JPH08103715A - Rotary application method and device - Google Patents

Abstract

PURPOSE: To enable the same thickness coating uniformly, as that obtained by a conventional coating method, using about half the quantity of a coating material consumed by the conventional method by dripping the coating material in the center of a rectangular substrate, then setting the shape in a rectangle which rotates from the center of the substrate, and rotating the substrate. CONSTITUTION: A rectangular glass substrate 1 is mounted on a vacuum chuck 6 in a skin cup 5 in a manner that the short side of the rectangle and the long side of a nozzle 2 forms 90 deg.. In addition, a nozzle arm 3 is moved horizontally to one side so that the center of the nozzle 2 passes through the center of the glass substrate 1. Further, a slit-like discharge orifice 4 is opened at the bottom of the nozzle 2 and a coating liquid is allowed to drip from the orifice. Next, the coating material is allowed to drip in the center of the glass substrate 1 in a rectangular form which is turned 90 deg. from the center. After that, the coating material is applied on the entire surface of the glass substrate 1 by rotating it. Then it is possible to realize the coat of the same thickness as that obtained by a conventional coating method using about half the quantity of the coating material consumed by the conventional method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method of a color filter for a color liquid crystal display device using a photoresist method or a shadow mask for a color picture tube using a photo etching method, and more particularly to a rectangular glass. The present invention relates to a device of a spin coating means used as a means for coating a coating material with a uniform film thickness on a substrate such as a plate or a metal plate.

[0002]

2. Description of the Related Art Conventionally, for example, as represented by the manufacture of a color filter for color liquid crystal display using a photoresist method, a coating material such as a photosensitive resin is applied to a rectangular substrate having a uniform coating film thickness, For example, it was necessary to apply it on a glass substrate.

A roll coating method or a spin coating method is generally known as a coating means therefor. However, in the roll coating method, the coating material is applied onto the substrate through a rotating roll, and therefore the substrate may be applied to the substrate after each application due to factors such as the gap between the roll and the substrate, the surface tension of the coating material, or the rotation speed of the roll. The coating thickness of the coating is different, or uneven streaks occur in the coating thickness on the same substrate.
There was a problem with coating quality.

Therefore, at present, the spin coating method, that is, the spin coating method is becoming the mainstream. In the spin coating method, conventionally, the coating material is dropped onto the substrate from the coating material discharge port located above the center of the substrate. As a result, the coating material 9 dropped as shown in FIG. 7 is dropped in a circular shape at the center of the substrate 1. After that, a centrifugal force is generated by rotating the substrate, and the applied material is spread by the force, and the application is performed.

The above-mentioned spin coating method is an effective means for achieving a uniform coating film thickness of the coating material on the substrate, but presently has the following problems. That is, by the rotation of the substrate, the dropped coating material is spread and spread on the substrate, but since the excess coating material that exceeds the amount that is adhered and coated on the substrate is shaken off from the substrate, The problem is that most of it becomes waste liquid.

Conventionally, in the spin coating method, because of the development by centrifugal force, an extremely large amount of coating material has to be dropped than the required coating amount. Therefore, usually about 90% of the dropped coating material was a waste liquid as an excess after spin coating.

Therefore, for example, in the production of a pigment dispersion type color filter for color liquid crystal display, the coating material used is an expensive resin in which a pigment is dispersed in a photosensitive resin, and It can be said that a large amount of coating material is required every time a color filter is manufactured, and most of the coating material is a waste liquid as it is, which is one of the causes of increasing the manufacturing cost of the color filter.

Further, in the future, color filters, shadow masks, and the like will gradually increase in size. for that reason,
The required substrate also becomes large, and the following problems are occurring in the conventional spin coating method. That is, the coating material dropped on the substrate has a circular shape, and the coating material is spread concentrically on the substrate by the same centrifugal force in all directions due to the rotation of the substrate. Therefore, when the size of the substrate is increased, the difference in angular rotation speed between the central portion and the peripheral portion of the substrate is larger than that in the conventional case, and the centrifugal force between the central portion and the peripheral portion of the substrate is larger than that in the conventional case. As a result, in the conventional spin coating method using a large amount of coating material, for example, the coating film thickness is large in the central portion of the substrate,
The problem is that coating defects are likely to occur on the side of the substrate such that the coating film thickness is different, such as the coating film thickness being thin.

[0009]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a method of rotating a coating material on a rectangular substrate, which is represented by, for example, a manufacturing process of a color filter used in a color liquid crystal display device. The object of the present invention is to provide a means for spin coating which does not cause the above-mentioned drawbacks during coating.

[0010]

That is, the present invention provides a spin coating method used as a means for coating a coating material with a uniform film thickness on a substrate such as a rectangular glass plate or a metal plate. The shape of the coating material dropped onto the central portion of the rectangular substrate is a substantially rectangular shape rotated by about 90 ° in the substrate rotation direction based on the substrate center, and then the substrate is rotated to apply the coating material. And a substrate rotating means for mounting and fixing a rectangular substrate, a coating material supplying means for supplying a coating material to a nozzle, and a nozzle being moved up and down to be retracted and approached from the rotating means. The nozzle arm and the nozzle have a substantially rectangular slit-shaped coating material discharge port, and the discharge port is moved in parallel with the long side of the discharge port and the long side of the substrate and the short side of the substrate. do it, To provide a spin coating device characterized in that it is provided with a dropping means for dropping a coating material onto a central portion of a plate in a substantially rectangular shape rotated by about 90 ° in the substrate rotation direction based on the substrate center. This is to solve the above problems.

The present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a spin coating device in the production of a color filter used in a color liquid crystal display device using the present invention.

In FIG. 1, the glass substrate 1 is transported to and placed on a vacuum chuck 6 in a spin cup 5 after cleaning the substrate surface and the like in the previous step. Note that the glass substrate 1 and the vacuum chuck 6 are brought into close contact with each other by vacuum suction. Further, the vacuum chuck 6 is rotated by a motor 10, and the glass substrate 1 placed on the vacuum chuck 6 is conveyed so that the center of the substrate and the center of the rotation axis coincide with each other.

Next, the nozzle arm 3 provided with the rectangular nozzle 2 is used as needed when the glass substrate 1 is conveyed, the coating material 9 is dropped on the glass substrate 1, or the glass substrate 1 is rotated. It can be moved vertically and horizontally by the driving device 11. Next, the coating material 9 such as the photosensitive resin in the tank 8 is supplied to the nozzle 2 through the tube 7 by pressurizing the tank 8 by the pressurizing device 12, and the nozzle 2 shown in FIG. It is dripped onto the glass substrate 1 from the coating material discharge port 4.

Next, FIG. 2 shows a part of FIG. 1 seen from above. As shown in FIG. 2, the rectangular glass substrate 1 is placed on the vacuum chuck 6 at the time of loading so that the short side of the substrate 1 and the long side of the rectangular nozzle 2 form an angle of 90 °. Further, as shown by the arrow in FIG. 2, the nozzle arm 3 with the nozzle 2 can be horizontally moved in the left and right directions, and when the nozzle arm 3 is horizontally moved, the center of the nozzle 2 is set to the center of the glass substrate 1. It is supposed to pass.

Next, FIG. 3 shows a view of the tip of the nozzle arm 3 with the nozzle 2 of FIG. 2 as seen from below.
As shown in FIG. 3, a slit-shaped coating material discharge port 4 is opened in the nozzle 2, and the coating material 9 is dropped onto the glass substrate 1 from the coating material discharge port 4. The nozzle 2 is removable, and the size of the coating material discharge port 4 can be changed by replacing the nozzle 2 in accordance with the size of the glass substrate 1.

The slit shape of the coating material discharge port 4 is preferably rectangular or elliptical because the coating material is dripped in a substantially rectangular shape. Further, the aspect ratio and size of the slit shape are preferably set appropriately depending on the process because there are various conditions such as the material of the coating material used, the number of rotations, the substrate size and the coating amount. For example, in the examples described later, by actually dropping the vertical and horizontal ratios of the slits, it is easy to control the discharge amount of the coating material at the start of dropping, and the cutting of the coating material at the end of dropping is good. Therefore, it was empirically found that a rectangular shape having an aspect ratio of 1:10 or more is desirable.

In the spin coating apparatus of the present invention, under the above conditions, as shown in FIG. 4, the long side of the substrate 1 and the long side of the coating material discharge port 4 are kept parallel to each other, and at the dropping start position D. The coating material discharge port 4 attached to the nozzle arm 3 starts dropping the coating material 9 onto the glass substrate 1, and further the coating material discharge port 4
Moves on the center of the substrate 1 in parallel with the short side of the substrate 1 while dropping, and ends the dropping at the dropping end position E, thereby rotating about 90 ° in the substrate rotation direction based on the center of the substrate. The coating material 9 is dropped onto the central portion of the glass substrate 1 in a substantially rectangular shape. Then, the glass substrate 1 on which the coating material 9 is placed is rotated by the motor 10 to spin-coat the coating material 9 on the entire surface of the glass substrate 1.

Here, the angle of about 90 ° is 45.
It means an angle in the range of up to 90 °, and when the angle exceeds the above range, the coating amount becomes large or coating failure easily occurs as shown in an example of FIG. 6 described later. It was empirically calculated for the reasons such as the above.

Next, referring to FIG. 5, the coating material 9 is dropped on the substrate 1 according to the conditions of the present invention, that is, when the glass substrate 1 is rotated by dropping a substantially rectangular shape rotated by 90 ° about the substrate center. The movement of the material 9 will be described.

When the glass substrate 1 is rotated, the following two forces are mainly exerted on the substrate 1. That is, as shown in FIG. 5A, the centrifugal force A due to rotation and the inertial moment B of the coating material 9 are two forces, and the coating material 9 is a vector combination of the centrifugal force and the inertial moment. The combined force C acts on the coating material.

Therefore, during the rotation of the substrate 1, the coating material 9 spreads, for example, in the side direction of the substrate 1, that is, outside, as shown in FIG. 5B, and also in the direction opposite to the rotating direction of the coating material 9. It will spread out in a figure eight shape.
Further, by continuing the rotation, as shown in FIG. 5C, the coating material 9 is sequentially spread from the long side to the short side of the substrate 1. The conditions for making the coating material dropped on the substrate into a rectangular shape similar to the substrate are empirically obtained as conditions suitable for reducing the coating amount by actually changing the dropping shape and performing spin coating. It was

Next, for the purpose of comparison with the present invention, when a dropping method different from the coating method of the present invention is performed, for example, as shown in FIG.
Rotate the dropping shape of the present invention by 90 ° as shown in (a),
Consider a case where the long-side of the coating material 9 and the long-side of the substrate 1 are parallel to each other and the dropping is performed and the spin-coating is performed.

In this case, as described above, the coating material 9 is
While spreading in the side direction of the substrate 1, that is, outward, it also spreads in a figure 8 shape in the direction opposite to the rotation direction of the coating material 9. As a result, by continuing the spin coating,
For example, as shown by the hatched portion in FIG. 6B, the coating material 9 largely protrudes from the substrate 1, and a larger amount of coating material is required than the coating method according to the drop shape of the present invention shown in FIG. That is clear. Also, for example, in FIG.
Due to the long distance from point F in point (b) to point G in the substrate angle, the coating material is not sufficiently spread. It may occur easily.

[0024]

By using the spin coating apparatus according to the present invention, it is possible to reduce the amount of coating material used as compared with the conventional spin coating method. Further, even when the size of the substrate is increased, a small coating amount is required, so that it is possible to prevent a coating defect such as the conventional method in which the coating film thickness is partially uneven.

Further, in the present invention, the scattering of the coating material to the outside of the substrate is smaller than that of the conventional one, so that the scattered coating material caused by the conventionally generated coating material scattered to the outside of the substrate is reattached to the substrate. This also reduces the contamination of the substrate.

[0026]

EXAMPLE An example in which the spin coating according to the present invention is applied to, for example, a color filter used in a color liquid crystal display device will be described below. <Example> First, a light shielding layer having a lattice pattern of metal chromium is formed on a glass substrate having a thickness of 1.1 mm and a size of 320 × 400 mm by a known method, for example, a method of etching after depositing metal chromium. Formed.

Next, using the spin coating apparatus shown in FIG. 1 according to the present invention, a photosensitive resin having a viscosity of 12 cps at room temperature of 23 ° C. and a close similarity to the substrate rotated 90 ° about the substrate center as shown in FIG. In a substantially rectangular shape, 13 ml was dropped on a glass substrate. In addition, the aspect ratio of the slit which is the coating material discharge port at that time was 1:10.

Then, the glass substrate is spin-coated at a rotation speed of 1000 rpm to give a film thickness of 1.
A photosensitive resin layer having a thickness of 5 μm was formed.

<Comparative Example> Next, the following steps were performed for comparison with the present invention. That is, with a thickness of 1.1 mm, 320
After forming a light-shielding layer having a grid pattern of metallic chrome on a glass substrate having a size of × 400 mm by the same method as described above,
Viscosity of 12c at room temperature 23 ° C using a conventional spin coater
A photosensitive resin of ps was dropped on the glass substrate in a circular shape as shown in FIG. Thereafter, spin coating was performed at a rotation speed of 1000 rpm, and 25 ml of the photosensitive resin was used to form a photosensitive resin layer having a thickness of 1.5 μm on the glass substrate as in the example. Needed.

Next, the coated surface of the glass substrate coated in the above example was checked. The coated film thickness was different each time it was coated on the substrate, or the coated film thickness was partially uneven on the same substrate. There was no problem such as the occurrence of uneven streaks, and a coating quality comparable to that of the conventional method was obtained.

[0031]

By using the spin coating apparatus according to the present invention, the amount of coating material used can be reduced as compared with the conventional spin coating method. For example, in the present embodiment, the coating material which required 25 ml in the conventional method is 1 in the present invention.
It was possible to obtain the same coating film thickness as in the conventional method with about half the amount used, such as 3 ml, and the coating quality was the same as in the conventional method. Further, since the coating amount is small, even when the substrate is large, it is possible to prevent the coating failure in which the coating film thickness is partially uneven like the conventional method which requires a large amount of coating material.

Further, in the present invention, the scattering of the coating material to the outside of the substrate is smaller than that of the conventional one, so that the scattered coating material caused by the conventionally generated coating material scattered to the outside of the substrate is reattached to the substrate. It can be said that the present invention is practically excellent in that it also reduces the contamination of the substrate.

[0033]

[Brief description of drawings]

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

FIG. 2 is a plan view showing an embodiment of the main part of the spin coating apparatus according to the present invention.

FIG. 3 is a bottom view showing an embodiment of the nozzle of the spin coating apparatus according to the present invention.

FIG. 4 is a plan view showing an example of dropping of the coating material according to the present invention.

5A to 5C are plan views showing an example of spin coating of the coating material according to the present invention in the order of rotation.

6A and 6B are plan views showing an example of spin coating of a coating material, which was carried out for comparison with the present invention.

FIG. 7 is a plan view showing an example of a dropping shape of a coating material by a conventional method.

[Explanation of symbols]

 1 Substrate 2 Nozzle 3 Nozzle Arm 4 Discharge Port 5 Spin Cup 6 Vacuum Chuck 7 Tube 8 Tank 9 Coating Material 10 Motor 11 Driving Device 12 Pressurizing Device A Centrifugal Force B Inertia Moment C Synthetic Force D Dropping Start Position E Dropping End Position

Claims (2)

[Claims] 1. In a spin coating method used as a means for coating a coating material with a uniform film thickness on a substrate such as a rectangular glass plate or a metal plate, it is dropped onto the central portion of the rectangular substrate before rotation. A spin coating method, characterized in that the coating material has a substantially rectangular shape that is rotated by about 90 ° in the substrate rotation direction with respect to the center of the substrate, and then the substrate is rotated to apply the coating material. 2. A substrate rotating means for placing and fixing and rotating a rectangular substrate, a coating material supplying means for supplying a coating material to a nozzle, a nozzle arm for moving the nozzle up and down and retracting and approaching from the rotating means, and a nozzle. Is provided with a substantially rectangular slit-shaped coating material discharge port, and the discharge port is moved by keeping the long side of the discharge port parallel to the long side of the substrate and parallel to the short side of the substrate. A spin coating apparatus comprising: a dropping unit configured to drop a coating material on a central portion of the substrate in a substantially rectangular shape rotated about 90 ° in a substrate rotation direction with respect to a center of the substrate.