JPH10414A - Coating device - Google Patents

Abstract

(57) [Problem] To provide a coating apparatus capable of efficiently discharging a coating liquid stored in a storage section for surplus coating liquid. SOLUTION: This coating apparatus is provided outside a rotary table 2, a rotary table 2 supporting and rotating a substrate 1, an upper rotary plate 4 connected to the rotary table 2 via an outer peripheral ring 3. A storage section 5 for the excess coating liquid, a suction nozzle 6 for sucking and discharging the excess coating liquid from the storage section 5, and a coating liquid supply for supplying the coating liquid to the center of rotation of the substrate 1 supported by the turntable 2 and rotating. A nozzle 7. The storage part 5 is disposed outside the outer peripheral position of the upper rotary plate 4 and has a circular opening 23 above the upper part thereof.
The suction nozzle 6 is used to discharge excess coating liquid from the opening 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus and a coating method for coating a coating liquid such as a photoresist on the surface of a substrate such as a glass substrate for a liquid crystal display panel, a semiconductor wafer, and a mask substrate for manufacturing semiconductor elements. About.

[0002]

2. Description of the Related Art This type of coating apparatus supplies a coating liquid near the center of rotation on the surface of a substrate supported by a turntable, then rotates the substrate together with the turntable, and moves the coating liquid outward by centrifugal force. It is configured so as to spread uniformly and apply over the entire surface of the substrate. By providing an upper rotating plate that rotates with the turntable above the substrate, the film pressure of the application liquid applied to the substrate surface is made uniform.

In such a coating apparatus, an excess coating liquid of the coating liquid supplied to the surface of the substrate is scattered outward from an edge of the substrate as the substrate is rotated. For this reason,
A collection case is provided on the outer periphery of the turntable. Excess coating liquid scattered from the substrate (hereinafter referred to as “excess coating liquid”) is captured by the collection case and flows out from the lower end of the collection case to be collected. It is configured to be.

However, in such a device,
For example, when a resist for manufacturing a color filter for a liquid crystal display panel is used as a coating liquid, the resist is large and hardly soluble in a solvent and has low fluidity. It may be. If the coating solution is dried and solidified while adhering to the inside of the collection case, particles are generated due to vibrations of the apparatus and the like, and the particles adhere to the substrate to cause a problem such as a decrease in yield.

On the other hand, Japanese Patent Laid-Open Publication No. Hei 7-136572 discloses a method of collecting a surplus coating liquid in an inner peripheral portion of an inner cup composed of the above-mentioned rotary table, upper rotating plate and the like in order to recover the surplus coating liquid. There is disclosed a coating apparatus in which a nozzle for sucking and discharging the surplus coating liquid stored in the storage section is movably arranged while being provided.

[0006]

Problems to be Solved by the Invention Japanese Patent Laid-Open No. Hei 7-13657
In the coating apparatus described in Japanese Patent Application Publication No. 2 (1993) -1995, a recovery section for an excess coating liquid is provided on an inner peripheral portion of an inner cup including a rotating table, an upper rotating plate, and the like. Therefore, the collecting unit is located below the upper rotating plate, and in order to suck and discharge the excess coating liquid by the nozzle after the completion of the coating process on the substrate, once the upper rotating plate is opened, the upper rotating plate is opened. , The nozzle must be moved to enter the storage section from above the storage section to perform a suction / discharge operation of the excess coating liquid.

For this reason, the work of sucking and discharging the surplus coating solution can be executed only when the upper rotating plate is released. That is, in the coating apparatus described in Japanese Patent Application Laid-Open No. 7-136572, the coating liquid is stored in the storage unit not only at the time of spin coating of the coating liquid on the substrate but also at the time of the opening operation and the closing operation of the upper rotating plate. The operation of sucking and discharging the surplus coating liquid cannot be executed.

On the other hand, with the recent increase in the size of the substrate, a relatively long time may be required for suctioning and discharging the excess coating solution. In addition, when the upper rotary plate is opened and closed at a high speed, particles due to the application liquid and the like are generated, so that a certain time is required for the opening operation and the closing operation of the upper rotary plate. For this reason, in the coating device described in Japanese Patent Application Laid-Open No. 7-136572, it is impossible to perform the suction / discharge operation of the excess coating liquid stored in the storage unit when the upper rotating plate is opened and closed. Due to this, it becomes impossible to efficiently perform the operation of sucking and discharging the surplus coating liquid,
This causes a problem that the processing time of the entire coating apparatus becomes longer.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a coating apparatus capable of efficiently discharging an excess coating liquid stored in a storage section.

[0010]

According to a first aspect of the present invention, there is provided a rotary table for supporting a substrate and rotating about a vertical rotation axis, and a coating solution on a surface of the substrate supported by the rotary table. And an upper rotating plate disposed in parallel with the substrate supported by the turntable at an upper position at a predetermined distance from the substrate supported by the turntable, and surplus scattered from the rotating substrate supported by the turntable. In a coating apparatus having a storage unit that captures and stores a coating liquid and a suction nozzle that suctions and discharges excess coating liquid stored in the storage unit, the storage unit is configured such that an outer periphery of an upper rotating plate with respect to a rotation shaft is provided. It is provided outside the position, and an opening is formed in the upper part thereof, and the excess coating liquid is discharged from the opening by a suction nozzle.

According to a second aspect of the present invention, in the first aspect, a plurality of suction nozzles are provided outside the outer peripheral position of the upper rotary plate with respect to the rotary shaft.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the suction nozzle is provided with a discharge position for suctioning and discharging the surplus coating liquid by the suction nozzle, and a position above the discharge position. And an elevating means for elevating and lowering the evacuation position.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a coating apparatus according to a first embodiment of the present invention, and FIG. 2 is a partially enlarged sectional view of the coating apparatus.

This coating apparatus is for applying a coating liquid composed of a resist agent on the surface of a square glass substrate 1.
A rotating table 2 that supports and rotates the substrate 1, an upper rotating plate 4 that comes into contact with and separates from the rotating table 2 via an outer peripheral ring 3, and a surplus coating liquid reservoir 5 disposed outside the rotating table 2. A suction nozzle 6 for sucking and discharging the surplus coating liquid from the storage unit 5, a coating liquid supply nozzle 7 for supplying the coating liquid to the rotation center of the substrate 1 supported by the rotating table 2, and a rotating table 2. And an exterior cover 10 disposed so as to surround it.

The turntable 2 has a rotation shaft 8 connected to a motor (not shown) via a connection boss 12 and rotates about a vertical axis of the rotation shaft 8. A plurality of support pins 13 are erected on the upper surface of the turntable 2, and
Is supported on its lower surface by the support pins 13. A plurality of engaging pins 14 are provided upright at positions corresponding to the respective corners of the substrate 1 supported by the support pins 13, and the substrate 1 is fixed by engaging with the engaging pins. .
On the upper surface of the turntable 2, a cleaning liquid nozzle 15 for supplying the cleaning liquid to the rear surface of the substrate 1 supported by the support pins 13 to prevent the application liquid from adhering to the rear surface of the substrate 1 is provided. Has been established. This back surface cleaning nozzle 1
Numeral 5 is connected via a connection pipe 16 to a cleaning liquid supply pipe 17 disposed in the hollow portion of the rotating shaft 8.

The turntable 2 has a substantially circular shape in a plan view, and a storage portion 5 for a surplus coating liquid having a substantially circular shape is provided on an outer peripheral portion thereof. The storage section 5 is for capturing and storing excess coating liquid scattered from the surface of the substrate 1 by centrifugal force. As shown in FIG. 2, the storage section 5 has a wall 21 for capturing excess coating liquid. A concave portion 22 for storing the surplus coating liquid, and an opening portion 23 provided above the concave portion 22. The wall 21, the recess 22, and the opening 23 are formed in a circular shape around the rotation shaft 8.

An outer peripheral ring 3 is disposed above the storage section 5. The outer peripheral ring 3 has a substantially circular shape centered on the rotating shaft 8, similarly to the turntable 2 and the storage unit 5. The outer peripheral ring 3 is screwed to the storage part 5 via a spacer at a dozen or more locations on the circumference around the rotation shaft 8. For this reason, a plurality of gaps 24 are formed between the lower surface of the outer peripheral ring 3 and the surface of the storage section 5 facing the lower surface. Further, the inside of the outer peripheral ring 3 is an inclined surface 25 which becomes higher toward the inside in the radial direction of the turntable 2.

Above the outer peripheral ring 3, an upper rotating plate 4
Are installed in parallel with the substrate 1 supported by the turntable 2 at a predetermined interval. The upper rotating plate 4 is configured to be able to move up and down between a lowering position shown by a solid line and an uppering position shown by a dashed line in FIG. The upper rotating plate 4 is fitted with the outer peripheral ring 3 at the lowered position, and rotates about the rotating shaft 8 integrally with the rotating table 2 and the outer peripheral ring 3. In addition, as shown by a dashed line in FIG. 1, the application liquid supply nozzle 7 supplies the application liquid to the substrate 1 in a state where the upper rotating plate 4 is raised.

The suction nozzle 6 is connected to an air cylinder 27 via a connecting member 26. Thereby, the suction nozzle 6 moves up and down between the discharge position indicated by the solid line and the retracted position indicated by the two-dot chain line in FIG. Here, the discharge position is such that the tip end of the suction nozzle 6 is located at the opening 2 in the storage unit 5.
3 is a position where it is opposed to the lowermost end of the concave portion 22 at a slight distance after passing through, and the excess coating solution stored therein is sucked and discharged. The retracted position is a position where the tip of the suction nozzle 6 has moved above the upper surface of the storage unit 5. In addition, the suction nozzle 6 is connected to the drainage tank 3 that is set to a negative pressure by a suction pump 32 such as a vacuum pump.
3 is connected via an electromagnetic valve 34.

The exterior cover 10 is configured to cover the side and lower part of the turntable 2. An exhaust hole 28 connected to an exhaust device (not shown) is provided below the exterior cover 10, and mist and dust in the exterior cover 10 are discharged to the outside via the exhaust hole 28.

Next, the operation of the coating apparatus will be described.

First, as shown by a dashed line in FIG. 1, the upper rotating plate 4 is raised, and the substrate 1 transported by the transporting means (not shown) is placed on the support pins 13 of the rotating table 2.
Subsequently, as shown by a dashed line in FIG. 1, the application liquid supply nozzle 7 is moved to a position where the end thereof faces the center of the substrate 1 supported by the turntable 2, and then lowered to an appropriate height. Let it. Then, the coating liquid is dropped from the coating liquid supply nozzle 7 to the center of the surface of the substrate 1. When the dropping of the coating liquid is completed, the coating liquid supply nozzle 7 is retracted to a position where there is no problem in moving the upper rotary plate 4 up and down.

Subsequently, as shown by a solid line in FIG.
The upper rotating plate 4 is lowered to a position where its lower surface contacts the upper surface of the outer peripheral ring 3. Then, the turntable 2 is rotated together with the upper turntable 4 and the like at a rotation speed of, for example, about 1000 rpm. By this rotation, the coating liquid supplied to the surface of the substrate 1 spreads outward uniformly by centrifugal force, and a coating liquid layer on a thin film is formed on the entire surface of the substrate 1. In particular, in this embodiment, the substrate 1 is rotated in a semi-enclosed space formed by the turntable 2, the outer peripheral ring 3, and the upper rotary plate 4, so that the air flow generated on the surface of the substrate 1 causes the substrate 1 to rotate. It is possible to prevent the film pressure of the coating liquid from becoming uneven. In addition, if necessary, a cleaning liquid is supplied from the back surface cleaning nozzle 15 to the back surface of the substrate 1 in parallel with this coating process, thereby preventing the application liquid from adhering to the back surface of the substrate 1.

In this coating step, a part of the coating liquid supplied to the surface of the substrate 1 is scattered from the edge of the substrate 1 by centrifugal force and reaches the outer peripheral ring 3. Then, the surplus coating liquid moves outward along the inclined surface 25 of the outer peripheral ring 3 by the action of the centrifugal force, and passes through the gap 24 formed between the lower surface of the outer peripheral ring 3 and the surface of the storage section 5. Then, it is captured by the wall 21 of the storage unit 5 and stored in the recess 22.

In this embodiment, since the inclined surface 25 is formed especially on the inner side of the outer peripheral ring 3, the surplus coating liquid is guided along the inclined surface toward the gap 24 by the action of the centrifugal force. You. For this reason, it becomes possible to collect | recover excess coating liquid effectively. In this state, the suction nozzle 6 is waiting at the standby position. Therefore, the coating liquid that scatters through the gap 24 does not adhere to the suction nozzle 6.

In this embodiment, the gap 2
Reference numeral 4 functions as a communication part that connects the inside and the outside of the semi-enclosed space formed by the turntable 2, the outer peripheral ring 3, and the upper rotating plate 4. The wall 21 of the storage section 5 is arranged outside the gap 24, and the upper end of the wall 21 is arranged at a position sufficiently higher than the gap 24. For this reason, the surplus coating liquid that tends to scatter outside through the gap 24 is reliably captured by the wall 21 of the storage unit 5, and does not scatter outside from the storage unit 5. Note that the upper end of the wall 21 of the storage unit 5 only needs to be at least above the gap 24 that functions as a communication unit. Also,
Instead of the gap 24 provided between the lower surface of the outer peripheral ring 3 and the surface of the storage section 5, a plurality of openings may be provided in the outer peripheral ring 3 and these openings may function as communication parts.

When a thin film of the coating liquid is formed on the surface of the substrate 1 and the coating process is completed, the driving of the motor is stopped, and the turntable 2 rotating at a high speed is decelerated. When the rotation speed of the turntable 2 becomes, for example, about 20 rpm, the rotation speed is maintained in this state.

In this state, by lowering the suction nozzle 6 to the discharge position, the tip end of the suction nozzle 6 passes through the circumferential opening 23 in the storage section 5 and slightly differs from the lowermost end of the recess 22. Place them at a distance apart. Then, by opening the electromagnetic valve 34 provided between the drainage tank 33 in a negative pressure state and the suction nozzle 6 by the suction pump 32, the excess coating liquid stored in the concave portion 22 is suctioned, Collected in the drainage tank 33.

If the rotation speed of the turntable 2 in this discharging step is 20 rpm, the turntable rotates once in 3 seconds. Therefore, if the discharging operation is maintained for 3 seconds or more, the circumferential concave portion 2
2 can discharge all the surplus coating liquid. The higher the rotation speed of the turntable 2, the shorter the time required for the discharge operation can be. However, if the rotation speed is excessively high, the suction nozzle 6 does not hinder the suction operation of the excess coating liquid. Come. This rotation speed depends on the size of the substrate 1, the suction force of the suction nozzle 6, the viscosity of the surplus coating liquid, and the like, but is preferably about 5 rpm to 60 rpm.

In the coating apparatus according to this embodiment, since the storage section 5 is disposed outside the outer peripheral position of the upper rotary plate 4, the suction operation is performed only by moving the suction nozzle 6 up and down. It can be performed. Therefore, it is possible to omit a moving mechanism for moving the suction nozzle 6 to a position below the upper rotary plate 4 as in the related art, and to simplify the apparatus.

When the operation of discharging the surplus coating solution stored in the storage unit 5 by the suction nozzle 6 is completed, the rotation of the turntable 2 is stopped. Then, after the upper rotating plate 4 is lifted, the processed substrate 1 is carried out of the turntable 2 by a transport means (not shown), and the substrate 1 to be processed next is carried into the turntable 2.

In the above-described embodiment, since the excess coating liquid is sucked by the suction nozzle 6 while rotating the substrate 1 together with the turntable 2, the tip of the suction nozzle 6 slides with the recess 22. In order to prevent the generation of particles due to the movement, the excess coating liquid is sucked while the tip of the suction nozzle 6 is separated from the lowermost end of the recess 22 by a small distance. However, substrate 1
In the case where the excess coating liquid stored in the storage unit 5 is suctioned and discharged from one location by the suction nozzle 6 without rotating the suction nozzle 6, the tip of the suction nozzle 6 is connected to the lowermost end of the recess 22. The surplus coating liquid may be sucked in a state where it is in contact with the liquid.

At this time, the plane including the circular tip of the suction nozzle 6 forming the opening for sucking the excess coating liquid and the surface of the lowermost end of the recess 22 are parallel to each other.
In the case where the circular tip portion of the surface abuts on the lowermost surface of the concave portion 22 over its entire surface, the suction nozzle 6 cannot effectively suction the excess coating liquid stored in the concave portion 22. For this reason, by forming the tip of the suction nozzle 6 into a shape in which the tip is obliquely cut, the plane including the tip of the suction nozzle 6 and the surface of the lowermost end of the recess 22 are not parallel. It is preferable that a gap is formed between the tip of the suction nozzle 6 and the surface of the recess 22 so that the surplus coating liquid always passes.

In the above-described embodiment, a case has been described in which after the coating liquid application step is completed, the excessive coating liquid discharging step is executed without stopping the rotation of the substrate 1. After stopping, the substrate 1 may be rotated again at a low speed to discharge the excess coating liquid. That is, after the coating is performed on the rectangular substrate 1, the rotation of the substrate 1 is temporarily stopped, and then the substrate 1 is rotated by a predetermined angle to control the rotation angle position of the substrate 1. Although the substrate 1 is oriented in the direction, the substrate 1 may be rotated by one or more rotations when the rotation angle position of the substrate 1 is controlled to discharge the excess coating liquid.

Further, in the above-described embodiment, the case where the surplus coating liquid is discharged using a single suction nozzle 6 has been described. However, two suction nozzles 6 are disposed at positions 180 degrees apart from each other. Thus, the discharge efficiency may be doubled, and the time required for discharging the surplus coating liquid may be shortened. In this case, by rotating the turntable 2 at least 180 degrees, the excess coating liquid can be efficiently discharged from the entire area of the storage unit 5.

Next, another embodiment of the present invention will be described with reference to the drawings. 3 and 4 are sectional views of a coating apparatus according to a second embodiment of the present invention, FIG. 5 is a partially enlarged sectional view of the coating apparatus, and FIG. 6 is a schematic plan view of the coating apparatus. Note that the same members as those of the coating apparatus shown in FIGS. 1 and 2 are denoted by the same reference numerals.

This coating apparatus, like the coating apparatus shown in FIGS. 1 and 2, applies a coating liquid to the surface of a rectangular glass substrate 1. The rotating table 2 supports the substrate 1 and rotates.
An upper rotating plate 4 that comes into contact with and separates from the rotary table 2 via the outer peripheral ring 3, a surplus coating liquid storage section 5 disposed outside the rotary table 2, and a suction section for sucking the surplus coating liquid from the storage section 5. A plurality of suction nozzles 6 for discharging the liquid, a coating liquid supply nozzle 37 (see FIG. 4) for supplying a coating liquid from a slit-shaped discharge port 38 to the surface of the substrate 1 supported on the rotary table 2, and the rotary table 2. And an exterior cover 10 disposed so as to surround it.

The turntable 2 has a rotation shaft 8 connected to a motor (not shown) via a connection boss 12 and rotates about a vertical axis of the rotation shaft 8. An elevating shaft 39 that rotates in synchronization with the rotating shaft 8 and that performs an elevating operation by driving an elevating driving unit (not shown) is inserted into the rotating shaft 8. The part is provided with a vacuum chuck 42. The lower surface of the substrate 1 is suction-supported by the vacuum chuck 42 of the turntable 2,
It is moved up and down between the lowered position shown in FIG. 3 and the raised position shown in FIG.

The turntable 2 has a substantially circular shape in a plan view, and a storage portion 5 for a surplus coating liquid having a substantially circular shape is provided on an outer peripheral portion thereof, as shown in FIG. Have been. The storage section 5 is for capturing and storing excess coating liquid scattered from the surface of the substrate 1 by centrifugal force. As shown in FIG. 5, the storage section 5 includes a wall 21 for capturing the excess coating liquid. A concave portion 22 for storing the surplus coating liquid, and an opening portion 23 provided above the concave portion 22. The wall 21, the recess 22, and the opening 23 are formed in a circular shape around the rotation shaft 8.

An outer peripheral ring 3 is provided above the storage section 5. The outer peripheral ring 3 has a substantially circular shape centered on the rotating shaft 8, similarly to the turntable 2 and the storage unit 5. The outer peripheral ring 3 is screwed to the storage part 5 via a spacer at a dozen or more locations on the circumference around the rotation shaft 8. For this reason, a plurality of gaps 24 are formed between the lower surface of the outer peripheral ring 3 and the surface of the storage section 5 facing the lower surface. Further, the inside of the outer peripheral ring 3 is an inclined surface 25 which becomes higher toward the inside in the radial direction of the turntable 2.

Above the outer peripheral ring 3, an upper rotating plate 4
Are installed in parallel with the substrate 1 supported by the turntable 2 at a predetermined interval. The upper rotary plate 4 is configured to be able to move up and down between a lower position shown in FIG. 3 and an upper position shown in FIG. 4 by a lifting mechanism (not shown). The upper rotating plate 4 is fitted with the outer peripheral ring 3 at the lowered position, and rotates about the rotating shaft 8 integrally with the rotating table 2 and the outer peripheral ring 3.

As shown in FIG. 6, four suction nozzles 6 are arranged at equal intervals along the outer periphery of the storage section 5. Each of the suction nozzles 6 is connected to an air cylinder 27 via a connecting member 26 as in the embodiment shown in FIGS. 1 and 2. Thereby, each suction nozzle 6
Moves up and down between a discharge position shown by a solid line and a retreat position shown by a two-dot chain line in FIG. Here, the discharge position is
The distal end of the suction nozzle 6 passes through the opening 23 in the storage section 5 and faces the lowermost end of the recess 22 with a small distance therebetween, and sucks and discharges the excess coating liquid stored therein. Position. The retracted position is a position where the tip of the suction nozzle 6 has moved above the upper surface of the storage unit 5. Each of the suction nozzles 6 is provided with a drainage tank 33 that has been set to a negative pressure by a suction pump 32 such as a vacuum pump.
Are connected to each other via a solenoid valve 34.

The application liquid supply nozzle 37 is, for example,
As described in JP-A-284715, a coating liquid is applied to the surface of the substrate 1 from a slit-shaped discharge port 38. That is, the application liquid supply nozzle 37 is
As shown in FIG. 5, the discharge port 38 is provided so as to face the surface of the substrate 1 at the raised position. This outlet 38
Has a slit shape extending in a direction perpendicular to the plane of FIG. The coating liquid supply nozzle 37 is connected to moving means (not shown), and is configured to reciprocate in the left-right direction shown in FIG.

When the application liquid is supplied to the surface of the substrate 1 by the application liquid supply nozzle 37, the substrate 1 is supplied from the discharge port 38 while the application liquid supply nozzle 37 is moved by the moving means.
By discharging the coating liquid on the surface of the substrate 1, the coating liquid can be efficiently supplied to a predetermined range on the surface of the substrate 1.

The outer cover 10 is configured to cover the side and lower part of the turntable 2. An exhaust hole 28 connected to an exhaust device (not shown) is provided below the exterior cover 10, and mist and dust in the exterior cover 10 are discharged to the outside via the exhaust hole 28.

Next, the operation of the coating apparatus will be described.

First, the upper rotating plate 4 is raised as shown in FIG. Then, after moving the vacuum chuck 42 of the turntable 2 to the raised position, the substrate 1 transported by the substrate transport means (not shown) is suction-supported by the vacuum chuck 42.

Subsequently, the application liquid supply nozzle 37 is moved in parallel to the side from the position shown by the dashed line in FIG. 4, and the application liquid is discharged from the discharge port 38. This allows
The coating liquid is supplied to a predetermined area on the surface of the substrate 1. When the supply of the coating liquid is completed, the coating liquid supply nozzle 37 is retracted to a position where there is no problem in moving the upper rotary plate 4 up and down.

Subsequently, as shown in FIG. 3, the vacuum chuck 42 is lowered together with the substrate 1 to a lowered position. Further, the upper rotating plate 4 is lowered to a position where the lower surface of the upper rotating plate 4 contacts the upper surface of the outer peripheral ring 3. Then, the rotary table 2 and the vacuum chuck 42 are moved together with the upper rotary plate 4 and the like, for example, at 1000 r.
It is rotated at a rotation speed of about pm. By this rotation, the coating liquid supplied to the surface of the substrate 1 spreads outward uniformly by centrifugal force, and a coating liquid layer on a thin film is formed on the entire surface of the substrate 1. Particularly, in this embodiment, the substrate 1 is divided into a turntable 2, an outer ring 3 and an upper turntable 4.
Thus, the film pressure of the coating liquid can be prevented from becoming non-uniform due to the flow of air or the like generated on the surface of the substrate 1.

In this coating step, a part of the coating liquid supplied to the surface of the substrate 1 is scattered from the edge of the substrate 1 by centrifugal force and reaches the outer peripheral ring 3. Then, the surplus coating liquid moves outward along the inclined surface 25 of the outer peripheral ring 3 by the action of the centrifugal force, and passes through the gap 24 formed between the lower surface of the outer peripheral ring 3 and the surface of the storage section 5. Then, it is captured by the wall 21 of the storage unit 5 and stored in the recess 22.

In this embodiment, since the inclined surface 25 is formed particularly on the inner side of the outer peripheral ring 3, the surplus coating liquid is guided along the inclined surface toward the gap 24 by the action of the centrifugal force. You. For this reason, it becomes possible to collect | recover excess coating liquid effectively. In this state, the four suction nozzles 6 are waiting at the standby position. Therefore, the coating liquid that scatters through the gap 24 does not adhere to the suction nozzle 6.

In this embodiment, the gap 2
Reference numeral 4 functions as a communication part that connects the inside and the outside of the semi-enclosed space formed by the turntable 2, the outer peripheral ring 3, and the upper rotating plate 4. The wall 21 of the storage unit 5 is arranged outside the gap 24, and the upper end of the wall 21 is arranged at a position sufficiently higher than the gap 24. For this reason, the surplus coating liquid that tends to scatter outside through the gap 24 is surely captured by the wall 21 of the storage unit 5 and does not scatter outside from the storage unit 5. Note that the upper end of the wall 21 of the storage unit 5 only needs to be at least above the gap 24 that functions as a communication unit. Also,
Instead of the gap 24 provided between the lower surface of the outer peripheral ring 3 and the surface of the storage section 5, a plurality of openings may be provided in the outer peripheral ring 3 and these openings may function as communication parts.

When a thin film of the coating solution is formed on the surface of the substrate 1 and the coating process is completed, the rotation of the turntable 2 is stopped.
Then, by lowering the four suction nozzles 6 to the discharge position, the tip end of each suction nozzle 6 passes through the circumferential opening 23 in the storage unit 5 and is slightly away from the lowermost end of the recess 22. Placed at a distance from each other. And
By opening a solenoid valve 34 provided between the drainage tank 33 in a negative pressure state and the suction nozzle 6 by the suction pump 32, the excess coating liquid stored in the concave portion 22 is suctioned and drained. Collected in tank 33.

At this time, since the surplus coating liquid stored in the circumferential concave portion 22 is suctioned and removed by the four suction nozzles 6 arranged at equal intervals, even when the rotation of the turntable 2 is stopped. In addition, the excess coating liquid stored in the entire area of the concave portion 22 can be efficiently removed by suction.

The upper rotating plate 4 is raised in parallel with the operation of suctioning and removing the excess coating liquid by the suction nozzle 6. And
The processed substrate 1 is transferred to the turntable 2 by a transport means (not shown).
The substrate 1 to be processed next is transported from the turntable 2
Carry in.

In this embodiment, since the suction nozzle 6 sucks the excess coating liquid stored in the concave portion 22 while the rotation of the turntable 2 is stopped, the suction nozzle 6 The surplus coating liquid may be sucked in a state in which the leading end portion is in contact with the lowermost end portion of the concave portion 22. In this case, as in the case of the first embodiment described above, the tip of the suction nozzle 6 is formed into a shape in which the tip is obliquely cut, so that the flat surface including the tip of the suction nozzle 6 and the concave portion are formed. 22 is not parallel to the lowermost surface, and between the tip of the suction nozzle 6 and the surface of the recess 22,
It is preferable to always form a gap through which the surplus coating solution passes.

In the coating apparatus according to this embodiment, the operation of sucking and removing the excess coating liquid by the suction nozzle 6 and the operation of carrying in and out the substrate 1 including the operation of opening and closing the upper rotary plate 4 can be performed in parallel. It becomes possible. For this reason, it is possible to shorten the entire processing time including the discharge of the excess coating liquid.

Further, in the coating apparatus according to this embodiment, since the storage section 5 is disposed outside the outer peripheral position of the upper rotary plate 4, the suction operation is performed only by moving the suction nozzle 6 up and down. It can be performed. Therefore, it is possible to omit a moving mechanism for moving the suction nozzle 6 to a position below the upper rotary plate 4 as in the related art, and to simplify the apparatus.

Next, still another embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a schematic plan view of a coating apparatus according to a third embodiment of the present invention. The same members as those in the coating apparatus shown in FIGS. 1 to 6 are denoted by the same reference numerals.

In the above-described second embodiment, the surplus coating liquid is stored in the circumferential concave portion 22 provided in the circumferential storing portion 5 centered on the rotating shaft 8. In the coating apparatus according to the third embodiment, the surplus coating liquid is stored in four concave portions 45 provided at positions corresponding to the four suction nozzles 6.

The recess 45 is provided only at a position on the turntable 2 facing the corner of the substrate 1 sucked and supported by the vacuum chuck 42 (ie, substantially on a diagonal line of the substrate 1). The suction nozzles 6 are provided at positions corresponding to the four concave portions 45, respectively.
Further, in the first and second embodiments described above, the gap 24 is provided between the lower surface of the outer peripheral ring 3 and the surface of the storage portion 5 and functions as a communication portion. In the case of FIG.
, Four communication holes 46 are formed at positions facing the recess 45, and the communication holes 46 function as communication portions.

In the third embodiment, the surplus coating liquid scattered from the edge of the substrate 1 or the like by the centrifugal force in the coating step is converted into the inclined surface 25 of the outer peripheral ring 3 by the action of the centrifugal force.
Along the outer side, passes through four communication holes 46 formed in the outer peripheral ring 3, is captured by the wall 21 of the storage unit 5, and is stored in the four recesses 45.

In the coating apparatus according to the third embodiment, the surplus coating liquid scattered from the edge of the substrate 1 to the entire area of the outer peripheral ring 3 is provided at a position corresponding to the four suction nozzles 6. Since the liquid is stored in the concave portion 45, the operation of sucking and discharging the surplus coating liquid by the suction nozzle 6 can be performed more efficiently.

Further, in this embodiment, in particular, since the surplus coating liquid tends to be finally separated from the substrate 1 at a position where the surplus coating liquid is scattered most, the position opposing the corner of the substrate 1 is the largest. Since the communication hole 46 and the concave portion 45 are arranged, the operation of storing the surplus coating liquid in the concave portion 45 can be performed more effectively.

In the first and second embodiments, the tip of the suction nozzle 6 is not in contact with the lowermost end of the recess 22, and the tip of the suction nozzle 6 is separated from the lowermost end of the recess 22. In the case where the excess coating liquid is sucked, the vertical mechanism of the suction nozzle 6 may be omitted and the suction nozzle 6 may be always fixed at the suction position.

In the first, second and third embodiments, the case where the excess coating liquid discharged from the storage section 5 by the suction nozzle 6 is discharged to the drain tank 33 has been described. When an expensive coating liquid is used, the excess coating liquid collected by the suction nozzle 6 may be reused. In that case,
The supply of the cleaning liquid from the cleaning liquid supply pipe 17 in FIG. 1 to the back side of the substrate 1 is not performed.

[0067]

According to the first aspect of the present invention, the storage portion is disposed outside the outer peripheral position of the upper rotating plate with respect to the rotating shaft, and suction is performed from the opening formed in the upper portion of the storage portion. Since the excess coating liquid is discharged by the nozzle, the excess coating liquid can be discharged immediately when necessary, regardless of the state of the upper rotating plate. Therefore, it is possible to shorten the entire processing time including the discharge of the excess coating liquid.

According to the second aspect of the present invention, since a plurality of suction nozzles are disposed outside the outer peripheral position of the upper rotating plate with respect to the rotating shaft, the excess coating liquid is discharged more efficiently. It becomes possible.

According to the third aspect of the present invention, since the suction nozzle moves up and down between the discharge position and the retracted position, the suction nozzle is evacuated to the retracted position in the coating step, so that the nozzle is scattered from the substrate. It is possible to prevent the surplus coating liquid from adhering to the suction nozzle.

[Brief description of the drawings]

FIG. 1 is a sectional view of a coating apparatus according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the coating apparatus according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a coating apparatus according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a coating apparatus according to a second embodiment of the present invention.

FIG. 5 is a partially enlarged sectional view of a coating apparatus according to a second embodiment of the present invention.

FIG. 6 is a schematic plan view of a coating apparatus according to a second embodiment of the present invention.

FIG. 7 is a schematic plan view of a coating apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Rotating table 3 Outer ring 4 Upper rotating plate 5 Reservoir 6 Suction nozzle 7 Coating liquid supply nozzle 8 Rotating shaft 13 Support pin 14 Engagement pin 21 Wall 22 Recess 23 Opening 24 Gap 25 Slope 26 Connecting tool 27 Air cylinder 33 Waste liquid tank 32 Suction pump 37 Coating liquid supply nozzle 38 Discharge port 39 Elevating shaft 42 Vacuum chuck 45 Recess 46 Communication hole

Continued on the front page (72) Inventor Kazuo Kise 1 at 480 Takamiyacho, Hikone City, Shiga Prefecture Dainippon Screen Mfg. Co., Ltd.

Claims (3)

[Claims] 1. A rotary table for supporting a substrate and rotating about a rotation axis oriented in a vertical direction, supply means for supplying a coating liquid to a surface of the substrate supported by the rotary table, and a support for the rotary table. An upper rotating plate disposed in parallel with the substrate at an upper position separated by a predetermined distance from the substrate, and a storage unit that captures and stores excess coating liquid scattered from the rotating substrate supported by the rotating table. And a suction nozzle that suctions and discharges excess coating liquid stored in the storage unit, wherein the storage unit is disposed outside an outer peripheral position of the upper rotating plate with respect to the rotation shaft. And an opening formed in an upper portion of the coating device, and discharging the excess coating liquid from the opening by the suction nozzle. 2. The coating apparatus according to claim 1, wherein a plurality of the suction nozzles are arranged outside an outer peripheral position of the upper rotating plate with respect to the rotation shaft. 3. The coating apparatus according to claim 1, wherein the suction nozzle is configured to discharge a surplus coating solution by the suction nozzle and discharge the surplus coating liquid, and a retreat position above the discharge position. A coating device further comprising a lifting means for raising and lowering between the two.