JP3009076B2 - Method for forming fine holes in metal sheet - 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 forming a fine through-hole in a thin metal sheet by etching the thin metal sheet from both sides thereof, for example, a color CRT (Cathode).
It is used for manufacturing shadow masks and aperture grills for (Ray Tube).

[0002]

2. Description of the Related Art As shown in FIG. 18, a color CRT has an electron gun 30 for emitting three electron beams B, and a fluorescent light for emitting three primary colors upon receiving the electron beam B emitted from the electron gun 30. The body 31 is disposed between the phosphor 31 and the electron gun 30 to selectively pass only the electron beam in a required direction among the electron beams B to block an electron beam in an unnecessary direction. Mask 32 with a large number of through holes
It is comprised including.

As shown in FIG. 19, a Trinitron (registered trademark owned by Sony Corporation) type color CRT includes an electron gun 50 provided in a glass tube 53 and a phosphor 51 on the front surface of the glass tube 53. And an aperture grill 52 arranged in close proximity. The aperture grill 52 is shown in FIG.
As shown in FIG. 0, only the electron beam in a desired direction among the three electron beams B emitted from the electron gun 50 is transmitted through the slit 54, and is made of a thin metal plate on which a number of slits 54 are formed. The electron beam in the direction is caused to collide with the metal portion 55 so as not to reach the phosphor 51.

In recent years, color CRTs have been widely used in addition to general color television picture tubes for receiving television broadcasts.
It has been widely used for displays and monitors of computers and the like. With such diversification of uses, there is a strong demand for color CRTs with extremely high definition image quality. For this reason, shadow masks and aperture grills used in color CRTs (hereinafter, referred to as “high-resolution CRTs”) used for displays and monitors have fine holes and slits that are not irregular in shape. Is required.

Here, a shadow mask is generally used as shown in FIG.
It is manufactured through the steps shown in FIG. That is, low carbon aluminum killed steel having a thickness of about 0.1 to 0.3 mm or an Invar alloy (iron-nickel alloy having a nickel content of 36%) is used as a shadow mask material. After the surface of the material is degreased and washed with water, a photosensitive liquid is applied to both surfaces of the shadow mask material and dried, and a photoresist film having a thickness of several μm is formed on both surfaces of the shadow mask material. Next, an exposure mask having a pattern image corresponding to the electron beam passage hole to be formed is brought into close contact with the surface of each of the photoresist films on both sides of the shadow mask material so that the image positions are aligned on the front and back sides. After exposure through each of the masks, development and subsequent hardening are performed, thereby forming a corrosion-resistant film (resist film) of a pattern image on each of the front and back surfaces of the shadow mask material. Then, spray etching is performed using an aqueous ferric chloride solution to corrode the exposed metal parts without being covered with the resist film, thereby forming a large number of through holes of a desired shape in the plate material, and performing etching. After the end, the resist film is peeled off from the front and back surfaces of the plate, washed with water and dried,
The plate material is cut into a predetermined shape to obtain a desired shadow mask.

In a shadow mask for a high-resolution CRT, the diameter of the through hole is often smaller than the thickness of the shadow mask material.
When manufacturing by a method of forming a through hole by one etching, it is extremely difficult to form a through hole in a desired design shape, and it has been experienced that only a shadow mask that cannot be used practically can be obtained. Is known.

As one of the measures, for example, USP.
No. 3,679,500 and Japanese Patent Publication No. 57-26345 disclose a method of performing etching stepwise in two divided steps. This method is described in FIGS.
This will be described with reference to FIG.

As shown in FIG. 22A, a thin metal plate (shadow mask material) 1 on which resist films 2 and 2 'of a pattern image are respectively formed on both front and rear surfaces is formed.
As shown in FIG. 22 (b), an etching solution (ferric chloride aqueous solution) 4 is sprayed on one side of the metal sheet 1 from the spray nozzle 3, or as shown in FIG. 'Etching solution (ferric chloride aqueous solution)
4 is sprayed on both surfaces of the metal thin plate 1 to perform the first etching. The etching is temporarily stopped at a stage before the through-hole is formed in the metal thin plate 1, and is washed with water and dried to obtain FIG. As shown in FIG. 22, fine concave portions 5 are formed on one side of the metal sheet 1, or fine concave portions 5, 5 'are formed on both sides of the metal sheet 1 as shown in FIG. I do. Then, when etching is performed on one side, FIG.
As shown in (d), the etched surface is covered with the etching resistance layer 6, and when both surfaces are etched, one of the surfaces is covered with the etching resistance layer 6 as shown in FIG. I do. In order to form the etching resistance layer 6, paraffin, asphalt, lacquer, UV resin, or the like is applied to the entire surface of the thin metal plate 1 including the surface of the resist film 2 by spraying, a roll coater, or the like. Next, FIG.
As shown in FIG. 23 (e ′), the etching liquid 4 is sprayed from the spray nozzle 3 ′ onto the side not covered with the etching resistance layer 6 on the metal sheet 1 to perform a second etching, and FIG. (F '), the fine concave portion 7 (5') formed on one side and the fine concave portion 5 on the other side are communicated with each other. After completion of the etching, the etching resistance layer 6 and the resist films 2 and 2 ′ are respectively peeled off from the surface of the metal thin plate 1, washed with water, and dried to penetrate the front and back as shown in FIG. 23 (g). The metal sheet 1 in which the fine through holes 8 are formed is obtained.

However, in the above-described method, at the time of the first etching, the peripheral portion of the fine concave portion extends to the peripheral portion of the opening portion on the lower surface of the resist film by side etching (FIGS. 22C and 22C). )), FIG. 2
As shown in FIG. 4, the resist film 2 slightly protrudes from the periphery of the fine concave portion 5 toward the center of the concave portion 5. For this reason,
In the step of covering one side of the metal thin plate 1 with the etching resistance layer 6, the overhanging portion of the resist film 2 (hereinafter referred to as "eave")
An air pocket 10 as shown in FIG. Since the surface of the metal sheet 1 in the air pocket 10 is not covered with the etching resistance layer 6, the fine recess formed on the surface that is not on the etching side as shown in FIG. Etching up to the inner surface of the cavity 5 causes the microcavity 5 to widen greatly, so that it is not possible to finally form a fine through-hole having a desired shape, resulting in a defect in the shadow mask. There is. The manufacturing process of the aperture grill is basically the same as the manufacturing process of the shadow mask described above, and the manufacturing of the aperture grill has the same problems as those in the manufacturing of the shadow mask.

As a method for solving such a problem,
JP-A-59-73834 discloses that after a first etching step, a resist film on a surface on which an etching resistance layer is to be formed is removed from the surface of the metal sheet, and then the resist film is removed from the surface on which the resist film has been removed. A method for forming an etching resistance layer is disclosed. Also, Japanese Patent Application Laid-Open No. 61-1
Japanese Patent No. 30492 discloses that after the first etching step,
A method is disclosed in which only the eaves portion of the resist film is removed by immersing the entire metal sheet in an ultrasonic bath by ultrasonic waves, and then forming an etching resistance layer.

[0011]

However, in the method disclosed in JP-A-59-73834, when the resist film is removed after the first etching step, the resist film on the opposite side is simultaneously removed. In order not to be removed, the resist film on the opposite side must be protected by a sheet or the like.
It is necessary to prepare a protective sheet, and a sheet sticking and peeling device is required. Furthermore, when the resist film is removed by spraying with an alkaline solution or the like, a cleaning device is required in addition to the resist film removing device, which complicates the configuration of the entire shadow mask manufacturing apparatus. There is.

On the other hand, in the method disclosed in Japanese Patent Application Laid-Open No. Sho 61-130492, after the first etching, a small amount of the etching solution remains in the fine concave portions formed on the metal sheet, and the ordinary etching solution is used. Since it is very difficult to completely remove the remaining etchant by cleaning, when the metal sheet is immersed in the ultrasonic bath, the fine recesses are corroded by the residual etchant in the ultrasonic bath. There is a problem that it spreads. Further, when ultrasonic waves are applied to the metal thin plate to such an extent that the eaves of the resist film can be cut off, the ultrasonic waves cause poor adhesion between the metal thin plate and the resist film, and the second etching step does not include a portion other than a desired portion. There is a problem that etching occurs and causes a defect on the shadow mask.

[0013] The present invention has been made in view of the circumstances as described above, without the need for complex equipment and processes, and, without using an ultrasonic bath, the eaves part of Les resist film It is a technical problem to provide a method that can be removed.

[0014]

According to the present invention, as a means for solving the above-mentioned problems, there is provided a method for etching a thin metal plate from both sides thereof, wherein the etching is performed stepwise in two steps. one side of the sheet metal after the first etching step, including the surface of the resist film after covered with etch resistant layer, to perform the second etching step, the table of the sheet metal after the second etching step
Separate the etching resistance layer and resist film from the surface
Away to a method for forming fine holes in sheet metal, prior to the coating step of the etch resistant layer on one surface side of the metal sheet to be coated by etching the resistive layer,
Blown to the sheet metal surface fluid as a high pressure jet stream, the record of the overhanging portion from the periphery of the fine crypts portion to crypts section center direction caused by the first etching step
A step of removing the eaves of the distant film by breaking the eaves from the base of the eaves by the impact force of the jet flow ;
Rinse with water to remove resist film slices removed in the removal process
And a process .

In the method for forming fine holes in a metal sheet having the above-described structure, after the first etching step and before the step of coating the etching resistance layer, one side of the metal sheet on which the etching resistance layer is to be formed is formed. A high-pressure fluid is sprayed as a jet flow using a high-pressure spray nozzle or the like. In this case, the eaves portion of the resist film formed on the peripheral portion of the fine concave portion of the metal sheet formed by the first etching step is not joined to the metal sheet like other portions of the resist film. Since there is no support, the resist film is broken around the root of the eave by the physical impact force of the jet flow of the high-pressure fluid, and the resist film around the root of the eave is removed. And the excised resist film
Are removed from the sheet metal by the washing step.
Accordingly, in the subsequent step of coating the etching resistance layer, air does not remain as in the related art,
Since one side of the metal sheet is completely covered with the etching resistance layer including the surface of the resist film, the inner surface of the fine concave portion formed on the non-etching side is etched during the second etching. Disappears.

As described above, according to the present invention, the water pressure in the water washing step, which is conventionally performed as a post-etching step, is reduced by partially peeling off the resist film or causing a crack in the resist film to partially adhere to the thin metal plate. To prevent defects,
Furthermore, in order to prevent the metal sheet itself from being broken, the fixed idea that the pressure must be suppressed to a low pressure, for example, 0.5 to 1.5 kgf / cm ² , has been removed. This led to the idea that the eaves could be removed, and this was completed by confirming this through experiments.

[0017]

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

The method for forming fine holes in a thin metal plate according to the present invention is basically the same as the generally performed method in passing through each of the steps described above with reference to FIGS. According to the method of the present invention, the first etching step (FIG. 22B, FIG. 22C or FIG.
(C ')) after the end of the process of coating the etching resistant layer (FIG. 22 (d) or (d' prior to)), Les resist film formed on the peripheral portion of the fine crypts portion 5 thin metal sheet 1 Eaves 9 (Fig. 2
4) (hereinafter referred to as “eave removal”).

The jet flow of the high-pressure fluid using a high-pressure spray nozzle or the like is to be sprayed uniformly over one side of the thin metal plate on which the etching resistance layer is to be formed. For this purpose, as shown in FIGS. 1 (a) to 1 (c), one or a plurality of high-pressure spray nozzles 11 are relatively moved in parallel with the surface of the metal sheet 1, and the entire surface of one side of the metal sheet 1 is moved. Scanning may be performed, or a plurality of high-pressure spray nozzles may be arranged in a row and fixed so that the ejected flow of the fluid strikes the entire surface of one side of the metal sheet without leakage.

The fluid to be used may be any fluid that can be ejected from a high-pressure spray nozzle and that can give a physical impact to the resist film by the ejected flow, such as water, acid, alkaline water, and various chemicals. Liquids such as organic solvents, powders such as ice particles, sand, titanium oxide powder and quartz powder, or mixtures of these liquids and powders are used.

The above steps are performed after the first etching and before the drying step before forming the etching resistance layer.
What is necessary is just to implement by an appropriate method. For example, after the first etching and after the washing step, the eaves may be removed (as an independent step). In this case, since the surface of the metal sheet has been cleaned by the washing step, it can be repeatedly used by circulating jet water or the like. After the first etching, the eaves may be removed also as a washing step. In this case, since the eaves are removed simultaneously using the spray water from the spray nozzle of the water washing device, a dedicated device only for removing the eaves is not required. Then, following the eaves removing step, a section of the resist film cut off by a water washing step is subjected to gold plating.
Eliminate from the plate .

In the experiment, the web-shaped shadow mask material was not deformed even by the water pressure at the time of injection of the high-pressure water. However, for safety, a metal thin plate was supported on a stage and its upper surface was moved. Alternatively, high-pressure water or the like may be sprayed onto the upper surface of the sheet metal, or high-pressure water or the like may be sprayed onto a portion supported by the roll while moving the web-shaped sheet metal around a rotating roll. .

Next, experiments to which the present invention is actually applied and their results will be described with reference to FIGS. 2 to 10 and Table 1.

As a sample, a web-shaped shadow mask material 14 (low-carbon aluminum killed steel) was formed by forming round hole recesses having a hole diameter of about 100 μm on both sides after the first etching step and then performing washing and drying. As shown in FIG. 2, the shadow mask material 14 is transported along the upper surface of a surface plate stage (not shown), and the high-pressure fluid spraying system 18 is transported by the shadow mask material 14 as shown in FIG. In the direction perpendicular to the direction and the shadow mask material 14
The liquid was moved along the guide 19 in parallel with the upper surface of the shadow mask material 14 so that the fluid was uniformly sprayed over the entire surface of the shadow mask material 14 from the spray system 18 moving in the width direction of the shadow mask material 14.

The spray system 18 for injecting the high-pressure fluid is an A7A airless automatic gun manufactured by Nordson Corp., and the fluid to be injected is room temperature water at 23.2 ° C. It was about 2 mmφ. The conveying speed of the shadow mask material 14 is 1 mm / sec, the moving speed of the spray system 18 is 400 mm / sec,
The width of 4 was 600 mm. Then, while changing the spray pressure of the spray system 18 as shown in Table 1, 2 cm from the surface of the shadow mask material 14 for each pressure.
The experiment was conducted by injecting room-temperature water vertically from the separated height. The spray pressure was measured using Fuji Film Co., Ltd.
The test was performed using Fujifilm Prescale for ultra-low pressure (two-sheet type).

Next, as described above, the surface of one side of the shadow mask material 14, which has been subjected to the first etching process of the high-pressure fluid after being subjected to the high-pressure fluid spraying process, has a plurality of recesses formed thereon. About 1,000 cP UV as a layer
The resin was applied to a thickness of about 10 μm by a roll coater.

Subsequently, as shown in FIG. 23, an etching solution is sprayed from a spray nozzle to one side not covered with the etching resistance layer, and a second etching is performed to form an etching solution on the one side. The fine concave portion formed in the first etching step and the fine concave portion formed in the first etching step are communicated with each other. Thereafter, the etching resistance layer and the etching resistive layer and the The resist films were respectively stripped, washed with water and dried. In the first and second etching steps, an aqueous ferric chloride solution at 40 ° C. and 45 degrees Baume was used.

As a method of evaluating the experimental results, regarding the effect of removing the eaves, the surface of the shadow mask material 14 after the room-temperature water spraying step by the spray system 18 was observed with an optical microscope to determine whether the eaves were completely removed. It was determined whether or not. FIG. 3 is an electron micrograph at 100 × magnification of the surface of the shadow mask material 14 on which a plurality of concave portions are formed before the eaves removing step, and FIG. 4 is a shadow mask removed from the eaves through the eaves removing step. It is also an electron micrograph of the surface of the material 14 at 100 times. FIG. 5 is a 500 × electron micrograph of the surface of the shadow mask material 14 before the eaves removing step, and FIGS. 6 and 7.
Is a 500-fold electron microscope photograph of the surface of the shadow mask material 14 in the middle of the eaves removing step, and FIG. 8 is a 400-fold electron microscope photograph of the surface of the shadow mask material 14 in the final stage of the eaves removing step. 9 and 10 respectively show
It is a photograph of 500 times and 2,500 times the surface of the shadow mask material 14 after the eaves removing step. From FIGS. 9 and 10,
It can be seen that not only the eaves formed by the first etching step but also the surrounding resist film centered on the root eaves is slightly removed.

Regarding the presence or absence of air pockets, the coating state on the surface of the shadow mask material 14 coated with the UV resin after the eaves removing step by the high pressure fluid spraying spray system 18 as described above is observed with an optical microscope. It was determined whether any air pockets existed.

Further, the finished state of the etching is finally formed on the shadow mask material 14 through the steps of eaves removal, etching resistance coating, second etching, removal of the resist film and the etching resistance layer, washing and drying. The obtained fine through-hole was visually determined, and it was determined whether or not the fine through-hole was formed in a desired shape. Table 1 shows the results of these determinations.

[0031]

[Table 1]

According to the above experimental results, the spray pressure of the spray system 18 for injecting a high-pressure fluid was set to 10 kgf / cm ² or more,
For example, by setting it to 15 kgf / cm ² , the eaves are completely removed, so that even if the etching resistance layer is covered, there is no air pocket and finally a fine through hole having a desired shape is formed. I understand.

Next, several examples of a method of executing a step of injecting a high-pressure fluid onto the surface of a thin metal plate, which can satisfy the eaves removal conditions clarified by the above experimental results, will be described.

First, in the example shown in FIG. 11, the web-shaped shadow mask material 14 after the first etching step is transported along the upper surface of a platen stage (not shown),
Provide 3 spray nozzles 48 and use them as shadow mask material
The three spray nozzles that move along the guide 19 in a direction perpendicular to the transport direction of 14 and in parallel with the upper surface of the shadow mask material 14 and move in the width direction of the shadow mask material 14
The configuration is such that the fluid is uniformly sprayed from 48 to the entire surface of the shadow mask material 14.

As the spray nozzle 48, 1/4 MVEP11519 manufactured by Ikeuchi Co., Ltd. was used. This spray nozzle 48 is 7 cm from the surface of the shadow mask material 14.
Approximately 8 in the conveying direction of the shadow mask material 14 from the height
The effluent is blown in a fan shape in the range of cm.
Room temperature water is used as the fluid to be jetted, the conveying speed of the shadow mask material 14 is 3 m / min, and the moving speed of each spray nozzle 48 is 250 mm / sec or more, for example, 300 mm.
/ Sec at 200 mm in the width direction of the shadow mask material 14
Move back and forth. The width of the shadow mask material 14 is 600 mm. At this time, 10kgf / c
m ² or more, the fluid can be injected at a spray pressure of, for example, 15 kgf / cm ^2.

Next, in the example shown in FIG. 12, a spray pipe 15 is arranged in a direction perpendicular to the conveying direction of the web-shaped shadow mask material 14 conveyed after the first etching step. The fluid is uniformly sprayed over the entire width of the shadow mask material 14 from the plurality of fixed nozzles 16 provided in a row in the pipe 15. At this time,
Room temperature water is used as the fluid to be sprayed, and the spray pressure applied to the surface of the shadow mask material 14 is 10 kgf.
/ Cm ² or more, for example, 15 kgf / cm ^2, and the conveying speed of the shadow mask material 14 is appropriately set to, for example, 0.5 to 4 as needed.
m / min. Then, a platen stage (not shown) is provided on the transfer path to support the back side of the shadow mask member 14, and the shadow mask member 14 is transferred along the upper surface of the platen stage.

Further, FIG. 13 shows that a rotating roller 17 is provided in the conveyance path in place of the platen stage in order to support the back surface side of the shadow mask material 14, and the portion supported by the rotating roller 17 is cooled to room temperature. This is an example in which water is injected. As the rotating roller 17, either a rubber-coated roller or a metal roller may be used. The spray pressure and the transport speed of the shadow mask material 14 are set to the same conditions as described above.

In each case described above, good results were obtained.

In the above-described experimental example and the embodiment of the high-pressure fluid injection step, the case of a round hole-shaped concave portion has been described. However, the present invention is not limited to this shape, and the present invention is not limited to this shape. It goes without saying that the present invention can also be applied to the case where the mold through hole is formed in the shadow mask material.

In the above-described embodiment, an example in which the present invention is applied to the case of manufacturing a shadow mask for a color CRT has been described. However, the present invention is applicable to a case where a large number of minute slits of an aperture grill are formed. The same can be applied to. Here, the manufacturing process of the aperture grill is basically the same as the manufacturing process of the shadow mask, and the pattern image of the exposure mask used when forming the slits of the aperture grill is used for forming the through holes of the shadow mask. Therefore, the description of the slit forming step of the aperture grill is omitted.

FIGS. 14 to 17 are micrographs showing the results of an experiment in which the present invention was applied to the formation of slits in an aperture grill.

FIG. 14 shows a magnification of 100 in which the surface of the thin plate before the eaves removing step was photographed, in which a plurality of elongated grooves were formed on one side of the thin metal plate by the first etching step.
FIG. 15 is an electron micrograph at × 500 magnification. The thickness of the metal sheet was 0.1 mm, and the width of the groove formed in the metal sheet was about 65 μm. On the other hand, FIG. 16 shows FIGS. 14 and 15 by the method according to the present invention.
1 of the sheet material surface after treating the surface of the metal sheet shown in
17 is an electron micrograph at × 00, and FIG.
It is an electron micrograph of the magnification.

As can be seen by comparing FIGS. 14 and 15 with FIGS. 16 and 17, in the sheet metal material processed by the method according to the present invention, the resist film projecting toward the center of the groove along both sides of the groove. The eaves have been removed. Actually, when an aperture grill was manufactured in accordance with the method according to the present invention, a good quality grill having no variation in the shape of the slit could be obtained.

Further, the present invention is not limited to the application to the manufacture of shadow masks and aperture grills for color CRTs. For example, precision electronic devices such as lead frames for electrically connecting semiconductor elements to the outside. It goes without saying that the present invention can also be applied to an etching perforation process in the production of components.

[0045]

Since the present invention is constructed and operates as described above, the metal sheet is etched from both sides, and the etching is divided into two times, and one side of the metal sheet is removed after the first etching step. When performing the second etching step after covering with the etching resistance layer, according to the method for forming fine through holes in a metal sheet according to the present invention, it is possible to prevent a surface other than the etching side from being etched in the second etching step. Since it can be effectively prevented and a fine through-hole having a desired shape can be formed, it is possible to manufacture a high-definition shadow mask and an aperture grill having no defect. According to the method of the present invention, it is only necessary to provide relatively simple equipment for removing the eaves portion of the resist film.

[Brief description of the drawings]

FIG. 1 is a partially enlarged longitudinal sectional view for explaining the configuration and operation of a characteristic portion in a method for forming fine through holes in a thin metal plate by etching according to the present invention.

FIG. 2 shows a high-pressure fluid injection step performed in an experiment in which the present invention was actually applied.

FIG. 3

FIG. 10 is an enlarged electron micrograph showing a metal structure on the surface of a shadow mask material according to an experiment.

FIG. 11

FIG. 13 is a schematic perspective view illustrating a method of practicing the present invention.

FIG. 14

FIGS. 17A and 17B are enlarged electron micrographs showing the metallographic structure of the surface of a thin metal plate for explaining experimental results when the present invention is applied to a step of forming slits in an aperture grill.

FIG. 18 is a diagram showing a schematic configuration of a color CRT.

FIG. 19 is a view showing a schematic configuration of another type of color CRT.

20 is a partially enlarged front view of an aperture grill used in a color CRT of the type shown in FIG. 19;

FIG. 21 is a diagram illustrating an example of a manufacturing process of the shadow mask.

FIG.

FIG. 23 is a partially enlarged longitudinal sectional view for describing an etching step according to a conventional method.

FIG. 24,

FIG. 25 is a partially enlarged longitudinal sectional view for describing a problem in a conventional etching method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal thin plate 2, 2 ′ resist film 5, 5 ′ fine concave portion 6 etching resistance layer 8 micro through hole 9 resist film eaves 11 high pressure spray nozzle 12 fluid 13 resist film 14 shadow mask material 15 spray tube 16 fixed nozzle 48 spray nozzle

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kyoyoshi Miyaji 4-chome Tenjin, Horikawa-dori-Terauchi, Kamigyo-ku, Kyoto 1 Daikoku Screen Manufacturing Co., Ltd. (72) Inventor Masanobu Sato Kyoto 4-Chome Ten-Cho, Horikawa-dori-Terauchi, Kamigyo-ku, Tokyo 1 Daikoku Screen Manufacturing Co., Ltd. (72) Inventor Akihiro Inagaki 480 Takamiyacho, Hikone City, Shiga Prefecture Dainippon Screen Manufacturing Co., Ltd. In the Hikone district office (72) Inventor Shoji Tokai One at 480 Takamiya-cho, Hikone city, Shiga Prefecture Dainippon Screen Manufacturing Co., Ltd. In the Hikone district office (72) Inventor Koichi Omoto 480 Takamiyacho, Hikone city, Shiga prefecture No. 1 Dainippon Screen Manufacturing Co., Ltd. In the Hikone area business office (56) References JP-A-61-130492 (JP, A) JP-A-59-73834 (JP, A) JP-A-58-135646 (JP, A) JP-A-61-178199 (JP, A) JP-A-62-9875 (JP, A) JP-A-55-80319 (JP, A)

Claims (1)

(57) [Claims] 1. A step of forming a resist film having a pattern image corresponding to each other on both sides of a thin metal plate, and forming an exposed portion of the surface of the thin metal plate which is not covered with the resist film. Is etched from both sides or one side to form a fine recess on both sides or one side of the metal sheet; and one side of the sheet metal on which the fine recesses are formed ,
A step of coating with a resistive etching layer including the surface of the resist film; and etching the metal thin plate from one side not covered with the resistive etching layer, and the fine pits from one side to the other side. a second etching step of forming a through-going micro-holes to part from the surface of the metal sheet after the second etching step
Separate the etching resistance layer and resist film respectively
In the method of forming fine holes in a metal sheet, prior to the step of coating the etching resistance layer, on one side of the metal sheet to be covered by the etching resistance layer,
A high-pressure fluid is sprayed onto the surface of the thin metal plate as a jet flow, and the eaves of the resist film at the portion protruding from the peripheral edge of the fine concave portion toward the center of the concave portion are caused by the impact force of the jet flow at the root portion of the eaves. Removal of eaves that break off from
Process and the resist film section removed in this eaves removal process
A method of forming fine pores in a thin metal plate, comprising :