JPH0499152A - Fe-ni alloy excellent in etching characteristic - Google Patents

Abstract

PURPOSE:To produce an Fe-Ni alloy sheet having high-precision etching characteristic by applying surface treatment to a sheet of an Fe-Ni alloy having a specific composition and remarkably reducing C and other impurities in the extreme surface layer. CONSTITUTION:As a shadow mask material and a lead frame material requiring high-precision etching characteristic, an Fe-Ni alloy having a composition consisting of, by weight, 30-80% Ni (or 25-40% Ni and 5-20% Co), <0.25% Si, <0.5% Mn, and the balance Fe is worked into a sheet, e.g. of 0.25mm thickness. Subsequently, this sheet is heated in a hydrogen atmosphere or cleaned with surfactant and organic solvent, by which the concentrations of C and 0 at a depth of 10Angstrom from the surface are reduced to <=20 atomic %, respectively, and also the total amount of impurities, such as S, Ci, P, and B, other than C and 0 is regulated to <=5 atomic %. By this method, the Fe-Ni alloy sheet excellent in high-precision etching characteristic can be obtained.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an Fe-Ni alloy with excellent etching properties used in shadow mask materials and lead frame materials that require highly accurate etching, and This relates to the shadow mask and lead frame used.

[Prior Art] Fe-Ni alloys targeted by the present invention include amber alloys such as 36% Ni-Fe alloys used in shadow masks for color picture tubes, and 42% Ni alloys used in IC lead frames. -Fe alloy, 50% Ni-Fe alloy, 29% Ni-17% Go-Fe alloy, etc.

In recent years, color picture tubes have become increasingly high in n-thinness, and a shadow mask with a small pitch of perforations formed by etching of the shadow mask has become necessary.

Further, as the number of integrated circuit elements increases, IC lead frames have become extremely complex and have a large number of bins. Recently, the etching process, which used to be mainly used for the 64-pin class, has been applied to 160 to 240 pins, and even ultra-high number of pins with 240 pins or more.

Fe--Ni alloys used in such applications are particularly required to have highly accurate etching properties.

Etching properties of Fe-Ni alloys have long been attracting attention as an important technical issue; for example, in JP-A-61-82
No. 453 discloses that the carbon content can be controlled to 0.01% or less, and JP-A-61-84356 discloses that etching properties can be improved by further controlling nonmetallic inclusions. There is.

Moreover, in Japanese Patent Application Laid-open No. 63-128120, Fe-N
By preventing the formation of a nitride layer on the surface of the thin plate by performing strain relief annealing during the manufacturing process of the metal alloy thin plate for i-based alloy shadow mask in an atmosphere containing 95% or more hydrogen, or by preventing the formation of a nitride layer on the thin plate surface, Publication No. 128185 describes that etching properties can be improved by removing an oxide layer or a nitride layer formed on the surface of a thin plate during annealing by pickling or the like.

However, in the etching process of high-definition shadow masks and extremely high-bin lead frames of the 240-bin class, there is currently a demand for alloys with even better etching properties.

[Problem to be solved by the invention] For example, in an ultra-high definition shadow mask, even if a dimensional error of about 1 μm occurs in the hole portion formed by etching, it will be visually confirmed as unevenness and will be defective. .

In addition, in ultra-multi-bin lead frames, dimensional accuracy cannot be obtained due to poor etching properties, resulting in problems such as inner leads coming into contact with each other.

The object of the present invention is to improve the etching properties of Fe-
An object of the present invention is to provide a Ni-based alloy and a shadow mask and lead frame using the same.

[Means for Solving the Problems] The present inventor conducted a detailed study on the alloy composition distribution of Fe-Ni alloys in cross sections and longitudinal sections, and found that Fe-Ni alloys used in lead frames and shadow masks. It was found that impurities were concentrated in the surface layer of the thin plate, and the surface was contaminated.

If such impurities exist in the surface layer of the alloy, the corrosion resistance of the alloy to etching will change, reducing the initial etching rate and also worsening the adhesion between the alloy and the resist. Etching liquid can easily penetrate, and etching progresses in the lateral direction.
It has been found that the so-called side etching becomes large and the processing accuracy in etching deteriorates.

Furthermore, we investigated etching properties and contamination on the surface of this alloy, and found that extremely good etching properties can be achieved by lowering the concentration of carbon concentrated particularly in the surface layer.

That is, the alloy of the present invention contains 30 to 60% by weight of Ni, S
It is characterized by comprising 0.25% by weight or less of i, 0.5% by weight or less of Mn, and the remainder Fe and impurities, and the concentration of carbon, which is an impurity, at a depth of 1OA from the surface to be etched is 20 atomic% or less. Fe-Ni alloy with excellent etching properties, or Ni 25-40% by weight, 005-20% by weight
, 5iO025 Juya% or less, Mn 0.5% by weight or less,
The remainder consists of Fe and impurities, and the concentration of impurity carbon at the depth of IOA from the etched surface is 2.
It is a Fe--Ni alloy with excellent etching properties characterized by a content of 0 atomic % or less.

Here, the concentration of an element at a depth of 10 layers can be determined by removing only 10 layers from the surface by sputtering and analyzing it by X-ray photoelectron spectroscopy (ESCA).

Furthermore, lowering the concentration of carbon in the extreme surface layer and lowering the overall concentration of other impurities such as oxygen, S, CQ, P, and B are also effective in improving etching properties.

Therefore, the alloy of the present invention further contains oxygen and carbon.

The overall concentration of impurities other than oxygen is desirably 20jJX% or less and 5 atoms or less, respectively, from the surface to the IOA concentration.

[Function] In the present invention, the carbon concentration of IOA is reduced by 20i from the surface.
The reason why it is specified to be less than 20% is because if the concentration of carbon from the surface exceeds 20%, the etching property will be significantly deteriorated.

In fact, the state of carbon contamination on the surface was determined by ESCA on the outermost surface (
In other words, analysis with a depth of less than 10 people cannot provide accurate evaluation. However, by sputtering the surface
When an analysis is performed on a surface from which humans have been removed, there is a clear correlation between its carbon concentration and etching properties.

Furthermore, by further proceeding with surface removal by sputtering,
Measurements taken at the surface with about 30 people inside showed that the composition was almost the same as that of the entire alloy, and it was estimated that the contamination range was at most about 30 people from the surface. In other words, contamination by impurities starts at the outermost surface depth of about 3 people and continues up to about 25 people, but since the carbon concentration at a depth of 10A is most correlated with etching performance, the present invention Define the impurity concentration at depth.

It is thought that such concentration of carbon on the surface mainly originates from oils attached during the Fe--Ni alloy manufacturing process or during packaging. It is also believed that oxygen was oxidized or adsorbed from the atmosphere.

The method for removing these impurities from the alloy surface is as follows:
Method 1 of heating in hydrogen, method of carefully cleaning with a surfactant and organic detergent, etc. can be used.

In addition, when heating in hydrogen, the dew point should be set at 0°C to +l.
Preferably it is carried out at 0°C and 700°C to 800°C.

It is practically difficult to keep the dew point below -30°C, and when it exceeds +10°C, the amount of oxidation on the alloy surface increases, which is not preferable. Increasing the dew point increases the amount of impurities removed, but also increases the amount of oxidation on the alloy surface, so it is desirable to adjust the dew point of the atmosphere depending on the material application.

[Example code] Examples of the present invention will be described in detail below.

0.25 mn each for alloys with compositions shown in Table 1
) was created.

These products were heat-treated in a hydrogen atmosphere with a dew point of -30°C for 2 minutes at a temperature ranging from 725°C to 800°C.

The element distribution in the extreme surface layer of the obtained alloy strip was measured by ESCA while the surface was removed by sputtering.

Figure 1 shows the case of 42% Ni-Fe alloy, with 2
The carbon concentration distribution in the depth direction from the surface of the alloy is shown for the alloy that was heat-treated for 1 minute and the alloy that was not heat-treated as a comparative example.

It can be seen from FIG. 1 that this atmospheric heat treatment can significantly reduce the carbon concentration in the surface layer.

Table 2 shows the impurity element concentrations measured by 10 people from the surface of the alloys shown in Table 1.

In addition, in order to evaluate the etching properties, the results of measuring the etching speed and etching on the surface were also shown in the second table.
Shown in the table.

Regarding the etching speed, a round hole shape of 1 m + nφ was etched from both sides using FeC1, FB solution with a specific gravity of 1.38 heated to 40°C as the etching liquid.
Evaluation was made by measuring the time required for penetration.

Note that etching on the surface refers to the second ffl(a)
As shown in FIG. 2, it has an etched portion 1. At this time, the cross section is as shown in FIG. 2(b). In the evaluation of etching damage during etching, those with etching as shown in Fig. 2 were judged as poor, and those with no visible etching were evaluated as good.

Table 2 shows that by heat-treating Fe-Ni alloys in a hydrogen atmosphere, it is possible to reduce the impurity concentration at a depth of 10 cm from the surface to be etched, and by reducing the carbon concentration to 20% or less, the etching properties can be extremely improved. It turns out that it can be made into something excellent.

(Example) A strip having the alloy composition shown in Table 1 obtained in the same manner as in Example 1 was subjected to the cleaning process described below, and the impurity element concentration at 108 from the surface and etching property were measured.Results are shown in Table 3.

The washing process is as follows.

(1) Soaking in neutral detergent (surfactant) for 10 minutes (2) Washing with water (ion-exchanged water) for 1 minute (3) Trichlorethylene steam cleaning for 1 minute (4) Soaking in trichlorethylene
1 minute (5) Acetone washing (6) Drying From Table 3, it can be seen that, as in Example 1, the carbon concentration from the surface can be reduced to 20 at % or less, and excellent etching properties can be obtained. .

Such an alloy is extremely effective when applied as a lead frame material for etching multiple bottles with high precision or as a precision shadow mask material.

[Effects of the Invention] According to the alloy of the present invention, defects such as etching damage do not occur during etching, and highly accurate etching is possible. Ideal as a super multi-bin lead frame material.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the carbon concentration distribution of the present invention, Figure 2 (a
) and (b) are explanatory views of etching damage. l: Etched area

Claims (4)

[Claims] (1) Consisting of 30 to 60% by weight of Ni, 0.25% by weight or less of Si, 0.5% by weight or less of Mn, and the balance Fe and impurities, and the concentration of carbon as an impurity at a depth of 10 Å from the etched surface is 20 atomic%. An Fe-Ni alloy with excellent etching properties, characterized by: (2) Ni25-40%, Co5-20%, Si0.2
5% by weight or less, Mn 0.5% or less, the balance being Fe and impurities, and the concentration of carbon as an impurity at a depth of 10 Å from the etched surface is 20 atomic% or less. Excellent etching properties. Fe-Ni alloy. (3) The Fe-Ni alloy with excellent etching properties according to claim 1 or 2, wherein the concentration of oxygen as an impurity at a depth of 10 Å from the surface to be etched is 20 atomic % or less. (4) Fe-Ni system with excellent etching properties according to claims 1 to 3, characterized in that the total amount of impurities other than carbon and oxygen at a depth of 10 Å from the surface to be etched is 5 at % or less alloy.