JP3541467B2 - Single wafer coating apparatus and method - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a single-wafer coating apparatus and a method therefor, and more particularly, to a single-wafer coating apparatus using a precision coating die coater and a method thereof. Then, in addition to forming a coating film on a substrate to create a color filter for a liquid crystal display, a liquid paint is thinly and uniformly applied to a surface of a material to be supplied supplied in a single-wafer method. It is suitable for the case.
[0002]
[Prior art]
Conventionally, a spinner, a bar coater, and a roll coater have been used in a coating process for producing a color filter for a liquid crystal display. Since it has been strongly required to improve the physical properties of the film, the use of a die coater has recently been studied.
[0003]
Die coaters have hitherto been widely used for thick-film coating and continuous application of high-viscosity paints, and gear pumps have been adopted as metering pumps for feeding the paints to the die coater (see, for example, Japanese Patent Application Laid-Open No. H05-205605). 285436).
By adopting such a configuration, it is considered that a liquid can be sent without a pulsating flow by a gear pump, and a substantially uniform coating film can be formed on the surface of a long material to be coated.
[0004]
[Problems to be solved by the invention]
However, if the above configuration is applied to single-wafer intermittent coating, the gears constituting the gear pump have gaps called top clearance and side clearance, and the sealing properties are often made of liquid (paint). Because it is not considered to be good, if it is applied as a paint discharge device for single-sheet intermittent coating where coating start and coating end are repeated at relatively short intervals, the liquid feed start operation and liquid feed end operation of the gear pump Not only may there be a time delay between the start and the end of the discharge of the paint actually sent, but also the quantitativeness of the feed may not be ensured. As a result, the uniformity of the coating film formed on the surface of the material to be coated is impaired. In view of such inconvenience and the fact that the amount of paint to be applied to the surface of one workpiece in sheet-fed coating may be considerably small, the present inventor has proposed a syringe pump as a metering pump. Considering the adoption of a piston type metering pump represented by
[0005]
In this case, the piston type metering pump itself has a good sealing property, and is also excellent in the linearity of the liquid feeding speed in one discharge stroke. Seems to be very useful.
However, since the piston type metering pump has to alternately repeat the suction filling operation and the discharging operation due to its structure, the time required for the single-wafer coating becomes longer. In order to reduce the time required for this single-wafer coating, the suction-filling operation speed must be increased.However, if the suction-filling operation speed is increased, line pressure loss or the like occurs in the paint suction side path. The resulting negative pressure causes bubbles, including a phenomenon known as cavitation. The presence of even a small amount of air bubbles in the paint path will impede the driving force of the liquid feed, significantly impairing the quantitativeness and prompt response of the paint supply, and consequently the uniformity of the coating film.
[0006]
Therefore, the productivity of the single-wafer coating is allowed to decrease, and the suction-filling operation speed is set to be small enough not to cause cavitation, generation of bubbles, and the like. In other words, there is a problem that the tact time, which is the time required for coating one sheet, is increased, and the productivity is reduced.
[0007]
[Object of the invention]
The present invention has been made in view of the above problems, and achieves high uniformity of paint supply by using a piston type metering pump as a metering pump, and significantly reduces the coating efficiency due to a suction filling operation. It is an object of the present invention to provide a sheet-fed coating apparatus and a method thereof that can be suppressed.
[0008]
[Means for Solving the Problems]
The sheet-fed coating apparatus according to claim 1, wherein the paint is sucked from a paint tank through a first liquid sending line and a switching valve by a piston type metering pump, and the switching valve and the second liquid sending line are drawn from the piston type metering pump. Supplying the sucked paint to the paint discharge slit of the paint discharge device through the substrate, and moving the predetermined position below the paint discharge device in a direction substantially orthogonal to the paint discharge direction while holding the workpiece to be coated by the stage. Thus, a sheet-fed coating apparatus for applying a coating material on the upper surface of the material to be coated, wherein at least two piston-type metering pumps and switching valves are provided, and 2 are provided in parallel with the liquid feed line, and the piston type metering pump and the piston type metering pump are provided so that the paint supply and the paint suction by these piston type metering pumps are performed at mutually different timings. And a control means for controlling the fine control valve independently.
[0009]
The sheet-fed coating apparatus according to claim 2 employs a substrate for a color filter as the material to be coated.
According to a third aspect of the present invention, in the single-wafer coating method, the paint is sucked from a paint tank through a first liquid sending line and a switching valve by a piston type metering pump, and the switching valve and the second liquid sending line are sucked from the piston type metering pump. Supplying the sucked paint to the paint discharge slit of the paint discharge device through the substrate, and moving the predetermined position below the paint discharge device in a direction substantially orthogonal to the paint discharge direction while holding the workpiece to be coated by the stage. Is a sheet-fed coating method for applying a paint on the upper surface of the material to be coated, wherein at least two piston-type metering pumps and switching valves are provided, and one piston-type metering pump supplies the paint. This is a method in which the suction of paint is performed by independently controlling another piston type metering pump while the pump is being performed, or a standby state is provided for supplying paint.
[0010]
The sheet-fed coating method according to a fourth aspect is a method in which a substrate for a color filter is employed as the material to be coated.
[0011]
[Action]
In the single-wafer coating apparatus according to claim 1, the paint is sucked from a paint tank by a piston type metering pump through a first liquid sending line and a switching valve, and the switching valve and the second liquid sending are drawn from the piston type metering pump. The suctioned paint is supplied to a paint discharge slit of a paint discharge device through a pipe line, and a workpiece to be coated is held by a stage, and a predetermined position below the paint discharge device is moved in a direction substantially orthogonal to the paint discharge direction. When applying paint on the upper surface of the material to be coated, the timing of the paint suction operation and the paint supply operation by one piston type metering pump is controlled by the timing of the paint suction operation and the paint supply operation by the other piston type metering pump. Because it can be controlled independently of timing, paint supply operation by any piston type metering pump should not cause cavitation. It is possible to perform the paint sucking operation by any other piston-type metering pump while min is performed at a slow speed. Therefore, while the paint suction operation is being performed by any one of the piston type metering pumps, the coating operation on the material to be coated can be performed by the other piston type metering pumps. As a result, it is possible to prevent the disadvantage that the efficiency of single-wafer coating decreases. In other words, since the paint suction operation can be performed in parallel with the paint supply operation, there is no need to increase the paint suction speed. The time can be significantly reduced.
[0012]
According to the sheet-fed coating apparatus of the second aspect, since a substrate for a color filter is employed as the material to be coated, a high-quality color filter can be produced.
In the single-wafer coating method according to claim 3, the paint is sucked from the paint tank through the first liquid feed line and the switching valve by the piston type metering pump, and the switching valve and the second liquid feeding are sucked from the piston type metering pump. The suctioned paint is supplied to a paint discharge slit of a paint discharge device through a pipe line, and a workpiece to be coated is held by a stage, and a predetermined position below the paint discharge device is moved in a direction substantially orthogonal to the paint discharge direction. By doing so, at the time of applying the paint on the upper surface of the material to be coated, at least two piston-type metering pumps and switching valves are provided, and while one piston-type metering pump is supplying the paint, Independently controlling other piston type metering pumps to suck paint or wait for paint supply. Te can be performed paint suction operation, moreover, it is not necessary to increase the paint suction speed, can significantly reduce the time required without sheet coating impairing the uniformity of the coating film.

[0013]
According to the sheet-fed coating method of the fourth aspect, if a substrate for a color filter is applied as the material to be coated, a high-quality color filter can be produced.
[0014]
【Example】
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing embodiments.
FIG. 1 is a view schematically showing one embodiment of a sheet-fed coating apparatus according to the present invention.
This single-wafer coating apparatus includes a paint tank 1, a micro syringe pump 2 as an example of a piston type metering pump, a paint discharge device 3 having a slit 3a for discharging paint, and a stage reciprocated by a ball screw mechanism 4a. 4, a position sensor 5 for detecting the position of the workpiece 8 on the stage 4, an output signal from the position sensor 5 and / or a state signal from an AC servomotor 4 b for driving a ball screw mechanism 4 a, paint discharge A sequencer 6 for controlling the paint discharger 3 and the AC servomotor 4b by using the state signal of the apparatus 3 as an input, and an output signal (such as a signal for controlling a micro syringe pump) from the sequencer 6 and a state signal of the micro syringe pump 2 are input. And a computer 7 (corresponding to control means) for controlling the micro syringe pump 2. The paint tank 1 and the micro syringe pump 2 communicate with each other by a paint suction pipe 1a (corresponding to a first liquid feed pipe). It communicates with a discharge pipe 3b (corresponding to a second liquid feed pipe). The micro syringe pump 2 is selectively connected to a paint suction pipe 1a and a paint discharge pipe 3b by a switching valve 2a. The micro syringe pump 2 and the switching valve 2a are provided in a pair, and are connected in parallel between the paint suction pipe 1a and the paint discharge pipe 3b. The coating material discharge device 3 is moved up and down between a position close to the upper surface of the material 8 to be coated supported on the stage 4 and a position sufficiently distant from the coating material 8. A coating operation start command from the sequencer 6 is issued. And rises in response to the coating operation end command. The computer 7 also controls the switching valve 2a. Although not particularly shown in FIG. 1, it is preferable to provide an on-off valve, a filter, and the like at predetermined positions of the paint suction pipe 1a. Further, the branch portion of 1a, 3b may be provided with a liquid supply path switching valve controlled by the computer 7.
[0015]
Therefore, a predetermined amount of paint can be sucked from the paint tank 1 by switching one of the switching valves 2a to the paint supply pipe side and operating the corresponding micro syringe pump 2 to suck the paint. In the meantime, the other switching valve 2a is switched to the paint discharge side, and the corresponding micro syringe pump 2 is operated to discharge the paint, whereby the sucked paint can be supplied to the paint discharge device 3. Therefore, while the other micro syringe pump 2 is discharging the paint, the one micro syringe pump 2 can perform the suction and filling of the paint, and the time required for the suction and filling operation of the paint reduces the coating efficiency. Inconvenience can be eliminated.
[0016]
Further, by lowering the paint discharge device 3 at the timing of or before the paint discharge from the paint discharge device 3, the distance between the paint discharge device 3 and the workpiece 8 supported on the stage 4 is set to a predetermined distance. I do. After the paint is discharged from the paint discharge device 3 and the paint bead is formed over the entire width of the slit 3a, the ball screw mechanism 4a is operated to move the stage 4 to convey the workpiece 8 at a predetermined speed. A coating film 8 a having a predetermined thickness can be formed on the workpiece 8.
[0017]
When the material to be coated 8 on the stage 4 has moved to the coating end position, this state is detected by the position sensor 5, and the switching valve 2a is switched to the paint suction pipe side to perform the paint suction operation again. Then, the coating material discharging device 3 is raised, and after the workpiece 8 is transferred to the next step, the stage 4 is moved back to prepare for coating on the next workpiece 8.
Specific Example Polyamide acid, N-methyl-2-pyrrolidone and chlorobrominated phthalocyanine green (CI Pigment Green 36) are mixed and dispersed to obtain a green colored coating film forming paint. An alkali-free glass substrate OA-2 (manufactured by Nippon Electric Glass Co., Ltd.) was selected as the material 8 to be coated, and sheet-by-sheet coating was performed using a die coater shown in FIG. However, the paint for forming a colored coating film was charged into the paint tank 1 and the inside of the liquid feed path up to the paint discharge device 3 was filled with the paint in advance. In the following description, one micro syringe pump is indicated by 2-a, a switching valve is indicated by 2a-a, the other micro syringe pump is indicated by 2-b, and a switching valve is indicated by 2a-b.
[0018]
The switching valve 2a-a is switched to the paint suction pipe side, the micro syringe pump 2-a is driven to the suction side at a speed of 300 μl / sec to fill 3600 μl of paint, and the switching valve 2a-a is switched to the paint discharge pipe side. To prepare for coating.
In this state, the stage 4 is operated to convey the workpiece 8, the paint discharging device 3 is lowered to a predetermined position, and the micro syringe pump 2-a is turned on the discharge side substantially simultaneously with the lowering of the paint discharging device 3. To start the discharge of the paint, and after the paint bead over the entire width of the slit 3a is formed, the stage 4 is operated to convey the workpiece 8 to perform the coating. In this case, a stable coating film can be continuously formed by equilibrating the coating material consumed for forming the coating film and the coating material supplied from the slit 3a of the coating material discharging device 3. When the material to be coated 8 reaches the coating end position, the operation of discharging the paint of the micro syringe pump 2-a is stopped, and then the coating material discharge device 3 is raised to move away from the material 8 to be coated. Finished work.
[0019]
Further, in parallel with the above coating operation, the switching valves 2a-b were switched to the paint and the pipeline side, and the micro syringe pump 2-b was driven to the suction side at a speed of 300 µl / sec to fill 3600 µl of the paint. In this case, the filling was started simultaneously with the start of the operation of the stage 4. After the coating by the micro syringe pump 2-a is completed, the stage 4 transfers the workpiece 8 to the next step, and reversely moves to a predetermined position to receive the next workpiece 8. The paint filling operation of the micro syringe pump 2-b was completed before the stage 4 returned to the predetermined position. At the same time when the reversing movement of the stage 4 is completed, the switching valve 2a-a is switched to the paint suction pipe side to prepare for filling the micro syringe pump 2-a with paint, and at the same time, the switching valve 2a-b is switched to the paint discharge pipe side to switch to the next. Prepare for coating.
[0020]
The above operation was sequentially repeated to form a coating film on 100 sheets of the coating material 8.
The coating film thus obtained did not show cavitation during filling and discharging, and had good film thickness profiles.
On the other hand, when one micro-syringe pump was used and the operating speed of the micro-syringe pump was set to be the same, the same film thickness profile as described above was obtained, but the total required time was significantly longer.
[0021]
In addition, when one micro syringe pump was used and the suction speed was set to 2.5 times to achieve the same tact time, cavitation occurred and a good film thickness profile could not be obtained.
In the above embodiment, the micro syringe pump 2 is exemplified as the piston type metering pump. However, a positive displacement pump such as a plunger type metering pump and a diaphragm type metering pump can be adopted. Types are also included in the piston type displacement pump referred to in the present invention.
[0022]
【The invention's effect】
According to the first aspect of the present invention, since the paint supply operation and the paint suction operation can be performed independently, it is not necessary to increase the paint suction speed, so that the time required for single-wafer coating without impairing the uniformity of the coating film. Can be greatly shortened. The invention of claim 2 has a unique effect that a high-quality color filter can be efficiently created.
[0023]
According to the third aspect of the present invention, since the paint suction operation can be performed in parallel with the paint supply operation, and since it is not necessary to increase the paint suction speed, it is necessary to perform single-sheet coating without impairing the uniformity of the coating film. This has a unique effect that the time can be significantly reduced.
The invention of claim 4 has a unique effect that a high quality color filter can be produced.
[Brief description of the drawings]
FIG. 1 is a view schematically showing an embodiment of a sheet-fed coating apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Paint tank 1a Paint suction pipe 2 Micro syringe pump 2a Switching valve 3 Paint discharge device 3a Slit 3b Paint discharge pipe 4 Stage 7 Computer 8 Color filter board

Claims (4)

The paint is sucked from the paint tank (1) by the piston type metering pump (2) through the first liquid sending line (1a) and the switching valve (2a), and the switching valve (2a) is drawn from the piston type metering pump (2). The suctioned paint is supplied to the paint discharge slit (3a) of the paint discharge device (3) through the second liquid feed pipe (3b), and the workpiece (8) is held by the stage (4). A sheet-fed coating apparatus for applying a coating material on the upper surface of the material to be coated (8) by moving a predetermined position below the coating material discharging device (3) in a direction substantially orthogonal to the coating material discharging direction. The piston type metering pump (2) and the switching valve (2a) are provided at least two each, and between the first liquid sending line (1a) and the second liquid sending line (3b), They are provided in parallel, and these piston type Paint supply by the pump (2), sheets, characterized in that it comprises in order to perform at different timings the paint sucking one another piston-type metering pump (2) and the switching valve control means for controlling the (2a) independently (7) Leaf coating equipment. The sheet-fed coating apparatus according to claim 1, wherein the material to be coated (8) is a substrate for a color filter. The paint is sucked from the paint tank (1) by the piston type metering pump (2) through the first liquid sending line (1a) and the switching valve (2a), and the switching valve (2a) is drawn from the piston type metering pump (2). The suctioned paint is supplied to the paint discharge slit (3a) of the paint discharge device (3) through the second liquid feed pipe (3b), and the workpiece (8) is held by the stage (4). A sheet-fed coating method in which a predetermined position below the paint discharge device (3) is moved in a direction substantially perpendicular to the paint discharge direction to thereby apply paint to the upper surface of the workpiece (8). The piston type metering pump (2) and the switching valve (2a) are provided at least two each, and while one piston type metering pump is supplying the paint, the other piston type metering pump is independently controlled. painted by Suction was performed, or sheet coating method which comprises causing wait for paint supply. The single-wafer coating method according to claim 3, wherein the material to be coated (8) is a substrate for a color filter.

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