JPH08291351A - Iron-nickel alloy sheet and its production - Google Patents

Abstract

PURPOSE: To produce a sheet having an etching factor of high value capable of etching closely following a resist film even in the case of a resist composed of acrylic resin, concretely, a sheet of an Fe-Ni alloy having an etching factor as high as >=2.5 which is so far impossible to obtain. CONSTITUTION: This sheet is an Fe-Ni alloy sheet which contains 30-55wt.% Ni and in which etching factor, at the time when spray etching is applied by using an aqueous solution of ferric chloride (concentration, 47 deg. Baume Γ degree; temp., 60 deg.C; treating time, 6min; diameter of resist hole, 0.2mm) is regulated to >=2.5. This Fe-Ni alloy sheet can be produced by removing the surface layer of the Fe-Ni alloy sheet, containing 30-55wt.% Ni, at >=0.15C/cm<2> coulomb density by an electrolytic method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Fe-Ni alloy thin plate used as a material for a shadow mask, a lead frame, etc., and is particularly suitable for fine processing by etching.
The present invention relates to an i-based alloy thin plate and a method for manufacturing the same.

[0002]

2. Description of the Related Art Fe-Ni alloys are used as shadow masks as thin plate materials, or lead frames and wire materials for semiconductor integrated circuits due to their excellent low thermal expansion characteristics. Fe-36% Ni (Invar), Fe-42% are typical low thermal expansion Fe-Ni alloys.
Ni, Fe-50% Ni, Fe-42% Ni-6% C
r, Fe-29% Ni-17% Co (Kovar) and the like. Recently, there has been a great demand for high definition of shadow masks and multi-pins of lead frames, and these materials are required to further improve fine processing precision by etching.

As a means for improving the accuracy of etching processing, a method of reducing inclusions as much as possible has hitherto been taken.
Recently, in addition to reduction of inclusions, JP-A-3-97831
As described in No. 3, a method has been adopted in which the etching rate is increased by adjusting the texture to a collection of (200) planes or by reducing C as much as possible. Further, JP-A-63-128185 discloses that the surface of the thin plate is directly below the surface of the thin plate by a chemical means such as pickling or chemical polishing from the viewpoint of improving the resist adhesion during etching and performing highly accurate etching. It is disclosed to dissolve and remove the deteriorated layer due to the contamination caused by each treatment and processing up to that step.

Similarly, from the viewpoint of improving resist adhesion,
Japanese Unexamined Patent Publication No. 4-99152 discloses a method of decarburizing and reducing impurities C and O existing in a layer immediately below the surface (hereinafter referred to as a surface layer) by heat treatment to reduce the impurities. Japanese Patent Laid-Open No. 4-334850 discloses an example of electrolytic surface-treating treatment using oxalic acid as an electrolytic solution as a method of removing a resist film in an unnecessary portion after the developing treatment. An etching factor is often used as an index showing the etching processing accuracy. As shown in FIG. 5, the etching factor is generally the etching depth d and the side etching amount S of the portion covered with the resist.
Is defined as the ratio d / s. A large etching factor means that the side etching amount s is small, that is, an etched shape faithful to the resist pattern can be obtained.

[0005]

According to the investigation by the present inventor, the thin plate from which the surface layer has been removed by the above-mentioned pickling or chemical polishing has insufficient resist adhesion, and the etching factor is not sufficiently large, and In this method, the depth to be removed tends to fluctuate due to the degree of deterioration of the liquid when mass-produced, and it is difficult to control the removal depth. Therefore, the efficiency is low. The removal rate is also low. It was also found that the method of removing impurities in the surface layer by the above-mentioned heat treatment does not sufficiently improve the cleanliness of the surface, so that the resist adhesion is insufficient and the etching factor is not sufficiently large. In addition, since the casein-based resist that has been conventionally used contains hexavalent Cr, it is being replaced with an acrylic-based resist recently. However, the surface that has been pickled or chemically polished is
It was found that the adhesiveness was particularly poor and the etching factor was low with respect to the acrylic resist.

According to the present invention, a thin plate having an etching factor of a high value that faithfully executes the etching shape to the resist film even for a resist made of an acrylic resin,
Specifically, the first object is to provide a thin plate of an Fe-Ni alloy having a high value of 2.5 or more, which has not been obtained in the past, and the second purpose is to provide impurities on the surface of the thin plate material. It is to provide a method for obtaining a material having a high etching factor by effectively removing a surface-altered layer contaminated by the like.

[0007]

Therefore, the present inventor has studied various methods of chemically and electrochemically removing the surface-altered layer. As a result, the electrolytic method for removing the surface layer has never been obtained. In addition to being able to obtain a surface with an etching property of a factor of 2.5 or more,
It has been found that the removal amount of the surface layer can be controlled to be constant and the occurrence of insufficient removal amount can be prevented more easily than pickling or chemical polishing. That is, in the surface layer removal method using various acids, alkalis, etc., the surface layer is not dissolved in a short time, or even if the surface layer is dissolved, the reaction product generated secondarily in the liquid is not treated even after careful cleaning. It has been found that it is practically impossible to produce a material having an etching factor of 2.5 or more, because it remains on the surface of and the adhesiveness with the resist is inhibited after drying.

However, in the surface layer removal method by electrolysis,
It is inherently easy to control the removal amount of the surface by applying a predetermined current for a predetermined time, and the degree of deterioration of the liquid is small, especially because the amount of secondary reaction products formed is small. It was found that a clean surface can be easily obtained after the treatment, and a surface having an etching factor of 2.5 or more can be obtained even when a resist film containing an acrylic resin as a main component is used. The first aspect of the present invention is that the etching factor is
Although it is a thin plate of 2.5 or more, such a thin plate is, for example,
It can be sufficiently realized if the surface is prepared in a predetermined state by the method for producing a Fe-Ni alloy thin plate by removing the second electrolytic surface layer of the present invention.

That is, the first aspect of the present invention is to provide Ni 3 in weight%.
Fe-Ni alloy thin plate containing 0-55%, when spray-etched with ferric chloride aqueous solution (concentration: 47
Baume, temperature: 60 ° C., treatment time: 6 minutes, resist hole diameter: 0.2 mm), Fe-Ni alloy thin plate characterized by having an etching factor of 2.5 or more, and the second of the present invention is% by weight. Of Fe-Ni alloy thin plate containing 30 to 55% of Ni by electrolysis to remove the surface layer of the thin plate of Fe-Ni alloy at an electric energy density of 0.15 C / cm ² or more. Is the way. In the thin plate obtained by removing the surface layer by the electrolysis according to the second aspect of the present invention, a plate having a plateau-shaped portion on the surface thereof with an area ratio of 18% or less satisfies the etching factor of 2.5 or more. To do. Further, in the production method of the present invention, the electrolytic solution used is a mixed aqueous solution of sodium sulfate and sulfuric acid, the pH is 1.0 to 4.0, and the strip to be treated is continuously treated while running in its longitudinal direction. The continuous method is preferable.

[0010]

First, the Fe-Ni alloy thin plate of the present invention will be described. The Fe-Ni-based alloy containing 30 to 55% by weight of Ni, which is the object of the present invention, is the trade name of F-Ni alloy.
e-36% Ni (Invar) alloy, Fe-42% Ni alloy, Fe-50% Ni, Fe-29% Ni-6.5% C
is a general term such as o, and Fe and Ni or Co of 7
% Of the alloys mainly containing about 30% to 55% Ni
It means the whole area corresponding to%. Therefore, Fe-Ni
It is possible to add Si, Mn, Ca, etc. as deoxidizing and desulfurizing elements to the base alloys, and as a characteristic improving element such as strengthening, proof stress reduction, hot workability, etc., 3% or less, in some cases 5% or less Nb, Ti, Al, V, Cr, B, etc. are included as required.

More specifically, Fe-29% Ni-
6.5% Co or 3% or less of this Ni replaced by an equal amount of Cu, Fe-33.3% Ni-3% Cu or 0.001% B added thereto, Fe-36% N
i, or 2% Ti, 1.5% Al, 2% Cr,
2% Nb, 2% V, 0.003% B added, Fe-42% Ni, Fe-50% Ni and Fe-5
2% Ni or Ti, Al, Cr with the above levels
For example, Nb, V, and B are added.

The Fe-Ni alloy thin plate of the present invention has an etching factor of 2.5 or more even when a resist film containing an acrylic resin as a main component is used as the resist film, as shown in the following measuring method. Is to
As a result, it is possible to realize an etching shape that is more faithful to the pattern. The method of etching and the method of measuring the etching factor are as follows. First, after coating a resist solution containing an acrylic resin as a main component on the surface of a material treated by the method of the present invention, etc., a drying-exposure-developing-drying process is performed, and a large number of holes having a diameter of 0.2 mmφ are formed. The provided resist film is formed. Then, a FeCl ₃ aqueous solution (60 ° C., 47 Baume) is sprayed for 6 minutes for etching, and then the depth d of the hole and the spread s of the hole are measured by the definition of FIG. 5, and the etching factor is calculated by d / s. .

Next, the operation of the method invention of the present invention will be described. The reason why the surface from which the deteriorated layer is removed by the electrolytic method in the present invention exhibits a higher etching factor than the surface obtained by the conventional pickling method is considered to be due to the following action. That is, the surface of the Fe-Ni-based alloy whose surface layer has been removed by the above-mentioned electrolysis method has a step of partially showing a plate-like morphology in the process of this removal, as will be described later in detail. The plateau-shaped portion is an undissolved portion that remains as a result of selective dissolution, is an altered portion that contains impurities that inhibit the adhesion of the resist film and has low activity. Although the etching factor decreases when this plateau-like part is widely left on the surface, the method of the present invention surely reduces the area of this plateau-like part by increasing the electric quantity density (C / cm ² ). Can be made.

Moreover, on the new surface after the removal of the plateau portion, the products of the reaction become ions and are carried by the electric current. It stays at a high concentration in the very vicinity and cannot be sufficiently removed by washing with ordinary running water or ultrasonic washing, so that it does not adhere to and remain on the surface after drying, and it becomes a sufficiently fresh and active surface. Further, the new surface is rich in undulations, which is also considered to be a factor that enhances the adhesiveness of the resist film and shows high etching. As a result of the above, it is considered that the surface of the thin plate from which the surface layer has been removed by electrolysis has a high etching factor. To make the etching factor 2.5 or more,
18% of the total area of the terraced area (area ratio)
It is necessary to do the following.

The method of the present invention comprises a surface layer of 0.15 C / cm ²
It is to be dissolved and removed with the above electricity density, and in this example, the area ratio of the plateau-shaped portion is 70% by this condition.
The etching factor was reduced to about 0.2% or less, and the etching factor could be improved by about 0.2 to 0.4 as compared with the untreated material. The relationship between the charge density and the obtained etching factor changes depending on the depth of the contaminated layer. Therefore, with a material having a large degree of oxidation or the like, a desired etching factor cannot be obtained unless the removal depth is increased due to the large electric charge density. In the method invention of the present invention, in the case of continuous processing (processing performed while running a strip-shaped material to be processed in its longitudinal direction), the average depth of melting in the longitudinal direction can be accurately and uniformly controlled, It is desirable because it is possible to reduce the occurrence of a portion where the amount of removal is insufficient and deterioration of the liquid due to excessive removal.

Next, the manner of removing the surface layer by electrolysis according to the present invention will be described. Fe-Ni alloy thin plate is usually after final rolling,
It is traded in a strain-annealed state. According to the method of the present invention, the material at this stage or the material before final rolling is activated by removing the surface layer by electrolysis. When the material at this stage is subjected to the electrolytic surface layer removing treatment of the present invention, the surface state goes through the following stages. Melting progresses from a myriad of points on the flat surface due to rolling, resulting in point pits, where the pits deepen, the depth almost stops, and the flanks widen laterally to expand the area. The area becomes wider and the adjacent dents come into contact with each other (see FIGS. 1 and 2). In this step, the initial surface remains flat and the surroundings are lowered due to melting. ), The initial surface has almost disappeared, and the entire surface is covered with a new rugged surface (see FIG. 3). Further, when the electrolysis is further continued, the plateau-like portions are surely reduced, and it seems that the dissolution proceeds with the undulating surface.

The etching factor is low in the initial stage of and, rises sharply from the middle stage to the end stage, and exceeds 2.5 (the area ratio of the plateau-shaped portion at this time is 18% or less). And becomes almost saturated at. Next, desirable conditions for the method invention of the present invention will be described. Usually, as an electrolytic solution for descaling iron, a mixed aqueous solution of sulfuric acid, nitric acid, etc., and their sodium salts is used, and these can also be used in the present invention. However, it is advantageous to use sodium sulfate from the viewpoint of ease of wastewater treatment and cost. However, in an aqueous solution of sodium sulfate alone,
If the pH is too high at 5-6 and Fe-Ni alloy is used, the electrical dissolution of the surface layer will be reduced.
4 or less is recommended. The lower the pH is, the more the reaction is promoted, but if it is less than 1.0, the handling is rather difficult and the workability is deteriorated. Therefore, the pH is set to 1.0 or more, preferably 1.5 or more.

Next, the current density is preferably set to 5 mA / cm ² or more because a reaction occurs and the surface layer is dissolved at 5 mA / cm ² or more.
When the temperature of the electrolytic solution is 60 ° C. or higher, the solution is activated and not only the electrolysis but the function as an acid starts to work, so that the discoloration unevenness is likely to occur on the surface. Also, if the temperature is lower than 20 ° C, it becomes difficult to control the temperature in summer. Therefore, 20 to 60 ° C is a desirable range.

[0019]

【Example】

Example 1 First, sodium sulfate, sulfuric acid, and water were mixed as an electrolytic solution to prepare an aqueous solution having a pH of 3.0. In this solution, Fe-Ni alloy thin plate having the composition shown in Table 1 produced by the steps of dissolution-hot rolling-annealing-cold rolling-annealing.
(0.15mmt) and platinum electrode are immersed, liquid temperature 40 ℃, treatment time
The electrolytic surface layer removal treatment was performed using the thin plate as an anode under the condition of 30 seconds. Next, after the above treatment, each test piece was
After cleaning with running pure water of 40 ° C. and ultrasonic cleaning in pure water at 40 ° C. for 30 seconds, it was quickly dried with hot air, and the surface was observed with an electron microscope and the etching factor was measured under the above conditions. . The results are shown in Table 2. Also, Table 2
Current density of 5,10,20mA / cm ^{2 for} TP1
Scanning electron micrograph of material surface after 30 seconds treatment
(Magnification 10,000) are shown in Figures 1, 2, and 3, respectively.

[0020]

[Table 1]

[0021]

[Table 2]

From Table 2, if the area ratio of the plateau-shaped portion is set to 18% or less, an etching factor of 2.5 or more can be obtained, and the area ratio of the plateau-shaped portion surely decreases with an increase in the quantity of electricity. With TP1 and TP2 (thickness of oxide film measured by ESCA is larger than TP1), the area ratio of the plateau is 18% or less, that is, the electric energy density required to obtain an etching factor of 2.5 or more is considerably high. There is a big difference (the electricity density increases with the oxide film thickness),
0.2 with respect to the material in the process of electric charge density 0.15C / cm ²
There is an improvement in the etching factor of 0.4, which is slightly inferior to HNO ₃ which gave the best result in Example 2 described later, but it gives the following good result.
It can be seen that the obtained etching factor saturates with respect to the electricity density. Further, the surface newly appeared after dissolution and removal from FIG. 3 is rich in undulations, and the surface will be described in a comparative example described later. It can be seen that the pickling does not show the white reaction product which can be seen on the surface newly appeared.

(Example 2) As a comparative example, the etching factor was measured on the surface obtained by immersing in various acids and alkalis (cleaning, drying, resist film formation and measurement of the etching factor were performed as in Example 1). As well). The liquid used was mixed with water to have concentrations of 0.1 N and 2 N, and the two materials shown in Example 1 were immersed in this liquid (temperature: 40 ° C., time: 30 seconds). Table 3 shows the results. Further, in FIG. 11 (TP1) scanning electron micrograph of the sample surface (magnification 10,00
(0 times). It can be seen from Table 3 that the immersion in acid, alkali or the like has an etching factor of HNO ₃ of 2.4 even at the highest level, and is not sufficiently improved. In FIG. 4, white spots are reaction products generated during pickling, and the reaction products could not be removed even by using hot water and ultrasonic cleaning in hot water together. The surface of FIG. 4 is smoother than the surface of the treated article according to the present invention of FIG. It is considered that the remaining reaction products, smoothness, etc. are responsible for the small etching factor.

[0024]

[Table 3]

[0025]

As described above, the Fe--N of the present invention is used.
Since the i-based alloy thin plate has a high etching factor of about 2.5 to 3.0 even when measured using an acrylic resin-based resist, it is possible to perform fine etching processing which is required more and more in recent years. Further, the method for producing the Fe-Ni alloy thin plate of the present invention is a specific method for actually obtaining a material having a high etching factor of 2.5 or more, even when measured using an acrylic resin resist, and waste water treatment. It is also advantageous in terms of equipment. Further, both inventions are required to have higher precision. This greatly contributes to the production of lead frames and shadow masks.

[Brief description of drawings]

FIG. 1 is a scanning electron micrograph of the surface of a thin plate of the present invention obtained by subjecting the material of TP1 to an electrolytic surface layer removal treatment at an electric charge density of 0.15 C / cm ² (plateau area ratio: 56%, etching factor; 2.3).

FIG. 2 is a scanning electron micrograph of the surface of the thin plate of the present invention in which the material of TP1 was subjected to electrolytic surface layer removal treatment at an electric charge density of 0.3 C / cm ² (plateau area ratio: 9%, etching factor;
2.9).

FIG. 3 is a scanning electron micrograph of the surface of the thin plate of the present invention in which the material of TP1 is subjected to electrolytic surface layer removal treatment at an electric charge density of 0.6 C / cm ² (plateau area ratio: 6%, etching factor: 3.0). Is.

FIG. 4 is a scanning electron micrograph of the surface of a thin plate of a comparative example obtained by pickling the material of TP1 with an aqueous HNO ₃ 2N solution.
(Etching factor; 2.4).

FIG. 5 is a diagram illustrating a cross-sectional view of a material after etching processing and a method for measuring an etching factor.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication H01J 29/07 H01J 29/07 Z H01L 23/48 H01L 23/48 V

Claims (5)

[Claims] 1. Fe-containing 30-55% Ni by weight.
It is a thin plate of Ni-based alloy and has an etching factor of 2.5 or more when spray-etched with an aqueous ferric chloride solution (concentration: 47 Baume, temperature: 60 ° C, processing time: 6 minutes, resist hole diameter: 0.2 mm). An Fe-Ni alloy thin plate characterized by the above. 2. A material having a surface layer removed by an electrolysis method, the surface of which is a scanning electron micrograph (magnification: 10,00).
The Fe-Ni alloy thin plate according to claim 1, wherein the plateau-like portion (the portion higher than the surrounding and having a substantially flat top surface) where the surface-altered layer remains is 18% or less in area ratio. 3. Fe-containing 30-55% Ni by weight.
Fe-N, characterized in that the surface layer of a thin plate of a Ni-based alloy is removed by an electrolysis method at a quantity density of 0.15 C / cm ² or more.
i-type alloy sheet manufacturing method. 4. The electrolyte used has a pH of 1.0 to 20 ° C.
4. The method for producing a Fe—Ni alloy thin plate according to claim 3, which is a mixed aqueous solution of sodium sulfate and sulfuric acid of 4.0. 5. The method for producing an Fe—Ni-based alloy thin plate according to claim 3, wherein the treatment is a treatment in which a strip-shaped material to be treated is continuously processed while running in the longitudinal direction thereof.