JP5912375B2 - Coating liquid coating device - Google Patents

Description

  The present invention relates to a coating liquid coating apparatus that coats a substrate with a coating liquid.

  In the liquid crystal display panel manufacturing process, semiconductor manufacturing process, etc., an inkjet-type coating liquid coating is performed by coating a coating liquid such as an alignment film solution or a resist solution on the surface of the substrate to form a coating film such as an alignment film or a resist film The device is used.

  Such an ink jet type coating liquid coating apparatus includes a coating head in which a plurality of ejection openings are linearly arranged. Then, while relatively moving the coating head and the substrate, the coating liquid is ejected in droplets from each ejection port, and the coating liquid is applied to the surface of the substrate to form a coating film.

  In addition, such an ink jet type coating liquid coating apparatus is known which includes a suction cleaning means for removing the coating liquid adhering to the periphery of the ejection port in the coating head, that is, the ejection port forming surface by vacuum suction. (For example, see Patent Document 1).

  Such suction cleaning means cleans the discharge port forming surface by moving a suction cap as a suction cleaning member along the discharge port forming surface. That is, the suction surface of the suction cap and the discharge port forming surface are brought close to each other with a slight gap formed therebetween, and the suction cap on which the suction force is applied is moved along the discharge port forming surface. During this movement, the coating liquid adhering to the discharge port forming surface is removed by suction by the suction force applied to the suction cap.

  However, while there are various adhesion states such as the amount and distribution of the coating liquid adhering to the discharge port forming surface, the suction force acting on the suction cap is constant at a preset value, so that a good cleaning state is achieved. It was difficult to obtain stably.

JP 2004-306546 A

  An object of the present invention is to provide a coating liquid coating apparatus capable of satisfactorily cleaning the discharge port forming surface of a coating head by a suction cleaning member.

A coating liquid coating apparatus according to an embodiment of the present invention is a coating liquid coating apparatus that ejects a coating liquid from a plurality of ejection ports formed on a ejection port forming surface of a coating head and applies the coating liquid to a substrate.
A suction cleaning member for cleaning the discharge port forming surface by suction;
A controller for controlling the suction force applied to the suction cleaning member and the discharge operation of the coating liquid from the discharge port;
The control device drives the drive element of the coating head when the discharge operation from the discharge port performed immediately before the cleaning operation is a discharge operation for pumping the coating liquid and flowing it out of the discharge port. The suction force applied to the suction cleaning member is increased as compared with the discharge operation in which the coating liquid is discharged as droplets from the discharge port.

  According to the present invention, it is possible to satisfactorily clean the discharge port forming surface of the application head by the suction cleaning member.

It is a schematic front view which shows the whole structure of the coating liquid coating device which concerns on 1st Embodiment. FIG. 2 is a schematic plan view of FIG. 1. It is a schematic side view of FIG. It is a schematic block diagram which shows the principal part of the coating liquid coating device of FIG. It is a schematic diagram which shows the cleaning operation | movement of the discharge port formation surface by a suction cleaning part. It is a schematic diagram which shows an example of the adhesion state detection of the coating liquid by the coating liquid coating apparatus which concerns on 2nd Embodiment. It is a schematic diagram which shows the other example of the adhesion state detection of the coating liquid by the coating liquid coating apparatus which concerns on 2nd Embodiment.

  A first embodiment of the present invention will be described with reference to FIGS.

  The coating liquid coating apparatus 1 has a base 2 as shown in FIGS. On the base 2, a transfer table 4 is movably provided through a pair of guide rails 3 provided along the arrow Y direction.

  The transport table 4 is reciprocated along the Y-axis direction (the arrow Y direction in the drawing), which is the extending direction of the guide rail 3, by a drive mechanism (not shown). On the upper surface of the transfer table 4, a substrate W as an object to be coated is sucked and held by suction means such as vacuum suction or electrostatic chuck. Here, as the substrate W, for example, a rectangular glass substrate for manufacturing a display panel is used.

  A gate-type frame 5 that straddles the transport table 4 is provided at a substantially central position of the base 2 along an X-axis direction (arrow X direction in the drawing) orthogonal to the Y-axis direction. The portal frame 5 includes a support frame 6 having a rectangular frame shape in a plan view spanned between one leg and the other leg. A plurality of, in this embodiment, three application heads 7 are attached to the support frame 6 in a staggered arrangement along the X-axis direction.

  The coating head 7 is an inkjet coating head, and a plurality of ejection ports 7b (see FIG. 5B) are linearly arranged along the arrow X direction on the ejection port forming surface 7a on the lower surface thereof. Provided. Each of the discharge ports 7 b communicates with a liquid chamber (not shown) that stores a coating liquid in the coating head 7. The liquid chamber is provided with a flexible partition wall (not shown) that is deformed by a drive element (not shown) such as a piezoelectric element. Due to the volume change in the liquid chamber caused by the piezoelectric element being bent and deformed, the coating liquid is discharged from the discharge port 7b in the form of droplets.

  Such a coating head 7 can adjust the amount of liquid droplets discharged from the discharge port 7b by changing the magnitude of the drive voltage applied to the piezoelectric element, and can change the discharge frequency by changing the drive voltage application interval. (Discharge time interval) can be adjusted.

  The coating liquid is supplied to each coating head 7 by a coating liquid supply means (not shown). As the coating solution, for example, an alignment film solution for forming an alignment film, a resist solution for forming a resist film, or the like can be used.

  Further, a suction cleaning device 8 is provided at one end (the right end in FIGS. 1 and 2) in the moving direction (Y-axis direction) of the transport table 4. The suction cleaning device 8 includes a suction cleaning nozzle 9 as a suction cleaning member corresponding to each coating head 7.

  As shown in FIG. 4, each suction cleaning nozzle 9 includes a suction surface 9a at the upper end, and a slit-like suction hole 9b is formed in the suction surface 9a. The suction surface 9a is formed in a rectangular shape, and the long side direction is the Y-axis direction which is a direction orthogonal to the arrangement direction of the discharge ports 7b of the coating head 7, in other words, the discharge port forming surface of the coating head 7. It is arranged along the short side direction of 7a. The length of the long side of the suction surface 9a is longer than the length of the short side of the discharge port forming surface 7a by a predetermined length, and the length of the suction hole 9b formed in the suction surface 9a along the long side direction. The length is equal to or slightly longer than the length of the short side of the discharge port forming surface 7a (see FIG. 5B).

  Each suction cleaning nozzle 9 is supported by the X-axis direction moving device 10. These X-axis direction moving devices 10 are provided on a lifting plate 12 fixedly supported at the tip of an operating rod 11a of an air cylinder 11 as a lifting drive means. The air cylinder 11 is supported and fixed to a bracket member 13 having a substantially L-shaped cross section fixed to the side wall of the transport table 4. Thereby, each suction cleaning nozzle 9 can be moved in the Y-axis direction by the movement of the transport table 4, and is moved along the X-axis direction, that is, the arrangement direction of the discharge ports 7 b by driving the X-axis direction moving device 10. It is possible.

The suction cleaning device 8 includes a negative pressure supply device 14 for applying a suction force to the suction hole 9 b of the suction cleaning nozzle 9. The negative pressure supply device 14 is a vacuum pump 15 that generates a negative pressure, a vacuum pipe 16 that connects the vacuum pump 15 and the suction cleaning nozzle 9, and an electromagnetic opening and closing for supplying / stopping the negative pressure to the suction cleaning nozzle 9. The valve 17 (17a, 17b) , the electropneumatic regulator 18 (18a, 18b) for adjusting the magnitude of the negative pressure supplied to the suction cleaning nozzle 9, and the gas sucked by the suction cleaning nozzle 9 and the coating liquid are separated. A gas-liquid separator 19.

  That is, one end of the first vacuum pipe 16 a is connected to the suction hole 9 b of the suction cleaning nozzle 9. The other end of the first vacuum pipe 16 a is connected to the gas-liquid separator 19. The gas-liquid separator 19 is a tank having a predetermined volume, and the other end of the first vacuum pipe 16a penetrates the ceiling of the gas-liquid separator 19 in an airtight manner above the space in the tank. Open. Therefore, when the mixed fluid of the gas sucked from the suction hole 9b and the coating liquid is discharged from the other end portion (end portion on the gas-liquid separator 19 side) of the first vacuum pipe 16a, it is sufficient as compared with the gas. The heavier coating liquid drops and accumulates at the bottom of the gas-liquid separator 19. Thereby, gas and a coating liquid are isolate | separated. A drainage pipe 19b provided with an electromagnetic on-off valve 19a is connected to the bottom of the gas-liquid separator 19, so that the coating liquid accumulated in the gas-liquid separator 19 can be discharged.

In addition, one end of the second vacuum pipe 16 b is airtightly connected to the ceiling of the gas-liquid separator 19. The other end of the second vacuum pipe 16 b is connected to the vacuum pump 15. The second vacuum pipe 16b branches into two paths of a first pipe line 16b1 and a second pipe line 16b2 at the intermediate portion. Electromagnetic on-off valves 17a and 17b and electropneumatic regulators 18a and 18b are arranged in order from the vacuum pump 15 side in the two pipe lines 16b1 and 16b2, respectively. The adjustment amounts of the two electropneumatic regulators 18a and 18b are set so that the negative pressures supplied to the suction cleaning nozzle 9 are different from each other. Specifically, than adjusting the pressure of the first conduit 16 b 1 of the electropneumatic regulator 18a is towards the adjusting pressure electropneumatic regulator 18b of the second conduit 16b2 are adjusted to be lower. In other words, compared with the magnitude of the negative pressure (first vacuum suction force) supplied via the first pipe line 16 b 1, the negative pressure (first pressure) supplied via the second pipe line 16 b 2. The magnitude of the vacuum suction force (2) is increased.

  Further, the coating liquid coating apparatus 1 includes a control device 20. The control device 20 moves the transport table 4, discharges the coating liquid from the coating head 7, drives the X-axis direction moving device 10, opens / closes the electromagnetic open / close valves 17a, 17b, 19a, and adjusts by the electropneumatic regulators 18a, 18b. Control the pressure.

  Further, the control device 20 includes a storage unit 20a, and various data necessary for applying the coating liquid are stored in the storage unit 20a. The various data include, for example, a driving voltage for the piezoelectric element set to eject a predetermined amount of droplets from the ejection port 7b, coating pattern data indicating the coating position of the coating liquid droplets on the substrate W, The moving speed of the transfer table 4 and the pressure feeding conditions for forcibly discharging the coating liquid to recover clogging of the discharge port 7b due to bubbles, dust, and the like.

  Next, the operation will be described.

  In such a coating liquid coating apparatus 1, when the coating liquid is applied to the substrate W, first, the transport table 4 is carried in / out the work position of the substrate W on the guide rail 3 under the control of the control device 20 (FIG. 1). (Position on the left end side indicated by a broken line) in FIG. At this position, the substrate W is supplied onto the transfer table 4 by a transfer robot (not shown).

  The substrate W supplied onto the transport table 4 is sucked and held by a suction unit provided in the transport table 4.

  When the substrate W is held on the transfer table 4, the transfer table 4 moves toward the opposite end (right end) of the guide rail 3 at the moving speed stored in the storage unit 20 a under the control of the control device 20. To start.

  During the movement of the conveyance table 4, the control device 20 takes in the position information of the conveyance table 4 based on the output of a position detector (not shown) such as a linear encoder provided along with the guide rail 3. Based on this positional information, the control device 20 applies driving voltage to each piezoelectric element in accordance with the timing when the substrate W passes under the coating head 7 and is preset from each ejection port 7b of the coating head 7. A predetermined amount of droplets are ejected, and droplets of the coating liquid are applied onto the substrate W in a predetermined coating pattern.

When the substrate W passes under the coating head 7 and the transport table 4 reaches the right end of the guide rail 3 (position indicated by a solid line in FIG. 1), the movement of the transport table 4 is stopped.
Next, the transfer tail 4 is moved toward the left end, and is positioned at the loading / unloading work position of the substrate W.

  When the transfer table 4 is positioned at the loading / unloading work position, the substrate W after application is taken out from the transfer table 4 by a transfer robot (not shown), and a new substrate W is supplied to the transfer table 4.

  By repeating such operations, the coating liquid is sequentially applied to the plurality of substrates W.

  The coating liquid may be applied to the substrate W by passing the substrate W twice or more in addition to passing the substrate W under the coating head 7 once.

  In such a coating liquid coating apparatus 1, in order to maintain the ejection characteristics of droplets from the ejection port 7b at a constant characteristic, the ejection port forming surface 7a is periodically cleaned using the suction cleaning device 8. .

  Next, the cleaning operation of the discharge port forming surface 7a by the suction cleaning device 8 will be described.

  When cleaning the discharge port forming surface 7a, first, the transfer table 4 is positioned at the loading / unloading work position of the substrate W (the position on the left end side indicated by the broken line in FIG. 1). In this state, the suction cleaning device 8 that is integrally supported by the transport table 4 is positioned at a position facing (directly below) each coating head 7. Conditions for performing a cleaning operation are set in the storage unit 20a, and the control device 20 sets the transport table 4 so that the suction cleaning member 8 performs cleaning when the conditions set in the storage unit 20a are met. Position at the loading / unloading work position. Here, as conditions for performing the cleaning operation, “after applying the coating liquid to the substrate W described above”, “forcibly discharging the coating liquid for recovering clogging of the discharge port 7b due to bubbles or the like was executed. "After" or "After executing a dummy discharge for preventing the coating liquid from drying at the discharge port 7b when the standby time for stopping the discharge of the coating liquid continues for a predetermined time or longer".

  When the transfer table 4 is carried in / out, that is, when the suction cleaning device 8 is positioned at a position facing each coating head 7, the air cylinder 11 is driven by the control device 20, and the lifting plate 12 is in the state shown in FIG. Is moved from the standby position to the working position raised from that position. As shown in FIG. 5A, the vertical direction (Z-axis direction) is formed between the suction surface 9a of the suction cleaning nozzle 9 and the discharge port forming surface 7a in a state where the elevating plate 12 is positioned at the work position. A slight gap is formed. Further, at this stage, the suction cleaning nozzle 9 is positioned at a standby position located on one side of the coating head 7 in the X-axis direction of the discharge port 7b, which is the position shown in FIG.

  Here, FIG. 5 shows a state in which the coating liquids L1 and L2 adhere to the ejection port forming surface 7a of the coating head 7, and one coating head 7 and a suction cleaning nozzle 9 corresponding to the coating head 7 are provided. It is an enlarged view. 5A is a view of the coating head 7 as viewed from the lateral direction, and FIG. 5B is a view of the coating head 7 as viewed from below (the direction facing the discharge port forming surface 7a). The suction surface 9a and the suction hole 9b of the suction cleaning nozzle 9 are indicated by a two-dot chain line.

  When the elevating plate 12 is raised to the working position, a vacuum suction force is applied to the suction hole 9b of the cleaning suction nozzle 9. That is, one of the electromagnetic open / close valve 17a and the electromagnetic open / close valve 17b is controlled to open, and the vacuum suction force generated by the vacuum pump 15 and adjusted by the electropneumatic regulators 18a and 18b is applied to the suction hole 9b. At this time, the vacuum pump 15 may be always driven, or may be driven when the control device 20 determines that the condition for performing the cleaning operation stored in the storage unit 20a is satisfied. In the latter case, the driving of the vacuum pump 15 is preferably stopped when the cleaning operation is completed.

  When a vacuum suction force is applied to the suction hole 9b, the X-axis direction moving device 10 is driven, and the suction cleaning nozzle 9 moves from one side of the coating head 7 in the X-axis direction toward the other side. In the example shown in FIG. 5A, the suction cleaning nozzle 9 moves from the right side indicated by the solid line to the coating head 7 to the left side indicated by the two-dot chain line.

  During the movement in the X-axis direction, the suction cleaning nozzle 9 sucks and removes the coating liquid adhering to the discharge port forming surface 7a of the coating head 7 by a vacuum suction force acting on the suction hole 9b. The sucked coating liquid is sent to the gas-liquid separator 19 through the first vacuum pipe 16a. The coating liquid sent to the gas-liquid separator 19 falls from the first vacuum pipe 16 a and is stored at the bottom of the gas-liquid separator 19.

  When the suction cleaning nozzle 9 reaches the other side of the application head 7, the electromagnetic on-off valves 17a and 17b are closed and the vacuum suction force applied to the suction hole 9b is stopped.

  After the vacuum suction is stopped, the air cylinder 11 is driven and the elevating plate 12 is lowered to the standby position. When the elevating plate 12 is positioned at the standby position, the X-axis direction moving device 10 is driven and the suction cleaning nozzle 9 is returned to the standby position.

  By such an operation, the coating liquid adhering to the discharge port forming surface 7a of the coating head 7 is removed.

Therefore, in the coating liquid coating apparatus 1 of the present embodiment, the magnitude of the suction force that acts on the suction hole 9b of the suction cleaning nozzle 9 during the above-described cleaning operation is set to the discharge performed immediately before the cleaning operation. Switching is performed based on the discharge operation from the outlet 7b. That is, the first pipe line 16 b 1 and the second pipe line 16 b 2 depend on which of the conditions for performing the cleaning operation set in the storage unit 20 a the discharge operation performed immediately before. The vacuum suction force is applied to the suction hole 9b by properly using the above.

The amount of the coating liquid adhering to the ejection port forming surface 7a is relatively small in the ejection operation in which the coating liquid is ejected in the form of droplets from the ejection port 7b, as indicated by reference numeral L1 in FIG. In the discharge operation for forcibly discharging the coating liquid by flowing down from the discharge port 7b in order to recover clogging and the like, it has been experimentally confirmed that it becomes relatively large as indicated by a symbol L2 in FIG. Therefore, among the conditions set in the storage unit 20a, for example, after the application of the application liquid to the substrate W and after the dummy discharge corresponding to the ejection operation, the first pipeline 16 b 1 The first vacuum suction force is applied to the suction hole 9b via the. On the other hand, it corresponds to the discharge operation, after executing the forcible discharge of the coating liquid, so as to impart a second vacuum suction force through the second conduit 16 b 2 to the suction hole 9b.

  Here, the ejection operation is an ejection operation in which the coating liquid is ejected in the form of droplets from the ejection port 7b by driving the piezoelectric element, and the discharge operation is from the coating liquid supply means (not shown) side. This is a discharge operation in which the coating liquid is pumped and discharged from the discharge port 7b by driving the pump or gas pressure.

  In such a first embodiment, when the discharge operation performed immediately before the cleaning operation is a spray operation in which the amount of coating liquid adhering to the discharge port forming surface 7a is relatively small, the suction hole 9b The vacuum suction force to be applied was defined as the first vacuum suction force. Further, when the discharge operation performed immediately before the cleaning operation is a discharge operation in which the amount of the coating liquid adhering to the discharge port forming surface 7a is relatively large, the vacuum suction force applied to the suction hole 9b is set to the first suction force. The second vacuum suction force was larger than the vacuum suction force. That is, the vacuum suction force applied to the suction hole 9b is switched in accordance with the amount of the coating liquid attached to the discharge port forming surface 7a of the coating head 7. Therefore, the coating liquid adhering to the discharge port forming surface 7a can be removed favorably.

  That is, if the vacuum suction force applied to the suction hole 9b is too strong with respect to the amount of coating liquid applied to the discharge port forming surface 7a, the discharge port forming surface is caused by the flow of air along the discharge port forming surface 7a caused by vacuum suction. 7a will dry too much. On the contrary, the vacuum suction force applied to the suction hole 9b is too weak, and the coating liquid adhering to the discharge port forming surface 7a cannot be sufficiently removed and remains. If the discharge port forming surface 7a is too dry, the coating solution in the discharge port 7b is likely to dry, and discharge failure due to solidification of the coating solution in the discharge port 7b tends to occur. Further, if the coating liquid adhering to the discharge port formation surface 7a cannot be sufficiently removed and remains, the ejection amount of the droplets from the discharge port 7b varies, or the ejected droplets do not fly straight and are bent. This causes a discharge failure. Therefore, by switching the vacuum suction force applied to the suction hole 9b according to the amount of the coating liquid attached to the discharge port forming surface 7a, the cause of the discharge failure as described above can be eliminated. The outlet forming surface 7a can be kept in a state suitable for the droplet discharge operation, in particular, the jet operation, and the droplet ejection characteristics from the discharge port 7b can be maintained in a good state. Therefore, the coating liquid can be satisfactorily applied to the substrate W, and as a result, the quality of the coating pattern such as a coating film formed on the substrate W can be improved.

  Next, a second embodiment will be described with reference to FIGS.

  In the second embodiment, a detection device 21 is provided as a detection means for detecting the application state of the coating liquid to the discharge port forming surface 7a of the coating head 7, and is applied to the suction hole 9b based on the detection result of the detection means. This is different from the first embodiment in that the vacuum suction force to be switched is switched.

  As shown in FIG. 6, the detection device 21 includes an imaging unit such as a camera 21a and an image processing device 21b.

  The camera 21a is arranged at a position facing the discharge port forming surface 7a of the coating head 7 in a state where the discharge port forming surface 7a can be imaged. For example, the camera 21a extends the bracket member 13 in the horizontal direction toward the side opposite to the conveyance table 4, and is provided with the suction cleaning device 8 one by one in correspondence with each coating head 7 on the extension. Can do. In such a configuration, prior to cleaning by the suction cleaning device 8, the camera 21a is opposed to the discharge port forming surface 7a of the coating head 7 and an image of the discharge port forming surface 7a (see FIG. 6B) is taken. To do. The captured image G by the camera 21a is transmitted to the image processing device 21b.

  The image processing device 21b performs image processing on the captured image G of the camera 21a, and extracts images of the coating liquids L1 and L2 attached to the discharge port forming surface 7a. Such extraction can be performed, for example, by previously registering an image of the discharge port forming surface 7a to which the coating liquid is not attached as a template image and taking the difference between the template image and the captured image G. It is. Based on the image data of the coating liquids L1 and L2 extracted in this way, the image processing device 21b calculates the adhesion amounts of the coating liquids L1 and L2. For example, the maximum length (lengths s1, s2 in the X-axis direction) and the maximum width (lengths d1, d2 in the Y-axis direction) of the coating liquid are calculated as the adhesion amount. Information on the calculated lengths s 1 and s 2 and widths d 1 and d 2 is sent to the control device 20.

  The control device 20 applies a vacuum suction force to the suction hole 9b through the first pipe line 16a1 based on the transmitted information on the lengths s1 and s2 and the widths d1 and d2 of the coating liquids L1 and L2. Or whether it is given via the second pipe line 16a2.

  That is, the control device 20 compares the transmitted lengths s1 and s2 and the widths d1 and d2 with the set values of the length and the width stored in advance in the storage unit 20a. If both the length and width are equal to or less than the set values, it is determined that the amount of the coating liquid attached is small, and the first vacuum suction force is applied to the suction hole 9b via the first pipe line 16a1. Give. When either the length or the width exceeds the set value, it is determined that the amount of the coating liquid deposited is large (a larger amount than the small amount), and the second is passed through the second conduit 16a2. The vacuum suction force is applied to the suction hole 9b.

  By doing so, similarly to the first embodiment, even when the amount of the coating liquid adhering to the discharge port forming surface 7a is large or small, the vacuum applied to the suction hole 9b according to the amount of adhering. Since the suction force is switched, it is possible to satisfactorily remove the coating liquid adhering to the discharge port forming surface 7a.

  As shown in FIG. 7, the detection device 21 is a camera that can image the discharge port forming surface 7 a from the horizontal direction (horizontal direction) in a state where the optical axis is aligned with the discharge port forming surface 7 a of the coating head 7. 21a may be arranged. At this time, for example, one camera 21a can be provided on the support frame 6 that supports the coating head 7 in correspondence with each coating head 7 via an attachment or the like. In the case of such a configuration, prior to cleaning by the suction cleaning device 8, an image (see FIG. 7B) of the discharge port forming surface 7a is taken from the lateral direction by the camera 21a.

  The image processing device 21b extracts images of the coating liquids L1 and L2 attached to the ejection port formation surface 7a from the captured image G by the same method as described with reference to FIG. Based on the image data of L2, the image processing device 21b calculates the adhesion amounts of the coating liquids L1 and L2. For example, the maximum thickness of the coating liquid (lengths h1 and h2 in the Z-axis direction) is calculated as the adhesion amount. Information on the calculated thicknesses h1 and h2 is sent to the control device 20.

  The control device 20 compares the transmitted thicknesses h1 and h2 with, for example, a preset thickness value stored in the storage unit 20a. When the thickness is equal to or less than the set value, it is determined that the amount of the coating liquid to be attached is small, and a first vacuum suction force is applied to the suction hole 9b through the first pipe line 16a1. Further, when the thickness exceeds the set value, it is determined that the amount of the coating liquid attached is large (a larger amount than the small amount), and the second vacuum suction force is set via the second pipe line 16a2. It is made to give to the suction hole 9b.

  Also in this way, as in the first embodiment, even when the amount of the coating liquid adhering to the discharge port forming surface 7a is large or small, it is applied to the suction hole 9b according to the amount of adhesion. Since the vacuum suction force is switched, it is possible to satisfactorily remove the coating liquid adhering to the discharge port forming surface 7a.

  In the above description, the conditions for applying a small vacuum suction force (first vacuum suction force) to the suction holes 9b are the image lengths of the coating liquids L1 and L2 (lengths s1 and s2 in the X-axis direction) and width. (Y-axis direction lengths d1 and d2) are both set values or less. However, the present invention is not limited to this. For example, one of the length and width selected in advance is less than the set value. In some cases, either the length or the width may be equal to or less than the set value. Alternatively, the length and width of the images of the coating liquid L1 and L2, or the length or width may be calculated at a plurality of locations, and the average value may be compared with the set value.

  Further, the length and width of the images of the coating liquids L1 and L2 were obtained and compared with the set values, or the thickness of the images of the coating liquids L1 and L2 were obtained and compared with the set values. The area of the image may be calculated, and the calculated area may be compared with the set value. At this time, the areas of the images of the coating liquids L1 and L2 can be obtained by multiplying the number of pixels corresponding to the images of the coating liquids L1 and L2 by the area of the unit pixel.

  Furthermore, the determination result based on the captured image captured from the direction facing the discharge port forming surface 7a as shown in FIG. 6 and the captured image captured from the lateral direction of the discharge port forming surface 7a as shown in FIG. It is also possible to switch the vacuum suction force acting on the suction hole 9b by combining the determination results based on the above. For example, the lengths (lengths s1, s2 in the X-axis direction) and widths (lengths d1, d2 in the Y-axis direction) of the coating liquids L1, L2 are both equal to or less than the set values, and the thicknesses h1, h2 are set. When it is less than the value, the vacuum suction force applied to the suction hole 9b is set to a small vacuum suction force (first vacuum suction force). In other cases, the vacuum suction force applied to the suction hole 9b is set to a large vacuum suction force (second vacuum suction force).

  In the second embodiment, the vacuum suction force applied to the suction hole 9b is switched by detecting the actual adhesion amount of the coating liquid to the discharge port forming surface 7a. For this reason, a small vacuum suction force (first vacuum suction force) is applied when the adhesion amount of the coating liquid is small, and a second vacuum suction force (a second vacuum suction force greater than the first vacuum suction force) is large when the adhesion amount of the coating liquid is large. Therefore, the coating liquid can be removed with a vacuum suction force suitable for the actual amount of the coating liquid adhering to the discharge port forming surface 7a. Therefore, as in the first embodiment, the discharge port forming surface 7a can be maintained in a state suitable for the droplet discharge operation, particularly the jet operation, and the droplet discharge characteristics from the discharge port 7b are excellent. It becomes possible to maintain the state. Therefore, the coating liquid can be satisfactorily applied to the substrate W, and as a result, the quality of the coating pattern such as a coating film formed on the substrate W can be improved.

  In the above-described embodiment, the vacuum suction force applied to the suction hole 9b is constant during one cleaning operation, that is, while the suction cleaning nozzle 9 moves from one side of the coating head 7 to the other side. Although an example of values has been described, the present invention is not limited to this, and may be variable. For example, as shown in FIG. 6 or FIG. 7, images of the coating liquids L1 and L2 attached to the discharge port forming surface 7a are captured using the camera 21a. Next, the width or thickness of the images of the coating liquids L1 and L2 is calculated at a plurality of locations along the moving direction of the suction hole 9b. The calculated width or thickness is compared with a set value stored in advance in the storage unit 20a, and the vacuum suction force acting on the suction hole 9b is set to the other portion where the width or thickness exceeds the set value. You may control so that it may become large compared with. By doing in this way, even if there are a portion with a large amount and a small amount of the coating liquid adhering on the discharge port forming surface 7a, the difference in the partial amount of adhering vacuum suction force that acts on the suction hole 9b. Therefore, the coating liquid can be removed favorably from the discharge port forming surface 7a.

  Alternatively, as the tendency of the adhesion shape of the coating liquid to the discharge port forming surface 7a, regardless of whether the amount of adhesion is large or small, the both ends of the central portion of the discharge port forming surface 7a in the longitudinal direction (moving direction of the suction cleaning nozzle 9). When there is a tendency that the amount of adhesion tends to be increased, the vacuum suction force applied to the suction hole 9b may be controlled to be larger at the center portion than at both end portions. Even in this case, the coating liquid can be satisfactorily removed from the discharge port forming surface 7a as described above.

  Moreover, although the example which made the suction cleaning nozzle 9 movable to the long side direction of the discharge port formation surface 7a was demonstrated, it is not restricted to this, The suction cleaning nozzle 9 is made to the short side direction of the discharge port formation surface 7a. You may make it move along. In this case, the length of the suction hole 9b of the suction cleaning nozzle 9 is preferably equal to or slightly longer than the length of the discharge port forming surface 7a in the long side direction. In addition, in the case of such an arrangement, when there is a tendency that the adhesion amount of the coating liquid (the thickness of the coating liquid) tends to increase along the portion where the ejection port 9b is formed on the ejection port forming surface 7a, During the movement of the suction cleaning nozzle 9 along the short side direction of the discharge port forming surface 7a, the vacuum suction force applied to the suction hole 9b is made larger at the discharge port 9b forming portion than at the other portions. You may control.

  In addition, the detection device 21 has been described as having a configuration using the camera 21a, but is not limited thereto, and may be, for example, a configuration using a line sensor or a displacement sensor. When the line sensor is used, it is preferable to obtain a planar image of the coating liquids L1 and L2 attached to the discharge port forming surface 7a by moving the line sensor along the discharge port forming surface 7a. When a displacement sensor is used, the displacement sensor is moved in a lattice pattern along the discharge port forming surface 7a, so that the discharge port is formed based on the height difference between the discharge port forming surface 7a and the surfaces of the coating liquids L1 and L2. It is preferable to obtain three-dimensional information of the coating liquids L1 and L2 attached to the surface 7a.

DESCRIPTION OF SYMBOLS 1 Coating liquid coating device 4 Conveyance table 7 Coating head 7a Discharge port formation surface 7b Discharge port 8 Suction cleaning device 9 Suction cleaning nozzle (suction cleaning member)
9a Suction surface 9b Suction hole 14 Negative pressure supply device 15 Vacuum pump 16 Vacuum piping 16a First vacuum piping 16b Second vacuum piping 17 Electromagnetic on-off valve 18 Electropneumatic regulator 19 Gas-liquid separator 20 Control device 21 Detection device means)
21a Camera 21b Image processing apparatus

Claims (1)

In a coating liquid coating apparatus that discharges a coating liquid from a plurality of ejection openings formed on the ejection port forming surface of a coating head and applies the coating liquid to a substrate.
A suction cleaning member for cleaning the discharge port forming surface by suction;
A controller for controlling the suction force applied to the suction cleaning member and the discharge operation of the coating liquid from the discharge port;
The control device drives the drive element of the coating head when the discharge operation from the discharge port performed immediately before the cleaning operation is a discharge operation for pumping the coating liquid and flowing it out of the discharge port. A coating liquid coating apparatus characterized in that a suction force applied to the suction cleaning member is increased as compared with a discharging operation in which the coating liquid is discharged as droplets from a discharge port .

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