JP2003260404A - Cleaning method of extrusion die head, coating apparatus comprising cleaning mechanism, and coating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make continuous coating by a die coater possible by cleaning a die head after discharging a solution. <P>SOLUTION: A porous structure body and a highly absorptive cloth made of ultrafine fibers are combined with each other to form a ventilative absorption block or roller. The center of the absorption body is penetrated and vacuum suction is carried out through the penetrated center so as to wipe a die head to which a coating material adheres after coating and clean it by suction and accordingly, the die head can be refreshed and continuous coating is made possible. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die head cleaning method for forming a liquid film by a die coater in device manufacturing, and a coating apparatus having the cleaning mechanism described above.

[0002]

2. Description of the Related Art When manufacturing a device such as a semiconductor or a flat panel display, a process for forming various liquid films such as an insulating film using a photosensitive material typified by a resist or polyimide is frequently used. Done. The liquid film described above has been applied by methods such as spin coating and printing, and spin coating has been introduced into various lines because a highly precise film can be obtained by a simple mechanism.

However, in spin coating, 95% or more of the dropped coating material is normally blown off by rotation to be a waste liquid. Further, at this time, it is necessary to surround the coating material so that the scattered coating material does not affect other devices, which makes the device bulky. Further, a droplet called a bead is generated at the edge portion of the substrate, the coating material is attached to the edge portion and the back surface of the substrate, and the substrate transport system and the surface of the hot plate are contaminated to generate particles. For this reason, it is often necessary to increase the number of processes and devices for treating the back end surface after the spin coating is finished. Also, the throughput is very slow.

As mentioned above, there are various problems.

On the other hand, in order to solve these problems, a coating apparatus using an extrusion type (die) has attracted attention and has already been put into practical use.

This coating apparatus has a slit, which is formed by at least two blades, in a die which is a liquid discharge section, and the coating material is extruded and coated onto a glass substrate or the like from this slit.

At this time, the die tip is brought close to the substrate, and the die tip and the substrate are precisely controlled with a gap of several tens of μm to several hundreds of μm, the coating material is pushed out from the above-mentioned slit, and the coating material of the coating material is inserted between the die tip and the substrate. The liquid film is formed on the substrate by forming the liquid layer and moving the die or the substrate in parallel. The liquid layer formed at this time needs to have a certain size to maintain the meniscus.

Therefore, compared with the spin coating, most of the coating material can be supplied to the substrate without scattering, so that there is little waste, and the coating film can be formed only by passing the substrate under the die. Therefore, the throughput is very good and the film is uniform. Can be obtained.

[0009]

However, in this coating method, the coating film is finished by stopping the liquid discharge and separating the die head from the substrate, so that the liquid layer between the die and the substrate must be destroyed. At this time, a large amount of coating material is required between the die and the substrate to maintain the liquid layer, and if the liquid layer is destroyed at the end of coating, this large amount of coating material cannot be brought all over the substrate and some head And may adversely affect the next coating such as streak unevenness and increase in film thickness at the start of coating. Further, there is a problem that the material remaining on the head may be dried and turned into particles, which may cause defects.

In order to solve these problems, the coating material at the tip of the head is scraped off by a metal roller or blade, or brush cleaning is performed after the application is completed or after the dummy discharge is performed. I can't solve it. Especially when the coating material is a high-viscosity and quick-drying material, the problem of not being able to scrape off with a blade or the like and affecting the next coating or causing particles is not easily solved, and stable continuous coating is possible. Often an obstacle.

Therefore, the present invention has been proposed in view of the conventional state of the art, and makes it possible to remove the coating material adhering to the tip of the die head and optionally refresh the tip of the die head, which affects the next coating. This is to create a head state that does not affect the temperature of the die head, further suppresses the occurrence of coating unevenness such as liquid pool streaks, enables uniform and high quality film formation, and prevents the generation of particles due to the drying of the coating material. The present invention intends to supply a cleaning method and a coating apparatus having the above-mentioned cleaning mechanism.

[0012]

In order to solve the above problems, a die head cleaning method according to the present invention and a liquid film coating apparatus having the aforementioned cleaning mechanism are provided with a breathable block or roller to which a chemical solution is attached. Press it against the die head that is holding. At this time, a block or roller having good liquid absorbability is used, and further, the central portion is hollowed out and vacuum suction is performed from that portion. Further, at this time, a cleaning liquid using a main solvent or the like of the coating material is applied to the die head or included in the block or the roller. Further, it is characterized in that a cleaning liquid is applied to the cleaning block itself and vacuum suction is performed from the center to perform self-cleaning.

According to the methods of claims 1 to 4, it has been clarified by the present inventors that the coating material adhered to the die head after coating or after dummy ejection can be removed by suction.

Further, it has been clarified by the study by the present inventors that the combined use of the methods of claims 5 to 7 makes it possible to remove the coating material which has dried and adhered with the passage of liquid ejection time by suction and can be washed. In addition, according to the study by the present inventors, it is possible to perform self-cleaning refreshment of the cleaning body every discharge or every several times by combining with claim 7, and to continuously use the cleaning block or the roller. It became clear.

When the method according to claims 8 and 9 is adopted, the above operation can be performed more efficiently.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0017]

Embodiment 1 FIG. 1 is a diagram schematically showing the features of the present invention.

In the figure, 1 and 2 are blades constituting a die, 3 and 4 are cleaning liquid discharge nozzles, 5 is a vacuum / waste liquid passage, 6 is a block having air permeability, and 7 is a highly absorbent cloth having a cushioning property. is there.

The cleaning mechanism according to the present invention removes the coating material adhering to the tip of the die head after coating and after the dummy ejection by pressing a suction block as shown in FIG. Further, this suction block is composed of a breathable porous structure, is hollowed through the central portion of the suction block, and is connected to a fixing shaft, and the shaft portion is connected to a vacuum suction mechanism.

As a result, the coating liquid sucked from the peripheral portion of the block is sucked to the central portion of the roll and removed from the suction block through the vacuum system from the block shaft portion, and at the same time, the coating material on the flock surface can be sucked. Further, in order to promote absorption, a super-absorbent cloth such as ultra-fine and high-density fine structure fibers may be wound around the block and used. This cloth also serves as a cushioning material when the head and block come into contact with each other.

When wiping and cleaning are further carried out, 3, in FIG.
As shown in FIG. 4, a cleaning liquid made of a main solvent of the coating material or the like is applied, and the coating material adhered to the tip of the die head is dissolved and removed by suction. During vacuum suction, a small amount of coating material is discharged from the die head to prevent the cleaning liquid from entering the slit and sucking out the coating material. In addition, the cleaning liquid is applied to the suction block during coating of the work, and the self-refreshing of the flocs is performed every coating or every fixed time.

When the coating material attached to the tip of the die head is sucked and removed by such a mechanism, the coating material attached to the die head is washed and refreshed to the state before coating. When the continuous coating operation was performed using this head, it was possible to perform coating without stripe unevenness.

[0023]

[Embodiment 2] FIG. 2 is a diagram schematically showing the features of the present invention.

In the figure, 1 and 2 are blades constituting a die, 3 and 4 are cleaning liquid discharge nozzles, 5 is a vacuum / waste liquid passage, 6 is a breathable block, and 7 is a highly absorbent cloth having cushioning properties. is there.

As a method of removing the coating material adhering to the die head by suction, a suction block shorter than the head as shown in FIG. 2 was used. When a short suction block is used, the tip of the head is wiped off like scanning so that it can be used for a long head. Further, a cleaning liquid discharge nozzle is provided outside the block, and the cleaning liquid can be applied to the coating material attached to the head and then wiped and sucked. Further, as shown in FIG. 2, the coating material on the tip side surface of the cutout head is sucked so as to match the tip shape of the head. When the coating material attached to the tip of the die head is sucked and removed by such a mechanism, the coating material attached to the die head is washed and refreshed to the state before coating even when the die head is long. When the continuous coating operation was performed using this head, it was possible to perform coating without stripe unevenness.

[0026]

[Embodiment 3] FIG. 3 is a diagram schematically showing the characteristics of the present invention.

In the figure, 1 and 2 are blades constituting a die, 3 and 4 are cleaning liquid discharge nozzles, 5 is a vacuum / waste liquid passage, 6 is a breathable roller, and 7 is a highly absorbent cloth having a cushioning property. is there.

A suction roller as shown in FIG. 3 was used as a method for removing the coating material adhering to the die head by suction. When a suction roller is used, the roller is pressed against the tip of the head and rotated to wipe it off, so that the coating material adhering to the side surface of the tip of the head can be easily sucked and removed because it is repeatedly wiped forward and backward. When the coating material attached to the tip of the die head is sucked and removed by such a mechanism, the coating material attached to the die head is washed and refreshed to the state before coating even when the die head is long. When the continuous coating operation was performed using this head, it was possible to perform coating without stripe unevenness.

[0029]

The cleaning method and the coating apparatus having the cleaning mechanism according to the present invention include: Cleaning and refreshing of the die head at the end of coating or at the end of dummy ejection can be performed up to a point where there is no effect on the next coating. 2. Even when the coating material is a highly viscous and highly dry material, it is possible to wash and remove the residue by suction. 3. The cleaning block or roller can be self-cleaning refreshed and continuously used, allowing continuous application of coating material. Such an effect can be obtained. Therefore, by using such a die head tip cleaning method and a coating film apparatus having the above-described cleaning mechanism, it is possible to perform advanced film formation in device manufacturing, and it is possible to mass-produce inexpensive and high-quality devices. Become.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing the features of the present invention.

FIG. 2 is a diagram schematically showing the characteristics of the present invention.

FIG. 3 is a diagram schematically showing the characteristics of the present invention.

[Explanation of symbols]

1, 2 blade 3,4 Cleaning liquid discharge nozzle 5 Vacuum and waste liquid 6 blocks (roller) 7 Super absorbent cloth

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F041 AA02 AA06 AB01 BA59 BA60                       CA02 CA28                 4F042 AA07 AA10 CC01 CC03 CC04                       CC07 CC08 CC11 CC14 CC15                       DA01

Claims (10)

[Claims] 1. An application method comprising an extrusion die having a slit formed by at least two blades, extruding a coating material from the slit, and at the same time moving the die or the substrate in parallel to form a liquid film on the substrate. The coating device is characterized in that the chemical liquid remaining in the vicinity of the liquid discharge portion of the die is removed by suction after the chemical liquid application or just before the chemical liquid application. 2. The mechanism for sucking and removing the chemical liquid has a block or a roller for absorbing the chemical liquid, and the residual chemical liquid in the vicinity of the liquid discharge portion of the die is removed by making contact with the tip and the side surface of the die head. The coating apparatus according to claim 1, wherein: 3. The chemical absorption block or roller is bored through the central portion thereof, and vacuum suction is performed from that portion to suck out the chemical contained in the block or roller, and at the same time, the chemical absorption block or roller is refreshed and the chemical is The coating device according to claim 2, wherein the suction removal is performed. 4. The coating apparatus according to claim 3, wherein the cleaning block or the roller is vacuum-sucked from the central portion, and the chemical solution is sucked and removed by a simple porous structure such as a sintered body of SUS. 5. The coating apparatus according to claim 1, wherein the chemical liquid is sucked and removed while applying a cleaning liquid containing a main solvent of the chemical liquid as a main component to the tip of the die head. 6. The coating apparatus according to claim 2, wherein a cleaning liquid is included in the chemical liquid absorption block or the roller, and the chemical liquid adhering to the die head is dissolved and sucked and removed. 7. A vacuum is suctioned from the center of the cleaning block or roller while applying a cleaning liquid to the cleaning block or roller itself, thereby self-cleaning the solid content and unnecessary substances remaining in the block and refreshing the block itself. The coating apparatus according to claim 5, which has a mechanism capable of performing the coating. 8. The chemical solution absorption block is grooved in a shape matching the die tip, and the block is scanned or moved in a state where the absorption block and the die tip are in close contact with each other,
The coating device according to claim 2, wherein the chemical liquid attached to the die head is removed by suction. 9. The chemical liquid absorption block or roller is used to discharge a small amount of the chemical liquid from the slit during the removal of the chemical liquid by using the cleaning liquid to prevent the cleaning liquid from entering the slit due to a capillary phenomenon or the like. The coating device according to claim 2, wherein the coating liquid is washed while suctioning and removing the chemical liquid and the cleaning liquid. 10. A coating method, characterized in that the cleaning according to any one of claims 1 to 9 is performed every coating and at regular intervals to continuously coat.