JP4715144B2 - Slit nozzle application system - Google Patents

Description

  The present invention relates to a slit coater for applying a coating liquid onto a substrate, and in particular, when discharging bubbles in the slit nozzle of the slit coater, the amount of coating liquid used is reduced and the time required for discharging bubbles is reduced. The present invention relates to a slit nozzle application system for shortening.

In a liquid crystal display device or a plasma display panel, it is a useful means to use a color filter for purposes such as color display, reflectance reduction, contrast improvement, and spectral characteristic control.
In many cases, the color filter used in the display device is formed and used as a pixel. As a method for forming a pixel of a color filter for a display device, a photolithography method, a printing method, and the like can be cited as methods that have been put into practical use.

  For example, the pigment dispersion method is one method of this photolithography method, and the color filter forming photoresist used in the pigment dispersion method is spin-coated on a glass substrate using, for example, a spin coater. The coating film is subjected to UV exposure and development processing through a photomask to form pixels of a color filter for a display device.

Conventionally, in a manufacturing process of a liquid crystal display device, as a coating device such as a photoresist, a spin coater that rotates a glass substrate and spreads the coating solution after dropping the coating solution from a nozzle to the center of the glass substrate has been often used. It was.
This spin coater has the advantage of high film thickness accuracy, but if the glass substrate becomes large, it is difficult to implement it due to mechanical restrictions such as a motor, and more than 95% of the coating solution is wasted. There is a disadvantage that it is wasted.

For this reason, for example, in a glass substrate having a size of about 550 mm × 650 mm, a slit & spin coater (also called a coat & spin coater) has started to be used. This is a method of increasing the uniformity of the film thickness by applying the coating liquid to the glass substrate from the slit nozzle and then rotating the glass substrate.
In this method, although the utilization rate of the coating solution is greatly improved to 30 to 40%, the mechanical constraints such as the motor are the same, so it is difficult to further increase the size of the apparatus.

  In place of these coaters, slit coaters have been developed and put into practical use. The slit coater is a method in which a coating liquid is applied to a glass substrate from a slit nozzle while a platen on which a glass substrate is placed or a coating head is moved horizontally, and is 1 m × 1.3 m or 1.5 m × 1. A glass substrate having a size of about 8 m can be accommodated.

FIG. 1 is a plan view schematically showing an outline of an example of a slit coater. FIG. 2 is a side view of the slit coater shown in FIG.
As shown in FIGS. 1 and 2, the slit coater (10) schematically shown includes a stage (11) comprising a frame (14) and a surface plate (15) with a suction vacuum, and a slit nozzle (13). Has been.
The slit nozzle (13) is provided at the first standby position (A) on the right side of the stage (11) and above the frame (14). When applying the coating liquid onto the substrate, the slit nozzle (13) 13) moves to the left and applies the coating solution onto the substrate placed and fixed on the surface plate.

The operation of the slit coater (10) is as follows. First, the substrate (12) transported from the previous process by the first robot (not shown) is indicated by a white thick arrow (16), and a surface plate with suction vacuum is provided. (15) Place on top. The substrate (12) is fixed on the surface plate (15) by suction vacuum. Next, the slit nozzle (13) at the first standby position (A) on the right side of the stage (11) and above the frame (14) is an arrow. As shown in FIG. 2, the coating liquid is applied onto the substrate (12) while moving from the right to the left on the substrate (12) fixed on the surface plate (15), and the second standby position (D). To.

When the application of the coating liquid is completed, the second robot (not shown) carries the substrate (12) to the next process as indicated by the white arrow (17).
The bubbles mixed in the slit nozzle (13) are discharged at the second standby position (D) or the first standby position (A). For example, when it is performed at the second standby position (D), the slit nozzle (13) returns to the first standby position (A) when the discharge of the bubbles is completed.

FIG. 3 is an explanatory view schematically showing an example of a mechanism for supplying the coating liquid to the slit nozzle (13) and discharging the bubbles in the slit coater (10). FIG. 3 is a side view of the slit coater (10) shown in FIG. 1 from the right side in FIG.
As shown in FIG. 3, the mechanism for supplying the coating liquid and discharging the bubbles includes a coating liquid tank (21), a coating liquid supply pipe (22), a supply pump (23) as a coating liquid supply system, It comprises a bubble discharge pipe (24) as a bubble discharge system, an open / close valve (25), a waste liquid tank (26), and a slit nozzle (13).
The coating liquid tank (21) is filled with the coating liquid (27), and the waste liquid tank (26) stores waste liquid (a mixture of bubbles and coating liquid) (28) discharged together with the discharge of bubbles.

FIG. 4 is an explanatory diagram showing an example of the operation of applying the coating liquid onto the substrate (12) using the mechanism for supplying the coating liquid and discharging the bubbles shown in FIG. 4 is a side view of the slit coater shown in FIG. 1 as viewed from below in FIG. 1, similarly to FIG.
The slit nozzle (13) in the first standby position (A) is filled with the coating liquid, and the slit nozzle (13) is already in the state of discharging the bubbles. At this time, the on-off valve (25) is closed and the supply pump (23) is not operating.

When the slit nozzle (13) moves to the left in FIG. 4 and reaches the application start position (B), the supply pump (23) is actuated and passes through the application liquid supply pipe (22) to insert the slit nozzle (13). Supply of the coating liquid is started from the inlet (42), and coating on the substrate (12) is started from the discharge port (41).
The slit nozzle (13) applies the coating liquid onto the substrate (12) while moving to the left in FIG. Between the application start position (B) and the application end position (C), the on-off valve (25) is closed and the supply pump (23) is applied while being operated.

When the slit nozzle (13) reaches the application end position (C), the operation of the supply pump (23) is stopped, and the application of the application liquid onto the substrate (12) is completed. The slit nozzle (13) moves further to the left. However, while the slit nozzle (13) moves from the application end position (C) to the second standby position (D), the open / close valve (25) is closed and applied. The pressure pump (23) remains deactivated.
The slit nozzle (13) reaches the second standby position (D) and stops moving. At this second standby position (D) or first standby position (A), the bubbles that have entered the slit nozzle (13) and accumulated are discharged.

When discharging bubbles, the opening / closing valve (25) of the bubble discharge system is opened, and the pressure pump (23
) Is discharged, the bubbles in the slit nozzle (13) are discharged from the vent (43) to the waste liquid tank (26) through the bubble discharge pipe (24). When the bubbles are discharged, the bubbles are discharged as a waste liquid (28) mixed with the coating liquid.
The bubbles are discharged every time the application of the coating liquid onto the substrate (12) is completed as described above. While the bubbles are being discharged, the coating liquid is also discharged from the discharge port (41).

However, as described above, the coating liquid is applied on the substrate (12) by the above-described operation using the mechanism for supplying the coating liquid and discharging the bubbles shown in FIG. 3, and the slit nozzle (13). If the bubbles in the inside are discharged, the actual supply tends to cause the supply amount of the coating liquid to be excessive in order to discharge the bubbles in anticipation of safety. In addition, the time required for discharging the bubbles tends to be excessive.
JP-A-8-274014 JP 2002-66487 A

The present invention has been made in order to solve the above-described problems.When a coating liquid is applied onto a large substrate using a slit coater, the coating liquid is mixed into the slit nozzle and discharged from the accumulated bubbles. Do not make the supply amount excessive, that is, reduce the amount of coating solution used, and do not make the time required for air bubble discharge excessive, that is, reduce the bubble discharge time, and further eliminate defects caused by air bubbles. An object of the present invention is to provide a slit nozzle coating system that can reduce the cost and apply a coating solution onto a large substrate at a low cost.
Thereby, the application of the coating liquid onto the large substrate is inexpensive regardless of the type of the coating liquid.

The present invention relates to a slit nozzle coating system for a slit coater that coats a coating solution on a substrate, wherein a reservoir is provided in the slit nozzle, and a slit is provided below the slit nozzle. Inclined so as to gradually increase from both ends toward the center, and a vent is provided in the center of the upper part in the reservoir. At the standby position, the supply of the coating liquid to the slit nozzle is performed by a supply pump, and the slit during discharge of the bubbles in the nozzle to have a row by the suction of the coating solution in the slit nozzle containing air bubbles by the suction pump to discharge the air bubbles, the supply amount of the coating solution is carried out by pressurizing the feed pump, the suction of the suction pump The ratio of the discharge amount of the coating liquid accompanying the suction of bubbles performed by the nozzle and the discharge amount of the coating liquid from the discharge port is the suction pump with respect to the supply amount of the supply pump By adjusting the suction, the ratio of the amount of the coating liquid discharged from the discharge port is applied system of the slit nozzle, characterized by a low.

According to the present invention, a reservoir is provided in the slit nozzle, and a slit is provided below the slit, and an upper portion of the reservoir is inclined so as to gradually increase from both ends of the slit nozzle toward the center. A vent is provided in the center of the upper part of the nozzle, and at the standby position, the supply of the coating liquid to the slit nozzle is performed by a supply pump, and the discharge of the bubbles in the slit nozzle is performed by the suction pump including the bubbles by the suction pump. gastric row by suction, when discharging the bubbles, the supply amount of the coating solution is carried out by pressurizing the feed pump, and a discharge amount of the coating liquid due to the suction of the air bubbles to be performed by the suction of the suction pump, from the discharge port discharge rate of the ratio of the coating solution, by adjusting the suction of the suction pump to the feed amount of the feed pump, the ratio of the amount of the coating liquid discharged from the discharge port is in low Because it is a lit nozzle coating system, when applying a coating liquid on a large substrate using a slit coater, it does not excessively supply the coating liquid when it is mixed into the slit nozzle and the accumulated bubbles are discharged. That is, the amount of coating liquid used is reduced, and the time required for discharging bubbles is not excessive, that is, the time for discharging bubbles is shortened, and further, defects caused by bubbles are reduced, and the type of coating liquid Regardless of the case, it becomes a slit nozzle coating system capable of inexpensively coating a coating solution on a large substrate.

Embodiments of the present invention are described in detail below.
FIG. 5 is an explanatory view showing an outline of an embodiment of a mechanism for supplying the coating liquid to the slit nozzle (13) and discharging the bubbles in the slit nozzle coating system according to the present invention. FIG. 5 is a side view of the slit coater (10) shown in FIG. 1 from the right side in FIG.

As shown in FIG. 5, the mechanism for supplying the coating liquid and discharging the bubbles includes a coating liquid tank (21), a coating liquid supply pipe (22), a supply pump (23) as a coating liquid supply system, It comprises a bubble discharge pipe (24) as a bubble discharge system, a suction pump (30), an open / close valve (25), a waste liquid tank (26), and a slit nozzle (13).
The coating liquid tank (21) is filled with the coating liquid (27), and the waste liquid tank (26) stores waste liquid (a mixture of bubbles and coating liquid) (28) discharged together with the discharge of bubbles.

FIG. 6 is a side sectional view on the YZ plane in the example of the slit nozzle (13) shown in FIG. Moreover, Fig.7 (a) is a sectional side view in XZ surface in an example of the slit nozzle (13) shown in FIG. 5, FIG.7 (b) is a slit nozzle (13) parallel to XZ surface. It is a sectional side view in the XP plane in both ends.
As shown in FIG. 6 and FIGS. 7A and 7B, a reservoir (31) is provided in the slit nozzle (13), and a slit (32) is provided therebelow.

When applying the coating liquid, the open / close valve (25) of the bubble discharge system shown in FIG. 5 is closed and the suction pump (30) is not operated, and the pressure pump (23) is operated. The coating liquid is supplied from the injection port (42), and is applied to the substrate from the discharge port (41) through the pool portion (31) and the slit (32).
When discharging air bubbles, open the open / close valve (25) and operate the suction pump (30), and suck the air bubbles mixed in the reservoir (31) together with the coating liquid from the vent (43). Then discharge. At this time, the coating liquid is also discharged from the discharge port (41).

  In the example shown in FIG. 6, the upper part in the reservoir part (31) is inclined so as to gradually increase from both ends of the slit nozzle (13) toward the center. By providing such an inclination, the air bubbles mixed in the reservoir (31) can be easily moved to the upper center. A vent hole (43) is provided in the center of the upper part in the reservoir (31), which is convenient for discharging bubbles. Further, a slit nozzle (13) having a structure for discharging the mixed bubbles from both ends without providing an inclination in the upper part of the reservoir (31) is also conceivable.

An example of the operation of applying the coating liquid onto the substrate (12) using one embodiment of the mechanism for supplying the coating liquid and discharging the bubbles shown in FIG. 5 will be described with reference to FIG.
First, the slit nozzle (13) in the first standby position (A) is filled with the coating liquid, and the discharge of bubbles from the slit nozzle (13) is finished. At this time, the open / close valve (25) is closed, the suction pump (30) is not operated, and the supply pump (23) is not operated.

Next, the slit nozzle (13) is moved to the left in FIG. 4 until reaching the application start position (B). At this position, the supply pump (23) is operated to start supplying the coating liquid from the inlet (42) of the slit nozzle (13) through the coating liquid supply pipe (22), and from the discharge port (41) to the substrate (12 ) Start application on top.
The slit nozzle (13) applies the coating liquid onto the substrate (12) while moving to the left in FIG. Between the application start position (B) and the application end position (C), the open / close valve (25) is closed, the suction pump (30) is not operated, and the supply pump (23) is kept operating for application. Do.

Next, when the slit nozzle (13) reaches the application end position (C), the operation of the pressure pump (23) is stopped, and the application of the application liquid onto the substrate (12) is completed.
Next, the slit nozzle (13) is further moved to the left. While the slit nozzle (13) moves from the application end position (C) to the second standby position (D), the open / close valve (25) Close, do not operate the suction pump (30) and leave the supply pump (23) deactivated.
The movement of the slit nozzle (13) is stopped at the second standby position (D). At the second standby position (D) or the first standby position (A), the air bubbles mixed in the slit nozzle (13) are discharged.

To discharge bubbles, the open / close valve (25) of the bubble discharge system is opened, the suction pump (30) is operated, and the supply pump (23) is operated. Thereby, the bubbles in the slit nozzle (13) are quickly sucked together with the coating liquid from the reservoir (31), and the coating liquid containing bubbles is discharged to the waste liquid tank (26) through the bubble discharge pipe (24).
That is, the discharge of bubbles is completed in a short time with a small supply amount of the coating liquid.

  Further, when the bubbles are discharged, the amount of coating liquid supplied by pressurization of the supply pump (23) and the amount of discharge of the coating liquid accompanying the suction of bubbles performed by the suction of the suction pump (30), and the discharge port The ratio of the discharge amount of the coating liquid from (41) can be made appropriate by adjusting the suction of the suction pump (30) with respect to the supply amount of the supply pump (23). Therefore, the ratio of the amount of the coating liquid discharged from the discharge port (41) should be low while the bubbles in the reservoir (31) are being discharged at the second standby position (D). I can do it.

  That is, using the mechanism for supplying the coating liquid and discharging the bubbles shown in FIG. 3, the coating liquid is applied onto the substrate (12) by the operation as described above, and the bubbles in the slit nozzle (13) are removed. In contrast to the technique of discharging, the supply amount of the coating liquid does not become excessive, and the time required for discharging bubbles does not become excessive. Furthermore, since the bubbles are discharged by suction, they do not remain in the reservoir (31), and defects due to the bubbles are reduced.

By adopting the slit nozzle coating system according to the present invention, the amount of coating liquid used is reduced by about 20% and the time for discharging bubbles is about 30% even in the actual production, even if the bubbles are discharged safely. The result is reduced.
Further, the occurrence of defects due to bubbles in the slit nozzle (13) is approximately 0%.

It is a top view which shows the outline of an example of a slit coater typically. It is a side view of the slit coater shown in FIG. It is a side view which shows the outline of an example of the mechanism which performs supply of the coating liquid to a slit nozzle, and discharge | emission of a bubble of a slit coater. It is a side view which shows an example of the operation | movement which apply | coats a coating liquid on a board | substrate using the mechanism which supplies the coating liquid shown in FIG. 3, and discharge | releases a bubble. It is explanatory drawing which shows the outline of one Example of the mechanism which supplies the coating liquid to a slit nozzle, and discharge | releases a bubble in the coating system of the slit nozzle by this invention. FIG. 6 is a side sectional view on the YZ plane in the example of the slit nozzle shown in FIG. 5. (A) is a sectional side view in XZ plane in an example of the slit nozzle shown in FIG. (B) is a sectional side view on the XP plane at both ends of the slit nozzle parallel to the XZ plane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Slit coater 11 ... Stage 12 ... Substrate 13 ... Slit nozzle 14 ... Frame 15 ... Surface plate 21 with suction vacuum ... Coating liquid tank 22 ... Coating liquid supply Pipe 23 ... Supply pump 24 ... Bubble discharge pipe 25 ... Open / close valve 26 ... Waste liquid tank 27 ... Coating liquid 28 ... Waste liquid 30 ... Suction pump 31 in the present invention Reservoir 32 ... Slit 41 ... Discharge port 42 ... Injection port 43 ... Air vent A ... First standby position B ... Application start position C ... Application end position D ...・ Second standby position

Claims (1)

In a slit coater coating system of a slit coater that coats a coating solution on a substrate, a reservoir is provided in the slit nozzle, and a slit is provided below the slit, and the upper part in the reservoir is centered from both ends of the slit nozzle. The vent is provided in the center of the upper part of the reservoir, and the supply liquid is supplied to the slit nozzle by a supply pump at the standby position. bubbles of exhaust have rows by suction of the coating solution in the slit nozzle containing air bubbles by the suction pump, when discharging the bubbles, the supply amount of the coating solution is carried out by pressurizing the feed pump, which is performed by the suction of the suction pump The ratio of the discharge amount of the coating liquid accompanying the suction of the liquid and the discharge amount of the coating liquid from the discharge port adjusts the suction of the suction pump with respect to the supply amount of the supply pump. Of the slit nozzle coating system characterized in that it allows the ratio of the amount of the coating liquid discharged from the discharge port to the low to.

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