WO2013121814A1

WO2013121814A1 - Coating device

Info

Publication number: WO2013121814A1
Application number: PCT/JP2013/050609
Authority: WO
Inventors: 展雄堀内; 学釜谷
Original assignee: 東レエンジニアリング株式会社
Priority date: 2012-02-17
Filing date: 2013-01-16
Publication date: 2013-08-22
Also published as: JP2013166134A; TW201338868A

Abstract

The present invention is a coating device provided with a stage on which a substrate is placed, and a mouthpiece (34) having a slit nozzle (34a) for discharging a coating liquid, a coating film being formed on the substrate by relative movement of the mouthpiece (34) and the stage, wherein a coating liquid supply hole (42) and a plurality of air vent holes (44, 43R, 43L) are provided to the mouthpiece (34), the air vent holes (44, 43R, 43L) and a waste tank (60) are linked together by waste pipes (52, 53, 54), at least two air vent holes (44, 43R, 43L) of the plurality of air vent holes (44, 43R, 43L) are connected to a shared waste tank (60), and the piping diameter and piping length of all of the waste pipes (52, 53, 54) are adjusted so that any pressure loss occurring among the waste pipes (52, 53, 54) is equal. This configuration makes it possible to minimize the time and amount of coating liquid needed for an air vent treatment.

Description

Coating device

The present invention relates to a coating apparatus that coats a coating solution on a substrate, and more particularly to an air vent mechanism that discharges air present in a die.

In a flat panel display such as a liquid crystal display or a plasma display, a substrate made of glass or the like coated with a resist solution (referred to as a coated substrate) is used. The coated substrate is formed by a coating apparatus that uniformly coats a resist solution (hereinafter referred to as a coating solution) (see Patent Document 1 below). That is, the coating apparatus includes a stage on which the substrate is placed and a coating unit having a base part that discharges the coating liquid. While discharging the coating liquid from the slit nozzle of the base part, the substrate and the coating unit By performing a coating operation that relatively moves the coating film, a coating film having a predetermined thickness is formed on the substrate.

Generally, an air vent process is performed before such a coating operation. That is, the base portion is provided with an internal flow path for temporarily storing the coating liquid supplied by a pump or the like, and the coating operation is performed in a state where air such as bubbles or air pockets is mixed in the internal flow path. If it does, it will become easy to produce fluctuation | variation in the pressure which discharges a coating liquid, and will become a factor of a coating nonuniformity. Therefore, the air vent process is performed to discharge the air present in the internal flow path, so that the coating liquid is stably ejected from the slit nozzle and the occurrence of coating unevenness is suppressed.

Specifically, as shown in FIG. 6, the base part 100 is provided with a plurality of air vent holes 103 for discharging the air in the internal flow path 102 in addition to the coating liquid supply hole 101 to which the coating liquid is supplied. . A waste liquid tank 104 is provided for each of the air vent holes 103, and the air vent hole 103 and the waste liquid tank 104 are connected one-to-one through a waste liquid pipe 105. In the air vent process, the coating liquid is supplied from the coating liquid supply hole 101, whereby the air present in the internal flow path 102 of the base part 100 is discharged from the slit nozzle 106 and the air vent hole 103 together with the coating liquid. Then, by continuing to supply the coating liquid from the coating liquid supply hole 101, all the air in the internal flow path 102 is discharged and the internal flow path 102 is filled with the coating liquid. After the air vent process is completed, a coating operation is performed, whereby a stable coating film is formed on the substrate.

Here, the waste liquid pipes 105 that connect the air vent holes 103 and the waste liquid tanks 104 have the same diameter so that the pressure loss generated in the respective waste liquid pipes 105 is almost equal. The piping length to the waste liquid tank 104 is set equal. Thereby, the pressure loss of each waste liquid pipe 105 becomes substantially equal, and the air in the internal flow path 102 is evenly pushed out to each air vent hole 103 by the supplied coating liquid. That is, because the pressure loss between the slit nozzle 106 and the waste liquid pipe 105 is different, a large amount of coating liquid is discharged from the air vent hole 103 of the waste liquid pipe 105 with a small pressure loss, and exists near the air vent hole 103 of the waste liquid pipe 105 with a large pressure loss. The problem of wasteful consumption of the coating liquid supplied to push out the air that does not discharge the air is suppressed.

JP 2006-281091 A

However, the above-described coating apparatus has a problem that the apparatus cost becomes high. That is, the waste liquid tank 104 is expensive because it is necessary to attach a liquid level sensor or the like for determining whether or not the waste liquid is full. And in the said coating device, since such a waste liquid tank 104 is provided independently with respect to each air vent hole 103, there exists a problem that it is difficult to hold down apparatus cost.

Here, if the waste liquid pipes 105 connected to the respective air vent holes 103 are directly connected to the common waste liquid tank 104, the distance to the waste liquid tank 104 changes as a result of the positions of the respective air vent holes 103 being different. The pressure loss of each of the 105 changes, and there is a problem that an extra coating solution is required to discharge the air in the internal flow path 102 in the air vent process, and the time required for the air vent process is also required.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a coating apparatus capable of suppressing the cost of the apparatus while suppressing the amount and time of the coating liquid necessary for the air vent process.

In order to solve the above problems, a coating apparatus of the present invention includes a stage on which a substrate is placed, and an internal channel that stores a coating solution, and a slit nozzle that discharges the coating solution stored in the internal channel. A coating device for forming a coating film on a substrate by relatively moving the nozzle portion and the stage, and the coating portion is provided with a coating liquid in an internal flow path. A coating liquid supply hole to be supplied and a plurality of air vent holes for discharging air existing in the internal flow path by supplying the coating liquid from the coating liquid supply hole are provided, and the air vent hole and the waste liquid tank are disposed of as waste liquid. Connected by piping, at least two of the air vent holes are connected to a common waste liquid tank, and all the waste liquid pipes have the same pressure loss generated in each waste liquid pipe. Pipe diameter and the pipe length is characterized by being adjusted so.

According to the coating apparatus, since the waste liquid pipe connected to at least two air vent holes is connected to a common waste liquid tank, the waste liquid tank is installed as compared with the conventional case where the waste liquid tank is provided in each air vent hole. The number of devices can be reduced, and the cost of the apparatus can be reduced. In addition, by adjusting the pipe diameter and pipe length of the waste liquid pipe connected to the common waste liquid tank, the pressure loss generated in all the waste liquid pipes is set to be approximately equal. In addition, the ease of exhausting air such as bubbles can be made substantially equal. That is, the amount of the coating liquid necessary for the air vent process is not substantially different from the amount of the coating liquid that has been conventionally required, and the time required for the air vent process is also not substantially different from the conventional one. Therefore, the apparatus cost can be suppressed while suppressing the amount and time of the coating liquid necessary for the air vent process.

Further, as a specific aspect, the base portion has a shape in which the direction orthogonal to the moving direction is the longitudinal direction, and the air vent hole is provided at one end in the longitudinal direction of the base portion. The waste liquid pipes connected to the air vent holes can be connected to a common waste liquid tank.

Further, the total pressure loss generated in all the waste pipes with the waste liquid valve opened may be set to be smaller than the pressure loss generated in the slit nozzle as long as air is not sucked from the slit nozzle. .

According to this configuration, since the coating liquid existing in the internal flow path of the base part is easily discharged from the waste liquid piping, the pressure loss value generated in the slit nozzle from the total value of the pressure loss generated in all waste liquid piping. The larger the is, the more the amount of coating solution discharged to waste can be suppressed. That is, since air in the internal flow path often exists in the upper part of the internal flow path, the amount of air mixed in the coating liquid discharged from the slit nozzle that opens downward is small. Therefore, the amount of the coating liquid used for the air vent process can be suppressed by suppressing the coating liquid discharged from the slit nozzle.

According to the coating apparatus of the present invention, the apparatus cost can be suppressed while suppressing the amount and time of the coating liquid required for the air vent treatment.

It is a perspective view which shows the coating device which concerns on embodiment of this invention. It is the schematic which shows the leg part vicinity of an application unit. It is a figure which shows a nozzle | cap | die part and a waste liquid tank roughly. It is a figure which shows the internal flow path of a nozzle | cap | die part. It is a figure which shows the flow of air at the time of performing an air vent process, (a) is a figure which shows the case where the pressure loss of a waste liquid piping is equal, (b) is the case where the pressure loss of a waste liquid piping is different. FIG. It is a figure which shows the periphery of the waste liquid of a nozzle | cap | die part in the conventional coating device.

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

FIG. 1 is a perspective view schematically showing a coating apparatus according to an embodiment of the present invention, FIG. 2 is a view showing the vicinity of a leg portion of a coating unit, and FIG. 3 is a view showing a base part and a waste liquid tank. FIG. 4 schematically shows the internal flow path of the base part.

As shown in FIGS. 1 to 4, the coating apparatus forms a coating film of a liquid material (hereinafter referred to as a coating solution) such as a chemical solution or a resist solution on a substrate 10, and includes a base 2 and a substrate. 10, and a coating unit 30 configured to be movable in a specific direction with respect to the stage 21.

In the following description, the direction in which the coating unit 30 moves is described as the X-axis direction, the direction orthogonal to this in the horizontal plane is defined as the Y-axis direction, and the direction orthogonal to both the X-axis and Y-axis directions is described as the Z-axis direction. To proceed.

The stage 2 is arranged at the center of the base 2. The stage 21 is for placing the substrate 10 that has been carried in. The stage 21 is provided with a substrate holding means, and the substrate 10 is held by the substrate holding means. Specifically, a plurality of suction holes formed on the surface of the stage 21 are formed, and by generating a suction force in the suction holes, the substrate 10 can be adsorbed and held on the surface of the stage 21. ing.

Further, the stage 21 is provided with a substrate lifting mechanism for moving the substrate 10 up and down. Specifically, a plurality of pin holes are formed on the surface of the stage 21, and lift pins (not shown) that can be moved up and down in the Z-axis direction are embedded in the pin holes. That is, when the substrate 10 is carried in with the lift pins protruding from the surface of the stage 21, the tip portion of the lift pins can contact the substrate 10 and hold the substrate 10. The substrate 10 can be placed on the surface of the stage 21 by lowering the lift pins from the state and accommodating them in the pin holes.

Further, the coating unit 30 is for discharging a coating solution onto the substrate 10 to form a coating film. As shown in FIGS. 1 and 2, the coating unit 30 includes a leg portion 31 connected to the base 2 and a base portion 34 extending in the Y-axis direction. It is attached so as to be movable in the X-axis direction in a state of straddling. Specifically, rails 22 extending in the X-axis direction are installed at both ends of the base 2 in the Y-axis direction, and leg portions 31 are slidably attached to the rails 22. A linear motor 33 is attached to the leg portion 31, and by driving and controlling the linear motor 33, the coating unit 30 moves in the X-axis direction and can be stopped at an arbitrary position.

Further, as shown in FIG. 2, a base part 34 for applying the coating liquid is attached to the leg part 31 of the coating unit 30. Specifically, the leg portion 31 is provided with a rail 37 extending in the Z-axis direction and a slider 35 that slides along the rail 37, and the slider 35 and the base portion 34 are connected to each other. . A ball screw mechanism driven by a servomotor is attached to the slider 35. By controlling the drive of the servomotor, the slider 35 moves in the Z-axis direction and can be stopped at an arbitrary position. It has become. That is, the base part 34 is supported so as to be able to contact and separate from the substrate 10 held on the stage 21.

The base part 34 is for discharging a coating liquid to form a coating film on the substrate 10. The base part 34 is a columnar member having a shape extending in one direction, and is provided so as to be substantially orthogonal to the traveling direction of the coating unit 30. A slit nozzle 34a extending in the longitudinal direction is formed in the base part 34, and the coating liquid supplied to the base part 34 is uniformly ejected from the slit nozzle 34a in the longitudinal direction. . Therefore, by running the coating unit 30 in the X-axis direction with the coating liquid being discharged from the slit nozzle 34a, a coating film having a constant thickness is formed on the substrate 10 over the longitudinal direction of the slit nozzle 34a. It has become so. In this embodiment, the operation of moving the coating unit 30 in a state where the coating liquid is discharged from the slit nozzle 34a in order to apply the coating liquid is referred to as a coating operation.

As shown in FIGS. 3 and 4, the base 34 includes an internal channel 41 that stores the coating solution, a coating solution supply hole 42 that supplies the coating solution to the internal channel 41, and an internal channel 41. And an air vent hole 43 for discharging air such as air bubbles and air pockets. Here, when the air vent hole 43 is specifically referred to as an air vent hole 43L, and the air vent hole 43 on the right side is particularly referred to as an air vent hole 43R. 43.

The internal flow path 41 is a part for temporarily storing the supplied coating liquid, and in the present embodiment, the internal flow path 41 is formed in the base part 34 along the longitudinal direction. Specifically, it has a shape extending along the longitudinal direction of the base part 34, and is highest at the central part 41a corresponding to the central part 41a in the longitudinal direction and lower at the side end parts 41b at both end parts in the longitudinal direction. The lower part is formed and communicated with the slit nozzle 34a. A top portion of the central portion 41 a communicates with the air vent hole 44, and a coating liquid supply hole 42 communicates with a lower portion of the air vent hole 44. The coating liquid supply hole 42 is connected to a pump 51 that supplies the coating liquid by a supply pipe 55. When the coating liquid is supplied by operating the pump 51, the coating liquid is supplied from the coating liquid supply hole 42 to the internal flow path 41. To be supplied. The air α in the internal flow path 41 and the air α in the supplied coating solution gather at the central portion 41 a by buoyancy and are discharged through the air vent hole 44.

The air vent hole 44 is connected to an air vent pipe 52, and the air vent pipe 52 is connected to a waste liquid tank 60. That is, the air α (including the coating liquid in which the air α is mixed) in the internal flow path 41 passes through the air vent hole 52 through the air vent hole 44 and is discharged to the waste liquid tank 60. This piping is provided with an air vent valve 52a. The application operation is performed with the air vent valve 52a closed, so that the supplied application liquid does not leak through the air vent hole 44 during the application operation.

The waste liquid tank 60 stores air α in the internal flow path 41 and air α mixed as bubbles in the coating liquid. In this embodiment, only one waste liquid tank 60 is provided in the coating device, and is provided in the leg portion 31 of the coating unit 30 (see FIG. 2). The waste liquid tank 60 is connected to an air vent pipe 52 connected to the cap portion 34 and a waste liquid pipe 53 described later, and the coating liquid containing air α and air α discharged from the internal flow path 41 is a waste liquid tank. 60 can be stored. In addition, a liquid level sensor (not shown) is attached to the waste liquid tank 60 to detect that the waste liquid is full, and from the waste liquid tank 60 by a waste liquid pump (not shown) installed outside the apparatus. Waste liquid is discharged to the outside of the device. In addition, since the waste liquid tank 60 is attached to the leg part 31, even if the coating unit 30 moves, the distance of the nozzle | cap | die part 34 and the waste liquid tank 60 does not change. Accordingly, the air vent pipe 52 and the waste liquid pipe 53 connected to the waste liquid tank 60 are kept at a certain length.

The air vent holes 43 are for discharging the air α in the internal flow path 41 in the air vent process, and two air vent holes 43 are provided at both ends in the longitudinal direction of the base part 34. Here, the air vent process is a process for removing the air α in the internal flow path 41 so that the air α is not discharged from the slit nozzle 34 a onto the substrate 10, and usually before the coating operation is performed. Done. Specifically, the cleaning is performed by supplying the coating liquid from the coating liquid supply hole 42 after cleaning the internal flow path 41 or replacing the base part 34 with a new base part 34. That is, by supplying the coating liquid from the coating liquid supply hole 42, the air α in the internal flow path 41 is pushed out from the slit nozzle 34a, the air vent hole 44, and the air vent hole 43, thereby discharging the air α from the internal flow path 41. To do.

The air vent hole 43 is formed to communicate with the internal flow path 41 and is connected to the waste liquid pipe 53. Thus, during the air vent process, the air α and the coating liquid containing the air α in the internal flow path 41 are discharged from the air vent hole 43 to the waste liquid tank 60 through the waste liquid pipe 53. These waste liquid pipes 53 are connected to a common waste liquid tank 60, and the air α and the coating liquid containing air α discharged from any of the air vent holes 43 are discharged to the waste liquid tank 60. The waste liquid pipe 53 includes a parallel portion 531 extending along the base portion 34 and a vertical portion 532 orthogonal to the parallel portion 531. In other words, a joint 54 that changes the direction by 90 degrees is connected to the parallel part 531 opposite to the side connected to the air vent hole 43, and a vertical part 532 connected to the joint 54 is connected to the waste liquid tank 60. ing. As a result, the air α and the coating liquid containing the air α exiting the air vent hole 43 are discharged to the waste liquid tank 60 via the parallel portion 531 and the vertical portion 532.

Further, the waste liquid pipe 53 is set so that the pressure loss generated in the waste liquid pipe 53 becomes equal. Specifically, the pressure loss is set by adjusting the pipe diameter and pipe length of the waste liquid pipe 53. That is, as shown in FIG. 3, the waste liquid pipe 53 has a parallel portion 531 having the same diameter (in FIG. 3, the thickness of the line indicating the waste liquid pipe 53 indicates the pipe inner diameter). . Since the waste liquid tank 60 is installed near the air vent hole 43R, the parallel portion 531 of the waste liquid pipe 53 is shorter when connected to the air vent hole 43R than when connected to the air vent hole 43L. Therefore, when only this parallel part 531 is compared, the pressure loss is larger in the air vent hole 43L. On the other hand, when comparing the vertical portion 532, the waste liquid pipe 53 connected to the air vent hole 43R is formed to have a smaller diameter than the waste liquid pipe 53 connected to the air vent hole 43L. That is, the pressure loss of the vertical portion 532 is set so that the waste liquid pipe 53 connected to the air vent hole 43R is larger. That is, since the length of the waste liquid pipe 53 connected to the air vent hole 43 is different by using the waste liquid tank 60 in common, the pressure loss generated in the entire waste liquid pipe 53 by forming a part of the waste liquid pipe 53 to have a small diameter. Is set to be equal in any waste liquid piping 53. In this embodiment, the parallel portion 531 of the waste liquid pipe 53 connected to the air vent hole 43 uses the same diameter pipe, and the pressure loss is adjusted by using the waste liquid pipe 53 having a different diameter only in the vertical portion 532. In this way, by making the parallel part 531 of the waste liquid pipe 53 directly connected to the air vent hole 43 the same diameter, the manufacturing cost of the base part 34 can be reduced, and it is more pressure to change the diameter of the vertical part 532. Easy to adjust loss. It should be noted that setting the pressure loss equal is not limited to the case where the pressure losses are set to be completely the same, but it is sufficient if the air α is smoothly discharged from any of the air vent holes 43 so that the degree of discharge is the same. .

Further, in the present embodiment, the total value of the pressure loss generated in all the waste liquid pipes 53 is set to be smaller than the pressure loss generated in the slit nozzle 34a in a range where the air α is not sucked from the slit nozzle 34a. Yes. Thereby, at the time of an air vent process, the quantity by which the supplied coating liquid is discharged | emitted from the slit nozzle 34a to waste can be suppressed. That is, when the coating liquid is supplied from the coating liquid supply hole 42 during the air vent process, the air α existing in the internal channel 41 is discharged from the slit nozzle 34 a, the air α vent hole, and the air vent hole 43, and is supplied to the internal channel 41. When the coating liquid is stored, the air α rises due to buoyancy, and the coating liquid containing the air α and the air α is discharged from the air α vent hole and the air vent hole 43. In this state, the smaller the pressure loss value generated in the slit nozzle 34a than the total pressure loss value generated in all the waste liquid pipes 53, the easier it is to discharge from the slit nozzle 34a than to discharge from the air vent hole 43. However, since the air α has risen due to buoyancy, a large amount of the coating liquid not mixed with the air α is discharged from the slit nozzle 34a that is easily discharged. Therefore, by setting the total value of the pressure loss generated in the waste liquid pipe 53 to be smaller than the pressure loss generated in the slit nozzle 34a in a range where the air α is not sucked from the slit nozzle 34a, it is difficult to discharge from the slit nozzle 34a. Even if the air α rises due to buoyancy, the discharge from the slit nozzle 34a is suppressed, and it is possible to prevent the coating liquid from being wasted.

Further, the suction of the air α from the slit nozzle 34a here means that the total value of the pressure loss of all the waste liquid pipes 53 in which a later-described waste liquid valve 53a is opened is significantly smaller than the pressure loss generated in the slit nozzle 34a. In this case, the air α is sucked from the slit nozzle 34a and the liquid flows into the waste liquid pipe 53. Normally, the coating liquid supplied from the coating liquid supply hole 42 is separated from the slit nozzle 34a and the waste liquid pipe by the ratio of pressure loss. In this case, more liquid flows to the waste liquid pipe 53 than the coating liquid supplied from the coating liquid supply hole 42. That is, the range in which the air α is not sucked from the slit nozzle 34a means that the coating liquid supplied from the coating liquid supply hole 42 does not suck the air α from the slit nozzle 34a to the maximum extent to the waste liquid pipe 53. A state in which the coating liquid containing α is discharged.

The waste liquid pipe 53 is provided with a waste liquid valve 53a. During the application operation, the waste liquid valve 53a is closed, so that the supplied application liquid does not leak through the air vent hole 43 during the application operation.

With such a configuration, the air α in the internal flow path 41 can be smoothly discharged in the air vent process. That is, when the coating liquid is supplied from the coating liquid supply hole 42, the internal flow path 41 is filled with the coating liquid, and the already existing air reservoir is pushed out from the slit nozzle 34a, the air vent hole 44, and the air vent hole 43. It is discharged by. At this time, not only the air α but also the coating liquid containing the air α is simultaneously discharged from the slit nozzle 34a, the air vent hole 44, and the air vent hole 43. Then, when the internal flow path 41 is almost filled with the coating liquid, the air pool is almost eliminated, but air α such as bubbles is present in the filled coating liquid, so the coating liquid supply hole 42. By continuing to supply the coating liquid from, the remaining bubbles are pushed out and discharged. That is, the remaining air α rises due to buoyancy and is mainly discharged from the air vent hole 44, but the air α that does not move to the air vent hole 44 is pushed out from the air vent hole 43 by the supply pressure of the coating liquid. Discharged. In the present embodiment, since the pressure loss of each waste liquid pipe 53 connected to the air vent hole 43 is set to be approximately equal, the application supplied from the application liquid supply hole 42 as shown in FIG. The supply pressure of the liquid is transmitted in the direction from the air vent hole 43 to the waste liquid pipe 53, and the air α that cannot be discharged from the air vent hole 44 is discharged to the waste liquid tank 60 through the air vent hole 43. In FIG. 5, solid arrows indicate the flow of the coating liquid, and broken arrows indicate the flow of the air α.

If the pressure loss of one waste liquid pipe 53 is larger than that of the other waste liquid pipe 53, for example, as shown in FIG. 5B, the pressure loss of the waste liquid pipe 53 connected to the air vent hole 43L. Is large, it is difficult for the coating liquid to flow into the waste liquid pipe 53 having a large pressure loss, so that the supply pressure of the coating liquid is difficult to be transmitted and the air in the vicinity of the air vent hole 43L to which the waste liquid pipe 53 having a large pressure loss is connected. α stays at that position and is not discharged.

On the other hand, the total value of the pressure loss of all the waste liquid pipes 53 is set to be smaller than the pressure loss of the slit nozzle 34a in a range where the air α is not sucked from the slit nozzle 34a. The amount can be reduced. That is, when the internal flow path 41 is filled with the coating liquid by performing the air vent process, the air α rises and the remaining air α is reduced in the vicinity of the slit nozzle 34a, so that the coating liquid discharged from the slit nozzle 34a is reduced. Almost does not contain air, and the coating solution is discharged as it is. Therefore, the total value of the pressure loss of all the waste liquid pipes 53 is set to be smaller than the pressure loss of the slit nozzle 34a in a range in which the air α is not sucked from the slit nozzle 34a. And the coating liquid containing air α easily flows from the waste liquid pipe 53, and the amount of the coating liquid containing air α discharged from all the waste liquid pipes 53 is the amount of the coating liquid containing air α discharged through the slit nozzle 34a. Therefore, the coating liquid containing air is positively discharged through the waste liquid pipe 53. Therefore, the amount of the coating liquid discharged from the slit nozzle 34a to the waste (amount of the coating liquid not including the air α) can be suppressed, and the amount of the coating liquid used for the air vent process can be suppressed.

According to the coating apparatus in the above embodiment, since the waste liquid piping 53 connected to the two air vent holes 43 is connected to one common waste liquid tank 60, the waste liquid tank 60 is provided in each of the air vent holes 43 as in the prior art. The number of necessary waste liquid tanks 60 can be reduced as compared with the case where the cost is reduced. Further, by adjusting the pipe diameter and the pipe length of the waste liquid pipe 53 connected to the common waste liquid tank 60, the pressure loss generated in all the waste liquid pipes 53 is set to be approximately equal. In this case, the ease of exhausting air α such as bubbles can be made substantially equal. That is, the amount of the coating liquid necessary for the air vent process is not substantially different from the amount of the coating liquid that has been conventionally required, and the time required for the air vent process is also not substantially different from the conventional one. Therefore, the apparatus cost can be suppressed while suppressing the amount and time of the coating liquid necessary for the air vent process.

In the above embodiment, an example in which there are two air vent holes 43 has been described, but three or more air vent holes 43 may be provided. In this case, the number of the waste liquid tanks 60 may be two or one, and all of the waste liquid tanks 60 are adjusted by adjusting the pipe diameter and the pipe length of the waste liquid pipes 53 connected to the respective air vent holes 43. The pressure loss generated in the waste liquid piping 53 may be set to be substantially equal.

Moreover, although the said embodiment demonstrated the example in which the total value of the pressure loss produced in all the waste liquid piping 53 was set smaller than the pressure loss produced in the said slit nozzle, all the waste liquid piping 53 and air vent hole were demonstrated. 44 may be set to be smaller than the pressure loss generated in the slit nozzle as long as the total value of the pressure loss generated in 44 does not suck the air α from the slit nozzle 34a. With this configuration, it is possible to further suppress the amount of application liquid discarded in the slit nozzle 34a.

DESCRIPTION OF SYMBOLS 10 Board | substrate 21 Stage 30 Application | coating unit 34 Base part 34a Slit nozzle 41 Internal flow path 42 Coating liquid supply hole 43 Air vent hole 44 Air vent hole 53 Waste liquid piping 60 Waste liquid tank

Claims

A stage on which a substrate is placed;
A base having an internal flow path for storing the coating liquid and a slit nozzle for discharging the coating liquid stored in the internal flow path;
A coating apparatus for forming a coating film on a substrate by relatively moving the base portion and the stage,
The base part has a coating liquid supply hole for supplying a coating liquid to the internal flow path, and a plurality of air vent holes for discharging air existing in the internal flow path by supplying the coating liquid from the coating liquid supply hole. Is provided,
The air vent hole and the waste liquid tank are connected by a waste liquid pipe, and at least two of the plurality of air vent holes are connected to a common waste liquid tank, and all the waste liquid pipes are generated in the respective waste liquid pipes. A coating apparatus, wherein a pipe diameter and a pipe length are adjusted so that pressure losses are equal.
The base part has a shape in which the direction orthogonal to the moving direction is the longitudinal direction, and the air vent holes are provided at one end in the longitudinal direction of the base part and are connected to the air vent holes. The coating apparatus according to claim 1, wherein the waste liquid pipe is connected to a common waste liquid tank.
The total value of the pressure loss generated in all the waste pipes in which the waste liquid valve is opened is set to be smaller than the pressure loss generated in the slit nozzle as long as air is not sucked from the slit nozzle. The coating apparatus according to 1 or 2.