JP4537657B2 - Solution coating apparatus and bubble removal method of coating apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coating apparatus that sprays a solution from a nozzle and applies the solution to a substrate, and a method for removing bubbles from the coating apparatus.
[0002]
[Prior art]
In general, a manufacturing process of a liquid crystal display device or a semiconductor device includes a film forming process for forming a circuit pattern on a substrate such as a glass substrate or a semiconductor wafer. In this process, a functional thin film such as an alignment film or a resist is formed on the plate surface of the substrate.
[0003]
In the case of forming a functional thin film on a substrate, an ink jet type coating apparatus is used in which a solution for forming the functional thin film is sprayed from a nozzle and applied to the plate surface of the substrate. This coating apparatus has a transport table for transporting the substrate, and a plurality of heads with the nozzles formed above the transport table are arranged in parallel along a direction substantially perpendicular to the transport direction of the substrate. Has been. Each head is supplied with a solution from a solution tank connected via a supply pipe.
[0004]
As a result, the solution is sprayed and applied from the nozzles to the upper surfaces of the plurality of substrates that are sequentially conveyed at a predetermined interval. The solution supplied to the head can be recovered through a recovery pipe connecting the head and the solution tank.
[0005]
When a solution is applied to a substrate using an ink jet type coating apparatus, the solution may not be properly ejected from the nozzle if bubbles are accumulated in the supply pipe or the nozzle. Therefore, before using the coating device, the solution is supplied from the solution tank to the supply pipe at a high pressure, and is collected through the head into the collection pipe, thereby removing the bubbles from the supply pipe, the head, and the collection pipe. Further, the solution supplied from the supply pipe to the head is ejected from the nozzle without returning to the recovery pipe, thereby removing the bubbles from the nozzle.
[0006]
[Problems to be solved by the invention]
Since a solution for forming a functional thin film such as an alignment film is very expensive, the solution must not be wasted by removing bubbles. However, when air bubbles are extracted from the supply pipe, the head, and the recovery pipe, there is a case where the solution flows out from a nozzle formed on the head when the solution is flowed to the head and recovered in the recovery pipe.
[0007]
It is conceivable that the solution flowing out from the nozzle is recovered and used. However, when a solution for forming a functional thin film such as an alignment film comes into contact with the atmosphere, the performance may deteriorate due to reaction with oxygen or moisture contained in the atmosphere. For this reason, there is a case where a solution that is ejected from a nozzle and comes into contact with the atmosphere during bubble removal cannot be used.
[0008]
On the other hand, in the case where the bubbles are removed from the nozzle, the pressure in the head is increased so as not to return the solution supplied to the head to the recovery tube, so that the diameter formed on the head is several μm. It is made to spray from a nozzle.
[0009]
As described above, a large number of small nozzles are formed on the head. Therefore, even if the solution supplied to the head is prevented from returning to the recovery pipe and the pressure is increased, it is possible to avoid nozzles that are easy to flow and nozzles that are difficult to flow depending on the position formed on the head. Absent.
[0010]
For this reason, it is difficult not only to eject bubbles from all nozzles to reliably remove bubbles, but also to spray solutions from nozzles where the solution does not flow easily, Must continue to supply. As a result, the amount of the solution ejected from the nozzle at a position where the solution can easily flow is increased more than necessary, and the amount of the solution used for defoaming the nozzle may increase.
[0011]
It is an object of the present invention to provide a solution coating apparatus and a coating method which can be performed without causing a solution to flow out from a nozzle when bubbles are extracted from a supply tube, a head and a recovery tube.
[0012]
The present invention provides a solution coating apparatus and a coating method in which a solution can be ejected relatively easily from a nozzle in a position where it is difficult for the solution to flow when bubbles are removed from a nozzle formed in a head. It is to provide.
[0014]
[Means for Solving the Problems]
The present invention provides a coating apparatus for spray-coating a solution on a substrate.
A head having a nozzle for ejecting the solution by an inkjet method;
A source of the solution;
A supply pipe for connecting the supply source and the head and supplying the solution of the supply source to the head;
When the nozzle of the head is pressed against the surface on which the nozzle is formed, the nozzle can be closed, and when the solution supplied under pressure to the head from the supply source through the supply pipe is ejected from the nozzle And a sealing member that repeatedly opens and closes the nozzle so as to pulsate the pressure of the solution supplied from the supply source and flowing into the head.
[0015]
The present invention provides a coating apparatus for spray-coating a solution on a substrate.
A head having a nozzle for ejecting the solution by an inkjet method;
A source of the solution;
A supply pipe that connects the supply source and the head and is provided with a supply opening / closing valve and supplies the solution of the supply source to the head in response to opening / closing of the supply opening / closing valve;
The supply opening / closing is performed so as to pulsate the pressure of the solution supplied by pressure from the supply source and flowing into the head when the solution pressurized to the head through the supply pipe is sprayed from the nozzle. A solution coating apparatus characterized by repeatedly opening and closing a valve.
[0016]
The sealing member is preferably a wiping member that opens and closes the nozzle by reciprocating along the lower surface of the head with the upper end in contact with the lower surface of the head.
[0018]
The present invention relates to a coating apparatus having a head having a nozzle for ejecting a solution by an ink jet method and a supply pipe for supplying the solution to the head, wherein the bubble is removed from the nozzle prior to use. In
The pressure of the solution that is pressurized and supplied from the supply source and flows through the head when the air bubbles are discharged from the nozzle of the head by discharging the solution that is pressurized and supplied to the head through the supply pipe. Of the coating apparatus, wherein the sealing member capable of closing the nozzle by pressing the nozzle against the surface on which the nozzle of the head is formed is moved up and down to repeatedly open and close the nozzle, thereby causing pulsation. It is in the bubble removal method.
[0019]
According to this invention, by supplying the solution from the supply pipe to the head and flowing it to the recovery pipe and collecting it, when removing the bubbles from the supply pipe, the head and the recovery pipe, the nozzle of the head is hermetically sealed. The solution is prevented from flowing out.
[0020]
According to the present invention, when bubbles are removed from the nozzle, the solution flowing through the head is pulsated, so that the solution can be ejected relatively easily from the nozzle at a position where the solution is difficult to flow.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
[0022]
The solution coating apparatus according to the present invention shown in FIGS. A pair of rails 2 spaced apart from each other at a predetermined interval are laid along the longitudinal direction of the base 1 on the upper surface of the base 1. The rail 2 is provided with a transport table 3 so as to be able to travel, and is driven to travel by a drive source (not shown). A large number of support pins 4 are provided on the upper surface of the transport table 3, and a glass substrate W used for, for example, a liquid crystal display device is supplied and supported on these support pins 4.
[0023]
Above the substrate W driven together with the transfer table 3, a plurality of heads for spraying and applying a solution for forming a functional thin film on the substrate W by an inkjet method, in this embodiment, three heads 7 are substrates. It is arranged in a line along the direction intersecting the traveling direction of W.
[0024]
The head 7 includes a head body 8 as shown in FIG. The head body 8 is formed in a cylindrical shape, and its lower surface opening is closed by a flexible plate 9. The flexible plate 9 is covered with a nozzle plate 11, and a liquid chamber 12 is formed between the nozzle plate 11 and the flexible plate 9.
[0025]
A liquid supply hole 13 communicating with the liquid chamber 12 is formed at one longitudinal end of the head body 8. From the liquid supply hole 13, a solution for forming a functional thin film such as an alignment film or a resist is supplied to the liquid chamber 12. Thereby, the inside of the liquid chamber 12 is filled with the solution.
[0026]
As shown in FIG. 4, a plurality of nozzles 14 are formed in the nozzle plate 11 in a zigzag pattern along a direction orthogonal to the transport direction of the substrate W. A plurality of piezoelectric elements 15 are provided on the upper surface of the flexible plate 9 so as to face the nozzles 14 as shown in FIG.
[0027]
Each piezoelectric element 15 is supplied with a driving voltage by a driving unit 16 provided in the head body 8. As a result, the piezoelectric element 15 expands and contracts and partially deforms the flexible plate 9, so that the solution is sprayed and applied to the upper surface of the substrate W to which the solution is conveyed from the nozzle 14 facing the piezoelectric element 15.
[0028]
As shown in FIG. 3, a recovery hole 17 communicating with the liquid chamber 12 is formed at the other longitudinal end of the head body 8. The solution supplied from the liquid supply hole 13 to the liquid chamber 12 can be recovered from the recovery hole 17. That is, the head 7 can not only eject the solution supplied to the liquid chamber 12 from the nozzle 14 but also collect the solution from the recovery hole 17 through the liquid chamber 12.
[0029]
As shown in FIG. 1, a supply branch pipe 22 branched from a solution supply pipe 21 is connected to the liquid supply hole 13 of each head 7, and a recovery branch pipe 24 branched from a recovery pipe 23 to the recovery hole 17. Is connected. The supply branch pipe 22 is provided with a supply on / off valve 25, and the recovery branch pipe 24 is provided with a recovery on / off valve 26. The tips of the supply pipe 21 and the recovery pipe 23 are connected via a communication valve 27. Further, the recovery pipe 23 is provided with a main recovery valve 28 at a portion closer to the base end than the recovery branch pipe 24.
[0030]
The base end of the supply pipe 21 is connected to the bottom of the solution tank 31 in which the solution L is stored. The proximal end of the recovery pipe 23 is connected to a storage tank 32 that stores the solution L supplied to the solution tank 31. A supply branch pipe 34 having a supply valve 33 is branched from the base end portion of the recovery pipe 23, and the supply branch pipe 34 is connected to the bottom of the solution tank 31.
[0031]
An air release pipe 35 is connected to the upper part of the solution tank 31. The atmosphere opening pipe 35 is provided with a first opening / closing control valve 36. When the first opening / closing control valve 36 is opened, the inside of the solution tank 31 is communicated with the atmosphere. The atmosphere release pipe 35 communicates with the atmosphere via a processing device (not shown) for processing the vaporized solvent contained in the gas diffused from the atmosphere release pipe 35 to the atmosphere. Therefore, the gas flowing through the atmosphere release pipe 35 receives resistance.
[0032]
A gas supply pipe 38 provided with a second opening / closing control valve 37 is connected to the upper part of the solution tank 31. The gas supply pipe 38 is supplied with an inert gas such as nitrogen from a gas supply source (not shown).
[0033]
A filter 39 and a third opening / closing control valve 40 are sequentially connected to the gas supply pipe 38 upstream of the second opening / closing control valve 37. The third open / close control valve 40 is provided with a flow restrictor 41 in parallel. This flow restrictor 41 and the third on-off control valve 40 constitute gas flow control means.
[0034]
An atmosphere release pipe 44 having a fourth open / close control valve 43 is connected to the upper portion of the storage tank 32, similarly to the solution tank 31. Further, a gas supply pipe 46 having a fifth opening / closing control valve 45 is connected. A filter 47 and a sixth open / close control valve 48 are sequentially connected to the gas supply pipe 46. The sixth open / close control valve 48 is provided with a flow restrictor 49 in parallel.
[0035]
The supply on / off valve 25, the recovery on / off valve 26, the main recovery valve 28, the supply valve 33, and the first to sixth on / off control valves 36, 37, 40, 43, 45, and 48 are opened and closed by a control device (not shown). To be controlled. Further, the liquid level of the solution L in the solution tank 31 is detected by the level sensor 50. When the level sensor 50 detects that the liquid level of the solution L has become below a predetermined level, the solution L is replenished from the storage tank 32 based on the detection. That is, the solution L in the storage tank 32 is pressurized by the inert gas supplied through the fifth open / close control valve 45, so that the solution L is supplied to the solution tank 31.
[0036]
As shown in FIG. 2, an attachment member 51 having an L-shaped side surface is provided on one end face of the transport table 3 with one vertical side fixed to the end face of the transport table 3. On the other horizontal side of the mounting member 51, an upper and lower cylinder 52 is provided with the axis line vertical.
[0037]
An upper / lower table 54 is attached to the rod of the upper / lower cylinder 52 via an elastic member 53. On the upper surface of the upper and lower tables 54, three pressing members 55 as sealing members made of an elastic material such as a blade-like rubber having a length corresponding to each head 7 are held by the holding members 56 so as to be displaced in the vertical direction. ing. Each pressing member 55 is elastically biased in the upward direction by a spring 57 provided on the holding member 56. The holding member 55 has a width dimension and a thickness dimension so that the entire nozzle 14 formed in a staggered pattern on the head 7 can be closed at the upper end surface thereof.
[0038]
The upper and lower tables 54 are provided with a wiping member 58 formed of an elastic material such as a blade-like rubber in parallel with the pressing member 55. The upper end of the wiping member 58 is positioned above the upper end of the pressing member 55 by a predetermined dimension.
[0039]
The upper and lower tables 54 are provided on the inner bottom of the collection tank 61. A guide plate 62 is provided on one side of the collection tank 61, and a guide member 63 is provided on the guide plate 62. The guide member 63 can be moved up and down by being guided by a guide rail 64 provided on the end surface of the transfer table 3 along the vertical direction.
[0040]
Accordingly, when the upper and lower cylinders 52 are driven, the upper and lower tables 54 are driven, and the guide plate 62 moves up and down along the guide rails 64, so that the upper and lower tables 54 are restricted from swinging in the front and rear and right and left directions. Moved up and down.
[0041]
A collection tank 65 shown in FIG. 1 is connected to the collection tank 61. The recovery tank 65 recovers the solution sprayed from the nozzle 14 to the recovery tank 61 when the bubbles of the nozzle 14 of the head 7 are removed.
[0042]
Next, a procedure for degassing the supply pipe 21, the head 7, the recovery pipe 23, and the nozzle 14 before spraying and applying the solution L to the substrate W by the coating apparatus having the above-described configuration is shown in FIGS. Will be described with reference to FIG.
[0043]
When air bubbles are removed from the supply pipe 21, the head 7, and the collection pipe 23, first, as shown in FIG. 14 is located below. Next, as shown in FIG. 5A, the upper and lower tables 54 are raised, and the nozzles 14 of the heads 7 are closed by the upper end surface of the pressing member 55.
[0044]
Each pressing member 55 is supported on the upper and lower tables 54 by a spring 57 so as to be elastically displaceable in the vertical direction. Therefore, even if there is some variation in the height dimension of the pressing member 55 and the height position of the lower surface of the head 7, the nozzle 14 of each head 7 can be reliably closed by each pressing member 55.
[0045]
When the nozzle 14 is closed by the pressing member 55, the supply on / off valve 25 and the recovery on / off valve 26 of each head 7 are opened, the communication valve 27 is closed, and the main recovery valve 28 is opened. Then, by closing the first open / close control valve 36 and opening the second and third open / close control valves 37 and 40 provided in the gas supply pipe 38, the solution L in the solution tank 31 is added by an inert gas. Press.
[0046]
As a result, the solution L in the solution tank 31 flows into the liquid chamber 12 of the head 7 through the supply pipe 21, fills the liquid chamber 12 and then flows into the collection pipe 23, and is collected from the collection pipe 23 to the storage tank 32. Therefore, the bubbles in the supply pipe 21, the liquid chamber 12 of the head 7, and the recovery pipe 23 can be removed together with the solution L. That is, air bubbles can be removed.
[0047]
Since the nozzle 14 of the head 7 is sealed by the pressing member 55 as shown in FIG. 5A when the bubbles in the supply pipe 21, the liquid chamber 12 of the head 7 and the recovery pipe 23 are removed, the supply The solution L supplied from the tube 21 to the liquid chamber 12 of the head 7 is prevented from flowing out from the nozzle 14 into the atmosphere.
[0048]
Therefore, the solution L does not flow out of the nozzle 14 when the above-mentioned air bubbles are removed, and does not become unusable due to contact with the atmosphere. That is, air bubbles can be removed from the supply pipe 21, the liquid chamber 12 of the head 7, and the recovery pipe 23 without wasting the solution L.
[0049]
By closing the nozzle 14 with the pressing member 55 and removing bubbles, the solution L supplied to the liquid chamber 12 of the head 7 can be surely flowed to the recovery tube 23 even if the resistance of the recovery tube 23 is large. it can. That is, even when the diameter of the recovery pipe 23 is reduced and the resistance increases, the solution L can be reliably recovered in the recovery pipe 23 without flowing out of the nozzle 14.
[0050]
Therefore, by reducing the diameter of the recovery tube 23, the amount of the solution L remaining in the recovery tube 23 after removing the bubbles can be reduced, so that waste of the solution L can be reduced.
[0051]
Next, air bubbles are removed from the nozzle 14 of the head 7. In order to remove bubbles from the nozzles 14, first, the supply opening / closing valve 25 of each head 7 is opened, and the recovery opening / closing valve 26 is closed. The pressing member 55 is raised as shown in FIG. 5A to close the nozzles 14 of the heads 7.
[0052]
In this state, an inert gas is supplied to the solution tank 31 to pressurize the internal solution L. Thereby, the solution L flows into the liquid chamber 12 of the head 7 through the supply pipe 21. The solution L that has flowed into the liquid chamber 12 cannot flow out of the liquid chamber 12 because the nozzle 14 and the recovery opening / closing valve 26 are closed. Therefore, the pressure of the solution L in the liquid chamber 12 increases.
[0053]
If the pressure of the solution L in the liquid chamber 12 is increased, the lowering of the upper and lower tables 54 shown in FIG. 5B and the raising shown in FIG. The nozzle 14 is opened and closed repeatedly.
[0054]
Accordingly, the solution L in the liquid chamber 12 rises to a predetermined pressure in the liquid chamber 12 and is then ejected from the nozzle 14. Therefore, even if the solution L is difficult to flow by simply flowing the solution L into the liquid chamber 12, the solution L can be surely flowed, so that all the nozzles formed on the head 7 are provided with the solution L. 14 can be sprayed uniformly. That is, by pulsating the pressure of the solution L in the liquid chamber 12, the solution L can be spread throughout the liquid chamber 12 and ejected from all the nozzles 14.
[0055]
Therefore, it is possible to reliably remove bubbles from all the nozzles 14 of the head 7 in a short time. For this reason, it is possible to prevent an excessive amount of the solution L from being ejected from the nozzle 14 at a location where the solution L easily flows, and thus it is possible to reduce the amount of the solution L that is ejected from the nozzle 14 and discarded.
[0056]
When the bubble removal from the nozzle 14 is completed in this way, the upper and lower tables 54 are raised to bring the wiping member 58 into contact with the lower surface of the head 7 as shown in FIG. In this state, the transfer table 3 is reciprocated and the solution L remaining on the lower surface of the head 7 is wiped off by the wiping member 58.
[0057]
Thereby, when the solution L is sprayed and applied to the substrate W after removing bubbles, the adverse effect such as obstruction of the spraying direction of the solution L from the nozzle 14 by the solution remaining on the lower surface of the head 7 is removed. Can do.
[0058]
When removing air bubbles from the nozzle 14 of the head 7, the upper and lower tables 54 are moved up and down and the nozzle 14 is repeatedly opened and closed by the presser member 55. However, by using the wiping member 58 as a sealing member, 14 may be repeatedly opened and closed.
[0059]
That is, the transport table 3 is reciprocated in a state where the upper end of the wiping member 58 is in contact with the lower surface of the head 7 as shown in FIG. Accordingly, the upper end portion of the wiping member 58 opens and closes the nozzle 14, so that the pressure of the solution L in the liquid chamber 12 can be pulsated.
[0060]
That is, when the wiping member 58 closes the nozzle 14, the pressure of the solution L in the liquid chamber 12 rises and the solution L spreads throughout the liquid chamber 12, and when opened, the solution L spreads throughout the liquid chamber 12. Ejects from all nozzles 14 of the head 7.
[0061]
As described above, the sealing member that repeatedly opens and closes the nozzle 14 and applies pressure pulsation to the solution L may be either the holding member 55 or the wiping member 58. In short, the pressure pulsation is applied to the solution L. It only needs to be given.
[0062]
When air bubbles are removed from the nozzle 14, a pulsation may be applied to the pressure of the solution L using the supply opening / closing valve 25 or the recovery opening / closing valve 26 instead of the sealing member. That is, as a first method for that purpose, when supplying the solution L to the liquid chamber 12 of the head, the supply on-off valve 25 is repeatedly opened and closed with the recovery on-off valve 26 closed. As a result, the pressure of the solution L supplied from the supply pipe 21 to the liquid chamber 12 pulsates, so that the solution L supplied to the liquid chamber 12 is easily dispersed throughout the liquid chamber 12. Therefore, the solution L can be reliably sprayed from all the nozzles 14 formed on the head 7 in a short time.
[0063]
As a second method, the supply opening / closing valve 25 is normally opened to supply the solution L to the liquid chamber 12 of the head 7 and the collection opening / closing valve 26 is repeatedly opened and closed. As a result, the solution L supplied to the liquid chamber 12 flows into the recovery pipe 23 in response to the opening / closing of the recovery on-off valve 26, and the pressure of the solution in the liquid chamber 12 pulsates by the flow.
[0064]
If the pressure of the solution in the liquid chamber 12 pulsates, the solution L can be reliably jetted from all the nozzles 14 communicating with the liquid chamber 12 in a short time as in the above embodiments.
[0065]
【The invention's effect】
As described above, according to the present invention, it is possible to surely perform the bubble removal of the coating apparatus that sprays and applies the solution to the substrate without causing waste in the solution. Further, the diameter of the recovery tube can be reduced, and the amount of the solution remaining in the recovery tube after removing bubbles can be reduced, so that waste of the solution can be reduced.
[Brief description of the drawings]
FIG. 1 is a front view showing a schematic configuration of a coating apparatus showing an embodiment of the present invention.
FIG. 2 is a side view of the coating apparatus.
FIG. 3 is a cross-sectional view of the head.
FIG. 4 is a bottom view of the head.
FIGS. 5A to 5C are explanatory views of the opening / closing operation of the nozzle by the pressing member when the supply pipe, the head, and the recovery pipe are degassed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 3 ... Conveyance table, 7 ... Head, 14 ... Nozzle, 21 ... Supply pipe, 23 ... Collection pipe, 25 ... Supply on-off valve, 26 ... Collection on-off valve, 31 ... Solution tank, 54 ... Upper and lower table, 55 ... Holding member ( Sealing member), 58 .. Wiping member (sealing member).

Claims (4)

In a coating apparatus that sprays and applies a solution to a substrate,
A head having a nozzle for ejecting the solution by an inkjet method;
A source of the solution;
A supply pipe for connecting the supply source and the head and supplying the solution of the supply source to the head;
When the nozzle of the head is pressed against the surface on which the nozzle is formed, the nozzle can be closed, and when the solution supplied under pressure to the head from the supply source through the supply pipe is ejected from the nozzle And a sealing member that repeatedly opens and closes the nozzle so as to pulsate the pressure of the solution supplied from the supply source and flowing into the head. The substrate is placed on a transfer table that is driven to reciprocate under the head, and an upper and lower table is provided on one end surface positioned in the drive direction of the transfer table so as to be movable up and down. The sealing member is the upper and lower table. coating apparatus of the solution of claim 1 Symbol mounting, characterized in that provided in the.   3. The wiping member according to claim 1, wherein the sealing member is a wiping member that opens and closes the nozzle by reciprocating along the lower surface of the head in a state where the upper end is in contact with the lower surface of the head. Solution applicator. In a coating apparatus having a head having a nozzle for ejecting a solution by an ink jet method and a supply pipe for supplying the solution to the head, the bubble removing method for removing bubbles from the nozzle prior to use,
The pressure of the solution that is pressurized and supplied from the supply source and flows through the head when the air bubbles are discharged from the nozzle of the head by discharging the solution that is pressurized and supplied to the head through the supply pipe. Of the coating apparatus, wherein the sealing member capable of closing the nozzle by pressing the nozzle against the surface on which the nozzle of the head is formed is moved up and down to repeatedly open and close the nozzle, thereby causing pulsation. How to remove air bubbles.

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