JPH0929149A - Single-wafer coater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a dried film, thin or thick, with good surface smoothness and high precision and without any defect and to coat with high productivity. SOLUTION: This coater is provided with a stage 2 sucking a substrate A on the upper face and moving in the horizontal direction, an applicator roll 2 arranged above the stage 1 and rotating backward with respect to the traveling direction of the substrate A and a metering roll 3 arranged obliquely above and in parallel to the applicator roll 2, with a gap in between and rotating in the same direction as the applicator roll 2, and the space between the rolls 2 and 3 is utilized as a coating soln. B reservoir. The coating soln. B is constantly fluidized in the reservoir and discharged from the gap at a definite rate to form a liq. film on the face of the applicator roll 2 in fixed thickness, and the liq. film on the applicator roll 2 is transferred to the substrate A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for applying a high-viscosity coating liquid onto a substrate such as glass, ceramics or a composite material sheet with high accuracy, and more particularly to a plasma display panel, a fluorescent display tube or the like. Thick film material layer forming process on glass substrate performed during manufacturing, glazing process step on ceramic substrate, thick film material layer forming process on ceramic substrate performed during manufacturing of hybrid integrated circuit, etc. The present invention relates to a single-wafer coating apparatus that can be effectively used for

[0002]

Conventionally, the step of forming a glass paste or a conductor paste as a solid film on one surface of a glass substrate, a ceramic substrate or the like has been performed in various fields. For example, a conductor pattern such as a thermal head or a fluorescent display tube is formed by forming a solid film of a conductor paste and etching this. The thickness of the solid film formed in this case is a relatively thin film of about 2.5 to 10 μm after drying, but in order to obtain a conductor pattern with high resolution by the thick film etching method, the smoothness is high. It is necessary to form a solid film without pinholes. Usually, this solid film is formed by screen printing, and it is devised to promote leveling by using a paste with reduced viscosity and thixotropy, or to avoid pinholes by printing many times, but mesh mesh It was difficult to completely eliminate the effects of clogging and clogging. For this reason, there is a problem that the yield is deteriorated.

On the other hand, in recent years, a barrier of a plasma display panel has been formed by a subtractive method such as sandblasting. In this case, a barrier forming layer having a thickness after drying of 150 to 250 μm is formed. It is necessary to form a solid film. This step is also usually performed by screen printing, but productivity is extremely poor because about 10 times of repeated coating are required to obtain a predetermined film thickness. Further, it is not possible to eliminate the unevenness due to the mesh. Therefore, it may be necessary to perform a step of polishing to make the surface smooth. Therefore,
Instead of repeating screen printing many times, it is also possible to apply a single time using a single-wafer type blade coater or comma coater, but with these coating methods, the liquid on the edge or back side of the substrate to be coated is applied. However, there is a problem in that it cannot be used as a mass-production machine because it is inevitable to adhere.

The present invention has been made in view of such a situation, and an object thereof is to obtain a surface smoothness from a thin film having a film thickness after drying of about 2 μm to an ultra-thick film having a film thickness of about 250 μm. It is intended to provide a single-wafer coating apparatus that can be formed with high precision and no defects and can be coated with high productivity.

[0005]

In order to achieve the above object, a single-wafer coating apparatus of the present invention includes a stage for adsorbing a substrate on its upper surface and moving it horizontally, and a stage arranged above the stage. An applicator roll that transfers a liquid film from the roll surface to the substrate while rotating in the reverse direction with respect to the traveling direction of the substrate, and has a gap parallel to the applicator roll at a position diagonally above the applicator roll. Arranged, comprising a metering roll that forms a liquid film on the roll surface of the applicator roll while rotating in the same direction as the applicator roll, between the roll surface of the applicator roll and the roll surface of the metering roll. The gist of the present invention is that the coating liquid was used as a reservoir for the coating liquid.

It is preferable that at least the surface layer portion of the roll surface of the applicator roll has elasticity. Further, a stepped roll having the same roll surface length is used for each of the applicator roll and the metering roll, and a weir plate for stopping the coating liquid by closely adhering to the boundary end face between the roll surface and the step portion in these stepped rolls. Is preferably provided. Further, a structure is provided in which a sensor for detecting the position of the liquid surface in the liquid reservoir is provided, and a mechanism for supplying a predetermined amount of coating liquid by a signal from the sensor and maintaining a constant amount of the liquid in the liquid reservoir Is preferred. A configuration may be provided in which an elevating mechanism is provided to lower the applicator roll and the metering roll when the moving stage reaches a predetermined position.

[0007]

1 is a schematic view showing the basic structure of a single-wafer coating apparatus according to the present invention, in which the frame is omitted so that the arrangement state of rolls can be seen.

In the figure, reference numeral 1 denotes a horizontally movable stage, which is constructed so that a substrate A placed on its upper surface is vacuum-sucked and fixed. Reference numeral 2 is an applicator roll arranged above the stage 1, and 3 is a metering roll arranged obliquely above the applicator roll 2 in parallel with the applicator roll 2 and with a gap. A space between the roll surface of the roll 2 and the roll surface of the metering roll 3 constitutes a reservoir for the coating liquid B. The applicator roll 2 is configured to rotate in the opposite direction to the traveling direction of the substrate A, and the metering roll 3 is configured to rotate in the same direction as the applicator roll 2. Reference numeral 4 in the drawing denotes a doctor disposed in contact with the metering roll 3, and the coating liquid B
The supply pipe 5 is attached to this doctor 4. The applicator roll 2 has rubber (N
It is preferred to use a BR, for example one wrapped with a hardness of 60 ° or 90 °.

In the above structure, the coating liquid B is supplied from the supply pipe 5 into the liquid reservoir, and the applicator roll 2
When the metallizing roll 3 and the metalling roll 3 respectively rotate, the coating liquid B is constantly flown in the liquid reservoir and is delivered at a constant ratio from the gap between the applicator roll 2 and the metalling roll 3, while the metalling roll 3 The coating liquid B adhered to the roll surface of No. 1 is scraped off by the doctor 4 and returns to the liquid reservoir. By this operation, the applicator roll 2
When a liquid film having a constant film thickness is formed on the roll surface of and the stage 1 with the substrate A sucked and fixed moves in the direction of the arrow in the figure,
The applicator roll 2 transfers the liquid film on the roll surface to the substrate A.

By thus adsorbing and fixing the substrate A on the stage 1 and carrying it, the warpage of the substrate A can be corrected and the coating can be performed. Further, since the coating liquid B in the liquid reservoir constantly flows in the liquid reservoir, even if a coating liquid having a high thixotropic property is used, its viscosity is reduced after coating and the escape of bubbles is promoted. . For this reason, it is possible to avoid the occurrence of craters and cracks due to defective bubble removal. Also,
By using the applicator roll 2 in which rubber is wrapped around and the surface layer portion has elasticity, the roll surface can be brought into close contact with the substrate A to transfer the liquid film, and the influence of unevenness of the plate thickness of the substrate A can be avoided. be able to.

The general shape of the roll R used for the applicator roll 2 and the metering roll 3 is shown in FIG.
Although as shown in FIG. 2B, a stepped roll Ra having step portions b on both right and left sides of the roll surface a as shown in FIG. 2A may be used. In this case, both rolls 2 and 3 having the same roll surface a are used, and as shown in FIGS. 3 and 4, the weir plate 6, the side doctor 7, and the liquid receiving pan 8 are provided on both sides. Deploy. The weir plate 6 is made of a resin plate that conforms to the shape of the step portion b of the applicator roll 2 and the metering roll 3, and both sides of the liquid reservoir are in close contact with the boundary end surface between the roll surface a and the step portion b. Install it so that it closes. The side doctor 7 is attached so that the doctor blade is pressed in parallel to a portion of the boundary end surface between the roll surface a and the stepped portion b without the weir plate 6, and the coating liquid B that cannot be pressed by the weir plate 6.
Scrap it with the side doctor 7. The liquid receiving pan 8 is attached so that the coating liquid B scraped by the side doctor 7 does not drip on the stage 1 or the substrate A. With this configuration, it is possible to prevent the liquid from dripping from the end surface of the roll and to perform good coating on both ends of the coating surface, and thus to perform coating with selectivity in the width direction. Moreover, the film quality of the liquid film formed on the applicator roll 2 is affected by the amount of liquid in the liquid reservoir, but in order to prevent this, the weir plate 6 is provided, and
A sensor for detecting the position of the liquid surface of the liquid reservoir is attached to the dam plate 6, and when the amount of the coating liquid B in the liquid reservoir falls below a predetermined amount, the sensor detects this and supplies the coating liquid B. It is preferable that the pipe 5 be automatically supplied.

In the embodiment shown in FIG. 5, the applicator roll 2 and the metering roll 3 are unitized and an elevating mechanism is provided thereto. In this embodiment, application is performed as follows. First, the substrate A is sucked and fixed onto the stage 1 at the position shown in (a), and the stage 1 horizontally moves to the right in this supported state. During this movement, the thickness and length of the substrate A are measured at the sensor 9 in front of the roll unit as shown in (b). As this sensor 9, for example, a laser focus displacement meter is used. Then, when the substrate A enters the coating start point as shown in (c), the roll unit descends to start coating. When the stage 1 further moves and the substrate A reaches the coating end point, as shown in (d), the roll unit moves up to complete the coating. With this configuration, it is possible to perform selective coating in the transport direction of the stage 1. Further, it is possible to prevent the liquid from adhering to the tip edge portion of the substrate A or the stage 1.

[0013]

EXAMPLE In this example, a thick film for forming a barrier for a plasma display panel was formed on a glass substrate by a sandblast method. In addition, here, a coating apparatus having all the configurations described in the above embodiment was used.

As the substrate A, there was used unpolished soda lime glass having a size of 350 × 488 mm and a thickness of 2 mm formed by the float method. This substrate A had a maximum variation in plate thickness of 35 μm. As the coating liquid B, a glass paste for plasma display panel barrier (G3-0414) manufactured by Okuno Chemical Industries, Ltd. was used. The viscosity of this coating solution was 10300 cps as measured by a BL type rotational viscometer (No. 3 rotor, 6 rpm).

Speed of the metering roll 2 0.78 m /
Min., Rotation speed of applicator roll 3 3.37 m /
Min, stage 1 transfer speed 1.51 m / min, applicator roll 2 and metering roll 3 gap 200μ
m, pushing amount of the applicator roll 2 to the substrate A 20
The coating was performed under the condition of -60 μm.

Drying after coating was carried out by using a far-infrared ceramic panel heater and heating at a set temperature of 120 ° C. for 15 minutes and subsequently at a set temperature of 170 ° C. for 10 minutes. As a result, a highly uniform coating film having a film thickness of 160 ± 8 μm was formed in a rectangular region 15 mm inside from the outer edge of the substrate A.

[Brief description of drawings]

FIG. 1 is a schematic view showing a basic configuration of a single-wafer coating apparatus according to the present invention.

FIG. 2 is a diagram showing the shapes of rolls used for an applicator roll and a metering roll.

FIG. 3 is a front view showing a state in which an applicator roll using a stepped roll and a wetting plate are provided with a weir plate.

FIG. 4 is a side view of the same.

FIG. 5 is a view for explaining the operation of the coating apparatus provided with the lifting mechanism.

[Explanation of symbols]

 1 Stage 2 Applicator roll 3 Metering roll 4 Doctor 5 Supply pipe 6 Weir plate 7 Side doctor 8 Liquid receiving pan 9 Sensor A Substrate B Coating liquid

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Sakurako Hatori 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd.

Claims (5)

[Claims] 1. A stage which moves a substrate in a horizontal direction by adsorbing a substrate on an upper surface, and a liquid film which is disposed above the stage and rotates reversely with respect to the traveling direction of the substrate from the roll surface to the substrate. And an applicator roll that transfers the liquid, are arranged in a position diagonally above the applicator roll in parallel with the applicator roll with a gap, and while rotating in the same direction as the applicator roll, a liquid film is formed on the roll surface of the applicator roll. A single-wafer coating apparatus comprising: a metering roll to be formed, wherein a space between the roll surface of the applicator roll and the roll surface of the metering roll is used for storing a coating liquid. 2. The single-wafer coating apparatus according to claim 1, wherein at least the surface layer portion of the roll surface of the applicator roll has elasticity. 3. A stepped roll having the same roll surface length is used for each of the applicator roll and the metering roll, and for stopping the coating liquid by closely adhering to the boundary end face between the roll surface and the step portion of these stepped rolls. The single-wafer coating apparatus according to claim 1 or 2, further comprising a weir board. 4. A mechanism for providing a sensor for detecting the position of the liquid surface in the liquid reservoir, supplying a predetermined amount of coating liquid in response to a signal from the sensor, and maintaining a constant amount of the liquid in the liquid reservoir. The single-wafer coating apparatus according to claim 1, wherein the single-wafer coating apparatus is provided. 5. The elevating mechanism for lowering the applicator roll and the metering roll when the moving stage reaches a predetermined position, according to claim 1, 2, 3 or 4. Single-wafer coating device.