JP2909346B2 - Rotary coating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the application of a photoresist liquid or the like to the surface of a substrate (hereinafter simply referred to as "substrate") such as a glass substrate for a liquid crystal display panel, a semiconductor wafer, and a mask substrate for manufacturing semiconductor devices. The present invention relates to a rotary coating device for coating a liquid.

[0002]

2. Description of the Related Art Conventionally, as this kind of a rotary coating apparatus, there is one described in, for example, Japanese Patent Application Laid-Open No. 4-61555. FIG. 8 is a cross-sectional view showing a rotary coating apparatus described in the publication, and FIG. 9 is a partially enlarged view of the rotary coating apparatus shown in FIG. In this rotary coating apparatus, a rotary table 62 that rotates while supporting the substrate 60 horizontally is provided. On the turntable 62, substrate support pins 64 are provided upright, and engagement pins 66 are provided to engage with four corners of the substrate 60, and the substrate 60 is horizontally supported by the substrate support pins 64. 60 can be rotated integrally with the turntable 62.

An upper rotating plate 68 is disposed above the substrate 60 supported by the rotating table 62, and the upper supporting plate 7
0, a ring plate 72 and a spacer 74 are connected to the turntable 62. And, as shown in FIG.
A washer 76 is inserted between the ring plate 72 and the spacer 74 and between the spacer 74 and the turntable 62 to form a gap 78. Then, the substrate 60 is placed on the turntable 62, and the application liquid is dropped on the center of the upper surface of the substrate 60.
The coating liquid is diffused by rotating the turntable 62 with the substrate 60 mounted close to the upper surface, whereby a uniform thin film can be formed on the upper surface of the substrate 60.

At this time, when the turntable 62 is rotated while the substrate 60 is horizontally supported, as shown by a dotted line in FIG.
Excess coating liquid flows out through the gap 78 and scatters.

In the rotary coating apparatus shown in FIG. 8, a waste liquid collecting case 80 surrounding the turntable 62 is provided, and the coating liquid scattered from the gap 78 as described above is collected in the waste liquid collecting case 80. It is configured as follows.

[0006]

By the way, in the conventional rotary coating apparatus, as described above, the coating liquid is diffused on the upper surface of the substrate 60 by rotating the turntable 62, and a uniform thin film is formed on the upper surface of the substrate. While forming, the excess coating liquid flows out of the turntable 62 through the gap 78,
The waste liquid collection case 80 receives and collects the waste liquid.
At this time, the surplus application liquid from the gap 78 is scattered as a splash, and adheres to the inner surface of the waste liquid recovery case 80 and contaminates the surroundings. Depending on the degree of the scattering, it is difficult to wash away the scattered excess coating liquid with a cleaning liquid or the like, and the excess coating liquid is dried and solidified, and then becomes fine dust due to vibrations of the apparatus and the like. It drifts around 62 and adheres to the substrate 60 to cause problems such as lowering the yield.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a rotary coating apparatus capable of preventing or reducing the excess coating liquid from being scattered to the outside and contaminating the surroundings. The purpose is to provide.

[0008]

In order to achieve the above object, a rotary coating apparatus according to the present invention comprises a rotating table for rotating a substrate while horizontally supporting the substrate, and a predetermined distance from the substrate supported by the rotating table. An upper rotating plate arranged in parallel at an upper position separated by a spacer, and a spacer arranged between an outer peripheral portion of the turntable and an outer peripheral portion of the upper rotating plate, wherein the substrate is horizontally supported. In a rotary coating apparatus that applies a coating liquid on the upper surface of the substrate by rotating the same with a rotating table, the coating liquid is provided on the spacer, and the excess coating liquid scattered by the rotation of the substrate is stored by centrifugal force during rotation. wherein the trap portion, the trap portion opening provided in the lower portion as excess coating solution that is the reservoir flows out to the outside due to a decrease in centrifugal force, the excess coating liquid stored in the trap opening Induced in comprises an outlet guide member to facilitate its outflow, the.

[0009]

According to the present invention, the trap portion is provided on the spacer, and when the rotary table is rotated to apply a certain level of centrifugal force, excess coating liquid from the substrate is stored in the trap portion. Further, an opening is provided at a lower portion of the trap portion, and when the rotation of the turntable is decelerated and the centrifugal force becomes less than a certain value, the excess coating liquid stored in the trap portion is moved by the action of gravity. It is dropped from the opening and flows out. In addition , since the excess coating liquid is guided by the outflow guide member in the direction of the opening and is easily flown out , the excess coating liquid stored in the trap portion flows out to the outside in a short time.

[0010]

FIG. 1 is a sectional view showing an embodiment of a rotary coating apparatus according to the present invention. In this rotary coating apparatus, for example, a rotary table 6 on which a rectangular substrate 2 can be mounted and which is rotatable around a rotary shaft 4 is provided. That is,
A rotating shaft 8 is vertically provided along the rotating shaft 4, and a rotating table 6 is horizontally mounted to a top end of the rotating shaft via a connecting boss 10, and a motor (not shown) is connected to a lower end thereof. A plurality of substrate support pins 14 project from the upper surface of the turntable 6 to support the back surface of the substrate 2, and four sets of engaging pins 16 erected on the turntable 6 The substrate 2 is horizontally fixed by being engaged with the four corners (see FIG. 6). As described above, the turntable 6 can horizontally rotate around the rotation axis 4 while supporting the substrate 2 horizontally.

On the upper side of the turntable 6, an upper turn plate 18 is arranged in parallel with a substrate 2 supported on the turntable 6 at a predetermined distance above. As shown in FIG. 1, the upper rotary plate 18 is vertically movable by a lifting device (not shown). In this state, it rotates around the rotation axis 4.

FIGS. 2 and 3 are enlarged views of the spacer 20 of the rotary coating apparatus of FIG. As shown in both figures,
An annular spacer 20 is provided on the outer peripheral portion of the upper surface of the turntable 6, and the spacer 20 is connected to the turntable 6 by a connecting member (not shown) and attached thereto. An outflow path 48 for allowing excess coating liquid to flow out is formed. On the other hand, the upper rotating plate 18
Are detachably attached to the spacer 20 by the fitting of the pins P. When the upper rotating plate 18 is lowered and mounted on the spacer 20, the rotating table 6 and the upper rotating plate 18
The spacer 20 forms a closed space S for performing the coating process on the substrate 2.

The spacer 20 is formed with a tapered portion 20a having a shape of a truncated cone from the outer peripheral side of the upper surface to the outer peripheral surface thereof.
A trap portion 20 b having a trapezoidal cross section is provided in a ring shape at a position facing the outer peripheral opening of the trapezoid 8. This trap portion 20b is communicated with the closed space S via the outflow path 48, and as shown in FIG.
When the centrifugal force F is applied, excess coating liquid from the substrate 2 flows into the trap section 20b via the outflow path 48 and is stored in the trap section 20b. In addition, an inclined surface 20d that becomes lower toward the inside in the radial direction of the turntable 6 is formed below the trap portion 20b, and an opening 20c is formed between the lower end of the inclined surface 20d and the outer peripheral end of the turntable 6. Is provided.

Reference numeral 21 denotes an outflow guide member, which comprises an outflow guide pin 21a and a holding member 21b. The outflow guide pin 21a is lowered downward at a position where its vertical portion is close to the trap portion 20b of the opening 20c. It is supported by the holding member 21b so as to project toward it. Outflow guide pin 2
1a, when the rotation speed of the turntable 6 decreases as shown in FIG. 3 and the centrifugal force F becomes less than a certain value or becomes zero,
The coating liquid is guided in the direction of the opening 20c so as to easily flow out by the surface tension with the coating liquid, and the flow is promoted.

FIG. 4 is a view showing a state of dripping of the coating liquid without the outflow guiding member 21. As shown in FIG. 4, the dripping speed from the opening 20c is reduced due to the surface tension of the coating liquid itself. It becomes slow and is not easily discharged. However,
By providing the outflow inducing member 21, the outflow operation of the coating liquid is greatly promoted as shown in FIG. 3, and it is possible to promptly shift to the next substrate coating step.

It is desirable that the lower end of the vertical portion of the outflow guide pin 21a protrudes below the opening surface of the opening 20c as shown in FIGS. 2 and 3, thereby effectively applying the coating liquid to the outside. Although it can be made to flow, it does not necessarily have to be projected depending on conditions such as the viscosity of the coating liquid.

FIG. 5 is a view showing a state in which the outflow guide member 21 is attached to the turntable 6. The holding member 21b of the outflow guide member 21 is fitted and fixed to the outflow guide member fixing notch 6a provided at a predetermined position in the periphery of the turntable 6. At this time, if the adhesive is applied to the notch 6a, the outflow guide member 21 can be more firmly fixed. In addition, the outflow guiding member 2 due to the high-speed rotation of the turntable 6
In order to prevent the projection 1 from jumping out, a projection for positioning is formed in the notch 6a, and a positioning hole for engaging with the projection for positioning is provided in one of the outflow guide members 21 so that both are fitted. You may make it attach it.

FIG. 6 is a view when the turntable 6 is viewed from above. As shown in the figure, four outflow guide members 21 are attached to the periphery of the turntable 6 symmetrically to the left and right to balance the weight, so that the rotation operation of the turntable 6 is not affected. ing. Of course, as the number of outflow guide members 21 increases, the effect of promoting the outflow of the coating liquid also increases. However, if at least one of the outflow guide members 21 is used, a certain effect of promoting outflow can be obtained.

Returning to FIG. 1, an annular cup 22 is arranged around the turntable 6. The cup 22 includes an inner cup 24 disposed below the outer periphery of the turntable 6 and an outer cup 26 disposed on the outer periphery of the turntable 6. In addition, a waste liquid outlet 28 for discharging waste liquid is provided at the bottom of the cup 22. Further, a space formed by the inner cup 24 and the outer cup 26 communicates with the exhaust port 30, and is configured to exhaust the solvent gas and the mist of the coating liquid evaporated from the coating liquid.

The rotary coating apparatus is provided with a back surface cleaning mechanism for cleaning the back surface of the substrate 2 and a cup cleaning mechanism for cleaning the inner surface of the cup 22.

In the back surface cleaning mechanism, a back surface cleaning nozzle 32 is mounted on the upper surface of the turntable 6 with its discharge port facing the back surface of the substrate 2, and the center of the rotary shaft 8 is connected via a connecting pipe 34. It is connected to a cleaning liquid supply pipe 36 that is inserted through the section and installed in a non-rotating state. The cleaning liquid supply pipe 36 is guided outside the rotary shaft 8 outside the figure, and is connected to a cleaning liquid supply source via an open / close valve (not shown). Then, when the opening / closing valve is opened, the cleaning liquid supplied through the cleaning liquid supply pipe 36 and the connection pipe 34 is jetted from the back surface cleaning nozzle 32 to the back surface of the substrate 2 to clean the back surface of the substrate 2.

On the other hand, the cup cleaning mechanism comprises an inner cup cleaning mechanism for cleaning the inner cup 24 and an outer cup cleaning mechanism for mainly cleaning the outer cup 26.

In the inner cup cleaning mechanism, an inner cup cleaning nozzle 38 is attached to the lower part of the outer periphery of the turntable 6. The inner cup cleaning nozzle 38 is disposed to face the inner surface of the inner cup 24 and is connected to the cleaning liquid supply pipe 36 via a connecting pipe 40 provided on the lower surface of the turntable 6. By opening the above-mentioned opening / closing valve, the cleaning liquid is also discharged from the inner cup cleaning nozzle 38 toward the inner surface of the inner cup 24 in synchronization with the discharge of the cleaning liquid from the back surface cleaning nozzle 32. I have. Thus, the inner cup 24 is washed by spraying the cleaning liquid from the inner cup washing nozzle 38 onto the inner cup 24.

In the outer cup cleaning mechanism, the outer cup cleaning nozzle 42 is attached to the outer cup 26 with its discharge port facing the tapered portion 20a of the spacer 20, as shown in FIG. . The outer cup cleaning nozzle 42 is connected to the above-described opening / closing valve and the cleaning liquid supply source via a connecting pipe 44, similarly to the back surface cleaning nozzle 32 and the inner cup cleaning nozzle 38. Then, by opening the above-mentioned opening / closing valve, the back surface cleaning nozzle 32.
In synchronization with the discharge of the cleaning liquid from the inner cup cleaning nozzle 38, the cleaning liquid is also supplied to the outer cup cleaning nozzle 42,
The ink is discharged to the tapered portion 20a. Thus, the tapered portion 20a
The cleaning liquid discharged to the taper 20a is repelled by the tapered portion 20a, or receives the centrifugal force of the turntable 6 to appropriately rotate the tapered portion 20a.
From the outer cup 26 and the outer cup 26 is washed.

Next, the operation of the rotary coating apparatus configured as described above will be described. First, as shown by the dashed line in FIG. 1, the upper rotating plate 18 is lifted, the upper opening of the turntable 6 is largely opened, and the substrate 2 is connected to the substrate supporting pins 1.
The substrate is mounted horizontally on the rotary table 4 to complete the substrate setting on the turntable 6.

Subsequently, the coating liquid supply nozzle 46
Is moved to the center of the central opening as shown by the dashed line in FIG. Then, a predetermined amount of the coating liquid is dropped on the center of the upper surface of the substrate 2. Thus, the application liquid is supplied to the substrate 2.

Thereafter, after the coating liquid supply nozzle 46 is retracted to an appropriate place, the upper rotating plate 18 is lowered and mounted and fixed on the spacer 20 to complete the preparation for the spin coating. Then, a motor (not shown) is driven to drive the substrate 2
While horizontally supporting the rotating table 6, the spacer 20
And the upper rotary plate 18 is rotated at a high speed (rotational speed N = N3). Due to this rotation, the coating liquid on the substrate 2 is diffused outward and thinly applied on the upper surface of the substrate 2. At this time,
As shown by the dotted arrow in FIG. 2, a part of the coating liquid is stored as excess coating liquid in the gap between the turntable 6 and the spacer 20, that is, the outflow path 48, and stored in the trap portion 20b by the centrifugal force F. As described above, during the spin coating process, the surplus coating solution does not scatter around the rotating table 6 such as in the cup 22, and the cup 22 does not become significantly contaminated by the scattered surplus coating solution.

When the spin coating on the substrate 2 is completed,
The rotation of the turntable 6 is temporarily stopped. As a result, the centrifugal force F applied to the coating liquid becomes zero, and the coating liquid stored in the trap portion 20b is discharged from the outflow guiding member 2 as shown in FIG.
It is guided by one outflow guide pin 21a and flows out almost vertically from the opening 20c. As described above, since the surplus coating liquid flows out while the turntable 6 is stopped, the surplus coating liquid does not scatter around the turntable 6 such as in the cup 22 even when the coating liquid is discharged. The cup 22 is not significantly contaminated by the scattered excess coating solution. Here, the number of rotations of the turntable 6 is set to zero, but this is not an essential requirement, and a certain number of rotations can be allowed. That is, when the rotation speed of the turntable 6 is reduced to a certain rotation speed, the centrifugal force F becomes weaker,
The coating liquid in the trap portion 20b flows out from the opening 20c in a substantially vertical direction, and the same effect as described above can be obtained.

Next, the rotation speed N of the turntable 6 becomes the rotation speed N1.
(<N3), and a cleaning liquid for dissolving the coating liquid is supplied to each of the cleaning nozzles 32, 38, and 42 for a predetermined time, and the cleaning process is performed. That is, the back surface of the substrate 2 is cleaned by the cleaning liquid blown out from the back surface cleaning nozzle 32, the inner peripheral surface of the inner cup 24 is cleaned by the cleaning liquid from the inner cup cleaning nozzle 38, and at the same time, the outer cup cleaning nozzle The inner peripheral surface of the outer cup 26 is cleaned by the cleaning liquid discharged from the. At this time, the cleaning liquid for cleaning the back surface of the substrate 2 is also similar to the excess coating liquid described above.
Once stored in the trap section 20b.

Next, the rotation speed N of the turntable 6 is changed to the rotation speed N2.
(<N3,> N1), and the washing liquid attached to the turntable 6 is scattered toward the cup 22 by centrifugal force and removed. Thereafter, the rotation of the turntable 6 is stopped and the trap unit 2 is stopped.
After the washing liquid stored in the upper rotating plate 18 is discharged and the upper rotating plate 18 is moved upward (the dashed line in FIG. 1),
The substrate 2 on which the coating process has been completed is taken out of the turntable 6.

In this way, a series of operations are completed. When processing is to be performed continuously, the above-described operation cycle is repeated.

In the above embodiment, the trap section 20b has a trapezoidal cross section. However, the excess coating liquid generated during the spin coating process can be stored, and the rotation speed of the turntable 6 is constant. If it is less than the above, any shape may be used as long as it can flow out to the outside. For example, the cross section may have an arc shape.

Also, the trap portion 20b is provided so that at least the excess coating solution can be stored in the trap portion 20b.
The size of the coating liquid may be determined, but the coating liquid required in one coating step, that is, the coating liquid more than the amount supplied from the coating liquid supply nozzle 46 per one time can be stored. It is desirable.

In the above embodiment, the rotary table 6 is provided with the spacer 20 made of a member different from the rotary table 6, but in the present invention, the rotary table 6 and the spacer 20 are separated by a separate member. It is not necessary to configure, and the spacer may be formed integrally with the turntable, and a trap portion may be provided on such a turntable.

The outflow guide pin 2 of the outflow guide member 21
Various modified examples are also conceivable for the shape of 1a.
For example, in the embodiment of FIG. 2, the tip of the outflow guide pin 21a is formed flat, but if the tip 21c is rounded as shown in FIG. 7A, dripping of the application liquid is further promoted. be able to. Further, as shown in FIG. 7B, the horizontal portion of the outflow guide pin 21a is protruded to
forming a d, track the protrusion 21d is of the spacer 20
By contacting the coating liquid stored in the pump section 20b ,
The outflow guide of the application liquid by the outflow guide pins 21a becomes more effective.

Further, if the outflow guide pins 21a are formed in two branches as shown in FIGS. 7 (c) and 7 (d), the area of contact with the coating liquid increases, and the effect of inducing outflow can be further increased.

In the above-described embodiment, the outflow guide pin 21a is formed as the outflow guide portion of the outflow guide member 21, but instead of the pin-shaped member, a plate-shaped member or another shape is used. It may be installed vertically. However, if an excessively large member is attached, the area of the opening 20c may be reduced and the outflow effect may be hindered, and if a member having a complicated shape is attached, the coating liquid may dry and adhere to that portion, This must be kept in mind. Further, in the embodiment, the outflow guide member 21 is attached from the inner peripheral side toward the inside of the trap section 20b when viewed from the trap section 20b, but is not limited thereto, and may be attached to, for example, the outer peripheral side of the inner surface of the trap section 20b. .

[0038]

As described above, according to the present invention, the trap portion is provided on the spacer, and when the rotating table is rotated to apply a predetermined centrifugal force, the excess coating liquid from the substrate is stored in the trap portion. On the other hand, when the rotating table is decelerated or stopped and the centrifugal force becomes less than a certain value, the excess coating liquid stored in the trap portion is guided by the outflow guide member and an opening provided below the trap portion. Since it is designed to be quickly discharged to the outside from the part, it is possible to suppress the scattering of the excess coating solution, and as a result, to prevent contamination of the surrounding area,
In addition to the reduction, it is possible to promptly shift to the next substrate coating step.

[Brief description of the drawings]

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

FIG. 2 is a partially enlarged view of the rotary coating device of FIG.

FIG. 3 is a partially enlarged view of the rotary coating device of FIG. 1;

FIG. 4 is a view showing a state of an outflow of a coating liquid when no outflow guide member is provided.

FIG. 5 is a perspective view showing how the outflow guide member is attached to the turntable.

FIG. 6 is a plan view showing a mounting position of the outflow guide member on the turntable.

FIG. 7 is a view showing another embodiment of the outflow guide member.

FIG. 8 is a sectional view showing a conventional rotary coating apparatus.

FIG. 9 is a partially enlarged view of the rotary coating apparatus of FIG.

[Explanation of symbols]

 2 Substrate 4 Rotation shaft 6 Rotation table 18 Upper rotation plate 20 Spacer 20b Trap portion 20c Opening 21 Outflow guide member 21a Outflow guide pin S Closed space

Continuation of the front page (56) References JP-A-6-285413 (JP, A) JP-A-4-300673 (JP, A) JP-A-4-247265 (JP, A) JP-A-5-169003 (JP) , A) JP-A-4-17259 (JP, A) JP-A-6-126237 (JP, A) JP-A-4-61595 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB Name) B05C 7/00-21/00 G03F 7/16 502 H01L 21/027

Claims (1)

(57) [Claims] 1. A rotary table for rotating a substrate while horizontally supporting the substrate, an upper rotary plate arranged in parallel at an upper position at a predetermined distance from the substrate supported by the rotary table, and an outer peripheral portion of the rotary table And a spacer disposed between an outer peripheral portion of the upper rotating plate and a rotary coating for applying a coating liquid on the upper surface of the substrate by rotating the rotating table while horizontally supporting the substrate. In the apparatus, a trap unit provided on the spacer and storing the excess coating liquid scattered by the rotation of the substrate by centrifugal force during rotation, and the stored excess coating liquid flows out due to a decrease in centrifugal force. an opening provided in the trap portion lower as the excess coating liquid stored in the trap portion is guided to the opening, to comprising: the outflow guide member to facilitate its outflow, the Rotary coating equipment.