processing liquid. In the process of forming the coating of the processing liquid, the nozzle sucks in gas near the surface of the substrate, thereby promoting the evaporation of the solvent at the location where the gas is sucked in more than in other areas, and the thickness of the coating can be varied. In this substrate processing method, because the width of the nozzle opening is small, this variation in thickness can be caused at some locations within the substrate surface. This makes it possible to locally adjust the thickness of the coating formed on the substrate surface.

Aspirating gas through the nozzle opening may include aspirating gas through the opening with the nozzle positioned so that the distance between the opening and the surface of the substrate is greater than 3 mm and less than 30 mm. In this case, it is possible to more reliably cause film thickness variations due to gas aspirate and to suppress the occurrence of film thickness unevenness due to turbulence in the air flow caused by gas aspirate.

The width of the nozzle opening may be smaller than the distance when gas is drawn through the opening. In this case, it is possible to further suppress the occurrence of unevenness in the film thickness due to turbulence in the air flow caused by the gas being drawn in.

The substrate processing method may further include rotating the substrate until a predetermined time has elapsed since the supply of the processing liquid is stopped. Suctioning the gas through the opening may include suctioning the gas through the opening in the first half of the predetermined time. In the first half of the period during which the substrate is rotated after the supply of the processing liquid, the solvent in the processing liquid evaporates more rapidly, and in the second half, the volatilization of the solvent slows down. Therefore, in the method, by suctioning the gas in the first half, it is possible to more reliably cause film thickness variations due to the suction of the gas.

The rotation speed of the substrate when rotating the substrate for a given time may be lower than the rotation speed of the substrate when supplying the processing liquid. In this case, gas is sucked in near the surface of the substrate when rotating at a rotation speed lower than the rotation speed of the substrate when supplying the processing liquid. By slowing down the rotation of the substrate, the speed of the air flow generated in association with the rotation of the substrate near the surface of the substrate slows down. Therefore, with the above method, more gas can be sucked in in a short suction time, making it possible to efficiently adjust the film thickness by suction.

The substrate processing method may further include rotating the substrate until a predetermined time has elapsed since the supply of the processing liquid is stopped. Aspirating the gas through the opening may include aspirating the gas through the opening during a portion of the predetermined time. The rotation speed of the substrate when the gas is being aspirated during the predetermined time may be lower than the rotation speed of the substrate during at least a portion of the portion of the predetermined time when the gas is not being aspirated. By slowing down the rotation of the substrate, the speed of the air flow generated in association with the rotation of the substrate near the surface of the substrate slows down. Therefore, in the above method, more gas can be aspirated in a short suction time, and efficient film thickness adjustment by suction becomes possible.

The step of drawing gas through the opening may include drawing gas through the opening while moving the opening back and forth in a direction along the surface of the substrate. In this case, the position on the surface of the substrate toward which the nozzle opening faces is not fixed, and it is possible to level out the tendency for film thickness fluctuations caused by the fixed position.

The step of drawing gas from the opening may include performing a first suction process to draw gas from an opening facing a position that is a first distance away from the center of rotation of the substrate along the surface of the substrate, and performing a second suction process after the first suction process to draw gas from an opening facing a position that is a second distance away from the center of rotation of the substrate along the surface of the substrate that is greater than the first distance. It is believed that the solvent of the processing liquid evaporates faster on the central side of the substrate than on the peripheral side of the substrate. In the above method, the gas is drawn from the central side to the peripheral side of the substrate in sequence, which makes it possible to adjust the film thickness more reliably when adjusting the film thickness at at least two locations.

The storage medium according to one exemplary embodiment is a computer-readable storage medium that stores a program for causing an apparatus to execute the substrate processing method.

A substrate processing apparatus according to an exemplary embodiment includes a liquid processing unit having a rotating holder that holds and rotates a substrate, a processing liquid supplying unit that supplies processing liquid to the surface of the substrate held by the rotating holder, and a gas suction unit that includes a nozzle with an opening with a width smaller than half the diameter of the substrate and sucks gas through the opening, and a control unit that controls the liquid processing unit. The control unit sequentially supplies processing liquid to the surface of the substrate by the processing liquid supplying unit while rotating the substrate by the rotating holder so as to apply processing liquid to the surface of the substrate, and after supplying the processing liquid, causes the gas suction unit to suck gas in the vicinity of the surface of the substrate through the opening with the nozzle positioned so that the opening faces the surface of the substrate. In this substrate processing apparatus, as in the above substrate processing method, it is possible to locally adjust the thickness of the coating formed on the surface of the substrate.

One embodiment will be described below with reference to the drawings. In the description, identical elements or elements having the same functions are given the same reference numerals, and duplicate descriptions will be omitted.

The substrate processing system 1 shown in FIG. 1 is a system that forms a photosensitive coating on a workpiece W, exposes the photosensitive coating, and develops the photosensitive coating. The workpiece W to be processed is, for example, a substrate, or a substrate on which a film or circuit or the like has been formed by a predetermined process. One example of the substrate included in the workpiece W is a wafer containing silicon. The workpiece W (substrate) may be formed in a circular shape. The workpiece W to be processed may be a glass substrate, a mask substrate, an FPD (Flat Panel Display), or the like, or may be an intermediate product obtained by a predetermined process on such a substrate. The photosensitive coating is, for example, a resist film.

The substrate processing system 1 includes a coating/developing device 2 and an exposure device 3. The coating/developing device 2 applies resist (chemical solution) to the surface of the workpiece W (substrate) to form a resist film before exposure processing by the exposure device 3, and develops the resist film after exposure processing. The exposure device 3 is a device that exposes the resist film (photosensitive coating) formed on the workpiece W. Specifically, the exposure device 3 irradiates the exposure target portion of the resist film with energy rays by a method such as immersion exposure.

[Substrate Processing Apparatus]
Hereinafter, a configuration of a coating/developing apparatus 2 will be described as an example of a substrate processing apparatus. As shown in Figures 1 and 2, the coating/developing apparatus 2 includes a carrier block 4, a processing block 5, an interface block 6, and a control device 100 (control unit).

The carrier block 4 introduces the workpiece W into the coating/developing device 2 and removes the workpiece W from the coating/developing device 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, and then forms a coating of the processing liquid on the surface of the workpiece W. 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 applies a developer to the surface of the exposed workpiece W, and then rinses it away with a rinsing liquid to perform 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 pre-development heat treatment (PEB: Post Exposure Bake) and a post-development heat treatment (PB: Post Bake).

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 controls the coating/developing device 2 to perform the coating/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.

The control device 100 then controls the transport device A3 to transport the workpiece W from 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 surface of the workpiece W. The control device 100 then 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.

The control device 100 then 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. The control device 100 then 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 development processing for one workpiece W.

The specific configuration of the substrate processing apparatus is not limited to the configuration of the coating/developing apparatus 2 exemplified above. The substrate processing apparatus may be any type as long as it includes a liquid processing unit that forms a coating of the processing liquid after applying the processing liquid, and a control device that can control this.

(Liquid processing unit)
Next, an example of the liquid processing unit U1 of the processing module 12 will be described in detail with reference to Figures 3 and 4. The liquid processing unit U1 holds and rotates the workpiece W, and supplies a processing liquid to the surface Wa of the held workpiece W. After supplying the processing liquid, the liquid processing unit U1 rotates the workpiece W to form a coating of the processing liquid. As shown in Figure 3, the liquid processing unit U1 has, for example, a spinning and holding unit 20, a processing liquid supply unit 40, and a gas suction unit 50.

The rotating holding unit 20 holds the workpiece W at a predetermined position and rotates the workpiece W. The rotating holding unit 20 has, for example, a holding unit 22 and a rotation drive unit 24. The holding unit 22 supports the back surface of the workpiece W so that the front surface Wa of the workpiece W is horizontal. The holding unit 22 supports the back surface of the workpiece W with the front surface Wa of the workpiece W facing upward, and may hold the workpiece W (back surface) by, for example, vacuum suction or the like. The rotation drive unit 24 rotates the holding unit 22 around the vertical axis Ax by a power source such as an electric motor. This causes the workpiece W to rotate around the axis Ax. The holding unit 22 may hold the workpiece W so that the center of the workpiece W approximately coincides with the axis Ax.

The processing liquid supply unit 40 supplies processing liquid to the surface Wa of the workpiece W held in the holding unit 22. The processing liquid is a solution (resist liquid) for forming a resist film. The processing liquid supply unit 40 has, for example, a supply nozzle 42, a tank 44, a supply valve 46, a supply nozzle drive unit 48, and a supply pipeline 49.

The supply nozzle 42 ejects the processing liquid from above the surface Wa of the workpiece W toward the surface Wa of the workpiece W held in the holding portion 22. The supply nozzle 42 is connected to the tank 44 via a supply line 49. The tank 44 contains the processing liquid and supplies the processing liquid toward the supply nozzle 42. A supply valve 46 is provided in the supply line 49. The supply valve 46 is, for example, an air operation valve, and adjusts the opening degree in the supply line 49. By controlling the supply valve 46, it is possible to switch between a state in which the processing liquid is ejected from the supply nozzle 42 and a state in which the processing liquid is not ejected from the supply nozzle 42.

The supply nozzle drive unit 48 adjusts the position of the supply nozzle 42. The supply nozzle drive unit 48 moves the supply nozzle 42 along the surface Wa of the workpiece W, for example, by a power source such as a motor. The supply nozzle drive unit 48 may move the supply nozzle 42 along the radial direction of the workpiece W so as to pass through the center (axis Ax) of the workpiece W. In addition to moving the supply nozzle 42 horizontally, the supply nozzle drive unit 48 may further move the supply nozzle 42 along a direction perpendicular to the surface Wa of the workpiece W.

The gas suction unit 50 sucks gas (gas present in the vicinity) in the vicinity of the surface Wa of the workpiece W held in the holding unit 22. The gas suction unit 50 has, for example, a suction nozzle 52, a suction pump 54, a suction valve 56, a suction nozzle drive unit 58, and a suction pipeline 59.

The suction nozzle 52 is a nozzle that suctions gas. Specifically, the suction nozzle 52 includes an opening 52a, and suctions the gas from the opening 52a. The shape of the opening 52a (the outline of the opening edge) may be any shape, for example, a circle, an ellipse, a polygon, or a slit shape. FIG. 4(a) illustrates a case where the shape of the opening 52a is a circle. The width Da of the opening 52a is smaller than half the diameter of the workpiece W. The width Da of the opening 52a is defined as the maximum width of the opening 52a. When the shape of the opening 52a is a circle, the width Da of the opening 52a corresponds to the diameter of the opening 52a. For example, when the workpiece W is a circle, the width Da of the opening 52a (for example, the diameter) is smaller than the radius of the workpiece W. The width Da of the opening 52a may be 20% or less of the radius of the workpiece W, 5% or less of the radius of the workpiece W, or 1% or less of the radius of the workpiece W. In one example, the width Da of the opening 52a may be between 0.1 mm and 30 mm, between 0.5 mm and 10 mm, or between 1 mm and 5 mm.

The suction nozzle 52 (opening 52a) sucks gas in the vicinity (periphery) of the surface Wa of the workpiece W held by the holding part 22 from above the surface Wa of the workpiece W. For example, the suction nozzle 52 sucks gas present between a position about 50 mm above the surface Wa of the workpiece W and the surface Wa. The opening 52a is arranged so as to face the surface Wa of the workpiece W when sucking gas. The opening 52a is arranged so that a virtual line passing through the center of the opening 52a and along the suction direction of the gas from the opening 52a (direction perpendicular to the opening surface of the opening 52a) intersects with the surface Wa when sucking gas. In one example, the opening 52a is arranged so that the opening surface (virtual surface including the opening edge) of the opening 52a is approximately parallel to the surface Wa of the workpiece W held by the holding part 22, as shown in FIG. 4(b).

The suction nozzle 52 is positioned so that when gas is sucked in, the opening 52a and the surface Wa of the workpiece W are spaced apart by a predetermined distance Dd. The distance Dd is defined as the shortest distance between the opening 52a of the suction nozzle 52 and the surface Wa of the workpiece W when gas is sucked in. The distance Dd is set to such an extent that gas containing volatile components of the solvent contained in the resist liquid (processing liquid) is sucked in through the opening 52a. The distance Dd may be set to be greater than 3 mm and less than 30 mm. The distance Dd may be set to be greater than 4 mm and less than 20 mm, or greater than 5 mm and less than 10 mm. By setting the distance Dd as described above, gas in the vicinity of the surface Wa of the workpiece W is more reliably sucked in through the opening 52a.

Returning to FIG. 3, the suction nozzle 52 is connected to the suction pump 54 via the suction line 59. The suction pump 54 is a pump that generates a suction force to suck gas from the opening 52a. The suction valve 56 is provided in the suction line 59. The suction valve 56 is, for example, an air operation valve, and adjusts the opening degree in the suction line 59. The suction pump 54 continuously generates a suction force, and by controlling the suction valve 56, it is possible to switch between a state in which gas is sucked from the opening 52a of the suction nozzle 52 and a state in which gas is not sucked from the opening 52a.

The suction nozzle driving unit 58 adjusts the position of the suction nozzle 52. The suction nozzle driving unit 58 moves the suction nozzle 52 along the surface Wa of the workpiece W, for example, by a power source such as a motor. The suction nozzle driving unit 58 may move the suction nozzle 52 along the radial direction of the workpiece W so as to pass through the center (axis Ax) of the workpiece W. In addition to the horizontal movement, the suction nozzle driving unit 58 may further move the suction nozzle 52 along a direction perpendicular to the surface Wa of the workpiece W. In the example shown in FIG. 3, the supply nozzle 42 and the suction nozzle 52 are moved individually by different driving units, but the supply nozzle 42 and the suction nozzle 52 may be moved together by a single driving unit. For example, the supply nozzle 42 and the suction nozzle 52 are provided on a common arm (holder), and the liquid processing unit U1 may move the arm in a direction along the surface Wa of the workpiece W by a single driving unit.

(Control device)
As shown in FIG. 2, the control device 100 has a memory unit 102 and a control unit 104 as functional components. The memory unit 102 stores a program for operating each part of the coating/developing device 2 including the liquid processing unit U1. The memory unit 102 also stores various data (e.g., information related to an instruction signal for operating the liquid processing unit U1) and information from sensors and the like provided in each part. The memory unit 102 is, for example, a semiconductor memory, an optical recording disk, a magnetic recording disk, or a magneto-optical recording disk. The program may also be included in an external storage device separate from the memory unit 102, or in an intangible medium such as a propagated signal. The program may be installed in the memory unit 102 from these other media, and the program may be stored in the memory unit 102.

The control unit 104 controls the operation of each part of the coating/developing apparatus 2 based on the program read from the memory unit 102. The control unit 104 sequentially executes the following operations: while rotating the workpiece W with the rotating holder 20 so as to coat the surface Wa of the workpiece W with the treatment liquid, the treatment liquid is supplied to the surface Wa of the workpiece W by the treatment liquid supply unit 40; after the treatment liquid is supplied, the suction nozzle 52 is positioned so that the opening 52a faces the surface Wa of the workpiece W, and the gas in the vicinity of the surface Wa of the workpiece W is sucked in by the gas suction unit 50 through the opening 52a.

The control device 100 is composed of one or more control computers. For example, the control device 100 has 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 computer-readable storage medium, such as a hard disk. The storage medium stores a program for causing the control device 100 to execute the liquid 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 liquid processing unit U1 (the rotating holder 20, the processing liquid supply unit 40, and the gas suction unit 50) and the like 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 same.

(Substrate Processing Method)
Next, a liquid processing method executed in the liquid processing unit U1 will be described as an example of a substrate processing method. Fig. 6 is a flow chart showing an example of the liquid processing method for one workpiece W.

The control unit 104 of the control device 100 controls the liquid processing unit U1 to apply the processing liquid to the surface Wa of the workpiece W while the workpiece W is held by the rotating holder 20 (step S01). The control unit 104 supplies the processing liquid to the surface Wa of the workpiece W by the processing liquid supply unit 40 while rotating the workpiece W by the rotating holder 20. Details of the processing liquid application process in step S01 will be described later.

After the processing liquid is applied, the control unit 104 controls the liquid processing unit U1 to form a coating of the processing liquid on the surface Wa of the workpiece W (step S02). In the process of forming the coating of the processing liquid, the control unit 104 controls the gas suction unit 50 to suck gas in the vicinity of the surface Wa of the workpiece W from the opening 52a of the suction nozzle 52. Details of the coating formation process in step S02 will be described later. With the above, the liquid processing method for one workpiece W is completed. The workpiece W that has been subjected to the liquid processing is subjected to heat treatment by the heat treatment unit U2. As a result, the coating of the processing liquid is solidified and a resist film is formed on the surface Wa of the workpiece W.

Figure 7 is a flow chart showing an example of the application process of the treatment liquid in step S01. First, the control unit 104 causes the rotating holding unit 20 to start rotating the workpiece W to be treated while the workpiece W is placed on the holding unit 22 of the rotating holding unit 20 (step S11). In the subsequent processes, the rotation of the workpiece W continues until a process for stopping the rotation of the workpiece W is performed. After the rotation of the workpiece W starts, the control unit 104 may control the rotation drive unit 24 so that the workpiece W rotates at a predetermined rotational speed ω1.

Next, the control unit 104 causes the processing liquid supply unit 40 to start supplying the processing liquid to the surface Wa of the workpiece W (step S12). For example, the control unit 104 switches the supply valve 46 from a closed state to an open state while the supply nozzle 42 is positioned so that it overlaps with the central axis Ax (the rotation center of the workpiece W) about which the holding unit 22 rotates. As a result, while the workpiece W is rotating at a rotational speed ω1, the processing liquid begins to be ejected from the opening of the supply nozzle 42 toward the rotation center of the workpiece W.

Next, the control unit 104 waits until a predetermined supply time has elapsed since the supply of the treatment liquid from the supply nozzle 42 started (step S13). The supply time and the rotation speed ω1 are set to a degree that allows the treatment liquid to be sufficiently spread over the surface Wa of the workpiece W. The rotation speed ω1 is determined in advance, and may be, for example, 1000 rpm to 3500 rpm, 1500 rpm to 3200 rpm, or 2000 rpm to 3000 rpm.

Next, the control unit 104 stops the supply of the treatment liquid from the supply nozzle 42 to the treatment liquid supply unit 40 (step S14). For example, the control unit 104 switches the supply valve 46 from an open state to a closed state. This completes the application process of the treatment liquid to one workpiece W.

Figure 8 is a flow chart showing an example of the process for forming a coating of the processing liquid in step S02. After completion of the above-mentioned step S14, the control unit 104 first controls the rotation holding unit 20 to adjust the rotation speed of the workpiece W (step S21). For example, as shown in Figure 9, the control unit 104 controls the rotation drive unit 24 so that the rotation of the workpiece W is decelerated from rotation speed ω1 to rotation speed ω2. The rotation speed ω2 is set in advance.

Next, the control unit 104 controls the suction nozzle driving unit 58 to place the suction nozzle 52 at a predetermined position (step S22). By controlling the suction nozzle driving unit 58, the control unit 104 places the suction nozzle 52 at a predetermined position so that the opening 52a of the suction nozzle 52 faces the surface Wa. For example, the control unit 104 controls the suction nozzle driving unit 58 to place the suction nozzle 52, which is provided so that the opening surface of the opening 52a is approximately parallel to the surface Wa, so that the opening 52a faces the surface Wa (so that the opening 52a overlaps the surface Wa when viewed vertically from above).

The predetermined position where the suction nozzle 52 is placed (hereinafter referred to as the "nozzle placement position") is determined in advance by the operator or the operation program according to the position where the film thickness is adjusted by suction from the suction nozzle 52 (hereinafter referred to as the "film thickness adjustment position"). Details of film thickness adjustment will be described later. The nozzle placement position is set so that the opening 52a faces the film thickness adjustment position when the suction nozzle 52 is placed at that position. For example, when the opening surface of the opening 52a and the surface Wa are arranged approximately parallel to each other, the nozzle placement position is set so as to be located vertically above the film thickness adjustment position (so as to overlap with the film thickness adjustment position when viewed vertically from above). The nozzle placement position may be set so that the separation distance Dd (see FIG. 4(b)) between the opening 52a and the surface Wa is greater than 3 mm and less than 30 mm.

Next, the control unit 104 waits until the suction start timing arrives (step S23). The suction start timing is preset and is set after a predetermined time has elapsed after the supply of the processing liquid while rotating at the rotation speed ω1 has stopped. For example, as shown in FIG. 9, the suction start timing is set to time t2 after the supply of the processing liquid has stopped at time t1 and the rotation of the workpiece W has been adjusted to the rotation speed ω2.

Next (when the suction start timing arrives), the control unit 104 causes the gas suction unit 50 to start suctioning gas from the opening 52a of the suction nozzle 52 (step S24). The control unit 104, for example, switches the suction valve 56 from a closed state to an open state. This causes the suction force of the suction pump 54 to be generated from the opening 52a, and gas present in the vicinity of the surface Wa of the rotating workpiece W (in the vicinity of the film thickness adjustment position) begins to be sucked in. The amount of gas suctioned from the suction valve 56 (the flow rate of gas sucked in per unit time) is set, for example, to an extent that does not cause turbulence in the air flow caused by the rotation of the workpiece W in the vicinity of the surface Wa of the workpiece W.

Next, the control unit 104 waits until a predetermined suction time has elapsed since the start of gas suction (step S25). Next, the control unit 104 causes the gas suction unit 50 to stop suction from the opening 52a of the suction nozzle 52 (step S26). The control unit 104, for example, switches the suction valve 56 from an open state to a closed state. By executing the above steps S25 and S26, gas is suctioned near the film thickness adjustment position for the suction time while the workpiece W rotates at the rotation speed ω2. Since gas is suctioned while the workpiece W is rotating, gas is suctioned at a position along a circumference having a radius between the center of rotation (axis Ax) of the workpiece W and the film thickness adjustment position.

Next, the control unit 104 waits until a predetermined drying time has elapsed after the adjustment of the rotation speed in step S21 is completed (step S27). Next, the control unit 104 controls the rotation holding unit 20 to stop the rotation of the workpiece W (step S28). By executing the above steps S27 and S28, the control unit 104 causes the rotation holding unit 20 to continue rotating the workpiece W until the drying time has elapsed after the supply of the processing liquid is stopped.

The drying time and the above-mentioned rotation speed ω2 are set to a degree that allows the solvent contained in the treatment liquid applied to the surface Wa of the workpiece W to evaporate to a certain extent and a coating of the treatment liquid to be formed on the surface Wa. The drying time may be about 1 to 5 times the supply time for supplying the treatment liquid. The rotation speed ω2 of the workpiece W during the drying time (more specifically, the rotation speed ω2 of the workpiece W during the drying time after the adjustment of the rotation speed of the workpiece W is completed) may be smaller than the rotation speed ω1 of the workpiece W when the treatment liquid is supplied. For example, the rotation speed ω2 is set to about 1/5 to 2/3 of the rotation speed ω1. In one example, the rotation speed ω2 may be 200 rpm to 2300 rpm, 500 rpm to 2000 rpm, or 800 rpm to 1800 rpm.

Now, referring to FIG. 9, an example of the relationship between the suction of gas and drying for forming a coating will be described in detail. In FIG. 9, the time (period) during which drying for forming a coating of the treatment liquid is performed corresponds to the time from time t1 to time t4 (drying time Ta), and the time (period) during which gas is suctioned corresponds to the time from time t2 to time t3 (suction time Tb). The suction time Tb corresponds to a part of the drying time Ta. In the example shown in FIG. 9, the suction time Tb is set to be included in the first half of the drying time Ta. In other words, both the time t2 indicating the start time of the suction time Tb and the time t3 indicating the end time of the suction time Tb may be set to be included in the first half of the drying time Ta. In this case, the control unit 104 controls the gas suction unit 50 to suction gas near the film thickness adjustment position from the opening 52a during the first half of the drying time Ta.

This completes the coating formation process for one workpiece W. The procedure of the liquid processing method including the coating process and coating formation process described above is one example, and can be modified as appropriate. For example, some of the steps (processes) described above may be omitted, or each step may be performed in a different order. In addition, any two or more of the steps described above may be combined, or some of the steps may be modified or deleted. Alternatively, other steps may be performed in addition to the steps described above.

In the above example, gas suction is started after the rotation of the workpiece W is adjusted to the rotation speed ω2, but the control unit 104 may cause the gas suction unit 50 to start suctioning gas while the rotation of the workpiece W is being adjusted from the rotation speed ω1 to the rotation speed ω2. The control unit 104 may cause the gas suction unit 50 to start suctioning gas in the first half of the drying time Ta, and cause the gas suction unit 50 to finish suctioning gas in the second half of the drying time Ta. The control unit 104 may cause the gas suction unit 50 to perform suctioning gas in the second half of the drying time Ta.

In the above example, deceleration to the rotational speed ω2 is started after the supply of the treatment liquid is stopped, but the control unit 104 may cause the treatment liquid supply unit 40 to stop the supply of treatment liquid to the surface Wa of the workpiece W while the rotation of the workpiece W is being decelerated from the rotational speed ω1 to the rotational speed ω2. The control unit 104 may rotate the workpiece W at a rotational speed lower than the rotational speed ω2 during the drying time Ta (after the supply of the treatment liquid is stopped) before rotating the workpiece W at the rotational speed ω2. The time for rotating at this lower rotational speed may be shorter than the time for rotating at the rotational speed ω2. The control unit 104 may cause the gas suction unit 50 to start suctioning gas from the opening 52a after the time for rotating at this lower rotational speed has ended or while rotating at the lower rotational speed.

Next, referring to FIG. 10, the variation in film thickness accompanying gas suction will be described. FIG. 10 shows the measurement results of film thickness (film thickness distribution) when gas was not suctioned near the surface Wa of the workpiece W and when gas was suctioned from the opening 52a. In FIG. 10, the film thickness Ft0 shown by the dashed line shows the measurement result when the coating was formed without suctioning the gas present near the surface Wa of the workpiece W (when steps S22 to S26 shown in FIG. 8 were omitted). The film thickness Ft1 shown by the solid line shows the measurement result when gas present near the surface Wa of the workpiece W was suctioned from the suction nozzle 52 (when steps S21 to S28 shown in FIG. 8 were performed). In the measurement that obtained this film thickness Ft1, the suction nozzle 52 was positioned at the center of rotation so that the opening 52a of the suction nozzle 52 faces the center of rotation of the workpiece W, and gas was suctioned from the opening 52a.

The film thicknesses Ft0 and Ft1 are measured at multiple measurement points included in a line corresponding to the diameter passing through the center of the workpiece W. When the circular workpiece W is rotated and processed, it is considered that the film thickness distribution shows the same tendency along any line passing through the center of the workpiece W. Therefore, the tendency of the film thickness of the entire surface Wa can be estimated from the measurement results of multiple measurement positions along one line. By comparing the film thickness Ft0 and the film thickness Ft1, it can be seen that the film thickness Ft1 fluctuates (the film thickness is thicker overall) compared to the film thickness Ft0 at a measurement position near 0 mm (in the range of -25 mm to 25 mm). In other words, it can be seen that the film thickness fluctuates (is thicker) locally near the film thickness adjustment position to which the opening 52a is directed. In addition, since a gas flow toward the outer periphery of the workpiece W may occur above the surface Wa as the workpiece W rotates, the position where the film thickness fluctuates may shift outward from the position to which the opening 52a is directed (the film thickness adjustment position). In this case, the position to which the opening 52a is directed may be adjusted taking this shift into consideration in advance. At film thickness Ft1, a local decrease in film thickness occurs at the center of rotation of the workpiece W, which is facing the opening 52a of the suction nozzle 52 (located vertically below the opening 52a).

[Effects of the embodiment]
In the substrate processing method according to the embodiment described above, gas in the vicinity of the surface Wa of the workpiece W is sucked through the opening 52a having a width Da smaller than half the diameter of the workpiece W. As shown in FIG. 11, after the processing liquid is applied to the surface Wa of the workpiece W, a liquid film LF of the processing liquid is formed on the surface Wa. The solvent contained in the liquid film LF volatilizes into the space in the vicinity of the surface Wa (the upper surface of the liquid film LF), so that the solidification of the liquid film LF progresses and a coating of the processing liquid is formed. The faster the solidification time in the process of forming the coating, the thicker the coating becomes. In the above substrate processing method, in the process of forming the coating of the processing liquid, the gas in the vicinity of the surface Wa of the workpiece W is sucked through the opening 52a, so that the concentration of the solvent in the region V1, which is in the vicinity of the place where the gas is sucked, becomes lower than the concentration of the solvent in the other region V2 around the region V1. As a result, the evaporation of the solvent in the region V1 is promoted more than in the other region V2 around the region V1.

By promoting the evaporation of the solvent, the solidification of the liquid film LF progresses faster than in the other region V2, and as a result, the film thickness in region V1 can be varied. In this substrate processing method, since the width Da of the opening 52a of the suction nozzle 52 is small, this variation in film thickness can be caused in some locations on the surface of the workpiece W. This makes it possible to locally adjust the film thickness of the coating formed on the surface Wa of the workpiece W. Furthermore, by having such a configuration, it is also possible to change the location on the surface Wa of the workpiece W where the film thickness is adjusted by changing the position of the opening 52a of the suction nozzle 52. Therefore, for example, it is possible to adjust the film thickness of the coating at a desired location on the surface Wa of the workpiece W.

As a technique for adjusting a part of the film thickness within the surface of the workpiece W, for example, as in the technique described in the above-mentioned Patent Document 1, it is possible to discharge gas from a gas discharge nozzle to a predetermined position within the surface of the workpiece. FIG. 12(a) shows the measurement result of the film thickness when gas is discharged to a predetermined position on the surface of the workpiece. FIG. 12(b) shows the measurement result of the film thickness when gas is sucked from the opening 52a. In FIG. 12(a), the film thickness Fr0 shown by the dashed line shows the measurement result when gas is not discharged from the gas discharge nozzle, and the film thickness Fr1 shown by the solid line shows the measurement result when gas is discharged from the gas discharge nozzle. In the measurement in which the film thickness Fr1 was obtained, the gas discharge nozzle was placed at a position 27 mm away from the rotation center of the workpiece along the surface, and gas was discharged vertically downward from the gas discharge nozzle. The multiple measurement positions on the horizontal axis are set in the same manner as the multiple measurement positions in the measurement results shown in FIG. 10.

12(b), the film thickness Ft0 shown by the dashed line indicates the measurement result when the gas present near the surface Wa of the workpiece W was not sucked, and the film thickness Ft1 shown by the solid line indicates the measurement result when the gas present near the surface Wa of the workpiece W was sucked from the opening 52a. In the measurement that obtained the film thickness Ft1, the suction nozzle 52 (opening 52a) was placed at a position 27 mm away from the center of rotation of the workpiece W along the surface Wa, and gas was sucked vertically upward from the opening 52a. The multiple measurement positions on the horizontal axis are set in the same manner as the multiple measurement positions in the measurement results shown in FIG. 10. Comparing the results shown in FIG. 12(a) and the results shown in FIG. 12(b), when gas was ejected, not only the vicinity of the ejection position (the position 27 mm away) but the entire film thickness was thick. On the other hand, when gas was sucked, it can be seen that the film thickness near the suction position (the position 27 mm away) was thicker than other regions. In other words, it can be seen that the film thickness can be adjusted locally by sucking in the gas, compared to when the gas is ejected.

Figure 13(a) shows the measurement results of the film thickness distribution over the entire surface of the workpiece when gas is discharged during the process of forming a coating of the treatment liquid. Figure 13(b) shows the measurement results of the film thickness distribution over the entire surface Wa of the workpiece W when gas is suctioned during the process of forming a coating of the treatment liquid. The gray circular parts in the gray scale indicate the workpiece, and the color intensity corresponds to the thickness of the film. In the measurement result of Figure 13(a) (measurement result with gas discharge), there is unevenness in the thickness, indicating a large degree of variation from the average film thickness. In contrast, in the measurement result of Figure 13(b) (measurement result with gas suction), it can be seen that the occurrence of unevenness in the thickness is suppressed. This result is thought to be due to the fact that the airflow turbulence caused by suctioning the gas is smaller than the airflow turbulence caused by discharging the gas (airflow turbulence near the surface of the workpiece).

In the above embodiment, sucking gas from the opening 52a of the suction nozzle 52 includes sucking gas from the opening 52a with the suction nozzle 52 positioned so that the separation distance Dd between the opening 52a and the surface Wa of the workpiece W is greater than 3 mm and less than 30 mm. In the process of volatilization of the solvent contained in the liquid film LF (see FIG. 11) on the surface Wa, the concentration of the solvent contained in the space decreases as it moves upward from the upper surface of the liquid film LF. For example, by setting the separation distance Dd to less than 30 mm, the amount of solvent contained in the gas to be sucked can be increased, and the evaporation of the solvent due to the suction of the gas can be further promoted. On the other hand, by setting the separation distance Dd to more than 3 mm, it is possible to prevent the turbulence of the air flow in the space near the upper surface of the liquid film LF from increasing due to the suction of the gas. In the above method, by setting the separation distance Dd when aspirating the gas to be greater than 3 mm and less than 30 mm, it is possible to more reliably cause the film thickness to fluctuate as the gas is aspirated, and to suppress the occurrence of uneven film thickness due to turbulence in the air flow as the gas is aspirated.

In the above embodiment, the width Da of the opening 52a of the suction nozzle 52 is smaller than the separation distance Dd when gas is sucked through the opening 52a. The smaller the opening 52a, the smaller the airflow disturbance caused by suction. Therefore, the above method can further suppress the occurrence of unevenness in the film thickness due to the airflow disturbance caused by the suction of gas.

The substrate processing method according to the above embodiment further includes rotating the workpiece W until a predetermined time has elapsed since the supply of the processing liquid is stopped. Aspirating the gas from the opening 52a includes aspirating the gas from the opening 52a in the first half of the predetermined time. In the first half of the period in which the workpiece W is rotated after the supply of the processing liquid, the volatilization of the solvent in the processing liquid (in the liquid film LF) progresses more, and in the second half, the volatilization of the solvent slows down. Therefore, in the above method, aspirating the gas in the first half makes it possible to more reliably cause film thickness variations associated with the suction of the gas.

In the above embodiment, the rotational speed ω2 of the substrate when rotating the workpiece W for a given time is smaller than the rotational speed ω1 of the workpiece W when supplying the treatment liquid. In this case, gas is suctioned near the surface Wa of the workpiece W when rotating at a rotational speed ω2 that is smaller than the rotational speed ω1 of the workpiece W when supplying the treatment liquid. By slowing down the rotation of the workpiece W, the speed of the airflow that is generated in association with the rotation of the workpiece W and flows along the rotation direction in the vicinity of the surface Wa of the workpiece W slows down. Therefore, with the above method, more gas can be suctioned in a short suction time, making it possible to efficiently adjust the film thickness by suction.

[Modification]
The disclosure in this specification should be considered to be illustrative and not restrictive in all respects. Various omissions, substitutions, modifications, etc. may be made to the above examples without departing from the scope of the claims and the gist thereof.

(Variation 1)
In the above-mentioned coating formation process, control may be performed to reduce the rotation speed of the workpiece W when the gas is sucked. The control unit 104 may reduce the rotation speed of the workpiece W during the period during which the gas is sucked during the drying time for forming the coating. For example, as shown in FIG. 14, the control unit 104 controls the rotation holding unit 20 to adjust the rotation of the workpiece W from the rotation speed ω2 to the rotation speed ω3 at approximately the same timing as the timing (time t2) when the suction of gas from the opening 52a of the suction nozzle 52 is started. Then, the control unit 104 controls the rotation holding unit 20 to adjust the rotation of the workpiece W from the rotation speed ω3 to the rotation speed ω2 at approximately the same timing as the timing (time t3) when the suction of gas from the opening 52a is stopped.

As described above, the rotation speed ω3 of the work W when the gas is being sucked during the drying time is smaller than the rotation speed of the substrate during at least a portion of the period when the gas is not being sucked. In the example shown in FIG. 14, the rotation speed ω3 is smaller than the rotation speed ω2 of the work W when the gas is not being sucked during the drying time (more specifically, the drying time after the rotation speed is adjusted after the supply of the processing liquid is stopped). The rotation speed ω3 is preset to a value greater than 0, and may be 10 rpm to 1700 rpm smaller than the rotation speed ω2, 30 rpm to 1000 rpm smaller than the rotation speed ω2, or 50 rpm to 500 rpm smaller than the rotation speed ω2. In the first modification, the control unit 104 may also control the gas suction unit 50 to suck gas from the opening 52a during the first half of the drying time (the time from time t1 to time t4). In addition, the control unit 104 may cause the gas suction unit 50 to start suctioning gas from the opening 52a of the suction nozzle 52 after or during the adjustment of the rotation of the workpiece W from the rotation speed ω2 to the rotation speed ω3.

Figure 15(a) shows the measurement result of the film thickness when the rotation speed of the workpiece W was not reduced when the gas was sucked through the opening 52a. In Figure 15(a), the film thickness Ft0 shown by the dashed line shows the measurement result when the gas present near the surface Wa of the workpiece W was not sucked. The film thickness Ft1 shown by the solid line shows the measurement result when the rotation speed was not reduced when the gas was sucked, and the gas present near the surface Wa of the workpiece W was sucked through the opening 52a. Figure 15(b) shows the measurement result of the film thickness when the rotation speed of the workpiece W was reduced when the gas was sucked through the opening 52a. In Figure 15(b), the film thickness Ft0 shown by the dashed line shows the measurement result when the gas present near the surface Wa of the workpiece W was not sucked. The film thickness Ft2 shown by the solid line shows the measurement result (pertaining to the first modified example) when the rotation speed was reduced when the gas was sucked, and the gas present near the surface Wa of the workpiece W was sucked through the opening 52a.

In both measurements that gave the measurement results shown in Figures 15(a) and 15(b), the suction nozzle 52 was positioned 27 mm away from the center of rotation of the workpiece W, and gas was sucked vertically upward from the opening 52a. In Figures 15(a) and 15(b), the multiple measurement positions on the horizontal axis are set in the same way as the multiple measurement positions in the measurement results shown in Figure 10. From the measurement results shown in Figures 15(a) and 15(b), it can be seen that the film thickness fluctuates more (becomes thicker) near the film thickness adjustment position (the position 27 mm away) by reducing the rotation speed when sucking in gas, compared to when the rotation speed is not reduced when sucking in gas.

The substrate processing method according to the above-mentioned modified example 1 further includes rotating the workpiece W until a predetermined time has elapsed since the supply of the processing liquid was stopped. Suctioning the gas from the opening 52a of the suction nozzle 52 includes suctioning the gas from the opening 52a during a portion of the predetermined time. The rotation speed ω3 of the workpiece W when the gas is being sucked during the predetermined time may be smaller than the rotation speed ω2 of the workpiece W during at least a portion of the period during which the gas is not being sucked during the predetermined time. By slowing down the rotation of the workpiece W, the speed (flow velocity) of the air flow that is generated in the vicinity of the surface Wa of the workpiece W due to the rotation of the workpiece W and flows along the rotation direction is slowed down. Therefore, in the above-mentioned method, more gas can be sucked in during a short suction time, and efficient film thickness adjustment by suction is possible.

(Variation 2)
In the above-described coating formation process, the gas may be sucked while moving the opening 52a of the suction nozzle 52. The control unit 104 may control the gas suction unit 50 to suck the gas from the opening 52a while moving the opening 52a of the suction nozzle 52 back and forth along the surface Wa of the workpiece W. For example, the control unit 104 may cause the suction nozzle 52 to move back and forth by the suction nozzle drive unit 58 so that a position on the surface Wa of the workpiece W to which the opening 52a corresponds (a position where the openings 52a overlap when viewed vertically from above) moves back and forth along the radius of the workpiece W.

As shown in FIG. 16, the range in which the suction nozzle 52 is reciprocated (hereinafter referred to as the "sweep range ds") is smaller than the distance from the axis Ax to the periphery Wb (e.g., the radius of the workpiece W). The sweep range ds is set in advance, and is, for example, larger than the width Da of the opening 52a of the suction nozzle 52 (see FIG. 4(a)) and smaller than the radius of the workpiece W. In one example, the upper limit value of the sweep range ds may be less than twice the width Da, less than five times the width Da, or less than 20 times the width Da. When sucking gas from the opening 52a of the suction nozzle 52, the control unit 104 may cause the suction nozzle 52 to reciprocate using the suction nozzle drive unit 58 so that the number of times the opening 52a reciprocates in the sweep range ds is at least two or more. For example, the control unit 104 may cause the suction nozzle drive unit 58 to move the suction nozzle 52 back and forth at a speed similar to the movement speed when the suction nozzle 52 is moved to the placement position during suction.

Figure 17(a) shows the measurement result of the film thickness when the opening 52a is not moved back and forth when gas is sucked from the opening 52a. In Figure 17(a), the film thickness Ft0 shown by the dashed line shows the measurement result when gas present near the surface Wa of the workpiece W is not sucked. The film thickness Ft1 shown by the solid line shows the measurement result when the opening 52a is not moved back and forth and gas present near the surface Wa of the workpiece W is sucked from the opening 52a. Figure 17(b) shows the measurement result of the film thickness when the opening 52a is moved back and forth when gas is sucked from the opening 52a. In Figure 17(b), the film thickness Ft0 shown by the dashed line shows the measurement result when gas present near the surface Wa of the workpiece W is not sucked. The film thickness Ft3 shown by the solid line shows the measurement result (related to the modified example 2) when the opening 52a is moved back and forth and gas present near the surface Wa of the workpiece W is sucked from the opening 52a.

In the measurement that gave the measurement result in FIG. 17(a), gas was sucked vertically upward from the opening 52a with the suction nozzle 52 positioned on the axis Ax (a position overlapping the center of rotation of the workpiece W). In the measurement that gave the measurement result in FIG. 17(b), gas was sucked vertically upward from the opening 52a while the opening 52a was moved back and forth in a sweep range ds centered on the axis Ax (center of rotation) of the workpiece W. The multiple measurement positions on the horizontal axis in FIG. 17(a) and FIG. 17(b) are set in the same way as the multiple measurement positions in the measurement result shown in FIG. 10.

In the measurement results of film thickness Ft1 shown in FIG. 17(a), the film thickness is reduced at the measurement position of 0 mm (center of rotation). This phenomenon is thought to be due to the fact that when gas containing a solvent is sucked in from the opening 52a in region V1 shown in FIG. 11, the solvent flows in from the periphery of region V1, making it difficult for the solvent to evaporate near the center of region V1. On the other hand, in the measurement results of film thickness Ft3 shown in FIG. 17(b), there is no reduction in film thickness near the measurement position of 0 mm, as in the measurement results shown in FIG. 17(a).

In the substrate processing method according to the above-described modified example 2, sucking gas through the opening 52a of the suction nozzle 52 includes sucking gas through the opening 52a while moving the opening 52a back and forth in a direction along the surface Wa of the workpiece W. In this case, the position on the surface Wa of the workpiece W toward which the opening 52a of the suction nozzle 52 faces is not fixed, and it is possible to level out the tendency for film thickness fluctuations caused by the fixing of the position.

(Variation 3)
In the series of processes of the above-mentioned coating forming method, gas may be sucked at two coating adjustment positions. Returning to FIG. 16, the control unit 104 may control the liquid processing unit U1 to suck gas from the opening 52a as the film thickness adjustment position P1 and the film thickness adjustment position P2 as positions for adjusting the film thickness during the drying time in which the workpiece W is rotated to form a coating of the processing liquid. The film thickness adjustment position P1 is a position spaced apart by a distance r1 from the rotation center (axis Ax) of the workpiece W along the surface Wa, and the film thickness adjustment position P2 is a position spaced apart by a distance r2 from the rotation center (axis Ax) of the workpiece W along the surface Wa. In this case, the film thickness is adjusted by sucking gas near each of the film thickness adjustment positions P1 and P2. The distance r2 is greater than the distance r1, and the distance r1 may be zero (the film thickness adjustment position P1 may be the rotation center).

The control unit 104 may suck gas by the gas suction unit 50 for the two coating adjustment positions P1 and P2 in the order from the center of rotation of the workpiece W toward the periphery Wb of the workpiece W, or may suck gas by the gas suction unit 50 in the order from the periphery Wb of the workpiece W toward the center of rotation of the workpiece W. In the above-mentioned liquid processing method, the processing liquid is supplied in order from the center side to the outer periphery side of the workpiece W, and it is considered that the evaporation of the solvent of the processing liquid on the center side of the workpiece W proceeds faster than that on the outer periphery side. Since it is considered that the adjustment range of the film thickness is larger if the gas is sucked in as the evaporation of the solvent proceeds, the control unit 104 may suck gas by the gas suction unit 50 for the two coating adjustment positions in the order of the film thickness adjustment position P1 and the film thickness adjustment position P2.

More specifically, the control unit 104 first performs a first suction process in which gas in the vicinity of the film thickness adjustment position P1 (present in the vicinity) is sucked by the gas suction unit 50. In the first suction process, the control unit 104 causes the gas suction unit 50 to suck gas from the opening 52a while the opening 52a is directed toward the film thickness adjustment position P1, which is separated from the rotation center of the workpiece W by a distance r1 (first distance) along the surface Wa. The control unit 104, for example, positions the suction nozzle 52 by the suction nozzle drive unit 58 so that a virtual line passing through the center of the opening 52a and running along a direction perpendicular to the opening surface of the opening 52a intersects with the film thickness adjustment position P1. When the suction nozzle 52 is provided so that the opening surface of the opening 52a and the surface Wa are approximately parallel to each other, the control unit 104 positions the suction nozzle 52 by the suction nozzle drive unit 58 in the first suction process so that the nozzle position of the suction nozzle 52 is located vertically above the film thickness adjustment position P1.

After performing the first suction process, the control unit 104 performs a second suction process in which the gas in the vicinity of the film thickness adjustment position P2 (present in the vicinity) is sucked into the gas suction unit 50. In the second suction process, the control unit 104 causes the gas suction unit 50 to suck gas from the opening 52a while the opening 52a is directed toward the film thickness adjustment position P2, which is a distance r2 (second distance) away from the rotation center of the workpiece W along the surface Wa. The control unit 104, for example, positions the suction nozzle 52 by the suction nozzle drive unit 58 so that a virtual line passing through the center of the opening 52a and running along a direction perpendicular to the opening surface of the opening 52a intersects with the film thickness adjustment position P2. When the suction nozzle 52 is provided so that the opening surface of the opening 52a and the surface Wa are approximately parallel to each other, the control unit 104 positions the suction nozzle 52 by the suction nozzle drive unit 58 in the second suction process so that the nozzle position of the suction nozzle 52 is located vertically above the film thickness adjustment position P2.

In the coating formation method according to this modified example 3, the control unit 104 may cause the gas suction unit 50 to suck gas for at least one of the two film thickness adjustment positions P1, P2 while moving the opening 52a back and forth within the sweep range ds, as in modified example 2. The control unit 104 may cause the gas suction unit 50 to suck gas so that the time for sucking gas (suction time) differs for the two film thickness adjustment positions P1, P2. The control unit 104 may cause the gas suction unit 50 to suck gas from the opening 52a for three or more film thickness adjustment positions.

Figure 18(a) shows the measurement results of the film thickness when gas is sucked in from the periphery Wb of the workpiece W toward the rotation center of the workpiece W for two film thickness adjustment positions P1 and P2. In Figure 18(a), the film thickness Ft0 shown by the dashed line shows the measurement result when gas present in the vicinity of the surface Wa of the workpiece W is not sucked in. The film thickness Ft4 shown by the solid line shows the measurement result when gas present in the vicinity of the surface Wa is sucked in from the opening 52a in the order of the film thickness adjustment position P2 and the film thickness adjustment position P1. Figure 18(b) shows the measurement results of the film thickness when gas is sucked in from the rotation center of the workpiece W toward the periphery Wb of the workpiece W for two film thickness adjustment positions P1 and P2. In Figure 18(b), the film thickness Ft0 shown by the dashed line shows the measurement result when gas present in the vicinity of the surface Wa of the workpiece W is not sucked in. The film thickness Ft5 shown by the solid line indicates the measurement result when gas present near the surface Wa is sucked through the opening 52a in the order of film thickness adjustment position P1 and film thickness adjustment position P2.

18(a) and 18(b), in both cases, the film thickness adjustment position P1 is set at a distance r1 from the center of rotation of 0 mm, and the film thickness adjustment position P2 is set at a distance r2 from the center of rotation of 75 mm. In FIGS. 18(a) and 18(b), the multiple measurement positions on the horizontal axis are set in the same way as the multiple measurement positions in the measurement results shown in FIG. 10. From the measurement results in FIG. 18(a), it can be seen that the degree of film thickness fluctuation is small near the second film thickness adjustment position P1. It is considered that the solidification of the liquid film LF of the processing liquid (volatilization of the solvent) proceeds in sequence from the center side to the outer periphery side of the workpiece W. Therefore, if the center side is performed later, the progress of the solvent volatilization has already slowed down, and as a result, it is considered that the film thickness fluctuation is small. On the other hand, from the measurement results in FIG. 18(b), it can be seen that at both of the two film thickness adjustment positions P1 and P2, the film thickness fluctuation due to the suction of gas is larger than the measurement results in FIG. 18(a).

In the substrate processing method according to the above-mentioned modified example 3, sucking gas from the opening 52a of the suction nozzle 52 includes performing a first suction process of sucking gas from the opening 52a directed toward a position separated by a first distance (distance r1) from the center of rotation of the workpiece W along the surface Wa of the workpiece W, and performing a second suction process after the first suction process of sucking gas from the opening 52a directed toward a position separated by a second distance (distance r2) greater than the first distance from the center of rotation of the workpiece W along the surface Wa of the workpiece W. It is considered that the volatilization of the solvent of the processing liquid proceeds faster on the central side of the workpiece W than on the peripheral side of the workpiece W. In the above-mentioned method, gas is sucked in sequentially from the central side to the peripheral side of the workpiece W, so that the film thickness can be adjusted more reliably when adjusting the film thickness at at least two points.

(Other Modifications)
In the above-mentioned embodiment and modified examples 1 to 3, the liquid processing for forming a coating of resist liquid is exemplified, but the type of processing liquid used in the liquid processing to which the technology according to the present disclosure is applied may be a solution other than resist liquid. For example, in the liquid processing unit U1 that forms the lower layer film of the processing module 11, the film thickness may be locally adjusted by suction of gas from the gas suction part 50. In the liquid processing unit U1 that forms the upper layer film of the processing module 13, the film thickness may be locally adjusted by suction of gas from the gas suction part 50.

1...substrate processing system, 2...coating and developing apparatus, W...workpiece, Wa...surface, U1...liquid processing unit, 20...rotating holder, 40...processing liquid supply section, 50...gas suction section, 52...suction nozzle, 52a...opening, Da...width, Dd...distance, 100...control device, ω1, ω2, ω3...rotational speed, r1, r2...distance.

Claims (10)

supplying a treatment liquid to a surface of the substrate while rotating the substrate so as to coat the treatment liquid on the surface of the substrate to form a coating ;
after supplying the processing liquid, a nozzle including an opening having a width smaller than half the diameter of the substrate is disposed so that the opening faces the surface of the substrate, and while rotating the substrate, gas in the vicinity of the surface of the substrate is sucked through the opening ;
sucking the gas through the opening includes sucking the gas through the opening while reciprocating the opening in a direction along the surface of the substrate;
one end of a range in which the nozzle is reciprocated when the opening is reciprocated is set at a rotation center of the substrate,
The range is greater than a width of the opening and less than a radius of the substrate . The substrate processing method of claim 1, wherein sucking the gas through the opening includes sucking the gas through the opening with the nozzle positioned such that the distance between the opening and the surface of the substrate is greater than 3 mm and less than 30 mm. The substrate processing method according to claim 2, wherein the width of the opening is smaller than the separation distance when the gas is sucked through the opening. The method further includes rotating the substrate until a predetermined time has elapsed since the supply of the processing liquid is stopped,
4. The substrate processing method according to claim 1, wherein sucking the gas through the opening includes sucking the gas through the opening in a first half of the predetermined time period. The substrate processing method according to claim 4, wherein the rotation speed of the substrate when rotating the substrate during the predetermined time is smaller than the rotation speed of the substrate when the processing liquid is supplied. The method further includes rotating the substrate until a predetermined time has elapsed since the supply of the processing liquid is stopped,
Suctioning the gas through the opening includes sucking the gas through the opening during a portion of the predetermined time period,
A substrate processing method according to any one of claims 1 to 3, wherein a rotation speed of the substrate when the gas is being sucked in during the specified time is lower than a rotation speed of the substrate during at least a portion of a period when the gas is not being sucked in during the specified time. 7. The substrate processing method according to claim 1, wherein the nozzle is provided with a single opening for sucking in the gas. Suctioning the gas through the opening includes:
performing a first suction process for sucking the gas through the opening that faces a position spaced a first distance along the surface of the substrate from a rotation center of the substrate;
The substrate processing method according to any one of claims 1 to 7, further comprising: performing a second suction process after the first suction process, in which the gas is sucked through the opening directed toward a position spaced a second distance along the surface of the substrate from a center of rotation of the substrate by a second distance greater than the first distance. 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 8. a liquid processing unit including a rotary holder that holds and rotates a substrate, a processing liquid supplying unit that supplies a processing liquid for forming a coating on a surface of the substrate held by the rotary holder, and a gas suction unit that includes a nozzle having an opening with a width smaller than half the diameter of the substrate and a drive unit that adjusts the position of the nozzle and suctions a gas through the opening;
a control unit for controlling the liquid processing unit;
The control unit
supplying the processing liquid to the surface of the substrate by the processing liquid supply unit while rotating the substrate by the spin holder so as to coat the processing liquid on the surface of the substrate;
After the supply of the processing liquid, while rotating the substrate by the rotation holder with the nozzle disposed so that the opening faces the surface of the substrate, the gas in the vicinity of the surface of the substrate is sucked through the opening by the gas suction unit ;
the control unit causes the gas to be sucked through the opening while causing the opening to reciprocate in a direction along the surface of the substrate by the drive unit,
one end of a range in which the nozzle is reciprocated when the opening is reciprocated is set at a rotation center of the substrate,
The range is greater than a width of the opening and less than a radius of the substrate .

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