JPH10202156A - Roll coater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce damage caused by a contact with a base on the peripheral face of a coating roll by forming the outer diameter of the center part of the coating roll smaller than the outer diameter of both end parts of the coating roll, in a roll coater equipped with an offset roll to transfer a coating liquid to the coating roll. SOLUTION: The roller coater is operated in such a manner that a coating liquid is transferred to the surface of a base W from the peripheral face of a coating roll 12 (hereafter called 'roll') by brining the surface of the base W into contact with the peripheral surface of the roll 12 after conveying the base W retained on the upper face of a stage 10. In this case, the roll 12 is formed as a reverse camber roll in such a way that the outer diameter D1 of the center part is smaller than the outer diameter D2 of both end parts. Thus it is possible to offset the displacement of the roll 12 from the center part to the lower part when the roll 12 becomes deflected due to the forcing of an offset roll 14 with a difference in the outer diameter between the center part and both end parts of the roll 12. Consequently, the peripheral face of the roll 12 can be positively brought into contact with the surface of the base W over the entire length of the peripheral face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
While transporting various substrates such as DP glass substrates, film liquid crystal substrates, image sensor substrates, printed wiring substrates, and semiconductor wafers in the horizontal direction, rotating the coating roll by bringing the peripheral surface of the coating roll into contact with the surface of the substrate The present invention relates to a roll coater for applying a coating liquid, for example, a photoresist liquid, a pigment for a color filter, a polyimide resin, or the like to a surface of a substrate.

[0002]

2. Description of the Related Art As a roll coater of this type, for example, one disclosed in Japanese Utility Model Laid-Open No. 4-99266 is generally known. This roll coater is a so-called reverse coating type roll coater that rotates the coating roll in a direction opposite to the direction in which the substrate is transported.
In this roll coater, the substrate is vacuum-adsorbed onto the surface plate, held integrally, and conveyed in the horizontal direction, while the coating roll disposed above the conveyance path is moved to the lowest point on the surface plate. The substrate is rotated (reverse rotation) in the direction opposite to the substrate transport direction while being lowered to a position where it contacts the surface of the substrate. Then, while the substrate held on the surface plate is in contact with the peripheral surface of the coating roll and is pressed by the peripheral surface of the coating roll, and passes below the coating liquid, the coating liquid supplied to the peripheral surface of the coating roll is discharged. Transferred from the peripheral surface of the coating roll to the surface of the substrate,
A coating film is formed on the surface of the substrate. Further, the outer peripheral surface of the offset roll is in contact with the outer peripheral surface of the coating roll so as to be pressed, and the outer peripheral surface of the offset roll is rotated in the same direction as the rotational direction of the coating roll (reverse rotation). The application liquid held on the surface is transferred to the peripheral surface of the coating roll and supplied.

In the case where a coating film is formed on the surface of a substrate by the roll coater having the above-described configuration, the coating roll is deflected due to the pushing of the offset roll against the coating roll, and the center of the coating roll is compared with both ends. When the coating roll is displaced downward, both ends of the coating roll do not come into contact with the surface of the substrate, and the coating liquid is not transferred to both sides of the substrate surface, resulting in poor coating. Therefore, conventionally, in order to have sufficient rigidity in the coating roll so as not to bend, to increase the diameter of the coating roll,
In consideration of the bending amount of the coating roll, a method of increasing the pushing amount of the coating roll against the substrate has been adopted.

[0004]

However, in the method of increasing the diameter of the coating roll so as not to cause the coating roll to be bent, the roll coater becomes large and the weight of the coating roll increases. And the maintenance work becomes difficult. Also, in the method of increasing the pushing amount of the coating roll against the substrate and bringing the peripheral surface of the coating roll into contact with the surface of the substrate over its entire length,
Since the contact pressure between the coating roll and the substrate increases, there is a problem that the peripheral surface of the coating roll receives much damage from the substrate.

The present invention has been made in view of the above circumstances, and has been made to prevent the bending of the coating roll by increasing the diameter of the coating roll, or to increase the amount of pushing of the coating roll against the substrate. The coating roll can be reliably brought into contact with the surface of the substrate over its entire length without applying such a method as described above, and the coating liquid can be applied well to the entire surface including both sides of the substrate. It is another object of the present invention to provide a roll coater which can avoid an increase in the size of the apparatus and the difficulty of maintenance work, and can reduce damage to the peripheral surface of the coating roll due to contact with the substrate. .

[0006]

According to the present invention, there is provided a substrate transfer means for transferring a substrate in a horizontal direction, and a peripheral surface pressed against the surface of the substrate transferred by the substrate transfer means while rotating in one direction. And a coating roll for transferring the coating solution held on the peripheral surface to the surface of the substrate when contacted with the coating roll. The coating roll was rotated while contacting the peripheral surface of the coating roll so that the peripheral surface was pressed against the peripheral surface of the coating roll. In a roll coater including an offset roll that transfers a coating liquid to the peripheral surface of a coating roll and a coating liquid supply unit that supplies the coating liquid to the peripheral surface of the offset roll, the outer diameter of a central portion of the coating roll is set at both ends. It is characterized in that it is smaller than the outer diameter of the part.

In the roll coater having the above structure, when the offset of the offset roll against the coating roll causes the coating roll to bend, the outer diameter of the central portion of the coating roll is made smaller than the outer diameter of both ends. The amount of downward displacement at the center of the roll and the outer diameter difference between the center and both ends of the coating roll (accurately, １ ／ of the outer diameter difference) are offset,
The side of the coating roll that is in contact with the surface of the substrate becomes linear, and the peripheral surface of the coating roll reliably contacts the surface of the substrate over its entire length.

[0008]

Preferred embodiments of the present invention will be described below with reference to the drawings.

First, an example of the overall configuration of the roll coater will be described with reference to FIG. This roll coater is a reverse coating type roll coater. In this roll coater, a substrate W is held on the upper surface of a stage 10 which is reciprocally movable in the horizontal direction by vacuum suction or the like. The substrate W is fed to a position directly below the coating roll 12 that rotates (reversely rotates) in the direction opposite to the direction in which the substrate W is transported, and the surface of the substrate W contacts the peripheral surface of the coating roll 12 to perform coating. Roll 12
The coating liquid is transferred from the peripheral surface to the surface of the substrate W to form a coating film on the surface of the substrate W.

The coating roll 12 has at least a peripheral surface formed of a rubber material, and a peripheral surface of an offset roll 14 disposed in parallel with the coating roll 12 is in contact with the peripheral surface of the coating roll 12. . The outer peripheral surface of the offset roll 14 comes into contact with the outer peripheral surface of the coating roll 12 so as to be pressed against the outer peripheral surface of the coating roll 12.
4 rotates in the same direction (reverse rotation),
The application liquid held on the peripheral surface of the offset roll 14 is transferred to the peripheral surface of the coating roll 12 and supplied. At least the peripheral surface of the offset roll 14 is formed of a rubber material or a metal material, and the peripheral surface of the pickup roll 16 disposed in parallel with the offset roll 14 contacts the peripheral surface of the offset roll 14. doing. At least the peripheral surface of the pickup roll 16 is formed of a rubber material, is supported in a horizontal posture, and a part of the peripheral surface is immersed in a coating liquid 20, for example, a photoresist liquid contained in a liquid storage tank 18. I have. Then, the pickup roll 16 rotates in one direction to take out the coating liquid 20 from the liquid storage tank 18 and hold the coating liquid 20 on the peripheral surface. The application liquid is transferred and supplied to the peripheral surface of the offset roll 14 rotating in the opposite direction.

In this roll coater, as shown in FIGS. 1 and 2, the outer diameter D1 at the center of the coating roll 12 is smaller than the outer diameter D2 at both ends (D1 <D).
2) It is an inverted crown roll. 1 and 2 (the same applies to FIG. 3), the difference in outer diameter between the central portion and both ends of the coating roll 12 is exaggerated for easy understanding. The dimensional difference between the outer diameter D1 at the center of the coating roll 12 and the outer diameter D2 at both ends is an optimum value based on the calculation of the amount of deflection (the amount of downward displacement at the center) of the coating roll 12 and the structural analysis. Should be obtained. An example of the dimensions of each part of the coating roll 12 is as follows.
00 mm, outer diameter D = 100 to 120 mm, and depression amount d at the center is 50 to 150 μm.

When a coating film is formed on the surface of the substrate W by a roll coater as shown in FIG. 4 provided with a coating roll 12 having a shape as shown in FIGS. The pushing causes the coating roll 12 to bend, and the center portion of the coating roll 12 is slightly displaced downward, for example, about 50 to 150 μm as compared with the both ends. At this time, since the coating roll 12 is an inverted crown roll in which the outer diameter D1 at the center is smaller than the outer diameter D2 at both ends, the amount of downward displacement at the center of the coating roll 12 and the coating roll 12 The depression amount d at the center is offset, and as shown in FIG. 3, the contact surface side of the coating roll 12 with the surface of the substrate W becomes linear, and the peripheral surface of the coating roll 12 extends over the entire length of the surface of the substrate W. Contact with the coating roll 12
Is transferred from the peripheral surface to the entire surface including both sides of the substrate W. Also, for a wide substrate, by setting the difference between the outer diameter at the center of the coating roll and the outer diameter at both ends appropriately, the coating liquid can be spread over the entire surface of the substrate with a small amount of pushing of the coating roll against the substrate. Can be applied.

Here, an example of a method of manufacturing the coating roll 12 will be described. First, rubber is wound around a metal rod or a metal pipe 13 serving as a center. At this time, the depression as shown in FIG. 1 has not yet been formed. Next, the surface of the wound rubber is polished to smooth the surface, and the central portion is further polished to form a recess to obtain the shape shown in FIG.

The present invention can be applied to various types of roll coaters including a coating roll and an offset roll, in addition to the roll coater having the configuration shown in FIG. For example, in the roll coater illustrated in FIG. 5, a backup that supports the substrate W by contacting the back surface of the substrate W and rotates the transport direction of the substrate W to transport the substrate W below the coating roll 22. A plurality of transport rolls 28 are arranged along the transport path of the substrate W on the front side and the opposite side of the coating roll 22 and the backup roll 26 in the transport direction of the substrate W, respectively. ing. Further, at least the peripheral surface is formed of a rubber material or an offset roll 24 formed of a metal material, and at least the peripheral surface of the doctor roll 30 formed of a rubber material is supported in parallel with each other and in a horizontal posture, The peripheral surfaces of the rolls 24 and 30 are brought into contact with each other, and a liquid reservoir 32 for storing the coating liquid 20 is formed on the upper side of the contact portion. 34, the offset roll 24 and the doctor roll 30 are moved in opposite directions to each other and both rolls 2
The coating liquid 20 is supplied from the liquid reservoir 32 to the peripheral surface of the offset roll 24 by rotating the peripheral surface to move downward on the contact sides of the rollers 4 and 30. The coating roll 22 of the roll coater having such a configuration may be formed in a shape as shown in FIGS.

The roll coater shown in FIG. 6 includes a roll-shaped metal doctor 36 made of a metal material and an offset roll 44 made of a metal material or at least a peripheral surface made of a rubber material. The liquid storage section 3 for supporting the coating liquid 20 in parallel with each other and supporting the metal doctor 36 and the offset roll 44 close to each other in the horizontal position, and in the upper portion of the close portion.
8 and a coating liquid supply nozzle 40 above the liquid reservoir 38.
Is provided. And metal doctor 36
By rotating the offset roll 44 so that the circumferential surface moves downward on the side close to the metal doctor 36 in a state where is fixed, the coating liquid 20 accommodated in the liquid reservoir 38 is From the lower part, it flows out by a required amount through a gap between the metal doctor 36 and the offset roll 44, is supplied to the peripheral surface of the offset roll 44, and comes into contact with the peripheral surface of the offset roll 44 from the peripheral surface of the offset roll 44. The coating liquid is transferred and supplied to the peripheral surface of the coating roll 42 that rotates reversely with respect to the offset roll 44. The coating roll 42 of the roll coater having such a configuration is shown in FIGS.
What is necessary is just to form in the shape as shown in FIG.

[0016]

By using the roll coater according to the present invention, it is possible to increase the diameter of the coating roll so as not to cause the coating roll to be bent, or to increase the pushing amount of the coating roll against the substrate. Since the peripheral surface of the coating roll comes into reliable contact with the surface of the substrate over its entire length, it is possible to apply the coating liquid satisfactorily on the entire surface of the substrate, and to increase the size of the roll coater or to reduce the coating roll. The maintenance work does not become difficult due to an increase in weight, and damage to the peripheral surface of the coating roll due to contact with the substrate is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an embodiment of the present invention, in which a coating roll, which is a component of a roll coater, is exaggerated in shape when viewed from the front.

FIG. 2 is a schematic diagram showing an exaggerated front view of the coating roll.

FIG. 3 is a view for explaining the operation of the coating roll shown in FIGS. 1 and 2, and is a schematic view exaggeratingly showing a state in which the offset roll and the substrate are viewed from the front together with the coating roll.

FIG. 4 is a schematic side sectional view showing an example of the overall configuration of a roll coater.

FIG. 5 is a schematic side sectional view showing another example of the overall configuration of the roll coater.

FIG. 6 is a schematic side sectional view showing still another example of the entire configuration of the roll coater.

[Explanation of symbols]

 10 Stage 12, 22, 42 Coating Roll 14, 24, 44 Offset Roll 16 Pickup Roll 18 Reservoir 20 Coating Liquid 26 Backup Roll 28 Transport Roll 30 Doctor Roll 32, 38 Liquid Reservoir 34, 40 Coating Liquid Supply Nozzle 36 Metal Doctor W substrate

Claims (1)

[Claims] 1. A substrate transport means for transporting a substrate in a horizontal direction, and while rotating in one direction, the peripheral surface is brought into contact with the surface of the substrate transported by the substrate transport means so as to be pressed against the peripheral surface. A coating roll for transferring the held coating solution to the surface of the substrate; and a rotating surface which comes into contact with the coating roll so that the circumferential surface is pressed against the circumferential surface of the coating roll, and transfers the coating solution held on the circumferential surface to the circumferential surface of the coating roll. And a coating liquid supply means for supplying a coating liquid to a peripheral surface of the offset roll, wherein an outer diameter of a central portion of the coating roll is smaller than outer diameters of both end portions. Roll coater characterized by the following.