JP2018043219A - Nozzle cleaning method, and coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove particles adhered to a nozzle detached from a coating device.SOLUTION: A nozzle cleaning method includes: a process of circulating a cleaning liquid with lower viscosity than a coating liquid in a first circulation system in which the cleaning liquid goes out of a drain port and returns to a supply port in a sealed state of a discharge port of a nozzle attached on an attachment part of a coating device which coats an object with the coating liquid discharged from the discharge port of the nozzle by supplying the coating liquid to an internal space from the supply port of the nozzle, which has the supply port, the discharge port, and the drain port communicating with the internal space, is detachable from the attachment part, and is attached on the attachment part; a process of detaching the nozzle cleaned by circulation of the cleaning liquid in the first circulation system from the attachment part, and attaching the nozzle on the attachment part after a predetermined work is executed on the nozzle; and a process of circulating the cleaning liquid in a second circulation system in which the cleaning liquid goes out of the drain port and returns to the supply port in the sealed state of the discharge port of the nozzle attached on the attachment part after the predetermined work is executed, and has a filter between the drain port and the supply port.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a glass substrate for a liquid crystal display device, a semiconductor wafer, a glass substrate for a PDP, a glass substrate for a photomask, a glass substrate for supporting a polyimide precursor thin film, a substrate for a color filter, a substrate for a recording disk, and a substrate for a solar cell. The present invention relates to a technique for cleaning the inside of a nozzle of a coating apparatus that discharges a coating liquid from a nozzle discharge port to a precision electronic device substrate (hereinafter simply referred to as “substrate”) such as an electronic paper substrate.

  2. Description of the Related Art Conventionally, a coating apparatus that applies a coating liquid to an object by discharging the coating liquid from a nozzle is known. This nozzle has a cavity formed therein, and a supply port and a discharge port respectively communicating with the cavity. And a coating liquid is apply | coated to a target object by the coating liquid supplied in the cavity from the supply port being discharged from a discharge outlet. Patent Document 1 describes a technique for cleaning such a nozzle. In this cleaning technique, with the nozzle discharge port sealed, the cleaning liquid supplied to the cavity from the supply port (chemical solution introduction unit) is discharged from the discharge ports (chemical solution outlet unit) opened on both sides of the nozzle. Clean the cavity inside the nozzle.

Japanese Patent No. 525849

  By the way, in order to perform a predetermined operation (manual operation) such as disassembly cleaning of the nozzle or adjustment of the component parts of the nozzle, an operator may appropriately remove the nozzle from the coating apparatus. At this time, by removing the nozzle after cleaning the nozzle, the operator can perform a predetermined operation on a relatively clean nozzle with a small amount of coating liquid attached. However, during execution of such a predetermined operation, particles can adhere to the inner wall of the internal space (cavity) of the nozzle. For this reason, when the application is performed after the nozzle is attached to the application device, the particles are discharged from the discharge port together with the coating liquid, and the target object may be contaminated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of removing particles adhering to a nozzle removed from a coating apparatus for a predetermined operation.

  In the nozzle cleaning method according to the present invention, the nozzle having the supply port, the discharge port, and the discharge port communicating with the internal space is detachable from the mounting location, and the coating liquid is supplied from the nozzle supply port attached to the mounting location to the internal space. In the state where the nozzle discharge port attached to the mounting position of the coating apparatus that applies the coating liquid discharged from the nozzle discharge port to the target is sealed, the nozzle exits from the discharge port and returns to the supply port. After the step of circulating a cleaning liquid having a viscosity lower than that of the coating liquid in the first circulation system, the nozzle cleaned by the circulation of the cleaning liquid in the first circulation system is removed from the mounting location, and a predetermined operation is performed on the nozzle, The process of attaching the nozzle to the installation location and the discharge port of the nozzle attached to the installation location is sealed after the predetermined operation is performed, and then returns to the supply port and is supplied from the discharge port. And a step of circulating the washing liquid in the second circulation system with filter until.

  In the nozzle cleaning method configured as described above, the cleaning liquid is circulated in the first circulation system that exits from the discharge port and returns to the supply port in a state where the discharge port of the nozzle is sealed, and then the nozzle is mounted on the coating device. Removed from. As a result, the operator can perform a predetermined operation on a relatively clean nozzle with a small amount of coating liquid attached. In addition, when the nozzle on which the predetermined operation has been performed is attached to the mounting position of the coating apparatus, the cleaning liquid is circulated in the second circulation system that exits from the discharge port and returns to the supply port with the nozzle discharge port sealed. Therefore, particles can be washed away from the internal space of the nozzle by the cleaning liquid circulating in the second circulation system. In addition, since the second circulation system has a filter between the discharge port and the supply port, the washed-out particles can be collected by the filter and the particles can be prevented from returning to the internal space of the nozzle. In this way, it is possible to remove particles adhering to the nozzle removed from the coating apparatus for a predetermined operation.

  Incidentally, in the present invention, in cleaning the nozzle before removing the nozzle, the cleaning liquid is circulated in the first circulation system having no filter, whereas in the cleaning of the nozzle after mounting the nozzle, the filter is provided. The cleaning liquid is circulated in the second circulation system. One reason for using different filters in this way is as follows. That is, the cleaning in the first circulation system is performed mainly to wash away the components of the coating liquid that adheres to the inner wall of the internal space of the nozzle. Moreover, since the cleaning execution timing in the first circulation system is before the execution of the predetermined work by the operator, no particles are present in the first circulation system, and no filter is necessary in the first place. On the other hand, the cleaning in the second circulation system is executed mainly to remove particles adhering to the inner wall or the like of the internal space of the nozzle accompanying the removal of the nozzle. When such particles return to the internal space of the nozzle as the cleaning liquid circulates, the subsequent application is greatly affected. Therefore, in the cleaning in the first circulation system, the consumption of the filter is suppressed by not using the filter, and in the cleaning in the second circulation system, particles are collected by using the filter.

  Further, in the present invention, the nozzle is cleaned by circulating the cleaning liquid while sealing the nozzle outlet, in other words, the cleaning liquid is circulated and used for nozzle cleaning. Therefore, consumption of the cleaning liquid can be suppressed.

  Therefore, the nozzle cleaning method may be configured so that the cleaning liquid circulated in the first circulation system is circulated in the second circulation system. Thus, by using the cleaning liquid in common for the cleaning in the first circulation system and the cleaning in the second circulation system, consumption of the cleaning liquid can be more effectively suppressed.

  Further, the nozzle cleaning method may be configured to further include a step of introducing a gas into the first circulation system after the cleaning liquid is circulated in the first circulation system and before the nozzle is removed from the mounting position. good. In such a configuration, the nozzle can be removed after the cleaning liquid is pushed out by the gas introduced into the first circulation system. As a result, the operator can perform a predetermined operation on the dried nozzle.

  Further, the nozzle cleaning method may be configured to further include a step of introducing a gas into the second circulation system after the cleaning liquid is circulated in the second circulation system. In such a configuration, the cleaning liquid in the internal space of the nozzle can be pushed out by the gas introduced into the second circulation system. As a result, it is possible to suppress the cleaning liquid remaining in the internal space of the nozzle from affecting the application of the coating liquid to be executed later.

  Further, the nozzle cleaning method may be configured so that the coating liquid contains a polyimide precursor and a solvent, and the cleaning liquid is a solvent. That is, since the coating liquid containing a polyimide precursor has a high viscosity, it easily adheres to the inner wall of the internal space of the nozzle. Therefore, cleaning as described in Patent Document 1 is not sufficient, and it is highly necessary to perform manual cleaning, and problems such as particle adhesion are likely to occur. Therefore, as described above, it is particularly preferable to remove particles from the internal space of the nozzle by circulating the solvent (cleaning liquid) in the second circulation system having the filter after the nozzle is attached.

  A first aspect of a coating apparatus according to the present invention includes a supply port that communicates with an internal space, a slit-shaped discharge port, and a discharge port, and a nozzle that discharges the coating liquid supplied from the supply port to the internal space through the discharge port. A nozzle support part that detachably supports the nozzle at the mounting location, a pipe that constitutes a circulation path that returns from the discharge port to the supply port, and a cleaning liquid that is provided in the pipe and has a lower viscosity than the coating liquid A cleaning liquid circulating means having a liquid feeding section to be circulated, a filter removable from the pipe, and a sealing means capable of sealing the discharge port of the nozzle. The coating liquid is applied to the object by discharging the coating liquid from the discharge port without stopping, and the cleaning liquid circulating means is sealed by the sealing means and the filter is removed from the pipe. In the state, the cleaning liquid is circulated in the circulation path. And operation to the ring, the discharge port is an operation and circulating the washing liquid in the circulation path in the state in which the filter is attached to the pipe with sealed selectively executable by the sealing means.

  The coating apparatus configured in this manner applies the coating liquid to the object by discharging the coating liquid from the nozzle mounted at the attachment / detachment position of the nozzle support. That is, the nozzle has a supply port communicating with the internal space and a slit-shaped discharge port, and discharges the coating liquid supplied from the supply port to the internal space from the discharge port. Further, the nozzle has a discharge port communicating with its internal space, and the cleaning liquid circulating means cleans the nozzle by circulating the cleaning liquid through the supply port and the discharge port of the nozzle. The cleaning liquid circulation means has a pipe that constitutes a circulation path that exits from the discharge port and returns to the supply port, and a liquid feed section that circulates the cleaning liquid through the circulation path, and the filter can be attached to and detached from the pipe. The cleaning liquid circulating means can perform an operation of circulating the cleaning liquid through the circulation path in a state where the discharge port is sealed by the sealing means and the filter is removed from the pipe. Accordingly, by removing the nozzle from the mounting position of the coating apparatus after the cleaning liquid circulating means performs this operation, the operator can perform a predetermined operation on a relatively clean nozzle with a small amount of coating liquid attached. The cleaning liquid circulating means can perform an operation of circulating the cleaning liquid through the circulation path in a state where the discharge port is sealed by the sealing means and the filter is attached to the pipe. Accordingly, the cleaning liquid circulating means performs this operation after the nozzle is attached to the mounting position of the coating apparatus, so that the particles can be washed out from the internal space of the nozzle by the cleaning liquid circulating in the circulation path. In addition, since the filter is attached to the circulation path, the washed-out particles can be collected by the filter and the particles can be prevented from returning to the internal space of the nozzle. In this way, it is possible to remove particles adhering to the nozzle removed from the coating apparatus for a predetermined operation.

  A second aspect of the coating apparatus according to the present invention has a supply port that communicates with the internal space, a slit-shaped discharge port, and a discharge port, and a nozzle that discharges the coating liquid supplied from the supply port to the internal space through the discharge port. A nozzle support part that detachably supports the nozzle at the mounting location, a pipe that constitutes a circulation path that returns from the discharge port to the supply port, and a cleaning liquid that is provided in the pipe and has a lower viscosity than the coating liquid A cleaning liquid circulation means having a liquid feeding section to be circulated, a filter attached to the pipe, and a sealing means capable of sealing the discharge port of the nozzle. The nozzle is sealed by the sealing means. By discharging the coating liquid from the discharge port in a state where it is not stopped, the coating liquid is applied to the object, and the circulation path includes a first path that returns from the discharge port to the supply port without passing through the filter, and a drain path. After exiting the outlet and passing through the filter The cleaning liquid circulating means is configured to circulate the cleaning liquid through the first path in a state where the discharge port is sealed by the sealing means, and the discharge port is sealed by the sealing means. In this state, it is possible to selectively execute the operation of circulating the cleaning liquid through the second path.

  The coating apparatus configured in this manner applies the coating liquid to the object by discharging the coating liquid from the nozzle mounted at the attachment / detachment position of the nozzle support. That is, the nozzle has a supply port communicating with the internal space and a slit-shaped discharge port, and discharges the coating liquid supplied from the supply port to the internal space from the discharge port. Further, the nozzle has a discharge port communicating with its internal space, and the cleaning liquid circulating means cleans the nozzle by circulating the cleaning liquid through the supply port and the discharge port of the nozzle. The cleaning liquid circulation means includes a pipe constituting a circulation path that exits from the discharge port and returns to the supply port, and a liquid feeding section that circulates the cleaning liquid through the circulation path. The circulation path has a first path that returns from the discharge port to the supply port without passing through the filter, and a second path that returns from the discharge port to pass through the filter and then returns to the supply port. The cleaning liquid circulation means can execute an operation of circulating the cleaning liquid through the first path in a state where the discharge port is sealed by the sealing means. Accordingly, by removing the nozzle from the mounting position of the coating apparatus after the cleaning liquid circulating means performs this operation, the operator can perform a predetermined operation on a relatively clean nozzle with a small amount of coating liquid attached. Further, the cleaning liquid circulation means can execute an operation of circulating the cleaning liquid through the second path in a state where the discharge port is sealed by the sealing means. Accordingly, the cleaning liquid circulating means performs this operation after the nozzle is attached to the mounting position of the coating apparatus, so that the particles can be washed out from the internal space of the nozzle by the cleaning liquid circulating in the second path. In addition, since the filter is provided in the second path, the washed-out particles can be collected by the filter and the particles can be prevented from returning to the internal space of the nozzle. In this way, it is possible to remove particles adhering to the nozzle removed from the coating apparatus for a predetermined operation.

  As described above, according to the present invention, it is possible to remove particles adhering to the nozzle removed from the coating apparatus for a predetermined operation.

The perspective view which shows typically the coating device which concerns on this invention. The side view which shows the coating device shown in FIG. 1 typically. The top view which shows roughly arrangement | positioning of each part of the coating device shown in FIG. The perspective view which shows a slit nozzle typically. The perspective view which shows typically the decomposition | disassembly structure of the slit nozzle of FIG. The figure which shows typically the 1st example of the process liquid supply system with which a coating device is provided. The flowchart which shows an example of the nozzle cleaning process performed with a coating device. The figure which shows typically the 2nd example of the process liquid supply system with which a coating device is provided. The figure which shows typically the 3rd example of the process liquid supply system with which a coating device is provided.

  FIG. 1 is a perspective view schematically showing a coating apparatus according to the present invention. FIG. 2 is a side view schematically showing the coating apparatus shown in FIG. Further, FIG. 3 is a top view schematically showing the arrangement of each part of the coating apparatus shown in FIG. 1, 2, 3, and the subsequent drawings, an XYZ orthogonal coordinate system in which the Z direction is the vertical direction and the XY plane is the horizontal plane is appropriately attached and necessary to clarify the directional relationship. Accordingly, the dimensions and number of each part are exaggerated or simplified. Moreover, in FIG. 2 and FIG. 3, some structures, such as a nozzle support body, are abbreviate | omitted.

  The coating device 1 is a coating device called a slit coater that applies a coating solution to the surface 31 of the substrate 3 using the slit nozzle 2. The coating solution contains polyamic acid (polyamic acid) which is a polyimide precursor as a solute and NMP (N-Methyl-2-Pyrrolidone) as a solvent. The substrate 3 is a glass substrate having a rectangular shape in plan view. In the present specification, the “surface 31 of the substrate 3” means a main surface of the main surface of the substrate 3 on which the coating liquid is applied.

  The coating apparatus 1 includes a stage 4 that can hold the substrate 3 by suction in a horizontal posture, a coating processing unit 5 that applies a coating process to the substrate 3 held on the stage 4 using the slit nozzle 2, and the slit nozzle 2. A nozzle maintenance unit 6 that performs maintenance processing, a man-machine interface 7, and a control unit 100 that controls these units are provided.

  The stage 4 is made of a stone material such as granite having a substantially rectangular parallelepiped shape, and a holding surface 41 that holds the substrate 3 by processing it into a substantially horizontal flat surface on the −Y side of its upper surface (+ Z side). Have A large number of vacuum suction ports (not shown) are formed on the holding surface 41 in a dispersed manner. By adsorbing the substrate 3 through these vacuum suction ports, the substrate 3 is held horizontally at a predetermined position during the coating process. In addition, the holding | maintenance aspect of the board | substrate 3 is not limited to this, For example, you may comprise so that the board | substrate 3 may be hold | maintained mechanically. Further, a nozzle adjustment area RA is provided on the + Y side from the area occupied by the holding surface 41 in the stage 4, and a later-described nozzle maintenance unit 6 is disposed in the nozzle adjustment area RA.

  The coating processing unit 5 includes a nozzle support 51 that supports the slit nozzle 2. The nozzle support 51 includes a support member 51a that extends parallel to the X direction above the stage 4, and two lifting mechanisms 51b that support the support member 51a from both sides in the X direction and lift the support member 51a. Have The support member 51a is a bar member made of carbon fiber reinforced resin or the like and having a rectangular cross section. The lower surface of the support member 51 a is a mounting location 510 for the slit nozzle 2, and the support member 51 a supports the slit nozzle 2 in a detachable manner at the mounting location 510. As a mechanism for attaching / detaching the slit nozzle 2 to / from the mounting location 510 of the support member 51a, various fastening mechanisms such as a latch or a screw can be used as appropriate.

  The two elevating mechanisms 51b are connected to both ends of the fixing member 51a in the longitudinal direction, and each include an AC servo motor and a ball screw. By these elevating mechanisms 51b, the fixing member 51a and the slit nozzle 2 fixed to the fixing member 51a are moved up and down in the vertical direction (Z direction), and the interval between the discharge port 21 opened at the lower end of the slit nozzle 2 and the substrate 3, that is, the substrate The relative height of the discharge port 21 with respect to 3 is adjusted. The vertical position of the fixing member 51a is not shown, for example, but is provided on the scale portion provided on the side surface of the elevating mechanism 51b and the side surface of the slit nozzle 2 facing the scale portion. It can detect with the linear encoder comprised with the detected sensor.

  As shown in FIG. 1, the nozzle support 51 configured in this manner has a bridge structure that straddles the holding surface 41 spanning the left and right ends of the stage 4 along the X direction. The coating processing unit 5 includes a slit nozzle moving unit 53 that moves the nozzle support 51 in the Y direction. The slit nozzle moving unit 53 moves the nozzle support 51 as a bridging structure and the slit nozzle 2 supported thereby relative to the substrate 3 held on the stage 4 along the Y direction. Functions as a means. Specifically, the slit nozzle moving unit 53 includes a guide rail 52 that guides the movement of the slit nozzle 2 in the Y direction, a linear motor 54 that is a driving source, and a discharge port of the slit nozzle 2 on each of the ± X sides. And a linear encoder 55 for detecting the position 21.

  Each of the two guide rails 52 is provided at both ends in the X direction of the stage 4 and extends in the Y direction so as to include a section in which the nozzle adjustment region RA and the holding surface 41 are provided. The two guide rails 52 guide the movement of the two lifting mechanisms 51b in the Y direction, respectively. The two linear motors 54 are AC coreless linear motors provided on both sides of the stage 4 and having a stator 54a and a mover 54b. The stator 54a is provided on the side surface in the X direction of the stage 4 along the Y direction. On the other hand, the moving element 54b is fixed to the outside of the elevating mechanism 51b. Each of the two linear motors 54 drives the two lifting mechanisms 51b in the Y direction by a magnetic force generated between the stator 54a and the mover 54b.

  Each linear encoder 55 has a scale portion 55a and a detection portion 55b. The scale portion 55 a is provided along the Y direction below the stator 54 a of the linear motor 54 fixed to the stage 4. On the other hand, the detection unit 55b is fixed to the outer side of the moving element 54b of the linear motor 54 fixed to the elevating mechanism 51b, and is arranged to face the scale unit 55a. The linear encoder 55 detects the position of the discharge port 21 of the slit nozzle 2 in the Y direction based on the relative positional relationship between the scale unit 55a and the detection unit 55b.

  The slit nozzle moving unit 53 configured in this manner drives the nozzle support 51 in the Y direction so that the slit nozzle moves between above the nozzle adjustment region RA and above the substrate 3 held on the stage 4. 2 can be moved. The coating apparatus 1 forms a coating layer on the surface 31 of the substrate 3 by moving the slit nozzle 2 relative to the substrate 3 while discharging the coating liquid from the discharge port 21 of the slit nozzle 2. In addition, the area | region (frame-shaped area | region) of predetermined width from the edge part of each edge | side of the board | substrate 3 is a non-application area | region which is not the application object of a coating liquid. Accordingly, a rectangular area of the substrate 3 excluding the non-application area is an application area RT where the application liquid is to be applied (FIG. 3). For this reason, a coating liquid is discharged from the discharge port 21 which moves the upper area of the application | coating area | region RT of the board | substrate 3 among the movement areas of the slit nozzle 2. FIG.

  In addition, the slit nozzle 2 holds the substrate 3 during a period when the coating process is not performed on the stage 4 such as a delivery period of the substrate 3 between the coating apparatus 1 and the external transport mechanism (carrying-in / out period of the substrate 3). Retreat to the nozzle adjustment area RA deviated from the surface 41 to the + Y side (state shown in FIG. 1). And the nozzle maintenance unit 6 performs various maintenance with respect to the slit nozzle 2 located in the nozzle adjustment area | region RA.

  The nozzle maintenance unit 6 includes a standby pot 61, a sealing member 62, and a nozzle cleaning device 63 that are arranged in the Y direction in order from the far side from the holding surface 41. The standby pot 61 stores a cleaning liquid, and immerses the lower end of the slit nozzle 2, that is, the periphery of the discharge port 21, in the cleaning liquid. Therefore, by making the slit nozzle 2 face the standby pot 6, it is possible to suppress the component of the dried coating liquid from adhering to the lower end portion of the slit nozzle 2. The sealing member 62 contacts the lower end of the slit nozzle 2 from below to seal the discharge port 21 of the slit nozzle 2. By sealing the discharge port 21 with the sealing member 62, the discharge of the coating liquid from the discharge port 21 is prohibited. This sealing member 62 is mainly used in a later-described cleaning process for cleaning the slit nozzle 2 using a cleaning liquid. The nozzle cleaning device 63 removes the coating liquid adhering to the lower end portion of the slit nozzle 2, that is, around the discharge port 21. That is, the nozzle cleaning device 63 has a scraper 631 having a shape corresponding to the lower end portion of the slit nozzle 2, and the lower end portion of the slit nozzle 2 by sliding the scraper 631 to the lower end portion of the slit nozzle 2 in the X direction. Scrape off the coating solution.

  FIG. 4 is a perspective view schematically showing the slit nozzle, and FIG. 5 is a perspective view schematically showing an exploded structure of the slit nozzle of FIG. The slit nozzle 2 includes two nozzle bodies 23 and 25 and a nozzle shim 27 sandwiched between the nozzle bodies 23 and 25 from the Y direction. The nozzle bodies 23 and 25 are each extended with the same width in the X direction, and have trapezoidal lower end portions 23a and 25a and rectangular upper end portions 23b and 25b in the YZ section. The inner surfaces (nozzle shim 27 side) surfaces of the nozzle bodies 23 and 25 are each a plane parallel to the ZX plane. On the other hand, the outer surfaces (the opposite side of the nozzle shim 27) of the lower end portions 23a and 25a of the nozzle bodies 23 and 25 are inclined surfaces that are inclined so as to approach the nozzle shim 27 as they go downward. Therefore, the lower end portion 2a (nozzle lip portion) of the slit nozzle 2 constituted by the lower end portions 23a and 25a of the nozzle bodies 23 and 25 has a tapered shape downward.

  Further, a flow path F for the coating liquid is formed on the inner surface of the nozzle body 25. The flow path F has a horizontal hole portion Fa extending in parallel with the X direction and a vertical hole portion Fb extending in parallel with the Z direction from the center of the horizontal hole Fa. Then, both ends in the X direction of the lateral hole portion Fa open on both side surfaces of the nozzle body 25 to form side surface openings A1 and A2, respectively, and the upper end of the vertical hole portion Fb opens on the upper surface of the nozzle body 25 to open the upper surface. Configure A3.

  The nozzle shim 27 has a flat plate-like upper side portion 271 that extends in the X direction with the same width as the nozzle bodies 23 and 25, and a flat plate-shaped side portion 272 that extends downward from both ends of the upper side portion 271 in the Z direction. And have. A region below the upper side portion 271 and between the side side portions 272 functions as the cavity CV of the slit nozzle 2. The upper side portion 271 that defines the upper end of the cavity CV is located above the horizontal hole portion Fa of the flow path F, and the cavity CV communicates with the horizontal hole portion Fa of the flow path F. Further, the lower end of the cavity CV opens outward to form a slit-like discharge port 21. The cavity CV has the same width as the application region RT (FIG. 3) in the X direction. Thus, the nozzle shim 27 functions as an application width defining member that defines the application width of the discharge port 21.

  The coating apparatus 1 includes a processing liquid supply system S for supplying a processing liquid such as a coating liquid and a cleaning liquid to the slit nozzle 2. FIG. 6 is a diagram schematically illustrating a first example of a processing liquid supply system provided in the coating apparatus. As shown in the figure, the processing liquid supply system S includes a supply mechanism 8 that supplies the processing liquid to the slit nozzle 2 and a discharge mechanism 9 that discharges the processing liquid from the slit nozzle 2.

  The supply mechanism 8 includes a deaeration tank 81 connected to a coating liquid supply source U1 and a cleaning liquid supply source U2 that are storage tanks attached to the coating apparatus 1 via valves V1 and V2, respectively. The deaeration tank 81 temporarily stores the coating liquid supplied from the coating liquid supply source U1 or the cleaning liquid supplied from the cleaning liquid supply source U2, and removes dissolved gas in the coating liquid or the cleaning liquid. The cleaning liquid is NMP, which is a solvent for the coating liquid, and has a lower viscosity than the coating liquid. This cleaning liquid is mainly used in the cleaning process of the slit nozzle 2 described later.

  An air supply source U3 (utility) is connected to the deaeration tank 81 via a valve V3. Therefore, the control unit 100 opens the valve V1 to store the coating liquid in the deaeration tank 81, and then opens the valve V3 to pressure-feed air into the deaeration tank 81, thereby outputting the output unit 811 of the deaeration tank 81. The coating liquid can be pressed out from. Further, the control unit 100 opens the valve V2 to store the cleaning liquid in the deaeration tank 81, and then opens the valve V3 and pumps air into the deaeration tank 81, so that the output unit 811 of the deaeration tank 81 The washing liquid can be discharged.

  Further, the supply mechanism 8 has a pump 82 connected to the output portion 811 of the deaeration tank 81 by a pipe P1. The pump 82 is a fixed discharge pump such as a tube pump. The input part 821 of the pump 82 and the output part 811 of the deaeration tank 81 are connected by a pipe P1, and the pump 82 sucks the processing liquid pumped out from the deaeration tank 81 into the pipe P1 and outputs it. Output from the unit 822.

  Further, the supply mechanism 8 has a manifold 83, and an input portion 831 of the manifold 83 is connected to an output portion 822 of the pump 82 by a pipe P2. Of the two output portions 832 and 833 included in the manifold 83, the output portion 832 is connected to the side opening A1 of the slit nozzle 2 by a pipe P3 via a valve V4. Therefore, the control unit 100 can supply the processing liquid to the slit nozzle 2 via the manifold 83 by operating the pump 82 with the valve V4 opened.

  In the supply mechanism 8, the pressure gauge G 1 is attached to the pipe P 1 and the pressure gauge G 2 is attached to the manifold 83. The pressure gauge G1 is provided for monitoring the negative pressure level on the input side of the pump 82, and the pressure gauge G2 is provided for monitoring the positive pressure level on the output side of the pump 82. That is, when the negative pressure level or the positive pressure level becomes larger than the respective threshold values, the control unit 100 reduces the rotation speed of the pump 82, thereby suppressing the load on the pump 82.

  The discharge mechanism 9 includes a recycle tank 91 that temporarily stores the processing liquid discharged from the slit nozzle 2. The recycle tank 91 is connected to the side opening A2 of the slit nozzle 2 by a pipe P4 via a valve V5, and is connected to the upper face opening A3 of the slit nozzle 2 by a pipe P5 via a valve V6. A part of the pipes P4 and P5 on the recycle tank 91 side from the valves V5 and V6 is shared. Therefore, the control unit 100 can discharge the processing liquid discharged from the side surface opening A2 and the upper surface opening A3 of the slit nozzle 2 to the recycling tank 91 by opening the valves V5 and V6.

  Further, an air supply source U4 (utility) is connected to the recycle tank 91 via a valve V7. Therefore. The control unit 100 can press the processing liquid from the output unit 911 of the recycle tank 91 by opening the valve V7 and pumping air into the recycle tank 91. Further, the output unit 911 of the recycle tank 91 is connected to the pipe P1 of the supply mechanism 8 by a pipe P6 via a switching valve V8. The switching valve V8 is a three-way valve that selectively opens one of the two output parts v81 and v82. Among these output units v81 and v82, the output unit v81 is connected to the pipe P1 of the supply mechanism 8, and the output unit v82 is connected to the drain. Therefore, the control unit 100 can return the processing liquid discharged from the recycle tank 91 to the pipe P6 to the deaeration tank 81 of the supply mechanism 8 by opening the output unit v81 of the switching valve V8. By opening the output part v82 of the valve V8, this processing liquid can be discarded from the drain.

  As described above, in the processing liquid supply system S, the circulation path CR (circulation system) for returning the processing liquid from the side opening A2 and the top opening A3 of the slit nozzle 2 to the side opening A1 of the slit nozzle 2 is formed by the pipes P1 to P6. (That is, a circulation path CR (circulation system) for circulating the processing solution clockwise in FIG. 6 is configured). In addition, the filter 10 is detachably attached to the pipe P6. By removing the filter 10 from the pipe P6, a first circulation system (circulation path CR) that does not have the filter 10 can be configured, and the filter 10 By attaching to the pipe P6, a second circulation system (circulation path CR) having the filter 10 can be configured.

  Further, the processing liquid supply system S includes a pipe P7 that connects the output portion 833 of the manifold 83 and the recycle tank 91 via the valve V9. A part of the pipe P7 on the side of the recycle tank 91 from the valve V9 is shared with parts of the pipes P4 and P5 on the side of the recycle tank 91 from the valves V5 and V6.

  Then, when applying the coating liquid to the substrate 3, the control unit 100 supplies the coating liquid to the side surface opening A1 of the slit nozzle 2 with the valve V5 and the valve V6 closed. Thereby, in the slit nozzle 2, the coating liquid supplied from the side surface opening A1 spreads from the flow path F to the cavity CV and is discharged from the discharge port 21 (application process).

  In addition, when the coating apparatus 1 resumes operation from a long-term stopped state, the control unit 100 remains in the deaeration tank 81 by opening the valve V3 with the valves V1 and V2 closed. The coating liquid is discharged to the pipe P1. In parallel with this, the control unit 100 operates the pump 82 with the valves V4 to V6 closed and the valves V9 open, so that the coating liquid that has reached the manifold 83 from the pipe P1 passes through the pipes P2 and P7. To the recycling tank 91. Further, the control unit 100 discards the coating liquid sent to the deaeration tank 81 from the drain by opening the output unit v82 of the switching valve V8 while opening the valve V7.

  Further, the control unit 100 performs the nozzle cleaning process shown in FIG. 7 during a period when the coating process is not performed. Here, FIG. 7 is a flowchart showing an example of the nozzle cleaning process executed in the coating apparatus. Here, a case where the nozzle cleaning process is started after the coating process is finished will be described as an example. Therefore, before the start of the nozzle cleaning process, only the valve V4 is open, the other valves V2 to V7 and V9 are closed, and the output part v81 is open at the switching valve V8. Further, the pump 82 is stopped.

  When the flowchart of FIG. 7 is started, the slit nozzle 2 is moved above the sealing member 62, and the discharge port 21 of the slit nozzle 2 is sealed by the sealing member 62 (step S101). Subsequently, the valve V3 is opened and the valves V5 and V6 are opened. As a result, air supply to the degassing tank 81 is executed in a state where the supply of the coating liquid from the coating liquid supply source U1 to the degassing tank 81 is stopped, so that the pipes P1 to P3 and the slit nozzle 2 are provided. The remaining coating solution is sent to the recycle tank 91 via the pipes P4 and P5 (step S102). In parallel with this, the valve V7 is opened, the output part v82 of the switching valve V8 is opened, and the coating liquid sent to the recycle tank 91 is discarded from the drain.

  Subsequently, the first circulation cleaning process is executed (step S103). Specifically, the operation of the pump 82 is started and the valve V2 is opened, and the cleaning liquid from the cleaning liquid supply source U2 is supplied to the side opening A1 of the slit nozzle 2 via the pipes P1 to P3. In the slit nozzle 2, the cleaning liquid flows into the flow path F and the cavity CV from the side surface opening A1. At this time, since the discharge port 21 is sealed, the flowing cleaning liquid flows out from the side surface opening A2 and the upper surface opening A3, and is sent to the recycle tank 91 through the pipes P4 and P5. In parallel with this, the output part v81 of the switching valve V8 is opened, and the cleaning liquid that has reached the recycle tank 91 returns to the pipe P1 via the pipe P6. Thus, the flow path F and the cavity CV of the slit nozzle 2 can be cleaned by the cleaning liquid circulating in the circulation path CR without the filter 10, that is, the first circulation system.

  When the first circulation cleaning process is completed, the pump 82 is stopped and the valves V2 and V7 are closed, and the cleaning liquid circulating in the circulation path CR is collected in the recycle tank 91, and the pipes P1 to P1 are connected from the air supply source U3. Air (dry air) is introduced into P5 (air purge). Then, after the valve V3 is closed and the air purge is stopped, the man-machine interface 7 displays that the slit nozzle 2 can be removed (step S105).

  In response to this, the operator removes the slit nozzle 2 from the mounting location 510 of the nozzle support 51 and performs a predetermined manual operation (predetermined operation) on the slit nozzle 2 (step S106). The contents of this manual work include, for example, disassembling the slit nozzle 2 into parts 21, 23 and 25, and disassembling and cleaning the nozzle shim 27 in accordance with the application region RT in the application process to be executed next. The shim exchange work to exchange is mentioned. When the manual operation on the slit nozzle 2 is completed, the operator attaches the slit nozzle 2 to the mounting location 510 of the nozzle support 51 (step S107). When the operator inputs to the man-machine interface 7 that the slit nozzle 2 has been attached, the man-machine interface 7 performs a display requesting attachment of the filter 10 to the circulation path CR (step S108).

  When the operator inputs to the man-machine interface 7 that the filter 10 has been attached, the second circulating cleaning process is executed (step S109). Specifically, the operation of the pump 82 is started, the valve V7 is opened, and the cleaning liquid recovered in the recycle tank 91 is supplied to the side opening A1 of the slit nozzle 2 through the pipes P6 and P1 to P3. Is done. In the slit nozzle 2, the cleaning liquid flows into the flow path F and the cavity CV from the side surface opening A1. At this time, since the discharge port 21 is sealed, the flowing cleaning liquid flows out from the side surface opening A2 and the upper surface opening A3 and is sent to the recycle tank 91. Thus, the flow path F and the cavity CV of the slit nozzle 2 can be cleaned by the cleaning liquid circulating in the circulation path CR having the filter 10, that is, the second circulation system.

  When this second circulating cleaning process is completed, the output part v82 of the switching valve V8 is opened, and the cleaning liquid returned to the recycle tank 91 is discarded from the drain. Subsequently, the pump 82 is stopped and the output part v81 of the switching valve V8 is opened, and air (dry air) is introduced (purged) from the air supply source U4 to the pipes P6 and P1 to P5 (step S110). Subsequently, the man-machine interface 7 performs a display requesting removal of the filter 10 from the circulation path CR (step S111). Then, when the operator inputs to the man-machine interface 7 that the filter 10 has been removed, the pipes P1 to P5 and the slit nozzle 2 are filled with the coating liquid by opening the valves V1 and V3 while closing the valve V7 (step) S112).

  As described above, in the nozzle cleaning process (nozzle cleaning method) shown in FIG. 7, the nozzle 21 exits the side opening A2 and the top opening A3 and returns to the side opening A1 with the discharge port 21 of the slit nozzle 2 sealed. After the cleaning liquid is circulated in the first circulation system (first circulation cleaning process), the slit nozzle 2 is removed from the mounting location 510 of the coating apparatus 1. As a result, the operator can perform a predetermined manual operation on the relatively clean slit nozzle 2 with a small amount of coating liquid attached (step S106). Further, when the slit nozzle 2 on which the manual operation has been performed is attached to the mounting location 510 of the coating apparatus 1, the side opening is provided from the side opening A2 and the top opening A3 in a state where the discharge port 21 of the slit nozzle 2 is sealed. The cleaning liquid is circulated in the second circulation system that returns to A1 (second circulation cleaning process). Therefore, particles can be washed away from the flow path F and the cavity CV of the slit nozzle 2 by the cleaning liquid circulating in the second circulation system. Moreover, since the second circulation system has the filter 10 between the side opening A2 and the top opening A3 to the side opening A1, the washed particles are collected by the filter 10 and the particles are flown through the slit nozzle 2. Returning to F or cavity CV again can be suppressed. In this way, it is possible to remove particles adhering to the slit nozzle 2 removed from the coating apparatus 1 for manual work.

  Incidentally, in this embodiment, in the cleaning of the slit nozzle 2 before removing the slit nozzle 2 (first circulation cleaning process), the cleaning liquid is circulated in the first circulation system without the filter 10, whereas the slit In the cleaning of the slit nozzle 2 after the nozzle 2 is attached (second circulation cleaning process), the cleaning liquid is circulated in the second circulation system having the filter 10. One reason for properly using the filter 10 in this way is as follows. That is, the cleaning in the first circulation system is executed mainly to wash away the component (solute) of the coating liquid fixed to the flow path F of the slit nozzle 2 and the inner wall of the cavity CV with the cleaning liquid (solvent). Moreover, since the cleaning execution timing in the first circulation system is before the execution of the predetermined work by the operator, no particles exist in the first circulation system, and the filter 10 is not necessary in the first place. On the other hand, the cleaning in the second circulation system is executed mainly to remove particles adhering to the flow path F of the slit nozzle 2 and the inner wall of the cavity CV when the slit nozzle 2 is removed. If such particles return to the flow path F and the cavity CV of the slit nozzle 2 as the cleaning liquid circulates, the subsequent coating process is greatly affected. Therefore, in the cleaning in the first circulation system (first circulation cleaning process), the filter 10 is not used, so that the consumption of the filter 10 is suppressed, and in the cleaning in the second circulation system (second circulation cleaning process), the filter 10 is removed. It is supposed to collect particles by using it.

  In this embodiment, a cleaning liquid having a viscosity lower than that of the coating liquid is circulated through the circulation path CR. Therefore, a relatively fine filter 10 can be used, and particles can be efficiently collected by the filter 10.

  Further, in this embodiment, the slit nozzle 2 is cleaned by circulating the cleaning liquid while sealing the discharge port 21 of the slit nozzle 2, in other words, the cleaning liquid is circulated and used for nozzle cleaning. Therefore, consumption of the cleaning liquid can be suppressed.

  Furthermore, the cleaning liquid circulated in the first circulation cleaning process (step S103) is circulated in the second circulation cleaning process (step pS109). As described above, by using the cleaning liquid in common for the cleaning in the first circulating cleaning process and the cleaning in the second circulating cleaning process, consumption of the cleaning liquid can be more effectively suppressed.

  In addition, after the first circulation cleaning process (step S103), before removing the slit nozzle 2 from the mounting location 510, a step S104 for introducing dry air into the circulation path CR is provided. In such a configuration, the slit nozzle 2 can be removed after the cleaning liquid in the flow path F and the cavity CV of the slit nozzle 2 is pushed out by the gas introduced into the circulation path CR. As a result, the operator can perform manual work on the dried slit nozzle 2.

  In addition, after the second circulation cleaning process, step S110 for introducing dry air into the circulation path CR is provided. In such a configuration, the cleaning liquid in the flow path F and the cavity CV of the slit nozzle 2 can be pushed out by the dry air introduced into the circulation path CR. As a result, it is possible to suppress the cleaning liquid remaining in the flow path F and the cavity CV of the slit nozzle 2 from affecting the coating process to be executed later.

  In this embodiment, the coating solution contains a polyimide precursor and a solvent, and the cleaning solution is a solvent for the coating solution. Thus, since the coating liquid containing a polyimide precursor has high viscosity, it is easy to adhere to the flow path F of the slit nozzle 2 and the inner wall of the cavity CV. Therefore, it is not sufficient to perform cleaning as described in Patent Document 1, and it is highly necessary to perform manual cleaning. Therefore, the problem that particles adhere during manual work tends to occur. Therefore, as shown in FIG. 7, after the slit nozzle 2 is attached, the cleaning liquid (solvent) is circulated in the circulation path CR (second circulation system) having the filter 10, so that the flow path F and the cavity of the slit nozzle 2. It is particularly preferred to remove particles from the CV.

  FIG. 8 is a diagram schematically illustrating a second example of the processing liquid supply system provided in the coating apparatus. In the following, differences from the first example shown in FIG. 6 will be mainly described, and common points will be denoted by corresponding reference numerals, and description thereof will be omitted as appropriate. However, it goes without saying that the same effects as those of the first example can be obtained by providing the configuration common to the first example.

  The second example of FIG. 8 differs from the first example of FIG. 6 in the configuration of the circulation path CR. That is, in the circulation path CR of the second example, the switching valve V10 is attached to the pipe P6 between the switching valve V8 and the filter 10. The switching valve V10 is a three-way valve that selectively opens one of the two outputs v101 and v102. Of the two outputs v101 and v102 of the switching valve V10, the output v101 is connected to the output side of the filter 10 by the pipe P8, and the output v102 is connected to the input side of the filter 10.

  Therefore, when the output v101 of the switching valve V10 is opened, the processing liquid discharged from the recycle tank 91 to the pipe P6 bypasses the filter 10 and returns to the pipe P1 of the supply mechanism 8. On the other hand, when the output v102 of the switching valve V10 is opened, the processing liquid discharged from the recycle tank 91 to the pipe P6 passes through the filter 10 and then returns to the pipe P1 of the supply mechanism 8. Thus, the circulation path CR (circulation system) has the first path CR1 and the second path CR2 as paths that exit from the side surface opening A2 and the upper surface opening A3 of the slit nozzle 2 and return to the side surface opening A1 of the slit nozzle 2. Here, the first path CR1 is a path that exits from the side opening A2 and the upper surface opening A3 of the slit nozzle 2 and returns to the side opening A1 of the slit nozzle 2 without bypassing the filter 10 (bypass). CR2 is a path that exits from the side opening A2 and the top opening A3 of the slit nozzle 2 and passes through the filter 10 and then returns to the side opening A1 of the slit nozzle 2.

  In the processing liquid supply system S having such a configuration, the nozzle cleaning method of FIG. 7 can be executed by switching the output of the switching valve V10 between the output v101 and the output v102 instead of attaching and detaching the filter 10. That is, in the first circulation cleaning process of step S103, the cleaning liquid is circulated through the first path CR1 by opening the output v101 of the switching valve V10. Accordingly, the cleaning liquid is circulated in the first circulation system that does not have the filter 10, and the flow path F and the cavity CV of the slit nozzle 2 can be cleaned. In the second circulation cleaning process in step S109, the cleaning liquid is circulated through the second path CR2 by opening the output v102 of the switching valve V10. As a result, the cavity CV of the slit nozzle 2 can be cleaned by circulating the cleaning liquid in the second circulation system having the filter 10.

  FIG. 9 is a diagram schematically illustrating a third example of the processing liquid supply system provided in the coating apparatus. In the following, differences from the first example shown in FIG. 6 will be mainly described, and common points will be denoted by corresponding reference numerals, and description thereof will be omitted as appropriate. However, it goes without saying that the same effects as those of the first example can be obtained by providing the configuration common to the first example.

  The third example of FIG. 9 differs from the first example of FIG. 6 in that the pipe P3 is connected to the side opening A2 of the slit nozzle 2 by the pipe P9 between the valve V4 and the side opening A1 of the slit nozzle 2. It is a point. Further, the valve V5 and the pipe P4 provided in the first example do not exist in the third example. That is, the coating liquid output from the output part 832 of the manifold 83 is supplied to the side opening A1 and the side opening A2 via the valve V4. Therefore, in the slit nozzle 2 when performing the coating process, the coating liquid flowing into the flow path F from the side surface opening A1 and the side surface opening A2 spreads into the cavity CV and is discharged from the discharge port 21. On the other hand, in the slit nozzle 2 when the first circulating cleaning process (step S103) or the second circulating cleaning process (step S109) in FIG. 7 is performed, the cleaning liquid that has flowed into the flow path F from the side opening A1 and the side opening A2 is the upper surface. It is discharged from the opening A3.

  As described above, in the above-described embodiment, the coating apparatus 1 corresponds to an example of the “coating apparatus” of the present invention, the slit nozzle 2 corresponds to an example of the “nozzle” of the present invention, and the discharge port 21 corresponds to “ The side opening A1 of the first example (FIG. 6), the side opening A1 of the second example (FIG. 8), the side opening A1 and the side opening A2 of the third example (FIG. 9) correspond to an example of “discharge port”. It corresponds to an example of the “supply port” of the present invention, and the side surface opening A2, the upper surface opening A3 of the first example (FIG. 6), the side surface opening A2, the upper surface opening A3 of the second example (FIG. 8) and the third example (FIG. The upper surface opening A3 of 9) corresponds to an example of the “exhaust port” of the present invention, the flow path F and the cavity CV correspond to an example of the “internal space” of the present invention, and the nozzle support 51 corresponds to “ This corresponds to an example of “nozzle support”, and the mounting location 510 corresponds to an example of “mounting location” of the present invention. The liquid supply system S corresponds to an example of the “cleaning liquid circulation means” of the present invention, the circulation path CR corresponds to an example of the “circulation path” of the present invention, and the first path CR1 of the second example (FIG. 8) is the main line. The second route CR2 corresponds to an example of the “second route” of the present invention, the pipes P1 to P6 correspond to an example of the “pipe” of the present invention, the pump 82 corresponds to an example of the “liquid feeding part” of the present invention, the filter 10 corresponds to an example of the “filter” of the present invention, the sealing member 62 corresponds to an example of the “sealing means” of the present invention, The substrate 3 corresponds to an example of the “object” of the present invention, and the dry air corresponds to an example of “gas” of the present invention.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above embodiment, the cleaning liquid used in the first circulation cleaning process (step S103) is reused in the second circulation cleaning process (step S109). However, the cleaning liquid used in the first circulating cleaning process may be discarded after the first circulating cleaning process, and a new cleaning liquid may be used in the second circulating cleaning process.

  Various specific configurations of the pump 82 that is a drive source for circulating the coating liquid and the processing liquid in the circulation path CR are conceivable. Therefore, a pump other than the tube pump exemplified above may be used as the drive source.

  Further, the type of gas introduced into the circulation path CR in steps S104 and S110 is not limited to dry air, and may be nitrogen or the like, for example.

  The liquid that can be used as the cleaning liquid is not limited to the solvent of the coating liquid, that is, NMP. Therefore, other liquids such as thinner may be used as the cleaning liquid.

  Moreover, the liquid which can be utilized as a coating liquid is not restricted to the thing containing a polyimide precursor and NMP. Therefore, it is possible to use various coating liquids such as a photoresist liquid that forms an etching resistant coating, a photoresist liquid for color filters, a slurry (paste) containing silicon, nanometal ink, or a conductive material.

  Further, for the substrate 3 to be coated, a glass substrate for a liquid crystal display device, a semiconductor substrate, a glass substrate for a PDP, a glass substrate for a photomask, a substrate for a color filter, a substrate for a recording disk, a substrate for a solar cell, and an electronic paper Various substrates such as a substrate for precision electronic devices such as a substrate, a rectangular glass substrate, a flexible substrate for film liquid crystal, and a substrate for organic EL can be used.

  The present invention can be applied to all nozzle cleaning techniques for removing particles adhering to a nozzle.

  DESCRIPTION OF SYMBOLS 1 ... Coating device, 2 ... Slit nozzle, 21 ... Discharge port, A1 ... Side opening, A2 ... Side opening, A3 ... Top opening, F ... Flow path F, CV ... Cavity, 51 ... Nozzle support, 510 ... Installation location , S ... treatment liquid supply system, CR ... circulation path, CR1 ... first path, CR2 ... second path, P1-P9 ... piping, 82 ... decompression pump, 10 ... filter, 62 ... sealing member, 3 ... substrate,

Claims (7)

A nozzle having a supply port, a discharge port, and a discharge port communicating with the internal space is detachable from the mounting location, and the coating liquid is supplied to the internal space from the supply port of the nozzle attached to the mounting location. The supply port exits from the discharge port in a state where the discharge port of the nozzle attached to the mounting location of the coating apparatus that applies the coating liquid discharged from the discharge port of the nozzle to an object is sealed Circulating a cleaning solution having a viscosity lower than that of the coating solution in the first circulation system,
Removing the nozzle washed by circulation of the cleaning liquid in the first circulation system from the mounting location, performing a predetermined operation on the nozzle, and then attaching the nozzle to the mounting location;
In a state where the predetermined operation is performed and the discharge port of the nozzle attached to the mounting location is sealed, the discharge port exits from the discharge port and returns to the supply port, and between the discharge port and the supply port. And a step of circulating the cleaning liquid in a second circulation system having a filter.   The nozzle cleaning method according to claim 1, wherein the cleaning liquid circulated in the first circulation system is circulated in the second circulation system.   3. The method according to claim 1, further comprising a step of introducing a gas into the first circulation system after the cleaning liquid is circulated in the first circulation system and before the nozzle is removed from the mounting location. Nozzle cleaning method.   The nozzle cleaning method according to any one of claims 1 to 3, further comprising a step of introducing a gas into the second circulation system after the cleaning liquid is circulated in the second circulation system.   The nozzle cleaning method according to claim 1, wherein the coating liquid includes a polyimide precursor and a solvent, and the cleaning liquid is the solvent. A supply port that communicates with the internal space, a slit-like discharge port and a discharge port; a nozzle that discharges the coating liquid supplied from the supply port to the internal space from the discharge port;
A nozzle support that removably supports the nozzle at the mounting location;
A pipe that constitutes a circulation path that exits from the discharge port and returns to the supply port; a liquid feeding section that is provided in the pipe and circulates a cleaning liquid having a viscosity lower than that of the coating liquid through the circulation path; and the pipe A cleaning liquid circulating means having a detachable filter;
Sealing means capable of sealing the discharge port of the nozzle,
The nozzle applies the coating liquid to an object by discharging the coating liquid from the discharge port in a state where the sealing unit does not seal the discharge port,
The cleaning liquid circulating means is configured to circulate the cleaning liquid in the circulation path in a state where the discharge port is sealed by the sealing means and the filter is removed from the pipe, and the discharge port is sealed. An application device capable of selectively performing the operation of circulating the cleaning liquid through the circulation path while being sealed by means and the filter being attached to the pipe. A supply port that communicates with the internal space, a slit-like discharge port and a discharge port; a nozzle that discharges the coating liquid supplied from the supply port to the internal space from the discharge port;
A nozzle support that removably supports the nozzle at the mounting location;
A pipe that constitutes a circulation path that exits from the discharge port and returns to the supply port; a liquid feeding section that is provided in the pipe and circulates a cleaning liquid having a viscosity lower than that of the coating liquid through the circulation path; A cleaning liquid circulating means having an attached filter;
Sealing means capable of sealing the discharge port of the nozzle,
The nozzle applies the coating liquid to an object by discharging the coating liquid from the discharge port in a state where the sealing unit does not seal the discharge port,
The circulation path includes a first path that exits from the discharge port and returns to the supply port without passing through the filter, and a second path that exits from the discharge port and passes through the filter and then returns to the supply port. Have
The cleaning liquid circulating means is configured to circulate the cleaning liquid in the first path in a state where the discharge port is sealed by the sealing means, and in a state where the discharge port is sealed by the sealing means. A coating apparatus capable of selectively executing an operation of circulating the cleaning liquid in the second path.

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