JP2004024972A - Solution coating device and air bubble removal method - Google Patents

Abstract

An object of the present invention is to provide an apparatus for applying a solution capable of quickly and surely removing bubbles from a nozzle formed in a nozzle head.
In a coating apparatus for spray-coating a solution onto a plate surface of a substrate,
A nozzle head 13 in which a plurality of nozzles for spraying the solution are formed; a transport table 6 on which the substrate is mounted and which is reciprocally driven with respect to the nozzle head below the nozzle head; When the transfer table is provided, the nozzles of the nozzle head are brought into contact with the opened surfaces to close the nozzles, and an opening for sequentially opening a plurality of closed nozzles as the transfer table moves is formed. A bubble removing member 38 is provided for ejecting the solution from the nozzles opened by the openings to remove bubbles in the nozzles.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a coating apparatus for spraying a solution onto a plate surface of a substrate from a nozzle to apply the solution, and a bubble removing method for removing bubbles from the nozzle.
[0002]
[Prior art]
For example, in a manufacturing process of a liquid crystal display device or a semiconductor device, there is a film forming process of forming a functional thin film such as an alignment film, a resist, a color filter, and organic electroluminescence on a substrate such as a glass substrate or a semiconductor wafer. In this film forming process, a coating apparatus provided with a nozzle head for spray-coating the solution by an inkjet method to apply the solution is used.
[0003]
The coating apparatus has a transfer table for transferring a substrate, and a plurality of nozzle heads are arranged above the transfer table in a direction perpendicular to the moving direction of the transfer table. Each nozzle head is provided with a nozzle plate provided with a plurality of nozzles, and a solution supplied to the nozzle head is pressurized and ejected from each nozzle by a piezo element.
[0004]
When the nozzle head is repaired or replaced, or when the solution is replaced with a different type of solution, the supply pipe for supplying the solution to the nozzle head, the inside of the nozzle head to which the solution is supplied by the supply pipe, and the nozzle Bubbles are removed by removing bubbles from each part of the nozzle formed in the head.
[0005]
By removing air bubbles from each part, the solution can be reliably and uniformly sprayed from the plurality of nozzles formed in the nozzle head toward the substrate, so that the accuracy of applying the solution to the substrate is improved. be able to.
[0006]
Usually, a plurality of nozzle heads are provided in the coating apparatus in one or two rows in a direction perpendicular to the moving direction of the transfer table, and each nozzle head is formed with several tens of nozzles. Therefore, the number of nozzles reaches hundreds in the entire coating apparatus.
[0007]
Degassing of the inside of the supply pipe and the nozzle head is performed by supplying the solution from the supply pipe to the nozzle head and returning the solution to a return pipe connected to the nozzle head. In such a case, the nozzle formed in the nozzle head may be closed, but even if the nozzle is not closed, the nozzle hole has a small diameter and the flow path resistance is extremely high as compared with other portions, so that the solution flows from the nozzle hole. No spills.
[0008]
When removing air bubbles from the nozzle, the valve provided on the return pipe is closed, the solution is supplied from the supply pipe to the nozzle head, and the solution is ejected from the nozzle.
[0009]
[Problems to be solved by the invention]
By the way, since the coating apparatus has a plurality of nozzle heads as described above and each nozzle head is formed with several tens of nozzles, the total number of nozzles is considerably large. Therefore, even if the solution is supplied to the nozzle head and is to be ejected from the nozzles, it is difficult for the solution to be ejected uniformly from all the nozzles, and it takes a considerable time until the solution is ejected from all the nozzles. As a result, it is not possible to quickly remove the air bubbles from all the nozzles, so that not only the work efficiency is poor, but also the amount of the solution used during that time becomes considerably large.
[0010]
Since many solutions for forming a functional thin film on a substrate are expensive, an increase in the amount of the solution used for removing bubbles causes a significant increase in cost.
[0011]
Therefore, the solution used for removing bubbles is collected and applied to a substrate for reuse. However, the solution used for removing air bubbles may become dirty or its performance may be deteriorated due to oxidation or the like due to contact with the atmosphere. Therefore, when reused, defective products may be generated. Therefore, it is desired to be able to reliably remove bubbles from the nozzle with a small amount of solution in a short time.
[0012]
It is an object of the present invention to provide a coating apparatus and a bubble removing method which can reliably remove bubbles from these nozzles with a small amount of solution in a short time even if the number of nozzles is large.
[0013]
[Means for Solving the Problems]
The invention according to claim 1 is a coating apparatus which spray-coats a solution on a plate surface of a substrate,
A nozzle head formed with a plurality of nozzles for injecting the solution,
A transfer table on which the substrate is placed and which is reciprocally driven with respect to the nozzle head below the nozzle head,
When the transfer table is driven and the transfer table is driven, the nozzles of the nozzle head come into contact with the open surfaces of the nozzles to close the nozzles, and the plurality of closed nozzles are sequentially opened as the transfer table moves. An opening is formed, and a bubble removing member that ejects a solution from a nozzle opened by the opening to remove bubbles in the nozzle,
A solution application device characterized by comprising:
[0014]
The invention according to claim 2 is characterized in that the bubble removing member has a first closing portion that closes all nozzles before opening the nozzle by the opening, and a nozzle that is opened by the opening and sprays a solution. 2. The solution applying apparatus according to claim 1, further comprising a second closing portion that is sequentially closed.
[0015]
According to a third aspect of the present invention, the supply pipe for the solution is connected to the nozzle head, and the supply of the solution to the nozzle head by the supply pipe is performed by all the nozzles by the first closing portion of the bubble removing member. 3. The solution applying apparatus according to claim 2, wherein the apparatus is started when the nozzle is closed, and is stopped when all the nozzles are closed by the second closing part.
[0016]
According to a fourth aspect of the present invention, there is provided the solution applying apparatus according to the first aspect, wherein the bubble removing member is provided so as to be able to approach and separate from a surface of the nozzle head where the nozzle is opened.
[0017]
According to a fifth aspect of the present invention, there is provided the solution coating apparatus according to the first aspect, wherein the transport table is provided with heating means for heating the substrate.
[0018]
The invention according to claim 6 is a method for removing bubbles from a plurality of nozzles formed in a nozzle head for injecting a solution onto a substrate,
A first closing step of closing all of the plurality of nozzles;
After closing all the nozzles, a supply step of supplying a solution to the nozzle head,
A degassing step of sequentially opening a plurality of nozzles and injecting a solution from the opened nozzles to remove bubbles,
A second closing step of sequentially closing the nozzles onto which the solution has been injected,
The method for removing air bubbles is characterized by comprising:
[0019]
According to the present invention, since the plurality of nozzles provided in the nozzle head are closed and then sequentially opened, the solution can be reliably ejected from the opened nozzles. Can be reliably ejected from all the nozzles in a relatively short time to remove bubbles.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
FIGS. 1 to 6 show a coating apparatus 1 according to a first embodiment of the present invention. The coating apparatus 1 has a rectangular parallelepiped base 2. Legs 3 whose height can be adjusted are provided at a plurality of locations on the lower surface of the base 2, and the legs 3 can support the base 2 horizontally.
[0022]
At both ends in the width direction of the upper surface of the base 2, mounting plates 4 are provided along the longitudinal direction. A guide rail 5 is provided on the upper surface of each mounting plate 4 over substantially the entire length in the longitudinal direction. A transport table 6 is provided on the pair of guide rails 5 so as to be slidable by a slider 7. The transport table 6 is reciprocally driven along the guide rail 5 by a driving device (not shown). A substrate W such as a glass substrate or a semiconductor wafer is detachably mounted on the upper surface of the transfer table 6 by holding means such as support pins 8.
[0023]
A gate-shaped support 11 is provided upright on the middle of the base 2 in the longitudinal direction so as to straddle the pair of guide rails 5. As shown in FIG. 2, a mounting member 12 is provided on the support 11 along the width direction. A plurality of ink jet type nozzle heads 13 are provided on one side surface of the mounting member 12 in one or two rows, and in this embodiment, in one row.
[0024]
As shown in FIGS. 5A and 5B, the nozzle head 13 has a head body 14, and a nozzle plate 15 is provided on a lower end surface of the head body 14. The nozzle plate 15 is provided with a plurality of nozzles 16 in a staggered manner.
[0025]
A piezo element (not shown) is provided in the head main body 14 at a position facing each nozzle 16. By driving the piezo element, the solution supplied to the head main body 14 by a supply pipe 21 described below is supplied. The liquid is sprayed from the nozzle 16 toward the substrate W held on the transfer table 6.
[0026]
As the solution, a solution that forms a functional thin film such as an alignment film, a resist, a color filter, and organic electroluminescence on the substrate W is used.
[0027]
One end of a solution supply pipe 21 and one end of a recovery pipe 22 are connected to the head body 14 of the nozzle head 13 as shown in FIG. On-off valves 23 and 24 are provided on the supply pipe 21 and the recovery pipe 22.
[0028]
The other end of the supply pipe 21 is connected to a solution supply tank 25. The other end of the collection pipe 22 is connected to a collection tank 26. The collection tank 26 and the supply tank 25 are connected by a supply pipe 28 provided with an on-off valve 27 in the middle.
[0029]
The supply tank 25 and the recovery tank 26 are provided with level sensors 25a and 26a for detecting the level of the solution. When the liquid level of the recovery tank 26 becomes lower than a predetermined level, the solution is replenished by a replenishing pipe 31 having an on-off valve 29 connected to the recovery tank 26. When the liquid level in the supply tank 25 falls below a predetermined level, a solution is supplied to the supply tank 25 from the recovery tank 26.
[0030]
The supply pipe 21 and the recovery pipe 22 are branched according to the number of the nozzle heads 13, and are connected to the respective nozzle heads 13 via on-off valves 23 and 24.
[0031]
As shown in FIG. 4, a guide member 33 is provided on one end surface of the transfer table 6 along the vertical direction. A slider 35 provided on one side of a movable member 34 having an L-shaped cross section is slidably engaged with the guide member 33. That is, the movable member 34 is provided so as to be vertically movable along the guide member 33. The movable member 34 is vertically driven by a cylinder 36 as a driving means provided on one side surface of the transfer table 6.
[0032]
The other side of the movable member 34 is substantially horizontal. On the upper surface of the other side, an air bubble removing member 38 formed in a rectangular plate shape by an elastic material such as rubber or fluorine resin is provided.
[0033]
When the movable member 34 is raised by the cylinder 36 as shown by a dashed line in FIG. 4, the upper surface of the bubble removing member 38 has a height at which the plurality of nozzle heads 13 provided on the mounting member 12 are in close contact with the nozzle plate 15. To rise.
[0034]
As shown in FIG. 6A, the bubble removing member 38 has a plurality of openings 39 corresponding to the plurality of nozzle heads 13 arranged in parallel. In this embodiment, the opening 39 is formed of a linear slit, and is inclined at a predetermined angle θ with respect to a direction orthogonal to the traveling direction of the transport table 6 indicated by an arrow X in FIG.
[0035]
When the transport table 6 travels in the direction of the arrow X in a state where the bubble removing member 38 has risen to a predetermined height, the bubble removing member 38 first has one end in the width direction along the X direction. 13 nozzle plate 15.
[0036]
One end of the bubble removing member 38 in the width direction along the X direction is connected to a first closing portion 38a having a width Z larger than the size of the staggered nozzle 16 indicated by Y in FIG. The other end is also formed in the second closing portion 38b having the same width dimension Z.
[0037]
When the bubble removing member 38 moves in the direction of the arrow X from the position of FIG. 6A to the position of FIG. 6B due to the traveling of the transfer table 6, all the nozzles 16 of each nozzle head 13 are closed by the first blockage. It is closed by the portion 38a.
[0038]
When the bubble removing member 38 further moves in the X direction from the position shown in FIG. 6B as shown in FIG. 6C, the nozzle plate 15 is opened facing one of the nozzles 16 at one longitudinal end of the nozzle plate 15 in order. Is done.
[0039]
When the nozzles 16 at the other end in the longitudinal direction of the nozzle plate 15 are completely opened, all the nozzles 16 are closed by the second closing portion 38b at the other end of the bubble removing member 38 along the X direction. The contact state with the punching member 38 is released.
[0040]
As shown in FIGS. 1 and 4, a recovery pan 41 is provided integrally with the transfer table 6 below the bubble removing member 38 on the other side of the movable member 34. The collecting pan 41 collects a solution ejected from a nozzle and passing through an opening 39 and a through-hole (not shown) formed on the other side of the movable member 34 as described later.
[0041]
The transfer table 6 has a built-in heater 42 as heating means for heating the substrate W supported on the upper surface by the support pins 8. The heater 42 does not evaporate the solvent of the solution supplied to the substrate W, and further reduces the viscosity of the solution sprayed on the upper surface of the substrate W to such a degree as to flow smoothly on the upper surface of the substrate W, for example, 30 to The substrate W is controlled to be heated to 40 ° C.
[0042]
Next, a procedure for removing bubbles before applying the solution to the substrate W by the coating apparatus 1 having the above configuration will be described with reference to FIGS.
[0043]
When the solution is replaced with a different one, or when the nozzle head 13 is repaired or replaced, bubbles may remain in the inside of the nozzle head 13 or the nozzle 16, so that the bubbles must be removed. In order to remove bubbles, first, the solution in the supply tank 25 is supplied from the supply pipe 21 to the nozzle head 13, and is collected from the collection pipe 22 to the collection tank 25, and stays in the supply pipe 21 and the nozzle head 13. Bubbles can be removed by the flow of the solution.
[0044]
When the bubble removal of the nozzle head 13 is completed, the bubble removal of the nozzle 16 provided on the nozzle plate 15 is performed. To remove bubbles from the nozzle 16, first, the bubble removing member 38 is raised to a height that closely contacts the nozzle plate 15, and then the transport table 6 is caused to travel toward the nozzle head 13. When the bubble removing member 38 reaches below the nozzle head 13 from the state shown in FIG. 6A as shown in FIG. 6B, the bubble removing member 38 is moved to one end in the width direction of the bubble removing member 38 along the carrying direction of the carrying table 6. All the nozzles 16 of each nozzle head 13 are closed by the formed first closing portion 38a.
[0045]
When all the nozzles 16 are closed, the supply of the solution to the nozzle head 13 through the supply pipe 21 is started. At this time, since all the nozzles 16 are closed by the first closing portions 38a of the bubble removing member 38, the solution is not ejected from the nozzles 16 and the pressure increases in the nozzle head 13.
[0046]
When the bubble removing member 38 is further moved in the direction of arrow X as shown in FIG. 6C from the state where the first closing portions 38a of the bubble removing member 38 block all the nozzles 16, the length of each nozzle plate 15 becomes longer. The nozzles 16 at one end in the direction are sequentially opened facing the opening 39. As a result, the solution is jetted from the opened nozzle 16, so that the bubble is removed from the nozzle 16.
[0047]
When the bubble removing member 38 is further moved in the X direction from the state shown in FIG. 6C, all the nozzles 16 are sequentially opened facing the opening 39, so that the bubbles are sequentially removed from the opened nozzles 16. Will be done.
[0048]
When all the nozzles 16 have been vented in this way, as shown in FIG. 6D, all the nozzles 16 are closed by the second closing portions 38b of the air vent member 38. By stopping the supply of air bubbles, the air bubble removal of the nozzle 16 ends.
[0049]
As described above, the bubble removing member 38 is moved, the plurality of nozzles 16 are sequentially opened to face the opening 39, and the solution is sprayed from the opened nozzle 16 to remove bubbles.
[0050]
Therefore, by providing a plurality of nozzle heads 13, even if the number of nozzles 16 is increased, all of the nozzles 16 are opened one by one to remove air bubbles. It can be sprayed quickly to remove bubbles.
[0051]
In other words, when the number of nozzles 16 increases, if the solution is simultaneously ejected from all the nozzles 16 to remove bubbles, the solution cannot be ejected from the nozzle 16 having a large resistance reliably and quickly. As the time required for removing air bubbles increases, the amount of solution used also increases.
[0052]
However, according to the present invention, after all of the many nozzles 16 are closed as described above, the nozzles 16 are sequentially opened one by one to remove air bubbles. Therefore, it is possible to reliably remove bubbles from all the nozzles 16 in a short time, thereby reducing the amount of the solution used.
[0053]
Before the nozzle 16 is opposed to the opening 39, the air bubble removing member 38 has a first closed portion 38a for closing all the nozzles 16 and all the nozzles 16 are opposed to the opening 39 to remove air bubbles. The second closing portion 38b for closing all of the nozzles 16 is provided.
[0054]
By providing the first closing portion 38a, the solution is not ejected from the nozzle 16 before facing the opening portion 39, so that the solution can be prevented from being wastefully used. By providing the second closing portion 38b, the solution is not ejected again from the nozzle 16 which has faced the opening 39 and the solution has been ejected. Not only can be reliably injected, but also the solution can be prevented from being unnecessarily injected.
[0055]
When the solution is applied to the substrate W by the coating apparatus 1 in which the air bubbles have been removed in this manner, the transport table 6 is driven by lowering the air bubble removing member 38 to a height not in contact with the nozzle plate 15. When the substrate W is transported below the nozzle heads 13, the solution is sprayed onto the substrate W from the nozzles 16 of each nozzle head 13.
[0056]
The substrate W is heated by the heater 42 provided on the transfer table 6 to a predetermined temperature, that is, a temperature at which the solvent in the solution does not evaporate and the fluidity is not impaired. Therefore, the solution sprayed on the plate surface of the substrate W flows with reduced viscosity and becomes smooth on the plate surface of the substrate W, so that the functional thin film formed by the solution can have a uniform thickness. It becomes.
[0057]
Conventionally, in order to reduce the viscosity of the solution, it has been practiced to heat the solution to a predetermined temperature in the supply tank 25 in advance. However, when the solution is heated in the supply tank 25, the time from when the solution is heated to when it is ejected from the nozzle 16 of the nozzle head 13 is often long, and during this time, the solution is oxidized and deteriorates. That was not desirable.
[0058]
However, by providing the heater 42 on the transfer table 6 to heat the substrate W, the heating time until the solution is preliminarily baked can be shortened, so that deterioration due to oxidation or the like can be suppressed.
[0059]
The present invention is not limited to the first embodiment. For example, in the first embodiment, the number of openings 39 corresponding to the number of the nozzle heads 13 is formed in the bubble removing member 38, but one opening 39A is provided for two nozzle heads 13 as shown in FIG. Alternatively, one opening 39A may be formed for three or more nozzle heads 13 (not shown).
[0060]
If the opening 39 is made to correspond to a plurality of nozzle heads 13, the number of nozzles 16 that are opened at a time is reduced, so that the solution can be more rapidly and reliably ejected from the opened nozzles 16. Become.
[0061]
The coating apparatus 1 may be provided with the nozzle heads 13 in two rows as shown in FIG. Even in such a case, for example, by forming the openings 39B in two rows in the bubble removing member 38 so as to correspond to the respective nozzle heads 13, the bubble removing of the nozzle 16 can be performed similarly to the first embodiment. Can be performed.
[0062]
In this case, although not shown in detail, the opening 39 may have a shape corresponding to the plurality of nozzle heads 13.
[0063]
The shape of the opening 39 formed in the bubble removing member 38 is not limited to a linear shape, and may be a stepped opening 39C shown in FIG. 9 or a V-shaped opening D shown in FIG. Any shape may be used as long as the bubble removing member 38 moves while contacting the nozzle head 13 so that the plurality of nozzles 16 can be sequentially opened.
[0064]
【The invention's effect】
As described above, according to the present invention, a plurality of nozzles provided in a nozzle head are closed and sequentially opened, and a solution is ejected from the opened nozzles to remove bubbles from the nozzles.
[0065]
Therefore, even if the number of nozzles is large, the solution can be ejected from all the nozzles reliably and in a relatively short time to remove bubbles, so that the solution used for removing bubbles can be reduced. it can.
[Brief description of the drawings]
FIG. 1 is a side view of a coating apparatus according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of the coating apparatus of FIG.
FIG. 3 is a piping diagram for supplying a solution to a nozzle head.
FIG. 4 is an enlarged view of an end of the transfer table provided with a bubble removing member.
5A is a front view of a nozzle head, and FIG. 5B is a bottom view of the nozzle head showing a nozzle plate.
6A is an explanatory diagram of a state before the bubble removing member contacts the nozzle head, FIG. 6B is an explanatory diagram of a state in which all nozzles are closed by a first closing portion of the bubble removing member, (C) is an explanatory view of a state in which a part of the nozzle is exposed to the opening, and (d) is an explanatory view of a state in which all nozzles are closed by a second closing portion of the bubble removing member.
FIG. 7 is a plan view showing a modified example of the bubble removing member of the present invention.
FIG. 8 is a plan view showing a modification of the arrangement state of the nozzle heads.
FIG. 9 is a plan view showing a modification of the opening formed in the bubble removing member.
FIG. 10 is a plan view showing still another modified example of the opening formed in the bubble removing member.
[Explanation of symbols]
6 ... Transfer table 13 ... Nozzle head 16 ... Nozzle 21 ... Supply pipe 38 ... Bubble removing member 39 ... Opening 42 ... Heater (heating means)

Claims (6)

In a coating apparatus that spray-coats a solution on a plate surface of a substrate,
A nozzle head formed with a plurality of nozzles for injecting the solution,
A transfer table on which the substrate is placed and a reciprocating drive is performed on the nozzle head below the nozzle head,
When the transfer table provided on the transfer table is driven, the nozzles of the nozzle head come into contact with the open surfaces of the nozzles to close the nozzles, and the plurality of closed nozzles are sequentially opened as the transfer table moves. An opening is formed, and a bubble removing member that ejects a solution from a nozzle opened by the opening to remove bubbles in the nozzle,
A solution coating device, comprising: The bubble removing member has a first closing portion that closes all nozzles before opening the nozzles by the opening portion, and a second closing portion that sequentially closes the nozzles that are opened by the opening portions and spray the solution. The apparatus for applying a solution according to claim 1, further comprising a unit. The solution supply pipe is connected to the nozzle head, and the supply of the solution to the nozzle head by the supply pipe is started when all the nozzles are closed by the first closing portion of the bubble removing member. 3. The solution applying apparatus according to claim 2, wherein the apparatus is stopped when all the nozzles are closed by the second closing section. 2. The solution applying apparatus according to claim 1, wherein the bubble removing member is provided so as to be able to contact and separate from a surface of the nozzle head where the nozzle is opened. 2. The solution applying apparatus according to claim 1, wherein the transport table is provided with a heating unit for heating the substrate. In a method for removing air bubbles from a plurality of nozzles formed in a nozzle head for injecting a solution onto a substrate,
A first closing step of closing all of the plurality of nozzles;
After closing all the nozzles, a supply step of supplying a solution to the nozzle head,
A degassing step of sequentially opening a plurality of nozzles and injecting a solution from the opened nozzles to remove bubbles,
A second closing step of sequentially closing the nozzles onto which the solution has been injected,
A method for removing air bubbles, comprising:

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