JP3425895B2 - Rotary substrate drying apparatus and drying method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary substrate drying apparatus and a substrate drying method that utilize centrifugal force.

[0002]

2. Description of the Related Art In a manufacturing process of a TFT (thin film transistor) panel used in a liquid crystal display device, cleaning with pure water and drying are performed between the respective processes. For this drying, a rotary substrate drying device is usually used. Figure 8
FIG. 4 is a cross-sectional view showing an outline of a conventional general rotary substrate drying apparatus. In FIG. 8, the substrate 6 is a substrate chuck 7
It is held horizontally above and is rotated together with the substrate chuck 7 by driving the spin motor 8. Also, the substrate chuck 7
A nozzle 17 for spraying an inert gas such as nitrogen gas from directly above is provided above the center of the main surface of the substrate 6. The pure water 14 on the substrate 6 is shaken off by the centrifugal force generated by the rotation. Further, by spraying the inert gas from the nozzle 17, the pure water remaining near the center of the substrate where the centrifugal force is weak is dried. The spin cup 9 is for preventing the pure water 14 from scattering from the substrate 6 and for efficiently draining and exhausting it, and has a cylindrical shape that covers the outer periphery of the substrate chuck 7. The pure water scattered from the substrate 6 by the centrifugal force hits the inner wall of the spin cup 9 and bounces off. Spin cup 9
Due to the functions of the bounce prevention ring 10 and the baffle plate 11 provided inside, pure water is drained from the drain port 12 below the spin cup, and gas is exhausted from the exhaust port 13 below the spin cup.

A general drying procedure using the above conventional rotary type substrate drying apparatus will be described below. After fixing the substrate 6 to which the pure water 14 is attached to the substrate chuck 7, the substrate is first rotated at a low speed (about 500 rpm or less) and the pure water 14 on the surface is rotated.
Shake lightly. Then, after the surface pure water is reduced, it is rotated at a high speed (about 1000 to 1500 rpm), and at the same time, an inert gas is blown to the center of the substrate where centrifugal force is hard to work to dry it.

[0004]

However, when the conventional rotary type substrate drying apparatus is used to perform the drying in the above-described general procedure, the following problems cannot be solved by the above-mentioned conventional known techniques. There is a problem. When shaking off at low speed, a large amount of pure water on the substrate
It splatters from the substrate, hits the spin cup, bounces, and reattaches to the substrate. During high-speed rotation, a large amount of mist is generated from the pure water remaining on the substrate. During high-speed rotation, airflow with a constant flow is generated in the cup due to the wind blow of the substrate, but at the same time the flow is disturbed by blowing the gas from the nozzle, the efficient exhaust cannot be performed, and the mist spins. Remaining in the cup,
Reattach to the dried substrate. In particular, since the size of substrates related to liquid crystals has been increased in recent years, these problems tend to become more prominent, and the conventional rotary substrate drying apparatus is susceptible to redeposition of pure water and mist. The redeposited pure water or mist causes a pattern defect, resulting in a decrease in yield and quality.

Japanese Patent Laid-Open No. 9-152272 discloses one of the known techniques for preventing traces of water droplets remaining on the substrate after drying and contaminating the substrate surface. In this publication, in a rotary substrate drying apparatus that rotates a substrate and sprays gas onto the substrate to dry the substrate, the substrate is rotated at a high speed after the main surface of the substrate is uniformly wetted, and after a predetermined time has elapsed. Water droplets are attached to the central area of the upper and lower surfaces of the substrate at the timing (when the liquid layer attached to the main surface of the substrate is almost uniform and thin) by blowing out (blowing) gas such as air or nitrogen. A rotary substrate drying method and apparatus capable of performing drying with high cleanability without leaving a mark is disclosed. In addition, as one of the known techniques for preventing contamination and the like due to redeposition of mist on a substrate, Japanese Patent Laid-Open No. 1-58200
There is a publication of 0-64875. In this publication, while rotating the substrate, a gas is blown from the nozzle onto the main surface of the substrate, and the nozzle is moved in parallel or in an arc shape from the center of rotation of the substrate to the outside, thereby rotating the substrate. A rotary substrate drying apparatus and a substrate drying method for preventing reattachment of mist to a substrate are disclosed.

However, since the methods described in any of these publications perform high-speed rotation and gas blowing while a large amount of liquid adheres to the substrate, a large amount of mist is generated and the exhaust gas flow is also increased. However, the above-mentioned problems cannot be effectively solved. An object of the present invention is to solve the above-mentioned problems of the prior art and to enable removal of particles inside the drying device, the purpose of which is to achieve improvement in yield and quality. A substrate drying apparatus and a drying method are provided.

[0007]

A rotary substrate drying apparatus according to the present invention includes a substrate chuck for holding a substrate horizontally, a spin motor for rotating the substrate chuck around the center of rotation of the chuck, and a spin motor on the substrate. It is characterized in that it has an air knife capable of blowing out high-pressure gas, and an exhaust pipe in proximity to the air knife and integrally held with the air knife for exhausting high-pressure gas blown out from the air knife. Further, preferably, a vertical drive mechanism for vertically moving the air knife and the exhaust pipe, and a horizontal movement mechanism for horizontally moving the air knife and the exhaust pipe are further provided. Further, preferably, a plurality of sets of the air knife and the exhaust pipe are arranged in parallel.

Further, in the rotary substrate drying method according to the present invention, (1) while the substrate is stopped, a high pressure gas is blown onto the surface of the substrate from an air knife close to the substrate, and the substrate is placed close to the air knife. A first drying process of exhausting air through an exhaust pipe; (2) a second drying process of rotating the substrate at a low speed; and (3) a third drying process of rotating the substrate at a high speed. It has a feature.

Further, in another method for drying a rotary substrate according to the present invention, (1) in a spin cup which is a closed space, a high pressure gas is downflowed by an air knife while exhausting the air so that the atmosphere in the spin cup is reduced. A step of cleaning, (2) a step of mounting a wet substrate in the spin cup, and (3) a high-pressure gas on the surface of the substrate from the air knife close to the substrate with the substrate stopped. (4) a first drying step in which the air is sprayed and exhausted through an exhaust pipe arranged in the vicinity of the air knife;
It is characterized by comprising a second drying step of rotating the substrate at a low speed and (5) a third drying step of rotating the substrate at a high speed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a rotary substrate drying apparatus showing a first embodiment of the present invention, and FIG. 2 is a plan view thereof. In FIG. 1, the structure and functions of the substrate 6, the substrate chuck 7, the spin motor 8 and the like in the spin cup 9 are the same as those of the conventional example shown in FIG. 8, and therefore detailed description thereof will be omitted. In the present embodiment, the air knife 1 and the exhaust pipe 2 are provided on the spin cup 9, which are horizontally moved by the slide mechanism 4 and vertically moved by the vertical drive mechanism 5.
Move as a unit. As shown in FIG. 1, the attachment angle of the air knife is preferably an angle of about 45 degrees at which the high pressure air from the air knife effectively acts on the substrate surface. The exhaust pipe 2 is arranged at a position where the high-pressure air blown out from the air knife 1 can be efficiently exhausted. With the exhaust pipe 2 shown in FIG. 2 and the exhaust hose 3 attached to the exhaust pipe, the high pressure air blown from the air knife 1 and a part of the mist generated during the pure water removal drying on the substrate by the air knife 1 are removed. Exhaust outside the dryer.

Next, the drying procedure by the rotary substrate drying apparatus according to the first embodiment of the present invention will be briefly described with reference to FIG. As shown in FIG. 1, the air knife 1 and the exhaust pipe 2 are removed from the outside of the spin cup 9 in a state in which the substrate 6 before drying having a large amount of pure water on the surface is fixed on the substrate chuck 7 and stopped. The slide mechanism 4 and the vertical drive mechanism 5 move the substrate 6 in the spin cup 9 to the substrate end surface (the position of the right air knife and the exhaust pipe shown by the one-dot chain line in FIG. 1) where the substrate is dried by the air knife. Next, high-pressure air with controlled cleanliness is blown from the air knife 1,
Further, while sucking it by the exhaust pipe 2 arranged in the forward direction of the air knife 1, it is moved by the slide mechanism 4 to the opposite substrate end face (the position of the left air knife and the exhaust pipe shown by the one-dot chain line in FIG. 1). . Then, the air knife 1 and the exhaust pipe 2 stop blowing and exhausting the high-pressure air, and move the high-pressure air to the outside of the spin cup 9 (the position shown by the solid line in FIG. 1). Since the end surface and the back surface of the substrate 6 cannot be dried only by the air knife 1 and the exhaust pipe 2, the substrate 6 is rotated at a low speed by the spin motor 8 and the water droplets remaining on the end surface and the back surface of the substrate 6 are shaken off. Then, it is dried at high speed.

It is the surface (the upper surface of the substrate 6 in FIG. 1) that has a large amount of pure water deposited on the substrate 6 before drying, and the substrate 6 before the rotation processing.
By removing and drying a large amount of pure water on the surface with the air knife 1, it is possible to suppress the generation amount of mist scattered at low speed and high speed rotation. Further, it is not necessary to blow an inert gas such as nitrogen gas to the center of the substrate 6 where centrifugal force is hard to work, which is required in the conventional rotary substrate drying device, and to disturb a constant flow of air generated during the rotation process. There is no. Therefore, the air can be efficiently exhausted, so that the mist in the spin cup 9 can be removed, and the reattachment of the mist to the substrate 6 can be prevented.

Next, the first embodiment of the drying method according to the present invention will be described more specifically along the drying sequence. FIG. 3 is a drying sequence of the first embodiment of the drying method of the present invention. The flow rate of high pressure air from the air knife,
The drying time by the air knife, the low speed rotation and the high speed rotation depend on the size of the substrate and the like. here,
As an example, a sequence for drying a 36 cm wide substrate will be described with reference to FIG. 1 and along the sequence of FIG. Sequence 1 The air knife 1 and the exhaust pipe 2 are slid from the outside of the spin cup 9 while the substrate 6 before drying, which has a large amount of pure water on the dried surface of the air knife, is fixed on the substrate chuck 7 and stopped. Then, by the vertical drive mechanism 5, the spin cup 9 is moved to the end surface of the substrate 6 where the removal and drying by the air knife is started.
At this time, the clearance between the air knife 1 and the substrate 6 is, for example, 10
It is set so as to be parallel when the distance is less than or equal to mm. High-pressure air whose cleanliness is controlled is blown from the air knife 1, and while being sucked by the exhaust pipe 2 arranged in the forward direction of the air knife 1, it is moved to the opposite end face of the substrate by the slide mechanism 4, and the surface of the substrate 6 is moved. To dry. The flow rate of high pressure air is preferably about 100 to 200 l / min.
Make sure that the exhaust volume of is commensurate with it. The speed at which the air knife is slid is set to about 100 cm / min, but it is necessary to finally set the conditions depending on the dry state. After that, the air knife 1 and the exhaust pipe 2 stop the high-pressure air blowing and the exhaust, and move the air out of the spin cup 9.

Sequence 2 Since the edge surface and the back surface of the substrate 6 cannot be dried only by the low-speed rotation drying air knife 1 and the exhaust pipe 2, the substrate 6 is further rotated at a low speed by the spin motor 8 to remove water droplets remaining on the substrate end surface and the back surface. Shake off. The rotation speed at low speed is preferably as low as possible so that the water droplets scattered from the substrate 6 do not bounce on the spin cup 9 and reattach to the substrate 6, 500 rpm
The following level is preferable. Further, the drying time T1 due to the low speed rotation is a time in which the water droplets on the end surface and the back surface of the substrate 6 are shaken off, and therefore 5 seconds or less is sufficient. Sequence 3 High-speed rotation drying It is desirable that the number of rotations at high speed is as low as possible in consideration of suppressing damage to the substrate due to centrifugal force.
The rotation time T2 for high-speed rotation is about 10 seconds, with about 00 to 1500 rpm as a guide.

Up to now, the drying method of drying the entire surface of the substrate with the air knife has been described. However, not the entire surface but the central portion of the substrate is partially dried, and the drying is performed by rotation in the next step. Even if the portion other than the central portion of the substrate is dried, a sufficient effect can be obtained. As a method for performing partial drying, the air knife shown in FIGS. 1 and 2 may be used for drying only the central portion by a slide mechanism. According to this method, it is possible to shorten the drying time with the air knife. Further, the number of air knives and exhaust pipes is not limited to one, and a plurality of air knives and exhaust pipes may be arranged to perform surface drying before drying by rotation. By arranging a plurality of the air knives and exhaust pipes shown in FIG. 2 side by side so that they can be moved simultaneously by the slide mechanism 4 and the vertical drive mechanism 5, the drying time by the air knives can be shortened. Furthermore, during high-speed rotary drying of the substrate (third drying process), an air knife may be positioned in the central portion of the substrate, and high-pressure air may be blown to efficiently dry the central portion of the substrate where centrifugal force is less likely to be applied. . In this case, after the completion of the third drying process, the air knife and the exhaust pipe rise and return to the position shown by the solid line in FIG.

FIG. 4 is a diagram for explaining the drive mechanism of the air knife used in the second embodiment of the drying device of the present invention. As shown in FIG. 4, the air knife 1 is attached to the up-and-down drive mechanism 5 so as to be rotatable about a rotary shaft 15, and is driven by a drive motor (not shown) as shown by a dashed line in the drawing. Is configured so that it can be directed directly below. This is because before the drying, the blowout port of the air knife 1 is directed downward so that the high-pressure air can be blown out from the air knife.

FIG. 5 is a sectional view showing a second embodiment of the rotary substrate drying apparatus of the present invention. In FIG. 5, three air knives 1 and three exhaust pipes 2 are arranged in parallel. The slide mechanism 4 and the vertical drive mechanism 5 move the above three sets of air knives and exhaust pipes in the parallel and vertical directions in the figure. The structure and function inside the spin cup 9 and the substrate 6, the substrate chuck 7, the spin motor 8 and the like are the same as those in the first embodiment shown in FIG. 1, and therefore detailed description thereof is omitted. . The air knife 1, the exhaust pipe 2, the slide mechanism 4, and the vertical drive mechanism 5 are surrounded by a cylindrical enclosing plate 16 having a ceiling plate and enclosing the outer periphery of the spin cup 9. Here, the spin cup 9 and the surrounding plate 16 constitute a drying chamber.

A second embodiment of the rotary substrate drying method according to the present invention will be described with reference to FIG. Before drying, the air knife 1 and the exhaust pipe 2 are arranged at the position shown by the one-dot chain line in the upper part of the enclosure plate 16 by the slide mechanism 4 and the vertical drive mechanism 5. At this position, the outlet of the air knife is directed right below and sends high pressure air at a flow rate of about 30 to 100 l / min which is smaller than the flow rate of the high pressure air of the air knife performed in the first embodiment described in FIG. . When sending a small amount of high-pressure air, it is preferable to stop the exhaust of the exhaust pipe 2 in order to stabilize the air flow in the enclosure plate. The high-pressure air whose cleanness is controlled from the air knife flows down in the enclosure plate 16, passes through the spin cup 9, and is exhausted from the exhaust port 13 on the bottom surface of the spin cup. In this process, the particles in the space surrounded by the enclosing plate 16 are discharged from the exhaust port 13 under the spin cup together with the downflow, and the air in the drying chamber is cleaned. The flow rate of high-pressure air from the air knife 1 at this time is determined by the distance between the air knife and the substrate, the volume of the space inside the partition plate 16, and the like. That is, the flow rate is set so that downflow is performed in the enclosure plate 16 and the exhaust air under the spin cup is sufficiently exhausted to clean the air in the drying chamber constituted by the enclosure plate 16 and the spin cup 9. To be done.

Next, the high-pressure air blown by the air knife is once stopped, and then the substrate 6 before drying, on which a large amount of pure water 14 is deposited, is fixed on the substrate chuck 7. Then, the slide mechanism 4 and the vertical drive mechanism 5 move the air knife 1 and the exhaust pipe 2 to the position near the substrate shown by the solid line in FIG. Along with this, the blowing direction of the high-pressure air of the air knife 1 is tilted from directly below to the illustrated direction. Next, the flow rate of the high pressure air of the air knife is set to a level suitable for drying by the air knife (for example, 100 to 200 l described above).
/ Min). At the same time, the exhaust of the exhaust pipe 2 is started. The slide mechanism 4 moves the air knife 1 and the exhaust pipe 2 to the left in FIG. 5, and the pure water removal and drying on the substrate is executed by the air knife. Since the subsequent drying by the air knife is basically the same as that described in the first embodiment, the detailed description thereof will be omitted. However, compared with the case of the first embodiment of FIG. 1, since three sets of the air knife 1 and the exhaust pipe 2 are provided, the horizontal movement distance by the slide mechanism is short, and the drying time by the air knife is short. Can be shortened. Alternatively, the air knife may be more completely dried by allowing the air knife to pass through the same portion of the substrate a plurality of times and performing the drying operation by the air knife a plurality of times for the same portion.

After the drying by the air knife 1 is completed, the blowing of the high pressure air is stopped. By the slide mechanism 4 and the up-and-down driving mechanism 5, the upper part of the enclosure 16 is returned to the position shown by the alternate long and short dash line in FIG. Then, similarly to the drying in the first embodiment, low speed rotation and high speed rotation are performed. After that, the dried substrate is transported to the outside of the drying chamber. Next, before the substrate to be dried is carried in, downflow is performed by the air knife 1 to clean the air around the substrate device. In the drying according to the second embodiment performed as described above, the number of particles around the substrate set position is extremely small due to the downflow by the air knife before drying, and the particles are not directly attached to the substrate during the drying. Since the splashing of pure water and the mist capturing particles and adhering them together are extremely reduced, the yield and quality can be improved in the subsequent steps. Although FIG. 5 shows a structure in which three sets of air knives and exhaust pipes are provided, the number thereof is not particularly limited.

FIG. 6 is a diagram showing the relationship between the drying sequence and the flow rate of high-pressure air from the air knife in the drying method using the drying device shown in FIG. Hereinafter, with reference to FIG.
The drying sequence will be described below. Sequence 1 Before setting the substrate to which pure water before drying adheres on the substrate chuck 7 of the rotary substrate drying device, a small flow rate, for example, 50 l / min of high-pressure air is blown from the air knife to down-flow the air in the enclosure plate 16. To do. This blowing time is preferably as long as possible before the start of the work for one day. Further, if it is carried out between the drying and the next drying, an appropriate time (this time is preferably longer, but is determined in consideration of the effect of downflow and work efficiency) may be used.

Sequence 2 Air knife drying After temporarily stopping the high-pressure air blow by the air knife, the substrate 6 with the pure water 14 attached thereto is set on the substrate chuck 7 of the rotary substrate dryer, and then the drive motor blows the air knife 1. The direction is rotated to form an angle of 45 degrees with respect to the surface of the substrate 6, and the slide mechanism 4 and the vertical drive mechanism 5 bring the outlet of the air knife 1 close to the vicinity of the surface of the substrate shown by the solid line in FIG. 150
1 / min of high-pressure air is blown out from the air knife 1, and at the same time, the exhaust pipe 2 starts to be exhausted, and the air knife 1 and the exhaust pipe 2
And are moved to the left in the figure to dry the surface of the substrate 6 to which the pure water 14 is attached. The sequence of low speed rotation and high speed rotation thereafter is basically the same as the substrate drying sequence by rotation described in the first embodiment. If the drying is performed in the above sequence using the rotary substrate drying device of the second embodiment having the structure shown in FIG.
Drying can be performed in a highly clean environment.

FIG. 7 is a partial schematic view showing a third embodiment of the drying apparatus of the present invention. As shown in FIG. 7, in the present embodiment, the high-pressure air outlet of the air knife 1 is always directed downward, and the exhaust pipes 2 are arranged on both sides of the air knife. When the air knife configured in this manner is used, the downflow of high-pressure air and the drying operation by the air knife can be performed without rotating the air knife, which simplifies the device and simplifies the external operation. It Further, when the operation of blowing high-pressure air to the center of the substrate by an air knife is also used during drying by high-speed rotation of the substrate (third drying process), it is preferable to blow the high-pressure air vertically, so that it is more efficient. Drying can be performed. Although only one set of the air knife and the exhaust pipe are shown in FIG. 7, a plurality of sets may be installed in parallel as in the second embodiment.

Although the preferred embodiments have been described above, the present invention is not limited to these embodiments, and appropriate modifications can be made within the scope of the claims. For example, the high-pressure gas ejected from the air knife may be an inert gas such as nitrogen gas instead of air.

[0025]

According to the present invention, since a large amount of pure water on the surface of the substrate is removed by the air knife before the spin drying treatment, the amount of pure water scattered from the substrate at low speed rotation can be reduced, and the spin cup can be reduced. It is possible to reduce splashes hitting and re-attaching to the substrate. Further, even after shifting to high-speed rotation, the amount of mist generated is small because there is almost no pure water on the substrate. Therefore, according to the present invention, it is possible to obtain a uniformly dried substrate with less adherence of pure water or mist. Furthermore, according to the embodiment in which the high-pressure air is down-flowed from the air knife, it is possible to reduce particles around the substrate setting position and prevent contamination on the substrate surface. Therefore, the yield in the subsequent process can be improved and the quality can be improved. Further, when the high-pressure gas is not blown to the center of the substrate during high-speed rotation drying, it is possible to prevent the constant flow of air flow generated during the rotation process from being disturbed, and to efficiently exhaust the gas. So
The removal of mist in the spin cup becomes more efficient, and reattachment of mist to the substrate can be prevented more effectively.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a rotary substrate drying apparatus of the present invention.

FIG. 2 is a plan view showing a first embodiment of a rotary substrate drying apparatus of the present invention.

FIG. 3 is a drying sequence showing a first embodiment of a rotary substrate drying method of the present invention.

FIG. 4 is a schematic diagram illustrating an air knife driving mechanism in a second embodiment of the rotary substrate drying apparatus of the present invention.

FIG. 5 is a sectional view showing a second embodiment of the rotary substrate drying apparatus of the present invention.

FIG. 6 is a diagram showing a drying sequence for explaining a second embodiment of the rotary substrate drying method of the present invention and a flow rate of high-pressure air from an air knife.

FIG. 7 is a partial schematic diagram of the third embodiment of the rotary substrate drying apparatus of the present invention.

FIG. 8 is a sectional view of a conventional general rotary substrate drying apparatus.

[Explanation of symbols]

1 air knife 2 exhaust pipe 3 exhaust hose 4 slide mechanism 5 Vertical drive mechanism 6 substrate 7 Substrate chuck 8 spin motors 9 spin cups 10 Anti-rebound ring 11 Current plate 12 drain 13 Exhaust port 14 Pure water 15 rotation axis 16 shroud 17 nozzles

Claims (13)

(57) [Claims] 1. A substrate chuck for holding a substrate horizontally,
A spin motor that rotates the substrate chuck about the center of the chuck, an air knife that can blow out high-pressure gas onto the substrate, and an air knife that is held in close proximity to the air knife and integrally blown from the air knife. A rotary substrate drying apparatus having an exhaust pipe for exhausting high-pressure gas. 2. A vertical movement mechanism for vertically moving the air knife and the exhaust pipe, and a horizontal movement mechanism for integrally moving the air knife and the exhaust pipe in the horizontal direction. The rotary substrate drying device according to claim 1. 3. The substrate chuck and the spin motor are arranged in a bottomed cylindrical spin cup that has a drainage port and an exhaust port and prevents the liquid from splashing from the substrate when the spin motor rotates. The rotary substrate drying device according to claim 1 or 2, wherein 4. The rotary substrate drying apparatus according to claim 1, wherein a plurality of sets of the air knife and the exhaust pipe are arranged in parallel. 5. The rotary substrate drying apparatus according to claim 1, further comprising a driving mechanism that changes a blowing direction of high-pressure gas from the air knife. 6. The drying apparatus according to claim 1, wherein at least the substrate chuck, the spin motor, the air knife, and the exhaust pipe are arranged in a closed drying chamber. Rotary substrate dryer. 7. (1) A high-pressure gas is blown onto the surface of the substrate from an air knife in the vicinity of the substrate while the substrate is stopped, and exhaust is performed by an exhaust pipe arranged in proximity to the air knife. A rotary substrate drying method comprising: a drying step; (2) a second drying step of rotating the substrate at a low speed; and (3) a third drying step of rotating the substrate at a high speed. 8. (1) A spin cup and the spin cup
In a drying chamber composed of a surrounding plate ,
High pressure gas is down-flowed by an air knife while exhausting to clean the atmosphere in the spin cup, (2) mounting a wet substrate in the spin cup, and (3) stopping the substrate. In this state, a high-pressure gas is blown onto the surface of the substrate from the air knife in the vicinity of the substrate and exhaust is performed by an exhaust pipe arranged in the vicinity of the air knife, and (4) the substrate is A rotary substrate drying method comprising: a second drying step of rotating at a low speed; and (5) a third drying step of rotating the substrate at a high speed. 9. The rotary substrate drying according to claim 7, wherein in the first drying process, the high-pressure gas is blown onto the substrate surface by the air knife with respect to the central portion of the substrate. Method. 10. The first drying process, wherein the high-pressure gas is blown onto the surface of the substrate by the air knife while moving the air knife and the exhaust pipe on the substrate. 7. The rotary substrate drying method according to 7 or 8. 11. The rotary substrate drying method according to claim 10, wherein the blowing of the high-pressure gas is repeated a plurality of times for at least a part of the substrate portion. 12. The air knife and the exhaust pipe stand by at a high place before the first drying process starts, and descend at the start of the first drying process, The method for drying a rotary substrate according to any one of claims 7 to 11, wherein the temperature rises after the completion of the drying process. 13. The rotary substrate according to claim 7, wherein the third drying process is performed while a high-pressure gas is blown onto the central portion of the substrate by the air knife. Drying method.