JP2014057930A - Coating device and operation method of coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating device quick in a return up to starting coating treatment from a standby state, while reducing a discharge quantity of a coating liquid in the standby state.SOLUTION: In the coating device for coating the coating liquid on a substrate, coating of the coating liquid to the substrate is executed by moving a nozzle above the substrate while continuously discharging the coating liquid from the nozzle in a state of keeping opening constant, after controlling the opening of a coating liquid flow passage so that a coating liquid flow rate substantially coincides with a target value, and in standby time up to new coating after finishing the coating, pressure applied to the coating liquid is restrained more than coating time in a coating liquid supply part while keeping a continuous discharge state of the coating liquid from the nozzle while keeping the opening of the coating liquid flow passage in the same as the coating time of the coating liquid, and the new coating is executed after controlling the opening of the coating liquid flow passage so that the coating liquid flow rate substantially coincides again with the target value, after returning the pressure applied to the coating liquid in the coating liquid supply part to the same as the coating time.

Description

  The present application relates to a coating apparatus that applies a liquid material to a flat coating target, and more particularly, to operation control when the coating apparatus is returned from a standby state.

  For example, in the manufacture of an organic EL display device using an organic EL (Electro Luminescence) material, a fluid material containing the organic EL material is applied to a coating target region set on the glass substrate for the display device. Is widely used as a coating apparatus that applies a coating liquid to a coating object in a stripe shape by relatively moving the coating object and the nozzle while simultaneously discharging the coating liquid from a large number of nozzles (for example, Patent Document 1). reference).

JP 2012-071270 A

  In the conventional coating apparatus as disclosed in Patent Document 1, normally, the state in which the coating liquid is discharged from the nozzle is maintained even when the coating operation is not performed (during standby). This is caused by clogging of the nozzle due to drying of the coating liquid inside the nozzle, or collapse of the liquid column due to adhesion of the coating liquid near the tip of the nozzle (formation of the liquid column). This is to avoid the occurrence of intermittent phenomenon).

  However, in this case, since the discharged coating liquid is not used, the amount of the discharged coating liquid needs to be suppressed as much as possible within a range where the liquid column does not collapse.

  On the other hand, in order to perform a new coating processing operation, it is necessary to return the coating apparatus from a standby state in which the discharge amount is suppressed to a state where coating processing is possible. However, if time is required for such recovery, productivity decreases. .

  The present invention has been made in view of the above problems, and an object of the present invention is to realize a coating apparatus that can quickly return from the standby state to the start of the coating process while reducing the discharge amount of the coating liquid in the standby state.

  In order to solve the above problems, the invention of claim 1 is a coating apparatus for coating a substrate with a coating liquid, a holding unit for holding the substrate, a nozzle for discharging the coating liquid, and a nozzle movement for moving the nozzle. A mechanism, a storage section for storing the coating liquid, and a coating liquid supply section for supplying the coating liquid to the nozzle through a coating liquid flow path by applying pressure to the coating liquid stored in the storage section; The coating liquid is applied to the substrate after the opening of the coating liquid channel is controlled so that the flow rate of the coating liquid substantially matches a predetermined target value. The nozzle is moved above the substrate while the coating liquid is continuously discharged from the nozzle in a state where the pressure is kept constant, and after the coating of the coating liquid is completed, a new coating is performed. During standby, The pressure applied to the coating liquid in the coating liquid supply unit while maintaining the continuous discharge state of the coating liquid from the nozzle while keeping the opening degree of the cloth liquid channel the same as that during the application of the coating liquid. In the new application, the pressure applied to the application liquid in the application liquid supply unit is returned to the same value as in the application, and the flow rate of the application liquid again becomes a predetermined target value. It is characterized by controlling the opening degree of the coating liquid flow path so as to substantially match.

  A second aspect of the present invention is the coating apparatus according to the first aspect, wherein a flow rate measuring unit that measures a flow rate of the coating liquid flowing through the coating liquid channel and an opening that defines an opening degree of the coating liquid channel. An opening degree control unit that controls the opening degree of the coating liquid flow path in the opening degree defining part based on the measurement result of the flow rate of the coating liquid in the flow rate measurement part, and for the substrate The application liquid is applied after the opening degree control unit controls the opening degree of the application liquid flow path in the opening degree defining part so that the flow rate of the application liquid substantially matches a predetermined target value. The nozzle is disposed above the substrate while the coating liquid is continuously discharged from the nozzle while the control of the opening degree defining unit by the degree control unit is stopped and the opening degree of the coating liquid channel is kept constant. Is performed, and after the application of the coating liquid, During standby until a new application is performed, the opening degree of the coating liquid channel is kept the same as that during the application of the coating liquid by stopping control of the opening degree defining unit by the opening degree control unit. While maintaining the continuous discharge state of the coating liquid from the nozzle, the pressure applied to the coating liquid in the coating liquid supply unit is suppressed more than that during the coating, and the new coating is applied to the coating liquid supply unit. After the pressure applied to the coating liquid is returned to the same as that at the time of coating, the opening degree control unit re-applies the application at the opening degree defining unit so that the flow rate of the coating liquid substantially coincides with a predetermined target value. It is characterized by controlling the opening of the liquid flow path.

  Invention of Claim 3 is a coating device of Claim 1 or Claim 2, Comprising: At the time of the said standby, the pressure added to the said coating liquid in the said coating liquid supply part is 0.75 times or more at the time of application | coating It is characterized by suppressing to the range.

  Invention of Claim 4 is a coating device in any one of Claim 1 thru | or 3, Comprising: The coating liquid supply connected to the said nozzle and deform | transforms following the movement of the said nozzle by the said nozzle moving mechanism A coating liquid supply tube constituting a part of the coating liquid flow path.

  The invention according to claim 5 is an operating method of a coating apparatus that applies a coating liquid onto a substrate by discharging a coating liquid from the nozzle while moving the nozzle, and the supply of the coating liquid to the nozzle Applying pressure to the coating liquid stored in a reservoir connected to the nozzle through a path, and applying the coating liquid to the substrate substantially matches the flow rate of the coating liquid with a predetermined target value. After controlling the opening degree of the coating liquid channel so that the opening degree of the coating liquid channel is kept constant, the coating liquid is continuously discharged from the nozzle while the opening degree of the coating liquid channel is kept constant. This is performed by moving the nozzle, and after the application of the coating liquid is completed and in a standby state until a new application is performed, the opening degree of the coating liquid channel is kept the same as that during the application of the coating liquid. Before from the nozzle The pressure applied to the coating liquid in the coating liquid supply unit is kept lower than that during the coating while maintaining a continuous discharge state of the coating liquid, and the new coating is applied to the coating liquid in the coating liquid supply unit Is performed after the opening degree of the coating liquid flow path is controlled so that the flow rate of the coating liquid substantially coincides with a predetermined target value.

  According to the first to fifth aspects of the present invention, it is possible to realize a coating apparatus that can quickly return from the standby operation to the start of a new coating while reducing the discharge amount of the coating liquid in the standby state after the coating process is completed. .

  In particular, according to the invention of claim 3, it is possible to reduce the discharge amount of the coating liquid in the standby state without causing the collapse of the liquid column.

It is a top view which shows the schematic structure of the coating device 1 which concerns on this Embodiment. It is a front view which shows the schematic structure of the coating device 1 which concerns on this Embodiment. It is a top view which shows roughly the board | substrate 100 with which the coating liquid was apply | coated. FIG. 3 is a schematic cross-sectional view showing components of the head moving mechanism 21 cut along a YZ plane. FIG. 4 is a schematic diagram showing a connection relationship between a pressurized tank 24 and a plurality of nozzles 23. 3 is a schematic diagram showing a configuration of a mass flow controller 62. FIG. It is a figure which shows the procedure of the coating process which the coating device 1 performs. It is a figure which shows the setting aspect of the original pressure of the pressurization tank 24, and the state of the control valve 622 from the completion | finish of an application | coating process until a next application | coating process is started through a standby state. It is a figure which illustrates the setting mode of the original pressure of the pressurized tank 24 and the state of the control valve 622 different from this Embodiment. It is a figure which shows the specific example of the change of the discharge pressure in the nozzle 23 in the case of standby pressure suppression standby. It is a figure which shows the specific example of the change of the discharge pressure in the nozzle in the case of a flow volume suppression standby. It is a figure which shows a time-dependent change about the value which normalized the discharge weight per unit time when the original pressure of the pressurized tank in a standby state is changed. It is a figure which shows the structure of the experimental apparatus 1000 schematically. In the experimental apparatus 1000, it is a figure which illustrates the time-dependent change of a discharge weight value when the nozzle which discharges a coating liquid with a fixed flow rate is closed only for fixed time CT.

<Schematic configuration of coating apparatus>
FIG. 1 and FIG. 2 are a plan view and a front view showing a schematic configuration of a coating apparatus 1 according to the present embodiment, respectively. The coating apparatus 1 according to the present embodiment is an apparatus that applies a predetermined coating liquid according to the application to a rectangular substrate 100 in plan view.

  As shown in FIGS. 1 and 2, the coating apparatus 1 includes a substrate holding unit 10 that holds the substrate 100, a substrate moving mechanism 11 that moves the substrate 100 by moving the substrate holding unit 10, and the substrate holding unit 10. The coating head 20 for applying the coating liquid to the coating target surface 100s of the substrate 100 held on the head, the head moving mechanism 21 for reciprocatingly moving the coating head 20 in a horizontal plane, and the coating liquid for storing the coating liquid The pressure tank 24 which is a storage part, and the control part 8 which controls operation | movement of each component of the coating device 1 are mainly provided.

  In the following, the reciprocating direction of the coating head 20 is a main scanning direction, and the direction orthogonal to the main scanning direction in the horizontal plane is a sub-scanning direction. In FIGS. 1 and 2, right-handed XYZ coordinates are provided with the main scanning direction as the X-axis direction, the sub-scanning direction as the Y-axis direction, and the vertical direction (vertical direction) as the Z-axis direction. (The same applies to FIGS. 3 and 4).

  In the present embodiment, the substrate 100 is a glass substrate for an organic EL display device, and the coating device 1 applies a coating solution containing a volatile solvent or an organic EL material as a light emitting material to the substrate 100. An explanation will be given for the case where In such a case, a plurality of linear application target areas are set at a predetermined pitch (for example, 100 μm to 150 μm) on the application target surface 100 s of the substrate 100, and each application target area includes a pair of application target areas. It is assumed that it is provided as a groove section that is sandwiched between partition walls (not shown). However, the aspect of providing the partition is not essential, and the application target area is set on the uniformly flat application target surface 100s without the partition, and the application liquid is applied to the application target area. Also good.

  However, the coating apparatus 1 can also apply glass substrates for various applications and substrates made of other materials as well as substrates for electronic devices. In such a case, a coating liquid corresponding to the type and application of the substrate is appropriately selected and applied.

  The substrate holding unit 10 is a mounting unit that holds the substrate 100 on the upper surface 10s thereof in a substantially horizontal posture. As shown in FIGS. 1 and 2, the substrate 100 is arranged such that the application target surface 100 s faces the positive z-axis direction, and the extension direction of the application target region coincides with the X-axis direction, which is the main scanning direction. Then, it is placed on the substrate holder 10.

  The substrate moving mechanism 11 is provided at a predetermined interval in the X-axis direction, and has two (a pair of) rails 12 extending along the Y-axis direction, and is guided by the rails 12 in the Y-axis direction. A base 13 is provided that is movable, and a turntable 14 that is provided on the upper surface of the base 13 and supports the substrate holding unit 10 and is rotatable in a horizontal plane.

  The substrate holding unit 10 is movable in the Y-axis direction, which is the sub-scanning direction, by moving the base 13 in the Y-axis direction. Further, the substrate holder 10 can be rotated in a horizontal plane by rotating the turntable 14 within a predetermined range about the vertical direction (Z-axis direction).

  The coating head 20 includes a plurality of nozzles 23 for continuously discharging the coating liquid stored in the pressurized tank 24. The plurality of nozzles 23 are mounted on the coating head 20 so as to be arranged at equal intervals in the sub-scanning direction with their tips directed vertically downward (Z-axis negative direction). Although details will be described later, the pressurized tank 24 and each nozzle 23 are connected by a coating liquid supply tube 64 and other piping. As shown in FIG. 1, the coating liquid supply tube 64 is bundled into one except for the vicinity of the connection portion with the nozzle 23. Hereinafter, a plurality of coating liquid supply tubes 64 and an air supply tube which will be described later are bundled together and referred to as a tube group 26.

  In the present embodiment, the case where the coating head 20 has five nozzles 23 is illustrated, but the number of nozzles 23 mounted on the coating head 20 is not limited to this, and is at least one or more. The nozzle 23 may be mounted on the coating head 20. Further, the nozzles 23 do not necessarily have to be arranged at equal intervals.

  FIG. 3 is a plan view schematically showing the substrate 100 on which the coating liquid has been applied by moving the coating head 20 in the main scanning direction. In the coating apparatus 1, each time the coating head 20 moves in the main scanning direction by the action of the head moving mechanism 21, that is, every time the coating head 20 moves from one end side to the other end side of the substrate 100 in the X-axis direction. The coating liquid is continuously discharged from the nozzle 23 to the corresponding application target area, and the application to the application target area is performed.

  More specifically, the coating head 20 maintains a state in which the flow (liquid column) of the coating liquid formed by discharging the coating liquid from the tip of the nozzle 23 vertically downward is continuously formed. By moving the position where the tip of the liquid column reaches the application target surface, the application of the application liquid to the linear application target region is realized.

  As shown in FIG. 3, in the case of the present embodiment, every time the coating head 20 moves in the main scanning direction, coating is performed on five coating target regions, and five coating films are formed in a stripe shape. The

  More specifically, the coating apparatus 1 includes two liquid receiving portions 17 and 18 adjacent to both end portions of the substrate holding portion 10 in the X-axis direction. This is performed by moving the coating head 20 between one liquid receiving part 17 and the other liquid receiving part 18. The liquid receivers 17 and 18 have an opening at a position corresponding to the movement path of the nozzle 23, and receives the coating liquid discharged from the nozzle 23 to the outside of the surface of the substrate 100 through the opening, Can be stored. The application liquid stored in the liquid receiving units 17 and 18 may be discarded, or may be appropriately collected and reused.

  In order to suitably follow the movement of the coating head 20 described above, each coating liquid supply tube 64 and the like constituting the tube group 26 is made of a flexible material.

  The control unit 8 is configured by a general computer, which is not shown in the figure, and is connected to a program storage medium such as a CPU and a ROM, a RAM, and the like by a bus. In the coating apparatus 1, the operation of each unit is controlled by the control unit 8 by reading a program stored in a storage medium such as a ROM and executing it in the CPU. Thereby, the coating treatment operation in the coating apparatus 1 is realized. Preferably, the control unit 8 is configured so that the control content of each component can be appropriately changed in response to an instruction input from an operator via an input unit (not shown). The actual connection between the control unit 8 and the components of the coating apparatus 1 that is the control target may be wired or wireless.

  Preferably, the coating apparatus 1 includes a pair of imaging units 15 above the substrate holding unit 10. The imaging unit 15 is provided in correspondence with the formation position of the alignment mark on the coating target surface 100 s of the substrate 100 in order to capture an alignment mark (not shown) formed in advance on the coating target surface 100 s of the substrate 100. In FIGS. 1 and 2, the imaging unit 15 is placed in the X-axis direction above the substrate holding unit 10 so as to correspond to the alignment marks formed at both ends in the X-axis direction of the application target surface 100 s. The case where it arrange | positions mutually spaced apart is illustrated. The imaging unit 15 includes a CCD camera, for example.

<Details of application head movement>
Next, the movement mode of the coating head 20 by the head moving mechanism 21 will be described in more detail. FIG. 4 is a schematic cross-sectional view showing the components of the head moving mechanism 21 cut along the YZ plane. The head moving mechanism 21 includes a pair of guide portions 22 that extend in the X-axis direction. The head moving mechanism 21 includes a substantially rectangular parallelepiped slider 31. The slider 31 is provided with two through holes 32 penetrating in the X axis direction so as to be separated from each other in the Y axis direction, and the guide portions 22 are loosely inserted in the respective through holes 32.

  In addition, air of a predetermined pressure is supplied to the slider 31 through an air supply tube bundled together with the tube group 26 from the air supply source 25 shown in FIG. As indicated by an arrow A1 in FIG. 4, the air is ejected from the plurality of ejection holes 32 h provided on the inner circumferential surface of the through hole 32 toward the outer circumferential surface of the guide portion 22. Thereby, the slider 31 and the guide part 22 are maintaining the non-contact state.

  On the other hand, as shown in FIG. 1, the head moving mechanism 21 includes a pair of pulleys 33 configured to be rotatable about the Z-axis direction as a rotation axis in the vicinity of both ends of the pair of guide portions 22. An endless synchronous belt 34 is wound around the pair of pulleys 33 in a stretched state. Further, a slider 31 is attached to the synchronization belt 34. More specifically, as shown in FIG. 4, the slider 31 has a coating head 20 attached to one side with respect to the Y-axis direction and a synchronization belt 34 attached to the other side.

  With the above configuration, in the coating apparatus 1, the coating head 20 is reciprocated in the X-axis direction by driving a motor (not shown) to rotate the synchronous belt 34 clockwise or counterclockwise. Can be done. In such a case, as described above, the slider 31 and the guide portion 22 are not in contact with each other. Therefore, even when the moving speed is relatively high, the movement of the coating head 20 is smooth. .

  The configuration of the head moving mechanism 21 described above is merely an example, and the coating apparatus 1 may be configured to move the coating head 20 by another method.

<Details of coating liquid discharge operation>
Subsequently, the discharge operation of the coating liquid from the nozzle 23 will be described in more detail. FIG. 5 is a schematic diagram showing a connection relationship between the pressurized tank 24 and the plurality of nozzles 23.

  As shown in FIG. 5, an electropneumatic regulator 61 is connected to the pressurized tank 24 for feeding the coating liquid and feeding the coating liquid to the nozzle 23. The electropneumatic regulator 61 is supplied with pressure adjusting gas (for example, nitrogen gas) from a supply source (not shown). The electropneumatic regulator 61 adjusts the pressure of the supplied nitrogen gas to a predetermined value and supplies it to the pressurized tank 24.

  Although not shown, the pressurized tank 24 has a resin pack in which the coating liquid is stored. In the pressurized tank 24, the internal pressure is increased by the nitrogen gas supplied from the electropneumatic regulator 61, and the resin pack is compressed. Thereby, the coating liquid stored in the resin pack is supplied to the outside of the pressurized tank 24 from the pipe 241 a at a flow rate corresponding to the pressure (applied pressure) applied to the pressurized tank 24. In addition, the container which stored the coating liquid in the pressurized tank 24 is arrange | positioned, and the liquid level of the coating liquid in a container is pressed by the internal pressure by nitrogen gas, and it goes out of a pressurized tank from the pipe connected to the container. It is good also as a structure which supplies a coating liquid. The pressure applied to the pressurized tank 24 in these cases is also referred to as a source pressure.

  The pipe 241a branches into a plurality of branch pipes 241b (the number corresponding to the number of nozzles 23) on the downstream side. A mass flow controller (MFC) 62 is provided in the middle of each branch pipe 241b. Further, an electromagnetic on-off valve (operation valve) 63 is provided at the tip of the branch pipe 241b, and a coating liquid supply tube 64 is connected to the downstream side of the electromagnetic on-off valve 63. The coating liquid supply tube 64 is connected to the nozzle 23 as described above. That is, in the coating apparatus 1, the pressurized tank 24, the pipe 241a, the branch pipe 241b, the coating liquid supply tube 64, and the nozzle 23 form a coating liquid flow path in this order. In addition, the part except the coating liquid supply tube 64 among coating liquid flow paths is fixedly provided in the coating apparatus 1, and does not have flexibility.

  The coating liquid stored in the pressurized tank 24 is pumped toward the mass flow controller 62 by the action of the electropneumatic regulator 61. Then, after the flow rate of the coating liquid is adjusted by the mass flow controller 62, the coating liquid is supplied to the nozzle 23 via the electromagnetic opening / closing valve 63 and the coating liquid supply tube 64.

  FIG. 6 is a schematic diagram showing the configuration of the mass flow controller 62. The mass flow controller 62 includes a mass flow meter 621 that is a flow rate measuring unit that measures the flow rate of the coating liquid flowing through the coating liquid channel, a control valve 622 that is an opening degree defining unit that can vary the opening degree of the coating liquid channel, And a valve control unit 623 which is an opening degree control unit for controlling the control valve 622.

  6 illustrates a configuration in which the control valve 622 is provided on the upstream side and the mass flow meter 621 is provided on the downstream side in the mass flow controller 62, but the arrangement of both can be changed as appropriate, and the upstream A mass flow meter 621 may be provided on the side.

  In any case, the mass flow meter 621 measures the flow rate of the coating liquid at a position upstream of the coating liquid flow channel from the coating liquid supply tube 64. That is, the mass flow meter 621 is arranged so as to measure the flow rate at a position where the influence of the deformation of the coating liquid supply tube 64 accompanying the movement of the nozzle 23 is relatively small.

  The mass flow meter 621 is, for example, a thermal flow sensor, and detects the temperature difference between the upstream side and the downstream side in the coating liquid flow path and performs a predetermined calculation to thereby apply the coating liquid that passes through the coating liquid flow path. Measure the flow rate. However, the mass flow meter 621 may be configured to measure the flow rate by other methods such as a differential pressure type flow meter that measures based on a pressure difference or an impeller type flow meter that measures using an impeller. .

  The control valve 622 is a flow rate control valve configured by an electric valve, for example. By providing such a valve, the opening degree (opening area) of the coating liquid channel can be adjusted well. It should be noted that the opening degree defining part is not necessarily constituted by a valve such as the control valve 622 and may have any configuration as long as the opening degree of the coating liquid channel can be adjusted. For example, the aspect which adjusts the opening degree of the coating liquid flow path in the cross section of the said pressure response part by comprising a part of coating liquid flow path with a flexible tube, and adjusting the force which presses a tube from the outside It may be.

  The valve control unit 623 is configured by a general computer to which a program storage medium such as a CPU and a ROM, a RAM, and the like are connected, which are not illustrated. In the valve control unit 623, a program stored in a storage medium such as a ROM is read out and executed by the CPU, whereby the control valve 622 based on a detection signal representing the measurement result obtained in the mass flow meter 621 is obtained. Control is realized. In addition, the coating device 1 may be configured such that the control unit 8 includes all or part of the function of the valve control unit 623.

  When the valve control unit 623 controls the control valve 622 to adjust the opening, a detection signal indicating a flow value is output from the mass flow meter 621 to the valve control unit 623. Based on the detection signal, the valve control unit 623 controls the control valve 622 to adjust the opening degree in the coating liquid flow path. Specifically, a flow rate detection signal is compared with a reference signal indicating an ideal flow rate. Then, the valve control unit 623 controls the control valve 622 so as to increase or decrease the opening degree in the coating liquid flow path (specifically, the branch pipe 241b) according to the comparison result. Control.

  In the present embodiment, the state in which the valve control unit 623 controls the control valve 622 based on the flow rate detection signal in the mass flow meter 621 is referred to as a “servo state”.

  On the other hand, a state in which the control of the control valve 622 by the valve control unit 623 is stopped and the opening degree in the coating liquid channel is fixed is referred to as a “hold state”.

  The electromagnetic on-off valve 63 is a part responsible for opening and closing the branch pipe 241b. The opening / closing operation of the electromagnetic opening / closing valve 63 is controlled by the control unit 8. The electromagnetic on-off valve 63 allows the coating liquid to pass by opening the branch pipe 241b, and prohibits the passage of the coating liquid by closing the branch pipe 241b. By providing the electromagnetic opening / closing valve 63 in each of the branch pipes 241b, it is possible to control the on / off of the discharge of the coating liquid from each of the plurality of nozzles 23. However, a mode in which the electromagnetic opening / closing valve 63 is provided in the branch pipe 241b is not essential. The electromagnetic on-off valve 63 may be provided in the middle of the pipe 241a, for example.

  Note that the branch pipe 241b can be opened and closed by controlling the control valve 622. Therefore, the electromagnetic on-off valve 63 can be omitted. However, by providing the electromagnetic opening / closing valve 63, the passage of the coating liquid can be more reliably blocked.

  However, in the present embodiment, normally, the coating liquid is continuously discharged from the nozzles 23 even when the coating operation is not performed (during standby). Details thereof will be described later. Therefore, the discharge of the coating liquid in the coating apparatus 1 is stopped only in exceptional cases, such as when the apparatus is stopped for a long period of time or when the apparatus is stopped for a long time for parts replacement, inspection, or the like.

<Coating operation>
FIG. 7 is a diagram illustrating a procedure of a coating process performed by the coating apparatus 1. In the following description, the operation of each component of the coating apparatus 1 is controlled by the control unit 8 unless otherwise specified. The operation of placing the substrate 100 on the substrate holding unit 10 and moving the substrate 100 to a position where the coating process can be performed and the returning operation of the coating apparatus 1 from a standby state to be described later start the procedure shown in FIG. It has already been completed before.

  When the execution instruction of the coating process is given by the operator, first, the position of the coating head 20 is initialized (step S11). Specifically, the head moving mechanism 21 moves the coating head 20 to an initial position above the liquid receiving unit 17. At this time, the upper position of the liquid receiving unit 18 may be determined as the initial position. At this time, the arrangement position of the substrate holding unit 10 in the Y-axis direction is adjusted so that the coating liquid is discharged from the nozzle 23 to the corresponding application target area when the coating head 20 moves in the X-axis direction. It becomes.

  When the position of the coating head 20 is initialized, flow control of the coating liquid discharged from the nozzle 23 is started (step S12). In detail, when the original pressure is lower than the specified value, by adjusting the electropneumatic regulator 61 to increase it to the specified value, and when the original pressure meets the specified value In the meantime, the control valve 622 is in a servo state while maintaining this. Then, the valve control unit 623 adjusts the opening degree of the control valve 622 based on the detection signal of the mass flow meter 621 so that the flow rate of the coating liquid supplied to the nozzle 23 becomes a target value. That is, the opening degree adjustment of the control valve 622 by the valve control unit 623 is performed in a state where the nozzle 23 is stopped at a position off the application target surface 100 s of the substrate 100.

  During the flow rate adjustment control, the coating liquid discharged from the nozzle 23 is collected by the liquid receiving unit 17 (or the liquid receiving unit 18).

  When the control unit 8 determines that the flow rate detected by the mass flow meter 621 substantially matches the target value (for example, when it is determined that the difference between the detected flow rate and the target value is smaller than a predetermined value), the flow rate adjustment control The control valve 622 is switched from the servo state to the hold state (step S13). That is, the control of the control valve 622 by the valve control unit 623 is stopped, and the opening degree of the control valve 622 is fixed. For example, it is preferable that the flow rate adjustment control be terminated when the difference between the flow rate detected by the mass flow meter 621 and the target value is 10 kPa or less.

  When the flow rate adjustment control is completed, the movement of the coating head 20 in the main scanning direction is started above the substrate 100 (step S14). Specifically, when the head moving mechanism 21 is driven, the coating head 20 moves from the position on the liquid receiving part 17 (or the liquid receiving part 18) to the opposite liquid receiving part 18 (or the liquid receiving part 17). ) Move to the upper position in the positive X-axis direction (or in the negative X-axis direction). During the movement of the coating head 20, the coating liquid is discharged from the plurality of nozzles 23 to the coating target surface 100 s of the substrate 100. Thereby, the coating liquid is applied to a plurality of application target areas corresponding to the number of the plurality of nozzles 23.

  As described above, in the present embodiment, prior to application of the application liquid by the nozzle 23, application of the application liquid by the nozzle 23 is performed while the application liquid of a predetermined flow rate is discharged by the flow rate adjustment control in the servo state. Is performed in a hold state in which the opening degree of the control valve 622 provided upstream of the nozzle 23 is fixed. This is to suppress fluctuations in the discharge amount from the nozzle 23 to the substrate 100 during application of the coating liquid.

  More specifically, during the coating process, since the coating head 20 periodically moves in the main scanning direction, the coating liquid supply tube 64 that follows this is bent and deformed, or the coating head 20 and the coating liquid supply Due to the fact that the coating liquid in the tube 64 is accelerated or decelerated in the main scanning direction, a periodic volume fluctuation occurs in the coating liquid flow path, or the coating liquid in the coating liquid supply tube 64 is periodically inertial. Force acts. This volume fluctuation and inertial force are factors that fluctuate the discharge amount of the coating liquid from the nozzle 23.

  If it is attempted to apply the coating liquid while maintaining the servo state, due to the influence of these volume fluctuations and inertial force, the actual discharge volume of the coating liquid discharged from the nozzle 23 and the mass flow meter 621 provided upstream of the nozzle 23. This causes a problem in that the amount of discharge from the nozzle 23 cannot be properly controlled.

  Therefore, in the present embodiment, as described above, the coating liquid is applied to the substrate 100 in the hold state.

  Preferably, the head moving mechanism 21 moves the coating head 20 while accelerating while the nozzle 23 is on the liquid receiving unit 17 (or the liquid receiving unit 18) immediately after the movement starts, and the nozzle 23 is above the substrate 100. In some cases, the coating head 20 is moved at a constant speed (for example, 3 m / second to 5 m / second). While the coating head 20 moves at a constant speed, the coating liquid is discharged from the nozzle 23 and applied to the substrate 100. After passing over the substrate 100, the coating head 20 is decelerated and stops on the liquid receiver 18 (or the liquid receiver 17). Thereby, a coating liquid is apply | coated relatively uniformly with respect to the application | coating area | region. Note that the speed of the coating head 20 does not necessarily have to be constant at the time of coating, and the speed may be changed as appropriate.

  When the application head 20 stops on the liquid receiving unit 17 (or the liquid receiving unit 18), the control unit 8 determines whether or not the application to all the application target areas set on the substrate 100 is completed. Specifically, it is determined whether or not the movement of the coating head 20 in the main scanning direction is completed a predetermined number of times when the coating to all the coating target areas is completed (step S15). The number of times is determined according to the number of nozzles 23 and the number of application target areas to be applied.

  If the application to all the application target areas has not been completed (No in step S15), the substrate moving mechanism 11 moves the substrate holding unit 10 holding the substrate 100 by a predetermined pitch in the sub-scanning direction. In the axial direction, the position of the application target region where the coating liquid is to be applied next is matched with the position of the nozzle 23. Then, again, the application head is moved in the main scanning direction to apply the application liquid. In such a case, the moving direction of the coating head 20 in the main scanning direction is opposite to the moving direction in the previous coating. That is, in the coating apparatus 1, the coating liquid can be applied to a new coating target area each time the coating head 20 moves alternately between the liquid receiving unit 17 and the liquid receiving unit 18. Yes.

  When it is determined that the application to all the application target regions is completed, that is, when the movement of the application head 20 in the main scanning direction is completed a predetermined number of times (Yes in step S15), the application process is performed. The operation ends.

  When the coating operation is completed, the coated substrate 100 is transported to a predetermined unloading position by the substrate moving mechanism 11 moving the substrate holding unit 10, and then unloaded to the outside of the apparatus.

<Operation control and return operation in standby state>
As described above, in the present embodiment, the coating liquid from the nozzle 23 is also applied when the coating apparatus 1 is in a standby state after the completion of a series of coating processing operations until the next coating processing is performed. The discharge is maintained without being stopped.

  This is caused by clogging of the nozzle 23 due to drying of the coating liquid inside the nozzle 23, or collapse of the liquid column due to the coating liquid adhering to the vicinity of the tip of the nozzle 23. This is to avoid the occurrence of problems such as the occurrence of intermittent liquid column formation) and the reduction of productivity due to the time required to return to the state where the coating treatment is possible. In addition, even when the liquid column collapses, for example, when the nozzle that discharges the coating liquid at a discharge flow rate of about several tens of μl / min to 200 μl / min is closed for only a short time of 10 to 20 seconds, It can happen at a certain frequency.

  FIG. 8 shows how the original pressure in the pressurized tank 24 and the state of the control valve 622 are set from the end of the coating process to the start of the next coating process in the present embodiment. FIG. Moreover, FIG. 9 is a figure which illustrates the setting aspect different from this Embodiment shown for comparison. The setting mode illustrated in FIG. 9 is a mode determined to be assumed in Patent Document 1. 8 and 9, Vh indicates that the control valve 622 is in the hold state, and Vs indicates that the control valve 622 is in the servo state.

  As shown in FIG. 8, in the case of the present embodiment, the control valve 622 is maintained in the hold state (Vh) at the time when the coating processing operation ends and shifts to the standby state. The original pressure is suppressed (decreased) from the value P in the coating process to a value P (L) that is small enough to prevent liquid column collapse. Thereby, the continuous discharge of the coating liquid from the nozzle 23 is maintained in a state where the discharge amount per unit time is suppressed as compared with the time during the coating process. That is, the standby state of the coating apparatus 1 in the present embodiment means that the opening of the control valve 622 is not controlled and is kept at the time of the coating process, while the original pressure of the pressurized tank 24 is suppressed, This means that the discharge amount of the coating liquid is suppressed while suppressing column collapse. Note that such a standby state realization method performed in the present embodiment is referred to as “main pressure suppression standby”.

  When a new application processing execution instruction is given to the coating apparatus 1 during the standby state due to the standby for suppressing the original pressure, the original pressure of the pressure tank 24 is set to the value P (L) in the standby state. To a steady state value P. During this time, the control valve 622 is still maintained in the hold state (Vh). When the original pressure value returns to P, the control valve 622 is switched to the servo state (Vs). Thereafter, as described above, the opening degree of the control valve 622 is adjusted so that the flow rate of the coating liquid supplied to the nozzle 23 becomes a target value, and when the flow rate substantially matches the target value, the control valve 622 is turned on. Switch to the hold state again and execute the coating treatment operation. That is, in the case of the present embodiment, in principle, the servo state is applied only when the flow rate of the coating liquid supplied to the nozzle 23 is adjusted prior to performing the coating process.

  On the other hand, in the case shown in FIG. 9, the control valve 622 is immediately brought into the servo state at the time when the coating processing operation is completed and the state shifts to the standby state. However, in order to suppress the discharge amount of the coating liquid in the standby state (to the extent that liquid column collapse does not occur), the target value of the coating liquid supplied to the nozzle 23 is suppressed as compared with the case where the coating process is performed. The In FIG. 9, this state is expressed as Vs (L) and is distinguished from the servo state in the case of performing the coating process. In such a case, in order to achieve the suppressed target value, the opening degree of the control valve 622 is smaller than that in the case where the application process is performed. On the other hand, the original pressure in the pressurizing tank 24 is maintained at the same value P as when the coating process is performed. Therefore, the standby state in the case shown in FIG. 9 is that the original pressure of the pressurized tank 24 is maintained, while the control valve 622 is in a servo state having a smaller opening than that in the case of performing the coating process. This means that the discharge amount of the coating liquid is suppressed while suppressing column collapse. The method for realizing the standby state in such a manner is referred to as “flow rate suppression standby”.

  If the case of this embodiment shown in FIG. 8 and the case shown in FIG. 9 are compared, both are the same in terms of aiming to suppress the collapse of the liquid column and limit the discharge in the standby state. There is a significant difference in the time required from when the execution instruction is given until the actual application processing is possible, and in the case of this embodiment, application is performed in a shorter time than in other cases. A state in which processing can be performed can be realized. Specifically, in the case of the present embodiment shown in FIG. 8, the time from the application process execution instruction to the start of the application process operation is ΔT1, and in the case shown in FIG. 9, the application process execution instruction is changed to the application process. When the time until the operation is started is ΔT2, the relationship ΔT1 <ΔT2 is established.

  In the case of this embodiment shown in FIG. 8, the opening degree of the control valve 622 is maintained as it is until the flow rate adjustment control is performed for the next coating process after the coating process is completed. Therefore, the flow rate approaches the target value even if the opening degree is not changed so much during the flow rate adjustment control, whereas in the case shown in FIG. This is because the opening degree of the valve 622 is greatly different, and it takes time to adjust the opening degree to bring the flow rate close to the target value.

  FIG. 10 is a specific example of the change in the discharge pressure at the nozzle 23 in the case of standby for suppressing the original pressure. FIG. 11 is a specific example of the change in the discharge pressure at the nozzle 23 in the case of the flow rate suppression standby shown for comparison. In any case, the standby time (the original pressure suppression time in the case of the original pressure suppression standby, the flow rate suppression time in the case of the flow rate suppression atmosphere) WT is the same.

  Both in the standby state for suppressing the original pressure shown in FIG. 10 and in the standby state for suppressing the flow rate shown in FIG. 11, the discharge pressure is within a range within ± 0.01 MPa, which is an allowable range for the operation of the apparatus. Recover up to. However, in the case of standby pressure suppression standby, as shown in FIG. 10, the discharge pressure recovers to within ± 0.002 MPa of the discharge pressure immediately before standby in 15 seconds from the end of the standby state, In the case of the flow rate suppression standby, as shown in FIG. 11, it takes about 25 seconds for the discharge pressure to recover to within a range of ± 0.002 MPa of the discharge pressure immediately before the standby.

  Although illustration is omitted, the time required for the application pressure to recover to within a range of ± 0.002 MPa is the value of the standby time WT in both cases of the standby suppression and the standby of the flow rate. It is almost the same regardless. Therefore, when the original pressure suppression standby is adopted, the discharge state of the nozzle 23 can be made substantially the same as that before the standby in about 3/5 time in the case of the flow rate suppression standby regardless of the length of the standby time. .

  In other words, the coating apparatus 1 according to the present embodiment performs the standby operation from the standby operation to the start of the coating process while reducing the discharge amount of the coating liquid in the standby state by performing the standby suppression. , Has become an excellent one. In addition, the advantage is more effective as the number of nozzles 23 provided is larger. This is because, as the number of nozzles 23 increases, the time required for flow rate adjustment in each nozzle 23 is more likely to vary in the case shown in FIG. 9 than in the case of the present embodiment. This is because the time from when the execution instruction is issued until the coating operation can be performed becomes longer.

  Preferably, P (L) /P≧0.75 in standby pressure suppression standby. In other words, if P (L) /P=0.75, the discharge of the coating liquid can be suppressed to the maximum without causing the liquid column to collapse. Although depending on the flow rate, when P (L) /P=0.75, it is possible to suppress the discharge amount by about 15% to 25% compared to the case where the original pressure is not reduced.

  FIG. 12 is a diagram illustrating the relationship between the degree of suppression of the source pressure during standby for suppressing the source pressure and the discharge behavior of the coating liquid from the nozzle. Specifically, the discharge flow rate and the standby time (source pressure suppression time) WT are constant, and the value of P (L) / P is changed to four levels of 0.75, 0.65, 0.55, and 0.45. Thus, the change in the discharge flow rate value per unit time was examined. In FIG. 12, the discharge flow rate value per unit time is standardized with a value in a steady state (a state in which the original pressure is not suppressed) being set to 1.

  As shown in FIG. 12 (a), in the case of P (L) /P=0.75, the amount of change once reduced by the suppression of the original pressure returns to the original again and becomes almost stable, but FIG. 12 (b) In all cases of P (L) / P <0.75 shown in (d), the amount of change after being lowered becomes unstable. That is, in FIG. 12, when P (L) / P <0.75, the discharge state of the coating liquid from the nozzle 23 becomes difficult to stabilize when starting a new coating processing operation, and further, the liquid column collapses. Indicates that it is not preferable because it tends to occur.

  As described above, according to the present embodiment, it is possible to realize a coating apparatus that can quickly return from the standby operation to the start of the coating process while reducing the discharge amount of the coating liquid in the standby state.

<Quantitative evaluation using experimental equipment>
Hereinafter, an outline of the experimental apparatus 1000 that can experimentally and quantitatively evaluate the change in the discharge state of the coating liquid that occurs when the discharge condition from the nozzle 23 is changed in the coating apparatus 1 according to the present embodiment. explain. FIG. 13 is a diagram schematically showing the configuration of the experimental apparatus 1000.

  The experimental apparatus 1000 is connected to a pressurized tank 1024 in which an organic solvent (hereinafter referred to as a coating solution) as a simulated coating solution is stored, a metal pipe 1241 connected to the pressurized tank 1024, and a pipe 1241. The coating liquid supply tube 1064 made of a flexible material and a 15 μm-diameter nozzle 1023 connected to the tip of the coating liquid supply tube 1064 are mainly provided. Further, a filter 1242, a mass flow controller 1062, and an electromagnetic on-off valve 1063 are provided in the middle of the pipe 1241.

  In addition, a first pressure gauge 1001 for measuring the pressure of the coating solution on the upstream side of the coating solution supply tube 1064 is provided in the middle of the pipe 1241 and in the vicinity of the connection portion with the coating solution supply tube 1064. It becomes. On the other hand, a second pressure gauge 1002 for measuring the pressure of the coating solution on the upstream side of the coating solution supply tube 1064 is provided in the middle of the coating solution supply tube 1064 and in the vicinity of the nozzle 1023. Further, an electronic balance 1003 for weighing the coating liquid discharged from the nozzle 1023 is provided below the nozzle 1023. The electronic balance 1003 can measure the weight of the coating liquid discharged from the nozzle 1023 at regular intervals. That is, the experimental apparatus 1000 is an apparatus that can quantitatively evaluate the change in the discharge weight per unit time.

  Since the experimental apparatus 1000 includes only one nozzle 1023, the experimental apparatus 1000 is different from the coating apparatus 1 including a plurality of nozzles 23. However, the discharge conditions and discharge behavior of the coating liquid from the nozzles are the same as those of the coating apparatus 1. The contents of the above are reproduced and can be fully evaluated.

  For example, FIG. 14 shows a discharge in the experimental apparatus 1000 when the nozzle that discharges the coating liquid is closed for a fixed time CT at a constant flow rate (that is, the discharge weight value per unit time of the coating liquid is constant). It is a figure which illustrates the time-dependent change of a weight value. In FIG. 14, the discharge flow rate value per unit time is standardized with a value in a steady state (a state in which the original pressure is not suppressed) being set to 1.

  In FIG. 14, in the case of the graph shown by the solid line, the weight change value returns to the same value as the initial value after the closed nozzle is opened again, whereas in the case of the graph shown by the broken line, the weight changes. A large fluctuation occurs, for example, the value becomes zero. For the former, it is judged that no liquid column collapse has occurred. About the latter, it is judged that the liquid column collapse occurred. Such a result shows that the collapse of the liquid column can occur when the nozzle is completely closed by the time CT.

  Further, the evaluation illustrated in FIGS. 10 to 12 can also be performed using the experimental apparatus 1000. That is, during the discharge of the coating liquid at a constant flow rate, the above-described evaluation can be performed by measuring the change in the discharge weight value with the electronic balance 1003 when the original pressure or the flow rate is changed for a predetermined time. It can be carried out.

DESCRIPTION OF SYMBOLS 1 Application | coating apparatus 8 Control part 10 Substrate holding | maintenance part 11 Substrate moving mechanism 12 Rail 13 Base 14 Rotating base 15 Imaging part 17, 18 Liquid receiving part 18 Liquid receiving part 20 Coating head 21 Head moving mechanism 22 Guide part 23, 1023 Nozzle 24 1024 Pressurized tanks 241a, 1241 Piping 241b Branch pipe 25 Air supply source 26 Tube group 31 Slider 32 Through hole 32h Injection hole 33 Pulley 34 Synchronous belt 61 Electropneumatic regulator 62, 1062 Mass flow controller 63, 1063 Electromagnetic switching valve 64, 1064 Coating liquid supply tube 100 Substrate 100s Application target surface 621 Mass flow meter 622 Control valve 623 Valve control unit 1000 Experimental apparatus 1002 Second pressure gauge 1003 Electronic balance

Claims (5)

A coating apparatus for applying a coating liquid to a substrate,
A holding unit for holding the substrate;
A nozzle for discharging the coating liquid;
A nozzle moving mechanism for moving the nozzle;
A reservoir for storing the coating liquid;
A coating liquid supply section for supplying the coating liquid to the nozzle through a coating liquid flow path by applying pressure to the coating liquid stored in the storage section;
With
In applying the coating liquid to the substrate, after controlling the opening of the coating liquid channel so that the flow rate of the coating liquid substantially matches a predetermined target value, the opening of the coating liquid channel is kept constant. The nozzle is moved above the substrate while continuously discharging the coating liquid from the nozzle in a maintained state,
At the time of waiting until a new application is performed after the application of the application liquid, the application liquid from the nozzle is maintained with the opening of the application liquid flow path being kept the same as that during the application of the application liquid. The pressure applied to the coating liquid in the coating liquid supply unit while maintaining a continuous discharge state of
In the new application, after the pressure applied to the application liquid in the application liquid supply unit is returned to the same as that during the application, the application liquid is again set so that the flow rate of the application liquid substantially matches a predetermined target value. Performed after controlling the opening of the flow path,
An applicator characterized by that. The coating apparatus according to claim 1,
A flow rate measuring unit for measuring the flow rate of the coating liquid flowing through the coating liquid flow path;
An opening degree defining part for regulating the opening degree of the coating liquid flow path;
An opening degree control unit for controlling the opening degree of the coating liquid channel in the opening degree defining unit based on the measurement result of the flow rate of the coating liquid in the flow rate measurement unit;
With
The coating liquid is applied to the substrate after the opening degree control unit controls the opening degree of the coating liquid channel in the opening degree defining unit so that the flow rate of the coating liquid substantially matches a predetermined target value. The control of the opening degree defining unit by the opening degree control unit is stopped and the coating liquid is continuously discharged from the nozzle while the opening degree of the coating liquid channel is kept constant. By moving the nozzle in
After waiting for a new application after the application of the application liquid, the opening degree of the application liquid channel is controlled by stopping control of the opening degree defining unit by the opening degree control unit. While maintaining the same as the time of application of the liquid, while maintaining the continuous discharge state of the application liquid from the nozzle, suppress the pressure applied to the application liquid in the application liquid supply unit than during the application,
In the new application, after the pressure applied to the application liquid in the application liquid supply unit is returned to the same as that during the application, the opening degree is again set so that the flow rate of the application liquid substantially coincides with a predetermined target value. The control unit performs after controlling the opening degree of the coating liquid channel in the opening degree defining part,
An applicator characterized by that. The coating apparatus according to claim 1 or 2,
During the standby, the pressure applied to the coating liquid in the coating liquid supply unit is suppressed to a range of 0.75 times or more that during coating,
An applicator characterized by that. A coating apparatus according to any one of claims 1 to 3,
A coating liquid supply tube connected to the nozzle and deformed following the movement of the nozzle by the nozzle moving mechanism;
With
The coating liquid supply tube constitutes a part of the coating liquid flow path;
An applicator characterized by that. An operation method of a coating apparatus that applies a coating liquid onto a substrate by discharging a coating liquid from the nozzle while moving the nozzle,
The supply of the coating liquid to the nozzle is performed by applying pressure to the coating liquid stored in a storage unit connected to the nozzle through a coating liquid flow path,
In applying the coating liquid to the substrate, after controlling the opening of the coating liquid channel so that the flow rate of the coating liquid substantially matches a predetermined target value, the opening of the coating liquid channel is kept constant. The nozzle is moved above the substrate while continuously discharging the coating liquid from the nozzle in a maintained state,
At the time of waiting until a new application is performed after the application of the application liquid, the application liquid from the nozzle is maintained with the opening of the application liquid flow path being kept the same as that during the application of the application liquid. The pressure applied to the coating liquid in the coating liquid supply unit while maintaining a continuous discharge state of
In the new application, after the pressure applied to the application liquid in the application liquid supply unit is returned to the same as that during the application, the application liquid is again set so that the flow rate of the application liquid substantially matches a predetermined target value. Performed after controlling the opening of the flow path,
A method for operating the coating apparatus.

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