JP2015178066A - Coating applicator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating applicator and a coating method capable of preventing the occurrence of liquid dripping from a discharge port after the completion of coating.SOLUTION: A coating applicator 1 comprises: a mouthpiece 2 having a discharge port 11 for discharging a coating liquid; liquid supply means 3 for supplying the coating liquid to the mouthpiece 2; and a flexible liquid feed pipe 4 which is a path of the coating liquid from the liquid supply means 3 to the mouthpiece 2. The coating applicator 1 applies the coating liquid to a base plate W by discharging the coating liquid supplied from the liquid supply means 3 from the discharge port 11 of the mouthpiece 2. In a pressure adjustment portion 6 that is a part or whole of the liquid feed pipe 4, a closed space 24 is formed at the outer peripheral part of the pressure adjustment portion 6, and pipe pressure adjustment means 5 for adjusting the closed space 24 is provided.

Description

  The present invention relates to a coating apparatus and a coating method for coating a coating liquid on a substrate such as glass and forming a coating film.

  A flat panel display such as a liquid crystal display or a plasma display uses a substrate coated with a resist solution (referred to as a coated substrate). The coated substrate is formed by a coating apparatus that uniformly coats a coating solution such as a resist solution or a chemical solution on the substrate.

  For example, as shown in Patent Document 1, this coating apparatus discharges a paste-like coating liquid from a slit-shaped discharge port of a base, and applies the coating liquid to a substrate that moves relative to the base immediately below the base. ing.

  As a method of discharging the coating liquid from the discharge port, a method of pushing the coating liquid from the discharge port by pumping the coating liquid from a liquid supply means such as a pump storing the coating liquid to the base through a pipe is used. .

JP 2005-244155 A

  However, in such a coating apparatus, dripping occurs from the discharge port at the end of coating, and the dripping coating liquid may adhere to the substrate and deteriorate the quality of the substrate. Specifically, as shown in FIG. 6, while the coating liquid is applied to the substrate, the coating liquid is pumped at a constant flow rate from a liquid supply means (not shown) included in the coating apparatus 90. Due to the internal pressure, the diameter of the liquid feeding pipe 93 is increased as indicated by a two-dot chain line in the figure. On the other hand, when the application is completed and the liquid supply from the liquid supply means is stopped, the liquid supply pipe 93 behaves to return to the original diameter as indicated by an arrow in the figure, and the volume decreases. . Thus, there is a possibility that the coating liquid corresponding to the change in the volume of the liquid feeding pipe 93 may be discharged as a dripping 94 from the discharge port 92 of the base 91.

  As a method for preventing the dripping 94 from being generated from the discharge port 92 as described above, for example, there is a method in which the liquid supply means absorbs the coating liquid corresponding to the change in the volume of the liquid supply pipe 93 by performing a suction operation. When the length of the liquid pipe 93 is long, it takes time until the effect of the suction operation is transmitted to the discharge port 92, and as a result, the liquid drip 94 has occurred first. In addition, this phenomenon was more noticeable as the viscosity of the coating solution was higher.

  The present invention has been considered in view of the above-described problems, and provides a coating apparatus and a coating method capable of preventing dripping from a discharge port at the end of coating.

  In order to solve the above problems, a coating apparatus of the present invention includes a base having a discharge port for discharging a coating liquid, a liquid supply means for supplying the coating liquid to the base, and a coating liquid from the liquid supply means to the base. An applicator for applying the coating liquid to the substrate by discharging the coating liquid supplied from the liquid supply means from the discharge port of the base. And a pressure adjusting part which is a part or the whole of the liquid feeding pipe is provided with a pipe pressure adjusting means for forming a closed space on the outer periphery of the pressure adjusting part and adjusting the pressure of the closed space. It is characterized by that.

  According to this coating apparatus, the pressure adjusting part which is a part or the whole of the liquid feeding pipe has a closed space on the outer periphery of the pressure adjusting part, and the pipe pressure adjusting means for adjusting the pressure of the closed space is provided. By being provided, it is possible to remove the residual pressure of the liquid feeding pipe immediately after the application is completed, and to prevent dripping from the discharge port. Specifically, while applying the liquid, the pressure of the closed space is increased by the pipe pressure adjusting means to pressurize the liquid supply pipe, and immediately after the application is finished, the pressurization of the closed space is released. The piping expands and the residual pressure in the liquid feeding piping is removed.

  The pipe pressure adjusting means may be connected to the base.

  By doing so, since the residual pressure removal work is performed in the immediate vicinity of the die, the effect of the residual pressure removal can be reflected in the behavior of the coating liquid at the discharge port with good responsiveness.

  In order to solve the above problems, the coating method of the present invention includes a base having a discharge port for discharging a coating liquid, a liquid supply means for supplying a coating liquid to the base, and a liquid supply means to the base. A coating liquid path, and a liquid feeding pipe having flexibility, and a coating method for coating the coating liquid on a substrate by a coating apparatus, wherein a pressure adjusting portion which is a part or the whole of the liquid feeding pipe A pressurizing step of pressurizing from the outer periphery of the pressure adjusting portion; a discharge step of supplying a coating liquid from the liquid supply means to the base; and discharging from the discharge port of the base; and a step of supplying from the liquid supply means to the base It is characterized by having a supply stop step for stopping the supply of the coating liquid and a pressure release step for releasing the pressurization to the pressure adjusting portion.

  According to this coating method, by having a pressurization step and a pressurization release step, the liquid feed pipe is expanded immediately after the end of the coating to remove the residual pressure in the liquid feed pipe, and from the discharge port Dripping can be prevented.

  According to the coating apparatus and the coating method of the present invention, it is possible to prevent dripping from the discharge port after the coating is completed.

It is the schematic which shows the structure of the coating device in one Embodiment of this invention. It is the schematic which shows the state of the coating device at the time of a coating standby. It is the schematic which shows the state of the coating device at the time of application | coating. It is the schematic which shows the state of the coating device at the time of completion | finish of application | coating. It is an operation | movement flow of the coating device concerning this invention. It is the schematic which shows the conventional coating device.

  Embodiments according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing a coating apparatus according to an embodiment of the present invention.

  The coating apparatus 1 has a base 2 and a liquid supply means 3. The base 2 and the liquid supply means 3 are connected by a liquid supply pipe 4, and the coating liquid L is supplied from the liquid supply means 3 to the base 2 via the liquid supply pipe 4 and is provided in one direction provided in the base 2. From the long discharge port 11. In this way, under the state in which the coating liquid L is being discharged from the discharge port 11, the substrate W is transported by a transport device (not shown) directly below the discharge port 11, so that the coating film of the coating liquid L is formed on the substrate W. It is formed.

  Further, the coating apparatus 1 further has a pipe pressure adjusting means 5 for adjusting the pressure applied from the outer periphery to the pressure adjusting portion 6 corresponding to a part or all of the liquid feeding pipe 4.

  In the following description, the longitudinal direction of the discharge port 11 is the Y-axis direction, and the direction orthogonal to the Y-axis direction on the horizontal plane is the direction orthogonal to both the X-axis direction, the X-axis direction, and the Y-axis direction, that is, the vertical direction. Is called the Z-axis direction.

  The base 2 is a metal block whose longitudinal direction is the Y-axis direction, and has a slit whose longitudinal direction is the Y-axis direction. The discharge port 11 that is the opening end of this slit is the base 2. It is provided on the lower surface of. Further, the slit communicates with the liquid feeding pipe 4, and the coating liquid L that has flowed from the liquid feeding pipe 4 is discharged from the discharge port 11 in a band shape through the slit.

  Thus, while the coating liquid L is being discharged from the discharge port 11, the substrate W is transferred in a direction (X-axis direction) perpendicular to the longitudinal direction of the discharge port 11 by a transfer device (not shown), The coating liquid L is applied to the substrate W.

  Here, the interval between the slits (distance in the X-axis direction) is uniform over the longitudinal direction (Y-axis direction) of the slit, and the coating liquid L is ejected from the ejection port 11 of the base 2 at a uniform flow rate in the longitudinal direction. Is done. Accordingly, the substrate W is transported at a constant transport speed, and the coating liquid L is applied from the base 2 thereon, whereby a coating film having a uniform film thickness is formed over the entire surface of the substrate W. In the present embodiment, the viscosity of the coating liquid L is 3 cP to 20,000 cP.

  The liquid supply means 3 is means for supplying the coating liquid L to the base 2 by pumping the coating liquid L stored in the base 2 to the base 2, and is a piston pump in this embodiment. The liquid supply means 3 is connected to the base 2 via the liquid supply pipe 4 as described above. The liquid supply pipe 4 serves as a path for the coating liquid L, and the coating liquid L is sent from the liquid supply means 3 to the base 2. It is done.

  Here, the liquid supply pipe 4 is a flexible tube made of, for example, PTFE (polytetrafluoroethylene).

  Further, an opening / closing valve 13 is provided in the middle of the liquid feeding pipe 4, and the coating liquid L in the liquid supply means 3 can be fed to the base 2 when the opening / closing valve 13 is in an open state. It is.

  In FIG. 1 and subsequent figures, the open / close valve in the open state is not painted, but the open / close valve in the closed state is filled.

  On the other hand, the liquid supply means 3 is also connected to the tank 12 via a pipe different from the liquid feed pipe 4. The liquid supply means 3 can store an amount of the coating liquid L that can be applied to the substrate W several times, whereas the tank 12 has a much larger amount of coating liquid than the storage amount of the liquid supply means 3. L can be stored. Therefore, every time coating of the coating liquid L onto the substrate W is completed a predetermined number of times, an operation of replenishing the coating liquid L from the tank 12 to the liquid supply means 3 is performed.

  Here, an opening / closing valve 14 is also provided between the liquid supply means 3 and the tank 12, and when applying the coating liquid L to the substrate W, the opening / closing valve 13 is opened and the opening / closing valve 14 is closed. By separating the tank 12 from the piping path, and when replenishing the coating liquid L from the tank 12 to the liquid supply means 3, the piping path is established by closing the opening / closing valve 13 and opening the opening / closing valve 14. The base 2 is separated from the base.

  In this embodiment, the pipe pressure adjusting means 5 has a main body 21, a gas supply source 22, and a vacuum source 23.

  In this embodiment, the main body 21 has a hollow cylindrical shape whose central axis is the direction in which the liquid supply pipe 4 extends (X-axis direction). This is the same as the dimension in the X-axis direction of the pressure adjusting portion 6 that is part or all of the liquid piping 4.

  The diameter of the space inside the main body 21 is larger than the outer diameter of the liquid feeding pipe 4, and through holes having substantially the same diameter as the outer diameter of the liquid feeding pipe 4 are provided on both end surfaces of the main body 21. It has been. The liquid supply pipe 4 passes through these through holes, and a portion corresponding to the pressure adjusting portion 6 of the liquid supply pipe 4 is disposed inside the main body portion 21, and both end faces of the main body portion 21 and the liquid supply pipe 4 are in these through holes. A closed space 24 is formed on the outer periphery of the pressure adjusting portion 6 by being hermetically sealed with, for example, a rubber ring.

  Moreover, the main-body part 21 has a material harder than the liquid feeding piping 4, for example, is comprised with metals, such as stainless steel.

  The gas supply source 22 is, for example, a pump, a blower or the like, and is connected to the main body 21 via a pipe, and feeds a gas such as dry air or nitrogen into the internal space (closed space 24) of the main body 21. An open / close valve 25 is provided in the pipe between the gas supply source 22 and the main body 21. When the gas supply source 22 supplies gas to the closed space 24, the pressure in the closed space 24 increases and the pressure adjusting portion 6 is compressed, so that the diameter of the pressure adjusting portion 6 is reduced.

  The vacuum source 23 is, for example, a pump or a blower, and is connected to the main body portion 21 via a pipe, and sucks the gas in the internal space (closed space 24) of the main body portion 21. An opening / closing valve 26 is provided in the pipe between the vacuum source 23 and the main body 21. When the vacuum source 23 sucks the gas in the closed space 24, the pressure in the closed space 24 is lowered, so that the diameter of the pressure adjusting portion 6 is increased.

  Next, the dripping prevention operation by the coating apparatus 1 of the present invention will be described with reference to FIGS.

  First, the state of the coating apparatus 1 at the time of coating standby is shown in FIG. Note that the coating standby time is a standby time before the application of the coating liquid L to the substrate W is started.

  At the time of application standby, the on-off valve 13 is closed and the flow of the application liquid L does not occur, but the liquid supply pipe 4 and the base 2 are held in a state where the application liquid L is filled. If the coating liquid L is fed to the inside of the liquid feeding pipe 4 and the base 2 for the first time immediately before the start of coating, bubbles existing inside the liquid feeding pipe 4 and the base 2 are dissolved in the fed coating liquid L, There is a possibility that the film of the coating liquid L formed on the substrate W may be adversely affected. In order to prevent this, a sufficient amount of the coating liquid L is poured into the liquid feeding pipe 4 and the base 2 before coating, so that bubbles do not dissolve in the coating liquid L filled in the liquid feeding pipe 4 and the base 2. Is formed at the time of application standby.

  Here, at the time of waiting for application, the inner diameter of the liquid feeding pipe 4 is d0 in both the portion corresponding to the pressure adjusting portion 6 and the portion other than the pressure adjusting portion 6. At the time of this application standby, both the opening / closing valve 25 and the opening / closing valve 26 are closed, and no change in atmospheric pressure occurs in the closed space 24.

  Next, the state of the coating apparatus 1 at the time of application | coating is shown in FIG.

  Prior to the application of the coating liquid L to the substrate W, first, the open / close valve 25 is opened, a state in which the air pressure in the closed space 24 is high is formed, and the inner diameter of the pressure adjusting portion 6 is reduced. Here, the open / close valve 25 may be closed when the pressure in the closed space 24 reaches a predetermined value.

  After the inner diameter of the pressure adjusting portion 6 is reduced in this way, the open / close valve 13 is opened, and the liquid supply means 3 starts feeding the coating liquid L, and the coating liquid L is applied to the substrate W. Is called. Thus, when the coating liquid L is fed, the internal pressure of the liquid feeding pipe 4 is increased by the flow of the coating liquid L, and the inner diameter of the liquid feeding pipe 4 is pushed from the inside. For this reason, the inner diameter of the liquid supply pipe 4 at a portion other than the pressure adjusting portion 6 is d2 which is larger than d0, and the volume of the pipe is larger than that at the time of application standby.

  On the other hand, in the pressure adjusting portion 6, the pipe is compressed by the closed space 24 as described above, and the inner diameter at the time of liquid feeding is d1, which is smaller than d0. ing. Here, it is preferable that the decrease in the volume in the pressure adjusting portion 6 and the increase in the volume in the liquid feeding pipe 4 other than the pressure adjusting portion 6 are equal.

  Next, the state of the coating apparatus 1 at the end of coating is shown in FIG.

  When the application of the coating liquid L to the substrate W is completed, the opening / closing valve 13 is closed, and the feeding of the coating liquid L from the liquid supply means 3 is stopped. As a result, the internal pressure of the liquid supply pipe 4 becomes equivalent to that during the coating standby, and therefore, as shown by the arrows in the figure, the inner diameter of the liquid supply pipe 4 at a portion other than the pressure adjusting portion 6 returns from d2 to d0. . At this time, since the volume of the pipe is reduced, the coating liquid L is pushed out from this portion toward the discharge port 11 of the base 2. If left untreated, there is a possibility that dripping will occur at the discharge port 11.

  Therefore, when the opening / closing valve 26 of the pipe pressure adjusting means 5 is opened and the closed space 24 is decompressed, the inner diameter of the pressure adjusting portion 6 is instantaneously larger than d1. As a result, the volume of the pressure adjusting portion 6 increases, and therefore, the coating liquid L pushed out from the liquid feeding pipe 4 in a portion other than the pressure adjusting portion 6 can be absorbed and dripping can be prevented from occurring at the discharge port 11. . In particular, when using a high-viscosity coating liquid L having a viscosity of 1,000 cP or more, there is a high possibility of dripping at the discharge port 11 if left without taking measures against dripping. The effect of adjusting the pressure applied to the pressure adjusting portion 6 is great.

  Here, as described above, the decrease in the volume at the pressure adjusting portion 6 at the time of application and the increase in the volume in the liquid feeding pipe 4 in the portion other than the pressure adjusting portion 6 are equivalent, so that the discharge port is opened from the opening / closing valve 13. When the amount of the coating liquid L up to 11 is greater at the end of coating than at the time of coating standby, it prevents the liquid from dripping from the discharge port 11, and conversely, the coating from the on-off valve 13 to the discharge port 11 is prevented. When the amount of the liquid L is less at the end of the application than at the time of application standby, it is possible to prevent the application liquid L from being drawn into the slit from the discharge port 11 and causing air entrainment in the vicinity of the discharge port 11.

  In order to further prevent the occurrence of dripping, as shown in FIG. 4, the closed space 24 may be set to atmospheric pressure or less so that the inner diameter of the pressure adjusting portion 6 is once expanded to d3 larger than d0. . In this case, the closed space 24 may be returned to the atmospheric pressure by an atmospheric release mechanism (not shown) after the closed space 24 is reduced to the atmospheric pressure or lower and the dripping prevention work is completed.

  Further, the pipe pressure adjusting means 5 is preferably arranged as close to the base 2 as possible in order to quickly reflect the effect of the pressure adjustment on the discharge port 11 of the base 2. Therefore, it is more preferable that the feed pipe pressure adjusting means 5 is connected to the base 2 so that the liquid feed pipe 4 that is not the pressure adjusting portion 6 does not exist between the pipe pressure adjusting means 5 and the base 2.

  Next, an operation flow of the coating apparatus according to the present invention is shown in FIG. Here, as a condition before the coating apparatus 1 starts coating on the substrate W (at the time of coating standby), the coating liquid L is filled in the liquid feeding pipe 4 and the base 2 including the pressure adjusting portion 6. It is assumed that the on-off valve 13, the on-off valve 14, the on-off valve 25, and the on-off valve 26 are in a closed state. In addition, the inner diameter of the liquid feeding pipe 4 at this time is assumed to be d0 (see FIG. 2). Further, it is assumed that the gas supply source 22 and the vacuum source 23 are always operating.

  First, the open / close valve 25 is opened (step S1). Thereby, since gas is sent from the gas supply source 22 to the closed space 24 and the atmospheric pressure in the closed space 24 is increased, the liquid supply pipe 4 corresponding to the pressure adjusting portion 6 is pressurized from the outer periphery, and the inner diameter is reduced. In this description, the step of pressurizing the pressure adjusting portion 6 from the outer periphery is referred to as a pressurizing step. In this embodiment, the opening / closing valve 25 is always open while application to the substrate W is performed, but may be closed when the pressure of the closed space 24 reaches a predetermined pressure. .

  Next, the open / close valve 13 is opened, and the supply of the coating liquid L from the liquid supply means 3 to the liquid supply pipe 4 is started (step S2). As a result, the coating liquid L is discharged from the discharge port 11 of the base 2, and the coating liquid L is applied to the substrate W transported below the discharge port 11. The step of supplying the coating liquid L from the liquid supply means 3 to the base 2 and discharging the coating liquid L from the discharge port 11 is called a discharge step in this description. Note that either the timing at which the on-off valve 13 is opened or the timing at which the liquid supply means 3 supplies the coating liquid L may be first. In this discharge step, the inner diameter of the liquid feeding pipe 4 is d1 smaller than the inner diameter d0 at the time of liquid feeding standby at the portion of the pressure regulating portion 6, and d2 larger than d0 at the portion other than the pressure regulating portion 6 ( (See FIG. 3).

  Next, the application of the coating liquid L to the substrate W is completed, the open / close valve 13 is closed, and the supply of the coating liquid L from the liquid supply means 3 to the liquid feeding pipe 4 is stopped (step S3). . The step of stopping the supply of the coating liquid L in this way is referred to as a supply stop step in this description. Note that either the timing at which the on-off valve 13 is closed or the timing at which the liquid supply means 3 stops supplying the coating liquid L may be first. When the supply of the coating liquid L is stopped in this way, the internal pressure in the liquid feeding pipe 4 decreases, and the inner diameter returns to the inner diameter d0 at the time of waiting for application at a portion other than the pressure adjusting portion 6 (see FIG. 4). ).

  Immediately after step S3, the opening / closing valve 25 is closed, and instead, the opening / closing valve 26 is opened (step S4). As a result, the pressurization of the closed space 24 is stopped and, conversely, the gas is sucked by the vacuum source 23 and the atmospheric pressure is reduced (the pressurization is released). The pressure decreases and the inner diameter increases. In this description, the step of releasing the pressurization to the pressure adjusting portion 6 is called a pressurization releasing step. In the present embodiment, the pressure in the closed space 24 is once lower than the atmospheric pressure by the vacuum source 23, and the inner diameter of the portion of the pressure adjusting portion 6 becomes d3 which is larger than the inner diameter d0 in the coating standby (see FIG. 4). If the opening / closing valve 25 is closed when the pressure in the closed space 24 reaches a predetermined pressure in the previous step, the operation of closing the opening / closing valve 25 in this step is omitted.

  Finally, the opening / closing valve 26 is closed (step S5), and a series of coating operations is completed. Here, when the atmospheric pressure of the closed space 24 is different from the atmospheric pressure, after the opening / closing valve 26 is closed, the closed space 24 is opened to the atmosphere by an air release valve (not shown) or the like.

  By the above coating apparatus and coating method, it is possible to prevent dripping from the discharge port after the coating is completed.

  In this description, the piping pressure adjusting means 5 is provided with the vacuum source 23, but instead of the vacuum source 23, a mechanism for releasing the atmosphere is provided, and the atmosphere of the closed space 24 is released to the atmosphere when the application is completed. You may make it the diameter of the pressure regulation site | part 6 spread.

  Further, in this description, the dripping from the discharge port 11 is prevented only by the pressure adjustment by the pipe pressure adjusting means 5, but the suction operation by the liquid supply means which is a conventional dripping prevention means may be performed together. Absent.

  In this description, only one pipe pressure adjusting means 5 is provided. However, a plurality of pipe pressure adjusting means 5 are provided on the liquid supply pipe 4, and the liquid supply pipes are sequentially arranged from the pipe pressure adjusting means 5 on one side. The pressure may be adjusted to 4.

DESCRIPTION OF SYMBOLS 1 Application | coating apparatus 2 Base 3 Liquid supply means 4 Liquid supply piping 5 Piping pressure adjustment means 6 Pressure adjustment part 11 Discharge port 12 Tank 13 Opening and closing valve 14 Opening and closing valve 21 Main body part 22 Gas supply source 23 Vacuum source 24 Closed space 25 Opening and closing valve 26 Opening and closing valve 90 Coating device 91 Base 92 Discharge port 93 Liquid supply piping 94 Liquid dripping L Coating liquid W Substrate

Claims (3)

A base having a discharge port for discharging the coating liquid;
A liquid supply means for supplying a coating liquid to the die;
It is a path of the coating liquid from the liquid supply means to the base, and a flexible liquid feeding pipe;
A coating apparatus that applies the coating liquid to the substrate by discharging the coating liquid supplied from the liquid supply means from the discharge port of the base,
The pressure adjusting part which is a part or the whole of the liquid supply pipe is provided with a pipe pressure adjusting means for forming a closed space on the outer periphery of the pressure adjusting part and adjusting the pressure of the closed space. A characteristic coating apparatus.   The coating apparatus according to claim 1, wherein the pipe pressure adjusting unit is connected to the base. A base having a discharge port for discharging the coating liquid;
A liquid supply means for supplying a coating liquid to the die;
It is a path of the coating liquid from the liquid supply means to the base, and a flexible liquid feeding pipe;
Is a coating method in which a coating solution is applied to a substrate by a coating apparatus equipped with
A pressurizing step of pressurizing a part or all of the liquid feeding pipe from the outer periphery of the pressure regulating part;
A discharge step of supplying a coating liquid from the liquid supply means to the base, and discharging from the discharge port of the base;
A supply stop step of stopping the supply of the coating liquid from the liquid supply means to the die;
A pressure release step for releasing the pressure applied to the pressure adjusting portion;
A coating method characterized by comprising:

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