JP4133063B2 - Solution coating apparatus and supply method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coating apparatus and a coating method for spray-coating a solution onto a substrate using a nozzle head.
[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 in which a functional thin film such as an alignment film, a resist, a color filter, and organic electroluminescence is formed on a substrate such as a glass substrate or a semiconductor wafer. In this film forming process, a coating apparatus including a nozzle head that sprays and applies a solution by an ink jet method is used to apply the solution.
[0003]
The coating apparatus has a transport table for transporting a substrate, and a plurality of nozzle heads are arranged in parallel above the transport table along a direction intersecting the moving direction of the transport table. Each nozzle head is provided with a nozzle plate in which a plurality of nozzles are perforated, 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 applied to the substrate is replaced with a different type of solution, the solution remaining in the nozzle head or piping must be removed and a new solution must be supplied.
[0005]
Before using a coating apparatus to which a new solution is supplied, it is necessary to degas bubbles in the pipeline through which the solution flows in order to uniformly spray the solution from each nozzle head.
[0006]
Specifically, a liquid supply pipe for supplying a solution to the nozzle head, a space in the nozzle head to which the solution is supplied by the liquid supply pipe, and air bubbles from the nozzles formed in the nozzle head are removed.
[0007]
When the bubbles are removed, the above-described functional thin film is very expensive, and the solution supplied to the nozzle head and the liquid supply pipe is collected using the drainage pipe. The drainage pipe is connected to the nozzle head in parallel with the liquid supply pipe.
[0008]
When bubbles are removed from the nozzle head and the liquid supply pipe, the solution can be sprayed uniformly from the plurality of nozzles formed on the nozzle head toward the substrate, so that the accuracy of application of the solution to the substrate is improved. be able to.
[0009]
[Problems to be solved by the invention]
When a plurality of nozzle heads are connected to the liquid supply pipe, the nozzle head located on the upstream side in the liquid supply direction is more likely to flow the solution than the nozzle head located on the downstream side. As a result, the solution cannot be evenly supplied to the plurality of nozzle heads.
[0010]
In view of this, the diameter of the liquid supply pipe is increased so that the solution can be uniformly supplied to a plurality of nozzle heads. However, when the liquid supply pipe is thickened, the amount of the solution remaining in the liquid supply pipe also increases.
[0011]
By the way, when the nozzle head is repaired or replaced, or when the solution applied to the substrate is replaced with a different type of solution, the solution remaining in the liquid supply pipe is discarded.
[0012]
However, if the pipe diameter of the liquid supply pipe is increased due to the above-described reason, the amount of the solution remaining in the liquid supply pipe increases, so that the amount of the solution to be discarded also increases, resulting in a significant increase in cost. .
[0013]
Moreover, even if the liquid supply pipe is thickened, the plurality of nozzle heads are sequentially connected in parallel along the liquid supply direction to the liquid supply pipe, so that the nozzle head on the upstream side in the liquid supply direction is located on the downstream side. It is inevitable that the solution flows more easily than the nozzle head. As a result, the solution cannot be uniformly supplied to the plurality of nozzle heads, and thus the solution may not be uniformly applied in the width direction of the substrate.
[0014]
The present invention relates to a solution coating apparatus and a coating method capable of supplying a solution almost uniformly to a plurality of nozzle heads connected to the liquid supply pipe without increasing the pipe diameter of the liquid supply pipe. Is to provide.
[0015]
[Means for Solving the Problems]
The invention of claim 1 is a coating apparatus for applying a solution to a plate surface of a substrate conveyed in a predetermined direction.
A liquid supply unit storing the above solution;
One end is connected to this liquid supply part, and the liquid supply pipe to which the solution stored in the liquid supply part is supplied,
A plurality of nozzle heads connected in parallel to each of the liquid supply pipes via liquid supply valves;
A drain pipe to each nozzle head for discharging the solution supplied to the nozzle head from the connected upper Symbol liquid supply pipe in parallel via drainage valve,
A diversion valve for diverting a part of the solution supplied from the liquid supply unit to one end of the liquid supply pipe to the drainage pipe when applying the solution to the substrate;
An inflow valve for allowing the solution diverted to the drainage pipe by the diversion valve to flow into the nozzle head from the other end of the liquid supply pipe;
The liquid supply valve, the drainage valve, and the diversion valve are closed, the inflow valve is opened, and the solution supplied to the liquid supply pipe is caused to flow through the drainage pipe, thereby removing bubbles from the liquid supply pipe and the drainage pipe. And
The liquid supply valve and the drainage valve are opened, the flow dividing valve and the inflow valve are closed, and the solution supplied to the liquid supply pipe is caused to flow through the nozzle head, whereby bubbles are removed from the nozzle head. In the solution applicator.
[0016]
In the invention of claim 2, a return tank for collecting the solution discharged from the nozzle head to the drainage pipe is connected to the drainage pipe,
2. The solution application according to claim 1, wherein the drainage pipe is provided with a closing valve for preventing the solution diverted to the drainage pipe by the diversion valve from flowing into the return tank. In the device.
[0017]
According to a third aspect of the present invention , a plurality of nozzle heads are connected in parallel to a liquid supply pipe to which a solution is supplied from a liquid supply section and a drain pipe supplied to the liquid supply pipe, and the substrate is connected to each of the nozzle heads. In the method of applying the solution by spraying the solution onto the coating method,
Supplying a solution from one end and the other end of the liquid supply pipe when spraying the solution from each nozzle head and applying the solution to the substrate;
Preventing the solution supplied from the liquid supply unit to the liquid supply pipe from flowing to the nozzle head and flowing the liquid to the drain pipe to remove bubbles from the liquid supply pipe and the drain pipe;
In solution method for coating, characterized by comprising a step of performing a bubble purging of the nozzle head of a solution to be supplied to the liquid supply tube to flow into the drain pipe from the nozzle head.
[0018]
According to the present invention, since the solution is supplied from one end and the other end of the supply pipe using the drain pipe used for removing air bubbles from the nozzle head, the supply pipe is not made thick, It becomes possible to supply the solution to the plurality of connected nozzle heads almost evenly.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0020]
FIG. 1 shows a schematic configuration of a solution coating apparatus according to an embodiment of the present invention, and this coating apparatus includes a substrate W transfer apparatus 1. The transport device 1 has a base 2, and a pair of guide rails 3 are provided in parallel at both ends in the width direction of the upper surface of the base 2.
[0021]
A conveyance table 4 is movably provided on the guide rail 3. The transport table 4 is driven to reciprocate along the guide rail 3 by a driving mechanism (not shown). The substrate W is supported on the upper surface of the transfer table 4 by a plurality of support pins 5. The substrate W is, for example, a rectangular glass substrate for a liquid crystal display panel. The substrate W may be a semiconductor wafer.
[0022]
Above the transfer table 4, a plurality of, in this embodiment, three nozzle heads 7 are juxtaposed at predetermined intervals along a direction intersecting the transfer direction of the substrate W. The nozzle head 7 has a main body 7a and a nozzle plate 7b provided on the lower end surface of the main body 7a, and a plurality of nozzles 7c are formed in the nozzle plate 7b at predetermined intervals along a direction intersecting the transport direction of the substrate W. It is installed.
[0023]
Each nozzle head 7 is supplied with a solution for forming a functional thin film such as an alignment film, a resist, a color filter, and organic electroluminescence on the substrate W by the liquid supply device 11 as described above.
[0024]
The liquid supply apparatus 11 has a liquid supply tank 12 as a liquid supply unit. The solution L is stored in the liquid supply tank 12. The liquid level F of the solution L stored in the liquid supply tank 12 is controlled to be equal to or slightly higher than the lower surface of the nozzle plate 7b of the nozzle head 7. Thereby, the solution in the liquid supply tank 12 is supplied to each nozzle head 7 with a pressure due to the difference in height between the liquid surface of the solution L and the nozzle plate 7b, as will be described later.
[0025]
One end of a liquid supply pipe 13 is connected to the bottom of the liquid supply tank 12. From the liquid supply pipe 13, a plurality of liquid supply branch pipes 14 corresponding to the plurality of nozzle heads 7 are branched at a predetermined interval. Each liquid supply branch pipe 14 is connected to each nozzle head 7 via a liquid supply valve 15.
[0026]
An air supply pipe 16 for pressurized gas such as nitrogen is connected to the liquid supply tank 12 via an air supply valve 17. When pressurized gas is supplied from the supply pipe 16 to the supply tank 12 and the solution L in the supply tank 12 is pressurized, the solution is supplied from the supply pipe 13 to the supply branch pipe 14. It can be supplied to a space portion (not shown) in the nozzle head 7 through.
[0027]
The solution supplied to the space of the nozzle head 7 is pressurized by a piezo element (not shown) provided to face each nozzle 7c, and is ejected from the nozzle 7c by an ink jet method. As a result, the solution is applied to the substrate W transported under the nozzle head 7.
[0028]
Each nozzle head 7 is connected to one end of a drain branch pipe 22 provided with a drain valve 21. Each drainage branch pipe 22 is connected to a drainage pipe 23 arranged in parallel with the liquid supply pipe 13.
[0029]
And the liquid supply pipe 13, an intermediate portion of one end of the aforementioned drain pipe 23 is connected by a branch pipe 25 having a diverter valve 24. The other end of the liquid supply pipe 13 and the other end of the drainage pipe 23 are connected by a communication pipe 27 having an inflow valve 26. That is, the one end side middle part and the other end of the liquid supply pipe 13 and the drainage pipe 23 are connected by the diversion valve 24 and the inflow valve 26 to form a closed shape.
[0030]
One end of the drainage pipe 23, that is, the end of the drainage pipe 23 is connected to a return tank 29 via a closing valve 28 rather than a portion where the branch pipe 25 is connected. One end of a return pipe 31 is connected to the bottom of the return tank 29. The other end of the return pipe 31 is connected to the bottom of the liquid supply tank 12 through a return valve 32.
[0031]
As a result, as described later, when the solution L is supplied to each nozzle head 7 and the liquid supply pipe 13 to remove bubbles, the solution L supplied to each nozzle head 7 is stored in the return tank 29, and if necessary. Thus, the liquid can be returned to the liquid supply tank 12.
[0032]
The solution L returned from the return tank 29 is supplied to the liquid supply tank 12 according to the liquid level F of the liquid supply tank 12. Thereby, the liquid level F of the liquid supply tank 12 is maintained at a constant height.
[0033]
Next, a procedure for applying a solution to the substrate W using the application apparatus having the above-described configuration will be described with reference to FIGS.
[0034]
Before applying the solution to the substrate W, the piping system of the liquid supply pipe 13 and the drainage pipe 23, the space in the nozzle head 7 and the bubbles of the nozzle 7c are removed. First, as shown in black in FIG. 2, the liquid supply valve 15, the drain valve 21, the flow dividing valve 24 and the return valve 32 are closed, and the air supply valve 17 and the inflow valve 26 are opened.
[0035]
When the air supply valve 17 is opened, pressurized gas is supplied into the liquid supply tank 12, and the solution L in the liquid supply tank 12 is pressurized. As shown by the arrows in FIG. It is supplied to the tube 13.
[0036]
The solution L supplied to the liquid supply pipe 13 flows to the drainage pipe 23 through the communication pipe 27 and the inflow valve 26, and returns to the return tank 29 through the closing valve 28 provided at one end of the drainage pipe 23. Will be collected. By such a flow of the solution L, bubbles are removed from the liquid supply pipe 13 and the drainage pipe 23.
[0037]
When the air supply pipe 13 and the drain pipe 23 have finished removing air bubbles, the flow dividing valve 24, the inflow valve 26 and the return valve 32 are closed and the other valves are opened as shown in black in FIG. The solution L in the liquid supply tank 12 is pressurized with gas and supplied to the liquid supply pipe 13.
[0038]
The solution L supplied from the liquid supply tank 12 to the liquid supply pipe 13 is diverted to the liquid supply branch pipe 14 connecting the liquid supply pipe 13 and each nozzle head 7 as indicated by arrows in FIG. It flows into the space in the nozzle head 7 through the liquid valve 15.
[0039]
The solution L flowing into the space in the nozzle head 7 flows into the drainage pipe 23 through the drainage valve 21 of the drainage branch pipe 22 together with the bubbles in the nozzle head 7, and is provided in the drainage pipe 23. Return to the return tank 29 through the closed valve 28. Thereby, bubbles can be removed from the spaces in the plurality of nozzle heads 7.
[0040]
A space in the nozzle head 7 communicates with the nozzle 7c. However, since the flow resistance of the solution flowing out from the nozzle 7c is sufficiently larger than the resistance of the solution flowing through the nozzle head 7 and flowing into the drainage pipe 23, the solution does not flow out of the nozzle 7c. It is discharged to the tube 23.
[0041]
On the other hand, when air bubbles are removed from the nozzle 7c, the drain valve 21 provided in the drain branch pipe 22 connected to each nozzle head 7 is closed in the state shown in FIG. As a result, the solution supplied to the space in the nozzle head 7 is ejected from the nozzle 7c without flowing into the drainage pipe 23, so that bubbles can be removed from the nozzle 7c.
[0042]
If air bubbles are removed from each part of the coating apparatus in this way, the solution L is applied to the substrate W. In this case, as shown in FIG. 4, the liquid supply valve 15, the diversion valve 24 and the inflow valve 26 are opened, and the other valves painted black are closed.
[0043]
After the opening / closing state of each valve is set as described above, when the liquid supply tank 12 is opened to the atmosphere by an opening means such as a valve (not shown), the solution L in the liquid supply tank 12 is formed between the liquid surface and the lower surface of the nozzle head 7. The liquid is supplied to the liquid supply pipe 13 by the pressure difference due to the height difference. The solution L supplied to the liquid supply pipe 13 sequentially flows into the nozzle head 7 located on the downstream side from the nozzle head 7 connected to the upstream side of the liquid supply pipe 13 through the liquid supply valve 15.
[0044]
A part of the solution L supplied to the liquid supply pipe 13 is diverted to the drainage pipe 23 through the diversion valve 24, and the other end of the drainage pipe 23 is connected to the downstream end of the liquid supply pipe 13. It flows into the other end of the liquid supply pipe 13 through the inflow valve 26.
[0045]
Then, the solution L that has flowed into the downstream end (the other end) of the liquid supply pipe 13 from the drainage pipe 23 is transferred from the nozzle head 7 connected to the downstream side of the liquid supply pipe 13 to the nozzle head 7 connected to the upstream side. It flows in sequentially.
[0046]
The solution L that has flowed into each nozzle head 7 is directed toward the substrate W by operating the piezoelectric element at a predetermined timing when the substrate W transported by the transport table 4 passes under the nozzle head 7. Sprayed and applied to the plate surface of the substrate W.
[0047]
In this way, by using the drainage pipe 23, the solution L is supplied from both the upstream side and the downstream side of the liquid supply pipe 13 to the plurality of nozzle heads 7 connected to the liquid supply pipe 13. can do.
[0048]
For example, considering the case where three nozzle heads 7 are provided, the solution L is supplied only from the upstream of the liquid supply pipe 13 to the nozzle head 7 connected to the uppermost stream of the liquid supply pipe 13. Only the solution L that has flowed from the drainage pipe 23 to the downstream side of the liquid supply pipe 13 is supplied to the nozzle head 7 connected to the most downstream side of the liquid supply pipe 13. The nozzle head 7 located at the center is supplied with the solution L flowing in from the upstream side of the liquid supply pipe 13 and the solution L flowing in from the downstream side. As a result, the solution L is supplied almost uniformly to the three nozzle heads 7 without being affected by the thickness of the liquid supply pipe 13.
[0049]
That is, the solution L can be supplied almost uniformly to the plurality of nozzle heads 7 connected to the liquid supply pipe 13 regardless of whether the connection to the liquid supply pipe 13 is on the upstream side or the downstream side. Become.
[0050]
Thus, since the solution L can be supplied to each nozzle head 7 almost uniformly without increasing the diameter of the liquid supply pipe 13 and the drainage pipe 23, the liquid supply pipe 13 and the drainage pipe 23 are supplied. The amount of the remaining solution L can be reduced.
[0051]
Therefore, when the nozzle head 7 is repaired and inspected, or the type of the solution L applied to the substrate W is changed, the amount of the solution L remaining in the liquid supply pipe 13 and the drainage pipe 23 can be reduced, so that the disposal The amount of solution produced is also small and economical. In other words, the various solutions L forming the functional thin film are very expensive, but the amount of the expensive solution L discarded can be reduced and used efficiently.
[0052]
In the above embodiment, the case where the three nozzle heads 7 are connected to the liquid supply pipe 13 has been described. However, the number of the nozzle heads 7 is not limited to three, and may be any number, and the number may be a substrate. It also depends on the width dimension of W. Recently, since the substrate W tends to increase in size, several tens of nozzle heads may be arranged in parallel, and the present invention is effective even when the number of nozzle heads 7 is increased.
[0053]
【The invention's effect】
As described above, according to the present invention, when the solution is applied to the substrate, the solution can be supplied from both one end and the other end of the liquid supply pipe by using the drain pipe used for removing bubbles. .
[0054]
Therefore, it is possible to supply the solution almost uniformly to the plurality of nozzle heads without increasing the thickness of the supply pipe or the drain pipe. Therefore, when changing the type of the solution, the amount of the discarded solution is reduced. can do.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a solution coating apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory view when air is vented from a liquid supply pipe and a drain pipe.
FIG. 3 is an explanatory diagram when air is released from a nozzle head.
FIG. 4 is an explanatory diagram when a solution is applied to a substrate.
[Explanation of symbols]
7 ... Nozzle head 12 ... Liquid supply tank (liquid supply part)
13 ... Supply pipe 23 ... Drain pipe 24 ... Branch valve 26 ... Inflow valve

Claims (3)

In a coating apparatus that applies a solution to a plate surface of a substrate conveyed in a predetermined direction,
A liquid supply unit storing the above solution;
One end is connected to this liquid supply part, and the liquid supply pipe to which the solution stored in the liquid supply part is supplied,
A plurality of nozzle heads connected in parallel to each of the liquid supply pipes via liquid supply valves;
A drain pipe to each nozzle head for discharging the solution supplied to the nozzle head from the connected upper Symbol liquid supply pipe in parallel via drainage valve,
A diversion valve for diverting a part of the solution supplied from the liquid supply unit to one end of the liquid supply pipe to the drainage pipe when applying the solution to the substrate;
An inflow valve for allowing the solution diverted to the drainage pipe by the diversion valve to flow into the nozzle head from the other end of the liquid supply pipe;
The liquid supply valve, the drainage valve, and the diversion valve are closed, the inflow valve is opened, and the solution supplied to the liquid supply pipe is caused to flow through the drainage pipe, thereby removing bubbles from the liquid supply pipe and the drainage pipe. And
The liquid supply valve and the drainage valve are opened, the flow dividing valve and the inflow valve are closed, and the solution supplied to the liquid supply pipe is caused to flow through the nozzle head, whereby bubbles are removed from the nozzle head. Solution applicator. A return tank for collecting the solution discharged from the nozzle head to the drain pipe is connected to the drain pipe,
2. The solution application according to claim 1, wherein the drainage pipe is provided with a closing valve for preventing the solution diverted to the drainage pipe by the diversion valve from flowing into the return tank. apparatus. A plurality of nozzle heads are connected in parallel to a liquid supply pipe to which a solution is supplied from a liquid supply section and a drain pipe supplied to the liquid supply pipe, and the solution is sprayed onto the substrate from each nozzle head and applied. In the method of applying the solution
Supplying a solution from one end and the other end of the liquid supply pipe when spraying the solution from each nozzle head and applying the solution to the substrate;
Preventing the solution supplied from the liquid supply unit to the liquid supply pipe from flowing to the nozzle head and flowing the liquid to the drain pipe to remove bubbles from the liquid supply pipe and the drain pipe;
And a step of discharging bubbles from the nozzle head by flowing a solution supplied to the liquid supply pipe from the nozzle head to the drain pipe .

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