JPH05247671A - Spray etching device - Google Patents

Abstract

PURPOSE:To uniformly and efficiently perform a highly accurate etching by always covering the whole etching surface of a metallic sheet with a less fatigued etching liquid and making the etching speed faster and uniform over the whole surface of the metallic sheet. CONSTITUTION:The fatigued etching liquid 20' remaining on the metallic sheet 12 injected from a spray nozzle is sucked by a liquid sucking means 18 to be discharged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray etching apparatus for forming fine through holes in a thin metal plate by spraying an etching solution on the surface of the thin metal plate. mask,
It is used when manufacturing electronic parts such as lead frames for semiconductor devices and printed wiring boards.

[0002]

2. Description of the Related Art A color CRT is composed of an electron gun which emits three electron beams, a phosphor which receives the electron beams emitted from the electron gun and emits light in three primary colors, and the fluorescent body and the electron gun. And a shadow mask having a large number of through holes for selectively passing only the electron beam in a necessary direction among the electron beams and blocking the electron beam in an unnecessary direction. Has been done.

The shadow mask used in the color CRT has an amber (I) containing, for example, 36% of low carbon aluminum killed steel having a plate thickness of about 0.1 to 0.3 mm and nickel.
nvar) type alloy and other shadow mask materials are formed with a large number of electron beam passage holes by a photo-etching method, and the shadow mask materials are annealed in a non-oxidizing atmosphere and press-formed in order to impart press-formability. After that, a blackening treatment is performed in an oxidizing atmosphere for the purpose of enhancing the heat radiation ability and reducing the diffused reflectivity of the electron beam, and the product is completed through the above steps.

By the way, in recent years, color CRTs have been used in addition to general color television picture tubes for receiving television broadcasting.
It has come to be widely used as a display device such as a computer and a monitor. With such diversification of applications, there is an increasing demand for color CRTs with extremely high-definition image quality. And color CR
For the shadow mask, which is one of the components of T,
It is required to have fine through holes that are uniform in size and shape.

Further, the above-mentioned circumstances also apply to lead frames for semiconductor devices and other electronic parts, which have been increasing in the number of pins in recent years, and an etching technique capable of accurately and finely processing a thin metal plate. Is required.

Here, the processing of the thin metal plate by the photoetching method, for example, the perforation processing of the shadow mask material is performed as follows. That is, first of all, after degreasing the surface of the shadow mask material, washing with water to perform surface treatment, a photosensitive solution, for example, a mixed solution of polyvinyl alcohol and ammonium dichromate is applied to both front and back surfaces of the shadow mask material, The photosensitive solution is dried to deposit a photoresist film having a thickness of several μm. Next, on the surface of each photoresist film deposited on both sides of the shadow mask material, a master pattern having a required image corresponding to the electron beam passage hole to be formed is aligned with the front and back image positions. Then, they are brought into close contact with each other and exposed. Subsequently, the film is developed using warm water, etc., and is subjected to a film hardening treatment by immersing it in a solution of chromic anhydride, followed by burning, and a corrosion-resistant film (resist film) of the required pattern image on both main surfaces of the shadow mask material. ) Are formed respectively. Then, etching is applied to both main surfaces of the shadow mask material using an aqueous ferric chloride solution to form a large number of through holes in the shadow mask material, and then the resist film is peeled from both front and back surfaces of the shadow mask material and punched. Ends.

As an etching apparatus for forming a through hole in a thin metal plate, there are a type in which a thin metal plate having a resist film formed on its surface is immersed in an etching solution, and a spray type in which an etching solution is sprayed onto the thin metal plate. There is.
Of these, in the former immersion type etching apparatus, the etching solution that corrodes the metal and is fatigued has a slow rate of diffusing from the etching surface, and a fresh solution is difficult to flow into the etching surface. , The metal is isotropically isotropically performed, and side etching progresses on the lower surface of the resist film, so that the holes are expanded,
It is not suitable for fine processing such as forming a through hole in a shadow mask. On the other hand, in the latter spray etching apparatus, in order to uniformly etch the entire etching surface, the metal thin plate is generally held horizontally and the etching solution is sprayed from the vertical direction of the metal thin plate. However, at this time, since the etching is performed while excluding the liquid fatigued by the spray pressure from the etching surface, the physical force by the spray pressure is also added, and the metal thin plate can be deeply corroded in its thickness direction, and The etching rate also becomes faster. Therefore, the through holes of the shadow mask are formed by the spray etching device.

However, even when the spray etching apparatus is used, the exhaustion of the fatigued liquid is not always sufficient by simply spraying the etching liquid on the entire surface of the metal thin plate, and the fatigued etching liquid is not removed on the metal thin plate. It will be stagnant for a long time. Then, in order to solve such a problem, for example, in Japanese Patent Publication No. 2-42905, the direction of a spray nozzle for spraying an etching solution onto the surface of a thin metal plate is changed, or the spray nozzle is provided in the length direction of the thin metal plate. By performing horizontal etching and reciprocal movement of the etching solution while changing the spray position of the etching solution, the flow state of the etching solution on the thin metal plate is improved and the fatigued etching solution is effectively removed. A spray etching apparatus is disclosed. Further, JP-A-1-204428 and JP-A-2
No. 22484, etc., a nozzle for ejecting air or an inert gas toward a thin metal plate to blow away and eliminate the fatigued etching liquid remaining on the thin metal plate, separately from a spray nozzle for ejecting the etching liquid. Disclosed is a spray etching device.

[0009]

However, in any of the spray etching apparatuses described in the above publications, not all of the fatigued etching solution is removed from the thin metal plate, and the fatigued etching solution is not removed. Part of the metal flows only on the thin metal plate to change its position, and even if the fatigued etching liquid is once removed from a certain part on the thin metal plate, the fatigued etching liquid existing immediately around it is immediately removed. Flows into that part,
There is a problem that the expected effect is not always obtained.

Further, in the above-mentioned conventional apparatus, since the exhausted etching solution is discharged more quickly as the edge of the metal thin plate is closer to the edge, the etching rate at the edge of the metal thin plate is higher than that at the center. As a result, there is a problem that uniform etching cannot be performed over the entire etched surface of the thin metal plate.

The present invention has been made in view of the above circumstances, and when spray-etching a thin metal plate, an etching solution that is fatigued from the thin metal plate is effectively removed, and the etching surface of the thin metal plate is effectively removed. The entire surface is always covered with a low-fatigue etching solution to make the etching rate fast and uniform over the entire etching surface of the thin metal plate, which enables highly accurate etching with less side etching over the entire etching surface of the thin metal plate. It is an object of the present invention to provide a spray etching apparatus that can perform uniformly and efficiently.

[0012]

A spray etching apparatus according to the present invention comprises spray means for spraying an etching solution onto the surface of a thin metal plate. Further, there is provided liquid absorbing means for sucking the fatigued etching liquid ejected from the spray means and remaining on the thin metal plate to remove it from the thin metal plate.

Preferably, a plurality of rows of spray means arranged in parallel in a direction orthogonal to the length direction of the metal thin plate and a plurality of liquid absorbing means installed so as to be orthogonal to the length direction of the metal thin plate are provided, and the spray means are provided. The columns and the liquid absorbing means are alternately arranged in the length direction of the thin metal plate.

Further, the liquid absorbing means is a liquid absorbing roller having a cylindrical shape with both end surfaces closed, and sucking the etching liquid into the inside of the cylinder through the fine pores on the outer peripheral surface of the cylinder. You may arrange | position so that an axial direction may orthogonally cross the length direction of a metal thin plate, and the cylinder outer peripheral surface may contact or adjoin the surface of a metal thin plate.

In the spray etching apparatus according to the present invention, the fatigued etching liquid ejected from the spray means and remaining on the metal thin plate is sucked by the liquid absorbing means and removed from the metal thin plate. In this way, the fatigued etching solution is forcibly removed evenly over the entire surface of the metal thin plate, so that the entire area of the metal thin plate is always covered with the fresh etching solution ejected from the spraying means. Therefore, the etching surface of the thin metal plate is uniformly etched at a high speed and with a high degree of precision with less side etching.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic structure and a flow path structure of the entire spray etching apparatus according to the present invention. Explaining the schematic configuration of this spray etching apparatus, in the etching processing chamber 10, sandwiching the transport path of the metal thin plate 12 on which a resist film of a patterned image is formed on both main surfaces, respectively, above and below the metal thin plate, 12 transport directions (metal sheet 12
Spray pipes 14 each having a plurality of spray nozzles 16 formed along the length direction) are arranged in parallel with the transport path of the thin metal plate 12. A plurality of spray pipes 14 are arranged in parallel to each other in a direction (width direction of the metal thin plate 12) orthogonal to the transport direction of the metal thin plate 12, and therefore the spray nozzles 16 are arranged in the width direction of the metal thin plate 12. A plurality of them are arranged in parallel. Further, on the upper side of the transport path of the thin metal plate 12,
A plurality of etching liquid suction hoods 18 each having a liquid suction port arranged near the upper surface of the metal thin plate 12 are arranged in the transport direction of the metal thin plate 12. The plurality of rows of spray nozzles 16 and the plurality of etching solution suction hoods 18 are alternately arranged in the transport direction of the thin metal plate 12. Further, the inner bottom of the etching processing chamber 10 serves as a liquid storage tank 22 for the etching liquid 20 ′ which has corroded the metal thin plate 12 and is fatigued.

Further, the adjustment tank 24 is provided in the etching processing chamber 10.
Is installed side by side, and the adjustment tank 24 is supplied with fresh etching liquid that has been received or regenerated, and
The fatigued etching liquid is sent from the liquid storage tank 22 or the like at any time. Then, in the adjusting tank 24, the degree of Baume, the amount of free hydrochloric acid, the degree of fatigue (ferric chloride FeCl ₃ and ferrous chloride Fe
The ratio of Cl ₂ ) and the like are adjusted, and the adjusted etching liquid 20 is fed to the spray pipes 14 and 14 of the etching processing chamber 10 by the pumps 26 and 26.

In the etching processing chamber 10, the etching solution sprayed from the spray nozzle 16 onto the surface of the metal thin plate 12 and used for corroding the metal thin plate 12 and exhausted is exhausted by the vacuum suction force of the suction pump 28. It is sent to the vacuum tank 32 through the liquid pipe 30, and the vacuum tank 32
It is temporarily stored inside. A part of the fatigued etching liquid 20 'accumulated in the vacuum tank 32 is returned to the adjustment tank 24 by the pump 34, and a part of the fatigued etching liquid 20' is etched in the liquid storage tank 22. The solution 20 'and a part of the etching solution 20 in the adjustment tank 24 are discharged out of the apparatus. The exhausted etching solution discharged from the equipment is regenerated by blowing chlorine into the solution, adding oxygen to the solution after adding hydrochloric acid, or electrolyzing the solution. Reused as a fresh etching solution.

FIG. 2 is a perspective view showing a specific structure of the etching liquid suction hood 18 for sucking and removing the fatigued etching liquid 20 'from the upper surface of the thin metal plate 12. As shown in FIG. The etching solution suction hood 18 is formed in a thin plate shape with a void inside, and the liquid suction port 36 at the lower end thereof is perpendicular to the metal thin plate 12 so as to be orthogonal to the transport direction of the metal thin plate 12. is set up. Then, the suction pump 28 is actuated to suck the inside of the etching solution suction hood 18 in vacuum, thereby making the etching solution 20 ′ fatigued on the thin metal plate 12.
Is sucked into the etching liquid suction hood 18 through the liquid suction port 36 and is removed from the thin metal plate 12.

It should be noted that the lower end of the etching liquid suction hood 18 does not come into contact with the surface of the metal thin plate 12 to prevent the metal thin plate 12 from being scratched, and the surface of the metal thin plate 12 and the liquid suction port 36 are too far apart. In order to prevent the fatigued etching solution 20 'from flowing from the etching solution suction hood 18 to the front side in the transport direction of the metal thin plate 12, as shown in FIG. Backup roller 38
Is preferably provided so that the positional relationship between the liquid suction port 36 and the upper surface of the metal thin plate 12 becomes constant. Further, as shown in FIG. 3, at a position close to the etching solution suction hood 18,
A pair of rollers 40 and 42 are rotatably arranged above and below the metal thin plate 12 so that the metal thin plate is interposed between the pair of rollers 40 and 42.
The liquid inlet 36 and the thin metal plate 12
You may make it position-adjust with the upper surface of.

FIGS. 4 and 5 are views showing another constitutional example of the liquid absorbing means for sucking and removing the fatigued etching liquid 20 'from the metal thin plate 12, and FIG. 4 shows the etching of the liquid absorbing means. FIG. 6 is a perspective view showing the liquid spraying means, and FIG. 5 is a perspective view schematically showing how the etching liquid exhausted by the liquid absorbing means is removed from the thin metal plate.

The liquid absorbing means shown in FIGS. 4 and 5 has a shape in which both end surfaces of a cylindrical body are closed, and is constituted by a liquid absorbing roller 44 having a large number of fine pores formed on the outer peripheral surface of the cylindrical body. .. The fine pores of the liquid absorbing roller 44 may be formed by forming holes on the outer peripheral surface of the cylinder. In addition, a large number of ring-shaped fibrous sheets are superposed with their respective axes aligned with each other and bonded to each other to form one roller,
The outer peripheral surface of the cylinder itself may be breathable and water permeable. An example of the liquid absorbing roller 44 having the latter structure is EX roll (trade name) manufactured by Masuda Manufacturing Co., Ltd.

The liquid absorbing roller 44 is arranged on the upper surface side of the metal thin plate 12 so that the axial direction thereof is orthogonal to the conveying direction of the metal thin plate 12, and the outer peripheral surface of the cylinder of the liquid absorbing roller 44 is the metal thin plate 12.
Touch the upper surface of the. Further, when a plurality of liquid absorbing rollers 44 are arranged, as shown in FIG. 4, the spray nozzles 16 arranged in a direction orthogonal to the conveying direction of the thin metal plate 12 are arranged.
The rows and the liquid absorbing rollers 44 are arranged alternately. Further, the liquid absorbing roller 44 is preferably supported so as to be rotated according to the movement of the metal thin plate 12 in order to prevent the upper surface of the metal thin plate 12 from being scratched. Further, as shown in FIG. 5, a backup roller 46 is arranged on the lower surface side of the metal thin plate 12 at a position facing the liquid absorbing roller 44 with the metal thin plate 12 sandwiched between the liquid absorbing roller 44 and the backup roller 46. By adjusting the pressing force between the liquid absorbing roller 44 and the metal thin plate 12
It is advisable to contact the upper surface of the with a constant pressure. Further, as shown in FIG. 6, in order to prevent the fresh etching liquid ejected from the spray nozzle 16 from directly contacting the outer peripheral surface of the liquid absorbing roller 44, the outer peripheral surface of the liquid absorbing roller 44 is surrounded. It is desirable to provide a cover 50 made of heat-resistant vinyl chloride resin or the like. In FIG. 4, 14 is a spray pipe and 52 is a support roller.

In the spray etching apparatus having the liquid absorbing roller 44 as shown in FIGS. 4 and 5, the inside of the cylinder of the liquid absorbing roller 44 is vacuum-sucked by the suction pump,
The fatigued etching liquid 20 'on the thin metal plate 12 is sucked into the inside of the cylinder through the fine pores on the outer peripheral surface of the cylinder of the liquid absorption roller 44, and is drained to be connected to both ends (or one end) of the liquid absorption roller 44. Eliminated through tube 48.

Next, experimental examples of etching using the spray etching apparatus according to the present invention and the results thereof will be described.

As the thin metal plate, a low carbon aluminum killed steel plate having a thickness of 0.3 mm is used. First, the rust preventive oil adhering to the surface of the thin metal plate is degreased with a 10% sodium hydroxide solution,
After washing with water, a photosensitive solution consisting of milk casein and ammonium dichromate is applied to both sides of the metal thin plate by dipping and pulling method, and the photosensitive solution is dried by passing through a drying oven at about 140 ° C. A photoresist film having a thickness of about 6 μm was formed on each of them.

Next, a diameter of about 1 is formed on one surface of the thin metal plate.
A negative pattern having a large number of circular images of 00 μm and a transparent glass pattern on the other surface were respectively brought into vacuum contact, and exposed for 40 seconds from a distance of 500 mm using a 5 KW mercury lamp. Next, tap water at 40 ° C is 1 kg / cm
After spraying for 40 seconds on both sides of the metal thin plate with a pressure of ² to develop, the metal thin plate is dipped in a 5% chromic anhydride solution for 30 seconds as a hardening treatment, washed with water and drained.
After that, burning was performed at about 200 ° C. for 3 minutes to form a resist film on each side of the metal thin plate.

Then, the above-mentioned thin metal plate is immersed in a 2% oxalic acid aqueous solution to skin the surface of the thin metal plate to be etched, and then 2 kg of an iron chloride aqueous solution at 50 ° C. and 45 Baume degrees is applied to both sides of the thin metal plate. Spray etching was performed by spraying at a pressure of / cm ² for 5 minutes, and this was used as a sample. In the spray etching at this time, 30 spray nozzles are arranged in the transport direction of the thin metal plate, and the spray nozzle 5 is used.
The etching solution suction hood having the structure shown in FIG. 2 is provided for each one, and the spray etching apparatus is used in which 30 spray nozzles and 6 etching solution suction hoods are passed in 5 minutes. It was

Next, as a comparative example, the same spray etching apparatus as described above was used, and etching was performed under the same experimental conditions as described above with the etching solution suction hood removed, to prepare a comparative sample.

With respect to each of the samples manufactured as described above, the dimensions W ₁ , W ₂ and D shown in FIG. 7 of 20 adjacent holes were measured. In FIG. 7, 1 is a thin metal plate, 2 is a resist film, 3 is a circular image formed on the resist film 2, and 4 is a hole formed by etching. W ₁ is the diameter of the circular image 3, W ₂ is the diameter of the hole 4, and D is the depth of the hole 4. Table 1 shows the results of obtaining the average value of each dimension W ₁ , W ₂ and D and the etching factor (EF). The etching factor is E. F. = 2D /
Was calculated by the equation (W ₂ -W _1).

[0032]

[Table 1]

From the results shown in Table 1, when the spray etching apparatus according to the present invention is used, the etching rate is faster and the etching factor is higher than when the apparatus without the etching solution suction hood is used. It can be seen that the value of is also high.

The spray etching apparatus according to the present invention has the above-mentioned structure, but the scope of the present invention is not limited by the above description and the contents of the drawings, and various modifications are possible without departing from the scope of the invention. May be included. For example,
The arrangement ratio of the spray nozzle row and the liquid absorbing means in the transport direction of the thin metal plate is preferably 1: 1 as shown in FIG. 1 and FIG. 4, but even one liquid absorbing means is arranged. If this is done, the effect of the present invention can be obtained. Further, the liquid absorbing means is not limited to the one shown in the above embodiment, and various structures can be adopted.

[0035]

Since the present invention is constructed and operates as described above, when the thin metal plate is spray-etched by using the spray etching apparatus according to the present invention, the etching solution that is fatigued from the thin metal plate is removed. It is possible to completely remove it temporarily, and since the etching solution on the thin metal plate is always kept in a state of low fatigue,
The etching rate is increased by eliminating the obstruction of etching by the fatigued liquid.

Further, since there is no difference in the residual amount of the fatigued etching solution between the edge portion and the central portion of the thin metal plate, and there is no difference in the etching rate over the entire surface of the thin metal plate, the entire etched surface of the thin metal plate is uniform. It becomes possible to perform etching.

Furthermore, since the fresh etching liquid ejected from the spray nozzle is likely to directly hit the etching surface, there is an effect that highly accurate etching with less side etching can be uniformly and efficiently performed over the entire surface of the metal thin plate. is there.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration and a flow channel configuration of an entire spray etching apparatus according to the present invention.

FIG. 2 is a perspective view showing an example of a configuration of a liquid absorbing means which is a main part of this spray etching apparatus.

FIG. 3 is a front view of essential parts showing a modified example of the apparatus shown in FIG.

FIG. 4 is a perspective view showing another configuration example of the liquid absorbing means and showing the liquid absorbing means together with the spraying means for the etching liquid.

FIG. 5 is a perspective view schematically showing a state in which the etching liquid exhausted by the liquid absorbing means shown in FIG. 4 is removed from the thin metal plate.

6 is a front view of the main parts showing a modified example of the apparatus shown in FIG.

FIG. 7 is a vertical cross-sectional view showing an enlarged part of the thin metal plate after etching.

[Explanation of symbols]

 10 Etching chamber 12 Metal thin plate 14 Spray tube 16 Spray nozzle 18 Etching liquid absorption hood 20 Etching liquid 20 'Fatigue etching liquid 36 Liquid suction port 44 Liquid absorption roller 48 Drain pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koichi Omoto Inventor Koichi Omoto, 480-1 Takamiya-cho, Hikone City, Shiga Dai Nippon Screen Mfg. Co., Ltd. Hikone District Office (72) Inventor Hiroji Sawada Takamiya-cho, Hikone City, Shiga Prefecture 1 at 480 Dainippon Screen Mfg. Co., Ltd. Hikone District Office

Claims (3)

[Claims] 1. A spray etching apparatus comprising a spraying means for spraying an etching solution onto the surface of a thin metal plate, wherein the exhausted etching solution ejected from the spraying means and remaining on the thin metal plate is sucked and removed from the thin metal plate. A spray etching apparatus, characterized in that it is provided with a liquid absorbing means. 2. A plurality of rows of spraying means arranged in parallel in a direction orthogonal to the length direction of the thin metal plate and a plurality of liquid absorbing means installed so as to be orthogonal to the lengthwise direction of the thin metal plate are provided respectively, The spray etching apparatus according to claim 1, wherein the rows and the liquid absorbing means are alternately arranged in the length direction of the thin metal plate. 3. The liquid absorbing means is a liquid absorbing roller having a cylindrical shape whose both end surfaces are closed, and sucking the etching liquid into the inside of the cylinder through fine pores on the outer peripheral surface of the cylinder. The spray etching apparatus according to claim 1 or 2, wherein the axial direction is orthogonal to the length direction of the metal thin plate, and the outer peripheral surface of the cylinder is in contact with or close to the surface of the metal thin plate.