WO2007116609A1

WO2007116609A1 - Preliminary discharge device and preliminary discharge method

Info

Publication number: WO2007116609A1
Application number: PCT/JP2007/052730
Authority: WO
Inventors: Hirotsugu Kumazawa; Hidenori Miyamoto; Yoshiaki Masu; Kenji Yoshizawa
Original assignee: Tokyo Ohka Kogyo Co., Ltd.
Priority date: 2006-03-31
Filing date: 2007-02-15
Publication date: 2007-10-18
Also published as: TW200738350A; KR101005955B1; KR20080094825A; JP4986490B2; JP2007268391A

Abstract

[PROBLEMS] To realize a preliminary discharge device which doesn’t require a enlarged size and a high machining accuracy for roller itself, and an amount of consumption of a washing fluid can be relatively smaller and the running cost can be lowered. [MEANS FOR SOLVING THE PROBLEMS] In a preliminary discharge device for discharging a coating liquid from a slit nozzle (3) prior to coating of a substrate (W) with the coating liquid, a preliminary discharge surface (20) is disposed to face the slit nozzle (3) and extends in the same direction as the extending direction of the slit opening in the slit nozzle (3), and a removal mechanism (21) for removing the coating liquid existing on the surface of the preliminary discharge surface (20) is installed near the preliminary discharge surface (20).

Description

Specification

Pre-discharge device and pre-discharge method

Technical field

The present invention relates to a preliminary discharge apparatus and a preliminary discharge method for a slit coater for applying a coating liquid such as a resist onto the surface of a substrate such as a glass substrate or a semiconductor wafer.

Background art

[0002] When a coating solution is coated on the surface of a substrate using a slit coater, the coating solution at the tip of the slit nozzle comes into contact with air during the waiting period until the coating is performed on the next substrate after the coating operation is completed. As a result, the concentration of the coating liquid partially increases, and the viscosity of the coating liquid partially increases.

When the coating operation is performed in such a state, uneven coating such as vertical stripes and film breakage occur due to uneven viscosity.

In order to eliminate such problems, a preliminary discharge process is performed in which a small amount of coating liquid existing near the opening of the slit nozzle is discharged prior to supplying the coating liquid to the substrate.

[0003] As a preliminary ejection device that performs such preliminary ejection processing, a roller-type preliminary ejection device that uses a priming roller and ejects a small amount of coating liquid onto the priming roller is known (for example, Patent Documents). 1).

In this preliminary discharge device, the priming roller is immersed in the cleaning tank in which the cleaning liquid is stored, and the coating liquid discharged from the slit nozzle is scraped off by the squeegee as the priming roller rotates. The

[0004] Patent Document 1: Japanese Patent Laid-Open No. 2005-329340

Disclosure of the invention

Problems to be solved by the invention

By the way, the roller-type pre-discharge device as described above has a disadvantage that the device itself has a large volume due to the need for a cleaning tank that accommodates the roller itself, and the device itself becomes large. Also, as the substrate to be coated becomes larger, the roller also becomes larger, so the processing accuracy of the roller is increased. There were drawbacks that made it difficult to maintain. Furthermore, in the case of the roller method, it has been pointed out that the consumption of the cleaning liquid becomes large because the priming roller is immersed in the cleaning liquid, and the running cost is also increased.

In addition, in order to keep the entire roller clean, a squeegee longer than the slit length of the slit nozzle (for removing the coating liquid force on the roller surface) is required. In addition, it is difficult to maintain accuracy with respect to the provision of such a large squeegee at a predetermined angle with respect to the roller. In addition, when a defect occurs in the cleaning of the roller, there is a drawback that the defect tends to adversely affect the coating itself.

In view of the above, the present invention realizes a preliminary discharge apparatus and a preliminary discharge method without increasing the size of the apparatus itself and without requiring high V and processing accuracy for the roller itself. Furthermore, another object of the present invention is to realize a preliminary discharge apparatus and a preliminary discharge method in which the consumption of the cleaning liquid is relatively small and the running cost is low.

Means for solving the problem

[0007] The preliminary ejection device of the present invention is a preliminary ejection device for ejecting a coating liquid such as a slit nozzle force prior to application to the substrate surface, and is disposed facing the slit nozzle. A configuration in which a preliminary discharge surface extending in the same direction as the slit nozzle extension direction of the slit nozzle and a removal mechanism for removing the coating liquid existing on the surface of the preliminary discharge surface are provided in the vicinity of the preliminary discharge surface When

To do.

[0008] According to the preliminary ejection device of the present invention, the preliminary ejection surface that is arranged to face the slit nozzle and extends in the same direction as the extension direction of the slit opening of the slit nozzle, and the vicinity of the preliminary ejection surface In addition, a removal mechanism for removing the coating liquid present on the surface of the preliminary ejection surface is provided, so that the actual preliminary ejection processing is performed by ejecting the coating liquid onto the preliminary ejection surface (virtual substrate). Is possible. This makes it possible to obtain a simple structure without the need for providing a drive device as compared with, for example, a roller-type pre-discharge device, and to suppress an increase in size of the device. In addition, manufacturing costs can be reduced. In addition, the roller system is not used! [0009] The preliminary ejection method of the present invention is a preliminary ejection method for ejecting a coating liquid such as a slit nozzle force prior to application to the substrate surface, wherein the slit nozzle applies the coating liquid to the substrate surface. While supplying, the removal mechanism is moved on the preliminary discharge surface extending in the same direction as the slit nozzle extending direction so that the coating liquid remaining on the preliminary discharge surface is removed. To.

According to the preliminary discharge method of the present invention, while the slit nozzle supplies the coating liquid to the substrate surface, the removal is performed on the preliminary discharge surface extending in the same direction as the extension direction of the slit opening of the slit nozzle. Since the coating liquid remaining on the preliminary discharge surface is removed by moving the mechanism, the preliminary discharge processing can be performed more easily than, for example, the roller-type preliminary discharge method, and the processing efficiency can be improved. Can do. Further, during the preliminary discharge process, for example, the coating liquid can be removed by the movement of the removal mechanism which only needs to supply a small amount of cleaning liquid to the preliminary discharge surface. The consumption of can be greatly reduced.

The invention's effect

[0011] According to the preliminary discharge device of the present invention, it is possible to obtain a preliminary discharge device that is structurally simple and inexpensive.

In addition, according to the preliminary discharge method of the present invention, it is possible to improve the processing efficiency of the preliminary discharge process and reduce the cleaning liquid.

Brief Description of Drawings

FIG. 1 is a plan view showing an example of a slit coater.

FIG. 2 is a cross-sectional view of the slit coater shown in FIG.

FIG. 3 is a schematic block diagram (No. 1) showing an embodiment of a preliminary discharge device according to the present invention. FIG. 4 is a schematic block diagram showing an embodiment of a preliminary discharge device according to the present invention (No. 1). 2)

FIG. 5 is a side view showing details of the removal mechanism of the preliminary ejection device shown in FIGS. 3 and 4. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are schematic configuration diagrams of a slit coater including the preliminary ejection device of the present invention. FIG. 1 is a plan view and FIG. 2 is a cross-sectional view taken along line AA in FIG. 3 and 4 are schematic configuration diagrams of the preliminary ejection device, and FIG. 5 is a side view showing details of the removal mechanism of the preliminary ejection device. As shown in FIGS. 1 and 2, the slit coater has a base 1 as shown in FIG. The base 1 is provided with a pair of rails (2a, 2b). On the rails (2a, 2b), a moving device 4 on which the slit nozzle 3 is mounted is movably disposed, and a substrate mounting stage 5 is disposed at substantially the center of the rails (2a, 2b). Then, a substrate W such as a glass substrate or a semiconductor wafer is disposed on the substrate mounting stage 5, and a coating liquid such as a resist is applied to the surface of the substrate W. The moving device 4 includes drive units (6a, 6b) that engage the rails (2a, 2b) and beams (7a, 7b) installed between these drive units.

[0014] The slit nozzle 3 is supported between two drive devices (6a, 6b) so as to be movable up and down.

A slit opening extending in a direction orthogonal to the extending direction of (2a, 2b) is provided, and the coating liquid is applied to the surface of the substrate W through the slit opening. The slit nozzle 3 communicates with a syringe pump (not shown) and communicates with a coating liquid supply tube (not shown) to supply a single coating liquid. After one application, the excess coating solution is collected through the discharge tube.

[0015] When applying to the surface of the substrate W, for example, a slit nozzle is used by using a gap sensor.

The distance between the slit nozzle 3 and the surface of the substrate W is measured, and an elevating device (not shown) is driven to adjust the distance between the slit nozzle 3 and the surface of the substrate W to be maintained at a predetermined distance.

In the present embodiment, in particular, the preliminary discharge device is configured as shown below in the preliminary discharge unit 10 provided at a position away from the substrate mounting stage 5. That is, as shown in FIGS. 3 and 4, the preliminary ejection device is disposed so as to face the slit nozzle 3, and the preliminary ejection surface 20 extends in the same direction as the extension direction of the slit opening of the slit nozzle 3. And a removing mechanism 21 that removes the coating liquid present on the surface of the preliminary ejection surface 20.

The preliminary discharge surface 20 is formed by a plate-like plate, and the plate 20 is a drain pan 22. The slit nozzle 3 extends in the same direction as the slit opening direction. Although not shown, the drain pan 22 has a cleaning liquid supply mechanism for cleaning the drain pan 22 itself. It also has an exhaust mechanism for exhausting the drain pan 22. Both ends (20a, 20b) of the plate 20 are chamfered. By chamfering in this way, as will be described later, when the squeegee 22 moves on the plate 20, the squeegee 22 is influenced by both ends (20a, 20b) of the plate 20 (breakage due to contact, etc.). Can be prevented.

As shown in FIG. 5, the removal mechanism 21 includes a main body 24 to which a squeegee 23 is attached, and a cleaning liquid supply mechanism 25, a drying mechanism 26, and a suction mechanism 27 attached to the main body 24. ing.

[0019] When the removal mechanism 21 is arranged on the plate 20 as shown in the figure, the drying mechanism 26 is provided upstream of the main body 24 and the cleaning liquid is supplied downstream of the main body 26 based on the movable direction (see arrow A). A mechanism 25 is mounted to be placed. The suction mechanism 27 is attached to the opposite side of the main body 24 to the side where the squeegee 23 is attached. The main body 30 is movably attached with respect to the fulcrum X.

Note that the attachment positions of the cleaning liquid supply mechanism 25, the drying mechanism 26, and the suction mechanism 27, the orientation of the main body 24 with respect to the plate 20 and the like are not limited to the illustrated case, and various forms are conceivable depending on the situation.

In the removing mechanism 21 having such a configuration, the pressing panel provided in the driving mechanism (not shown) presses itself against the plate 20 and the squeegee 23 is also pressed against the plate 20. Then, it moves integrally in the same direction (longitudinal direction) as the direction in which the opening of the slit nozzle 3 extends and performs a preliminary discharge process as described later. When the coating liquid is not discharged onto the plate 20, the removal mechanism 21 temporarily moves upward from the plate 20, moves in a direction perpendicular to the plate 20 (see arrow B), and returns to the standby position. That is, it moves to the side of the plate 20.

The end portion (lower end) of the squeegee 23 is pressed against the surface of the plate 20 as described above, and an elastic pressure contact force acts between the squeegee 23 and the surface of the plate 20. The abutment angle of the squeegee 23 against the plate 20 can be adjusted within a range of, for example, 30 to 75 degrees (preferably 45 to 60 degrees). At this angle, squeegee 23 is abutted against plate 20 As a result, the effect of removing the coating liquid can be enhanced.

[0022] The squeegee 23 is preferably a squeegee 23 having a lower hardness than the plate 20 and having a solvent resistance and an elastic material strength. In the present embodiment, a force using polyester can be used besides this, for example, a rubber material force capable of elastic deformation.

The cleaning liquid supply mechanism 25 is provided with a cleaning liquid supply hole 29 for supplying a cleaning liquid. The cleaning liquid supply mechanism 25 may have any configuration that can supply cleaning liquid onto the plate 20. Various forms of supply pipes, nozzles, and the like are possible. For example, different types may be provided on the plate 20 by providing a plurality of nozzles. The cleaning liquid can also be supplied. In addition to this, the cleaning liquid can be supplied not only to the plate 20 but also to the squeegee 23 by changing the direction of the nozzle or the supply angle of the cleaning liquid having the nozzle force. In this case, it is not necessary to separately provide a cleaning liquid supply mechanism for the squeegee 23, and the configuration can be simplified.

The drying mechanism 26 is provided with an air supply hole 28 for supplying air. The drying mechanism 26 is similar to the cleaning liquid supply mechanism 25 as long as it is configured to supply air onto the plate 20, and various forms of supply pipes, nozzle shapes, and the like are conceivable. For example, air can be supplied not only to the plate 20 but also to the squeegee 23 by changing the nozzle direction or the air supply angle from the nozzle. In this case, there is no need to provide a separate drying mechanism for the squeegee 23. Can be simplified.

[0025] When a cleaning liquid supply mechanism or a drying mechanism for the squeegee 23 is separately provided, the vicinity of the plate 20 (upper side, lower side, lateral side, etc.), the vicinity of the movement end point position of the removal mechanism 21, the removal mechanism 21 It can be provided near the standby position. It can also be integrated into the removal mechanism 21 as a single unit.

[0026] Although not shown, the suction mechanism 27 is a suction mechanism that leads to the vicinity of the squeegee 23 through the body 24.

Nozzle force for I is configured.

[0027] According to such a preliminary discharge device of the present embodiment, the plate 20 extending in the same direction as the extending direction of the slit opening of the slit nozzle 3, and the plate 20 Since there is a removal mechanism 21 that removes the coating liquid present on the surface, if it is actually moved on the plate 20 as described later, the plate (virtual substrate) 20 is the same as the regular coating process. The coating liquid is discharged onto the plate 20 by the removal mechanism 21. It is possible to perform an easy preliminary discharge process of removing (for example, as compared with a roller type preliminary discharge device).

That is, in the case of the present embodiment, since the squeegee 23 having a width substantially equal to the width of the plate-like plate 20 is simply moved in the direction in which the opening of the slit nozzle 3 extends, The drive mechanism and the squeegee longer than the slit length are not required to have high precision in the required mouth ring itself or the way of attaching the squeegee. Thus, since a high processing accuracy is not required and a large drive device is not required, a simple device structure with reduced manufacturing cost can be obtained.

[0028] Since the removal mechanism 21 is composed of the squeegee 23, the cleaning liquid supply mechanism 25, and further the drying mechanism 26 and the suction mechanism 27, when it is actually moved on the plate 20 as described later, The coating solution on the plate 20 can be softened with the cleaning solution and scraped off with the squeegee 23. Furthermore, the coating liquid scraped off by the suction mechanism can be directly sucked, and the plate 20 after being wiped off can be dried in a clean state.

Next, an embodiment of an actual preliminary discharge method (preliminary discharge process) using the above-described preliminary discharge device will be described. In the present embodiment, the pre-ejection unit 10 is set as the start position when coating.

[0030] When the regular coating process on the substrate W is completed, the slit nozzle 3 returns to the preliminary ejection unit 10 at the start position as shown in FIG. Then, a predetermined amount of coating liquid is discharged (supplied) from the slit nozzle 3 to the plate 20 by the same operation as in the regular coating process.

At this time, the slit nozzle 3 descends so as to approach the plate 20, and descends to form a bead, for example, until the distance between the tip of the slit nozzle 3 and the surface of the plate 20 becomes, for example, 30 μm. Thereafter, the slit nozzle 3 is raised to, for example, about 150 to 200 m, and during that time, the coating liquid supply speed such as the pump force is increased to the application speed to the substrate W, and the slit nozzle 3 is increased.

Is moved to discharge a predetermined amount of coating liquid.

[0031] After the coating liquid is discharged onto the plate 20, the slit nozzle 3 moves onto the substrate W and returns to the normal coating process on the substrate W again. Specifically, when the linear motor is driven, the moving device 5 moves toward the right side of the drawing, and a coating solution such as a resist is supplied from the slit nozzle 3 to the surface of the substrate W. When the regular coating process on the surface of the substrate W is completed, the slit nozzle 3 moves up and down and returns to the start position.

[0032] When the normal coating process on the next substrate W starts to be performed again in this way, the preliminary ejection unit 10 removes it.

The removal mechanism 21 operates to start removing the coating solution on the plate 20.

That is, the removal mechanism 21 also moves on the plate 20 in the standby position force, and is disposed opposite to the plate 20 as shown in FIGS. Then, the cleaning liquid is supplied onto the plate 20 from the cleaning liquid supply mechanism 25.

Next, the removal mechanism 21 moves one end force on the plate 20 to the other end (arrow A in FIGS. 4 and 5), so that the coating solution on the plate 20 is scraped off by the squeegee 23. At this time, the viscosity of the coating solution is lowered by the cleaning solution, and the force on the plate 20 can be wiped off cleanly. In conjunction with this force removal operation, the suction mechanism 27 is driven to suck the coating liquid directly on the squeegee 23.

Note that the suction can be performed when the squeegee 23, which does not have to be synchronized with the force removal operation, reaches the movement end point. In addition, the removal mechanism 21 may be moved several times instead of once.

Next, air is supplied onto the plate 20 from the drying mechanism 26 to dry the plate 20. Thereafter, the removal mechanism 21 is also released upwardly with the force on the plate 20 and moved in a direction perpendicular to the plate 20 (see arrow B in FIG. 4) to return to the standby position.

For example, when the squeegee 23 is also washed with a washing liquid and dried, it depends on the location where the washing liquid supply mechanism and the drying mechanism are provided (the removal mechanism 21 is integrated with the separation mechanism 21 or is provided separately. Before returning to the standby position (after the plate 20 has dried) or returning to the standby position, force is applied.

[0035] According to the preliminary discharge method of the present embodiment as described above, since the application liquid is discharged onto the plate 20 and the cleaning liquid is supplied, and then the simple method is simply squeezed by the squeegee 23. The processing efficiency can be improved compared to the pre-discharge method of the roller method. Also, during pre-discharge process In this case, it is only necessary to supply a small amount of cleaning liquid from the cleaning liquid supply mechanism 25 onto the plate 20, and for example, the consumption of cleaning liquid can be greatly reduced as compared with the roller type preliminary discharge method.

In addition, since the coating solution attached to the squeegee 23 is directly sucked by the suction mechanism 27, the squeegee 23 can always be in a state close to that after cleaning, and the maximum force removal effect can be maintained during processing. . In addition, since the plate 20 after the force is removed is dried by the drying mechanism 26, the plate 20 can always be kept clean.

In addition, when not only the plate 20 but also the squeegee 23 is washed and dried, the preliminary ejection process can be performed in a cleaner environment.

[0036] In the preliminary ejection device of the above-described embodiment, a plate-like plate is used as the preliminary ejection surface 20, but a belt-like one can also be used.

For example, if the belt is configured to be able to rotate and move in the form of a roller, it can be applied in the same manner as the configuration of this embodiment (FIGS. 3 and 4) by contacting a fixed squeegee against the rotating belt.

The cloth liquid can be swept away. In this case, the position of the squeegee is not particularly limited because the squeegee only needs to contact the belt!

In the preliminary ejection device of the above-described embodiment, the case where the removal mechanism 21 includes the squeegee 23 and the cleaning liquid supply mechanism 25, and further the drying mechanism 26 and the suction mechanism 27 has been described. It is not limited to this. In other words, when the viscosity of the coating solution is low and it is not necessary to soften the cleaning solution, only the squeegee 23 is sufficient if it has at least the squeegee 23 in terms of simply removing the coating solution on the plate 20. A mechanism for removing this is also conceivable. In addition, a removal mechanism comprising a squeegee 23 and a cleaning liquid supply mechanism 25 is also conceivable.

Thus, it goes without saying that the configuration of the removal mechanism 21 can be further simplified depending on the situation. Of course, the removal mechanism 21 has the above-described configuration, and during the actual processing, it is also possible to exclude the necessary steps (without performing the steps).

[0038] In the preliminary ejection device of the above-described embodiment, the force described in the case where the squeegee 23 is used in the removing mechanism 21 may be used, for example, a brush, an air knife, or a sponge. it can.

Further, in the preliminary discharge device of the above-described embodiment, the case where one squeegee 23 is provided in the removal mechanism 21 has been described, but a configuration in which a plurality of squeegees are provided may be employed. In this case, each squeegee may be formed from the same material cover or from different materials. With such a configuration, the scraping effect can be greatly improved compared to the case of just one.

It is also possible to combine a squeegee and a brush or an air knife, or to combine a brush and an air knife.

In addition, by combining squeegee and sponge, brush and sponge, or air knife and sponge, for example, it is possible to take off the coating liquid and clean (wipe off) the plate with a synergistic effect. Can be expected.

[0039] In the preliminary ejection device of the above-described embodiment, the plate 20 is inverted by 90 degrees, for example.

(Vertical) The configuration is such that the removal solution 21 attached to the side surface removes the coating solution on the plate 20, or the plate 20 is inverted 180 degrees after the coating solution is discharged onto the plate 20 from the slit nozzle 3. Then, remove the coating solution with the removal mechanism 21 attached to the lower surface of the plate 20.

[0040] In addition, the preliminary ejection device according to the above-described embodiment may be configured such that, for example, the tip of the squeegee 23 is separated from the plate 20 at the end portion of the plate 20 (away from the plate 20 upward). For example, when the movement stops during processing, the tip of the squeegee 23 moves away from the plate 20 at the end of the plate 20, thereby eliminating the problem that the coating liquid that does not adhere to the squeegee 22 remains on the plate 20, and the surface of the plate 20 is tally. Has the advantage of being maintained

In addition to this, a drive mechanism may be provided on the plate 20 so that the plate 20 is separated from the removal mechanism 21 (squeegee 22).

[0041] In the preliminary ejection device of the above-described embodiment, the removal mechanism 21 can supply at least the cleaning liquid onto the plate 20, and the force on the plate 20 only needs to be able to remove the coating liquid. Therefore, as in the above-described embodiment. However, it is not limited to the configuration in which the plate 20 is located on the upper side of the plate 20, and can be installed on the side of the plate 20, for example, depending on the arrangement position of the plate 20. Immediately In other words, the installation position of the removal mechanism 24 may be on the upper side, the lower side, or the side of the plate 20.

In the preliminary ejection method of the above-described embodiment, after the coating liquid is ejected from the slit nozzle 3 onto the plate 20, the cleaning liquid is ejected onto the plate 20 before squeezing with the squeegee 22.

Force If the viscosity is low, it is possible to squeeze the coating solution with the squeegee 22 without spraying the cleaning solution.

[0043] Further, the preliminary ejection device of the above-described embodiment is also applied to a double gantry system having two pairs of gantry on the force base described for the slit coater having only one gantry that accommodates the slit nozzle. be able to.

It should be noted that the present invention is not limited to the above-described embodiments, and various other configurations can be taken within the scope without departing from the gist of the present invention.

Claims

The scope of the claims

[1] In a preliminary discharge device for discharging the coating liquid from the slit nozzle prior to coating on the substrate,

A pre-ejection surface that is disposed opposite to the slit nozzle and extends in the same direction as the slit opening of the slit nozzle;

A pre-ejection apparatus characterized in that a removal mechanism for removing the coating liquid existing on the surface of the pre-ejection surface is provided in the vicinity of the pre-ejection surface.

[2] The preliminary ejection device according to [1], wherein the removal mechanism includes a squeegee and a cleaning liquid supply mechanism.

[3] The preliminary ejection device according to [2], wherein the removal mechanism also has a drying mechanism and a suction mechanism.

4. The preliminary ejection device according to claim 2, wherein the squeegee is also formed with a polyester force!

5. The preliminary ejection device according to claim 2, wherein a plurality of the squeegees are provided.

6. The preliminary ejection device according to claim 1, wherein the preliminary ejection surface is a plate-like plate, and one or both ends of the plate are chamfered.

[7] In the pre-discharge method for discharging the coating liquid from the slit nozzle prior to coating on the substrate surface,

While the slit nozzle supplies the coating liquid to the substrate surface, the removal mechanism is moved on the preliminary discharge surface extending in the same direction as the slit nozzle extending direction of the slit nozzle. A pre-discharge method, wherein the coating liquid remaining on the pre-discharge surface is removed.

[8] In the preliminary ejection method according to claim 7, after the coating liquid remaining on the preliminary ejection surface is dissolved with a cleaning liquid, the dissolved coating liquid is removed with a squeegee, and then the preliminary ejection surface is dried. A preliminary discharge method characterized in that

[9] The preliminary ejection method according to claim 8, wherein the squeegee is washed. A preliminary discharge method characterized by:

10. The preliminary discharge method according to claim 7, wherein the movement of the removal mechanism is repeated a plurality of times.

11. The preliminary discharge method according to claim 7, wherein after the coating liquid remaining on the preliminary discharge surface is removed, the preliminary discharge surface is washed with a cleaning liquid and dried.