JP2952012B2 - Fe-Ni alloy with excellent etching properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an Fe-Ni-based alloy excellent in etching properties used for a shadow mask material and a lead frame material which require high-precision etching, and to use the Fe-Ni alloy. Shadow mask and lead frame.

[Prior Art] Fe-Ni based alloys to which the present invention is applied are amber alloys represented by 36% Ni-Fe alloys used for shadow masks for color picture tubes, and 42% alloys used for IC lead frames.
It means Ni-Fe alloy, 50% Ni-Fe alloy, 29% Ni-27% Co-Fe alloy and the like.

In recent years, in a color picture tube, the definition has been advanced, and a shadow mask having a small pitch of perforations by the etching of the shadow mask has been required.

Further, the IC lead frame has become extremely multi-pin and has become complicated with the high integration of integrated circuit elements. In recent years, the etching process, which has conventionally been mainly of the 64-pin class, has been adopted to the 160-240-pin type, and even the ultra-high-pin-count type of the 240-pin or more class.

The Fe-Ni-based alloy used for such an application is required to have particularly high etching performance.

The etching property of Fe-Ni alloys has been attracting attention as an important technical problem. For example, Japanese Patent Application Laid-Open No. 61-82453 discloses that the carbon content is regulated to 0.01% or less. Japanese Patent Application Laid-Open No. 61-84356 discloses that the etching property can be improved by regulating nonmetallic inclusions.

Japanese Patent Application Laid-Open No. 63-128120 discloses that a strain relief annealing performed during a manufacturing process of a metal alloy thin plate for a Fe-Ni alloy shadow mask is performed in an atmosphere of 95% or more of hydrogen so that a nitride layer is formed on the surface of the thin plate. It is described in Japanese Patent Application Laid-Open No. 63-128185 that the etching property can be improved by preventing the formation of an oxide layer or a nitride layer formed on the thin plate surface during annealing by pickling or the like. Have been.

However, in the etching of a high-definition shadow mask and a 240-pin class super-multi-pin lead frame, an alloy having even better etching properties is currently required.

[Problems to be Solved by the Invention] For example, in the case of an ultra-high-definition shadow mask, even if a dimensional error of about 1 μm occurs in a hole portion formed by etching, it is visually observed to be uneven and confirmed to be defective. .

In addition, in the case of a super-multi-pin lead frame, dimensional accuracy cannot be obtained due to poor etching properties, and problems such as contact between inner leads occur.

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

[Means for Solving the Problems] The present inventor has studied in detail the alloy composition distribution of the Fe-Ni alloy in a cross section and a longitudinal section, and found that the Fe-Ni alloy sheet used for the lead frame and the shadow mask is It was found that impurities were concentrated on the surface layer and the surface was contaminated.

If such impurities are present in the surface layer of the alloy, the corrosion resistance of the alloy against etching changes, lowering the initial etching rate and deteriorating the adhesion between the alloy and the resist. It has been found that the penetration of the etching solution becomes easy, the progress of the etching in the lateral direction, that is, the so-called side etching becomes large, and the processing accuracy in the etching is deteriorated.

Furthermore, when the etching property and the contamination of the surface of the alloy were examined, it was found that the etching property can be made extremely good by reducing the concentration of carbon concentrated particularly in the surface layer.

That is, the alloy of the present invention contains 30-60% by weight of Ni,
% By weight, Mn 0.5% by weight or less, balance Fe and impurities, and the concentration of carbon as an impurity at a depth of 10 mm from the surface to be etched is 20 atom% or less. Fe-Ni alloy or Ni 25-40% by weight, Co 5-20% by weight, Si 0.25
% By weight, Mn 0.5% by weight or less, balance Fe and impurities, and the concentration of carbon as an impurity at a depth of 10 mm from the surface to be etched is 20 atom% or less. It is an Fe-Ni alloy.

Here, the concentration of the element having a depth of 10 ° can be determined by removing the surface by 10 ° by sputtering and analyzing the surface by X-ray photoelectron spectroscopy (ESCA).

Also, lowering the concentration of carbon in the extreme surface layer and lowering the concentration of oxygen or other impurities such as S, Cl, P, and B are effective in improving the etching property.

Therefore, the alloy of the present invention further has a total concentration of oxygen and impurities other than carbon and oxygen of 10% from the surface, respectively.
It is desirably 20 atomic% or less and 5 atomic% or less.

[Action] In the present invention, the concentration of 10% of carbon from the surface is specified as 20 atomic% or less because the concentration of 10% of carbon from the surface is 20 atomic% or less.
When the content exceeds atomic%, the etching property is significantly deteriorated.

In fact, surface carbon contamination cannot be accurately assessed by ESCA analysis of the outermost surface (ie, a depth of less than 10 mm). However, when analysis is performed on a surface whose surface has been removed by 10 ° by sputtering, the carbon concentration clearly correlates with the etching property.

In addition, the surface removal by sputtering was further advanced, and measurement on a surface approximately 30 mm from the outermost surface showed almost no change from the composition of the entire alloy, and it was estimated that the range of contamination was at most about 30 mm from the surface. . That is, the contamination of the impurities starts from the outermost surface of about 3 mm and continues to about 25 mm. However, the carbon concentration at the depth of 10 mm is most correlated with the etching property. Is specified.

It is considered that such concentration of carbon on the surface is mainly caused by oils attached during the manufacturing process of the Fe—Ni alloy or during packing. Further, it is considered that oxygen was oxidized or adsorbed from the atmosphere.

As a method of removing these impurities from the alloy surface, a method of heating in hydrogen, a method of thoroughly cleaning with a surface active agent and an organic solvent, and the like can be used.

When heating in hydrogen, the dew point should be between -30 ° C and + 10 ° C.
It is preferably carried out at 700 ° C to 800 ° C.

It is practically difficult to make the dew point less than −30 ° C., and if it exceeds + 10 ° C., the amount of oxidation on the alloy surface becomes large, which is not preferable. Increasing the dew point increases the amount of removal of impurities, but also increases the amount of oxidation of the alloy surface. Therefore, it is desirable to adjust the dew point of the atmosphere according to the material application.

[Example] Hereinafter, an example of the present invention will be described in detail.

Strips of 0.25 mm were prepared for each of the alloys having the compositions shown in Table 1.

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

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

FIG. 1 shows the carbon concentration distribution in the depth direction from the alloy surface in the case of a 42% Ni-Fe alloy, which was heat-treated at 760 ° C. for 2 minutes, and as a comparative example, in which no heat treatment was performed.

From FIG. 1, it can be seen that this atmosphere heating treatment can significantly reduce the carbon concentration in the surface layer.

For the alloys shown in Table 1 in Table 2, 10 mm from the surface
Shows the concentration of the impurity element.

Table 2 also shows the results of measurements of the etching rate and the etching erosion on the surface in order to evaluate the etching properties.

As for the etching rate, an FeCl ₃ solution having a specific gravity of 1.38 heated to 40 ° C. was used as an etching solution, and the etching rate was 1 mmφ.
Was evaluated by etching the round hole shape from both sides and measuring the time required to penetrate the hole.

In addition, the etching erosion of the surface means having an etching eroded portion 1 as shown in FIG. 2 (a). At this time, the cross section is as shown in FIG. 2 (b). In the evaluation of the etching erosion in the etching, those having the erosion as shown in FIG. 2 were evaluated as poor, and those in which the erosion was not confirmed were evaluated as good.

According to Table 2, it is possible to reduce the impurity concentration at a depth of 10 mm from the surface to be etched by heat-treating the Fe-Ni-based alloy in a hydrogen atmosphere. It can be seen that it is possible to be.

(Example 2) A strip having the alloy composition shown in Table 1 obtained in the same manner as in Example 1 was subjected to a cleaning step described below, and the impurity element concentration at 10 ° from the surface and the etching property were measured. The results are shown in Table 3.

The washing process is as follows.

(1) Neutral washing (surfactant) immersion 10 minutes (2) Water washing (ion exchange water) 1 minute (3) Trichlorethylene vapor washing 1 minute (4) Trichlorethylene immersion 1 minute (5) Acetone washing (6) Drying Table 3 shows that, as in Example 1, the carbon concentration at 10 ° from the surface can be reduced to 20 atomic% 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 pins with high precision or as a high precision shadow mask material.

[Effects of the Invention] According to the alloy of the present invention, high-precision etching is possible without causing defects such as etching erosion in etching, so that a high-definition shadow mask material requiring high-precision etching and Most suitable for ultra-high pin lead frame materials.

[Brief description of the drawings]

FIG. 1 is a diagram showing a carbon concentration distribution according to the present invention, and FIGS. 2 (a) and 2 (b) are explanatory diagrams of etching erosion. 1: Etching bite

Claims (4)

(57) [Claims] (1) Ni 30-60% by weight, Si 0.25% by weight or less, Mn
Fe-Ni-based alloy excellent in etching properties, characterized in that the concentration of carbon, which is an impurity at a depth of 10 mm from the surface to be etched, is not more than 20 atom% at 0.5 wt% or less, with the balance being Fe and impurities. . 2. 25% by weight of Ni, 5-20% by weight of Co,
Excellent etchability, characterized in that the concentration of carbon as an impurity at a depth of 10 mm from the surface to be etched is 20 atomic% or less, comprising 25% by weight or less, Mn 0.5% by weight or less, balance Fe and impurities. Fe-Ni alloy. 3. The Fe-Ni-based alloy according to claim 1, wherein the concentration of oxygen as an impurity at a depth of 10 ° from the surface to be etched is 20 atomic% or less. . 4. The etching property according to claim 1, wherein the total amount of impurities other than carbon and oxygen at a depth of 10 ° from the surface to be etched is 5 atomic% or less. Fe-Ni alloy.