JP2002212763A - Method for manufacturing etching parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing etching parts which is capable of controlling the surface roughness in etching to a specified value or below in etching a metallic base material consisting of an iron-nickel alloy. SOLUTION: The method for manufacturing the etching parts by etching the metallic base material consisting of the iron-nickel alloy containing 30 to 50 wt.% nickel by using a ferric chloride solution comprises etching the metallic base material in the state that the potential of the metallic base material in etching exceeds 150 mV.

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 used in a cathode ray tube of a display such as a television and a computer, and an etching part such as a lead frame.

[0002]

2. Description of the Related Art In recent years, lead frames have been miniaturized, shadow masks have been refined with high precision and definition, and screens have been enlarged. The lead frames have a high tensile strength and can be made thinner for fine processing. Since the thermal expansion coefficient is almost the same as that of a silicon chip, an Fe—Ni alloy (Ni 42% by weight) that can suppress the occurrence of a package crack is widely used. Also, instead of pure iron (aluminum-killed steel), which has been mainly used in the past, the coefficient of thermal expansion at room temperature is much lower than that of pure iron (aluminum-killed steel). Fe-Ni having low thermal expansion characteristics such as an Fe-36% by weight Ni alloy (so-called invar alloy) capable of accurately maintaining the position accuracy of the holes without depending on the temperature.
A series alloy is used.

[0003] As a method of manufacturing an etching component such as a lead frame or a shadow mask, a wet etching process is generally used. As an etchant, a ferric chloride solution is mainly used because of its workability and cost. In the lead frame, the surface roughness of the etched surface is reduced for the purpose of simplifying the removal of the mold resin from the outer leads after sealing the mold resin, and for the shadow mask in order to make the electron beam transmittance in the product uniform. It is important to form a smooth etched surface. In recent high-definition shadow masks, the dimensional accuracy requirement is about ± 1 μm in the through-hole portion, and if the etching surface roughness is 1 μm or more in Ra, the dimensional accuracy requirement alone cannot be satisfied. .

[0004]

However, the roughness of the etched surface is complicatedly changed by various factors such as the temperature of the etching solution, the specific gravity, the concentration of free hydrochloric acid, the nickel content, and the oxidation-reduction potential (ORP). It is a fact. Therefore, strict management has to be performed to individually control these factors within a predetermined narrow range. For example, as the temperature of the etchant increases, the surface roughness increases, and as the specific gravity increases, the surface roughness decreases. When the concentration of free hydrochloric acid increases, the surface roughness decreases from 0% to about 1%, and the surface roughness increases when the concentration is higher than 0%.
Furthermore, the surface roughness increases as the nickel content increases. Then, when the oxidation-reduction potential (ORP) increases,
The surface roughness increases.

Since these factors are controlled within a predetermined narrow control range, actually, even if one of the factors deviates from the control range, the etched surface roughness may not always become unacceptably rough. , The management was stricter than necessary. Then, it was difficult to control the etching accuracy and the surface roughness due to the fatigue of the etching solution, the influence of the room temperature on the temperature of the etching solution, and the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an etching component capable of controlling the surface roughness during etching to a certain value or less when etching a metal substrate made of an iron-nickel alloy. It is intended to provide a manufacturing method.

[0007]

Means for Solving the Problems In order to achieve the above object in the present invention, first, in claim 1, a metal substrate made of an iron-nickel alloy is etched with a ferric chloride solution. In the method for manufacturing an etched component, the etching is performed in a state where the potential of the metal base material during the etching process exceeds 150 mV.

According to a second aspect of the present invention, there is provided the method of manufacturing an etched part according to the first aspect, wherein the metal substrate uses an iron-nickel alloy containing 30 to 50% by weight of nickel. is there.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a factor that can control the etching surface roughness when etching a metal substrate is examined again, and it is not the characteristic value of the etching solution itself but the etching on the etching surface of the metal substrate. Attention was paid to the potential representing the state of the electrochemical reaction of the liquid.

As a result, it was found that the relationship between the potential of the etched surface of the metal base material and the etched surface roughness was not linear, and that there was a point where the surface roughness rapidly changed (inflection point). In the metal base made of the iron-nickel alloy taken up in the present invention, the potential of the metal base at the time of etching is set to 150 mV.
By controlling as described above, the etching surface roughness can be stably suppressed to a low level. In addition, three nickel
In the case of a metal substrate having a content of 0 to 50% by mass, the effect is remarkable.

[0011]

The present invention will be described in detail with reference to the following examples.
<Embodiment 1> FIG. 1 is a schematic view showing a structure of a rotary electrode device used for etching conditions for etching a metal substrate, potential of the metal substrate and surface roughness. Rotating electrode device 1
Reference numeral 00 denotes an etching bath 11, an etching solution used for etching, a rotating electrode 31 made of a metal base, a reference electrode 41, and a voltmeter 51 for measuring the potential of the metal base. An amber alloy substrate (YET36: manufactured by Hitachi Metals, Ltd.) is processed into a cylindrical shape to form a rotating electrode 31, the cylindrical portion is covered with an insulating material, and a circular portion at the tip is exposed.
It was immersed in the etching solution 21 with a surface area of 0.34 cm ² . The rotating electrode 31 was rotated at 1600 revolutions per minute and immersed in a predetermined etching solution for 5 minutes. Using a silver-silver chloride electrode in a potassium chloride aqueous solution having a concentration of 3 mol / liter as a reference electrode (reference electrode) 41, the potential of the amber material during the immersion was measured 5 minutes after the immersion. In addition, all electric potentials were displayed on the standard hydrogen electrode standard (SHE). After 5 minutes, it was removed from the etching solution, washed with pure water, and degreased with acetone. Thereafter, Ra specified by JIS was measured using a surface roughness meter.

[0012] 65 kinds of etching solutions were prepared by changing the temperature, specific gravity, free hydrochloric acid concentration, ORP, and Ni content as conditions of the etching solution, and an etching test was performed to measure the potential and the surface roughness Ra. The measurement results are shown in Table 1, Table 2, and FIG.

[0013]

[Table 1]

[0014]

[Table 2]

Tables 1 and 2 show the conditions of the etching solution, the potential and the surface roughness Ra for 65 kinds of test samples.
2 shows the results of measurement. FIG. 2 is a graph in which the potential and the surface roughness Ra of 65 types of test samples are plotted on a graph. Ra is 0.8 when the potential is 150 mV or less.
When the surface roughness is up to 1.4 μm and the potential is 150 mV or more, R
It was confirmed that a had a surface roughness of 0.2 to 0.6 μm.

<Example 2> An example in which a shadow mask is manufactured using the method for manufacturing an etched component of the present invention will be described. First, a metal base 6 made of an amber alloy substrate having a thickness of 130 μm (YET36: manufactured by Hitachi Metals, Ltd.)
A water-soluble resist (FR-17:
Fuji Pharmaceutical Co., Ltd. was applied by dip coating, and dried at 60 ° C. for 30 minutes to form a resist layer 62 (see FIG. 3A).

Next, the photoresist layer 6 of the metal base 61 is formed.
2, through a negative-type photomask on which a pattern is drawn, using a 3 kW ultra-high pressure mercury lamp to obtain an integrated light amount of 1500 m
Exposure of J / cm ² was performed. As the drawing pattern on the photomask, a circular shadow mask pattern having a diameter of 100 μm for small holes and 140 μm for large holes was used. Further, a spray of common tap water as a developing solution is sprayed at a spray pressure of 0.1 MPa for 90 seconds to remove (develop) an unexposed portion of the resist layer 62, and to form a small-hole-side photoresist pattern 62 a having a small-hole opening 63. Large hole opening 64
(See FIG. 3B).

Next, the small hole side photoresist pattern 62
a and the metal substrate 61 on which the large-hole-side photoresist pattern 62b is formed is spray-etched using a ferric chloride solution as an etchant to form a small-hole opening mask 6
5 and the large hole opening mask 66 were obtained (see FIG. 3C).
The etching was performed under several types of etching liquid conditions while changing the specific gravity, the liquid temperature, and the like. Further, the potential was measured under each condition. Table 3 shows the measurement results. For the measurement of the potential, a silver-silver chloride electrode in an aqueous solution of potassium chloride having a concentration of 3 mol / l was used as a reference electrode, and the potential was indicated by a standard hydrogen electrode standard (SHE).

[0019]

[Table 3]

Next, the small-hole-side photoresist pattern 62a and the large-hole-side photoresist pattern 62b are removed by immersion in a 20% by weight aqueous sodium hydroxide solution heated to 80 ° C. for 3 minutes. Obtained a shadow mask of about 140 μm.

With respect to the shadow mask having a potential of 150 mV or more, the surface roughness Ra of the etched surface was 0.5 or less, and the variation of the through hole dimension 67 was ± 1 μm or less.

[0022]

According to the present invention, a desired etching surface roughness can be obtained by paying attention to the electric potential when etching with a ferric chloride solution using the method for manufacturing an etching part of the present invention. Thus, it is possible to provide an etched part having excellent surface roughness and dimensional accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a rotary electrode device for measuring conditions, potential, and etching surface roughness of an etching solution.

FIG. 2 is an explanatory diagram showing the relationship between the potential and the surface roughness of a sample etched using a rotating electrode device.

FIG. 3 is an explanatory view showing a manufacturing process of manufacturing a shadow mask by etching a metal base material using the manufacturing method of the etching component of the present invention.

[Explanation of symbols]

 11 Etching bath 21 Etching solution 31 Rotating electrode 41 Reference electrode 51 Voltmeter 100 Rotating electrode device 61 Metal substrate 62 Resist layer 62a Small hole resist pattern 62b ... Large hole resist pattern 63... Small hole opening 64... Large hole opening 65... Small hole opening mask 66.

Continued on the front page (72) Inventor Eiji Nakagawa 79-5 Tokiwadai, Hodogaya-ku, Yokohama-shi, Kanagawa Prefecture Inside the Faculty of Engineering, Yokohama National University (72) Inventor Yoshikazu Miyata 79-5 Tokiwadai, Hodogaya-ku, Yokohama-shi, Kanagawa F Term (reference) 4K057 WA10 WA11 WB02 WB03 WB17 WE08 WG10 WL03 WN01 WN03 5C027 HH11 5F067 DA16 EA02

Claims (2)

[Claims] 1. A method for manufacturing an etched part, comprising etching a metal substrate made of an iron-nickel alloy with a ferric chloride solution, wherein the metal substrate is etched in a state where the potential of the metal substrate during the etching process exceeds 150 mV. A method for manufacturing an etched component. 2. The method according to claim 1, wherein the metal substrate is made of an iron-nickel alloy containing 30 to 50% by weight of nickel.