JP4835003B2 - Slit nozzle, bubble discharge method of slit nozzle, and coating apparatus - Google Patents

Description

  The present invention relates to a slit coater for applying a coating liquid onto a substrate, and in particular, a slit nozzle capable of smoothly and effectively discharging bubbles in the slit nozzle of the slit coater, and a bubble discharging method for the slit nozzle. The invention relates to a coating apparatus.

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 a color filter forming photoresist used in this 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 the manufacturing process of a liquid crystal display device, as a coating device such as a photoresist, the above 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 is often used. I came.
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.

  Instead of these coaters, the development and practical use of highly accurate slit coaters are progressing. The slit coater is a method of applying a coating solution to a glass substrate from a slit nozzle while horizontally moving a surface plate on which a glass substrate is placed or an application head, 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 a substrate (12) fixed on the surface plate (15) as indicated by an arrow. ) The coating solution is applied onto the substrate (12) while moving from the right to the left, and reaches the second standby position (D).

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. Along with this, the time required for discharging the bubbles tends to be excessive.

FIG. 5 is a cross-sectional side view on the YZ plane in the example of the slit nozzle (13) shown in FIG. FIG. 6 is a side sectional view on the XZ plane in the example of the slit nozzle (13) shown in FIG. As shown in FIGS. 5 and 6, a reservoir (manifold) (31) is provided in the slit nozzle (13), and a slit (32) is provided therebelow.
An injection port (42) is provided in the X direction at the center of the slit nozzle (13) in the longitudinal direction, and a coating liquid supply pipe (22) is connected thereto. Further, a vent (43) is provided in the center Z direction, and a bubble discharge pipe (24) is connected thereto.

As described above, every time the application of the coating liquid onto the substrate (12) is completed, the bubbles in the slit nozzle (13) are discharged with the safety in mind. For example, when the slit nozzle is adapted to a glass substrate having a size of about 1.5 m × 1.8 m, the distance from the center to the end is about 75 cm.
Thus, when the distance in the longitudinal direction of the slit nozzle (13) is increased, the bubbles may remain in the pool portion (manifold portion) (31) even if the bubbles are discharged for safety. .

When the supply of the coating liquid from the inlet (42) of the slit nozzle (13) is resumed, the remaining bubbles without being discharged are collected (manifold portion) as shown by symbol (E) in FIG. ) Move and stay at the end in (31).
In the slit nozzle (13), it is required that the coating liquid is uniformly pressurized and the coating liquid flows uniformly, but if bubbles remain in the reservoir (manifold section) (31). This causes a problem that the flow of the coating liquid becomes non-uniform and adversely affects the thickness of the coating film.

In addition, the bubbles may enter the accumulation portion (31) from the discharge port (41), and the bubbles that have entered from the discharge port (41) tend to accumulate at the end in the accumulation portion (31).
Furthermore, if the coating liquid is coated on the substrate through the slit (32) with air bubbles mixed in, a pinhole or the like is generated on the pixel of the color filter after the exposure and development processing, and the color filter is a pin. It becomes a defect called a hole.
Japanese Patent Laid-Open No. 9-253556 JP-A-8-274014 JP 2002-66487 A JP 2002-45760 A

  The present invention has been made to solve the above-described problem, and when applying a coating liquid onto a large substrate using a slit coater, it is effective to smoothly and efficiently discharge bubbles accumulated in the slit nozzle. In other words, it is an object of the present invention to provide a slit nozzle that can sufficiently discharge bubbles in a short time with a small amount of coating solution. It is another object of the present invention to provide a method of discharging bubbles in a slit nozzle that can sufficiently discharge bubbles in a short time with a small amount of coating liquid when discharging bubbles in the slit nozzle. Another object is to provide a coating apparatus using the slit nozzle.

  The present invention is characterized in that, in a slit nozzle of a slit coater for applying a coating liquid on a substrate, vent holes for discharging bubbles in the slit nozzle are provided at both ends in the longitudinal direction of the slit nozzle. It is a slit nozzle.

  Further, the present invention provides the slit nozzle according to the above invention, wherein the upper portion in the reservoir portion of the slit nozzle is inclined so as to gradually increase from the center portion of the slit nozzle toward both end portions. Nozzle.

  Further, the present invention provides the slit nozzle according to the above invention, wherein the discharge of the coating liquid containing bubbles from the air vents provided at both ends is performed independently at both ends. It is.

  Further, the present invention is to discharge bubbles from the vent holes provided at both ends in the longitudinal direction of the slit nozzle when discharging bubbles in the slit nozzle of the slit coater that applies the coating liquid onto the substrate. This is a feature of the bubble discharge method of the slit nozzle.

  Further, the present invention is the method for discharging bubbles of the slit nozzle according to the above invention, wherein the upper part in the reservoir part of the slit nozzle is inclined so as to gradually increase from the central part of the slit nozzle toward both ends. This is a feature of the bubble discharge method of the slit nozzle.

  Further, the present invention is characterized in that, in the method of discharging bubbles of the slit nozzle according to the above invention, the discharge of the coating liquid containing bubbles from the vents provided at both ends is performed independently at both ends. This is a method for discharging bubbles from a slit nozzle.

  Moreover, this invention is a coating device using the slit nozzle of any one of Claims 1-3.

In the present invention, since the air vents for discharging the air bubbles in the slit nozzle are provided at both ends in the longitudinal direction of the slit nozzle, the air bubbles mixed in the slit nozzle and discharging the accumulated air bubbles smoothly and effectively, that is, The slit nozzle can sufficiently discharge bubbles in a short time with a small amount of coating solution.
Further, according to the present invention, the upper portion in the slit nozzle reservoir portion is inclined so as to gradually increase from the center portion of the slit nozzle toward both end portions, so that the bubbles can be discharged sufficiently more effectively. It becomes a slit nozzle that can. Further, according to the present invention, since the discharge of the coating liquid containing bubbles from the vents provided at both ends is performed independently at both ends, the bubbles can be sufficiently discharged more effectively. It becomes a slit nozzle that can be used.

In addition, since the present invention discharges bubbles from the vents provided at both ends in the longitudinal direction of the slit nozzle, the bubbles in the slit nozzle can be sufficiently discharged in a short time with a small amount of coating liquid. It becomes the discharge method. Moreover, since the upper part in the reservoir part of a slit nozzle inclines so that it may become gradually high toward the both ends from the center part of a slit nozzle, it becomes a more effective bubble discharge method of a slit nozzle. Moreover, since the discharge of the coating liquid containing bubbles from the vents provided at both ends is performed independently at both ends, a more effective slit nozzle bubble discharge method is provided.

  In addition, since the present invention is a coating apparatus using the slit nozzle, the coating apparatus can sufficiently, more effectively, or more effectively discharge bubbles in a short time with a small amount of coating liquid. It becomes.

  Hereinafter, embodiments of the present invention will be described in detail.

FIG. 7 is a side sectional view on the YZ plane showing an outline of an example of the slit nozzle (33) according to the present invention. FIG. 8A is a side sectional view taken along the XZ plane in the example of the slit nozzle 33 according to the present invention shown in FIG. 7, and FIG. 8B is a slit nozzle parallel to the XZ plane. It is a sectional side view in XF surface in the both ends of (33).
As shown in FIGS. 7 and 8 (a) and 8 (b), a reservoir (manifold) (31) is provided in the slit nozzle (33), and a slit (32) is provided therebelow.

An injection port (42) is provided in the X direction at the center in the longitudinal direction of the slit nozzle (33). Further, no vent hole is provided in the central Z direction.
In the Z direction at both ends in the longitudinal direction of the slit nozzle (33), a left vent (43A) and a right vent (43B) are provided on each of the left and right sides.

When discharging the bubbles in the reservoir (manifold portion) (31), the coating liquid is supplied from the inlet (42) in the center in the longitudinal direction of the slit nozzle (33), and the supplied coating liquid is From the left vent (43A) and the right vent (43B) at both ends, it becomes a mixture of bubbles and coating liquid, and then passes through the left bubble discharge pipe (24A) and the right bubble discharge pipe (24B) to the outside. Discharged.
Therefore, even if the distance in the longitudinal direction of the slit nozzle (33) increases and bubbles may remain in the reservoir (manifold) (31), the reference numeral (E) in FIG. As shown in Fig. 2, even if the gas stays at the end in the reservoir (manifold) (31), the bubbles are easily discharged from the left vent (43A) and the right vent (43B) at both ends. Is done.

FIG. 9 is an explanatory diagram showing an outline of an embodiment of a mechanism for supplying the coating liquid to the slit nozzle (33) and discharging the bubbles when the slit nozzle (33) according to the present invention is used. The YZ plane of FIG. 9 is a side view corresponding to the YZ plane of FIG.
As shown in FIG. 9, 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 consists of a left and right discharge system (20A, 20B) as a bubble discharge system, and a slit nozzle (33).

The left discharge system (20A) is composed of a left bubble discharge pipe (24A), a left on-off valve (25A), and a left waste liquid tank (26A), and the right discharge system (20B) is a right bubble discharge pipe (24B), right It consists of an open / close valve (25B) and a right waste liquid tank (26B).
The coating liquid tank (21) is filled with the coating liquid (27), and the left and right waste liquid tanks (26A, 26B) are discharged with the left and right waste liquids (a mixture of bubbles and the coating liquid) (28A, 28B).
) Has accumulated.

When applying the coating liquid, the left and right open / close valves (25A, 25B) of the bubble discharge system shown in FIG. 9 are closed, and the application liquid is injected into the inlet ( 42), and is applied to the substrate from the discharge port (41) through the reservoir (31) and the slit (32).
When discharging the bubbles, the left and right open / close valves (25A, 25B) are opened, and the bubbles mixed in the reservoir (31) are discharged together with the coating liquid from the left and right vents (43A, 43B).

The coating liquid is supplied from the inlet (42) at the center in the longitudinal direction of the slit nozzle (33), and is discharged together with bubbles from the left vent (43A) and the right vent (43B) at both ends in the longitudinal direction. Therefore, even if the bubbles are discharged in anticipation of safety in actual manufacturing, the supply amount of the coating liquid does not become excessive, and accordingly, the time required for discharging the bubbles does not become excessive.
That is, bubbles can be discharged smoothly and effectively with a small amount of coating solution in a short time.
This also prevents bubbles from remaining in the reservoir (manifold) (31), and in the slit nozzle (33), pressure is uniformly applied to the coating liquid, and the coating liquid flows uniformly. The film thickness is not adversely affected.

FIG. 10 is a cross-sectional side view on the YZ plane showing an outline of an example of the slit nozzle (53) according to claim 2. FIG. 11A is a side sectional view of the example of the slit nozzle (53) shown in FIG. 10, taken along the XZ plane, and FIG. 11B is a slit nozzle (53) parallel to the XZ plane. It is a sectional side view in the XG plane in both ends.
As shown in FIGS. 10 and 11 (a) and 11 (b), a reservoir (manifold) (51) is provided in the slit nozzle (53), and a slit (32) is provided therebelow.

An injection port (42) is provided in the X direction at the center in the longitudinal direction of the slit nozzle (53). Further, no vent hole is provided in the central Z direction.
In the Z direction at both ends in the longitudinal direction of the slit nozzle (53), a left vent (43A) and a right vent (43B) are provided on the left and right, respectively.

  As shown in FIGS. 10 and 11 (a) and 11 (b), the upper part in the reservoir part (51) is inclined so as to gradually increase from the center part of the slit nozzle (53) toward both ends. ing. By providing such an inclination, the bubbles mixed in the reservoir portion (51) can easily move to both end portions. A left vent (43A) and a right vent (43B) are provided at both upper ends of the reservoir (51), which is convenient for discharging bubbles.

In addition, the slit nozzle according to the present invention is characterized in that the discharge of the coating liquid containing bubbles from the air vents provided at both ends is performed independently at both ends. The amount of bubbles accumulated in the reservoir portion (manifold portion) is not always equal to the amount of bubbles on the left and right sides of the central portion of the slit nozzle (53).
When the difference between the amount of bubbles on the left side and the amount of bubbles on the right side is small, the effect is small, but when the difference is large, the amount of bubbles on the side with a large amount of bubbles is sufficiently discharged. In accordance with the discharge on the side, the coating liquid on the smaller side is also discharged.

  That is, in order to make the supply of the coating liquid from the inlet (42) when discharging the bubbles smaller and to sufficiently complete the discharge of the bubbles in a shorter time, the discharge of the coating liquid containing bubbles from the left end portion It is preferable that the coating liquid containing bubbles from the right end is discharged independently.

In order to discharge the coating liquid independently, for example, a method of providing a time difference between the opening and closing of the left opening and closing valve (25A) and the right opening and closing valve (25B) in FIG.
Alternatively, as shown by the dotted line in FIG. 9, each of the left discharge system (20A) and the right discharge system (20B) is provided with a left suction pump (30A) and a right suction pump (30B), It is also possible to perform an operation corresponding to the difference in the amount of bubbles on the right side.

  That is, according to the slit nozzle according to the second aspect, the bubbles can be sufficiently discharged in a short time with a small amount of coating liquid.

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 a sectional side view in the YZ plane in an example of the slit nozzle shown in FIG. It is a sectional side view in the XZ plane in an example of the slit nozzle shown in FIG. It is a sectional side view in the YZ plane which shows the outline of an example of the slit nozzle by this invention. (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 XF plane at both ends of the slit nozzle parallel to the XZ plane. 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 at the time of using the slit nozzle by this invention. It is a sectional side view in the YZ plane which shows the outline of an example of the slit nozzle concerning Claim 2. (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 XG plane at both ends of the slit nozzle parallel to the XZ plane.

Explanation of symbols

10 ... slit coater 11 ... stage 12 ... substrates 13, 33, 53 ... slit nozzle 14 ... frame 15 ... surface plate 20A with suction vacuum ... left discharge system 20B ...・ Right discharge system 21 ... Coating liquid tank 22 ... Coating liquid supply pipe 23 ... Supply pump 24 ... Bubble discharge pipe 24A ... Left bubble discharge pipe 24B ... Right bubble discharge pipe 25 ..Open / close valve 25A ... Left open / close valve 25B ... Right open / close valve 26 ... Waste liquid tank 26A ... Left waste liquid tank 26B ... Right waste liquid tank 27 ... Coating liquid 28 ... Waste liquid 28A ... Left waste liquid 28B ... Right waste liquid 30A ... Left suction pump 30B ... Right suction pump 31, 51 ... Reserved part (manifold part)
32 ... Slit 41 ... Discharge port 42 ... Injection port 43 ... Ventilation port 43A ... Left ventilation port 43B ... Right ventilation port A ... First standby position B ... Application Start position C ... Application end position D ... Second standby position
E: Position where the remaining bubbles move and stay

Claims (3)

In the slit coater slit nozzle that has a slit below the reservoir of the coating liquid, pressurizes the coating liquid of the reservoir uniformly and applies the coating liquid on the substrate,
A coating liquid injection port is provided at the central portion in the longitudinal direction of the reservoir,
Vents for discharging bubbles in the slit nozzle are provided at both ends in the longitudinal direction of the reservoir, and the upper portion in the reservoir of the slit nozzle extends from the center of the slit nozzle toward both ends. It is inclined to gradually increase,
The slit nozzle characterized by discharge | emission of the coating liquid containing the bubble from the vent provided in the said both ends independently at both ends . A slit is provided below the reservoir of the coating liquid, and when the bubbles in the slit nozzle of the slit coater that applies the coating liquid onto the substrate by uniformly pressurizing the coating liquid in the reservoir are discharged, the length of the reservoir The coating liquid was supplied from the injection port in the central part of the direction, and the upper part in the reservoir part was provided at both ends in the longitudinal direction of the reservoir part inclined so that the upper part gradually increased from the central part of the slit nozzle toward both ends. A method for discharging bubbles from a slit nozzle, wherein the bubbles are discharged independently from each other at both ends .   A coating apparatus using the slit nozzle according to claim 1.

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