According to one embodiment, a substrate processing apparatus includes: a holding unit that holds a substrate; a driving unit that is provided in the holder and rotates the substrate together with the holder; a supply unit that supplies a processing liquid to a target surface of the substrate; a first cup provided to surround the substrate; a second cup provided to surround the first cup and having an inner wall surface having a property different from a property of an inner wall surface of the first cup; and a movement controller that moves the first cup and the second cup such that the processing liquid scattered from the substrate is received either on the inner wall surface of the first cup or on the inner wall surface of the second cup.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Japanese Patent Application No. 2022-048232 filed on Mar. 24, 2022 with the Japanese Patent Office, the disclosure of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

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

BACKGROUND

In the related art, a single-wafer type substrate processing apparatus has been known in which an etching processing or a cleaning processing is performed by supplying a processing liquid to a target surface of a substrate such a semiconductor wafer while rotating the substrate. The substrate processing apparatus includes a substrate holding unit, a rotation driving unit, a processing liquid supply unit, and a processing liquid recovering unit. The substrate holding unit holds an end portion of the substrate by a chuck pin provided on a table. The rotation driving unit rotates the substrate together with the substrate holding unit. The processing liquid supply unit ejects the processing liquid toward a target surface of the rotating substrate. The processing liquid recovering unit recovers the processing liquid that is scattered from the rotating substrate. Specifically, the scattered processing liquid is received by a cup provided to surround the rotation driving unit. The processing liquid flows in a downward direction along the inner wall surface of the cup, is recovered from a pipe provided in a bottom portion of the cup, and is reused.

Generally, the substrate processing is performed by switching a plurality of types of processing liquids. For this reason, with regard to the cup that receives the processing liquid as disclosed in, for example, Japanese Patent Laid-Open Publication No. 2009-110985, a technique is known in which the processing liquid scattered from the substrate can be received for each type of the processing liquid by moving the cup in an up and down direction thereby changing the height of the cup.

SUMMARY

When the substrate processing is performed by a plurality of types of processing liquids, the processing liquid may remain and stay on the inner wall surface of the cup due to, for example, the difference in the viscosities of the processing liquids. When a newly scattered processing liquid collides with the processing liquid remaining and staying on the inside of the cup, the processing liquid bursts (e.g., spatter) and becomes mist. The mist-like processing liquid may be scattered to the outside of the cup or may bounce back to the side of the substrate and adhere to the substrate. In particular, there is a problem that the mist of the processing liquid adhering to the substrate is dried leading to a product defect.

The present disclosure provides a substrate processing apparatus and a substrate processing method capable of suppressing the generation of the mist due to the collision of the processing liquid remaining and staying on the inner wall surface of the cup with a newly scattered processing liquid, thereby preventing the mist from adhering to the substrate.

A substrate processing apparatus according to the present disclosure includes: a holding unit that holds a substrate; a driving unit that is provided in the holding unit and rotates the substrate together with the holding unit; a supply unit that supplies a processing liquid to a target surface of the substrate; a first cup provided to surround the substrate; a second cup provided to surround the first cup and having an inner wall surface having a property different from a property of an inner wall surface of the first cup; and a movement control unit that moves the first cup and the second cup such that the processing liquid scattered from the substrate is received either on the inner wall surface of the first cup or on the inner wall surface of the second cup.

A substrate processing method according to the present disclosure includes: holding a substrate; rotating the substrate that is held; supplying a processing liquid to a target surface of the substrate; and moving a first cup provided to surround the substrate and a second cup provided to surround the first cup and including an inner wall surface having a property different from a property of an inner wall surface of the first cup such that the processing liquid scattered from the substrate is received either on the inner wall surface of the first cup or on the inner wall surface of the second cup.

According to the substrate processing apparatus and the substrate processing method according to the present disclosure, it is possible to suppress the generation of the mist due to the collision of the processing liquid remaining and staying on the inner wall surface of the cup with a newly scattered processing liquid, thereby preventing the mist from adhering to the substrate.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. As illustrated inFIG.1, a substrate processing apparatus1of the present embodiment is a single-wafer type substrate processing apparatus that performs an etching processing or a cleaning processing by supplying a processing liquid to a surface (hereinafter, also referred to as a “target surface”) of a substrate W such as a semiconductor wafer. The substrate processing apparatus1includes a holding unit11that holds the substrate W, a driving unit12that rotates the substrate W together with the holding unit11, supply units13that supply the processing liquid to the substrate W, a discharging unit14that discharges the processing liquid supplied to the substrate W, and a detecting unit15that detects the processing liquid that is scattered from the substrate W, is received by a cup C (to be described later), and bounces back. The substrate processing apparatus1includes a control unit8(to be described later), and is controlled by the control unit8.

The holding unit11includes a table T and a chuck pin P provided on an upper surface of the table T. The table T is, for example, a cylindrical stage. The chuck pin P is provided on the upper surface of the table T, and holds an edge of the substrate W.

The driving unit12is provided in the holding unit11. The driving unit12rotates the holding unit11and the substrate W held by the holding unit11around an axis perpendicular to the substrate W by, for example, a driving source such as a motor. The number of rotations of the substrate W is controlled by the control unit8.

The supply unit13is a nozzle provided to face a surface of the substrate W, and configured to eject the processing liquid toward the surface of the substrate W that is rotating by the driving unit12. A single supply unit13or a plurality of supply units13may be provided for each surface of the substrate W. In the following, descriptions will be made on a case where a single supply unit13is provided for each surface. The nozzle facing the surface (e.g., front surface) of both surfaces of the substrate W, which faces the same direction to the upper surface of the table T, is connected to a nozzle moving mechanism (not illustrated) so as to reciprocate between an ejection position facing a center of the front surface of the substrate W and a standby position radially outward of the substrate W from the ejection position. The nozzle facing the surface (e.g., back surface) of both surfaces of the substrate W that faces the upper surface of the table T is provided in a hollow portion (not illustrated) provided in a center of the table T. The nozzle is provided immovably so as not to be affected by the driving unit12and so as not to be rotated together with the table T. The control unit8controls the movement of the nozzle and the supply amount of the processing liquid.

Examples of the processing liquid of the present embodiment may include buffered hydrogen fluoride (BHF), deionized water (DIW), ozone water, and hydrogen fluoride (HF).

BHF is an aqueous solution obtained by mixing an aqueous solution of high-purity hydrofluoric acid and an aqueous solution of ammonium fluoride. BHF is used as an etching liquid for removing an oxide film formed on the surface of the substrate W, or metal impurities adhering to the surface (e.g., target surface) of the substrate W. Further, BHF has a relatively high viscosity.

DIW is pure water that contains almost no impurities. DIW is used as a rinse liquid for removing the etching liquid from the substrate W. Further, DIW has a relatively low viscosity.

Ozone water is an aqueous solution of ozone. Ozone water is used to form an oxide film on the surface of the substrate W where the oxide film is removed by BHF or HF so that Si is exposed. Further, ozone water has a relatively low viscosity.

HF is an aqueous solution of hydrofluoric acid. Similarly to BHF, HF is used as an etching liquid for removing an oxide film formed on the surface of the substrate W, or metal impurities adhering to the surface of the substrate W. Further, HF has a relatively low viscosity.

The discharging unit14is a container that receives the processing liquid scattered from the surface of the substrate W and discharges the received processing liquid. The discharging unit14is provided to surround the substrate W held by the driving unit12, and includes a cup C that receives the processing liquid scattered from the surface of the substrate W, and a pipe D that is provided in a bottom portion of the cup C and discharges the processing liquid that has traveled along an inner wall surface of the cup C.

The cup C includes a first cup C1and a second cup C2. The first cup C1and the second cup C2have a cylindrical shape including an opening that exposes the surface (e.g., front surface) of the substrate W, and both the first cup C1and second cup C2are provided to surround the substrate W. The second cup C2has a diameter larger than that of the first cup C1, and is provided to surround the first cup C1. Upper wall surfaces that form the openings of the first cup C1and the second cup C2are bent so as to be inclined radially inward. A tip of the portion that is bent (hereinafter, also referred to as a “bent portion”) is provided close to the holding unit11that holds the substrate W. As will be described later, a first pipe D1and a second pipe D2are provided in the first cup C1and the second cup C2, respectively, so as to discharge the processing liquid flowing along the inner wall surface of each of the first cup C1and the second cup C2. The processing liquid received by the inner wall surface of the second cup C2is prevented from accidently flowing into the first pipe D1by the upper surface of the bent portion of the first cup C1(see, e.g.,FIG.2).

The inner wall surface of the first cup C1includes, for example, countless fine grooves, and is hydrophilic. The inner wall surface of the second cup C2is, for example, coated with PFA, or contains PTFE, and is hydrophobic. In this manner, the properties of the inner wall surfaces of the first cup C1and second cup C2are different from each other.

The first cup C1includes a movement mechanism M1. The movement mechanism M1is controlled by the control unit8, and moves the first cup C1up and down. The second cup C2includes a movement mechanism M2. The movement mechanism M2is controlled by the control unit8, and moves the second cup C2up and down. As illustrated inFIG.1, when the first cup C1has been moved up, the processing liquid scattered from the substrate W is received by the inner wall surface of the first cup C1. Meanwhile, as illustrated inFIG.2, when the second cup C2has been moved up, and the first cup C1has been moved down, the inner wall surface of the second cup C2is exposed to the processing liquid scattered from the substrate W. Therefore, the processing liquid scattered from the substrate W is received by the inner wall surface of the second cup C2.

Hereinafter, descriptions will be made on the knowledge discovered by the present inventors regarding the relationship between the viscosity of the processing liquid and the property of the inner wall surface of the cup C.

When receiving a processing liquid having a high viscosity, the processing liquid is likely to remain and stay on the inner wall surface of the cup C as compared to the case of receiving a processing liquid having a low viscosity. For this reason, the high-viscosity processing liquid is likely to remain and stay in a raised state (e.g., a state where the contact angle of the droplet is large) on the inner wall surface of the cup C, compared to the low-viscosity processing liquid. When a processing liquid that is newly scattered from the substrate W collides with the processing liquid in a raised state, the processing liquid bursts due to the impact, and is fragmented into mist. The mist-like processing liquid bounces back to the side of the substrate W due to the impact of the collision and adheres to the target surface of the substrate W, which may cause a manufacturing defect.

The high-viscosity processing liquid is less likely to burst due to the relatively high viscosity. However, as described above, when the droplet remaining staying on the inner wall surface of the cup C in a raised state collides with the processing liquid that is newly scattered from the substrate W, the shape of the droplet collapses and the processing liquid bursts, and thus, becomes mist. At this time, when the inner wall surface of the cup C is hydrophilic, the processing liquid received on the inner wall surface remains so as to be spread over the inner wall surface of the cup C. That is, as compared to the case where the inner wall surface of the cup C is hydrophobic, the processing liquid received on and adhering to the inner wall surface is likely to have a flat shape (e.g., a state where the contact angle of the droplet is small). Even if the processing liquid adhering in such flat shape collides with the processing liquid that is newly scattered from the substrate W, the shape of the processing liquid is less likely to collapse, and thus, the processing liquid may be less likely to burst and become mist. That is, the possibility that the processing liquid becomes mist due to the impact of the collision, and bounces back to the side of the substrate W, is reduced. Therefore, the high-viscosity processing liquid may be received by the first cup C1, which is hydrophilic.

Meanwhile, even in a case where the low-viscosity processing liquid is received by the cup C having the hydrophilic inner wall surface, the low-viscosity processing liquid is likely to have a flat shape (e.g., a state where the contact angle of the droplet is small) on the inner wall surface of the cup C. However, the low-viscosity processing liquid is more likely to burst than the high-viscosity processing liquid due to the viscosity of the processing liquid itself. That is, when the processing liquid that is newly scattered from the substrate W collides with the low-viscosity processing liquid remaining on the inner wall surface of the cup C, the low-viscosity processing liquid is likely to burst due to the impact and become mist. At this time, when the inner wall surface of the cup C is hydrophobic, the low-viscosity processing liquid has a weak force to adhere to the inner wall surface of the cup C due to the relatively low viscosity, thereby forming a liquid droplet (e.g., a state where the contact angle of the droplet is large). That is, even though the amount is small, the processing liquid is less likely to remain on the inner wall surface of the cup C, and is likely to flow down along the inner wall surface of the cup C. For this reason, the possibility that the processing liquid remaining on the inner wall surface of the cup C collides with the processing liquid that is newly scattered from the substrate W, is suppressed, and thus, the processing liquid is less likely to become mist. Since the processing liquid is less likely to become mist, the possibility that the processing liquid bounces back to the side of the substrate W and adheres to the substrate W, is suppressed. Therefore, the low-viscosity processing liquid may be received by the second cup C2, which is hydrophobic.

As described above, the possibility that the processing liquid becomes mist may be suppressed by appropriately using the first cup C1having the hydrophilic inner wall surface and the second cup C2having the hydrophobic inner wall surface, according to the viscosity of the processing liquid, to receive the processing liquid. Since the processing liquid is less likely to become mist, the possibility that the processing liquid bounces back to the side of the substrate W and adheres to the substrate W, is suppressed. Determination on which property of the inner wall surface of the cup C is suitable for receiving which processing liquid, may be made by measuring the generated amount of mist through experiments in advance. In the present embodiment, the first cup C1having the hydrophilic inner wall surface is used to receive the processing liquid such as BHF, and the second cup C2having the hydrophobic inner wall surface is used to receive the processing liquid such as DIW, ozone water, and HF.

The pipe D includes a first pipe D1provided in the bottom surface of the first cup C1and a second pipe D2provided in the bottom surface of the second cup C2outside the first cup C1. The first pipe D1discharges (drains) the processing liquid that has traveled along the inner wall surface of the first cup C1. The second pipe D2discharges (drains) the processing liquid that has traveled along the inner wall surface of the second cup C2. Specifically, the first pipe D1and the second pipe D2are each connected to a gas-liquid separating device (not illustrated). The processing liquid that has traveled along the inner wall surface of the cup C is sent to a recovery tank of the processing liquid or a drainage facility of the plant by the gas-liquid separating device, and discharged. Further, the gas-liquid separating device may change the liquid sending destination according to the type of the processing liquid, and thus, the processing liquid may be discharged for each type. An exhaust gas may be sent to an exhaust facility of the plant by the gas-liquid separating device, and discharged.

The detecting unit15is, for example, a sensor such as a photoelectric sensor. In the following, the detecting unit15will be described as a reflective photoelectric sensor in which a light projecting unit and a light receiving unit are integrated. The detecting unit15is provided at a position that is above the cup C and does not interfere with the operation of moving the cup C up and down. Further, the detecting unit15is provided such that an optical axis thereof is parallel with the surface of the substrate W. The height of the optical axis of the detecting unit15is, for example, slightly higher than the upper end of the cup C that has been moved up. The detecting unit15detects the droplet (hereinafter, also referred to as “mist”) that is scattered from the substrate W, is received on the inner wall surface of the cup C, and bounces back from the inner wall surface of the cup C to the side of the substrate W. Therefore, the detecting unit15detects the droplet (mist) of the processing liquid bouncing back to the height that reaches the optical axis. When the detecting unit15detects a predetermined amount or more of the droplet of the processing liquid, the control unit8controls the driving unit12to reduce the number of rotations of the substrate W and controls the supply unit13to decrease the supply amount of the processing liquid.

The control unit8is, for example, constituted by a dedicated electronic circuit or a computer that is operated by a predetermined program, and controls each component of the substrate processing apparatus1. As illustrated inFIG.3, the control unit8includes a holding control unit81, a driving control unit82, a supply control unit83, a movement control unit84, a storage unit85, a setting unit86, and an input/output control unit87.

The holding control unit81controls the holding unit11to hold the substrate W. The driving control unit82controls the driving unit12to rotate or stop the substrate W. Further, the driving control unit82controls the driving unit12to change the number of rotations of the substrate W. For example, when the detecting unit15detects a predetermined amount or more of the droplet of the processing liquid, the number of rotations of the substrate W is reduced.

The supply control unit83controls the supply unit13to move the nozzle, and to supply the processing liquid or stop the supply of the processing liquid as well. Further, the supply control unit83controls the supply unit13to change the supply amount of the processing liquid. For example, when the detecting unit15detects a predetermined amount or more of the droplet of the processing liquid, the supply control unit13reduces the supply amount of the processing liquid.

The movement control unit84controls the first cup C1and the second cup C2provided in the discharging unit14. Specifically, the movement control unit84controls the movement mechanism M1provided in the first cup C1and the movement mechanism M2provided in the second cup C2to move the first cup C1and the second cup. For example, by moving the first cup C1up and down in a state where the first cup C1and second cup C2are raised, it is possible to select whether to receive the processing liquid scattered from the substrate W on the inner wall surface of the first cup C1or on the inner wall surface of the second cup C2. That is, the movement control unit84moves the first cup C1and the second cup C2such that the processing liquid scattered from the substrate W is received either on the inner wall surface of the first cup C1or on the inner wall surface of the second cup C2. Therefore, it is possible to select the cup C that is less likely to generate mist according to the type of the processing liquid. Further, the processing liquid may be discharged for each type by the pipe D provided in the bottom portion of the selected cup C.

The storage unit85is a recording medium such as an HDD or an SSD. The storage unit85stores data and a program necessary for the operation of a system in advance, and stores data necessary for the operation of the system as well. The setting unit86is a processing unit that sets information in the storage unit85according to the input. The input/output control unit87is an interface that controls conversion of signals or input/output between each of the components that are control targets.

The control unit8is connected to an input device91and an output device92. The input device91is an input unit such as a switch, a touch panel, a keyboard, or a mouse for operating the substrate processing apparatus1via the control unit8by an operator. The operator may input various information set in the storage unit85via the input device91. The output device92is an output unit such as a display, a lamp, or a meter that makes information visible to the operator to check the status of the apparatus. For example, the output device92may display an input screen for the information from the input device91.

The operation of the substrate processing apparatus1will be described with reference to a flowchart inFIG.4. It is assumed that the substrate W is held by the chuck pin P provided on the table T of the holding unit11. Further, as illustrated inFIG.1, the first cup C1and second cup C2are moved up by the movement mechanism M1and movement mechanism M2. That is, the processing liquid scattered from the substrate W is received on the inner wall surface of the first cup C1. This premise is implemented by first lowering the first cup C1and second cup C2to transfer the substrate W to the substrate processing apparatus1, and subsequently, holding the substrate W by the holding unit11, and then, raising the first cup C1and second cup C2.

First, the driving control unit82controls the driving unit12to rotate the substrate W at a predetermined number of rotations (step S01). Next, the supply control unit83controls the supply unit13to supply a predetermined amount of BHF to the target surface of the substrate W, and causes the BHF scattered from the substrate W to be received by the first cup C1, which is hydrophilic (step S02). The BHF received by the first cup C1having the hydrophilic inner wall surface is drained from the first pipe D1. At this time, the BHF having a relatively high viscosity remains so as to be spread over the inner wall surface of the first cup C1, so that the BHF is likely to have a flat shape (e.g., a state where the contact angle of the droplet is small). Therefore, the generation of mist and the bounce back to the side of the substrate W due to the collision with the BHF that is newly scattered, are suppressed. Therefore, the mist may be suppressed from adhering to the target surface of the substrate W.

When the substrate W is etched by BHF for a predetermined time, the supply control unit83controls the supply unit13to stop the supply of BHF (step S03). Continuously, as illustrated inFIG.2, the movement control unit84controls the discharging unit14to move the first cup C1down to expose the second cup C2that is being moved up in advance (step S04). When the second cup C2is exposed, the supply control unit83controls the supply unit13to switch the supply of the processing liquid from BHF to DIW and supply a predetermined amount of DIW to the surface of the substrate W in order to remove BHF from the substrate W, and causes the DIW to be received by the second cup C2having the hydrophobic inner wall surface (step S05). The DIW received by the second cup C2travels downward along the inner wall surface of the second cup C2, and is drained from the second pipe D2. At this time, the DIW having a relatively low viscosity has a weak force to adhere to the inner wall surface of the second cup C2, which is hydrophobic, due to the relatively low viscosity, thereby forming a liquid droplet (e.g., a state where the contact angle of the droplet is large). That is, since the DIW flows sequentially without remaining on the inner wall surface of the second cup C2, the possibility of the collision with the DIW that is newly scattered, is suppressed. Therefore, the generation of mist and the bounce back to the side of the substrate W are suppressed, so that the mist may be suppressed from adhering to the target surface of the substrate W.

When the substrate W is rinsed by DIW for a predetermined time, the supply control unit83controls the supply unit13to stop the supply of DIW. The movement control unit84maintains the state where the first cup C1is lowered and the second cup C2is raised. Next, the supply control unit83controls the supply unit13to switch the supply of the processing liquid from DIW to ozone water and supply a predetermined amount of ozone water to the surface of the substrate W in order to form an oxide film on the target surface of the substrate W, and causes the ozone water to be received by the second cup C2having the hydrophobic inner wall surface (step S06). The ozone water received by the second cup C2travels downward along the inner wall surface of the second cup C2, and is drained from the second pipe D2. At this time, the ozone water having a relatively low viscosity has a weak force to adhere to the inner wall surface of the second cup C2, which is hydrophobic, due to the relatively low viscosity, thereby forming a liquid droplet (e.g., a state where the contact angle of the droplet is large). That is, since the ozone water flows sequentially without remaining on the inner wall surface of the second cup C2, the possibility of the collision with the ozone water that is newly scattered, is suppressed. Therefore, the generation of mist and the bounce back to the side of the substrate W are suppressed, so that the mist may be suppressed from adhering to the target surface of the substrate W.

When the formation of the oxide film on the substrate W by ozone water is performed for a predetermined time, the supply control unit83controls the supply unit13to stop the supply of ozone water. The movement control unit84maintains the state where the first cup C1is lowered and the second cup C2is raised. Next, the supply control unit83controls the supply unit13to switch the supply of the processing liquid from ozone water to HF and supply a predetermined amount of HF to the target surface of the substrate W in order to remove the oxide film from the substrate W, and causes the HF to be received by the second cup C2having the hydrophobic inner wall surface (step S07). The HF received by the second cup C2travels downward along the inner wall surface of the second cup C2, and is drained from the second pipe D2. At this time, the HF having a relatively low viscosity has a weak force to adhere to the inner wall surface of the second cup C2, which is hydrophobic, due to the relatively low viscosity, thereby forming a liquid droplet (e.g., a state where the contact angle of the droplet is large). That is, since the HF flows sequentially without remaining on the inner wall surface of the second cup C2, the possibility of the collision with the HF that is newly scattered, is suppressed. Therefore, the generation of mist and the bounce back to the side of the substrate W are suppressed, so that the mist may be suppressed from adhering to the target surface of the substrate W.

When the substrate W is etched by HF for a predetermined time, the supply control unit83controls the supply unit13to stop the supply of HF. The movement control unit84maintains the state where the first cup C1is lowered and the second cup C2is raised. Next, the supply control unit83controls the supply unit13to switch the supply of the processing liquid from HF to ozone water and supply a predetermined amount of ozone water to the target surface of the substrate W in order to form an oxide film on the substrate W, and causes the ozone water to be received by the second cup C2having the hydrophobic inner wall surface (step S08). The ozone water received by the second cup C2travels downward along the inner wall surface of the second cup C2, and is drained from the second pipe D2. At this time, the ozone water having a relatively low viscosity has a weak force to adhere to the inner wall surface of the second cup C2, which is hydrophobic, due to the relatively low viscosity, thereby forming a liquid droplet (e.g., a state where the contact angle of the droplet is large). That is, since the ozone water flows sequentially without remaining on the inner wall surface of the second cup C2, the possibility of the collision with the ozone water that is newly scattered, is suppressed. Therefore, the generation of mist and the bounce back to the side of the substrate W are suppressed, so that the mist may be suppressed from adhering to the target surface of the substrate W.

When the formation of the oxide film on the substrate W by ozone water is performed for a predetermined time, the supply control unit83controls the supply unit13to stop the supply of ozone water. The movement control unit84maintains the state where the first cup C1is lowered and the second cup C2is raised. Next, the supply control unit83controls the supply unit13to switch the supply of the processing liquid from ozone water to DIW and supply a predetermined amount of DIW to the target surface of the substrate W in order to remove HF from the substrate W, and causes the DIW to be received by the second cup C2having the hydrophobic inner wall surface (step S09). The DIW received by the second cup C2travels downward along the inner wall surface of the second cup C2, and is drained from the second pipe D2. At this time, the DIW having a relatively low viscosity has a weak force to adhere to the inner wall surface of the second cup C2, which is hydrophobic, due to the relatively low viscosity, thereby forming a liquid droplet (e.g., a state where the contact angle of the droplet is large). That is, since the DIW flows sequentially without remaining on the inner wall surface of the second cup C2, the possibility of the collision with the DIW that is newly scattered, is suppressed. Therefore, the generation of mist and the bounce back to the side of the substrate W are suppressed, so that the mist may be suppressed from adhering to the target surface of the substrate W.

When the substrate W is rinsed by DIW for a predetermined time, the supply control unit83controls the supply unit13to stop the supply of DIW (step S10). Finally, the driving control unit82controls the driving unit12to increase the number of rotations of the substrate W (step S11). Therefore, DIW is shaken off from the substrate W, and the substrate W is dried. The DIW shaken off is received by the inner wall surface of the second cup C2, and is drained from the second pipe D2. At this time, the DIW having a relatively low viscosity has a weak force to adhere to the inner wall surface of the second cup C2, which is hydrophobic, due to the relatively low viscosity, thereby forming a liquid droplet (e.g., a state where the contact angle of the droplet is large). That is, since the DIW flows sequentially without remaining on the inner wall surface of the second cup C2, the possibility of the collision with the DIW that is newly scattered, is suppressed. Therefore, the generation of mist and the bounce back to the side of the substrate W are suppressed, so that the mist may be suppressed from adhering to the target surface of the substrate W.

Further, in the processing of the substrate W in step S01to step S11described above, when the detecting unit15detects a predetermined amount or more of the droplet of the processing liquid, the driving control unit82may control the driving unit12to reduce the number of rotations of the substrate W, and the supply control unit83may control the supply unit13to decrease the supply amount of the processing liquid. Therefore, the momentum of the processing liquid received on the inner wall surface of the cup C is suppressed, and further, the amount of the processing liquid is decreased as well, and thus, even when the mist is not sufficiently suppressed when selecting the cup C having the inner wall surface suitable for the viscosity of the processing liquid, the generation of the mist and the bounce back to the side of the substrate W due to the collision with the processing liquid may be efficiently suppressed. Therefore, the mist is efficiently suppressed from adhering to the target surface of the substrate W.

The number of rotations of the substrate W may be reduced uniformly to a predetermined number of rotations, or may be gradually reduced until the detecting unit15no longer detects a predetermined amount or more of the droplet of the processing liquid. In this case, the number of rotations of the substrate W may be maintained at the time when the detecting unit15no longer detects a predetermined amount or more of the droplet of the processing liquid.

The supply amount of the processing liquid may be decreased uniformly to a predetermined supply amount, or may be gradually decreased until the detecting unit15no longer detects a predetermined amount or more of the droplet of the processing liquid. In this case, the supply amount of the processing liquid may be maintained at the time when the detecting unit15no longer detects a predetermined amount or more of the droplet of the processing liquid.

Further, the number of rotations of the substrate W that is held and the supply amount of the processing liquid at the time when the detecting unit15no longer detects a predetermined amount or more of the droplet of the processing liquid are stored in the storage unit85, and are used for the subsequent processing of the substrate W. In the subsequent processing of the substrate W, when the detecting unit15detects a predetermined amount of the droplet of the processing liquid again, the number of rotations of the substrate W or the supply amount of the processing liquid may be adjusted again, and the number of rotations of the substrate W or the supply amount of the processing liquid, which is adjusted, may be newly used.

(1) The substrate processing apparatus1according to the present embodiment includes: the holding unit11that holds the substrate W; the driving unit12that is provided in the holding unit11and rotates the substrate W together with the holding unit11; the supply unit13that supplies the processing liquid to the target surface of the substrate W to process the substrate W; the first cup C1provided to surround the substrate W; the second cup C2provided to surround the first cup C1and having the inner wall surface having the property different from the property of the inner wall surface of the first cup C1; and the movement control unit84that moves the first cup C1and the second cup C2such that the processing liquid scattered from the substrate W is received either on the inner wall surface of the first cup C1or on the inner wall surface of the second cup C2. Therefore, it is possible to select the cup C that includes the inner wall surface suitable for receiving the processing liquid according to the viscosity of the processing liquid. For example, for a high-viscosity processing liquid that is received on and remains on the inner wall surface of the cup C, the cup C capable of reducing the contact angle of the droplet on the inner wall surface may be selected, and for a low-viscosity processing liquid that is likely to burst and become mist when received on the cup C, the cup C on which the processing liquid is less likely to remain on the inner wall surface may be selected. Therefore, it is possible to suppress the possibility that the processing liquid remaining on the inner wall surface collides with the processing liquid that is newly scattered to generate mist, or to suppress the possibility of the collision with the processing liquid that is newly scattered by making the processing liquid not stay on the inner wall surface, thereby suppressing the generation of mist. In either case, the generation of mist may be suppressed, and thus, the mist may be suppressed from adhering to the target surface of the substrate W.

(2) The inner wall surface of the first cup C1of the present embodiment is hydrophilic, and the inner wall surface of the second cup C2is hydrophobic. Therefore, the processing liquid such as BHF having a relatively high viscosity is received by the inner wall surface of the first cup C1, which is hydrophilic. Therefore, the contact angle of the processing liquid on the inner wall surface is reduced, and thus, it is possible to suppress the possibility of the generation of mist due to the collision with the processing liquid that is newly scattered. Further, the processing liquid such as DIW, ozone water, or HF having a relatively low viscosity is received by the inner wall surface of the second cup C2, which is hydrophobic. Therefore, the contact angle of the processing liquid on the inner wall surface is increased, and thus, the processing liquid does not remain on the inner wall surface and it is possible to suppress the possibility of the collision with the processing liquid that is newly scattered. Therefore, the generation of mist may be suppressed. In this manner, in any cases of a high-viscosity processing liquid or a low-viscosity processing liquid, the generation of mist is suppressed, and thus, the mist may be suppressed from adhering to the target surface of the substrate W.

(3) The substrate processing apparatus1according to the present embodiment further includes the detecting unit15that detects the droplet of the processing liquid that is received either on the inner wall surface of the first cup C1or on the inner wall surface of the second cup C2, and bounces back toward the side of the substrate W. When the detecting unit15detects a predetermined amount or more of the droplet of the processing liquid, the driving unit12reduces the number of rotations of the substrate W, and the supply unit13decreases the amount of the processing liquid supplied to the substrate W. Therefore, the momentum of the processing liquid received on the inner wall surface of the cup C is suppressed, and further, the amount of the processing liquid is decreased as well, and thus, even when the mist is not sufficiently suppressed when selecting the cup C having the inner wall surface suitable for the viscosity of the processing liquid, the generation of the mist and the bounce back to the side of the substrate W due to the collision with the processing liquid may be efficiently suppressed. Therefore, the mist may be efficiently suppressed from adhering to the target surface of the substrate W.

(1) In the above embodiment, the first cup C1is hydrophilic and the second cup C2provided outside the first cup C1is hydrophobic, but the present disclosure is not limited thereto. The first cup C1may be hydrophobic and the second cup C2provided outside the first cup C1may be hydrophilic. In this case, similarly to the above embodiment, when the processing is first performed by using BHF, which is a high-viscosity processing liquid, and then, the processing is performed by using DIW, ozone water, or HF, which is a low-viscosity processing liquid, in the processing step using BHF, the first cup C1is moved down so that the second cup C2is exposed for the processing liquid that is scattered from the substrate W. Therefore, BHF, which has a relatively high viscosity, is received by the second cup C2that is provided outside and is hydrophilic. Therefore, the contact angle of the processing liquid on the inner wall surface is reduced, and thus, it is possible to suppress the possibility of the generation of mist due to the collision with the processing liquid that is newly scattered. Meanwhile, in the processing step using DIW, ozone water, or HF, the first cup C1is moved up, so that the first cup C1faces the processing liquid scattered from the substrate W. Therefore, DIW, ozone water, or HF, which has a relatively low viscosity, is received by the first cup C1, which is hydrophobic, and flows sequentially without remaining on the inner wall surface of the first cup C1. Therefore, since the processing liquid does not remain on the inner wall surface, it is possible to suppress the possibility of the collision with the processing liquid that is newly scattered. Thus, the generation of mist may be suppressed. In either case, the generation of mist may be suppressed, and thus, the mist may be suppressed from adhering to the target surface of the substrate W.

(2) When the detecting unit15of the above embodiment detects a predetermined amount or more of the droplet of the processing liquid, the driving control unit82controls the driving unit12to reduce the number of rotations of the substrate W, and the supply control unit83controls the supply unit13to decrease the supply amount of the processing liquid, but the present disclosure is not limited thereto. For example, the driving unit12reduces the number of rotations of the substrate W, but the supply unit13may not decrease the supply amount of the processing liquid. Further, the supply unit13decreases the supply amount of the processing liquid, but the driving unit12may not reduce the number of rotations of the substrate W. The detecting unit15may be omitted and the number of rotations of the substrate W or the supply amount of the processing liquid may not be controlled according to the detection of the detecting unit15.

(3) The detecting unit15of the above embodiment is the reflective photoelectric sensor in which a light projecting unit and a light receiving unit are integrated, but the present disclosure is not limited thereto. For example, a transmissive photoelectric sensor in which a light projecting unit and a light receiving unit are separate bodies, may be used. Further, the detecting unit15is not limited to a photoelectric sensor, but may be an infrared (IR) camera, a CCD camera, or a CMOS camera.

(4) The processing liquids of the above embodiment are BHF, DIW, ozone water, and HF, but the present disclosure is not limited thereto. For example, any appropriate processing liquids suitable for processing the substrate W, such as sulfuric acid or phosphoric acid, may be used. Further, the order of using the processing liquids of the above embodiment is an example, and the processing liquids may be used in an arbitrary order. For example, a low-viscosity processing liquid, a high-viscosity processing liquid, and a low-viscosity processing liquid may be used in this order. In this case, for the processing liquid scattered from the substrate W, each of the processing liquids may be received by facing the inner wall surface of the second cup C2, which is hydrophobic, the inner wall surface of the first cup C1, which is hydrophilic, and the inner wall surface of the second cup C2, which is hydrophobic, respectively.