JP2000042469A - Coating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a uniformly coated film on a sheet type substrate to be coated, especially such as a large size glass substrate by a method wherein a part to be coated for washing is equipped with a plurality of rotatable rollers and a body to be coated which is conveyed between the rollers by centering an axis extending in the same direction as that of a slit. SOLUTION: A part to be coated for washing 10 is equipped with a sending out roller 21, conveying rollers 22a, 22b, a tension control roller 23, and a winding roller 24 all of which have the same axial direction as an axial direction of a slit 14a of a coating head extending horizontally. Further, a body to be coated 25 which is conveyed between respective rollers of the conveying rollers 22a, 22b, and the tension control roller 23 from a state of being wound on the sending out roller 21 and wound up on the winding roller 24, is provided. The winding roller 24 is enabled to be rotated by a driving part, and the tension control roller 23 is set in a movable state in the arrow direction in order to keep the tension in conveying the body to be coated 25 constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus and, more particularly, to a coating apparatus for uniformly and efficiently applying a coating liquid to a single-wafer type substrate such as a large glass substrate.

[0002]

2. Description of the Related Art In general, a spin coating method is often used as a method of applying a coating liquid to a large glass substrate such as a color filter for an LCD.

[0003] The spin coating method includes an open-air type and a closed cup type, both of which have a low coating efficiency of about 10%, and have a coating film thickness at a rotation center portion and a peripheral portion of a substrate to be coated. Has the disadvantage that it becomes too thick. Therefore, for example, when the coating film thickness is several μm ± 3%
When it is required to be within the range, it is difficult to use the coating film formed by the spin coating method as it is, and the coating film thickness in the intermediate region between the rotation center portion and the peripheral portion of the substrate to be coated is relatively small. It is necessary to use a uniform part.
Therefore, the spin coating method has problems in the amount of the coating liquid used, the effective use of the substrate to be coated, and the like.

[0004] As a method for solving the above-mentioned drawbacks of the spin coating method, there are a knife coating method, a roll coating method and a die coating method.

In each of these methods, a coating clearance is provided on a substrate to be coated, and the coating film thickness is determined by the set value to obtain the smoothness of the coating surface. It is difficult to obtain a uniform film thickness when the smoothness (degree of unevenness) on the surface of the coated substrate is lower than the coating accuracy (the degree of unevenness is large).

A dip coating method is generally known as a coating method of a coating liquid which is hardly affected by irregularities on the surface of a substrate to be coated. In this method, a non-coated portion of the substrate to be coated is coated. It is indispensable and the work becomes complicated.

[0007] In view of the above, a bead coating method capable of solving the above-mentioned drawbacks of the respective coating methods and forming a uniform coating film on a single-wafer substrate in a stable state without being affected by the physical properties of the coating liquid. (Japanese Patent Application No. 6-524109) has been proposed.

In this coating apparatus, a coating head having a linear slit opening upward is provided, and the substrate to be coated sucked by the substrate holder has its tip end immediately above the slit of the coating head via a predetermined clearance. And are positioned to face each other. When the application liquid is supplied to the application head, the application liquid is discharged from the slit to form a bead, and adheres to the lower surface of the front end portion of the substrate to be applied. From this state, the substrate holder is slid obliquely upward at a constant speed, and the coating liquid is sequentially adhered from the beads to the lower surface of the substrate to be coated, forming a layer of the coating liquid. At this time, the application liquid is continuously supplied to the application head, and the amount of the application liquid in the bead is kept constant. As described above, when the substrate to be coated rises obliquely upward and its rear end reaches the slit of the coating head, the slide of the substrate holder is stopped, and the coating liquid for forming the bead is sucked into the coating head and the bead is formed. Be extinguished. This separates the coating head from the coating liquid layer on the substrate to be coated.

[0009]

However, in the coating apparatus of the bead coating method as described above, if the supply of the coating liquid to the coating head is performed only at the time of coating, the time required for coating the substrate to be coated for some reason is reduced. If the interval is long, the coating liquid at the tip of the coating head dries and the viscosity increases, and in the next coating, the coating film made of the high-viscosity coating liquid accumulated at the tip of the coating head and the newly supplied coating There has been a problem that uneven coating and gradation occur at the boundary with the coating film made of a liquid. Further, when dirt is generated due to drying and solidification of the coating liquid at the tip of the coating head, there is also a problem that, in the next coating, stripes occur in the coating direction. In order to solve this problem, when the time interval of coating is long, it is performed to prevent the coating liquid from drying by sealing the tip of the coating head.
Drying of the coating solution cannot be completely suppressed. Therefore, it is necessary to periodically wipe off the application liquid having increased viscosity, or to newly provide a cleaning / drying mechanism for cleaning the application head with the cleaning liquid, which causes a problem that the application apparatus becomes complicated and process management becomes complicated. is there.

The present invention has been made in view of such circumstances, and particularly provides a coating apparatus capable of forming a uniform coating film on a single-wafer-type substrate such as a large glass substrate. The purpose is to do.

[0011]

In order to achieve the above object, the present invention provides a coating head having a band-shaped slit extending in a horizontal direction, and the coating head and a substrate to be coated such that the slit faces the substrate to be coated. A moving means for relatively moving the coating head, a coating liquid supply means for supplying a coating liquid to the coating head, and a cleaning target portion disposed outside a coating operation range on the target substrate by the coating head. And the cleaning target portion includes a plurality of rollers rotatable around an axis extending in the same direction as the slit, and a target object to be conveyed between the rollers.

In the present invention, during the coating operation on the substrate to be coated, the object to be coated in the cleaning target portion is placed between the plurality of rollers outside the range of the operation of coating the substrate by the coating head. While being transported, the coating liquid is moved on the slit of the coating head to perform coating, so that drying of the coating liquid on the coating head is prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below.

FIG. 1 is a side view showing an example of the embodiment of the coating apparatus of the present invention. In FIG. 1, a coating device 1 is attached to a support frame 11A of an apparatus main body 11 in a state where the end portion on the downstream side (in the direction of arrow A in FIG. 1) in the sliding direction at the time of coating is inclined so as to be lower. Guide frame 12, a coating head 14 slidably mounted on the guide frame 12, and a support frame 11A.
A substrate holder 13 rotatably attached to the
A cleaning target portion 10 is disposed immediately above the guide frame 12 and outside the rotation range of the substrate holder 13.
The disposition position of the cleaning application portion 10 is indicated by a solid line in FIG. 1 (indicated by a solid line in FIG. 1). Guide frame 1 than
2 is located at the upper end side (the direction of arrow B in FIG. 1).

The cleaning application section 10 includes a feed roller 21, transport rollers 22a and 22b, and a tension control roller 2 having the same axial direction as the slit 14a of the coating head 14 extending in the horizontal direction.
3. From the state of being wound up by the hoisting roller 24 and the sending-out roller 21, the object 25 to be transported between the conveying rollers 22 a and 22 b and the tension control roller 23 and wound up by the hoisting roller 24.
And The hoisting roller 24 is rotatable by a drive unit (not shown), and the tension control roller 23 is movable in the direction of the arrow in order to maintain a constant tension when the object 25 is transported.

The object 25 to be coated is preferably one whose surface properties are close to those of the substrate S to be coated as described later. A flexible metal film such as a conductive resin film, aluminum, copper, stainless steel, or iron can be used. In addition, the transport speed of the object 25 to be coated in the cleaning target portion 10 can be set as appropriate.
Normally, the speed is set substantially equal to the sliding speed of the coating head 14 with respect to the guide frame 12.

FIG. 2 shows a state in which the coating head 14 is further above the sliding movement range during coating on the guide frame 12 (FIG. 1).
(Indicated by arrow B in FIG. 2) and shows a state in which it is located below a cleaning application target portion 10. As shown in FIG. 2, the cleaning-applied portion 10 includes an elevating device (not shown) that integrally moves up and down the transport rollers 22a and 22b in the direction of arrow a.

The cleaning-applied portion 10 is placed in a state where the coating head 14 is located below the cleaning-applied portion 10.
The transport roller 22 is placed on the coating head 14 by the lifting device.
a and 22b are integrally lowered. As a result, the application object 25 transported between the transport rollers 22a and 22b passes over the bead formed in the slit 14a to perform the application.

Incidentally, the entirety of the above-mentioned cleaning coated portion 10 may be moved up and down with respect to the coating head 14 in the direction of arrow a.

FIG. 3 is a view showing another embodiment of a portion to be coated for cleaning in the coating apparatus of the present invention. In FIG. 3, the application portion for cleaning 10 ′ includes a delivery roller 21 ′, a transport roller 22 ′, and a winding roller 24 ′ having the same axial direction as the axial direction of the slit 14 a of the coating head 14 extending in the horizontal direction. An application target 25 is transported from a state of being wound up by the feed-out roller 21 ′ through a transport roller 22 ′ and wound up by a winding roller 24 ′. The above-mentioned hoisting roller 24 'is rotatable by a drive unit (not shown), and the cleaning-applied part 10'
The whole is raised and lowered in the direction of arrow a with respect to the coating head 14 by a lifting device (not shown).

FIG. 4 is a view showing another embodiment of a portion to be coated for cleaning in the coating apparatus of the present invention. In FIG. 4, a cleaning-applied portion 10 ″ includes a feed roller 21 ″ and a winding roller 2, which have the same axial direction as the axial direction of the slit 14 a of the coating head 14 extending in the horizontal direction.
4 "and an object 25 to be conveyed and wound up by a winding roller 24" from a state of being wound up by a feed roller 21 ". The above-mentioned winding roller 24" can be rotated by a drive unit (not shown). The entirety of the cleaning-applied portion 10 ″ is moved up and down in the direction of arrow a with respect to the application head 14 by an elevating device (not shown).

In the above-described coating apparatus, the cleaning target portion can be moved up and down with respect to the coating head. However, the coating head 14 can be raised and lowered with respect to the cleaning target portion. .

The substrate holder 13 of the above-mentioned coating apparatus 1 is rotated about an axis P extending in the horizontal direction by a drive unit 19 in the directions of arrows a and b in FIG.
The substrate S to be coated is sucked and held on the suction surface by the operation of a suction mechanism (not shown). The substrate holder 13 that holds the substrate S to be coated by suction is positioned between the coating position where the position is regulated by the stopper 18a and the substrate transfer position where the position is regulated by the stopper 18b (shown by a dashed line in FIG. 1). ) Is rotatable.

The coating head 14 discharges a coating liquid supplied from a coating liquid supply means (not shown) upward from the slit 14a. This coating head 14
Are screwed into a ball screw 15 provided along the guide frame 12, and the ball screw 15
As a result, the slit 14 a slides along the guide frame 12 while facing the substrate S to be coated.

Here, an example of the coating head 14 will be described with reference to FIGS.

5 to 8, the main body 14A of the coating head 14 has a length a equal to or larger than the width of the substrate S on which the coating liquid is to be coated. A slit 14a that extends and opens upward is formed. A pair of slopes 14B and 14C are formed on both sides of the slit 14a.

Inside the main body 14A, there is formed a hollow liquid reservoir 14D extending in parallel with the slit 14a and communicating with the slit 14a over the entire area in the axial direction. A coating liquid supply pipe 14E attached to a lower portion of the slit 14a is connected to the liquid reservoir 14D.
The coating liquid introduced from the coating liquid supply pipe 14E is discharged from the slit 14a via the liquid pool 14D.

In the figure, reference numeral 14F denotes a pair of slit length adjusting packings which are detachably fitted to both ends of the slit 14a, respectively, and the slit length adjusting packing 14F is adjusted to have a desired length. The width of the coating liquid discharged from the slit 14a can be adjusted by replacing the packing with the packing.

The following dimensions are given as an example of the dimensions of each part of the coating head 14 shown in FIG.

Length a of main body 14A = 400 mm Width b of main body 14A = 50 mm Height c of main body 14A = 80 mm Length d of slit 14a (width after adjustment by slit length adjusting packing 14F) = 350 mm Slit 14a Width e = 1 mm Depth of slit 14a f = 27 mm Depth g of liquid reservoir 14D g = 40 mm As a coating liquid supply unit for supplying the coating liquid to the coating head 14, a known quantitative liquid supply device can be used. .
Specifically, there is a mechanism as shown in FIG. The coating liquid supply means pushes the coating liquid contained in the tank 30 by air pressure supplied through a valve 31 and supplies the coating liquid into a fixed amount pump 33 through a coarse adjustment needle valve 32. The metering pump 33 has a thin film 34 inside, and the inside is coated with the coating liquid
And the air supply side 33b.
3b includes a pressurized cylinder 3 having a piston 36 therein.
5 is connected. Then, by moving the piston 36 by a predetermined stroke in the direction of the arrow, the inside of the air supply side 33b of the metering pump 33 is pressurized to push up the thin film 34 in the direction of the application liquid supply side 33a. A predetermined amount of the coating liquid is supplied to the coating head 14 via the air operated valve 37 and the suck back valve 38.

The air actuated valve 37 is automatically activated by air pressure when the application of the coating liquid to the substrate S is completed, and stops the supply of the coating liquid to the coating head 14. The suck back valve 38 is supplied to the application head 14 by closing the air-operated valve 37 and causing the piston 38a to slide in the direction of the arrow shown in FIG. 9 to generate a negative pressure in the cylinder 38b. The application liquid is sucked and collected.

Next, the operation of the coating apparatus 1 of the present invention will be described.

First, application is performed on the substrate S by the application head 14 in a state where the substrate holder 13 holding the substrate S by suction is held at the application position indicated by a solid line in FIG. In this application, the application head 14 is moved obliquely downward (in the direction of arrow A in FIG. 1) along the guide frame 12 while supplying the application liquid to the application head 14 at a constant flow rate from the metering pump 33 of the application liquid supply unit. I do. At this time, the supplied coating liquid is discharged from the slit 14a to form a bead, and the bead is formed according to the setting of the clearance between the opening of the slit 14a and the lower surface of the substrate S to be coated held by the substrate holder 13. The coating solution is applied from the bead to the substrate S
Is sequentially applied to the lower surface of the substrate. In this application,
The application liquid is continuously supplied to the application head 14, and the amount of the application liquid in the bead is kept constant.

When the coating head 14 moves along the guide frame 12 and the slit 14a of the coating head 14 reaches the rear end of the substrate S to be coated, the coating head 14 stops sliding and is connected to the coating head 14. The application liquid forming a bead is sucked into the application head 14 by the actuation of the suck back valve 38 and the application head 14
And the coating film on the substrate S to be coated are separated.

When the coating on the substrate S to be coated as described above is completed, the substrate holder 13 is rotated about the axis P (in the direction of the arrow b in FIG. 1) and is regulated to a predetermined substrate transfer position by the stopper 18b. You. At this substrate transfer position, the holding plane of the substrate holder 13 is in a horizontal state, and the suction holding of the substrate S to be coated by the substrate holder 13 is released.
The substrate S on which the coating has been completed is taken out, and a new substrate S is mounted. Then, the substrate holder 13 that has sucked and held the new substrate S is rotated about the axis P (in the direction of the arrow a in FIG. 1), and is regulated to a predetermined coating position by the stopper 18a.

On the other hand, when the coating on the substrate S to be coated is completed, the coating head 14 returns to the coating start position (the position shown by the solid line in FIG. 1) along the guide frame 12, and
Wait for the next application.

By repeating such an operation, coating on the substrate S to be coated can be performed. When the coating interval is extremely short, drying of the coating liquid in the slit 14a of the coating head 14 may cause a problem. Absent.

If the coating interval is longer than the above-described normal coating and the coating liquid may dry in the slit 14 a of the coating head 14, the coating head 14 is moved along the guide frame 12 when the coating liquid is dried. Is moved further upward from the range of the slide movement, and stops below the application target portion 10 for cleaning. Next, the transport rollers 22a and 22b of the cleaning target portion 10 are integrally lowered onto the coating head 14 by the lifting device. The coating liquid is supplied to the coating head 14 from the metering pump 33 of the coating liquid supply means at a constant flow rate to form a bead in the slit 14a, so that the object 25 to be transferred transferred between the transfer rollers 22a and 22b.
Is applied with a coating liquid. As a result, the coating liquid at the tip of the coating head 14 is replaced with the newly supplied coating liquid, and the increase in the viscosity of the coating liquid on the coating head 14 and the occurrence of contamination are prevented.

When the coating is started again from the above state,
The transport rollers 22a and 22b of the cleaning application portion 10 are lifted upward from the application head 14 by an elevating device. Next, the coating head 14 is returned to the coating start position (the position shown by the solid line in FIG. 1) along the guide frame 12, and
Start the next application. In the next coating, coating is performed with a newly supplied coating liquid having a constant viscosity, so that the formed coating film has a uniform thickness. Further, even in the normal coating in which the above-described coating interval is short, the coating is performed on the object 25 of the cleaning target portion 10 every time during the coating operation on the target substrate S, so that the coating is performed more uniformly. It is possible to form a coating film having a small thickness.

The coating liquid used in the coating apparatus of the present invention is not particularly limited. For example, a solvent-based photosensitive resin or an aqueous photosensitive resin having a viscosity of about 4 to 15 cps, or a pigment or the like may be added to these photosensitive resins. Colored photosensitive resin in which a coloring material is dispersed, various adhesives, a resin for forming a protective film, and the like,
Various inks and the like can be targeted.

The substrate to be coated with the coating apparatus of the present invention is not particularly limited. For example, a glass substrate for an LCD color filter or the like has a large area and a low surface smoothness ( Usually 50 to 70 μm, maximum 100
Even if the substrate has irregularities of about μm, a coating film having a uniform thickness can be formed.

In the above-described embodiment, the slit of the coating head is opened upward, and the coating head moves to perform coating with respect to the fixed substrate to be coated. In the embodiment in which the coating head opened upward is fixed and the substrate holder holding the substrate to be coated is moved, the coating head with the slit opened downward is movably disposed above the substrate to be coated. Embodiments and embodiments in which a coating head with a slit opened downward and a substrate holder holding a substrate to be coated may be moved.

Further, in the above-described embodiment, the coating head is further moved from the sliding movement range at the time of coating and is positioned below the cleaning target portion. It may be configured to move to the coating start position of the head.

[0044]

As described in detail above, according to the present invention,
A coating head having a band-shaped slit extending in the horizontal direction, and a moving unit for relatively moving the coating head and the substrate to be coated such that the slit faces the substrate to be coated,
A coating liquid supply means for supplying a coating liquid to the coating head, a plurality of rollers rotatable around an axis extending in the same direction as the slit, and a cleaning coating target portion having a coating target conveyed between these rollers; In a normal application in which the application interval is short, the application liquid is supplied from the application liquid supply unit to the application head during the application in which the application head relatively moves along the substrate to be applied. When the time interval between coatings on the substrate to be coated is long, it is possible to form a coating film with a uniform thickness on the outside of the range of operation of coating on the substrate by the coating head. By performing coating on the object to be coated, the coating liquid at the tip of the coating head is replaced with a newly supplied coating liquid,
The viscosity of the coating solution on the coating head and the occurrence of contamination are prevented, and the next coating is performed with a newly supplied coating solution having a constant viscosity. Becomes uniform, furthermore, even in the ordinary application in which the above-mentioned application interval is short, by performing application to the object to be applied of the cleaning application portion every time during the application operation to the application substrate. Thus, a coating film having a more uniform thickness can be formed.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of an embodiment of a coating apparatus of the present invention.

FIG. 2 is a view for explaining a cleaning application target portion in the coating apparatus of the present invention.

FIG. 3 is a view showing another embodiment of a cleaning application portion in the application apparatus of the present invention.

FIG. 4 is a view showing another embodiment of a cleaning application portion in the application apparatus of the present invention.

FIG. 5 is a perspective view showing an example of a coating head used in the coating device shown in FIG.

FIG. 6 is a front view of the coating head.

FIG. 7 is a plan view of the coating head.

FIG. 8 is a side view of the coating head.

FIG. 9 is a diagram showing an example of a coating liquid supply unit used in the coating device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Coating apparatus 10, 10 ', 10 "... Coating part for washing | cleaning 12 ... Guide frame 13 ... Substrate holder 14 ... Coating head 14a ... Slit 15 ... Ball screw 19 ... Drive part 21, 21', 21" ... Discharge roller 22a, 22b, 22 '... Conveying roller 23 ... Tension control roller 24, 24', 24 "... Winding roller 25 ... Coating object S ... Coating substrate

Claims (1)

[Claims] A coating head having a band-shaped slit extending in a horizontal direction; moving means for relatively moving the coating head and the substrate to be coated such that the slit faces a substrate to be coated; A coating liquid supply unit configured to supply a coating liquid; and a cleaning target portion disposed outside a coating operation range of the coating head on the target substrate, the cleaning target portion being in the same direction as the slit. A coating device, comprising: a plurality of rollers rotatable around an axis extending in a direction extending between the rollers; and an object to be coated conveyed between the rollers.