KR19980032326A - Pre-etching method of metal thin plate - Google Patents

Abstract

In the present invention, when pre-etching a metal thin plate made of a nickel-containing material such as an invar material using a pre-etching liquid containing oxalic acid, precipitation of nickel hydroxide on the main surface of the metal thin plate is suppressed, The present invention provides a method of eliminating the rise of the resist film due to the deposition of nickel and preventing the etching failure. As a solution, the liquid temperature of the preetching liquid 18 in which the metal thin plate 10 is immersed is set to a temperature range of 10 ° C to 25 ° C.

Description

Pre-etching method of metal thin plate

1 is a schematic diagram showing an example of the configuration of a preetching apparatus used to implement a preetching method according to the present invention;

2 is a cross-sectional view showing a cross-sectional photograph of a surface portion of a metal sheet when the metal sheet is preetched to be made of an invar material by a conventional polishing method

FIG. 3 is a cross-sectional view illustrating a cross-sectional photograph in which part of FIG. 2 is enlarged;

4 is a cross-sectional view showing an enlarged cross-sectional photograph of an angle different from that of FIG.

* Description of the symbols for the main parts of the drawings *

10 metal foil 11: pre-etching device

18: preetching liquid 20: preetching bath

22: sponge roller 24: water supply pipe

The present invention, for example, in the case of producing an etching product such as a shadow mask for color water pipes, an aperture grill for Torinitron (registered trademark), a lead frame for semiconductor devices, etc. using a photo etching method, Prior to the present invention, a metal thin plate on which a resist film having a predetermined pattern is formed on a main surface thereof, in particular a material containing nickel, for example, an Invar material which is an iron-nickel alloy containing 36% nickel. The present invention relates to a preetching method for removing an oxide film or a resist residual film adhered to an etching target surface of a metal thin plate from an etching target surface.

Etching products, such as a shadow mask for a water tube, an aperture grill, and a lead frame for semiconductor elements, are manufactured by processing strip | belt-shaped metal thin plates, such as a low carbon aluminide steel, using the photoetching method. In a series of manufacturing processes of this etching product, in an etching process, as disclosed in Unexamined-Japanese-Patent No. 58-212033 etc., preetching of a metal foil is performed before spray etching. This pre-etching is used to remove an oxide film adhered to the etching etching surface of the metal foil or a resist residual film which remains extremely thin as if the coating surface is etched after developing and hard-film treatment. It is done for the purpose. In the pre-etching method, the strip-shaped metal thin plate is conveyed in the longitudinal direction, and the metal thin plate is immersed in a pre-etching liquid which is a thin lean solution having an acid concentration. The pre-etching liquid contains sulfuric acid and hydroxyl, which are a cleaning agent, and hydrogen peroxide, which is a decomposition agent of casein in the resist film, and a pre-etching liquid having a liquid temperature of about 30 ° C. is conventionally used to increase the pre-etching efficiency.

By the way, in recent years, the color receiving tube tends to be enlarged, and accordingly, a thermal deformation called a doming phenomenon (a large number of electron beams radiated from the electron gun in the color receiving tube and directed toward the phosphor is used as a shadow mask or aperture grill as an electron beam in an unnecessary direction). Collision and absorption cause the temperature of the shadow mask or aperture grill to rise, and there is a problem that color shift occurs on the display screen of the color receiving tube due to the large influence of thermal deformation caused by local thermal expansion. . In order to solve this problem, an invar material having a low thermal expansion coefficient, which is an iron-nickel alloy containing 36% nickel, has been used instead of the aluminum guild steel which has been conventionally used as a shadow mask or aperture grill material in recent years.

However, when preetching the metal thin plate made of invar material by the same method as the conventional method, the following new problems which did not occur in the preetching process of the metal thin plate made of low carbon aluminide steel have occurred. .

The low carbon aluminide steel has almost 100% iron, and iron (Fe (COO) ₂ ) is produced by the reaction between the iron component of the aluminium steel and hydroxyl in the pre-etching liquid. Due to its relatively high solubility in water (22 mg / 100 g-cold water), most of it is dissolved in the pre-etching liquid. On the other hand, the component of the Invar material is 64% of iron, 36% of nickel, and nickel hydroxide (Ni (COO) ₂ ) is produced in addition to the above-mentioned iron hydroxide by reaction with the hydroxide in the preetching liquid. Since nickel hydroxide is poorly soluble (0.3 mg / 100 g-cold water), unlike iron hydroxide, it precipitates on the surface of a metal thin plate.

FIG. 2 is a diagram showing a cross-sectional photograph of the surface portion of the metal sheet when the metal sheet made of an invar material is preetched. FIG. 3 is a diagram showing a cross-sectional photograph enlarged in part thereof, and FIG. The enlarged cross-sectional photograph of the angle different from 3 degree | times is drawn. In this test, a factory-type apparatus was formed by forming a patterned resist film on the surface of a metal thin plate (manufactured by Nippon Steel Industry Co., Ltd.) having a thickness of 0.1 mm by a conventional method. 1 minute pre-etching (The composition of the pre-etching liquid was industrial water: 400 ml (97.80 wt%), 98% sulfuric acid: 160 ml (0.06 wt%), fishery: 8 kg (1.93 wt%), 35% hydrogen peroxide Number: 6 kg (0.51% by weight), the temperature of the preetching liquid was 30 DEG C), the sample was molded with resin, the mold malle was polished to form a cross section, and then the cross section was focused on an ion beam scanning device. (Jewel) (JEOL JIBL-100) was used for scanning. In FIGS. 2-4, it is a crack which generate | occur | produced by shrinkage of a monovalent metal thin plate, a bivalent resist film, a trivalent mold resin, and a tetravalent resin, and is pentavalent nickel hydroxide.

As can be seen from FIG. 2 to FIG. 4, the etching target surface of the metal thin plate 1 is etched by about 2 to 3 µm by the preetching process, and the nickel hydroxide 5 is etched on the etching target surface. Has precipitated. In addition, the lower part of the edge part of the resist film 2 is also slightly etched, and nickel hydroxide 5 precipitates in the part. And the edge part of the resist film 2 is pushed up from the bottom by the convexly raised part of the nickel hydroxide 5, and since the Invar material is inferior to adhesiveness with the resist film 2 compared with an aluminum guild steel, As shown in FIG. 3 and FIG. 4, the edge part of the resist film 2 has risen, and the space | interval 6 arises between the lower part of the resist film 2 and the surface of the metal thin plate 1. FIG. . As a result, in the etching step after the preetching, the etching liquid also penetrates into the portion of the gap 6 and is etched to the surface of the metal thin plate 1 which should not be etched in the first place, and becomes a shadow mask or an electron beam passing part of the aperture grill. The etching defect that a hole does not shape | mold to a desired shape will generate | occur | produce.

The present invention has been made in view of the above circumstances, and in the case of preetching a metal thin plate made of a nickel-containing material, such as an invar material, using a preetching liquid containing oxalic acid, the main surface of the metal thin plate It is an object of the present invention to provide a pre-etching method that can control the precipitation of nickel hydroxide in the main body, eliminate the rise of the resist film due to the precipitation of the nickel hydroxide, and at the same time prevent the etching failure.

This invention is a means for solving the subject, The invention concerning Claim 1 makes the temperature of the preetching liquid which is a lean solution whose acid concentration containing a hydroxyl acid dilute, into the temperature range from 10 degreeC to 25 degreeC, It is characterized by immersing the metal thin plate in the pre-etching liquid of the liquid temperature to pre-etch.

The invention according to claim 2, wherein, in the preetching method according to claim 1, the cleaning liquid is supplied to the main surface of the metal sheet after being immersed in the preetching liquid to remove nickel hydroxide adhering to the main surface of the metal sheet. do.

In the preetching method of the invention according to claim 1, since the liquid temperature of the preetching liquid is 25 ° C or less,

Ni → Ni ₂ + 2e _-

Ni + (COO) _22- → Ni (COO) ₂

The progress of reaction is suppressed, and the precipitation of nickel hydroxide on the main surface of the metal thin plate is suppressed. For this reason, floating of the resist film which arises by precipitation of nickel hydroxide is prevented, and an etching defect does not arise.

On the other hand, since the liquid temperature of the pre-etching liquid is 10 ° C. or more, the pre-etched liquid is sufficiently preetched on the main surface of the metal thin plate, and the oxide film and the resist residual film adhered to the etched surface of the metal thin plate are completely removed from the etched surface.

In the preetching method of the invention according to claim 2, a small amount of nickel hydroxide is deposited on the main surface of the metal thin plate during the preetching process, and nickel hydroxide is attached to the main surface of the metal thin plate drawn up from the preetching liquid. Since the cleaning liquid is supplied to the main surface of the metal thin plate, the nickel hydroxide is washed off from the main surface of the metal thin plate before the etching process, and the metal thin plate is completely etched away with the nickel hydroxide adhering to the main surface of the metal thin plate.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of this invention is described with reference to FIG.

1 is a schematic view showing an example of the configuration of a preetching apparatus used to implement the preetching method according to the present invention. In the previous step, the metal strip 10 having a resist pattern having a predetermined pattern formed on the main surface after completion of development and dura maturing, for example, a long strip-shaped metal sheet 10 having a thickness of about 0.1 mm to 0.3 mm made of an invar material, is, for example, It is continuously conveyed at about 0.5 m / min-3 m / min, and is conveyed to the preetching apparatus 11. As shown in FIG. And the metal thin plate 10 is guided by the conveying rollers 12, 14, and 16 into the preetching bath 20 in which the preetching liquid 18 was accommodated, and it is sent out from the preetching bath 20, and is shown in figure. It is conveyed to the etching chamber which is not.

As the pre-etching liquid 18, a composition having the same composition as that used conventionally may be used. When an example of the composition is given, 2% by weight of hydroxyl, 35% hydrogen peroxide 1.5% by weight, 98% sulfuric acid, 0.07% by weight, and industrial water 96.5 It is an aqueous solution which consists of weight%. And the temperature of a preetching liquid is adjusted to the temperature range from 10 degreeC to 25 degreeC, Preferably it is the temperature range from 18 degreeC to 22 degreeC.

Moreover, a pair of sponge rollers 22 are arrange | positioned just in front of the conveyance direction of the conveyance roller 16 in the pre-etching bathtub 20, and each sponge roller 22 is driven by the conveyance of the metal thin plate 10. As shown in FIG. Each of them is rotatably supported so as to rotate and contact the main surface of the metal thin plate 10. Above each of the sponge rollers 22, water supply pipes 24 for dropping the washing water toward the main surface of the sponge rollers 22 are respectively provided, and from each of these water supply pipes 24, each sponge roller ( Each of the washing water is supplied to 22, and the washing water is uniformly supplied to the entire surface of both main surfaces of the metal thin plate 10 through the sponge rollers 22, respectively. Moreover, below the sponge roller 22, the container 26 for receiving the liquid falling from the sponge roller 22 is provided.

When preetching the metal thin plate 10 using such a preetching apparatus 11, since the liquid temperature of the preetching liquid 18 is lower than before, it precipitates on the main surface of the metal thin plate 10 during the preetching process. Precipitation amount of nickel hydroxide is suppressed low compared with the past. In addition, even if a small amount of nickel hydroxide precipitates and adheres to the main surface of the metal thin plate 10 during the preetching process, the preetching liquid is replaced with the washing water through the sponge roller 22, so that the nickel hydroxide adhered to both main surfaces. It is washed by this washing water. And the metal thin plate 10 is conveyed from a preetching apparatus to the next etching chamber in the state in which nickel hydroxide is not affixed on the main surface at all.

According to the pre-etching method of the invention according to the above-described claim 1, the metal thin plate made of a nickel-containing material, such as an invar material, may be subjected to pre-etching treatment using a pre-etching liquid containing oxalic acid. Since precipitation of nickel hydroxide on the main surface is suppressed, floating of the resist film due to precipitation of nickel hydroxide, which has occurred conventionally, does not occur, and defective etching is prevented.

In the pre-etching method of the invention according to claim 2, even when nickel hydroxide is deposited on the main surface of the metal thin plate that is precipitated from the pre-etching liquid by depositing a small amount of nickel hydroxide on the main surface of the metal thin plate during the pre-etching process. Since nickel hydroxide is washed away from the main surface of the metal thin plate, the etching failure caused by the nickel hydroxide adhering to the main surface of the metal thin plate is prevented.

Claims (2)

A metal thin plate made of a nickel-containing material and formed with a resist film having a predetermined pattern on its main surface is immersed in a pre-etching solution, which is a lean solution of an acid containing oxalic acid. In the pre-etching method of a thin metal sheet by removing the oxide film and the resist residual film adhered to the etched surface of the metal foil from the etched surface, A pre-etching method of a thin metal plate, characterized in that the liquid temperature of the pre-etching liquid to a temperature range from 10 ℃ to 25 ℃. The method of claim 1, A pre-etching method of a metal thin plate, characterized in that the cleaning liquid is supplied to the main surface of the metal thin plate after being immersed in the pre-etching liquid to remove nickel hydroxide adhering to the main surface of the metal thin plate.