JP3002616B2 - Metal sheet cleaning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a shadow mask and an aperture grill for a color CRT by photoetching, wherein a photoresist film is formed on the surface of a thin metal plate which is a shadow mask plate or an aperture grill plate. before, the cleaning apparatus and the sheet metal of the sheet metal to be processed cleaned and degreased and washed with water of the surface of the sheet metal
It relates to a cleaning method .

[0002]

2. Description of the Related Art A color CRT is an electron gun that emits three electron beams, a phosphor that receives the electron beams emitted from the electron gun and emits light in three primary colors, a phosphor and an electron gun. And a shadow mask or an aperture grille for selectively passing only the electron beam in a required direction of each electron beam and blocking the electron beam in an unnecessary direction. I have.

The above-described shadow mask or aperture grill is manufactured as follows. That is, a thin metal plate which is a shadow mask plate material or an aperture grill plate material such as a low carbon aluminum killed steel having a plate thickness of about 0.1 mm to 0.3 mm or an invar alloy containing 36% of nickel,
A large number of fine through holes or fine through grooves for passing an electron beam are formed by photoetching. After this etching step, the metal sheet is annealed in a non-oxidizing atmosphere in order to improve the press formability, and then the metal sheet is subjected to spherical processing by press molding, and then the heat radiation of the shadow mask or the aperture grille is performed. A black mask is applied to a thin metal plate in an oxidizing atmosphere for the purpose of improving and reducing irregular reflection of an electron beam, and an oxide film is formed on the surface of the metal thin plate, thereby completing a shadow mask or an aperture grill. Alternatively, when the above-described press forming is not performed on the metal sheet, the metal sheet is subjected to a blackening treatment without performing an annealing step after the etching step, thereby completing a shadow mask or an aperture grill.

Here, a large number of fine holes or grooves for passing an electron beam of a shadow mask or an aperture grill are formed through the following steps using a photo-etching method. That is, first, a metal thin plate which is a shadow mask plate material or an aperture grill plate material is degreased, washed with water and subjected to surface treatment, and then a photosensitive liquid is applied to both the front and back surfaces of the metal thin plate, and then dried, and the thickness is reduced. A μm photoresist film is deposited. Next, a master pattern having a required image corresponding to a fine through hole or a fine through hole for passing an electron beam to be formed is formed on the surface of each photoresist film deposited on both surfaces of the metal thin plate. Align the image positions on the back and bring them into close contact with each other, and then perform exposure. After exposure, develop using warm water, etc.,
After being immersed in a solution of chromic anhydride, the film is subjected to a hardening treatment by burning, thereby forming a corrosion-resistant film (resist film) having a required pattern image on both the front and back surfaces of the thin metal sheet. Then, after spray etching is performed using an aqueous ferric chloride solution to form a large number of fine through holes or fine through holes in the thin metal plate, the resist film is peeled off from the front and back surfaces of the thin metal plate, and the photo etching process is completed.

By the way, in the above-described series of photoetching steps, the cleaning of the metal thin plate performed prior to the application of the photosensitive liquid in order to apply the photosensitive liquid to the metal thin plate and to perform the etching well has conventionally been performed. It has been carried out using a cleaning device having a degreasing tank and a washing tank.
That is, using a cleaning device composed of a degreasing tank containing a degreasing liquid containing sodium silicate and a surfactant, and a washing tank connected to the degreasing tank, first, a shadow mask plate material or By immersing the metal sheet, which is the aperture grill plate, in the degreasing solution in the degreasing tank, coarse contaminants such as oils and fats adhering to the surface of the sheet metal are separated and removed from the surface of the sheet metal. The metal sheet carried out of the degreasing tank is carried into the washing tank and washed in the washing tank to separate it from the degreasing agent remaining on the surface of the metal sheet and the surface of the metal sheet in the degreasing tank. After that, contaminants and the like re-adhering to the surface of the metal sheet are washed off with water. Further, in order to enhance the degreasing power, electrolytic degreasing in a degreasing tank, that is, water electrolysis is performed in a degreasing solution by applying a voltage using a thin metal plate to be cleaned as an electrode, and oil components and the like are decomposed and removed by a reduction or oxidation reaction. At the same time, oil and the like are agitated and removed from the surface of the metal sheet by bubbles of hydrogen or oxygen generated at that time.

[0006]

However, in the conventional cleaning apparatus, depending on the type of the metal sheet, it may not be possible to sufficiently remove contaminants such as oil and metal powder. In order to reinforce the adhesion, there is a case where the contaminants that have entered the depth of the concave portion of the scale-like projections artificially applied to the surface of the metal sheet after the rolling process of the sheet material cannot be sufficiently removed. Also, in the degreasing tank, the contaminants once separated and removed from the surface of the metal sheet and diffused into the degreasing solution are reattached to the surface of the metal sheet, and the contaminants are not washed off in the washing tank and the metal sheet is removed as it is. It also remains on the surface.

[0007] Even after the cleaning step, if the respective steps of photosensitive liquid application, development and etching are carried out while contaminants remain remaining on the surface of the metal sheet, the metal sheet after the etching process is treated with " A defect called "white pin" occurs. In other words, if the photoresist film is formed on the surface of the thin metal sheet while the contaminant remains on the surface of the thin metal sheet, the adhesion between the surface of the thin metal sheet and the photoresist film at the site where the contaminant is adhered. Therefore, the resist at the portion is peeled off at the time of etching, and the portion that should not be corroded is corroded. Therefore, FIG. 3 is a longitudinal sectional view, and FIG. As shown in plan views as viewed from the diameter forming side, respectively (FIGS. 3 and 4 show examples of a shadow mask).
White pins 3a and 3b are generated at the periphery of the large diameter hole or the periphery of the small diameter hole of the fine through holes 2a and 2b formed in the metal sheet 1.
As a result, the product yield of the shadow mask and the aperture grill is reduced.

The present invention has been made in view of the above-mentioned circumstances, and further cleans the surface of a thin metal plate before the formation of a photoresist film, thereby eliminating the remaining adhesion of contaminants. An object of the present invention is to provide a metal sheet cleaning apparatus and a metal sheet cleaning method capable of reducing the occurrence of a product defect called a white pin and improving the product yield of a shadow mask and an aperture grill.

[0009]

According to the first aspect of the present invention, there is provided an apparatus for cleaning a thin metal plate which is a shadow mask plate or an aperture grill plate, comprising a degreasing tank and a washing tank, wherein the metal carried out of the washing tank is provided. Immerse thin plate in electrolyte
An electrolytic cleaning tank for electrolysis cleaned by soaked, the electrolytic solution contained in the electrolytic cleaning tank, phase disposed on the carry-out side of the sheet metal
The hand electrode and the electrode potential of the metal sheet are negatively polarized and the electrolyte
Bubbles are generated from the surface of a sheet metal immersed in
Voltage is applied between the counter electrode and the metal sheet.
Voltage applying means. Invention according to claim 2
Is characterized in that, in the cleaning apparatus according to the first aspect, a shower rinsing tank for rinsing the metal sheet conveyed from the electrolytic cleaning tank is provided . The invention according to claim 3 provides a shadow
Metal sheet which is mask plate or aperture grill plate
After degreased and washed with water, the photo
Before forming a resist film, clean the surface of the metal sheet.
In the method of cleaning metal sheets to be treated,
While immersing the thin metal sheet in the electrolytic solution for electrolytic cleaning,
The electrode potential of the metal sheet is negatively polarized and water
Hydrogen bubbles are generated, and the hydrogen bubbles cause the surface of the metal sheet
Is washed by stirring.

[0010]

In the apparatus for cleaning a metal sheet according to the first aspect of the present invention, the metal sheet degreased in the degreasing tank and washed in the water washing tank is further subjected to electrolytic cleaning in an electrolytic cleaning tank that is cleaner than the degreasing tank. As a result, contaminants that have entered the concave portion of the dull on the surface of the metal sheet are sufficiently removed. Also, the mating electrode is disposed on the metal sheet discharge side of the electrolytic cleaning tank, the voltage
A voltage is applied between the counter electrode and the metal sheet by the application means.
Since by the electrode potential of the metal sheet is cathodic polarization, in the vicinity of the liquid surface of the sheet metal carry-out side, the surface of the sheet metal is agitated washed with bubble hydrogen that with the water electrolysis occurs at the surface of the sheet metal You. This prevents the contaminants removed from the surface of the metal sheet in the electrolytic cleaning tank and diffused into the electrolytic solution, thereby preventing the contaminants floating in the electrolytic solution from re-adhering to the surface of the metal sheet. When a metal sheet is subjected to anodic polarization electrolysis,
Oxygen bubbles generated on the surface of the sheet cause the surface of the sheet metal
Oxidized and rusted, shadow masks and apertures
This cleaning equipment can cause
Rust is generated on the surface of the metal sheet because the sheet metal is anodically polarized.
There is no need to worry that it will be produced and cause product failure. Contract
In the cleaning apparatus according to the second aspect of the present invention, the metal sheet conveyed from the electrolytic cleaning tank is washed with a shower water washing tank.
Electrolyte and contaminants remaining on the surface of the sheet metal are completely washed away. Metal sheet of the invention according to claim 3
According to the washing method, the degreased and washed metal sheet is
Perform further electrolytic cleaning in an electrolytic solution that is cleaner than the degreasing solution.
So that it goes deep into the concave of the dal on the surface of the metal sheet
Contaminants are sufficiently removed. Also, during electrolytic cleaning
In addition, the electrode potential of the metal sheet
Hydrogen bubbles are generated, and the hydrogen bubbles
Since the surface is agitated and cleaned, it is removed from the surface of the sheet metal.
Pollutants that are diffused into the electrolyte and suspended in the electrolyte
Is prevented from re-adhering to the surface of the sheet metal. Further
In addition, since the sheet metal is anodically polarized, the surface of the sheet metal
Oxidized and rusted, causing shadow masks and apertures
There is no worry that Lil will cause product failure.

[0011]

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

FIG. 1 shows an embodiment of the present invention, and is a schematic view showing a schematic configuration of an entire apparatus for cleaning a thin metal plate. FIG. 2 shows a configuration of an electrolytic cleaning tank constituting a part of the cleaning apparatus. It is a schematic diagram showing one example of.

The apparatus for cleaning a thin metal plate is provided in front of the photosensitive liquid coating apparatus, and as shown in FIG.
It is composed of a first shower rinsing tank 12, an electrolytic cleaning tank 14, and a second shower rinsing tank 16, which are formed of a long strip-shaped metal sheet 18 which is a shadow mask plate or an aperture grill plate.
In the transport direction. The degreasing tank 10 and the first shower rinsing tank 12 are the same as the conventional cleaning apparatus, and detailed description thereof is omitted. However, the degreasing tank 10 includes, for example, sodium silicate, a surfactant, and the like therein. The contained degreasing liquid 20 is accommodated, and the metal sheet 18 is guided into the degreasing liquid 20, the metal sheet 18 is transported while being immersed in the degreasing liquid 20, and then the metal sheet 18 is led out of the degreasing liquid 20. A transport roller 22 is provided, and near the outlet of the degreasing tank 10, a liquid removal roller 24 for preventing the degreasing liquid 20 from being taken out of the degreasing tank 10 by the thin metal plate 18 is disposed. Note that electrolytic degreasing may be performed in the degreasing tank 10 to increase the degreasing power. In addition, the first shower rinsing tank 12 has transport rollers 26.
A number of shower nozzles 28 are disposed so as to face the metal sheet 18 conveyed in the shower rinsing tank 12 by the metal sheet 18 near the outlet of the first shower rinsing tank 12. A draining roller 30 for preventing the washing water from being brought into the electrolytic cleaning tank 14 to prevent the concentration of the electrolytic solution from decreasing.
Are arranged.

The electrolytic cleaning tank 14 contains an electrolytic solution 32 such as caustic soda. The metal sheet 18 is guided into the electrolytic solution 32 and transported while the metal sheet 18 is immersed in the electrolytic solution 32. A transport roller 34 for guiding the metal sheet 18 out of the electrolyte 32 is provided. In addition, near the outlet of the electrolytic cleaning tank 14, a liquid removal roller 36 for preventing the electrolytic solution 32 from being taken out of the electrolytic cleaning tank 14 by the thin metal plate 18 is provided. And the electrolytic cleaning tank 14
As shown in FIG. 2, the metal sheet 1 in the electrolytic solution 32 is
The counter electrode (counter electrode) 3 is provided on the carry-in side and carry-out side 8 respectively.
Reference numerals 8 and 40 are provided, and a reference electrode (for example, an Ag / AgCl electrode) 42 is provided on the carry-in side of the metal sheet 18. The counter electrodes 38 and 40 are formed by, for example, plating a platinum (Pt) on a titanium (Ti) substrate. Each of the counter electrodes 38 and 40 is respectively connected to an external DC power supply (for example, a rectifier, a DC stabilized power supply). , Constant potential electrolyzer, etc.) 44 and 46 are electrically connected to the anode terminals. So
And placed on the unloading side of the metal sheet 18 in the electrolytic solution 32.
Between the opposing electrode 40 and the thin metal plate 18
18 to the external DC power supply 46 so that the electrode potential
Therefore, a voltage is applied. The comparison electrode 42 is electrically connected to a cathode terminal of a potentiometer 48 such as an electrometer. Then, one end of each of the conductors 50 and 52 is connected to the cathode terminal of each of the external DC power supplies 44 and 46, and the other end of each of the conductors 50 and 52 is wound around the metal thin plate 18, respectively. The transfer rollers 34a and 34b, which are made of metal, are electrically brought into sliding contact with each other. In addition, one end of the conducting wire 54 is connected to the anode terminal of the potentiometer 48, and the other end of the conducting wire 54 is brought into electrical contact with the metal transport roller 34a in a sliding state. The transport rollers 34a, 34b are formed of a material other than metal, and the other ends of the conductive wires 50, 52, 54 are brought into electrical contact with a part of the moving thin metal plate 18 in a sliding state. You may. Instead of an external DC power supply, an AC or pulse power supply may be used as the external power supply.

A plurality of shower nozzles 58 are provided in the second shower rinsing tank 16 disposed after the electrolytic cleaning tank 14 so as to face the metal sheet 18 conveyed in the shower rinsing tank 16 by the conveying rollers 56. In the second shower tub 16, the electrolyte and contaminants remaining on the surface of the thin metal plate 18 are almost completely washed away with water.

In the cleaning apparatus having the above-described structure, when a thin metal plate 18 that has been degreased in the degreasing tank 10 and then rinsed in the rinsing tank 12 is transported to the electrolytic cleaning tank 14 in the same manner as in the prior art, Since the water electrolysis is performed in the electrolytic solution 32 which is in a cleaner state than the degreasing solution 20, the electrolytic cleaning can be performed more efficiently than when the electrolysis is performed only in the degreasing solution. As a result, contaminants such as oil and metal powder, which cannot be sufficiently removed from the surface of the metal sheet 18 by the degreasing tank 10 and the washing tank 12 alone, particularly fine contaminants that enter the deep part of the dull recess are separated and removed. Will be done. The electrolytic cleaning tank 14 is provided after the degreasing tank 10 and the water rinsing tank 12, and since the electrolytic solution 32 is kept relatively clean, the potential control can be easily performed.

Further, in the electrolytic cleaning tank 14, a counter electrode 40 is arranged on the carry-out side of the metal sheet 18, and the metal sheet 1
Since the electrode potential of 8 are allowed to cathodic polarization, in the vicinity of the liquid surface of the sheet metal carry-out side, the surface of the metal sheet 18 is agitated washed with bubble hydrogen that with the water electrolysis occurs at the surface of the sheet metal 18 As a result, contaminants removed from the surface of the metal sheet 18 and diffused into the electrolytic solution 32 and floating in the electrolytic solution 32 are prevented from reattaching to the surface of the metal sheet 18. Here, hydrogen bubbles are generated from the surface of the metal sheet 18.
To the electrode potential of the metal sheet 18 by cathodic polarization by the external DC power supply 46 to be lowered until hydrogen evolution potential. For example, if the electrolytic solution 32 in the electrolytic cleaning tank 14 is an alkaline solution and has a pH of 14 to 15, the hydrogen generation potential at that pH is expressed by a Pourbaix D (Pourbaix D) diagram.
iagram) and the Nernst equation (E = −0.059)
pH), -0.83 Vvs. NHE (standard hydrogen electrode potential) (at pH = 14) and -0.89 V vs. N
HE (at pH = 15). Therefore, the metal sheet 1
The voltage may be applied by the external DC power supply 46 while monitoring with the potentiometer 48 connected to the comparison electrode 42 so that the electrode potentials of the electrodes 8 are equal to or lower than the hydrogen generation potential .

[0018]

According to the first aspect of the present invention, there is provided the cleaning apparatus according to the first aspect.
Further, according to the cleaning method of the present invention , the metal sheet which is the shadow mask plate material or the aperture grill plate material is cleaned at the stage before the formation of the photoresist film, so that the surface of the metal sheet can be cleaned. Since the contaminants can be separated and removed almost completely, the occurrence of product defects such as white pins , which has occurred conventionally, is reduced, and the product yield of shadow masks and aperture grills is improved. When the cleaning device of the invention according to claim 2 is used, metal
Completely remove electrolyte and contaminants remaining on the surface of the thin plate
The surface of the metal sheet
It is cleaned.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of an entire thin metal plate cleaning apparatus according to one embodiment of the present invention.

FIG. 2 is a schematic view showing an example of a configuration of an electrolytic cleaning tank constituting a part of the cleaning apparatus.

FIG. 3 is a view for explaining a problem when cleaning a thin metal plate using a conventional cleaning apparatus, and is a partially enlarged longitudinal sectional view of a shadow mask.

FIG. 4 is a partially enlarged plan view of the shadow mask shown in FIG. 3 as viewed from a lower surface side (a side on which a large-diameter hole is formed).

[Explanation of symbols]

10 Degreasing tank 12 First shower rinsing tank 14 Electrolytic cleaning tank 16 Second shower rinsing tank 18 Long strip-shaped metal sheet which is a shadow mask plate material or an aperture grill plate material 20 Degreasing solution 22, 26, 34, 56 Transport roller 28, 58 Shower nozzle 32 Electrolyte 40 Counter electrode 46 External DC power supply 52 Conductor

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hitoshi Yamanaka 480-1, Takamiya-cho, Hikone City, Shiga Prefecture Dainippon Screen Manufacturing Co., Ltd. Hikone District Office (72) Inventor Hiroshi Nishimuta 480 Takamiyacho, Hikone City, Shiga Prefecture No. 1 Dainippon Screen Manufacturing Co., Ltd. Hikone area office (56) References JP-A-1-36800 (JP, A) JP-A-4-176899 (JP, A) (58) Fields surveyed (Int .Cl. ⁷ , DB name) C25F 7/00

Claims (3)

(57) [Claims] 1. A degreasing tank for removing oils and fats adhering to the surface of a thin metal plate which is a shadow mask plate material or an aperture grill plate material, and a washing tank for washing the thin metal plate conveyed from the degreasing tank with a metal. In a metal sheet cleaning apparatus for cleaning a surface of a metal sheet before forming a photoresist film on the surface of the sheet, the metal sheet conveyed from the washing tank is immersed in an electrolytic solution.
An electrolytic cleaning tank for electrolysis cleaned by immersed, housed in electrolytic cleaning tank in the electrolyte, and the mating electrode disposed on the carry-out side of the sheet metal, the electrolyte electrode potential of the metal thin plate by cathodic polarization Immersed in
So that hydrogen bubbles are generated from the surface of the
Applying a voltage between the partner electrode and the metal sheet
Means for cleaning a thin metal plate. 2. The metal sheet cleaning apparatus according to claim 1, further comprising a shower rinsing tank for rinsing the metal sheet transported from the electrolytic cleaning tank. 3. A shadow mask plate or aperture grille.
After degreasing and washing the thin metal plate
Before forming the photoresist film on the surface of the metal sheet,
Metal sheet cleaning method that cleans the surface of the sheet
hand, The degreased and washed metal sheet is immersed in
The metal potential is negatively polarized while the metal plate is
Hydrogen bubbles are generated from the surface of the sheet, and the hydrogen bubbles
Characterized in that the surface of a thin metal plate is washed by stirring.
How to clean thin plates.