JPH08141480A - Method and device for removing excess coating liquid at end of substrate surface - Google Patents

Abstract

PURPOSE: To easily, rapidly and surely remove excess coating liquid remaining at the end of coating the coating liquid, such as photosensitive resin, on the surface of a large-sized glass substrate of a color filter for LCDs, etc. CONSTITUTION: After a coating liquid film Ra is applied on the substrate S, an absorbent material sheet is advanced toward the end edges S2 of the substrate and in succession, groove parts of channel-shaped pressing members 21 are pressed to the parts of the absorbent sheet 20 pressed thereto from behind the sheet to hold the absorbent sheet 20 between the pressing members 21 and the end edges S2 of the substrate. As a result, the absorbent sheet 20 absorbs the coating liquid by being brought into force contact with the excess coating liquid, by which the coating liquid is removed and simultaneously the coating liquid infiltrating the end edges S2 of the substrate is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing an excessive coating liquid at the edge of a substrate surface after the coating liquid is applied to a single substrate such as a large glass substrate typified by a color filter for LCD, and the method thereof. Relates to a device used in.

[0002]

2. Description of the Related Art Heretofore, a spin coating method has been known as a method of coating a coating liquid on a single substrate such as a large glass substrate represented by a color filter for LCD. This method has a drawback that the coating efficiency is as low as about 10% and that the coating film becomes too thick at the corners of the substrate. There are knife coating method, roll coating method, and die coating method as a method for solving this drawback and for efficiently applying the coating liquid to the single-wafer substrate. In order to obtain a uniform film thickness using these methods, However, there is a problem that the smoothness of the substrate surface must be less than the coating accuracy. As a liquid coating method that can also solve this problem, the applicant has proposed a method in which a coating liquid bead is formed between the substrate surface and the coating head, and the substrate and the coating head are relatively moved to apply the coating liquid to the substrate surface. Previous international application PCT / JP 94
/ 00845 (International filing date: May 27, 1994).

[0003]

When the coating is carried out using the knife coating method, the roll coating method, the die coating method described above, or in the method described in the above-mentioned international application, the coating of the substrate is completed at the end of the coating. Excessive coating liquid remains on the edges, and due to this residual liquid, the uniform area of the coating film thickness is reduced, and partial poor drying occurs.
This is a factor that hinders the quality of the coating film.

Therefore, in the method disclosed in the above international application,
In order to remove the excess coating liquid, the excess coating liquid is removed by vacuum suction or an absorbent roll. However, the removal of the coating solution by vacuum suction takes time to be performed over the entire coating width, and it is necessary to treat the absorbed excess coating solution, which requires space for installing a pipe and a vacuum source. Further, the removal by the absorptive roll, especially when using an organic solvent-based coating liquid, there is a problem in terms of roll durability and washability, there is a problem that the material of the roll is limited, Has a problem that a large amount of cleaning solvent needs to be used since it must be cleaned after use, and a problem that it is mechanically complicated and requires a large installation space.

The present invention has been made to solve the above-mentioned problems, and its purpose is to be inexpensive because the principle for absorbing excess coating solution is simple, and to absorb absorption in a short time. An object of the present invention is to obtain a method and an apparatus for removing the excess coating liquid at the end of the substrate surface, which can be surely performed and does not require post-treatment or cleaning of the absorbing liquid.

[0006]

According to a first aspect of the present invention, excess coating liquid remaining near the edge of the substrate surface is removed at the end of coating of the coating liquid on the substrate surface. In this method, when the coating liquid is applied to the surface of the substrate, the absorbent material is pressed against the edge of the substrate where the excess coating liquid remains, over the entire coating width, and It is characterized in that the remaining coating material is brought into contact with the remaining substrate surface portion and the excess coating liquid is absorbed by the absorbing material.

According to a second aspect of the present invention, in the method of the first aspect, an absorbent sheet is used as the absorbent material, and the absorbent sheet is fed with respect to the substrate so that different portions thereof sequentially absorb the excess coating liquid. To do so.

According to a third aspect of the present invention, in the method of the first or second aspect, when the absorber is pressed against the edge of the substrate and the absorber is brought into contact with the substrate surface portion where the excess coating liquid remains, At least, the absorber is pressed from behind by the pressing member to the substrate surface portion where the excess coating liquid remains.

According to a fourth aspect of the present invention, there is provided an apparatus for removing excessive coating liquid on the edge of a substrate surface so as to be movable back and forth toward the edge of the substrate supported by the liquid coating apparatus for the substrate surface on the side where the excessive coating liquid remains. A reciprocating member, an absorber supported by the tip of the reciprocating member, and a driving means for advancing the reciprocating member so that the absorber is pressed against the edge of the substrate at the end of liquid application on the substrate surface. And supported by the tip of the reciprocating member,
When the reciprocating member advances, the absorbent material is provided with a pressing member that presses the absorbent material from at least the substrate surface portion where the excess coating liquid remains.

According to the fifth and sixth aspects of the present invention, in the excess coating liquid removing apparatus according to the fourth aspect, the pressing member is composed of a channel member and a rotatable member which are opened in the direction toward the edge of the substrate. To be done.

[0011]

In the method for removing excess coating liquid according to the first aspect of the present invention, when the coating of the liquid on the surface of the substrate is completed, the absorbent is first pressed against the edge of the substrate, and then the absorbent has the excess coating liquid near the edge. The excess coating liquid is brought into contact with the substrate surface portion and absorbed by the absorbing material.

In the method for removing excess coating liquid according to claim 2,
Every time the absorbent sheet is pressed against the substrate, the excess coating liquid is sequentially absorbed by the different portions.

In the method for removing excess coating liquid according to claim 3,
The absorber is pressed from the back by the pressing member and pressed against a predetermined position of the substrate to come into contact therewith.

In the apparatus for removing excess coating liquid according to claim 4,
At the end of the application of the liquid to the substrate surface, the reciprocating member is advanced toward the substrate edge by the driving means, the absorbent material is pressed against the substrate, and then the pressing member pushes the absorbent material from the front and back to excess the absorbent material. The surface of the substrate on which the coating liquid remains is brought into contact. As a result, the excess coating liquid is well absorbed by the absorbent material.

In the excess coating liquid removing device according to the fifth and sixth aspects, the pressing member composed of the channel member and the rotating member has a special structure, so that part of the absorbing material is
Make sure that the excess coating liquid contacts the surface of the substrate where it remains.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. Before that, an example of a method for applying a coating liquid to a substrate will be described with reference to FIGS. 1 to 4.

The single-wafer substrate S applied by the present invention is typically a large glass substrate for LCD color filters, and the liquid applied to the substrate forms a fine pattern on the glass substrate. It is a photosensitive resin. Although the glass substrate is inflexible, the substrate treated in the present invention is not limited to such a glass substrate, and may be plastic, metal, paper, or the like, and the substrate itself may be flexible. As the liquid to be applied, various liquids such as water-based and solvent-based liquids can be used, and pigments, dyes, fillers, sensitizers, resins, additives and the like can be mixed alone or in combination. In, S is a substrate. FIG. 1 shows a state at the time of disclosure of the liquid application on the substrate S. As shown in FIG. 1, the holder 8
The substrate S is adsorbed and held on the lower adsorbing surface thereof at an angle θ with respect to the horizontal. And the highest edge S1 of the substrate S
Immediately below the lower surface in the vicinity of the
The position of the holder 8 is determined so that the 3 is positioned with a certain clearance.

A coating liquid R such as a photosensitive resin is stored in a coating liquid tank 15 and is sent into the coating head H by a liquid feeding means such as a pump 16 and is sent upward from the slit 13. The coating liquid bead B is formed. The coating liquid bead B is formed on the lower surface (main surface) of the substrate S and the coating head H.
The liquid bead B is formed as a liquid pool of the coating liquid R in the clearance between the liquid bead B and the lower surface of the substrate S. The minimum clearance between the lower surface of the substrate and the coating head H is the coating liquid R
The coating liquid R is set so that the coating liquid bead B is formed without spilling from the clearance due to physical properties such as viscosity and surface tension. A meniscus L1 facing the lower side of the substrate S when the coating liquid bead B is formed as shown in FIG.
A meniscus L2 facing the high side of the substrate is formed,
Due to the inclination angle θ, the height dimensions h1 and h2 of the meniscuses L1 and L2 are h1> h2.

Next, in order to apply the coating to the main surface which is the lower surface of the substrate S from the coating start state shown in FIG.

While maintaining the clearance constant,
When the holder 8 is moved diagonally upward to the right from the position of FIG. 2 along a guide rail (not shown), the holder of FIG.
As shown in FIG.
To the right diagonally upward. In parallel with this, when the coating liquid R is continuously sent to the coating head H by the coating liquid pump 16 and the beads B are continuously formed, the coating liquid R sequentially adheres to the lower main surface of the substrate S to form the coating layer Ra. It is formed. During this coating step, the coating liquid R is supplied to the coating liquid bead B by the pump 16 so as to supplement only the sequentially coated amount so that the bead shape is kept constant. Then, as shown in FIG. 4, when the coating head H reaches the final end of the coating range close to the lowest edge S2 of the substrate S, the movement of the substrate S is stopped and then remains in the clearance. After removing the coating solution bead B, the coating head H is moved to the substrate S if necessary.
Remove it to a place where it does not interfere with the operation.

After that, the substrate S is set horizontally, upward or downward, and in the drying unit, the coating film Ra is formed by using a drying means such as a hot plate, hot air, or a far infrared heater.
Is dried to form a uniform coating film.

The method of coating a liquid on a substrate performed as described above is basically the same as the applicant's international application PCT / JP 91.
/ 00845.

When the film Ra of the coating liquid is formed on the surface of the substrate S as described above, the excess coating liquid Rb remains near the lower edge S2 of the substrate S as shown in FIG. Such accumulation of the excess coating liquid Rb also occurs when the coating liquid film Ra is formed by a method other than the direction shown in FIGS. 1 to 4. The present invention is intended to remove such a residual excess coating liquid.

FIG. 5 shows an embodiment of an apparatus for removing the residual excess coating liquid. In FIG. 1, reference numeral 1 is a coating liquid coating device having the same operation principle as shown in FIGS.
The excessive inclination θ shown in (3) is zero or close to zero. The holder 8 is pivotally supported by the shaft 2 so that the inclination angle θ can be adjusted and the holder 8 can be turned upside down. The substrate S is held on the lower surface of the holder 8, and the coating liquid film Ra is already formed on the lower surface of the substrate S.

A coating head H is provided below the holder 8. The coating head H sends the coating liquid upward by the same principle as in the case shown in FIG.
It has the same slit as 3 (Fig. 1). In the case of FIG. 1, the substrate S is configured to move with respect to the coating head H, but in the example of FIG. 5, the substrate S supported by the holder 8 does not move, and the coating head H is shown by a solid line. And, it is adapted to reciprocate in a direction indicated by a virtual line arrow. The coating head H is fixed on a traveling table 3 having a built-in up-down drive mechanism, and the traveling table 3 is screwed onto a feed screw 5 supported on a base 4 to rotate the feed screw 5 so as to be shown in the drawing. It is sent to the left and right. The feed screw 5 is rotationally driven by the servo motor M. The base 4 can be configured to be tiltable according to the tilt angle of the holder 8.

In order to form the coating liquid film Ra, the coating head H is moved from the right side to the left side in FIG. As a result, as mentioned above,
In the figure, the excess coating liquid remains near the left edge of the lower surface of the substrate S. The excess coating solution is indicated by Rb in FIG.

According to one embodiment of the method of the present invention, the overcoat Rb is removed by the steps shown in FIGS.
As shown in FIG. 6, the absorber 20 is provided so as to face the edge S2 of the substrate S having the excess coating liquid Rb. The absorbent material 20 can be composed of a fibrous material sheet capable of absorbing the coating liquid R, for example, a non-woven fabric or other porous sheet. An example of the absorbent material is Bencot wiper (trade name of Asahi Kasei Corporation). The absorber 20 is supported by a member (not shown) so as to stretch in the vertical direction. A pressing member 21 is provided behind the absorbent material 20. The pressing member 21 is composed of a channel material opened toward the edge S2.

In order to remove the excess coating liquid Rb in the vicinity of the edge S2 of the substrate, the absorbent 20 is moved toward the edge S2 as shown in FIG.
Next, as shown in FIG. 8, the pressing member 21 is pressed from behind the absorbent material 20 pressed against the edge S2 to move the edge S.
The absorber 20 is added to the upper and lower surface portions of the substrate 2 and the adjacent portions of the substrate 2. As a result, a part of the absorbent material 20 is sandwiched between the edge S2 and the pressing member 21. In order to cause such a state, the width of the inner groove of the pressing member 21, which is the channel material, is of course the value obtained by adding the thickness of the substrate S to twice the thickness of the absorber 20. It is better to set the value to or slightly smaller than.

As shown in FIG. 8, since the absorbent material 20 surrounds the edge S2, the excess coating liquid Rb is absorbed by the absorbent material 20 on the lower surface side of the substrate, and further tries to wrap around to the edge of the substrate. The coating liquid is also absorbed neatly. Therefore, as shown in FIG. 9, when the pressing member 21 is retracted to the left in the drawing and the absorber 20 is also retracted, the substrate edge S2
The excess coating liquid Rb in the vicinity of is completely disappeared, the portion becomes slightly thin, and the coating liquid film Ra having a uniform thickness is left in the other portions. The absorbed coating liquid is Rb in FIG.
Indicated by.

As mentioned above, in the method of the present invention,
Not only the absorbent material 20 is pressed against the edge of the substrate, but also a part of the absorbent material 20 is brought along with a part of the surface of the substrate on the side where the excess coating liquid is present, so that the excess coating liquid is absorbed quickly and reliably. Can be removed.

FIG. 5 shows an excessive coating liquid removing device for carrying out the steps shown in FIGS. 6 to 9. A stand 23 is fixedly installed adjacent to the base 4, and an air cylinder 24 as an example of a driving unit is installed on the stand 23. The air cylinder 24 has a piston rod 2 as a reciprocating member, and the piston rod 25 can freely reciprocate left and right in FIG. Piston rod 25
The pressing member 21 of the channel member is horizontally fixed to the tip (right end) of the.

As shown in FIG. 10, the piston rod 25
Is fixed in the middle of the pressing member 21, and the intermediate portions of the vertical arms 27, 27 are fixed to both ends of the pressing member 21 as shown in FIG. And the arms 27, 2
Shafts 28, 28 are provided on the inner side of the upper and lower ends of 7, and the rolls 20a of the absorbent sheet 20 are
20a is rotatably supported. The upper part of the two rolls 20a, 20a is the drive side, and its shaft is connected to a rotary drive source such as a stepping motor Mo. Between the rolls 20a, 20a,
The absorbent sheet 20 is provided so as to be adjacent to the groove side of the pressing member 21.
Are stretched in the vertical direction. Therefore, by rotating the upper roll 20a on the drive side, the absorbent sheet 2 is transferred from the other roll 20a to the drive side roll 20a.
0 can be gradually wound up. The lower roll 2
The shaft 0a is connected to a braking device 29 such as a powder brake.

The operation of the excessive coating liquid removing device as described above will be described. As shown in FIG. 5, after the coating liquid film Ra is formed on the lower surface of the substrate S by the coating head H, the air cylinder 24 is operated to move the piston rod 25 forward to the right in the figure. As a result, the piston rod 2
5 reaches the position of FIG. 5, the absorbent sheet 20 on the front side of the pressing member 21 at its tip is pressed as shown in FIG. 7, and then the pressing member 21 causes the state as shown in FIG. Therefore, as described above, the excess coating liquid Rb is reliably absorbed by the absorbent 20 and removed. The pressing member 21 keeps the absorbent 20 in contact with the substrate surface in the state of FIG. 8 to ensure the absorption of the excess coating liquid. While the coating liquid is being absorbed as described above, the coating head H is returned to the coating start position through the solid line position and the virtual line position for the next coating step. Then, after the removal of the excess coating liquid is completed, the air cylinder 24 is operated to retract the piston rod 25, the pressing member 21, and the absorbent 20 to the left in FIG. In addition, in parallel with that, the drive side roll 2
Rotate 0a a small amount to feed the absorber 20 in the vertical direction,
The new absorbing material portion 20 is made to face the substrate edge S2 to prepare for the next excess coating liquid absorbing step.

12 to 15 show another embodiment of the excess coating liquid removing device according to the present invention. This embodiment is different from the embodiment of FIG. 5 in that the pressing member is constituted by a rotating member 30 made of a plate material having a width over the entire coating width of the substrate S instead of the channel material. Rotating member 3
0 is pivotally supported by a shaft 31 and is reciprocally rotatable between the position shown in FIG. 12 and the position shown in FIG.
It is rotated by the drive device 32 shown in FIG. The drive device 32 and the rotating member 30 are supported by the tip of a reciprocating member such as the piston rod 25 shown in FIG. Also in this embodiment, the absorbent sheet 20 has the same structure as in FIG.
It is supported in the same way as shown in.

In this embodiment, the piston rod 25 is moved forward to move the absorbent sheet 20 to the substrate S as shown in FIG.
14 after being pressed against the edge S2 of the
When rotated in the arrow direction indicated by, the rotating member 30 moves the portion of the absorbent sheet 20 adjacent to the lower side of the substrate edge S2,
As shown in FIG. 4, it is pressed against the lower surface of the substrate adjacent to the edge S2. As a result, the excess coating liquid Rb is positively absorbed by the absorbent sheet 20 and disappears. Next, when the piston rod 25 is retracted, the state shown in FIG. 15 is obtained.
Also in this embodiment, the partial excess coating liquid of the absorbent sheet 20 can be reliably removed.

Although the liquid is applied to the lower surface of the substrate in the above-mentioned embodiments, the above-described principle of the present invention can be used when the liquid is applied to the upper surface of the substrate. Is. Further, the movement of the substrate and the coating head in the coating liquid film direction may be relative movement, and either one may move.

[0037]

According to the invention of claim 1, in addition to pressing the absorbent material against the edge of the side of the substrate on which the residual excess coating solution is present, a part of the absorbent material is applied to the substrate surface on which the residual excess coating solution is present. Since it is also brought into contact with, it is possible to reliably remove the excess coating liquid. Further, according to the present invention, there is an advantage that the excess coating liquid can be removed in a short time by a simple means as compared with the conventional roll cleaning and vacuum suction. Further, since the edge portion of the base end edge can be cleanly treated by the absorbent material, it is possible to prevent the substrate from being contaminated by the residual coating liquid.

According to the second aspect of the present invention, the absorbent material is formed into a sheet and is used while being fed with respect to the substrate. Therefore, a new portion of the absorbent material is always used for absorbing the coating liquid for each substrate, and therefore the absorbent material is used. Is often performed, and the labor of washing the absorbent material with a solvent later is unnecessary.

According to the third aspect of the invention, the contact of the absorbent with the surface of the substrate having the residual excess coating liquid is performed by pressing the pressing member from the rear side of the absorbent, so that the contact of the absorbent with the surface of the substrate is prevented. Definitely done.

According to the fourth aspect of the present invention, the absorber can be surely brought into contact with the substrate surface portion where the excess coating liquid remains by pressing from the back of the pressing member, and the excess coating liquid can be kept in a short time. Can be removed easily. Further, since the edge portion of the substrate edge can be cleanly treated by the absorbing material, it is possible to prevent the substrate from being contaminated by the residual coating liquid.

According to the sixth aspect of the invention, when the reciprocating member moves forward, the rotating member can be rotated to positively bring the absorber into contact with the substrate surface.

[Brief description of drawings]

FIG. 1 is a principle diagram showing an example of a liquid coating apparatus for a substrate.

FIG. 2 is a diagram showing a state at the start of liquid application.

FIG. 3 is a diagram showing a state in the middle of liquid application.

FIG. 4 is a diagram showing a state at the end of liquid application.

FIG. 5 is a front view showing an excessive coating liquid removing device at the end portion of the substrate surface according to the present invention.

FIG. 6 is a diagram showing a state at the start of steps of an embodiment of the method for removing the excess coating liquid on the end portion of the substrate surface according to the present invention.

FIG. 7 is a diagram similarly showing the next step.

FIG. 8 is a diagram showing the next step in the same manner.

FIG. 9 is a diagram similarly showing a state at the time of completing the process.

FIG. 10 is a perspective view of a part of FIG.

11 is a partial cross-sectional side view seen from the left side of FIG.

FIG. 12 is a diagram showing a state at the time of starting a process in another embodiment of the present invention.

FIG. 13 is a diagram similarly showing the next step.

FIG. 14 is a diagram similarly showing the next step.

FIG. 15 is a diagram showing a state when the process is completed.

[Explanation of reference symbols] S substrate S2 substrate edge 8 substrate holder R coating liquid B bead Ra coating liquid film Rb excess coating liquid N coating head 20 absorber (sheet) 20a absorber roll 21 pressing member (channel member) 24 driving means (Air cylinder) 25 Reciprocating member (piston rod) 27 Arm 30 Pressing member (rotating member)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shunji Miyagawa 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd.

Claims (6)

[Claims] 1. A method of removing excess coating liquid on the edge of a substrate surface, which comprises removing excess coating liquid remaining near the edge of the substrate surface at the end of coating of the coating liquid on the substrate surface. At the end of coating, the absorbent material is pressed against the edge of the substrate where the excess coating liquid remains, and the absorbent material is brought into contact with the substrate surface portion where the excess coating liquid remains, A method comprising absorbing an excess coating liquid in an absorbent material. 2. A substrate surface according to claim 1, wherein an absorbent sheet is used as the absorbent material, and the absorbent sheet is fed with respect to the substrate so that different portions thereof sequentially absorb the excess coating liquid. Method for removing excess coating liquid on the edge. 3. A substrate surface portion on which at least excess coating liquid remains when the absorbent material is pressed against the edge of the substrate and brought into contact with the substrate surface portion on which excess coating liquid remains. 3. The method for removing excess coating liquid from the edge portion of the substrate surface according to claim 1, wherein the absorbent material is pressed from behind by a pressing member. 4. A reciprocating member provided to be movable back and forth toward an edge of a substrate supported by a substrate surface liquid coating device on a side where an excess coating liquid remains, and a tip end portion of the reciprocating member. A supported absorber, a drive means for advancing the reciprocating member so as to press the absorber against the substrate edge at the end of liquid application to the substrate surface, and supported by the tip of the reciprocating member, When the reciprocating member advances, the absorbent is provided with a pressing member that presses the absorbent material from at least the substrate surface portion where the excessive coating liquid remains, and the excessive coating liquid at the end portion of the substrate surface. Removal device. 5. The excess coating liquid removing device according to claim 4, wherein the pressing member is a channel material opened in a direction toward an edge of the substrate. 6. The excess coating liquid removing device according to claim 4, wherein the pressing member is a rotating member having a base end rotatably supported by a reciprocating member. .