JPH11319678A - Fluid application device and fluid application method - Google Patents

Abstract

(57) [Problem] To provide a fluid application device in which the start of application does not fluctuate in a constant cycle or a streaking state does not occur, and a defect of a manufactured part does not occur due to slight application unevenness. I do. A coating device main body and a rotary table device are provided.
And a coating liquid supply device 50. The coating liquid supply device 50 removes the coating fluid stored in the coating liquid tank 200 by the regulator 300 to the bubble removing device 100.
After the dissolved gas in the application fluid is removed by the bubble removing device 100, the application fluid is caused to flow out from the slit-shaped opening and supplied to the application head 10 that applies the application fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid coating apparatus for forming a substantially uniform coating film having a predetermined thickness by applying a coating fluid on an effective coating surface of a coating target member having at least a coating target portion formed in a flat plate shape. And methods.

[0002]

2. Description of the Related Art In a manufacturing process of a liquid crystal display (LCD), a semiconductor optical element, a semiconductor element, a semiconductor integrated circuit, a printed wiring board, and the like, various coating liquids such as a photoresist, an insulating material, and a solder resist are applied to a coating object ( For example, it is necessary to apply it to the surface of a glass substrate, a semiconductor wafer or the like) to form a very thin coating film of about several microns.

For example, in a manufacturing process of a liquid crystal display, a thickness of a glass substrate when dried is about 1-3.
It is necessary to coat a micron uniform photoresist.

In these cases, it is necessary to form a coating film having an extremely uniform thickness, and it is necessary to control the film thickness with high precision. We have developed a fluid coating device (slot type mucus ejection coating device) equipped with a coating head that has
Japanese Patent Application No. 5-154409, registered utility model 30048
No. 24).

This apparatus comprises, for example, a slot-type coating head and a horizontal transfer table device for sucking and transferring an object to be coated such as a glass plate. The application liquid is applied to the surface of the application object by the application head.

[0006] In order to form a uniform coating film on the surface of a coating object having an irregular shape such as a disk shape, the coating head 10 is provided with a narrow slot 2 having a width W as shown in FIG.
6, the coating liquid is formed into a thin film shape and discharged, and the slot 26 is arranged so as to face the coating object 3 in the radial direction.

First, the application object 3 is rotated by rotating the table plate 4 at a low speed, and the application liquid 6 flowing out of the application head 10 is applied to the surface of the application object 3. Next, a method of rotating the application object 3 at a high speed by the rotary table device 2 as needed to level the application liquid 6 on the surface of the application object 3 has been adopted.

Reference numeral 7 denotes a cover provided so as to cover the table plate 4 to prevent a part of the leveled coating liquid from scattering to other parts.

[0009]

However, in the conventional slot type fluid application device, the start of application fluctuates at regular intervals, causing a streaking state. Bad things were happening.

It is therefore an object of the present invention to solve the above-mentioned problems and to provide a highly reliable fluid coating apparatus which does not cause a streaking phenomenon or the like in a coating liquid.

[0011]

As one means for achieving the above object, the following arrangement is provided.

A fluid coating apparatus for applying a coating fluid on a coating effective surface of a coating target member having at least a coating target portion formed in a flat plate to form a substantially uniform coating film having a predetermined thickness. A coating head which has an opening in a shape of an arrow and applies the coating fluid by flowing out the coating fluid from the opening; and coating the coating target member by scanning the coating head on a coating effective surface of the coating target member. Coating head scanning means for applying a coating fluid on the effective surface; gas removing means for removing gas mixed in the coating fluid supplied to the coating head; and the gas provided between the gas removing means and the coating head. A supply control unit that controls supply of the application fluid supplied from the removal unit to the application head.

[0013] For example, the application target portion is a liquid crystal display substrate, and the application fluid is a coating fluid such as a photoresist, an insulating material, or a solder resist, which is applied to the substrate in a manufacturing process of the liquid crystal display substrate. The gas removing means passes the coating fluid through a passage having a gas permeable membrane disposed therearound, and maintains the outside of the gas permeable membrane in a negative pressure state so that the coating fluid in the coating fluid passes through the gas permeable membrane. It is characterized by including exhaust means for removing gas.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The inventor of the present application has found that the start of application described above varies at regular intervals, and pursues the cause of the occurrence of a streaking state. At the time of ejection, it was determined that it was likely due to volumetric expansion due to the release of pressure.

Therefore, by providing a mechanism for almost completely removing gas (dissolved gas) mixed in the coating liquid, which will be described in detail below, the above-mentioned disadvantages could be eliminated.

FIG. 1 is a partially cut-away schematic front view showing a fluid application apparatus according to an embodiment of the present invention. The fluid application device according to the present embodiment includes an application device body 1, a rotary table device 2, and an application head 1 of the application device 1.
The apparatus comprises a coating liquid supply device 50 for supplying a coating liquid to the substrate.

The rotary table device 2 includes a table plate 4 for sucking and holding the object 3 to be coated and a drive unit 5 for rotating the table plate 4. To prevent the coating liquid 6 from scattering.
Is provided to surround the table plate 4. Further, the rotation speed of the table plate 4 is detected by the detector 8, and the controller 9
The drive unit 5 is feedback-controlled so that the rotation speed of the table plate 4 becomes constant based on the value of the rotation speed detected in (1).

In the coating apparatus main body 1, a coating head 10
The arm 11 is provided at the tip of the arm 11, and the arm 11 is held by the support unit 12 so as to be able to move up and down. As shown in FIG. 4 described above, the coating head 10 is disposed so as to face in the radial direction of, for example, a disk-shaped coating target 3 that is positioned and held on the table plate 4. Are positioned so that one end of the object 3 faces the center P of the application target 3.

The coating liquid supply device 50 includes a gas removing device 100 for removing gas from the coating liquid supplied to the coating head 10, a coating liquid tank 200 for holding the coating liquid, and pressurizing gas into the coating liquid tank 200. Coating liquid tank 20
A regulator 300 is provided to derive the coating liquid from the nozzle 0 and feed the coating liquid to the coating head via the gas removing device 100.

In the above description, the example in which the object to be coated is a disk is described. However, the present invention is not limited to the above example. By controlling to move in the horizontal direction,
The object to be applied may be rectangular or square. In this case, the coating head control method described later can be applied as it is. FIG. 5 shows an example in which the application target is rectangular.

FIG. 2 is an exploded perspective view of the coating head 10, and FIG. 3 is a sectional view of the coating head 10.

The coating head 10 of this embodiment is shown in FIG.
As shown in FIG. 3, it is composed of two divided heads 14 and 15 and one shim 16. A fluid reservoir 17 having a hollow shape on the left and right sides is provided on the inner wall surface of one of the divided heads 14. Fluid reservoir 17
It is horizontally recessed inward from the inner wall surface of the split head 14, and a fluid reservoir 17 is formed from the upper surface of the split head 14.
A coating liquid injection port 18 is formed toward the center of the substrate.
Further, a part of the coating liquid injected from the coating liquid injection port 18 is discharged to the outside, and the remaining opening 23 for keeping the injection pressure within a predetermined range.
It has.

The other divisional head 15 has a positioning projection 19 projecting from the upper end edge of the inner wall surface. When assembling 10, both split heads 14,
15 can be aligned. The inner wall surfaces of the split heads 14 and 15 have through holes 14a and 15a.
It is formed flat except for a.

A tapered portion 20 having a triangular cross section is protruded from the inner wall side edges of the lower surfaces of the divided heads 14 and 15 over the entire left and right widths, and the entire lower surface is made of fluorine such as polytetrafluoroethylene (PTFE). Resin 21 is coated. The shim 16 is a thin metal plate,
It has leg pieces 22 on both side ends, and a notched recess 23 is formed between the leg pieces 22.

The two split heads 14 and 15 are combined so as to sandwich the shim 16 between the inner wall surfaces, and the split head 1
4, 15 and the through holes 14a, 15a, 16a of the shim 16
Is screwed into a through hole (female screw hole) 14a of the divided head 14, and the bolt 24 is strongly tightened to form the coating head 10 as shown in FIG.

In the coating head 10 assembled in this way, the slot 26 for shaping the coating liquid is formed between the inner wall surfaces of the divided heads 14 and 15 by the notch-shaped recess 23 of the shim 16.
The lower end of the slot 26 is opened as a nozzle port 25 on the lower surface of the coating head 10, and the opening of the fluid reservoir 17 faces the upper end of the slot 26 and communicates with the inside of the slot 26.

A supply pipe 55 from a coating liquid supply device 50 is connected to the coating liquid inlet 18 of the coating head 10.

In this case, when the coating liquid from the coating liquid tank 200 is directly supplied to the coating liquid injection port 18 through the supply pipe 55, the start of coating varies at a constant cycle as described above, and a streak state occurs. Had been done.

Conventionally, the cause has not been clearly ascertained, and no effective countermeasure has been taken. However, the inventor of the present application believes that nitrogen in the air generally has good compatibility with the resist which is a coating solution, and easily dissolves into the resist. It is assumed that bubbles in the coating liquid flow into the resist to generate pinholes in the coating film, and as shown in FIG. Invented a fluid applicator provided with a gas removing device 100 for removing gas such as air bubbles.

By supplying the coating liquid to the coating liquid head 10 through the gas removing device 100, it is possible to prevent the start of coating from fluctuating at a constant cycle and to prevent the occurrence of a streaking state. That is, a defect whose cause has not been clarified in the past can be solved with a relatively simple configuration.

Hereinafter, the detailed configuration of the coating liquid supply device 50 including the gas removing device 100 of the present embodiment, which can prevent the start of coating from fluctuating at regular intervals and the occurrence of a streaking state, will be described. It is shown in FIG.

In FIG. 5, reference numeral 110 denotes a degassing module,
120 is a vacuum pump, 131 is an on / off valve, 13
2 is a release valve, 133 is a suck-back valve, 140
Is a residual valve. In the example of FIG. 5, the object to be applied is not disc-shaped but rectangular, and is conveyed in the horizontal direction at the lower position of the application head 10 as shown by arrow B in the figure, and the application liquid is applied in a rectangular shape. .

The deaeration module 100 includes a vacuum pump 12
Vacuum chamber 11 maintained at reduced pressure by 0
1, an input-side connection port 112, an output-side connection port 113, and an exhaust port 114. A plurality of gas-permeable membrane tubes 115 are provided between the input-side connection port 112 and the output-side connection port 113 in the vacuum chamber 111. Are linked.

A vacuum pump 120 is connected to the deaeration port 114. During operation, the air in the vacuum chamber 111 is evacuated by the vacuum pump 120 at all times.
The interior is maintained at a low pressure. As a result, the coating liquid from the coating liquid tank 200 sent to the degassing module 110 from the input side connection port 112 flows through the tube 115 formed of a plurality of gas permeable membranes, and is output from the output side connection port 113. Is done.

The air in the vacuum chamber 111 around the tube in the degassing module 110 is exhausted by the vacuum pump 120 and is in a negative pressure state. The gas (dissolved gas) mixed in the coating liquid is a gas permeable film. When the air is degassed into the vacuum chamber 111 via the output port and is output from the output side connection port 113, there is no dissolved gas. Then, the coating liquid from which the dissolved gas has been removed is supplied to the coating head 10.

As the tube of the degassing module 110, for example, it is desirable to use a tube made of PTEE, and to further use a tube made of PTEE which is welded and made into a fluororesin. This deaeration module 110
For example, "Niteps" manufactured by Nitto Denko Corporation
By using a series of products, the dissolved gas in the coating solution can be efficiently removed. The Nitosep series products allow gas (such as gaseous nitrogen) dissolved in the coating liquid to permeate into the vacuum chamber 111 due to the gas concentration difference between the inside and outside of the gas permeable membrane that forms the tube, and has excellent exhaust characteristics. Can be obtained.

The coating solution from which the dissolved gas (eg, gaseous nitrogen) has been removed by the degassing module 110
The on / off valve 131 shown in FIG. Reference numeral 132 denotes a release valve, which closes the on / off valve 131 at the end of the application and simultaneously releases the application liquid in the application liquid supply path by setting the release valve 132 to the open state.

The suck-back valve 133 is provided with a suck-back path in the middle of the application liquid supply path. The valve is brought close to the application liquid supply path during application, and the on / off valve 131 is closed when the application is completed. The suck-back valve 133 is lowered (separated) from the coating liquid supply path, and the coating liquid in the coating liquid supply path is rapidly drawn into the suck-back valve 133, and the coating liquid is drawn into the coating head 10 from the tip end to cause dripping. To prevent

The coating liquid tank 200 of this embodiment is
The airtight housing 210 is filled with a coating liquid for use. Then, a gas (air) controlled to a predetermined pressure by the regulator 300 is sent through the pressurizing pipe 60 between the housing 210 and the application liquid. The inside of the housing 210 is formed in an airtight state, the surface of the coating liquid (for example, resist) is pressurized by the pressurized gas, and the coating liquid is led out to the degassing module 110 via the pipe 58. .

When the coating liquid is allowed to flow out of the coating head 10, the regulator 300 is operated to pressurize gas, for example, nitrogen, into the housing 210 through the pipe 60 to pressurize the coating liquid to form the pipe 58. What is necessary is just to derive.

Further, in the present embodiment, the start of coating varies at a fixed cycle due to the drying of the tip of the head,
The following supply control is performed in order to prevent the occurrence of the streaking state and the application unevenness.

That is, at the present stage, from the end of coating to the start of the next coating, stable coating can be performed within 1 minute and 30 seconds, but if it is longer than that, stable coating cannot be guaranteed as it is. Because of this, the application interval is 1 minute 30
When the time is equal to or longer than the second, dummy ejection control described below is performed.

That is, as shown in FIG. 6, a somewhat flexible liquid draining plate 600 whose top is substantially the same height as the tip of the coating head 10 is disposed near the object to be coated. And O
The N / OFF valve 130 is turned ON for only 3 seconds to discharge the coating liquid from the tip of the coating head 10. The application liquid is dummy-discharged, and after the discharge is stopped, the application head 10 is moved in the direction of the liquid drainage plate 600 and stopped at the shim position to perform the liquid draining operation. At this time, the distance between the coating head 10 and the liquid draining plate 600 is, for example, about 50 μm, and the table speed is set to 0.
% To 100%.

Five seconds after the liquid draining operation, the suck back valve 133 is operated to perform suck back. Accordingly, it is possible to prevent a phenomenon in which the application liquid is exposed at the tip of the coating head 10 and dripping or drying, and the discharge amount of the application liquid becomes unstable.

Although the control shown in FIG. 6 makes it possible to stably provide a good discharge amount of the coating liquid even when the operation interval is long, and to apply the liquid stably, the liquid is applied to the Teflon surface at the head end as shown in FIG. A small amount of the coating liquid remains after the cutting, and the coating may be unstable due to the liquid.

Therefore, if the liquid removal control shown in FIG. 8 is performed, it becomes possible to completely drain the coating liquid. In the control shown in FIG. 8, the distance between the tip of the coating head 10 and the drain plate 600 is set to about 50 μm, the table speed is set to 100%, the liquid is discharged for 3 seconds as in FIG. The plate 600 is moved and drained with respect to the plate 600.
The coating head 10 is again backed, the liquid draining operation is performed on the opposite side of the coating head 10, and control is performed so as to perform suck back after 5 seconds, so that it is possible to completely drain the coating head tip. Become.

In the above description, the drain plate 60
The top of the coating head 10 was moved substantially in parallel with the top of the coating head 10 at substantially the same height as the tip of the coating head 10. However, the present invention is not limited to the above example, and as shown in FIG.
Approximately 3 mm of the coating liquid from the tip of the coating head 10
Control the discharge of the coating liquid for 2 seconds and the discharge stop of the coating liquid.
It may be configured to be passed to 0. Then, at low speed (5
%), The liquid draining operation is made to reciprocate once with respect to the liquid draining plate 600 to perform suck back.

Thus, stable application can be performed by simple adjustment.

Next, a schematic operation of applying the coating liquid of the fluid coating apparatus of the present embodiment having the above-described configuration will be described. When the object to be applied is a disk as shown in FIG. 1, first, the center P of the object to be applied 3 and the rotation center of the table plate 4 are made to coincide with each other so that the table plate of the rotary table device 2 is rotated. The application object 3 is sucked and held on the substrate 4. Then
The coating head 10 is lowered by the air actuator 13, and the coating head 10 is stopped at a predetermined interval between the lower end of the slot 26 of the coating head 10 and the coating target 3. This fixed interval has a size larger than the thickness of the coating liquid 6 flowing out of the slot 26. Thus, the coating head 10 facing the surface of the coating target 3
Is oriented in the radial direction of the application target 3 as shown in FIG. 4, and the end of the slot 26 coincides with the center P of the application target 3. Further, it is preferable that the length of the slot 26 is made substantially equal to the radius of the object 3 to be coated.

Then, as shown in FIG.
Is rotated at a relatively low rotational speed, and the coating liquid injection port 18 is rotated.
When the application liquid 6 is supplied into the fluid reservoir 17 from the, the application liquid 6 is filled in the fluid reservoir 17 and becomes the fluid reservoir 17.
Spread over the entire width of the interior. Further, the coating liquid 6 flows out of the fluid reservoir 17 into the slot 26 by the supply pressure, is adjusted to a uniform film thickness by the slot 26, and
From the coating solution 6 having a uniform film thickness. While applying the coating liquid 6 from the coating head 10,
The film is rotated by 0 ° to form a discharge film on the surface of the application target 3.
At this time, due to the difference between the discharge speed of the coating liquid 6 and the circumferential speed of the coating target 3, the coating liquid 6 having a uniform film thickness discharged from the nozzle port 25 is applied to the surface of the coating target 3. (Conversely, the coating liquid 6 is accumulated at the center of the coating target 3). As a result, on the surface of the application target 3,
A coating film having a relatively large thickness at the center of the application target 3 and having a smaller thickness toward the outer periphery is formed.

Thereafter, the coating head 10 is raised again,
When the table plate 4 is rotated at a high speed, the coating solution 6 at the center is spread and leveled in the outer peripheral direction due to centrifugal force, and an extremely thin coating film having a uniform film thickness is obtained. In addition, the film thickness of the coating film can be made a constant film thickness determined by the viscosity of the coating solution 6, the number of rotations of the table plate 4, and the like, and a coating film with high film thickness accuracy can be obtained. The coating liquid 6 separated from the coating target 3 by the centrifugal force is prevented from scattering around by the cover 7 and is recovered by the cover 7.

When the fluid coating apparatus A is used in this manner, a uniform coating film with high precision can be formed on the lower coating target 3 having a disc-like shape or any other shape, particularly a coating target 3 having a different shape other than a rectangular shape. A thick coating film can be formed. In addition, since a coating film having a film thickness close to the target film thickness can be formed first by the slot-type coating head 10, the amount of the coating liquid 6 discharged at the time of leveling can be extremely reduced, and the spin coater can be formed. The amount of consumption of the coating liquid 6 can be greatly reduced as compared with the case of FIG. For this reason, the cost of the coating liquid 6 can be greatly reduced and the trouble of waste liquid treatment can be simplified.

In this embodiment, the slot 2
6 has the same dimension over the length direction, so that the coating liquid 6 is greatly stretched and thinned in the outer peripheral portion where the circumferential speed is high, and compared in the inner peripheral portion where the circumferential speed is small. It becomes thicker. In order to reduce the difference in film thickness between the inner peripheral side and the outer peripheral side of the coating film before leveling, the width w of the slot 26 is changed, and the width w of the slot 26 on the inner peripheral side is changed.
Should be made thinner and thicker on the outer peripheral side. Alternatively, it is conceivable that the coating liquid injection port 18 is provided at an end located on the outer peripheral side of the slot 26 to bias the pressure applied to the coating liquid 6.

When the application target 3 is rectangular as shown in FIG. 5, the application target is brought into close contact with a transport unit (not shown) by suction or the like, and is transported to the lower portion of the coating head 10. Then, the coating head 10 is lowered by the air actuator 13, and the coating head 10 is stopped at a predetermined interval between the lower end of the slot 26 of the coating head 10 and the coating target 3. This fixed interval has a size larger than the thickness of the coating liquid 6 flowing out of the slot 26.

Subsequently, when the coating liquid 6 is supplied from the coating liquid inlet 18 into the fluid reservoir 17, the coating liquid 6 fills the fluid reservoir 17 and spreads over the entire width of the fluid reservoir 17. Further, the application liquid 6 is supplied to the fluid reservoir 1 by the supply pressure.
7 flows into the slot 26, is adjusted to a uniform film thickness by the slot 26, and flows out from the nozzle port 25 at the lower end as the coating solution 6 having a uniform film thickness. The application target 3 is conveyed at a predetermined speed in the direction of arrow B in FIG. 5 while discharging the application liquid 6 from the application head 10, and a discharge film is formed on the surface of the application target 3. At this time, due to the difference between the discharge speed of the coating liquid 6 and the transport speed of the coating target 3, the coating liquid 6 having a uniform thickness discharged from the nozzle port 25 is applied to the surface of the coating target 3. The coating liquid 6 is thinly spread (conversely, the coating liquid 6 is accumulated at the center of the coating target 3).

Thereafter, the coating head 10 is raised again,
The application of the application liquid is completed.

[0057]

As described above, according to the present invention, the fusing gas in the coating liquid can be reliably removed, and the coating liquid can be uniformly applied from the tip of the coating head. The coating liquid can be applied to the surface of the substrate with a uniform thickness.

As a result, it is possible to effectively prevent the start of application from fluctuating at a constant cycle or a streaking state, and the occurrence of a defect in a manufactured part due to a slight application unevenness.

[0059]

[Brief description of the drawings]

FIG. 1 is a partially broken schematic front view showing an example of a fluid application device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the coating head of the embodiment shown in FIG.

FIG. 3 is a cross-sectional view of the coating head of the embodiment shown in FIG.

FIG. 4 is a view for explaining a coating step of a coating liquid by a coating head.

FIG. 5 is a diagram illustrating a detailed configuration of a coating liquid supply device according to the present embodiment.

FIG.

FIG.

FIG.

FIG. 9 is a diagram for explaining a liquid draining mechanism of the fluid application device according to the embodiment.

FIG. 10 is a view for explaining an application step of an application liquid by an application head according to the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 coating device main body 2 rotary table device 3 coating target 4 table plate 5 drive unit 6 coating liquid 7 cover 8 detector 9 control unit 10 coating head 11 arm 12 support unit 13 air actuator 14, 15 split head 16 shim 17 fluid reservoir REFERENCE SIGNS LIST 18 coating liquid inlet 21 fluororesin coating 24 bolt 23 shim notch recess 26 coating liquid shaping slot 50 coating liquid supply device 100 gas removing device 200 coating liquid tank 300 regulator 110 degassing module 111 vacuum chamber 112, input side Connection port 113 Output side connection port 115 Gas permeable membrane tube 120 Vacuum pump 131 On / off valve 132 Release valve, 133 Suck back valve 200 Coating liquid tank 210 Housing 300 Regulator 310 Nitrogen cylinder 60 Draining board

Claims (3)

[Claims] 1. A fluid coating apparatus for forming a substantially uniform coating film having a predetermined thickness by applying a coating fluid on a coating effective surface of a coating target member in which at least a coating target portion is formed in a flat plate shape. A coating head that has an opening in the shape of an arrow and applies the coating fluid by flowing the coating fluid through the opening; and coating the coating target member by scanning the coating head on a coating effective surface of the coating target member. Coating head scanning means for applying a coating fluid on the effective surface; gas removing means for removing gas mixed in the coating fluid supplied to the coating head; and the gas provided between the gas removing means and the coating head. A fluid control device for controlling a supply of the coating fluid supplied from the removing unit to the coating head. 2. The application target portion is a liquid crystal display substrate, and the application fluid is a coating fluid applied to the substrate in a manufacturing process of the liquid crystal display substrate, such as a photoresist, an insulating material, or a solder resist; The gas removing means passes the coating fluid through a passage having a gas permeable membrane disposed therearound, and maintains the outside of the gas permeable membrane in a negative pressure state so that the gas in the coating fluid passes through the gas permeable membrane. 2. The fluid applying device according to claim 1, further comprising an exhaust unit for removing the fluid. 3. A fluid applying method in a fluid applying apparatus including an application head having a slit-shaped opening and applying the application fluid by flowing out the application fluid from the opening, wherein the application target member is applied. When the application head is scanned on the effective surface to apply the application fluid on the application effective surface of the application target member, the application fluid is supplied to the application head after removing gas mixed in the application fluid. A method of applying a coating fluid onto a coating effective surface of a member to be coated to form a substantially uniform coating film having a predetermined thickness.