JP3413467B2 - Coating method and coating device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method, generally called dip coating, in which a long or sheet-shaped substrate is once dipped in a coating solution and then coated on both sides of the substrate which is pulled up at a constant speed. The dip coating method is used to coat the surface of plastic film, paper, etc., and is also used to coat the metal plate and glass surface with a photosensitive liquid in the manufacturing process of shadow masks, LCD color filters, etc. .

[0002]

2. Description of the Related Art Conventionally, when the dip coating method is used, the film thickness is determined by the viscosity of the coating solution and the pulling rate of the base material. The higher the pulling rate and the higher the viscosity of the coating solution, the better the film thickness. The film thickness is increased.
That is, since the film thickness is formed while the liquid drips, it becomes thin when the liquid is pulled up slowly and becomes thick when it is pulled up quickly. However, the pulling speed of the base material is related to the uniformity of the coated surface, and if the pulling speed is fast, it will not be uniform due to the swinging of the device, and the speed cannot be increased so much particularly for those requiring uniformity.

Further, in the case of coating on a long base material, the speed is generally limited by the problem of the process before and after the coating process, for example, the limit of the drying furnace of the drying process, etc. The pulling speed is usually constant. Therefore, the film thickness control or adjustment is usually performed by adjusting the viscosity of the coating liquid.

This coating method has a merit that the coating speed is considerably slower than other coating methods such as a roll coating method and a curtain flow method, but it has the advantage that both surfaces can be coated at the same time. In terms of size,
This is one of the best methods.

However, the dip coating method has several problems. First, it takes time to adjust the film thickness. As described above, the viscosity is adjusted in order to adjust the film thickness. There are two methods of changing the temperature of the coating liquid and the concentration of the coating liquid (amount of solvent). Whichever method is used, it takes time to uniformly stabilize the inside of the coating liquid tank after changing the viscosity.
For example, when trying to change the film thickness during continuous coating on a long base material, the longer the time until the viscosity stabilizes, the larger the material loss.

Secondly, the change in film thickness over time is large. Since the dip coating method uses a coating liquid tank, it is unavoidable that the viscosity of the coating liquid changes with time due to evaporation of the solvent from the surface of the coating liquid tank. Especially when the temperature of the coating liquid is high, the viscosity is likely to change greatly. For this reason, normally, the viscosity is controlled by attaching a coating liquid tank to the coating liquid tank, circulating the coating liquid, and attaching a viscosity adjuster to the coating liquid tank. Since it takes time, the response is poor and the viscosity fluctuates within a certain range, so the film thickness also changes accordingly.

Thirdly, it is difficult to make a difference in film thickness between the front and back. When the dip coating method is used, the thickness of the coating film on the front and back of the substrate is the same. However, in some applications, it may be more convenient to have a film thickness difference between the front and back. For example, in the case of applying a photosensitive solution to a metal plate in the manufacture of a shadow mask, the sizes of the patterns on the front and back sides are different, but generally the thinner the film thickness, the better the resolution of the pattern, but the poorer the etching resistance. , It is ideal to apply a thick film on the side with a large pattern that needs to be deeply etched and a thin film on the side with a small pattern, but under the present circumstances, prioritize etching resistance. However, the resolution is not good because both sides are coated thickly.

[0008]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above problems, and shortens the time for adjusting the film thickness, reduces the change in film thickness over time, and imparts a difference in film thickness between the front and back sides. To provide a coating method and a coating device that enable the above.

[0009]

According to the present invention, a long or single substrate 1 is once dipped in a coating solution 2 and then pulled up at a constant speed to apply the coating solution 2 on the surface of the substrate 1. In this method, a plate-like shield 3 for controlling the flow of the coating liquid 2 is applied to both sides of the base material 1 in parallel with the base material 1 at regular intervals with respect to the base material 1 to be pulled up. Installed in liquid tank 4,
This is a coating method in which the positions of the base material 1 and the plate-shaped shield 3 are individually changed on both sides of the base material to individually adjust the coating film thickness on both surfaces of the base material.

The shield 3 is plate-shaped and is effective for a coating method in which the shield 3 is installed parallel to the substrate 1. Further, it is a coating method for further reducing the fluctuation of the film thickness by sending the above-mentioned pulled-up coating film thickness detection signal on the substrate 1 to the shield position control device. In each of the above coating methods, the target substrate 1 is a shadow mask material or a lead frame material.

Next, according to the present invention, an apparatus for carrying out the above-mentioned coating method, that is, a long or sheet-shaped substrate 1 is once dipped in the coating solution 2 and then pulled up at a constant speed. An apparatus for applying the coating liquid 2 on the surface of the material 1, and a position adjusting means for changing the positions of the shield 3 and the shield 3 provided so that the distance to the substrate 1 to be pulled up can be adjusted. It is a coating apparatus comprising. Furthermore, a film thickness detector that detects the coating film thickness on the substrate 1 that has been pulled up, and a shield position control device that drives position adjusting means for the substrate 1 and the shield 3 by the detection signal of the film thickness detector. It is a coating device in which and are connected in series.

Next, the present invention will be described with reference to the drawings. Figure 3
4 and FIG. 4 are diagrams for explaining the arrangement of the main parts when the present invention is applied to a single-wafer substrate and a long plate substrate, respectively. In addition, FIG. 5 is an example of the conventional method shown in FIG.
FIG. 5 is a diagram schematically illustrating the flow of the coating liquid in the coating liquid tank according to FIG. 5 (b), which is an example of the method of the present invention. Each drawing of FIG. 6 is an explanatory view of a main part exemplifying the shape and arrangement of the shield, and the shape of the shield 3 can be various shapes such as a roll, a bar, and a grooved roll.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining the concept of the construction in which the present invention is applied to a long plate base material and a film thickness detector and a shield position control device are connected in series. The coating conditions of the examples are shown in Table 1 below.

Table 2 shows the relationship between the distance L (mm) between the substrate 1 and the shield 3 and the film thickness (μm) after drying.

Next, FIG. 2 shows the elapsed time (time) and the film thickness fluctuation amount (μm) during film thickness control by viscosity, and FIG.
Is an example of the conventional method, and FIG. 2 (b) is an example of the method of the present invention. As a film thickness detector, infrared moisture meter IM-35CV model 1900
(Manufactured by Fuji Technica Co., Ltd.) was used. As shown in the figure, the maximum fluctuation amount of the film thickness was about 1.3 μm in the case of the conventional method, while it was within 0.2 μm in the case of the method of the present invention in about 15 hours.

[0016]

EFFECTS OF THE INVENTION According to the present invention, the shield is placed in the coating liquid tank at a distance from the substrate, and the position of the shield is changed to control the flow of the coating liquid in the coating liquid tank. The film thickness can be adjusted with good responsiveness without changing the physical properties of the coating liquid. In addition, by providing shields on both sides of the base material, it is possible to individually control the film thickness on both sides of the base material. Furthermore, by combining with a film thickness detector, automatic control with good response can be performed so that the film thickness is always constant.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a configuration concept in which the present invention is applied to a long plate base material and a film thickness detector and a shield position control device are connected in series.

FIG. 2 is a diagram showing a relationship between a lapse of time and an amount of film thickness variation in an example of a conventional method and an example of the method of the present invention.

FIG. 3 is a diagram illustrating an arrangement of main parts when the present invention is applied to a single-wafer base material.

FIG. 4 is a diagram illustrating an arrangement of main parts when the present invention is applied to a long plate base material.

FIG. 5 is a side view schematically illustrating the flow of the coating liquid in the coating liquid tank according to the conventional method and the example of the present invention.

FIG. 6 is an explanatory diagram of a main part illustrating the shape and arrangement of the shield.

[Explanation of symbols]

1 base material 2 coating liquid 3 Shield 4 coating liquid tank L Distance between base material and shield

Claims (5)

(57) [Claims] 1. A coating solution (2) is applied to the surface of a substrate (1) by once immersing a long or sheet-shaped substrate (1) in the coating solution (2) and then pulling it up at a constant speed. The method of controlling the flow of the coating liquid (2) on both sides of the base material (1) parallel to the base material (1) at regular intervals with respect to the base material (1) to be pulled up. The plate-shaped shield (3) is installed in the coating liquid tank (4), and the positions of the base material (1) and the plate-shaped shield (3) are individually changed on both sides of the base material. A coating method that individually adjusts the coating thickness on both sides of the material. 2. A coating film thickness detection signal on the pulled-up base material (1) is sent to a shield position control device, and the positions of the base material (1) and the plate-shaped shield (3) are changed to the position of the base material. The coating method according to claim 1, wherein the coating film thicknesses on both surfaces of the base material are individually adjusted by individually changing both sides. 3. The coating method according to claim 1, wherein the base material (1) is a shadow mask material or a lead frame material. 4. An apparatus used in the coating method according to any one of claims 1 to 3, wherein a plate for controlling the flow of the coating liquid (2) is provided on both sides of the substrate (1) to be pulled up and in parallel with the substrate (1). A shield (3) in the shape of a strip so that the distance to the substrate (1) can be adjusted,
The positions of the base material (1) and the plate-shaped shield (3) are set to the base material (1).
A coating device comprising position adjusting means for individually changing both sides of the. 5. A film thickness detector for detecting a coating film thickness on the pulled up substrate (1), and a substrate (1) and a plate-shaped shield (3) according to a detection signal of the film thickness detector. The coating apparatus according to claim 5, further comprising a shield position control device that drives the position adjusting means.