JP2001070858A - Paint coater and coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paint coater by which the film thickness is stabilized, and the film thickness is kept constant. SOLUTION: A paint is supplied to a paint discharge head 1 by a paint feeder, and at least one between a stage for holding a material 5 to be coated and the discharge head is relatively moved to form a coating film on the material surface by this coater used in sheet coating. A discharge slit 2 and a recovery slit 8 are provided in the discharge head 1, and one rod bar 3 is arranged at the tips of both slits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-wafer coating method, and more particularly to a method for performing single-wafer coating using a slit for precision coating. In addition to forming a coating film on a substrate in order to create a color filter and wiring for a flat display such as a liquid crystal display, etc., there is also a UV coating layer coating in an optical filter manufacturing field such as a resist coating in a semiconductor manufacturing field. It is suitable for a case where a liquid paint such as a coating is applied thinly and uniformly on the surface of a material to be coated supplied in a single-wafer method.

[0002]

2. Description of the Related Art Conventionally, various paints have been thinned on a substrate having a short length in a coating direction, such as a plastic substrate for an optical filter, a glass substrate for a liquid crystal display, and a glass substrate for a color filter. In addition, there is a strong demand for uniform application. In order to form a coating film on such a substrate industrially, a single-wafer coating method is used in which the material to be coated is supplied one by one to a coater, the coating material is applied, and the coating material is conveyed to the next process such as drying. are doing.

As a method for forming a coating film on such a material to be coated, a spin coater, a bar coater, and a roll coater are widely used.

[0004] Among them, a method using a spin coater is as follows.
This is a method widely used for coating a photoresist on a semiconductor wafer, and a coating film can be formed by dropping a coating material on the center of the surface of a rotating workpiece. The coating film obtained by this method can have a film thickness which is fairly accurately uniform over the entire range by setting the kind of the paint suitable for the method. However, the amount of paint used to obtain a coating film having a predetermined thickness is extremely large, which is uneconomical. In addition, paint may adhere to the edges and the back surface of the material to be coated, or the paint scattered in the apparatus may be gelled or solidified, resulting in poor process stability and cleanliness. It causes quality deterioration.

A method using a roll coater is a method of transferring a coating material to a material to be coated via a rubber roll, and is used for coating a long material to be coated or a roll-shaped material to be wound. It can be performed. However, since the paint is sequentially sent from the pan to the application roll and then to the material to be coated, the paint is exposed to the air for a long time. Also easily occur. As a result, the quality of the coated product is reduced.

The method using a bar coater is a method in which a coating material is applied to a material to be coated using a bar in which a thin wire is wound around a rod. In this method, the wire wound on the rod comes into contact with the material to be coated, so there is an inconvenience that streaks of the coating film easily enter.

In view of such inconvenience, it has recently been proposed to use a method called a slit coater or a die coater (hereinafter referred to as a die coater). Japanese Patent Application Laid-Open Nos. 5-1105 and 5-1424 disclose application of a die coater to the production of a color filter.
07, and JP-A-6-339656.

[0008] Die coaters have been widely used for thick film coating and continuous application of high-viscosity paints. If a die coater is used to form a coating film on a material to be coated, US Pat. No. 4,230,793, U.S. Pat.
Coating methods such as a curtain flow method, an extrusion method, and a bead method are known as described in US Pat. No. 6,885 and US Pat. No. 2,761,791. Above all, in the above-mentioned bead method, paint is discharged from a slit provided in a die coater die, and a paint pool called a paint bead is formed between the die and a work material that relatively moves while maintaining a certain interval. Then, in this state, the paint is drawn out as the material to be coated travels to form a coating film. If the bead method is used to continuously form coating films by supplying the same amount of paint from the slits as the paint consumed by coating film formation, the formed coating film will have considerable film thickness uniformity. High accuracy can be achieved. Also,
Since there is almost no waste of the paint and the paint feed path is sealed until the paint is discharged from the slit, deterioration of the paint and mixing of foreign substances can be prevented, and the quality of the obtained coating film can be maintained at a high level.

[0009]

However, if an attempt is made to form a coating film by using a bead method with a die coater on a material supplied in a single-wafer system, the coating on the material to be coated is not possible. Inevitably becomes intermittent, so regardless of whether the paint is being discharged continuously or intermittently, the paint is applied at the coating start position and coating end position of the material to be coated. The bead is disturbed or the paint bead disappears. Then, it becomes difficult to maintain a stable coating bead suitable for coating over the entire range of coating, and a uniform coating film cannot be obtained until the coating bead becomes stable.

[0010] Such inconvenience occurs similarly in the case of a short workpiece and a long workpiece, but in the case of a short workpiece. , While the ratio of the length to obtain a coating film of uniform thickness with respect to the entire length is small,
In the case of long coated materials, this ratio increases,
As described in JP-B-43-24133, "bead coating cannot be applied to a continuous support because an intermittent support cannot maintain a stable bead." Coating by a die coater was performed on the material to be coated. Also, Japanese Unexamined Patent Publication No.
Neither -11105 nor JP-A-5-142407 does not disclose the inconvenience of coating these short intermittent supports and the means for solving them. Also,
In Japanese Patent Application Laid-Open No. Hei 6-339656, pressurizing is applied to the paint supply means only in advance of coating for a time estimated in advance in order to compensate for a time delay of liquid sending which is unavoidable in principle due to the use of pressurized feeding. However, there is no description of a method for controlling the formation or disappearance of a paint bead or a method of suppressing the disturbance of a paint bead. In this case, too, the proportion of the length of the material to be coated that cannot be effectively utilized is large. Therefore, waste of the material to be coated is significantly increased. In other words, since the ratio of the length of the coating film having a uniform thickness to the entire length of the material to be coated is small, the effective use ratio for the material to be coated is only small. The features of the die coater such as economy, high-precision thin film coating, and paint tightness cannot be effectively utilized.

[0011] Among the known techniques, there are disclosures of techniques focusing on these coating start portions. For example, even in the case of coating on a continuous support, Japanese Unexamined Patent Publication No. 1-213641 discloses an unstable coating by temporarily increasing or decreasing the pressure applied before and after the bead at the start of coating in which the web approaches the coating machine. It is described that the state of the bead at the forefront is stabilized, and a method of promoting bead formation by temporarily increasing the discharge speed of the paint as described in JP-A-63-148251 is described. I have. U.S. Pat. No. 4,938,994 also discloses a method of forming a connection bead by generating a pulse with respect to a short sheet-like substrate. Further, Japanese Patent Application Laid-Open No. Hei 8-229497 discloses that, at a start position, the coating is temporarily stopped, a coating bead is formed over the entire coating width, and then moved at a constant speed to form a uniform coating film. A method is disclosed in which the supply of paint is stopped, squeegee coating is performed, and after the stop, excess paint is suctioned and collected.

However, even when any of the above methods is adopted, both the film thickness distribution in the coating direction and the film thickness distribution in the width direction, which is a direction substantially perpendicular to the coating direction, are uniformly and stably maintained immediately after the start of coating. It was difficult to make them compatible so that they could be applied.

In particular, in the method disclosed in Japanese Patent Application Laid-Open No. Hei 8-229497, the size of a bead in a steady state is small, and the size of a bead required to form a paint bead over the entire coating width at a start position is large. They cannot be the same. In addition, since the stationary state cannot be instantaneously changed from the stopped state to a steady (constant speed) state, a uniform film thickness cannot be formed. Further, if the supply of the paint is stopped in the vicinity of the stop, the size of the bead cannot be kept uniform, and the film thickness gradually decreases, or the bead breaks and uncoated streaks occur. Unless thinning or breakage occurs, the bead at the time of stop is larger than that at the time of steady state, and uniformity of the film thickness cannot be obtained even if the bead is collected by suction.

Further, in any of the methods disclosed in the prior art,
There is no disclosure of loss of paint due to preliminary discharge immediately before the start of coating and cleaning of the head lip, and there is a problem in terms of economy.

The present invention has been made in order to solve the above-mentioned problems, and is supplied in a single-wafer system without impairing the features of the die coater such as economy, high-precision thin-film coating property, and paint sealing property. An object of the present invention is to provide a coating apparatus capable of stably forming a coating film having a uniform film thickness on a material to be coated, and a coating method using the same.

[0016]

The condition of the paint bead required for uniform and stable coating by the above-mentioned bead method is defined by the force for fixing the paint bead between the paint discharger and the material to be coated. The power to take away is in a state of being exactly balanced. The former force may be, for example, a surface tension that forms a meniscus, and the latter force may be a shear force accompanying the movement of the material to be coated. Therefore, the shape of the bead in the stable state depends on the paint discharge speed, coating speed,
Base specifications, clearance coating conditions, viscosity, specific gravity,
It is uniquely determined by the physical properties of the paint such as surface tension, the coating environment such as temperature, etc., and even if the bead is temporarily disturbed by external factors etc., the stable state is maintained by self-repair. It is a kind of thing.

[0017] Therefore, when applying using this bead, the application conditions such as the discharge speed, the application speed, and the clearance must be constantly and stably controlled. However, it is not possible to eliminate variations in clearance due to discharge ON / OFF, acceleration / deceleration of speed, variation in substrate thickness, etc., as in the case of single-wafer coating.

Therefore, the present inventor has conducted studies in consideration of the above, and as a result, has found a transfer coating system that utilizes the characteristics of a die coater without using this bead, and has reached the present invention described below.

That is, in the coating apparatus of the present invention, while the paint is supplied to the paint discharge head by the paint supply device, at least one of the stage holding the material to be coated or the paint discharge head is relatively moved. A coating apparatus used in a single-wafer coating method for forming a coating film on a surface of a material to be coated, wherein a slit for discharging a coating material and a slit for collecting a coating material are disposed on the coating material discharging head, and one end of each slit is provided. It is characterized in that the rod bars are arranged.

The coating apparatus of the present invention has a further feature that "the distance between the rod bar and the recovery side of the paint discharge head (entrance gap) is larger than the distance between the rod bar and the discharge side of the paint discharge head (outlet gap). "It is wide", "The distance between the paint discharge head and the rod bar located between the paint discharge slit and the paint recovery slit is the distance where the paint cannot pass." Are connected "and" the paint supply device, the paint discharge head, and the paint recovery device constitute a paint circulation path ".

The coating method according to the present invention is characterized in that single-wafer coating is performed using the coating apparatus according to the present invention.

A further feature of the coating method of the present invention is that "the amount of paint supplied from the paint supply device through the paint discharge slit is used to determine the relative speed between the paint discharge head and the material to be coated. Discharge to the rod bar rotating at a peripheral speed equal to, and transfer and coat the coating film formed on the rod bar to the surface of the material to be coated through an exit gap equal to the gap of the paint discharge slit. '' The relative speed between the stage holding the material to be coated and the paint discharge head is applied at the same speed in the coating start part and the coating end part as in the steady part. " Make the rotation direction the same as that of the work material side "and" The amount of paint supplied from the paint supply device through the paint discharge slit is used to determine the relative speed between the paint discharge head and the workpiece. At the same peripheral speed Discharging the rolling to have rod bar,
When the coating film formed on the rod bar is not transferred onto the surface of the workpiece through the exit gap equal to the gap of the paint discharge slit, the paint is collected by the paint collection slit through the entrance gap. That, "All the paint that was not transferred and applied is collected by the paint collection slit."
That is, including.

[0023]

According to the present invention, the amount required for forming the coating film is discharged from the slit for discharging the paint to the rod bar which is constantly rotating at a peripheral speed equal to the relative speed between the paint discharge head and the material to be coated. To form a coating film. The formed coating film exits the paint discharge head through the exit gap by the rotation of the rod bar. The coating film coming out of the paint discharge head comes into contact with the surface of the material to be coated, and is then transferred and applied. When the coating film formed on the rod bar is not transferred onto the surface of the material to be coated, the coating material returns to the head via the entrance gap by the rotation of the rod bar, and is collected by suction of the coating material slit.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 2 is a schematic view showing an example of a coating apparatus in which the single-wafer coating method of the present invention is performed. This coating device is connected to a metering pump 9 (corresponding to a paint supply device) from a paint tank 14 via a discharge pipe 11, and is further connected to the paint discharge head 1 via the discharge pipe 11. Connected to slit. Further, it is connected to a metering pump 10 via a collection pipe 12 from a paint collection slit of the paint discharge head 1, and further connected to a paint tank 14 via a filter 13. Except for the amount of paint applied to the substrate 5 (corresponding to the material to be coated), the paint circulates through this piping path.

In the paint tank 14, viscosity adjustment and solid content adjustment are performed while stirring or the like to keep a constant paint state. At this time, a solvent or a solid content is added as necessary. Further, in the case of a dispersion type paint, an in-line type disperser, for example, a fluid collision type (ultimizer) disperser can be connected to a piping system to maintain a certain degree of dispersion.

The metering pumps 9 and 10 are syringe pumps,
It is a positive displacement pump such as a gear pump and a diaphragm pump, and is preferably a multi-unit pump for performing continuous discharge and continuous recovery. Further, the recovery pump 10 is preferably one that can recover even if air is sucked in the middle, and it is preferable to provide an air vent valve or the like in this recovery piping system.

The filter 13 is selected in consideration of the type of the coating solvent, the viscosity of the coating, and the like. This filter is also preferably connected continuously for continuous operation.

The uniformity of the coating film formed on the rod bar of the paint discharge head 1 depends on the gap between the discharge slits 2 of the paint discharge head 1 shown in FIG. It is determined by the interval (exit gap 4), the discharge amount, the relative speed of the substrate 5 and the head 1 (the peripheral speed of the rod bar 3), and the like. In particular, the discharge amount and the relative speed between the substrate 5 and the head 1 (the peripheral speed of the rod bar 3) greatly affect the control and uniformity of the film thickness, and the gap between the discharge slits 2 and the outlet gap 4 change the viscosity and solid content of the paint. Etc. are changed for the difference. For example, in the case of a paint of about 10 to 50 CPS, the interval between the discharge slits 2 and the outlet gap 4 need to be about 300 μm.

If the diameter of the rod bar 3 is too small, it is difficult to form a uniform film thickness, and if the diameter is too large, the apparatus becomes larger. Therefore, the diameter of the rod bar 3 may be about 3 mm to 150 mm, and preferably 5 mm to 15 mm, depending on the viscosity of the paint, the required film thickness, and the application width.
mm.

The distance between the rod bar 3 and the collecting side of the head 1 (inlet gap 6) is preferably wider than the outlet gap 4, so that the paint can be collected efficiently and the paint properties can be stabilized by the circulation of the paint. Is obtained.
Further, the interval between the outlet gap 4 and the inlet gap 6 depends on the rotation speed of the rod bar 3, but it is necessary to make the paint as narrow as possible so as not to contact the atmosphere.

The paint discharge head portion and the rod bar 3 located between the paint discharge slit 2 and the paint recovery slit 8
Is preferably an interval at which the paint cannot pass. This makes it possible to completely collect the paint that has not been applied.

Although the distance between the rod bar 3 of the head 1 and the substrate 5 cannot be specified unconditionally, either constant pressure control or quantitative control may be used.

The constant pressure control is suitable for the case where the interval between the rod bar 3 and the substrate 5 is almost zero as in the case of applying a low-viscosity paint. For example, the direction in which the coating proceeds and the direction in which the rod bar 3 rotates on the substrate side are changed. It is preferable in the case of the same direction.

In the quantitative control, a head (not shown) holding the substrate 5 and the head 1 are relatively moved while measuring the distance from the substrate 5 using a non-contact type length measuring device such as a laser focus displacement meter. . At this time, there is a method of moving the stage or the head 1 up and down in order to keep a constant interval. The thickness variation of the glass substrate has almost no wavy variation and a linear thickness gradient, so that even with such a method, a sufficiently constant distance can be maintained.

[0036]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Example 1) An acrylic polymer was dissolved in NMP, and the solid concentration by weight was 12 wt% and the viscosity was 20 CPS.
Transparent paint of 360 mm x 465 mm x 0.7 mm non-alkali glass substrate 1737 (Corning Co., Ltd.)
Was applied.

The paint discharge head has a configuration as shown in FIG. 1, wherein the diameter of the rod bar 3 is 50 mm, the width of the discharge slit 2 is 50 μm, the width of the recovery slit 8 is 50 μm, and the width of the outlet gap 4 is 50 μm. The width of the inlet gap 6 was 70 μm. SUS303 was used for the liquid contact surfaces such as these slits and gaps, and the surface roughness (Rz) was 1.6 μm. The width of the discharge slit 2 and the exit gap 4 was 350 mm, and the width of the recovery slit 8 and the entrance gap 6 was 358 mm. further,
Between the discharge slit 2 and the recovery slit 8, the portion of the discharge slit on the rear side in the rotation direction of the rod bar contacts the rod bar and the head to such an extent that the rotation is not hindered. Fixed.

The application conditions are as follows: the relative speed between the paint discharge head 1 and the substrate 5 is 12 mm / s, and the peripheral speed of the rod bar 3 is 12
mm / s, and the distance (clearance) between the rod bar 3 and the substrate 5 was 40 μm.

The paint was supplied at a discharge rate of 210 μl / s using a precision diaphragm pump manufactured by Millipore. The collection was performed using a tube-type liquid feed pump, and the
μl / s or more. A 0.3 μm filter was installed in the recovery system, and the paint tank was stirred with a magnetic stirrer.

In this embodiment, the coating step shown in FIG. 3 was performed by moving the stage holding the substrate 5.

First, the supply and recovery of the paint are started, and the rod bar 3 is rotated at a constant speed to create a steady state in which a uniform coating film is formed on the rod bar surface (FIG. 3A).

Next, the substrate 5 fixed on a stage (not shown) is moved at a constant speed, and the head 1 is lowered to a position having a clearance of 40 μm when it reaches the coating start portion (FIG. 3).
(B)).

The stage moves as it is, and the paint is transferred to the glass substrate 5 by a slight contact (FIG. 3C).

When the head 1 is lifted when it comes to the application end portion, the transfer of the paint ends (FIG. 3D).

The stage then stops. The supply and recovery of the paint and the rotation of the rod bar are continued, and the next application is awaited.

The coated substrate was dried and formed into a film in an oven at 90 ° C., and the film thickness was measured by a contact-type roughness meter (α step manufactured by Tencor Corporation). The variation at 20 points within the plane excluding the peripheral 1 mm was within 5%.

(Example 2) In the same manner as in Example 1, coating was continuously performed on 100 sheets.

The paint tank uses 12 liters, and the initial 10 liters
Of paint. At the 100th sheet, the remaining amount is 9.12 l,
The solid concentration was 12.6%. In the meantime, maintenance such as cleaning of the head was not performed.

The use efficiency of the paint is as follows.
If the size is × 455 mm, the required amount is 796.25 ml. If the increase in solid content is volatilization of the solvent, the volatilization amount is 80 ml. Therefore, the actual use amount is 800 ml, and the use efficiency is 9%.
It became 9.53%.

The film thickness was measured in the same manner as in Example 1. The film thickness is a total of 11 for the 1st sheet and 10.20.30 ... 100th sheet
When the average film thickness of the sheets was plotted, the inclination was about 1%, which was almost the same as the increase in the solid content concentration. The average film thickness of these 11 sheets was 6.3 μm, and the in-plane variation of each sample was all within 5%.

(Embodiment 3) In the same paint, glass substrate and coating apparatus as in Embodiment 1, the discharge rate was 33.6.
μl / s, and the recovery rate was 33.6 μl / s or more. Further, the rotation direction of the rod bar was reverse to that of Example 1, and the head and the glass substrate were almost brought into contact with each other by constant pressure control. The pressure was only the head's own weight (about 10 kg).

The coating process shown in FIG. 4 was performed.

First, the supply and recovery of the paint are started, and the rod bar 3 is rotated at a constant speed to create a steady state in which a uniform coating film is formed on the rod bar surface (FIG. 4A).

Next, the glass substrate 5 fixed on a stage (not shown) is moved at a constant speed (FIG. 4B). At this time,
The clearance between the head and the glass substrate is set to 100 μm or less in advance so as not to damage the glass substrate when the head 1 is lowered, and the head is lowered when it reaches the coating start portion.

The stage moves as it is, and the rod bar 3
Is transferred to the glass substrate 5 (FIG. 4).
(C)).

When the head 1 is lifted when it comes to the application end portion, the transfer of the paint ends (FIG. 4D). The stage then stops. The supply and recovery of the paint and the rotation of the rod bar continue, and wait for the next application.

The coated substrate is dried and formed in a 90 ° C. oven.

The film thickness was about 1 μm measured by a contact roughness meter (α step manufactured by Tencor Corporation). The variation at 20 points within the plane excluding the peripheral 1 mm was within 5%.

Comparative Example 1 A commercially available die coater (slot coater, Hirata Kiko) shown in FIG. 5 was used to apply the same paint and glass substrate as in Example 3 to obtain a similar film thickness. Done.

As shown in FIG. 5, the head 1 has only the supply slit 2 and has no recovery slit or recovery system.
The pump 9 is a constant-pressure pump and has a suck-back mechanism.

The head 1 descends from above the stationary substrate 5 at the coating start position, and determines the clearance. Thereafter, a paint is supplied from the pump 9 and a liquid is discharged from the slit 2 to form a bead between the lip and the substrate. After the minimum required bead formation, the head and the substrate move relative to each other (substrate movement in this example). Discharge of the coating material is stopped just before the application end position, and then the movement of the substrate is stopped. The excess bead is absorbed into the slit 2 by suck-back to prevent thick coating at the application end portion. In this state, wait for the next coating.

As a result, since the constant pressure pump was used, it was difficult to control the shape of the bead, the initial bead became excessive, and the film thickness at the coating start portion rose. At the end of coating, a stable film thickness could not be obtained due to poor response due to pressure loss and the like. In addition, when continuous application was performed without maintenance due to the influence of paint adhered to the vicinity of the head lip due to excessive beads, streaks were generated.

Comparative Example 2 A commercially available die coater (extrusion coater, FA) shown in FIG.
In S), the same paint and glass substrate as in Example 3 were used to perform coating to obtain the same film thickness.

As shown in FIG. 6, the head 1 has only the supply slit 2 and no recovery slit or recovery system.
The pumps 19 and 20 are quantitative precision pumps, and are provided with a priming device 18 for head cleaning (a mechanism for applying a small diameter roll in advance to obtain a stable lip and a discharge state, and then applying it to a substrate).

The head 1 rises to a stable state by the priming device 18 and descends from the stationary substrate 5 at the coating start position to determine a clearance. At this time, steady discharge is continued. Thereafter, a bead is formed between the lip and the substrate by the liquid discharged from the slit 2. After the minimum required bead formation, the head and the substrate move relative to each other (substrate movement in this example). The discharge of the paint is stopped just before the application end position, and then the movement of the substrate is stopped. In this state, wait for the next coating.

As a result, since the metering pump is used, the bead shape control accuracy is good and the initial bead can be controlled to a minimum. However, there is a difference between the initial bead and the steady bead, and the film thickness at the coating start part is small. There was a little climax. In the coating end portion, the ejection can be stopped with good response, but as in the coating start portion, there is a difference between the bead at the time of the stop and the bead at the time of the steady state, and the film thickness at the coating end portion is slightly raised. Further, since the influence of the paint adhered to the vicinity of the head lip by the bead is maintained by the priming device, the use efficiency of the paint is about 80%.

[0068]

As described above, according to the coating apparatus and the coating method of the present invention, it is possible to obtain the stability of the film thickness by the continuous discharge of the paint and the uniformity of the film thickness by the transfer method without forming beads. There is an effect that can be.

In particular, the gap (entrance gap) between the rod bar and the collection side of the paint discharge head is wider than the gap (exit gap) between the rod bar and the discharge side of the paint discharge head. When the coating film is not transferred onto the surface of the material to be coated, paint is collected through the slit for collecting paint through the entrance gap to obtain film thickness stability and prevent paint deterioration due to continuous discharge of paint. Can be.

In particular, the space between the paint discharge head portion and the rod bar, which is located between the paint discharge slit and the paint recovery slit, is set to a narrow space through which the paint cannot pass, so that unused paint can be completely recovered. be able to.

In particular, by connecting a paint collecting device to the paint collecting slit, it is possible to improve the paint use efficiency by completely collecting unused paint.

In particular, the relative speed between the stage for holding the material to be coated and the coating material discharge head is also set at the same speed in the coating start portion and the coating end portion as in the steady portion, so that the coating material is coated. There is no change in the discharge rate and no change in the relative moving speed of the substrate, and the stability of the film thickness can be always obtained in a stable state.

Further, in particular, by setting the direction of the coating to be the same as the direction of rotation of the rod bar on the side of the material to be coated,
A low-viscosity paint can be applied more stably.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view illustrating an example of a paint discharge head that best illustrates the features of the present invention.

FIG. 2 is a schematic view showing an example of a coating apparatus according to the present invention.

FIG. 3 is a schematic diagram illustrating a coating operation according to the first embodiment.

FIG. 4 is a schematic view illustrating a coating operation according to a third embodiment.

FIG. 5 is a schematic view showing a coating apparatus according to Comparative Example 1.

FIG. 6 is a schematic view showing a coating apparatus according to Comparative Example 2.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Head 2 Slit for discharge 3 Rod bar 4 Exit gap 5 Substrate 6 Inlet gap 7 Gap between head part and rod bar located between discharge slit and collection slit 8 Collection slit 9 Discharge metering pump 10 Collection constant Pump 11 Discharge system 12 Recovery system 13 Filter 14 Paint tank 15 Stirring 16 Paint 17 Pressurized air 18 Priming device 19, 20 Metering pump

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Riko Midorikawa 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 4D075 AC53 AC65 AC73 AC84 AC94 CA48 DA06 DB13 DC24 4F041 AA05 AA12 CA02 CA16 CA28 4F042 AA02 AA06 BA04 BA05 BA12 BA25 CB05 CB11 CC07

Claims (11)

[Claims] A coating material is supplied to a coating material discharge head by a coating material supply device, and at least one of a stage for holding the material to be coated and a coating material discharging head is relatively moved to coat the coating material surface. What is claimed is: 1. A coating apparatus used in a single-wafer coating method for forming a film, wherein a coating discharge slit and a coating recovery slit are arranged on the coating discharge head, and one rod bar is disposed at the tip of each slit. Characteristic coating equipment. 2. The gap (inlet gap) between the rod bar and the collection side of the paint discharge head is wider than the gap (outlet gap) between the rod bar and the discharge side of the paint discharge head. Coating equipment. 3. The gap between the paint discharge head portion and the rod bar, which is located between the paint discharge slit and the paint recovery slit, is a distance at which the paint cannot pass. Coating equipment. 4. The coating apparatus according to claim 1, wherein a paint collection device is connected to the paint collection slit. 5. The coating device according to claim 1, wherein the coating material supply device, the coating material discharge head, and the coating material collecting device constitute a coating material circulation path. 6. A coating method comprising performing single-wafer coating using the coating apparatus according to claim 1. 7. A paint supply slit is applied to a rod bar rotating at a peripheral speed equal to a relative speed between a paint discharge head and a material to be coated, by applying a quantity of paint supplied from a paint supply device through a paint discharge slit. 7. The coating method according to claim 6, wherein the coating formed on the rod bar is transferred onto the surface of the material to be coated via an outlet gap equal to the gap of the slit for discharging and discharging the paint. . 8. The coating method according to claim 1, wherein the relative speed between the stage holding the material to be coated and the coating material discharge head is the same at the coating start portion and at the coating end portion as at the steady portion. 8. The coating method according to 6 or 7. 9. The coating method according to claim 6, wherein the direction in which the coating proceeds and the direction in which the rod bar rotates on the workpiece are the same. 10. A paint supply slit is supplied from a paint discharge slit to a rod bar rotating at a peripheral speed equal to a relative speed of a paint discharge head and a material to be coated, in an amount necessary for forming a coating film. When the coating formed on the rod bar is not transferred and applied to the surface of the material to be coated through an exit gap equal to the gap of the slit for discharging and discharging the paint, the paint is collected by the slit for collecting paint through the entrance gap. The coating method according to any one of claims 6 to 9, wherein the coating is performed. 11. The coating method according to claim 6, wherein all the paint not transferred and applied is collected by a paint collecting slit.