JP7189993B2 - Substrate processing equipment - Google Patents

Description

An embodiment of the present invention relates to a substrate processing apparatus.

A freeze cleaning method has been proposed as a method for removing contaminants such as particles adhering to the surfaces of substrates such as imprint templates, photolithography masks, and semiconductor wafers.

In the freeze cleaning method, for example, when pure water is used as the cleaning liquid, first, pure water and cooling gas are supplied to the surface of the rotated substrate. Next, the supply of pure water is stopped and part of the supplied pure water is discharged to form a water film on the surface of the substrate. The water film is frozen by the cooling gas supplied to the substrate. When the water film freezes to form an ice film, contaminants such as particles are trapped in the ice film and separated from the surface of the substrate. Next, pure water is supplied to the ice film to melt the ice film, and contaminants are removed from the surface of the substrate together with the pure water. This improves the removal rate of contaminants.

Here, pure water has low conductivity. Therefore, static electricity is likely to occur when pure water is supplied to the surface of the rotated substrate. On the other hand, on the surface of the substrate, a conductive pattern, an element for insulating the conductive pattern, or the like may be formed. Therefore, the generated static electricity may cause dielectric breakdown or the like. In addition, chemical reactions caused by static electricity may damage the substrate surface and patterns.

Therefore, development of a substrate processing apparatus capable of suppressing the generation of static electricity and improving the removal rate of contaminants has been desired.

JP 2018-026436 A

The problem to be solved by the present invention is to provide a substrate processing apparatus capable of suppressing the generation of static electricity and improving the removal rate of contaminants.

A substrate processing apparatus according to an embodiment includes: a mounting table capable of rotating a substrate; a cooling unit capable of supplying a cooling gas to a space between the mounting table and the substrate; a first liquid supply unit capable of supplying a first liquid to the surface opposite to the substrate side; and a second liquid supply unit capable of supplying a second liquid having a higher conductivity than the first liquid to the surface of the substrate. a liquid supply unit; and a control unit that controls rotation of the substrate, supply of the cooling gas, supply of the first liquid, and supply of the second liquid. The control unit supplies the second liquid to the surface of the substrate by controlling the supply of the cooling gas, the supply of the first liquid, and the supply of the second liquid. a preliminary step of supplying the cooling gas to the space between the writing table and the substrate; and after the preliminary step, supplying the first liquid toward the surface of the substrate to form a liquid film. performing a film forming step, a supercooling step of bringing the liquid film on the surface of the substrate into a supercooled state, and a freezing step of freezing at least a portion of the liquid film on the surface of the substrate. do. After stopping the supply of the second liquid in the liquid film forming step, the control unit rotates the substrate at the number of revolutions in the preliminary step to rotate the second liquid supplied to the surface of the substrate. At least a portion of the second liquid is discharged, and after at least a portion of the second liquid is discharged, the rotation speed is set to a first rotation speed slower than the rotation speed of the preliminary step, and then directed toward the surface of the substrate. supplying the first liquid ;

According to an embodiment of the present invention, a substrate processing apparatus is provided that can suppress the generation of static electricity and improve the removal rate of contaminants.

1 is a schematic diagram for illustrating a substrate processing apparatus according to an embodiment; FIG. FIG. 3 is a schematic diagram for illustrating a controller of the substrate processing apparatus according to the embodiment; 4 is a timing chart for illustrating the action of the substrate processing apparatus; 4 is a graph for illustrating temperature changes of liquid supplied to a substrate in a freeze cleaning process; It is a flow chart in the case of performing a freeze washing process multiple times. FIG. 10 is a flow chart explaining the operation of the control unit when the freeze cleaning process is performed multiple times. FIG. It is a schematic diagram for illustrating the substrate processing apparatus which concerns on other embodiment. 9 is a timing chart for illustrating actions of a substrate processing apparatus according to another embodiment;

Hereinafter, embodiments will be illustrated with reference to the drawings. In addition, in each drawing, the same reference numerals are given to the same constituent elements, and detailed description thereof will be omitted as appropriate.
The substrate 100 exemplified below can be, for example, a semiconductor wafer, an imprint template, a photolithography mask, a plate-like body used for MEMS (Micro Electro Mechanical Systems), or the like.
Note that the surface of the substrate 100 may have an uneven portion as a pattern formed thereon, or may be a substrate (for example, a so-called bulk substrate) before the uneven portion is formed. However, the application of the substrate processing apparatus 1 is not limited to the illustrated substrate 100 .

Moreover, in the following, as an example, a case where the substrate 100 is a photolithography mask will be described. When the substrate 100 is a mask for photolithography, the planar shape of the substrate 100 can be substantially rectangular.

FIG. 1 is a schematic diagram for illustrating a substrate processing apparatus 1 according to this embodiment.
FIG. 2 is a schematic diagram for illustrating the controller 9 of the substrate processing apparatus 1 according to this embodiment.
As shown in FIG. 1, the substrate processing apparatus 1 includes a mounting section 2, a cooling section 3, a first liquid supply section 4, a second liquid supply section 5, a housing 6, a blower section 7, a control section 9, and a An exhaust section 11 is provided. Further, as shown in FIG. 2, the control section 9 is provided with a mechanism control section 9a, a setting section 9b, and a storage section 9c.

The mounting section 2 has a mounting table 2a, a rotating shaft 2b, and a driving section 2c.
The mounting table 2 a is rotatably provided inside the housing 6 . The mounting table 2a has a plate shape. A plurality of support portions 2a1 for supporting the substrate 100 are provided on one main surface of the mounting table 2a. When the substrate 100 is supported by the plurality of supporting portions 2a1, the front surface 100b of the substrate 100 (the surface on which the uneven portions are formed) faces away from the mounting table 2a.

Edges of the rear surface 100a of the substrate 100 are in contact with the plurality of supporting portions 2a1. A portion of the supporting portion 2a1 that contacts the edge of the back surface 100a of the substrate 100 can be a tapered surface or an inclined surface.

Further, a hole 2aa is provided in the central portion of the mounting table 2a so as to extend through the mounting table 2a in the thickness direction.

One end of the rotary shaft 2b is fitted into the hole 2aa of the mounting table 2a. The other end of the rotating shaft 2b is provided outside the housing 6. As shown in FIG. The rotating shaft 2b is connected to the driving portion 2c outside the housing 6. As shown in FIG.

The rotating shaft 2b has a cylindrical shape. A blowout portion 2b1 is provided at the end portion of the rotating shaft 2b on the mounting table 2a side. Blow-out portion 2b1 opens to a surface of mounting table 2a on which a plurality of support portions 2a1 are provided. The opening-side end of blowout portion 2b1 is connected to the inner wall of hole 2aa. The opening of the blowout part 2b1 faces the rear surface 100a of the substrate 100 mounted on the mounting table 2a.

The blowout portion 2b1 has a shape in which the cross-sectional area increases toward the mounting table 2a side (opening side). Therefore, the hole inside the blowout part 2b1 has a larger cross-sectional area toward the mounting table 2a side (opening side). In addition, although the case where the blowing part 2b1 is provided at the tip of the rotating shaft 2b is illustrated, the blowing part 2b1 can also be provided at the tip of a cooling nozzle 3d described later. Also, the hole 2aa of the mounting table 2a can be used as the blowout portion 2b1.

By providing the blowout portion 2b1, the discharged cooling gas 3a1 can be supplied to a wider area of the back surface 100a of the substrate 100. FIG. Also, the discharge speed of the cooling gas 3a1 can be reduced. Therefore, it is possible to prevent the substrate 100 from being partially cooled or the cooling rate of the substrate 100 from becoming too fast. As a result, it becomes easy to cause a supercooled state of the liquid 101 (corresponding to an example of the first liquid) to be described later.

A cooling nozzle 3d is attached to the end of the rotating shaft 2b opposite to the mounting table 2a side. A rotating shaft seal (not shown) is provided between the end of the rotating shaft 2b opposite to the mounting table 2a side and the cooling nozzle 3d. Therefore, the end of the rotating shaft 2b on the side opposite to the mounting table 2a side is sealed so as to be airtight.

The drive unit 2c is provided outside the housing 6. As shown in FIG. The driving portion 2c is connected to the rotating shaft 2b. The drive unit 2c can have a rotating device such as a motor. The rotational force of the driving portion 2c is transmitted to the mounting table 2a via the rotating shaft 2b. Therefore, the driving unit 2c can rotate the mounting table 2a and the substrate 100 mounted on the mounting table 2a.

Further, the drive unit 2c can change not only the start and stop of rotation, but also the number of rotations (rotational speed). The drive unit 2c can be provided with a control motor such as a servomotor, for example.

Cooling unit 3 supplies cooling gas 3a1 to the space between mounting table 2a and back surface 100a of substrate 100 . The cooling unit 3 has a coolant unit 3a, a filter 3b, a flow control unit 3c, and a cooling nozzle 3d. Coolant section 3 a , filter 3 b , and flow control section 3 c are provided outside housing 6 .

The coolant unit 3a stores the coolant and generates the coolant gas 3a1. The cooling liquid is obtained by liquefying the cooling gas 3a1. The cooling gas 3 a 1 is not particularly limited as long as it is a gas that does not readily react with the material of the substrate 100 . The cooling gas 3a1 can be, for example, an inert gas such as nitrogen gas, helium gas, or argon gas.

The cooling liquid unit 3a has a tank that stores the cooling liquid and a vaporization unit that vaporizes the cooling liquid contained in the tank. The tank is provided with a cooling device for maintaining the temperature of the coolant. The evaporator raises the temperature of the cooling liquid to generate cooling gas 3a1 from the cooling liquid. For example, the vaporization section can use the temperature of the outside air or heat with a heat medium. The temperature of the cooling gas 3a1 may be any temperature below the freezing point of the liquid 101, and may be -170° C., for example.

The coolant unit 3a evaporates the coolant stored in the tank to generate the coolant gas 3a1.
was exemplified, nitrogen gas or the like can be cooled by a chiller or the like to form the cooling gas 3a1. In this way, the coolant section can be simplified.

The filter 3b is connected to the cooling liquid section 3a via a pipe. The filter 3b prevents contaminants such as particles contained in the coolant from flowing out to the substrate 100 side.

The flow controller 3c is connected to the filter 3b via piping. The flow controller 3c controls the flow rate of the cooling gas 3a1. The flow controller 3c can be, for example, an MFC (Mass Flow Controller). Further, the flow control unit 3c may indirectly control the flow rate of the cooling gas 3a1 by controlling the supply pressure of the cooling gas 3a1. In this case, the flow control unit 3c can be, for example, an APC (Auto Pressure Controller).

The temperature of the cooling gas 3a1 generated from the cooling liquid in the cooling liquid section 3a is approximately a predetermined temperature. Therefore, the temperature of the substrate 100 and the temperature of the liquid 101 on the surface 100b of the substrate 100 can be controlled by controlling the flow rate of the cooling gas 3a1 by the flow control unit 3c. In this case, by controlling the flow rate of the cooling gas 3a1 with the flow control unit 3c, the supercooled state of the liquid 101 can be generated in the supercooling step described later.

The cooling nozzle 3d has a cylindrical shape. One end of the cooling nozzle 3d is connected to the flow controller 3c. The other end of the cooling nozzle 3d is provided inside the rotating shaft 2b. The other end of the cooling nozzle 3d is positioned near the end opposite to the mounting table 2a side (opening side) of the blowout portion 2b1.

The cooling nozzle 3d supplies the substrate 100 with the cooling gas 3a1 whose flow rate is controlled by the flow control unit 3c. Cooling gas 3a1 discharged from cooling nozzle 3d is directly supplied to rear surface 100a of substrate 100 via blowing portion 2b1.

The first liquid supply section 4 supplies the liquid 101 to the surface 100 b of the substrate 100 . As will be described later, the liquid 101 is preferably a liquid that hardly reacts with the material of the substrate 100 and that increases in volume when frozen. The liquid 101 is preferably, for example, water (for example, pure water, ultrapure water, etc.) or a liquid containing water as a main component.

The liquid containing water as a main component can be, for example, a mixture of water and alcohol, a mixture of water and an acid solution, a mixture of water and an alkali solution, or the like.
Since the surface tension can be lowered by using a mixture of water and alcohol, it becomes easy to supply the liquid 101 inside the fine irregularities formed on the surface 100 b of the substrate 100 .

A mixed solution of water and an acid solution can dissolve contaminants such as particles and resist residues adhering to the surface of the substrate 100 . For example, a mixture of water and sulfuric acid can dissolve contaminants such as resist and metal.
A mixed solution of water and an alkaline solution can lower the zeta potential, so that contaminants separated from the surface 100b of the substrate 100 can be prevented from reattaching to the surface 100b of the substrate 100.

However, if there are too many components other than water, it becomes difficult to utilize the physical force that accompanies the increase in volume, so there is a risk that the contaminant removal rate will decrease. Therefore, the concentration of components other than water is preferably 5 wt % or more and 30 wt % or less.

The first liquid supply section 4 has a liquid storage section 4a, a supply section 4b, a flow control section 4c, and a liquid nozzle 4d. The liquid storage section 4a, the supply section 4b, and the flow control section 4c are provided outside the housing 6. As shown in FIG.

The liquid storage portion 4a stores the liquid 101 described above. The liquid 101 is stored in the liquid storage portion 4a at a temperature higher than its freezing point. The liquid 101 is stored at room temperature (20° C.), for example.
The supply portion 4b is connected to the liquid storage portion 4a via a pipe. The supply unit 4b supplies the liquid 101 stored in the liquid storage unit 4a toward the liquid nozzle 4d. The supply unit 4b can be, for example, a pump that is resistant to the liquid 101, or the like. In addition, although the case where the supply part 4b was a pump was illustrated, the supply part 4b is not necessarily limited to a pump. For example, the supply unit 4b may supply gas to the inside of the liquid storage unit 4a to pump the liquid 101 stored in the liquid storage unit 4a.

The flow control unit 4c is connected to the supply unit 4b via piping. The flow control section 4c controls the flow rate of the liquid 101 supplied by the supply section 4b. The flow controller 4c can be, for example, a flow control valve. The flow control unit 4 c can also start and stop the supply of the liquid 101 .

The liquid nozzle 4 d is provided inside the housing 6 . The liquid nozzle 4d has a cylindrical shape. One end of the liquid nozzle 4d is connected to the flow controller 4c via a pipe. The other end of the liquid nozzle 4d faces the surface 100b of the substrate 100 mounted on the mounting table 2a. Therefore, the liquid 101 ejected from the liquid nozzle 4 d is supplied to the surface 100 b of the substrate 100 .

Also, the other end of the liquid nozzle 4 d (ejection port for the liquid 101 ) is positioned substantially at the center of the surface 100 b of the substrate 100 . The liquid 101 ejected from the liquid nozzle 4 d spreads from substantially the center of the surface 100 b of the substrate 100 to form a liquid film having a substantially constant thickness on the surface 100 b of the substrate 100 . Note that the film of the liquid 101 formed on the surface 100b of the substrate 100 is hereinafter referred to as a liquid film.

The second liquid supply unit 5 supplies the liquid 102 (corresponding to an example of the second liquid) to the surface 100b of the substrate 100 . The second liquid supply section 5 has a liquid storage section 5a, a supply section 5b, a flow control section 5c, and a liquid nozzle 4d.

The liquid 102 can be used in the preliminary and thawing steps described below. Therefore, the liquid 102 is not particularly limited as long as it hardly reacts with the material of the substrate 100 and does not easily remain on the surface 100b of the substrate 100 in the drying process described below.

Further, as will be described later, it is preferable that the liquid 102 has a higher electrical conductivity than the liquid 101 . The liquid 102 can be, for example, a liquid in which a gas that ionizes when dissolved is dissolved. The liquid in which a gas that is ionized when dissolved can be, for example, a liquid in which carbon dioxide gas or ammonia gas is dissolved. Further, the liquid 102 may be, for example, low-concentration SC-1 (Standard Clean 1) diluted with pure water, choline (CHOLINE) aqueous solution, or TMAH (Tetramethyl ammonium hydroxide) aqueous solution.
Also, the liquid 102 may be a mixed liquid of the above-described liquid and a liquid 103 having a smaller surface tension than the above-described liquid. The liquid 103 is, for example, a surfactant-containing liquid, isopropyl alcohol (IPA), or the like.

The configuration of the second liquid supply section 5 can be the same as the configuration of the first liquid supply section 4, for example. For example, the liquid storage portion 5a can be the same as the liquid storage portion 4a described above. The supply unit 5b can be similar to the supply unit 4b described above. The flow control unit 5c can be the same as the flow control unit 4c described above.

In addition, since the liquid 102 is used in the preliminary process and the thawing process, the temperature of the liquid 102 can be made higher than the freezing point of the liquid 101 . Also, the temperature of the liquid 102 can be set to a temperature at which the frozen liquid 101 can be thawed. The temperature of the liquid 102 can be, for example, normal temperature (20° C.).

The housing 6 has a box shape. A cover 6 a is provided inside the housing 6 . The cover 6a receives the liquids 101 and 102 supplied to the substrate 100 and discharged to the outside of the substrate 100 as the substrate 100 rotates. The cover 6a has a tubular shape. The vicinity of the end of the cover 6a opposite to the mounting table 2a side (the vicinity of the upper end of the cover 6a) is bent toward the center of the cover 6a. Therefore, the liquids 101 and 102 splashing above the substrate 100 can be easily captured.

A partition plate 6 b is provided inside the housing 6 . The partition plate 6 b is provided between the outer surface of the cover 6 a and the inner surface of the housing 6 .

A plurality of outlets 6c are provided on the side surface of the housing 6 on the bottom side. In the case of the housing 6 illustrated in FIG. 1, two discharge ports 6c are provided. The used cooling gas 3a1, air 7a, liquid 101, and liquid 102 are discharged to the outside of the housing 6 from the discharge port 6c. An exhaust pipe 6c1 is connected to the exhaust port 6c, and an exhaust section (pump) 11 for exhausting the used cooling gas 3a1 and air 7a is connected to the exhaust pipe 6c1. A discharge pipe 6c2 for discharging the liquids 101 and 102 is connected to the discharge port 6c.

The outlet 6 c is provided below the substrate 100 . Therefore, the cooling gas 3a1 is discharged from the discharge port 6c to create a downflow flow. As a result, it is possible to prevent the particles from soaring.

In a plan view, the plurality of discharge ports 6c are provided symmetrically with respect to the center of the housing 6. As shown in FIG. By doing so, the exhaust direction of the cooling gas 3a1 becomes symmetrical with respect to the center of the housing 6. FIG. If the cooling gas 3a1 is discharged symmetrically, the cooling gas 3a1 can be discharged smoothly.

The air blower 7 is provided on the ceiling surface of the housing 6 . Note that the air blower 7 can also be provided on the side surface of the housing 6 as long as it is on the ceiling side. The blower section 7 can include a blower such as a fan and a filter. The filter can be, for example, a HEPA filter (High Efficiency Particulate Air Filter).

The control unit 9 controls the operation of each element provided in the substrate processing apparatus 1 . FIG. 2 illustrates an example of the configuration of the control section 9. As shown in FIG. The control unit 9 can be, for example, a computer having an arithmetic element such as a CPU (Central Processing Unit) and a storage unit 9c such as a semiconductor memory. For example, the mechanism control section 9a and the setting section 9b illustrated in FIG. 2 can be used as computing elements, and the memory section 9c can be used as a memory element. A control program for controlling the operation of each element provided in the substrate processing apparatus 1 can be stored in the storage element. The arithmetic element controls the operation of each element provided in the substrate processing apparatus 1 by using the control program stored in the storage element, the data input by the operator via the input/output screen (device) 8, and the like. do.

The control program and the data input by the operator are stored in the storage element after being set to the optimum state by the setting section 9b to be stored in the storage section 9c (storage element). Further, the setting unit 9b reconverts the data requested to be output by the operator into the optimum state for display on the input/output screen, and causes the input/output screen (device) 8 to display the data.

For example, the control unit 9 controls the operation of each element provided in the substrate processing apparatus 1 from the mechanism control unit 9a based on the control program stored in the storage unit 9c, thereby rotating the substrate 100 and cooling the cooling gas 3a1. , the supply of liquid 101 and the supply of liquid 102 are controlled.

For example, the control unit 9 controls the supply of the cooling gas 3a1, the supply of the liquid 101, and the supply of the liquid 102, thereby supplying the liquid 102 to the surface 100b of the rotating substrate 100, and performs a preliminary step of supplying the cooling gas 3a1 to the space between .

For example, the control unit 9 rotates the substrate 100 to discharge at least part of the liquid 102 supplied to the surface 100b of the substrate 100, and then changes the number of rotations so that the surface 100b of the substrate 100 from which the liquid 102 has been discharged is changed. A liquid film forming step is performed to form a liquid film by supplying the liquid 101 toward the .

For example, the control unit 9 executes a supercooling process to bring the liquid film on the surface 100b of the substrate 100 into a supercooled state.
For example, the control unit 9 executes a freezing step of freezing at least part of the liquid film on the surface 100b of the substrate 100. FIG.

For example, in the liquid film forming process, the control unit 9 causes a portion of the liquid 102 to remain when the liquid 102 is discharged, and supplies the liquid 101 on the remaining liquid 102 .

For example, the control unit 9 executes a thawing step of supplying the liquid 102 to the frozen liquid film and thawing the frozen liquid 101 .
Details of the contents of each step will be described later.

Next, the operation of the substrate processing apparatus 1 will be illustrated.
FIG. 3 is a timing chart for illustrating the action of the substrate processing apparatus 1. FIG.
FIG. 4 is a graph for illustrating temperature changes of the liquid 101 supplied to the substrate 100 in the freeze cleaning process.

3 and 4, the substrate 100 is a 6025 quartz (Qz) substrate (152 mm×152 mm×6.35 mm), the liquid 101 is pure water, and the liquid 102 is a liquid (carbonated water) in which carbon dioxide gas is dissolved. is the case.

First, the substrate 100 is loaded into the housing 6 through a loading/unloading port (not shown) of the housing 6 . The loaded substrate 100 is placed and supported on the plurality of supporting portions 2a1 of the placing table 2a.

After the substrate 100 is supported on the mounting table 2a, as shown in FIGS. 3 and 4, freeze cleaning including a preliminary step, a liquid film forming step, a cooling step (supercooling step+freezing step), a thawing step, and a drying step. process is performed.

First, preliminary steps are performed as shown in FIGS. In the preliminary process, the control unit 9 controls the supply unit 5b and the flow control unit 5c to supply the liquid 102 at a predetermined flow rate onto the surface 100b of the substrate 100. FIG. Further, the control unit 9 controls the flow rate control unit 3c to supply the cooling gas 3a1 at a predetermined flow rate to the rear surface 100a of the substrate 100. FIG. Further, the control unit 9 controls the driving unit 2c to rotate the substrate 100 at the second rotation speed.

Here, if the atmosphere in the housing 6 is cooled by the supply of the cooling gas 3a1 by the cooling unit 3, frost containing dust in the atmosphere may adhere to the substrate 100 and cause contamination. Since the liquid 102 is continuously supplied to the surface 100b of the substrate 100 in the preparatory step, the substrate 100 can be uniformly cooled and frost can be prevented from adhering to the surface 100b of the substrate 100. FIG.

For example, in the case of the example shown in FIG. 3, the rotation speed of the substrate 100 can be, for example, about 50 rpm to 500 rpm as the second rotation speed. Also, the flow rate of the liquid 102 can be set to about 0.1 L/min to 1.0 L/min. Also, the flow rate of the cooling gas 3a1 can be set to approximately 40 NL/min to 200 NL/min. Moreover, the process time of the preliminary process can be set to about 1800 seconds. It should be noted that the process time of the preparatory process may be any time during which the in-plane temperature of the substrate 100 becomes substantially uniform, and can be obtained by performing experiments or simulations in advance.

The temperature of the liquid film in the preliminary step is almost the same as the temperature of the supplied liquid 102 because the liquid 102 is in a flowing state. For example, if the temperature of the supplied liquid 102 is about normal temperature (20° C.), the temperature of the liquid film is about normal temperature (20° C.).

Next, as shown in FIGS. 3 and 4, a liquid film forming step is performed. In the liquid film forming process, the supply of the liquid 102 that has been supplied in the preliminary process is stopped. Then, since the rotation of the substrate 100 is maintained, the liquid 102 on the surface 100b of the substrate 100 is discharged. Then, the number of revolutions of the substrate 100 is reduced to the first number of revolutions slower than the second number of revolutions. The first rotation speed may be any rotation speed that can suppress variations in the thickness of the liquid film due to centrifugal force, and may be in the range of 0 to 50 rpm, for example. After the rotation speed of the substrate 100 is set to the first rotation speed, a predetermined amount of liquid 101 is supplied to the substrate 100 to form a liquid film. At this time, the liquid 102 is replaced with the liquid 101 . Note that the flow rate of the cooling gas 3a1 is maintained.

The thickness of the liquid film formed in the liquid film forming step (thickness of the liquid film when performing the supercooling step) can be about 200 μm to 1300 μm. For example, the controller 9 controls the supply amount of the liquid 101 so that the thickness of the liquid film on the surface 100b of the substrate 100 is approximately 200 μm to 1300 μm.

Next, as shown in FIGS. 3 and 4, a cooling process (supercooling process+freezing process) is performed. In the present embodiment, in the cooling process, the period from when the liquid film made of the liquid 101 reaches a supercooled state to before the freezing starts is called a "supercooling process", and the freezing of the liquid film in the supercooled state is performed. The period from the beginning until the freezing is completely completed is called the "freezing step".

First, in the supercooling step, the cooling gas 3a1 continuously supplied to the back surface 100a of the substrate 100 causes the temperature of the liquid film on the substrate 100 to drop further below the temperature of the liquid film in the liquid film forming step. state.

Here, if the cooling rate of the liquid 101 is too high, the liquid 101 will not be in a supercooled state and will freeze immediately. Therefore, the control unit 9 controls at least one of the rotation speed of the substrate 100 and the flow rate of the cooling gas 3a1 so that the liquid 101 on the surface 100b of the substrate 100 is supercooled.

The control conditions for the supercooled state of the liquid 101 are affected by the size of the substrate 100, the viscosity of the liquid 101, the specific heat of the cooling gas 3a1, and the like. Therefore, it is preferable to appropriately determine the control conditions under which the liquid 101 is in the supercooled state through experiments and simulations.

In the supercooled state, freezing of the liquid film starts due to, for example, the temperature of the liquid film, the presence of contaminants such as particles or air bubbles, vibration, and the like. For example, when contaminants such as particles are present, the liquid film starts to freeze when the temperature T of the liquid film is -35° C. or higher and -20° C. or lower. Also, by vibrating the liquid film by varying the rotation of the substrate 100 or the like, the freezing of the liquid film can be started.

When the supercooled liquid film starts to freeze, the supercooling process is shifted to the freezing process. In the freezing step, at least part of the liquid film on the surface 100b of the substrate 100 is frozen. In the freeze cleaning step of this embodiment, the case where the liquid film is completely frozen to form the frozen film 101a will be described.

Next, a decompression process is performed as shown in FIGS.
In the thawing process, the control unit 9 controls the supply unit 5b and the flow control unit 5c to supply the surface 100b of the substrate 100 with the liquid 102 at a predetermined flow rate. Further, the control unit 9 controls the flow rate control unit 3c to stop the supply of the cooling gas 3a1. As a result, the frozen film 101 a begins to be thawed, and the frozen film 101 a gradually becomes the liquid 101 . Further, the control unit 9 controls the drive unit 2c to increase the rotation speed of the substrate 100 to a third rotation speed higher than the second rotation speed. If the substrate 100 rotates faster, the liquids 101 and 102 can be shaken off by centrifugal force. Therefore, it becomes easy to discharge the liquids 101 and 102 from the surface 100 b of the substrate 100 . At this time, contaminants separated from the surface 100 b of the substrate 100 are also discharged together with the liquids 101 and 102 .

The amount of liquid 102 to be supplied is not particularly limited as long as it can be thawed. Further, the third rotation speed of the substrate 100 is not particularly limited as long as the liquid 101, the frozen liquid 101, the liquid 102 and contaminants can be discharged.

Next, a drying process is performed as shown in FIGS. In the drying process, the control unit 9 controls the supply unit 5b and the flow control unit 5c to stop the supply of the liquid 102. FIG. Further, the control unit 9 controls the drive unit 2c to further increase the rotational speed of the substrate 100 to a fourth rotational speed higher than the third rotational speed. The faster the substrate 100 rotates, the faster the substrate 100 can be dried. Note that the fourth number of revolutions of the substrate 100 is not particularly limited as long as the substrate can be dried.
The substrate 100 that has undergone freeze cleaning is carried out of the housing 6 through a loading/unloading port (not shown) of the housing 6 .
By doing so, one freeze cleaning step can be performed.

By the way, as described above, when a liquid having a low conductivity (for example, the liquid 101) is supplied to the surface 100b of the rotated substrate 100, static electricity is likely to be generated. In addition, on the surface 100b of the substrate 100, a pattern having conductivity, an element for insulating the pattern having conductivity, and the like may be formed. Therefore, the generated static electricity may cause dielectric breakdown or the like. In addition, there is a possibility that the pattern may be damaged by a chemical reaction caused by static electricity. Even in the case of a substrate (for example, a bulk substrate) before a pattern is provided, the surface 100b of the substrate 100 may be damaged due to a chemical reaction caused by static electricity.

In order to deal with such static electricity, there is known a technique of using a high-conductivity cleaning solution in which carbon dioxide is dissolved in pure water when spin cleaning the surface of the substrate. By using a cleaning liquid in which carbon dioxide is dissolved in pure water, generation of static electricity can be suppressed even if the cleaning liquid is supplied to the surface of a rotated substrate.

Therefore, the present inventors tried the above-described cooling process of the freeze cleaning process using the liquid 102, which is carbonated water, and found that the removal rate was lower than when the cooling process of the freeze cleaning process was performed using pure water. found.

The mechanism of why the removal rate is lower when the freeze-cleaning process is performed with the liquid 102, which is a conductive liquid, is lower than when the freeze-cleaning process is performed with pure water is not necessarily clear, but is as follows. can be thought of as

Freezing of the liquid 101 is considered to occur starting from contaminants such as particles. By freezing the liquid 101 with the contaminant as a starting point, the contaminant can be incorporated into the frozen liquid 101 . The liquid 101 changes its volume when frozen. As a result, the contaminant, which has become the starting point of freezing, has a force that separates it from the surface of the substrate 100 , so that the contaminant can be separated from the surface 100 b of the substrate 100 .

Also, when the liquid 101 changes to a solid, the volume changes and pressure waves are generated. It is believed that this pressure wave separates contaminants adhering to the surface 100b of the substrate 100 .
The liquid 101 in the supercooled state also has the property that a change in density due to non-uniform temperature of the liquid film, the presence of contaminants such as particles or air bubbles, vibration, or the like causes the start of freezing. In other words, the origin of freezing is not limited to contaminants.

By the way, in the liquid 102 , there is dissolved a gas that is ionized when dissolved in the liquid 102 . Therefore, gas bubbles may be included in the liquid 102 or bubbles may be generated in the liquid 102 . Further, since SC-1 is a mixed liquid of ammonia water and hydrogen peroxide water, gas bubbles may be contained in the liquid 102 or bubbles may be generated in the liquid 102 . As mentioned above, air bubbles can also initiate freezing. Therefore, if there are air bubbles in the liquid 102, the liquid 102 freezes with the air bubbles as the starting points, making it difficult to freeze the contaminants as the starting points.

The inventors of the present invention have found that, in the freeze cleaning (freeze cleaning step of the present embodiment) in which the liquid is frozen after passing through a supercooled state, it is preferable that the liquid to be frozen is a liquid that does not easily generate air bubbles.

However, if the freeze cleaning process is performed simply with a liquid that does not easily generate air bubbles, such as pure water, the problem of static electricity described above may occur. Therefore, the present inventors have extensively studied the mechanism of static electricity generated by a low-conductivity liquid. As a result, it was found that the generation of static electricity is caused by the flow of a low-conductivity liquid, and that the generation of static electricity can be suppressed if the liquid is not made to flow.

In the freeze washing process of the present embodiment, there are a process in which the liquid is made to flow and a process in which the liquid is not made to flow or is hardly made to flow. In the process of making the liquid flow, the generation of static electricity is suppressed by using a liquid with high conductivity. It does not lead to pattern breakage, substrate damage, etc., and even pure water with low conductivity, for example, poses no problem. Therefore, even if the liquid film is formed using a liquid that does not contain many bubbles, such as pure water, it is possible to maintain a high removal rate of contaminants while suppressing the generation of static electricity.

In the freeze cleaning step of the present embodiment, the conductive liquid 102 is supplied to the surface 100b of the substrate 100 in the preliminary step, the liquid 102 on the surface 100b of the substrate 100 is discharged in the liquid film forming step, After that, the substrate 100 was rotated at the first rotation speed, and the liquid 101 was supplied to form a liquid film.

By using the liquid 102 in the preliminary process, the in-plane temperature of the substrate 100 can be made substantially uniform while suppressing the generation of static electricity on the surface 100b of the substrate 100 .
Further, by setting the temperature of the liquid 102 to a temperature higher than the freezing point of the liquid 101, the liquid 101 can be supercooled when the liquid 101 is supplied to form the liquid film in the liquid film forming process. It is possible to prevent freezing without being done.

In addition, in the liquid film forming process, the removal rate of contaminants can be maintained by supplying the liquid 101 to the surface 100b of the substrate 100 to form the liquid film. Since the liquid 101 is a liquid in which air bubbles are less likely to occur, it is possible to suppress the occurrence of freezing starting from the air bubbles.
As a result, it becomes easier to freeze the contaminants as a starting point, so that the removal rate of the contaminants can be improved compared to the case where the liquid 102 is frozen.

Further, in the liquid film forming process, if the number of revolutions of the substrate 100 is set to be equal to or less than the first number of revolutions, when the liquid 101 is supplied to the surface 100b of the substrate 100, the gap between the liquid 101 and the surface 100b of the substrate 100 will increase. friction can be suppressed. Therefore, it is possible to suppress the generation of static electricity. In addition, since the influence of centrifugal force due to rotation can be suppressed, the supplied liquid 101 spreads over the surface 100b of the substrate 100, facilitating the formation of a liquid film having a uniform thickness. Furthermore, by stopping the rotation of the substrate 100, the generation of static electricity and variations in the thickness of the liquid film due to centrifugal force can be further suppressed.

Further, in the liquid film forming process, the liquid 102 on the surface 100b of the substrate 100 may be completely discharged, or the liquid 102 may be left to cover the surface 100b of the substrate 100. FIG. If the conductive liquid 102 remains on the surface 100 b of the substrate 100 , the liquid 101 can be supplied onto the conductive liquid 102 . By doing so, the generation of static electricity when the liquid 101 is supplied to the surface 100b of the substrate 100 can be further suppressed.

In addition, the supply of the cooling gas 3a1 is maintained in the liquid film forming process. Therefore, if the conductive liquid 102 remains on the surface 100b of the substrate 100, frost can be prevented from occurring on the surface of the substrate 100, and the in-plane temperature of the substrate 100 can be made substantially uniform in the preliminary process. You can also keep the status.

However, if the residual amount of the liquid 102 becomes too large, there is a possibility that bubbles may be generated in the formed liquid film. Therefore, the thickness of the film of the remaining liquid 102 is preferably 10% or less of the thickness of the liquid film formed in the liquid film forming step. If the thickness of the film of the remaining liquid 102 is 10% or less of the thickness of the formed liquid film, even if bubbles are generated, the effect on the contaminant removal rate can be greatly reduced.

In addition, since the shape of the contaminant is film-like, when the contaminant is adsorbed on the surface 100b of the substrate 100, when the surface 100b of the substrate 100 or the contaminant is superhydrophobic, or when the surface of the substrate 100 When 100b and the contaminant are superhydrophobic, the liquid 101 cannot enter between the substrate 100 and the contaminant in the process of forming the liquid film, and the contaminant cannot be separated from the surface 100b of the substrate 100. There is a risk.

In such a case, if the liquid 102 containing the liquid 103 with a small surface tension is used in the preliminary process, the liquid 102 containing the liquid 103 can enter between the substrate 100 and the contaminants. If the liquid 102 containing the liquid 103 is present between the substrate 100 and the contaminant, the liquid will be present between the substrate 100 and the contaminant when the liquid 101 is supplied to the surface 100b of the substrate 100 in the liquid film formation process. 101 will be able to invade. Therefore, when contaminants are adsorbed to the surface 100b of the substrate 100, when the surface 100b of the substrate 100 or the contaminants are superhydrophobic, or when the surface 100b of the substrate 100 and the contaminants are superhydrophobic However, the contaminants can be separated from the surface 100b of the substrate 100. FIG. That is, even in the case described above, the removal rate of contaminants can be improved while suppressing the generation of static electricity on the surface 100b of the substrate 100. FIG.

Also, in the thawing process, the liquid 102 is supplied to the surface 100b of the substrate 100. FIG. As described above, since the liquid 102 is conductive, it is possible to suppress the generation of static electricity even when the liquid 102 is supplied to the substrate 100 whose rotation speed is increased.

Note that the freeze washing step may be performed multiple times.
FIG. 5 is a flow chart when the freeze washing process is performed multiple times.
As shown in FIG. 5, if the next freezing and cleaning step is to be carried out, the thawing step should be carried out before returning to the liquid film forming step.

The operation of the control section 9 in this case will be described with reference to FIG.
FIG. 6 is a flow chart explaining the operation of the control section 9 when the freeze cleaning process is performed multiple times.
The number of repetitions of the freeze cleaning process is stored in advance in the storage unit 9c by the operator.

As shown in FIG. 6, first, the liquid film formation steps (S001 to S004) are performed after the preliminary steps are performed.
Next, the control part 9 implements a cooling process. In the cooling step, detection data is obtained from a detection unit (not shown) to determine whether the liquid film has frozen (S005). The detection data may be the temperature of the liquid film, the thickness of the liquid film, or the cloudiness of the liquid film. If it is determined that the liquid film is not frozen even after the predetermined time has passed, a warning is output and the apparatus is stopped.

When the control unit 9 determines that the liquid film is frozen, it determines whether or not the predetermined number of repetitions of the freeze cleaning process has been reached (S006). If the next freeze cleaning process is performed, the second liquid supply unit 5 is controlled to supply the liquid 102 to the surface 100b of the substrate 100 while maintaining the supply of the cooling gas 3a1 even in the thawing process (S006a ). By doing so, the same state as in the preliminary process can be generated. Therefore, as shown in FIG. 5, the preliminary step and the drying step in the next freeze washing step can be omitted.

Therefore, when the freeze cleaning process is repeated a plurality of times, the freeze cleaning process includes a liquid film forming process for forming a liquid film having a predetermined thickness on the surface 101b of the substrate 100, and a liquid film forming process for forming a liquid film having a predetermined thickness on the surface 101b of the substrate 100. A supercooling step of making a certain liquid film into a supercooled state, a freezing step of freezing at least part of the liquid film, and a liquid film frozen by supplying a conductive liquid 102 to the frozen film 101a on the surface 100b of the substrate 100. and a thawing step of thawing.

By doing so, by using the conductive liquid 102 in the thawing process that also serves as a preliminary process, it is possible to suppress the generation of static electricity even if the freeze cleaning process is repeatedly performed. Also, since the liquid 101 containing no air bubbles is frozen from the supercooled state, the contaminant removal rate can be maintained. As a result, the number of repetitions of the freeze cleaning process can be reduced, so that the operating rate of the substrate processing apparatus 1 can be improved.

FIG. 7 is a schematic diagram for illustrating a substrate processing apparatus 1a according to another embodiment.
As shown in FIG. 7, the substrate processing apparatus 1a further has a third liquid supply section 15. As shown in FIG. The third liquid supply unit 15 supplies a liquid 103 with a low surface tension to the surface 100b of the substrate 100 . The liquid 103 is, for example, a surfactant-containing liquid, isopropyl alcohol (IPA), or the like.

In the case of the substrate processing apparatus 1 described above, the liquid 102 (mixed liquid) containing the liquid 103 with low surface tension was supplied to the surface 100b of the substrate 100 by the second liquid supply section 5 . On the other hand, in the case of the substrate processing apparatus 1a, the liquid 102 is supplied to the surface 100b of the substrate 100 by the second liquid supply section 5, and the liquid 103 is supplied to the surface 100b of the substrate 100 by the third liquid supply section 15. are supplied to generate a liquid 102 (mixed liquid) containing the liquid 103 on the surface 100 b of the substrate 100 .

The third liquid supply section 15 has a liquid storage section 15a, a supply section 15b, a flow control section 15c, and a liquid nozzle 15d.
The configuration of the third liquid supply section 15 can be, for example, the same as the configuration of the second liquid supply section 5, so the description thereof will be omitted.

FIG. 8 is a timing chart for illustrating the action of a substrate processing apparatus 1a according to another embodiment.
The substrate processing apparatus 1a uses two different types of liquids 102 and 103 in the preliminary process. For example, at the start of the preliminary process, the control unit 9 controls the supply unit 5b and the flow control unit 5c to supply, for example, carbonated water (liquid 102) to the surface 100b of the substrate 100 from the liquid nozzle 4d. The control of the cooling gas 3a1 and the control of the rotation speed of the substrate are the same as those of the substrate processing apparatus 1. FIG. In this case, the liquid nozzle 15d is moved near the outer circumference of the substrate 100 by a drive unit (not shown).

After supplying the carbonated water for a predetermined time, the control unit 9 controls the supply unit 5b and the flow control unit 5c to stop the supply of carbonated water, controls the supply unit 15b and the flow control unit 15c, and controls the liquid nozzle 15d. supply a liquid 103 having a surface tension smaller than that of carbonated water. In this case, the control unit 9 controls the driving unit (not shown) to move the liquid nozzle 4d to the vicinity of the outer periphery of the substrate 100, and move the liquid nozzle 15 to a position facing substantially the center of the surface 100b of the substrate 100. .

The liquid 103 supplied from the liquid nozzle 15 d to the surface 100 b of the substrate 100 becomes a mixed liquid with the liquid 102 on the surface 100 b of the substrate 100 . For example, a liquid in which carbon dioxide gas or ammonia gas is dissolved, SC-1 (Standard Clean 1) , choline (CHOLINE), a mixture of at least one of TMAH (Tetramethyl ammonium hydroxide) aqueous solution and a surfactant, and isopropyl alcohol. (IPA) and at least one of them.

As described above, if the liquid 102 containing the liquid 103 is used in the preliminary step, if contaminants are adsorbed on the surface 100b of the substrate 100, if the surface 100b of the substrate 100 or the contaminants are superhydrophobic, Alternatively, even if the surface 100b of the substrate 100 and the contaminant are superhydrophobic, the liquid 101 to be frozen can easily enter between the substrate 100 and the contaminant.

The conductivity of the liquid 102 containing the liquid 103 decreases as the mixing ratio of the liquid 103 increases. Therefore, by supplying the liquid 103 with low surface tension after supplying the carbonated water (liquid 102) in the preliminary step, the supply time of the liquid 103 with low surface tension can be shortened. In this case, it is preferable that the carbonated water is supplied to the surface 100b of the substrate 100 longer than the liquid 103 is supplied. For example, the carbonated water is supplied for 300 to 1500 seconds, and the liquid 103 is supplied for 30 to 180 seconds. By doing so, in addition to the effects of the above-described embodiments, the generation of static electricity on the surface 100b of the substrate 100 can be further suppressed.

After the preliminary process, the control unit 9 controls the driving unit (not shown) to move the liquid nozzle 15d to the vicinity of the outer periphery of the substrate 100, and move the liquid nozzle 4d to a position facing substantially the center of the surface 100b of the substrate 100. . Then, the step of forming a liquid film is performed.
The liquid film forming process is the same as that of the substrate processing apparatus 1 . Carbonated water used in the preliminary process remains in the liquid nozzle 4d and the pipe. Therefore, while the liquid 103 is being supplied from the liquid nozzle 15d to the surface 100b of the substrate 100, it is preferable to discharge the carbonated water remaining in the liquid nozzle 4d and the piping and replace it with the liquid 101.

In the thawing process, the control unit 9 controls the supply unit 5b and the flow control unit 5c to supply the surface 100b of the substrate 100 with carbonated water (liquid 102) at a predetermined flow rate. Control of the cooling gas and control of the rotational speed of the substrate are the same as in the substrate processing apparatus 1 . Also, the drying process is the same as that of the substrate processing apparatus 1 .

A conductive liquid 102 a that does not react with the substrate 100 is supplied from the second liquid supply unit 5 to the surface 100 b of the substrate 100 , and a conductive liquid is supplied from the third liquid supply unit 15 . , a liquid 102b having a small surface tension may be supplied to the surface 100b of the substrate 100. FIG.

The liquid 102 a is, for example, carbonated water or a mixture of carbonated water and the liquid 103 .
The liquid 102b is, for example, a low concentration SC-1 (Standard Clean 1), a choline (CHOLINE) aqueous solution, a TMAH (Tetramethyl ammonium hydroxide) aqueous solution, or a mixture of these solutions and the liquid 103.

The liquid 102b is a conductive liquid with a small surface tension. Therefore, the use of the liquid 102b has the effect of suppressing the generation of static electricity on the surface 100b of the substrate 100 and facilitating the penetration of the liquid 101 between the substrate 100 and contaminants. However, liquid 102b may etch surface 100b of substrate 100 .

Therefore, in the preliminary step, by supplying the liquid 102b after supplying carbonated water (liquid 102a), the supply time of the liquid 102b, which may etch the surface 100b of the substrate 100, can be shortened. In this case, it is preferable that the time for which the carbonated water is supplied to the surface 100b of the substrate 100 is longer than the time for which the liquid 102b is supplied. For example, the carbonated water is supplied for 300 to 1500 seconds, and the liquid 102b is supplied for 30 to 180 seconds.

By doing so, the following effects can be obtained in addition to the effects of the above-described embodiment. That is, when contaminants are adsorbed to the surface 100b of the substrate 100, when the surface 100b of the substrate 100 or the contaminants are superhydrophobic, or when the surface 100b of the substrate 100 and the contaminants are superhydrophobic Even if there is, it is possible to further improve the removal rate of contaminants while suppressing etching of the surface 100b of the substrate 100 .

In this case, the liquid film forming process, thawing process, and drying process are the same as those of the substrate processing apparatus 1 . In addition, in the thawing process, the liquid 102a may be used, or the liquid 102b may be used.

The embodiments have been illustrated above. However, the invention is not limited to these descriptions. Regarding the above-described embodiments, those in which those skilled in the art appropriately add, delete, or change the design of components, or add, omit, or change the conditions of steps, as long as they have the features of the present invention. , are included in the scope of the present invention.

For example, the shape, size, number, arrangement, etc. of each element provided in the substrate processing apparatus 1 are not limited to those illustrated and can be changed as appropriate.
For example, in the preliminary process, the substrate need not always be rotated at the second rotation speed, and may be rotated at the first rotation speed or less. In this case, the number of revolutions is set to the second number of revolutions and at least part of the liquid 102 may be discharged immediately before moving to the step of forming the liquid film.
In the thawing step, thawing does not necessarily have to be started on the frozen film 101a. For example, thawing is started when the liquid 101 is partially frozen from the supercooled state (solid-liquid phase state). You may do so.

Reference Signs List 1 substrate processing apparatus 1a substrate processing apparatus 2 mounting section 3 cooling section 3a1 cooling gas 4 first liquid supply section 5 second liquid supply section 6 housing 8 detection section 9 control section 10 gas supply unit 10d gas 100 substrate 100a rear surface 100b front surface 101 liquid 101a frozen film 102 liquid 103 liquid

Claims (6)

a mounting table on which the substrate can be rotated;
a cooling unit capable of supplying a cooling gas to a space between the mounting table and the substrate;
a first liquid supply unit capable of supplying a first liquid to a surface of the substrate opposite to the mounting table;
a second liquid supply unit capable of supplying a second liquid having a higher conductivity than the first liquid to the surface of the substrate;
a control unit that controls rotation of the substrate, supply of the cooling gas, supply of the first liquid, and supply of the second liquid;
with
By controlling the supply of the cooling gas, the supply of the first liquid, and the supply of the second liquid,
a preliminary step of supplying the second liquid to the surface of the substrate and supplying the cooling gas to a space between the mounting table and the substrate;
After the preliminary step, a liquid film forming step of supplying the first liquid toward the surface of the substrate to form a liquid film;
a supercooling step of bringing the liquid film on the surface of the substrate into a supercooled state;
a freezing step of freezing at least a portion of the liquid film on the surface of the substrate;
and run
In the step of forming the liquid film,
after stopping the supply of the second liquid, rotating the substrate at the rotational speed of the preliminary step to discharge at least part of the second liquid supplied to the surface of the substrate;
a substrate processing apparatus for supplying the first liquid toward the surface of the substrate after discharging at least a part of the second liquid and then setting the rotation number to a first rotation number lower than the rotation number of the preliminary step; . In the liquid film forming step, the control unit causes the substrate to rotate to discharge at least part of the second liquid supplied to the surface of the substrate, and the second liquid is discharged. 2. A substrate processing apparatus according to claim 1, wherein said first liquid is supplied toward said surface of said substrate. In the liquid film forming step, the control unit causes a part of the second liquid to remain when the second liquid is discharged, and supplies the first liquid onto the remaining second liquid. 3. The substrate processing apparatus according to claim 2. The control unit
a thawing step of supplying the second liquid to the frozen liquid film on the surface of the substrate to thaw the frozen liquid film;
4. The substrate processing apparatus according to claim 1, further comprising: 5. The substrate processing apparatus according to claim 1, wherein the second liquid is a liquid in which gas that is ionized when dissolved is dissolved. The substrate processing apparatus according to any one of claims 1 to 4, wherein the first rotation speed is to stop rotation of the substrate.

Images