JPS5973834A - Etching method of shadow mask - Google Patents

Abstract

PURPOSE:To form a resistance layer with no pin hole or buble and bore an electron beam pass hole section with extremely excellent quality by removing a photosensitive film only on one side after the first etching process, forming an etching liquid resistant layer, and etching the other face. CONSTITUTION:Small hole and large hole patterns are formed on both faces of a shadow mask raw material 21, and the first etching is performed until the opening diameter of a small hole section 6 is made D3, and a shallow large hole section 271 is etched from a large hole formation section 25. The face formed with the large hole section 271 is covered with a sheet 31 and a photosensitive film 22 of a small hole section 26 on the opposite face is removed, and an etching liquid resistant layer 28 is formed on the face of the raw material 21 including the inside of the small hole section 26. The second etching forming the large hole section 27 with a diameter D4 is performed, and the resistance layer 28 in the small hole section 26 is exposed to form an electron beam pass hole with a predetermined diamter. The resistance layer 28 and a photosensitive film 23 are removed, and a shadow mask is completed. Accordingly, the defect of the electron beam pass hole section due to a pin hole or a bubble is reduced to nil, and a shadow mask with extremely excellent quality can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a shadow mask used in a color cathode ray tube.

[Technical background of the invention and its problems]

Shadow masks used in color cathode ray tubes are manufactured through the following process.

That is, a process of applying a photosensitive liquid to both main surfaces of the shadow mask material, a drying process of forming the photosensitive liquid into a film to form a photosensitive film, and a process of adhering a negative master plate having a predetermined negative turn to the photosensitive film. a developing process to remove unexposed areas; a burning process to improve the etching liquid resistance of the exposed areas and adhesion to the shadow mask material; and an etching process using the exposed areas as a mask to form electron beam passage holes and parts. The process consists of an etching process for forming a hole, a process for removing the photoresist film to form a flat mask, and a process for forming the flat mask into a shadow mask by press working.

On the other hand, color cathode ray tubes have a wide variety of uses, including for general home use and for monitors and displays.Aside from general home use, color cathode ray tubes for monitors and displays require extremely fine image quality. The electron beam passage hole portion of the shadow mask used for these is required to be highly precise and minute.

Next, a method of manufacturing a shadow mask according to Japanese Patent Publication No. 57-26345, which is the closest conventional method to the method of manufacturing a shadow mask of the present invention, will be explained with reference to FIGS. 1 to 5.

First, a photoresist film (21 (3)) is formed on both main surfaces of a mask material (1) made of a long mild steel plate or an amber plate, and then a negative pattern for large holes and a negative pattern for small holes are formed. The negative original plate is brought into close contact with the photoresist film (2) through an exposure process and a development process, as shown in Figure 1.
The diameter (d,
) and the photoresist film (2) (3) with the large hole forming part (5) are removed, and the photoresist film (2) (3) is photocured except for the small hole forming part (4) and the large hole forming part (5). 3) remain.

Next, as shown in FIG. 2, an etching solution is sprayed onto both main surfaces of the shadow mask material (1) to etch the small holes (6) until the opening diameter becomes (Dl). Of course, in this case, a shallow large hole portion (71) is also etched from the large hole forming portion (5).

Next, as shown in FIG. 3, a resistive layer (8) of etching solution is formed on the photoresist film (2), including inside the small holes (6).

Next, as shown in Fig. 4, the etching liquid is mainly sprayed on the side of the shallow large hole (4,) to reach the resistance layer (8) formed inside the small hole (6) and to completely remove the small hole. The large hole part (7), which has been enlarged without disturbing the opening diameter (Dl) of the part (6), is etched until the opening diameter becomes (D2), and after washing and drying, the resistive layer (8) is formed. and photoresist film (2
) and (3) are removed, and a shadow mask (actually a flat mask) having predetermined electron beam passage holes (9) as shown in FIG. 5 is completed.

According to such a method of manufacturing a shadow mask, the cross-sectional shape of the electron beam passing hole (9) is stabilized, and the small hole (6) is stabilized.
) opening diameter (6 and 9, for example, only has a looseness of 140 Sμm, and the depth of the small hole (6) t) is also stable, and the amount of side etching of the small hole (6) is also about 20 μm. ~30
Although it is said that it is possible to form a good electron beam passage hole (9) as small as μm, in reality, the resistive layer (
8) is formed by a spray method, so that the eaves (21) of the photoresist film (2) that remains after side etching are formed, and the small holes (6) are completely filled with the resistive layer (8). It is difficult to do this and pinholes, bubbles, etc. (It) are likely to occur, and for this reason, when forming the large hole (sword), the etching solution enters the small hole (6) through these pinholes and bubbles, resulting in the formation of electrons. There was a problem in that the beam passage hole (9) was easily defective.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to obtain a shadow mask in which a resistive layer is formed without pinholes or bubbles, and in which electron beam passage holes are formed with extremely high quality. The purpose of the present invention is to provide a method for manufacturing a shadow mask.

[Summary of the invention]

That is, a process of leaving a photoresist film on both main surfaces of the shadow mask material except for the small hole forming part and the large hole forming part, respectively, and etching from either the small hole forming part or the large hole forming part to a desired depth. After the first etching step of forming the first holes, and the washing and drying steps, the step of covering the main surface of the shadow mask material different from the main surface on which the first holes are formed with a sheet with a sheet. , removing the photoresist film of the shadow mask material in which the first hole has been formed, and forming a resistive layer of an etching resistant solution in the first hole and on the shadow mask material; and removing the sheet. a second etching step in which the resistive layer is exposed from the coated main surface through the rev hole forming portion or the large hole forming portion, and is etched to form an electron beam passing hole portion having a predetermined diameter. This is a method for manufacturing a shadow mask characterized by the following.

[Embodiments of the invention]

Next, an embodiment of the shadow mask manufacturing method of the present invention will be described with reference to FIGS. 6' to 10.

First, a photoresist film t2a f7!3) is formed on both main surfaces of a shadow mask material Qυ made of a long mild steel plate or an amber plate, and then this photoresist film (2a+, :□□
□ A negative master plate having a negative pattern for small holes and a negative master plate having a negative pattern for large holes are brought into close contact with each other and subjected to an exposure process and a development process to form a photoresist film (diameter (d, ) and a photoresist film (24G!) with a small hole forming part (24) of diameter (d4) and a large hole forming part (25) of diameter (d4) on the photoresist film (23).
31 is removed, and the small hole forming part ρX and the large hole forming part MB (25
The photoresist film (27J) was photocured except for 1 (23 remained).

Next, as shown in FIG. 7, the etching solution is sprayed from the two sides of the shadow mask material (2υ) to etch the structure 1 so that the opening diameter of the small hole (6) becomes (D3). Of course, in this case, a shallow large hole portion (271) is also etched from the large hole forming portion c2.

Next, as shown in FIG.
A caustic soda bath solution with a concentration of 15q6 and a temperature of 80°C was sprayed from the main surface where the small holes (4) were formed.

The photoresist film C21 is removed, washed with water, and dried.

Next, as shown in FIG. Aqueous resist such as casein T8-5 manufactured by Fuji Pharmaceutical Co., Ltd.
and ammonium dichromate in a weight percent of approximately 100:1.
and diluted with water to have a specific gravity of 1.0400,
The second was Wasshin Chemical Industry KK Lacquer 418 clear and Taka 3000 thinner prepared in a ratio of 1:2 by weight, and the third was Micro Crystalline Wax 209.
5. Good results were obtained using Watanabe Yugyo KK.

In this way, the etching solution is sprayed from a main surface different from the main surface on which the resistive layer example is formed, and the diameter (D4) is
A second etching is performed to form the large hole (27), but the amount of this etching is smaller than the small hole (2 (2) in the resistive layer 2
It is necessary to expose the electron beam 1 and form an electron beam passage hole having a predetermined diameter.

Next, the resistive layer (2→ and photoresist film CA) is removed, and the first ()
A shadow mask (actually a flat mask) in which a predetermined electron beam passing hole (29) is drilled as shown in the figure is completed.
s) is 90 μm (Di) is 180 μm, which is extremely fine.

According to the shadow mask manufacturing method of this embodiment, there is no generation of pinholes or bubbles caused by the eaves (2,) of the photoresist film (2) as in the conventional method, and a shadow mask of extremely high quality can be produced. You will be able to get it.

In the above example, as shown in FIG. 7, after forming small holes and shallow large holes on both sides of the shadow mask material, the main surface of the shadow mask material on the shallow large hole side was covered with a sheet. However, the present invention is not limited to this, and the state shown in FIG. 6, that is, before the first etching process, the main surface of the shadow mask material on the large hole side is covered with a sheet, and only the small holes are formed by etching. After that, a resistance layer may be formed,
The same effect can be achieved even if the resistance layer is provided on the large hole side rather than on the small hole side, but the diameter of the electron beam passage hole is actually determined at a position extremely close to the opening of the small hole. It is preferable to do as in the previous embodiment.

In addition, although a magnetic sheet was used as the sheet in the example, it is not limited to this; a chemical-resistant organic film may also be used, and a method of adhering it to the shadow mask material via adhesive outside of the flat mask may also be used. Of course, it is also possible.

〔Effect of the invention〕

As described above, the shadow mask manufacturing method of the present invention has good adhesion within the holes of the resistive layer, eliminates defects such as pinholes and bubbles in the electron beam passage holes, and produces a shadow mask of extremely high quality. can be obtained, so its industrial value is extremely large.

[Brief explanation of drawings]

1 to 5 are explanatory cross-sectional views showing an example of a conventional method for manufacturing a shadow mask in the order of steps, and FIGS. 6 to 10 are sectional views showing an example of the method for manufacturing a shadow mask of the present invention in order of steps. It is a sectional view for explanation. 1.21...Shadow mask material 2, 3, 22, 23...Photoresist film 4.24--Small hole forming part 5,25 Large hole forming part 6...Small hole part
7, 27...Large hole 7+, 27+...Shallow large hole 8.28...Resistance layer 9.29...Electron beam passage hole 31...Magnetic sheet

Claims (1)

[Claims] A step of leaving a photosensitive film on both main surfaces of the shadow mask material except for the small hole forming portion and the large hole forming portion, respectively, and etching from either the small hole forming portion or the large hole forming portion to a desired depth. a step of covering a main surface of the shadow mask material different from the first hole with a sheet;
removing the photoresist film of the shadow mask material in which the holes are formed and forming a resistive layer of an etching resistant solution in the first holes and on the shadow mask material; removing the sheet; a second etching step of exposing the resistive layer from the coated main surface of the sheet through the small hole forming portion or the large hole forming portion and etching to form an electron beam passing hole portion of a predetermined diameter; A method for producing a shadow mask, comprising: