JPH02103841A - Manufacture of shadow mask - Google Patents

Abstract

PURPOSE:To facilitate formation of an electron beam passage hole of specified dimensions by exfoliating a resist film on the side of a small aperture pattern after preceding etching so as to form an etching resistant layer at the exfoliated face. CONSTITUTION:Photosensitive films 20 are formed on both sides of a mask material 12, and patterns of original plates 21a and 21b are baked and developed so as to form resist films 22a and 22b, and both sides of the mask material 12 are etched at the same time, with a small aperture side down, so as to form a recess 23a of specified dimensions. Next, a protective film 24 is attached to the aperture pattern side, and after exfoliating the resist film 22a on the side of the small aperture pattern, an etching resistant layer 25 is formed, and a protective film 24 is removed with the etching resistant layer 25 side up, and the large aperture pattern side is etched so as to form a recess 23c leading to the recess 23a of the specified dimensions. Hereby, it can remove generation of bubbles arising in the recess 23a at the latter etching, and also the pollution at the opposite side face is prevented, and the scattering of hole dimensions can be lightened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a method of manufacturing a shadow mask for a color picture tube.

(Prior Art) In general, a shadow mask type color picture tube, as shown in Fig. 5, consists of a spherical panel (1) and a funnel-shaped funnel (2) integrally joined to this panel (1). A shadow mask (4) is arranged inside the panel (1) at a predetermined distance from and facing a phosphor screen (3) made of a three-color phosphor layer formed on the inner surface of the panel (1). It is set up.

This shadow mask (4) is emitted from an electron gun (6) disposed within the neck (5) of the funnel (2).
The purpose is to select the electron beams (7B), (7G), and (7R) and make them hit the three-color phosphor layer correctly. A mask body (8) in which an electron beam passage hole is formed, and a mask frame (9) that supports the peripheral part of this mask body (8).
), and as shown in Figure 6, the mask body (
The electron beam passage hole 8) prevents the electron beam colliding with the shadow mask (4) from deflecting in the direction of the fluorescent screen (3).
The phosphor screen opening Dp is formed to have a larger shape than the electron gun side opening De (Dp>De).

By the way, recently, as a component of video and audio equipment, full square (F
A color picture tube in the form of 5 squares has been put into practical use. On the other hand, regarding the roughness of the screen, in order to support teletext broadcasting, medium- to high-definition screens such as various display tubes and character tubes have been put into practical use.
With the expansion of their uses, products ranging from small to ultra-large have appeared.

In such medium- and high-definition color picture tubes, it is necessary to particularly refine the shadow mask, and the electron beam passage holes in the mask body and their arrangement pitch are smaller than the shadow masks of ordinary color picture tubes. A shadow mask is used.

In addition, as a shadow mask built into a color picture tube with a flat panel or an ultra-large color picture tube, it prevents the doming phenomenon caused by thermal expansion caused by electron beam collisions and howling caused by external vibrations of speakers, etc. In order to achieve this, carbon steel (instead of Δ), it is made of a low thermal expansion material such as invar, or the thickness of the mask material is increased.

Generally, such a shadow mask uses a band-shaped mask material and uses photolithography to form a photoresist film → expose →
It is manufactured through the steps of development, burning, and etching, and is especially suitable for medium-sized and small-sized etchings with small electron beam passage holes and their arrangement pitch.
High-definition shadow masks and thick shadow masks are difficult to manufacture using conventional shadow mask manufacturing methods, and are manufactured using a so-called two-stage etching method.

As an example, Japanese Patent Publication No. 57-26345 discloses the following manufacturing method.

In this manufacturing method, as shown in FIG. 7(A), resist films (13a) and (13b) having opening patterns of different sizes are formed on both sides of a mask material (12), and then (B) ), the small hole pattern side of this mask material (12) faces upward and is etched from both sides. Recessed hole (14
a), (14b) is formed. Then, after washing with water and drying, as shown in (C), an etching-resistant material such as 7Sulfal 1~, paraffin, or synthetic resin is applied to the side of the small hole pattern (the surface where the holes (14a) are formed). An etching resistance layer (15) is formed by spray coating. Next, etching is performed only from the large hole pattern side (post-etching), and as shown in (D), the hole (1/Ib) on the large hole pattern side is enlarged to form a hole (14a). A communicating concave hole (14C) is formed. Thereafter, the resistive layer (15) and resist film (13a) are washed with water, and the resistive layer (15) and resist film (13a)
13b) is peeled off.

According to this manufacturing method, the mask cable 1Δ(12) has a plate thickness of 4
A shadow mask with a hole size of about 0% can be formed. However, when a shadow mask is manufactured using this method, the resist film (13a) is
, Corrosion resistance of (13b), ie resist film (13a)
, the adhesion of (13b) is reduced and the opening pattern is distorted, and the resist film (13b) is
Side etching progresses due to a decrease in the adhesion of the -C hole cutting method, and the variation in the -C hole cutting method increases. Furthermore, the hole shape is disturbed due to the distortion of the recessed hole pattern, thereby reducing the quality of the shadow mask. Further, in this manufacturing method, the etching resistance layer (15) after the pre-etching is as shown in FIG.
Due to the overhanging portion (16) of the film (13a) on the resist 1 overhanging the recess (14a) due to side etching, the etching-resistant material does not flow into the recess (14a).
This causes bubbles to remain in the concave holes (14a), and the etching of the remaining portions of the bubbles progresses faster than other portions, resulting in a change in flower shape. Furthermore, since the small concave hole pattern side is facing upward during the pre-etching process, uneven etching liquid pools are created on the mask material (12), and this liquid pool interferes with uniform etching, so the hole size is determined. The size variation of the concave hole (14a) is important.
Which problem is in 'c'?

(Invention or problem to be solved) As mentioned above, compared to a normal shadow mask, electron beam) Il! As a method for manufacturing medium- to high-definition shadow masks with small through holes and their arrangement pitches, and shadow masks with thick plates, there is a method of performing d3 etching in two stages, front and rear. However, in the conventional two-stage J2J method, an overhanging part of the resist film is formed on the recessed hole due to site etching during the previous etching process, and when forming the etching resistance layer, the overhanging part forms inside the recessed hole. Air bubbles are formed in the flower, which changes the flower shape during the subsequent etching process. Also,
During the first stage of etching, the small hole pattern side is facing upward, which causes an uneven etching solution pool on the mask material, which causes the problem of variations in the hole size on the small hole pattern side, which is important in determining the hole size. be.

This invention was made to solve the above-mentioned problems, and is suitable for medium- to high-definition shadow masks with small electron beam passing hole sizes and small arrangement pitches, and thick shadow masks. It is an object of the present invention to provide a method for manufacturing a shadow mask that can easily form an electron beam passage hole.

[Structure of the invention] (Means for solving the problem) In a method for manufacturing a shadow mask by photolithography,
After forming a resist film with aperture patterns of different sizes on both sides of the mask material, first, with the small aperture pattern side facing downward, both sides are etched at the same time (previous etching), and then the small aperture pattern side is etched. A concave hole of a predetermined size is formed, then the resist film on the side of the small concave pattern is peeled off while protecting the large aperture pattern side, and further an etching resistance layer is formed on the peeled surface of this resist film. After that, turn the etching resistance layer formation side to one side, release the protection on the large hole pattern side, and then etch the large hole pattern side (in order to perform the subsequent etching). A recessed hole communicating with the recessed hole on the aperture pattern side is formed.

In addition, especially in this method of manufacturing a mask,
The first etching process and the second etching process are separated and performed independently.

(Function) As mentioned above, after the previous etching, when the resist film on the side of the small opening pattern is peeled off and an etching resistance layer is formed on the peeled surface, the resist film overhangs the recessed hole. It is possible to eliminate air bubbles generated within the flower, and it is possible to eliminate changes in the shape of the flower that occur due to the air bubbles.

In addition, if etching is performed with the small hole pattern side facing downward during the previous stage etching, there will be no uneven etching liquid pool on the small hole pattern side, which will reduce the hole size on the small hole pattern side, which is important for determining the hole size. Variations can be reduced.

In particular, if the earlier etching step and the later etching step are separated and made independent, the earlier and later etching steps can be performed under independent and optimum etching conditions.

(Example) Hereinafter, the present invention will be described based on an example with reference to the drawings.

As shown in FIG. 1(A), the plate thickness is 0.13mm made of aluminum quilted low carbon steel. A photosensitive agent containing alkali caseinate and ammonium dichromate as main components is applied to both sides of the strip-shaped mask material (12) and dried to a thickness of approximately 5 μm.
A photoresist film (20) of m is formed.

Next, as shown in (B), on both sides of the mask material (12) on which the photoresist film (20) is formed, a diameter of
, oao#, 0.150. A pair of negative master plates (21a) and (21b) on which dot patterns of are formed at the same pitch.
) in close contact with each other, e.g.
The photoresist film (20
) on each negative master plate (21aL (21b)).

Next, as shown in (C), this photoresist film (20) is developed to remove the unexposed portion, and the pair of negative original plates (21a) and (21b) are applied to both sides of the mask element IJ (12). 1 to form resist films (22a) and (22b) having concave patterns of different sizes corresponding to the patterns.

Further, in order to enhance the corrosion resistance of the resist films (22a) and (22b), they are dried for about 2 minutes in an atmosphere of 150°C and then baked for about 2 minutes in an atmosphere of 200°C.

After that, this mask element IJ (12) is horizontally and (D
) As shown in Figure 2, spray the tucking liquid on both sides with the small hole pattern side facing downward, and then drill the holes (23a) on both sides until the holes (23a) on the small hole pattern side reach the specified depth.
23a) and (23b) are formed (first stage etching). After that, it is washed with water and dried, and then as shown in ([),
A protective film (24) made of polyethylene, polypropylene or vinyl chloride is pasted on the large concave pattern side (concave hole (23b) side), and a caustic soda solution of 15% concentration and 60'C is sprayed on the small concave pattern side. Then, the resist film (22a) on the side of the small opening pattern is peeled off. As shown in Figure 1, the mask material (12) is turned over so that the small hole pattern side faces upward, and a roller coater is used to apply milk caseinate alkali, polyvinyl alcohol, and epoxy to the peeled surface of the upward resist film. A water-soluble etching-resistant material such as a dispersion resin or an alkyd resin is applied and dried to form an etching-resistant layer (25).

The etching resistance layer may be not only water-soluble but also water-insoluble, such as paraffin, petroleum pitch, and lacquer. However, in the case of water-insoluble
After removing the resist film, it is necessary to thoroughly wash it with water and dry it before applying it.

In addition, regardless of whether it is water-soluble or non-water-soluble, the application method is as follows:
In addition to the roller coater method, spray methods, dipping methods, bar coater methods, etc. can also be used.

Next, as shown in (G), remove the protective film (24) on the side of the large concave hole pattern, spray the etching solution with the large concave pattern side facing downward, and open the concave hole (23b). A recessed hole (23a) communicating with a recessed hole (23a) of a predetermined size formed in the part by the above-mentioned previous stage elatching.
23C) (later etching). That 1l (
As shown in IJ), the resist film (22b) and the etching resistance layer (25) are peeled off, and the required flange 1 to mask (26) are removed.

FIG. 2 shows a manufacturing line for the etching process of the method for manufacturing the V-tow mask.

In this production line, a plurality of chambers are arranged in series along a mask material (12) that is moved with its plate surface horizontal. In other words, the mask element +J(12) indicated by the arrow
Sequentially in the traveling direction of the mask material (12), there is an etching chamber (a) at the front stage in which a number of nozzles (28) are arranged to spray etching liquid on both sides of the mask material (12), a water washing spray nozzle (29) c15, and a drying device (not shown). -), a resist film peeling chamber (b) with a protective film (24) pasted on the upward facing side and a spray nozzle (30) for peeling off the resist film on the downward facing small concave pattern side A washing and drying chamber (d) equipped with a chamber (C), a washing spray nozzle (31), and a drying device if necessary, an etching resistor on the top surface with the peeled surface of the resist film of the inverted mask material (12) as the top surface. The roller coater (32) that applies the material is removed from the etching resistor (32), the protective film (24) is removed, and the drying device (33) is equipped to avoid drying the etching resistor coated in the previous step. A rear etching chamber (g) is installed in which a number of nozzles (28) are arranged to spray an etching solution onto the lower surface of the chamber (f) and the mask line 1/j (12), and the etching chamber (g) is installed in the chamber (f) and the rear stage etching chamber (g) is provided with a number of nozzles (28) for spraying etching liquid onto the lower surface of the mask line 1/j (12). It has a continuous structure.

By the way, as in the manufacturing method of this example, after the first stage etching, the resist film (22a) on the side of the small opening pattern in which the recessed hole (23a) of a predetermined size is formed is peeled off to form the etching resistor IW (25). Then, it is possible to prevent the generation of bubbles that have conventionally occurred in the concave hole due to the overhang of the resist film over the concave hole, and it is possible to eliminate the change in the flower shape that occurs in the remaining portion of the bubble. Furthermore, when forming the etching resistance layer (25), the opposite side is covered with a protective film (24) and C is formed.
It is possible to reliably prevent contamination of the opposite side where multi-stage etching is performed, and reduce variations in the final hole machining method.

Roughly speaking, during the previous stage etching, the small concave pattern side is facing downward] - Because etching is performed, uneven etching is performed on the mask element vJ' (12) J = as in the conventional etching)
This has the effect of reducing variations in the size of the concave holes (23a) on the side of the small concave hole pattern, which is important in determining the predetermined hole size.

Next, FIGS. 3 and 4 show another manufacturing line different from the etching "A manufacturing line" shown in the above embodiment. In this manufacturing line, the front stage etching and the rear stage etching are separated. This is a production line that runs independently 41i', and as shown in Figure 3, the mask +-Jf (12) is
After passing through the lower joining chambers (a) to (f) similar to the eratin line shown in the above embodiment and completing the etching of the first stage, it is wound up on the "1-ra" (34).The etching of the second stage is , as shown in FIG. 4, the wound mask element 4 and J(12) are unwound 41 and rolled up 4r. In this FIG. The subsequent etching chamber (h) similar to the eratin line is a water washing chamber with water washing nozzles (29) arranged above and below, and (i) is a stripping chamber where a spray nozzle (30) for stripping the resist film and etching resistance layer is arranged. , (j) is a water washing chamber similar to the water washing chamber (h) in which washing nozzles (29) are arranged above and below, and (k) is a drying chamber equipped with a drying device (33).

In this way, when the production line is separated into the front-stage etching line and the rear-stage etching line, after the front-stage etching, the dimensions of the recessed holes on the small recessed hole pattern side are measured and confirmed.
By controlling the subsequent etching based on the size of the recessed hole, it is possible to easily obtain the exact hole size ultimately required.

That is, when etching a shadow mask, when the mask material is low carbon steel, the temperature, specific gravity, spray flow rate, and Fe++4 of the ferric chloride solution, which is the etching solution, are
ion, Fe1 ion, free hydrochloric acid, and maskmeal HA
In the case of a low thermal expansion material made of a N1-re alloy, it is also necessary to control Ni (+ ions), and after accurately controlling these, the traveling speed of the mask material is appropriately controlled to achieve a predetermined hole size. Therefore, if the first stage etching and the second stage etching are performed continuously on the same line, even if the usage of the holes on the small hole pattern side is precisely controlled in the first stage etching, the mask at that time The subsequent etching must be performed at the traveling speed of the material, and the subsequent etching cannot be controlled by the traveling speed of the mask material.In other words, etching is performed at the traveling speed most effective for hole size control. It is difficult to control the C flaws and achieve the desired hole size.However, if the front etching and the rear etching are separated and performed on independent lines as in this example, the front etching is difficult. The subsequent etching can be carried out at any running speed regardless of the etching process, and it is possible to easily and accurately form the hole to the desired size. This method can be said to be suitable for manufacturing shadow masks, which are becoming increasingly diverse in terms of materials, thickness, and thickness.

For example, to explain the etching of a thick shadow mask, no matter how thick the mask material is, the size of the holes on the side of the small hole pattern formed in the previous stage of etching is constant regardless of the thickness. In this case, it is naturally desirable to slow down the running speed of the mask material in the later stage etching, but if the former stage etching and the latter stage etching are performed continuously on the same line, it is recommended to slow down the running speed of the mask material. Since the amount of etching increases, a troublesome adjustment work is required, for example, changing the liquid temperature spray flow rate in the previous stage of etching according to the thickness of the mask material. However, if the front-stage etching and the rear-stage etching are separated and carried out on independent lines as in this example, the front-stage etching can be performed under the optimal conditions of keeping the predetermined concave hole size 1. Therefore, a concave hole of a predetermined size can be stably formed on the small aperture button side. Furthermore, regardless of the etching in the previous stage, in the etching in the latter stage, it is necessary to adjust the temperature, ratio, spray flow rate, etc. of the etching solution to perform etching at the required running speed. This means that, for example, even if the etching resistance layer is only peeled off sufficiently after the subsequent etching, the temperature of the etching solution in the subsequent etching can be lowered and the traveling speed of the mask material slowed down to perform etching for a sufficient amount of time. It also facilitates controls other than etching, such as peeling off the etching resistance layer.

[Effects of the invention] Regime with hole patterns of different sizes and serrations on both sides
~ Etch both sides of the mask material with the film formed on it with the small hole pattern side facing downward, then protect the side where the large hole pattern is formed and peel off the resist film on the side where the small hole pattern is formed. Furthermore, an etching resistance layer is formed on the peeled surface of this resist film, and then, when the side on which the etching resistance layer is formed faces upward and the large opening pattern side is exposed to etching liquid, the etching process is performed in the previous step. It is possible to eliminate air bubbles caused by the overhang of the resist film, and it is possible to eliminate changes in the flower shape caused by the air bubbles.

Further, when forming the etching resistance layer, since the opposite surface is protected, contamination of the opposite surface on which subsequent etching is performed can be prevented, and variations in hole size can be reduced. Furthermore, if etching is performed with the side where the small hole pattern is formed facing downward during the previous etching step, uneven etching liquid pools on the side of the small hole pattern will be eliminated, and the recesses on the side of the small hole button, which are important for determining the hole size, will be removed. Variations in hole size can be reduced. Therefore, by using them, a shadow mask having an electron beam passage hole of a predetermined size can be easily manufactured.

In particular, in this shadow mask manufacturing method, if the front-stage etching and the rear-stage etching are separated and performed independently, regardless of the quality or thickness of the mask material,
In the first stage of etching, a concave hole of a predetermined size is stably formed on the small hole pattern side, and then the second stage of etching can be easily performed by controlling the etching conditions regardless of the first stage of etching. You can also make a Shadow 1 bear mask.

[Brief explanation of drawings]

1 to 4 are detailed explanatory diagrams of the present invention, and FIG. 1 is a configuration diagram of a manufacturing line that performs first-stage etching and second-stage etching in succession; FIGS. 3 and 4 are configuration diagrams of a manufacturing line that separates first-stage etching and second-stage etching; 4 is a block diagram of a rear etching line, FIG. 5 is a block diagram of a color picture tube, and FIG. 6 is a cross-sectional view without showing the shape of the electron beam passage hole of the shadow mask. FIGS. 7A to 7D are process diagrams for explaining a conventional method of manufacturing a shadow mask, respectively, and FIG. 8 is a diagram showing how the resist film extends by one inch after etching in the previous stage. 12... Mask line i, 'J 20... Photoresist film 22a, 22b... Film 23a, 23b to resist 1... Hole 24... Protective film 25... Etching resistance layer

Claims (2)

[Claims] (1) A process of forming a photoresist film on both sides of the mask material, and printing and developing the original pattern on the photoresist film on both sides to form a resist film having aperture patterns of different sizes on both sides of the mask material. a pre-etching step of simultaneously etching both sides of the mask material on which the resist film is formed with the small opening pattern side facing downward to form a concave hole of a predetermined size on the small opening pattern side; After protecting the aperture pattern side and peeling off the resist film on the small aperture pattern side, forming an etching resistance layer on the peeled surface of the resist film, with the etching resistance layer formation side facing upward and A subsequent etching step includes removing the protection on the large hole pattern side, etching the large hole pattern side, and forming a concave hole on the large hole pattern side that communicates with the concave hole on the small hole pattern side. A method for producing a shadow mask, comprising: (2) The method for manufacturing a shadow mask according to claim 1, wherein the first etching step and the second etching step are performed separately and independently.