JP2002270092A - Method of manufacturing shadow mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a shadow mask capable of providing a high quality shadow mask by suppressing faults in the shadow mask such as unevenness of electron beam through holes, residual resist, bending and wrinkles due to an insufficient degreasing treatment of a metal thin plate or a removing treatment of a resist thin film in a process after the degreasing treatment by using a predetermined solution which are needed to form the shadow mask. SOLUTION: The metal thin plate 11 is degreased or a resist coat formed on a metal thin plate 11 face is removed by supplying the required treating solution to a nozzle device 12 in 1-10 Pa, supplying gas in 1-5 Pa, mixing the solution and gas inside the nozzle device 12, and spraying the mixture from a spray hole 25 of the nozzle device 12 onto the metal thin plate 11 face forming the shadow mask.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a shadow mask for a color cathode ray tube using a photoetching method.

[0002]

2. Description of the Related Art In general, a color cathode ray tube used for a color television receiver, a color terminal display and the like has a face panel 51 having a substantially rectangular screen as shown in FIG. Has an envelope having a funnel 52 integrally joined to the housing. On the inner surface of the face panel 51, a black matrix type or black stripe type phosphor screen 53 having three color phosphor layers emitting blue, green and red light is formed. Further, in the envelope, a shadow mask 55 for performing color selection through which an electron beam 54 composed of a center beam 54G and a pair of side beams 54B and 54R passes is disposed facing the phosphor screen 53. Have been. The shadow mask 55 is fixed to a mask frame 56 and the mask frame 56
Are attached to the inner surface of the face panel 51 via stud pins (not shown), and a magnetic shield 57 is also attached to the mask frame 56. Further, electron beams 54B and 54B are provided in a neck 58 of the funnel 52.
For example, an in-line type electron gun 5 emitting G, 54R
9 are provided. The electron beams 54B, 54G and 54R emitted from the electron gun 59 are deflected by a magnetic field generated by a deflection yoke 60 mounted outside the funnel 52, and the phosphor screen 53 is irradiated with the electron beams 54B, 54G and 54R. By scanning in the horizontal and vertical directions, a color image is reproduced and displayed on the phosphor screen 53.

The deflection yoke 60 has three electron beams 54B and 54G as non-uniform magnetic fields in which a horizontal deflection magnetic field generated by a horizontal deflection coil is a pincushion type and a vertical deflection magnetic field generated by a vertical deflection coil is a barrel type. , 54R are self-convergent.

As shown in FIG. 5, the shadow mask 55 has a structure in which a large number of electron beam passage holes 62 are formed in a substantially rectangular thin metal plate 61. The opening shape of the electron beam passage hole 62 is roughly classified into two types, a circular dot type and a rectangular slit type. The electron gun 59 side has a small hole 63, and the phosphor screen 53 side has a large hole. A communication hole 65 is provided. Color cathode ray tubes for displays that mainly display characters and graphics
Mainly circular dot type electron beam passage hole 62
The shadow mask 55 having a rectangular slit-type electron beam passage hole 62 is mainly used for a consumer color cathode ray tube such as a color television receiver.

The shadow mask 55 is generally manufactured by a photo etching method. That is, as shown in FIG.
1 is supplied to a degreasing means, and the surface of the thin metal plate 61 is degreased and washed, then washed with water, and a photosensitive agent is applied to both surfaces to form a photoresist film having a thickness of about 7 to 8 μm.

Next, a pair of photomasks, in which patterns corresponding to the large holes 64 and the small holes 63 forming the shadow mask 55 are formed on the photoresist films on both surfaces, are mounted using a vacuum contact printing apparatus. Exposure to print a photomask pattern on both sides of the photoresist coating.

Next, the photoresist film on which the pattern has been baked is developed with hot water to remove the unexposed portions, thereby forming a resist pattern in which the mask material surface where the communication holes 65 are to be formed is exposed.

Next, this resist pattern is heated to about 200 ° C.
To increase the corrosion resistance of the etching performed thereafter. Next, an etching solution composed of a ferric chloride solution heated to 60 ° C. or higher is sprayed on both surfaces of the material surface of the metal sheet 61 on which the resist pattern is formed, and a large hole 64 is formed from one surface of the metal sheet 61. , A small hole 6 from the other side
3 is etched to form a communication hole 65 in which the large hole 64 and the small hole 63 communicate.

Thereafter, the resist film remaining on both surfaces of the thin metal plate 61 is peeled and removed, and is pressed into a predetermined shape to manufacture a shadow mask.

As shown in FIG. 5, in any of these shadow masks 55, basically, the cross-sectional shape of the opening forming the electron beam passage hole 62 is opposed to the phosphor screen 53 of the thin metal plate 61. Large hole 64 formed on the surface side
And a small hole 6 formed on the side opposite to the electron gun 59.
The electron beam passage hole 62 is formed as a communication hole 65 in which the large hole 64 and the small hole 63 communicate with each other.
The electron beam passage hole 62 has a large hole 64 and a small hole 63.
A matching point 66 where the bottoms of the two are connected substantially determines the opening diameter of the electron beam passage hole 62.

A phosphor screen 53 of a color cathode ray tube
Is formed by a photolithography method using the shadow mask 55 as a photomask. Therefore, the size and shape of the matrix holes of the black matrix and the dot-shaped three-color phosphor layer constituting the phosphor screen 53 are different from those of the shadow mask 55. It greatly depends on the size and shape of the opening. Variations in the opening size and shape of the shadow mask 55 appear as spots on the displayed image as they are, and impair the image quality. Therefore, the opening of the shadow mask 55 is required in accordance with a strong demand for higher definition and higher quality. Attempts have been made to reduce the size and reduce the variation in the opening size. Such a demand is particularly strong in a color cathode ray tube for a color display.

The thin metal plate 61 serving as the base material of the shadow mask 55 is used for improving the adhesion of the resist film, or in the annealing step before the shadow mask 55 is press-formed and processed into a predetermined shape. In order to prevent this, it is general to provide an appropriate roughness on the surface of the thin metal plate 61. On the other hand, the provision of the roughness on the metal thin plate 61 is a factor that makes it difficult to remove the rust-preventive oil, dirt, and the like due to the roughness when removing the rust-preventive oil and dirt.

The degreasing solution used in the degreasing step is supplied onto the thin metal plate 61 by dipping or spraying. If the degreasing and dirt removal are insufficient, the adhesion of the resist film may be uneven. Become. For this reason, a slight difference is caused in the progress speed of etching, so that uniform etching cannot be performed, and etching is inhibited by adhesion of dirt. As a result, the diameter of the electron beam passage hole 62 becomes smaller than a predetermined value. There is a problem that the electron beam passing hole 62 having a predetermined diameter cannot be formed because the size becomes large or small.

In a consumer color cathode ray tube such as a color television receiver, the size of a screen is increased, and a flat square having a flat screen with little reflection of external light and little image distortion is provided. Tubes are the current mainstream. Moreover, recently, a completely flat tube in which the outer surface of a face panel 51 for displaying an image has a substantially completely flat shape similar to a sheet glass has been well received in the market, and will be a mainstream color cathode ray tube in the future. it is conceivable that.

Generally, the effective surface of the shadow mask 55 facing the phosphor screen 53 is formed in a shape corresponding to the inner surface shape of the face panel 51, and the shadow mask 55 of the flat square tube is the shadow mask of the conventional color cathode ray tube. Although the curvature of the mask is smaller than that of the mask 55 (the radius of curvature is large), in a completely flat tube, flattening is achieved by further reducing the curvature.

These shadow masks 55 have a thickness of 0.1 mm.
It is manufactured from a very thin metal sheet 61 of about 1 mm to 0.3 mm. In order to form a shadow mask 55 corresponding to a large screen with such a thin metal plate 61, it is necessary to consider the arrangement state of the electron beam passage holes 62, the inner surface shape of the face panel 51, and the like as much as possible.
Various measures have been devised so that the curved surface of the shadow mask 55 can be maintained for a long period of time by, for example, designing the curved surface to be close to a spherical surface.

Even with this configuration, the shadow mask 5
The deterioration of the molding tension strength and the howling characteristics of 5 occur, but one of the simplest methods for preventing such deterioration of the strength of the shadow mask 55 is to reduce the thickness of the metal sheet 61 constituting the shadow mask 55. This method is to increase the thickness. However, when the thickness is increased, the resist film is required to have further etching resistance and adhesion. The resist film with enhanced etching resistance and adhesion tends to have a deteriorated peeling property. Simply applying a stripping solution to the thin metal plate 61 with the resist film by immersion or spraying even after the stripping process is performed. A part of the resist film remained, and complete etching could not be performed, so that the electron beam passage hole 62 of the shadow mask 55 was clogged.

[0018]

In the conventional method for manufacturing a shadow mask, when performing a degreasing treatment and a peeling treatment, the treatment liquid is applied by dipping or spraying. However, such a treatment by immersion has a slower reaction speed than the spray treatment, requires a longer treatment time, and is inferior in the ability to remove fine irregularities and resist patterns. In addition, in the method by spraying, the ability to remove dirt on minute irregularities on the surface of the metal sheet and the resist film with improved etching resistance is superior to the processing method by immersion, but the processing is particularly performed on the upper surface side of the metal sheet to be processed. The liquid accumulates on the upper surface of the metal sheet, making it impossible to effectively use the spraying force and fineness of the spray particles, and the diameter of the electron beam passage hole fluctuates to a predetermined value, There has been a problem that the hole diameters become irregular or the holes are clogged.

Japanese Patent Application Laid-Open No. Hei 8-294679 discloses a method of spraying a mixture of a solution and a gas by improving the method of spraying such a single processing solution. . According to the precision cleaning device described in this publication, a liquid (solution) and a gas are separately introduced, and the liquid and the gas are mixed by an extension nozzle provided on an extension of the main body, and the opening at the tip of the nozzle is opened. The object to be cleaned is washed by ejecting the gas-liquid mixture from the surface. At this time, by setting the length of the extension nozzle to 1.5 to 20 times the inner diameter of the nozzle, the pressure and the speed are set to be good so that the cleaning can be surely performed.

In such a cleaning apparatus, it is considered that cleaning of an object to be cleaned such as a liquid crystal substrate or a semiconductor wafer can be performed satisfactorily. However, a shadow mask made of a thin metal plate, particularly having a roughness. It is insufficient for application to degreasing of a metal thin plate or removal of a resist film, and there is a strong possibility that reliable degreasing or removal of the resist film will not be performed.

Japanese Patent Application Laid-Open No. 2000-450 discloses a fluid jet nozzle applied to metal etching.
No. 81 discloses this. According to the metal etching method described in this publication, a solution and a gas for etching a metal surface are mixed and ejected from a nozzle, and the fine droplets collide with the metal to etch the metal. Further, it is said that the supply amount of the finely divided etching solution per unit area of the metal surface can be reduced, and the generation of the solution pool can be suppressed.

In such an etching method, 2
It is presumed that etching can be performed well by ejecting microdroplets at a speed higher than the sound speed using a fluid jet nozzle, but this method is simply applied to degreasing shadow masks or removing resist coatings. In such a case, it is necessary to consider the relationship between the large holes and small holes that form the electron beam passage hole, or bends and wrinkles, etc. Is not disclosed at all, and the disclosed etching method cannot be simply applied to a degreasing treatment or an etching film removal treatment as it is.

SUMMARY OF THE INVENTION The present invention has been made in view of these problems, and has a method of manufacturing a shadow mask capable of manufacturing a high-quality shadow mask by suppressing irregularities in hole diameters and clogging of the holes. The purpose is to provide.

[0024]

According to the present invention, there is provided a degreasing step for degreasing a supplied metal sheet using a degreasing solution, and forming a resist by applying a photosensitive agent to the degreased metal sheet. A step of exposing and developing the resist surface to form a predetermined resist pattern, a step of etching the metal sheet on which the resist pattern is formed, and a step of removing the etched metal sheet with a solution for removing a resist. In a method of manufacturing a shadow mask comprising a removing step of removing a resist by using a method, at least one of a degreasing step and a removing step
A processing liquid of 〜１０10 Pa and a gas of 1 ５5 Pa are supplied from separate supply ports, and the two are mixed in a mixing chamber of the nozzle device. The mixed processing liquid is passed through an orifice and then ejected from a nozzle. Is sprayed onto a thin metal plate.

By doing so, the degreasing treatment and the peeling-off treatment can be performed effectively and surely. As a result, irregularities in the hole diameter and clogging of the shadow mask can be suppressed, and a high-quality shadow mask can be obtained. Can be done.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a shadow mask and a processing apparatus therefor according to the present invention will be described in detail with reference to the drawings. Note that the overall configuration of the color cathode ray tube and the shadow mask adopts the same configuration as the conventional configuration, and thus detailed description thereof is omitted here.

FIG. 1 is a process chart showing a method of manufacturing a shadow mask according to the present invention. First, for example, when the plate thickness is about 0.
A strip-shaped metal sheet made of 15 mm invar material or the like is supplied to a degreasing apparatus, and a treatment liquid obtained by mixing both sides of the metal sheet with a degreasing solution and a gas such as air is sprayed on the metal sheet. Both sides of the metal sheet are washed (Step A), and then washed with water to wash off the treatment liquid (Step B). Thereafter, a photosensitizer containing casein as a main component and sensitized with ammonium bichromate is applied to both surfaces of the metal sheet, and the applied photosensitizer is dried at about 100 ° C. to have a thickness of about 5 μm. (Step C).

Next, a negative master for forming a pair of photomasks in which a dot-shaped pattern corresponding to a large hole and a dot-shaped pattern corresponding to a small hole are formed on the resist film is adhered. Exposure for about 30 seconds with a 5 kW mercury lamp placed about 1 m away from
The pattern of the negative master is printed on the resist films on both sides (step D).

After that, the resist film is applied to about 40 ° C.
The resist film having a pattern corresponding to the dot pattern of the pair of negative masters is formed by spraying hot water and developing to remove unexposed portions (step E).
Further, the resist film is dried at about 150 ° C., and then baked at about 200 ° C. (Step F).

Thereafter, a protective film made of polyethylene, polypropylene, vinyl chloride, or the like is adhered to the resist coating side on which the large-diameter pattern corresponding to the negative of the large-hole dot-shaped pattern is formed, and one side is adhered. Shield (step G).

Thereafter, the resist coating side on which the dot-shaped pattern of the small holes on the opposite side is formed faces downward, and the resist coating side on which the dot-shaped pattern of the small holes is formed is placed on the opposite side.
An etching solution is sprayed as the first stage etching to form small holes having a small diameter corresponding to the dot pattern of the small holes (Step H).

Next, a treatment liquid obtained by mixing a solution composed of sodium hydroxide and a gas such as air is sprayed on the resist coating on the side of the pores, and the resist coating is peeled off and washed with water (Step I).

Thereafter, an etching resistant layer serving as a back coat layer formed by adding substantially equal amounts of, for example, milk casein, an acrylic resin and water is formed on the small hole forming surface (step J).

Thereafter, the protective film on the side of the resist film on which the large-hole dot pattern was formed was peeled off, and the resist film side on which the large-hole dot pattern was formed was turned downward. Spray. Then, large holes communicating with the small holes are formed from the dot pattern side of the large holes (step K).

Thereafter, a treatment liquid obtained by mixing a solution composed of sodium hydroxide and a gas such as air is sprayed,
The resist film and the etching-resistant layer on the dot pattern side of the large hole are removed (step L). After that, by washing and drying, a flat mask in which electron beam passage holes of a predetermined shape and size formed of communication holes in which the large holes and the small holes communicate with each other is obtained. Next, a shadow mask having a predetermined curved surface shape is completed by press molding.

A degreasing apparatus or a resist film removing apparatus used in such a shadow mask manufacturing method is configured as shown in FIG.

That is, assuming that the metal sheet 11 is supplied and conveyed in the direction of the arrow in FIG. Nozzle device 12 is disposed.
The nozzle device 12 includes a gas connection pipe 14 connected to a gas supply device 13 that supplies a gas such as air,
A solution connection pipe 16 connected to a solution supply device 15 for supplying a solution such as a degreasing solution or a stripping solution is connected.

The gas supply device 13 and the solution supply device 15 supply the gas and the solution to the nozzle device 12 by pressurizing the gas and the solution to a predetermined pressure by a pump or the like. The mixed gas and the solution are mixed at a predetermined pressure by the nozzle device 12, and the mixed processing liquid is sprayed from both sides of the conveyed metal sheet 11 as shown by a broken line in FIG. Degreasing or removal processing of the resist film (including the back coat layer) is performed.

Of course, when processing is performed only on one side of the thin metal plate 11, the nozzle device 12 may be disposed on only one side,
A valve may be provided in the middle of the connecting pipes 14 and 16 or in the nozzle device 12, and the opening / closing operation of the valve may be configured to determine whether or not the spraying operation can be performed. It is also possible to spray the mixed treatment liquid of the solution and the solution, and spray the other surface alone with the solution. If the configuration is such that the valve is operated in this manner, it is possible to use the valve appropriately and selectively according to each use, and the versatility is improved.

Such a nozzle device 12 is configured as shown in FIG. The nozzle 12 includes a solution supply port 21, a gas supply port 22, a gas / liquid mixing chamber 23, and an orifice 24.
And the injection port 25.

An embodiment of the present invention using the nozzle device 12 configured as described above will be described in more detail.

That is, a metal thin plate 14 made of an invar material having a thickness of 0.12 mm is used as a base material.
In order to perform a degreasing treatment of rolling oil, rust-preventive oil, and the like adhering to the surface, a high-temperature alkaline solution is supplied to the solution supply port 21 of the nozzle device 12 at 1 to 10 Pa,
2 to the gas / liquid mixing chamber 2 by supplying air at 1 to 5 Pa.
After the two are mixed in 3, the treatment liquid is sprayed to the surface of the metal sheet 14 from the injection port 25 through the orifice 24 to perform degreasing treatment, and a casein-based resist is applied to both sides of the water-washed metal sheet 14 and dried. A photosensitive film having a thickness of several μm is formed.

Next, the photosensitive films formed on both sides are
A photomask on which a pattern corresponding to the electron gun side of the shadow mask, that is, a small hole on the electron beam incident side, is formed;
A pair of photomasks each including a photomask in which a pattern corresponding to a large hole on the phosphor screen side of the shadow mask is formed are exposed in vacuum contact, and the patterns of these photomasks are printed.

Thereafter, the photosensitive film on which the pattern is baked is developed with water, the unexposed portion is removed and dried, followed by baking to obtain an etching resist pattern corresponding to a pair of photomask patterns. .

According to this etching resist pattern, after shielding one surface of the base material, the other surface is etched until a desired hole diameter is obtained, and then an etching-resistant back coat layer is formed. Etching of the shielded surface side is performed until the desired hole diameter is obtained by releasing the shield, and after washing with water, the resist pattern and the etching-resistant backcoat layer are formed by the same nozzle device 12 as the above-described nozzle device 12, A high-temperature alkaline solution is supplied to the solution supply port 21 of the nozzle device 12 by 1 to 1.
While supplying at 10 Pa, air is supplied to the gas supply port 22 by 1
After being supplied at ５5 Pa and being mixed in the gas / liquid mixing chamber 23, the processing liquid is sprayed from the injection port 25 through the orifice 24 onto the surface of the thin metal plate 14 to perform degreasing processing, and at the same time, remove processing is performed. After that, washing and drying are performed and necessary press molding is performed to complete a shadow mask.

As described above, the shadow mask formed by using the manufacturing method and the processing apparatus of the present invention (Embodiments 1 to 5)
Table 1 shows the results of measuring the defect rates of the shadow masks 3) and the shadow masks (Comparative Examples 1 to 8) formed by performing the processing under other conditions.

[Table 1] As can be seen from Table 1, when the pressure (supply amount) between the solution and the gas is too small, the degreasing or peeling ability becomes insufficient,
Excessive investment in equipment such as a pump is necessary, which affects the stability of metal sheet conveyance.However, in the present invention, it is necessary to manufacture a high-quality shadow mask with few defects such as large and small communication holes and remaining resist. Can be.

[0047]

As described above, according to the shadow mask manufacturing method and the processing apparatus of the present invention, the degreasing process before the resist coating and the removing process of the resist or the resist and the etching resistant layer are performed by the processing solution. And a gas are supplied to the orifice at a predetermined pressure (supply amount) ratio through separate pressure passages, and a processing liquid having a predetermined pressure obtained by mixing the two is ejected from an injection port of a nozzle device for processing. Large or small fluctuations of the electron beam passage holes in the shadow mask,
It is possible to manufacture high-quality shadow masks with extremely few defects such as remaining resist or breaks and wrinkles, and to prevent deterioration of images of color cathode ray tubes using these shadow masks. Becomes

[Brief description of the drawings]

FIG. 1 is a process explanatory view illustrating a method for manufacturing a shadow mask according to the present invention.

FIG. 2 is a schematic configuration diagram illustrating a processing apparatus used in the shadow mask manufacturing method according to the present invention.

FIG. 3 is a schematic configuration diagram showing a nozzle device constituting the processing apparatus.

FIG. 4 is a sectional view showing a conventional color cathode ray tube.

FIG. 5 is an explanatory diagram showing a shadow mask constituting the color cathode ray tube.

FIG. 6 is an explanatory process diagram for explaining the method for manufacturing the shadow mask.

[Explanation of symbols]

 11: Thin metal plate 12: Nozzle device 13: Gas supply device 15: Solution supply device 17: Body portion 18: Nozzle portion 19: Orifice 20: Gas supply port 21: Solution supply port 23: Gas / liquid mixing chamber 24: Orifice 25 ： Injection port

Continuation of the front page (72) Inventor Masaru Nikaido 1-9-2, Hara-cho, Fukaya-shi, Saitama F-term in the Toshiba Fukaya factory (reference) 5C027 HH07 HH08 HH10

Claims (1)

[Claims] 1. A degreasing step of degreased a supplied metal sheet using a degreasing solution; a step of applying a photosensitive agent to the degreased metal sheet to form a resist; and exposing the resist surface to light. Developing a predetermined resist pattern, etching the thin metal sheet on which the resist pattern is formed, and removing the etched thin metal sheet with a resist removing solution. In a method of manufacturing a shadow mask comprising the steps: in at least one of the degreasing step and the removing step, a treatment liquid of 1 to 10 Pa;
The gas of Pa is supplied from each supply port, and the two are mixed in the mixing chamber of the nozzle device. The mixed processing liquid is sprayed from the injection port of the nozzle onto the metal sheet surface through the orifice. A method of manufacturing a shadow mask.