JP2001335969A - Peeling solution for peeling lead-free alloy on nickel or iron-nickel alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a peeling solution in which a lead-free tin alloy layer on a nickel or an iron-nickel alloy substrate as and a nickel (iron nickel alloy)-tin alloy under layer can be peeled so that the dissolution of the substrate is low suppressed as possible, and the surface after the peeling treatment is, and further, replating can stably be performed on to the smooth or substrate after the peeling. SOLUTION: As this peeling solution, an aqueous solution at least containing alkanesulfonic acid in the range of 35 to 420 mL/L, containing (meta) nitrobenzenesulfonic acid or the salt thereof in the range of 10 to 300 g/L and further containing one or more kinds selected from the groups consisting of thiourea, alkylthiourea and aromatic thiourea in the range of the solubility of >=5 g/L is used, and the peeling of a tin-copper alloy as a lead-free tin alloy is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stripping solution for stripping a lead-free tin alloy on nickel or iron-nickel alloy, and more particularly to a lead-free tin alloy layer provided by plating on nickel or iron-nickel alloy, The present invention relates to a stripping solution for stripping a nickel (iron nickel alloy) -tin alloy layer present thereunder.

[0002]

2. Description of the Related Art In recent years, nickel and iron-nickel alloys have been used as materials for lead frames and connectors for mounting electronic components such as transistors and ICs, or as base layers. For example, on a lead frame, a pattern made of a tin layer or a tin alloy layer such as a tin-lead alloy (solder) is formed for various purposes by electroplating or the like. In the removing step or the like, the tin layer or the tin alloy layer on the lead frame is removed. Also, when recovering nickel or an iron-nickel alloy from a discarded lead frame, it is necessary to remove the tin layer or the tin alloy layer.

When a tin layer or a tin alloy layer formed on a lead frame, a connector, or the like as described above is peeled, (1) not only the tin layer or the tin alloy layer but also the nickel (iron-nickel alloy) )-The tin alloy layer can be reliably peeled off, (2) The material made of nickel or iron-nickel alloy or the underlayer is less dissolved at the time of peeling (normally 0.1 μm / min or less), (3) The material after peeling (4) The appearance of the tin layer or tin alloy layer formed by re-plating and the appearance after heat treatment are required to be flat without discoloration or generation of smut. You.

Further, in recent years, from the viewpoint of environmental protection, tin alloys containing no lead harmful to the human body, for example, tin-copper alloys, tin-bismuth alloys, tin-silver, instead of tin-lead alloys (solders) Switching to an alloy or the like is desired.

A conventional stripping solution used for removing a tin layer or a tin alloy layer is, for example, a stripping solution containing an aqueous solution of alkanesulfonic acid and ferric nitrate as disclosed in Japanese Patent Publication No. 4-80117. A stripping solution containing a thiourea, a halogen compound, an inorganic acid and / or an organic acid as disclosed in JP-A-63-161178 is known.

[0006]

However, the stripping solution disclosed in Japanese Patent Publication No. 4-80117 is for stripping a tin layer or a tin alloy layer formed on a copper surface, and is intended to remove nickel or iron. When the tin layer or tin alloy layer formed on the nickel alloy is peeled off, the material of nickel or iron-nickel alloy or the underlayer dissolves extremely at the time of peeling, and the flatness of the surface deteriorates. In this case, there is a problem that poor adhesion and blistering occur.

A stripper disclosed in Japanese Patent Application Laid-Open No. 63-161178 is also for stripping a tin layer or a tin alloy layer formed on a copper surface, and is formed on nickel or an iron-nickel alloy. When the stripped tin layer or tin alloy layer is peeled off, the sulfur component contained in the stripping solution causes a problem that a film is formed on the surface of the nickel or iron-nickel alloy material or the underlayer, and re-plating is performed. There was a problem that blistering would occur if performed.

Further, none of the above-mentioned stripping solutions removes a lead-free tin alloy on a material made of nickel or an iron-nickel alloy. There has been a problem that the material made of nickel or an iron-nickel alloy or the underlayer at the time of peeling is extremely dissolved, the flatness of the surface is reduced, and poor re-plating after peeling causes poor adhesion or blistering.
Therefore, there is a demand for the development of a stripping solution capable of stripping a lead-free tin alloy on nickel or an iron-nickel alloy while satisfying all of the above conditions (1) to (4).

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been developed in view of the above circumstances. A lead-free tin alloy layer provided on a material or an underlying nickel or iron-nickel alloy or a nickel (iron) The nickel alloy) -tin alloy layer can be peeled off so that the dissolution of the material and the underlayer is extremely low, and the surface after the peeling becomes flat. An object of the present invention is to provide a stripping solution capable of performing plating stably.

[0010]

In order to achieve such an object, a stripping solution for stripping a lead-free tin alloy on a nickel or iron-nickel alloy according to the present invention is used for stripping a tin-copper alloy which is a lead-free tin alloy. A stripping solution containing at least alkanesulfonic acid in a range of 35 to 420 mL / L, containing (meth) nitrobenzenesulfonic acid or a salt thereof in a range of 10 to 300 g / L, and further containing thiourea; The composition was such that at least one of the group consisting of alkylthiourea and aromatic thiourea was contained in the solubility range at 5 g / L or more.

In the above, 70% methanesulfonic acid is used as the alkanesulfonic acid in an amount of 50 to 600 mL / ml.
L, sodium metanitrobenzenesulfonate in a range of 10 to 300 g / L, and thiourea in a solubility range of 5 g / L or more in a solubility range.

The stripping solution for stripping a lead-free tin alloy on a nickel or iron nickel alloy according to the present invention is a stripping solution for stripping a tin-bismuth alloy, which is a lead-free tin alloy, and contains at least 35 to 420 mL / alkanesulfonic acid. L, containing (meth) nitrobenzenesulfonic acid or a salt thereof in a range of 10 to 250 g / L, containing a halogen ion in a solubility range of 0.09 mol / L or more, and containing benzotriazole, benzotriazole, The composition was such that at least 2 g / L of imidazole, imidazole and derivatives thereof were contained within the solubility range.

In the above, 70% methanesulfonic acid is contained in the range of 50 to 600 mL / L, and sodium metanitrobenzenesulfonate is contained in the range of 10 to 250 g / L.
L in the range of 0.09 mol / L or more in the solubility range, and 2 g of benzotriazole.
/ L or more in the solubility range, and benzotriazole in the range of 2 to 50 g / L.

The stripping solution for stripping a lead-free tin alloy on a nickel or iron-nickel alloy of the present invention is a stripping solution for stripping a tin-silver alloy and a tin-copper alloy which are lead-free tin alloys, and at least alkanesulfonic acid. 35-350m
L / L, (meth) nitrobenzenesulfonic acid or a salt thereof in a range of 5 to 250 g / L, and one of the group consisting of thiourea, alkylthiourea and aromatic thiourea. At least 20 g / L in the solubility range and nitric acid of 0.68 to 40.5 m
It was configured to be contained in the range of L / L.

In the above, 70% methanesulfonic acid is contained within a range of 50 to 500 mL / L, and sodium metanitrobenzenesulfonate is contained at a concentration of 5 to 250 g / L.
, And thiourea was contained in a solubility range of 20 g / L or more, and 67.5% nitric acid was contained in a range of 1 to 60 mL / L.

[0016]

Next, an embodiment of the present invention will be described.

(First Embodiment) Of the stripping solutions for stripping a lead-free tin alloy on a nickel or iron-nickel alloy of the present invention, the stripping solution for stripping a tin-copper alloy contains at least 35 to 420 mL of alkanesulfonic acid. / Meta), containing (meth) nitrobenzenesulfonic acid or a salt thereof in a range of 10 to 300 g / L, and one of a group consisting of thiourea, alkylthiourea and aromatic thiourea. It is an aqueous solution containing the above in a solubility range of 5 g / L or more.

Here, a tin-copper alloy layer, a tin-bismuth alloy layer, and the like by electroplating on nickel or an iron-nickel alloy.
When a lead-free tin alloy layer such as a tin-silver alloy layer is formed, nickel or an iron-nickel alloy reacts with tin over time to form a nickel (iron-nickel alloy) -tin alloy layer at the interface. The stripping solution of the present invention is not only a lead-free tin alloy layer,
The underlying nickel (iron nickel alloy) -tin alloy layer is also surely peeled off. The same applies to the embodiments described below.

In the stripping solution of the present invention, if the alkanesulfonic acid content is less than 35 mL / L, the solubility of the tin-copper alloy layer is low, and the stripping speed is 1 μm / min or less, which is not practical. Becomes When the content of the alkanesulfonic acid exceeds 420 mL / L, the peeling rate of the tin-copper alloy layer becomes 1 μm / min or less, and the concentration of (meth) nitrobenzenesulfonic acid or a salt thereof becomes higher than the solubility and the metal is not dissolved. Become. In the present invention, methanesulfonic acid, ethanesulfonic acid and the like can be used as the alkanesulfonic acid. For example, if 70% methanesulfonic acid is used, the content will be in the range of 50-600 mL / L.

In the stripping solution of the present invention, the content of (meth) nitrobenzenesulfonic acid or a salt thereof is 10 g /
When it is less than L, the solubility of the tin-copper alloy layer is low, and the peeling rate becomes 1 μm / min or less, which is not practical. On the other hand, if it exceeds 300 g / L, the concentration of (meth) nitrobenzenesulfonic acid or a salt thereof becomes higher than the solubility, and the compound does not dissolve. As the above salts, sodium salts, potassium salts, ammonium salts and the like can be used.

In the stripping solution of the present invention, if the content of at least one of the group consisting of thiourea, alkylthiourea and aromatic thiourea is less than 5 g / L, discoloration occurs in nickel and iron-nickel alloy. And undesirably cause smut.

Further, the stripping solution of the present invention may contain a surfactant within a solubility range, if necessary. As the surfactant, a nonionic surfactant such as polyoxyethylene triol and polypropylene glycol, and an anionic surfactant such as potassium perfluoroalkyl sulfonate and sodium dioctyl sulfosuccinate can be used.

When the tin-copper alloy layer on nickel or iron-nickel alloy is stripped using the stripping solution of the present invention as described above, the temperature of the stripping solution (treatment bath) is not particularly limited. For example, it can be set in the range of 20 to 60 ° C.

There are no particular restrictions on the iron-nickel alloy.
42 materials used for lead frame (Fe: Ni = 5
8:42) and SUS316.
When the tin-copper alloy layer is formed by re-plating, it is preferable to form the tin-copper alloy layer after subjecting nickel or iron-nickel alloy to alkaline electrolytic degreasing.

(Second Embodiment) Among the stripping solutions for stripping a lead-free tin alloy on a nickel or iron nickel alloy of the present invention, the stripping solution for stripping a tin-bismuth alloy contains at least 35 to 420 mL of alkanesulfonic acid. / L, containing (meth) nitrobenzenesulfonic acid or a salt thereof in a range of 10 to 250 g / L, containing a halogen ion in a solubility range of 0.09 mol / L or more, and containing benzotriazole, At least one member selected from the group consisting of benzimidazole, imidazole and derivatives thereof
An aqueous solution containing g / L or more within the solubility range.

In the stripping solution of the present invention, if the alkanesulfonic acid content is less than 35 mL / L, the solubility of the tin-bismuth alloy layer is low, and the stripping rate is 1 μm / min or less, which is not practical. Becomes On the other hand, when the alkanesulfonic acid content exceeds 420 mL / L, tin-
The peeling rate of the bismuth alloy layer becomes 1 μm / min or less, and the concentration of (meth) nitrobenzenesulfonic acid or a salt thereof becomes higher than the solubility and does not dissolve. In the present invention, methanesulfonic acid, ethanesulfonic acid and the like can be used as the alkanesulfonic acid. For example, if 70% methanesulfonic acid is used, the content will be in the range of 50-600 mL / L.

In the stripping solution of the present invention, the content of (meth) nitrobenzenesulfonic acid or a salt thereof is 10 g /
If it is less than L, the solubility of the tin-bismuth alloy layer is low, and the peeling rate becomes 1 μm / min or less, which is not practical. In addition, if it exceeds 250 g / L, (meth)
The concentration of nitrobenzenesulfonic acid or a salt thereof becomes higher than the solubility, and the nitrobenzenesulfonic acid or the salt does not dissolve. As the above salts, sodium salts, potassium salts, ammonium salts and the like can be used.

In the stripping solution of the present invention, halogen ions are added for promoting the stripping of the nickel (iron-nickel alloy) -tin alloy layer existing under the tin-bismuth alloy layer. When chlorine ions are contained as halogen ions, sodium chloride, potassium chloride, hydrochloric acid, ammonium chloride and the like can be used as the chlorine source. When a fluorine ion is contained as a halogen ion, a fluorine source uses potassium fluoride, sodium fluoride, hydrofluoric acid, potassium hydrogen difluoride, sodium hydrogen difluoride, ammonium hydrogen difluoride, or the like. be able to. Further, when a bromine ion is contained as a halogen ion, potassium bromide, sodium bromide, ammonium bromide or the like can be used as a bromine source.

The content of halogen ions is 0.09 mol
When the ratio is less than / L, the nickel (iron-nickel alloy) -tin alloy layer present below the tin-bismuth alloy layer is insufficiently peeled off, and unpeeled nickel (iron-nickel alloy) on nickel or the iron-nickel alloy -The tin alloy layer will remain.

One or more components of the group consisting of benzotriazole, benzimidazole, imidazole and derivatives thereof contained in the stripping solution of the present invention have an effect of suppressing the dissolution rate of nickel or an iron-nickel alloy. is there. If the content of these components is less than 2 g / L, discoloration occurs in nickel and iron-nickel alloy and smut occurs, which is not preferable.

Further, the stripping solution of the present invention may contain a surfactant within a solubility range, if necessary. As the surfactant, a nonionic surfactant such as polyoxyethylene triol and polypropylene glycol, and an anionic surfactant such as potassium perfluoroalkyl sulfonate and sodium dioctyl sulfosuccinate can be used.

When the tin-bismuth alloy layer on nickel or an iron-nickel alloy is stripped using the stripping solution of the present invention as described above, the temperature of the stripping solution (treatment bath) is not particularly limited. For example, it can be set in the range of 20 to 60 ° C. The iron-nickel alloy is not particularly limited, and 42 materials (Fe: Ni =
58:42) and SUS316.

(Third Embodiment) Of the stripping solutions for stripping lead-free tin alloys on nickel or iron-nickel alloys of the present invention, the stripping solutions for stripping tin-silver alloys and tin-copper alloys are at least alkane sulfones. 35-350 mL of acid
/ L, (meth) nitrobenzenesulfonic acid or a salt thereof in the range of 5 to 250 g / L, and one of the group consisting of thiourea, alkylthiourea and aromatic thiourea. The above is contained in a solubility range of 20 g / L or more, and nitric acid is contained in an amount of 0.68 to 40.5 m.
An aqueous solution containing L / L.

In the stripping solution of the present invention, if the alkanesulfonic acid content is less than 35 mL / L, the solubility of the tin-silver alloy layer or the tin-copper alloy layer is low, and the stripping rate is 1 μm.
m / min or less and cannot be put to practical use. Also,
When the alkanesulfonic acid content exceeds 350 mL / L, the peeling rate of the tin-silver alloy layer or the tin-copper alloy layer is 1 μm.
m / min or less, and the concentration of (meth) nitrobenzenesulfonic acid or a salt thereof becomes higher than the solubility, and the compound does not dissolve. In the present invention, methanesulfonic acid, ethanesulfonic acid and the like can be used as the alkanesulfonic acid. For example, if 70% methanesulfonic acid is used, the content will be in the range of 50-500 mL / L.

In the stripping solution of the present invention, the content of (meth) nitrobenzenesulfonic acid or a salt thereof is 5 g / L.
If it is less than 1, the solubility of the tin-silver alloy layer or the tin-copper alloy layer is low, and the peeling rate is 1 μm / min or less, which is not practical. Also, if it exceeds 250 g / L,
The concentration of (meth) nitrobenzenesulfonic acid or a salt thereof becomes higher than the solubility, and the compound does not dissolve. As the above salts, sodium salts, potassium salts, ammonium salts and the like can be used.

In the stripping solution of the present invention, when the content of at least one component selected from the group consisting of thiourea, alkylthiourea and aromatic thiourea is less than 20 g / L, the color changes to nickel or an iron-nickel alloy. Undesirably, and smut occurs.

In the stripping solution of the present invention, when the content of nitric acid is less than 0.68 mL / L, the solubility of the tin-silver alloy layer or the tin-copper alloy layer is low, and the stripping speed becomes 1 μm / min or less. It will not be practical. Further, discoloration or smut occurs in nickel or iron-nickel alloy, which is not preferable. On the other hand, the nitrate content was 40.5 mL / L
If it exceeds, discoloration occurs in nickel or an iron-nickel alloy or smut occurs, which is not preferable. In the present invention, for example, 67.5% nitric acid can be used as nitric acid,
In this case, the content is in the range of 1 to 60 mL / L.

Further, the stripping solution of the present invention may contain a surfactant within a solubility range, if necessary. As the surfactant, a nonionic surfactant such as polyoxyethylene triol and polypropylene glycol, and an anionic surfactant such as potassium perfluoroalkyl sulfonate and sodium dioctyl sulfosuccinate can be used.

When a tin-silver alloy layer or a tin-copper alloy layer on nickel or an iron-nickel alloy is stripped by using the stripping solution of the present invention as described above, the temperature of the stripping solution (treatment bath) must be controlled. Although there is no particular limitation, for example, the temperature can be set in the range of 20 to 60 ° C.

There are no particular restrictions on the iron-nickel alloy.
42 materials used for lead frame (Fe: Ni = 5
8:42) and SUS316.
When a tin-silver alloy layer or a tin-copper alloy layer is formed by re-plating, it is preferable to form a lead-free tin alloy layer after subjecting nickel or an iron-nickel alloy to alkaline electrolytic degreasing.

[0041]

Next, the present invention will be described in more detail with reference to examples.

Example 1 Alkanesulfonic acid as 7
Using 0% methanesulfonic acid and sodium metanitrobenzenesulfonate, thiourea, 70%
13 kinds of aqueous solutions having the following compositions in which the concentration of methanesulfonic acid was variously set as shown in Table 1 below were prepared to obtain stripping solutions (samples 1-1 to 1-13).

Composition of stripper (samples 1-1 to 1-13): 70% methanesulfonic acid: concentration shown in Table 1; sodium metanitrobenzenesulfonate : 50 g / L; thiourea: 30 g / L; ion-exchanged water … Remainder Also, as a comparison, two kinds of stripping solutions having the following compositions (sample A,
B) was prepared.

Composition of stripping solution (sample A): trichloroacetic acid: 100 g / L thiourea: 20 g / L ion-exchanged water: balance

Composition of stripping solution (sample B): Trichloroacetic acid: 100 g / L Thiourea: 20 g / L Sulfamic acid: 40 g / L 67.5% nitric acid: 150 mL / L Ion exchanged water: Remainder

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-copper alloy layer having a thickness of μm. Using the above stripper (samples 1-1 to 1-13),
Bath temperature 40 ° C, bath load 0.5 dm ² / L, liquid volume 500
A treatment bath of mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-copper alloy layer. Further, using the stripping solution (samples A and B), a processing bath having a bath temperature of 40 ° C., a bath load of 0.5 dm ² / L, and a liquid volume of 500 mL was prepared.
The sample to be peeled was immersed in a bath to peel off the tin-copper alloy layer. The peeling rate of the tin-copper alloy layer, the dissolution rate of the 42 materials, and the appearance of the 42 materials after the peeling of the tin-copper alloy layer were measured and evaluated in these peeling treatments, and are shown in Table 1 below.

Further, after the tin-copper alloy layer was peeled off, the 42 material was subjected to alkaline electrolytic degreasing, and a 10-μm-thick tin-copper alloy layer was formed under the same conditions as described above. The appearance of the tin-copper alloy layer after heat treatment at 170 ° C. for 15 hours was evaluated, and the results are shown in Table 1 below.

[0048]

[Table 1]

As shown in Table 1, the stripping solution of the present invention containing methanesulfonic acid in the range of 35 to 420 mL / L (range of 50% to 600 mL / L as 70% methanesulfonic acid) (Sample 1-2) In any of Examples 1 to 12), the dissolution rate of the 42 material was 0.01 μm / min or less, which was good, even though the tin-copper alloy layer peeling rate exceeded 1 μm / min. In particular, methanesulfonic acid is 70-350m
L / L range (100% as 70% methanesulfonic acid)
(The range of 500 mL / L) of the stripping solution of the present invention (samples 1-3 to 1-11) has a tin-copper alloy layer stripping rate of 2 μm.
m / min. Moreover, the surface state of the 42 materials after the peeling of the tin-copper alloy layer was good without discoloration or smut generation. Furthermore, tin formed by replating
The appearance of the copper alloy layer was good without nodules, and the appearance of the tin-copper alloy layer after the heat treatment was good without any abnormality such as blisters.

On the other hand, in the case of the stripping solution (sample 1-1) in which the content of methanesulfonic acid is less than the range of the present invention,
The peeling speed of the tin-copper alloy layer was 1 μm / min or less.
Further, in the stripping solution (sample 1-13) in which the content of methanesulfonic acid exceeds the range of the present invention, it becomes difficult to dissolve 10 g / L or more of sodium metanitrobenzenesulfonate in the stripping solution. The peeling speed of the layer is 1
μm / min or less.

On the other hand, sample A, which is a conventional stripping solution, could not strip the tin-copper alloy layer, and the dissolution rate of the 42 material was as high as 0.04 μm / min. Further, in Sample B, which is a conventional stripping liquid, the tin-copper alloy layer peeling rate is large, and the surface state of the 42 material after the tin-copper alloy layer stripping is as follows.
There was no discoloration or smut generation, and the appearance of the tin-copper alloy layer formed by re-plating was good. But 4
The dissolution rate of the two materials was as large as 0.04 μm / min.

Example 2 Using 70% methanesulfonic acid as alkanesulfonic acid, sodium metanitrobenzenesulfonate and thiourea, various concentrations of sodium metanitrobenzenesulfonate were set as shown in Table 2 below. Then, 14 kinds of aqueous solutions having the following compositions were prepared to obtain stripping solutions (samples 2-1 to 2-14).

Composition of stripping solution (samples 2-1 to 2-14) 70% methanesulfonic acid 250 mL / L sodium metanitrobenzenesulfonate The concentration shown in Table 2 Thiourea 30 g / L ion-exchanged water … The rest

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-copper alloy layer having a thickness of μm. Using the above stripper (samples 2-1 to 2-14),
Bath temperature 40 ° C, bath load 0.5 dm ² / L, liquid volume 500
A treatment bath of mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-copper alloy layer. In this peeling treatment, the tin-copper alloy layer peeling speed, the 42 material dissolution speed,
The appearance of the 42 materials after peeling of the copper alloy layer was measured and evaluated, and the results are shown in Table 2 below.

After the tin-copper alloy layer was peeled off, 42 materials were subjected to alkaline electrolytic degreasing, and then a 10-μm-thick tin-copper alloy layer was formed under the same conditions as described above. The appearance and the appearance after further heat treatment at 170 ° C. for 15 hours were evaluated and are shown in Table 2 below.

[0056]

[Table 2]

As shown in Table 2, the stripping solution of the present invention containing sodium metanitrobenzenesulfonate in the range of 10 to 300 g / L (samples 2-3 to 2-13)
In each case, the peeling rate of the tin-copper alloy layer exceeded 2 μm / min. Although the tin-copper alloy layer peeling rate is high as described above, the dissolution rate of the 42 material is 0.01
μm / min or less, which was good. Moreover, the surface state of the 42 materials after the peeling of the tin-copper alloy layer was good without discoloration or smut generation. Furthermore, tin formed by replating
The appearance of the copper alloy layer was good without nodules, and the appearance of the tin-copper alloy layer after the heat treatment was good without any abnormality such as blisters.

On the other hand, in the stripping solution containing less than 10 g / L of sodium metanitrobenzenesulfonate (samples 2-1 and 2-2), the peeling speed of the tin-copper alloy layer is 1 μm / min or less. Met. In the case of a stripper having a sodium metanitrobenzenesulfonate content of more than 300 g / L (sample 2-14), tin-
The copper alloy layer remained, and could not be removed even by swinging.

Example 3 The following compositions were prepared by using 70% methanesulfonic acid as alkanesulfonic acid, sodium metanitrobenzenesulfonate, and thiourea and varying the concentration of thiourea as shown in Table 3 below. Were prepared to obtain stripping solutions (samples 3-1 to 3-13).

Composition of stripper (samples 3-1 to 3-7): 70% methanesulfonic acid: 220 mL / L sodium metanitrobenzenesulfonate : 50 g / L Thiourea: concentration shown in Table 3 Ion-exchanged water … The rest

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-copper alloy layer having a thickness of μm. Using the above stripper (samples 3-1 to 3-13),
Bath temperature 40 ° C, bath load 0.5 dm ² / L, liquid volume 500
A treatment bath of mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-copper alloy layer. In this peeling treatment, the tin-copper alloy layer peeling speed, the 42 material dissolution speed,
The appearance of the 42 materials after peeling of the copper alloy layer was measured and evaluated, and the results are shown in Table 3 below.

After peeling off the tin-copper alloy layer, the 42 material was subjected to alkaline electrolytic degreasing, and then a tin-copper alloy layer having a thickness of 10 μm was formed under the same conditions as above. The appearance of the layer and the appearance of the tin-copper alloy layer after further heat treatment at 170 ° C. for 15 hours were evaluated and are shown in Table 3 below.

[0063]

[Table 3]

As shown in Table 3, the amount of thiourea was 5 g /
Each of the stripping solutions of the present invention (samples 3-3 to 3-13) containing at least L and within the solubility range has a tin-copper alloy layer stripping rate of more than 3 μm / min, and contains 42 materials. Was 0.01 μm / min or less, which was good.
Moreover, the surface state of the 42 materials after the peeling of the tin-copper alloy layer was good without discoloration or smut generation. Further, the appearance of the tin-copper alloy layer formed by the replating was good without nodules, and the appearance of the tin-copper alloy layer after the heat treatment was good without any abnormalities such as blisters.

On the other hand, in the stripping solution containing no thiourea (sample 3-1), the stripping rate of the tin-copper alloy layer was 0.1 mm.
It was 1 μm / min or less, which was not practical. In addition, a stripper containing 1 g / L of thiourea (sample 3
-2) is good in that the peeling speed of the tin-copper alloy layer exceeds 1 μm / min, and the dissolution speed of the 42 material is 0.01 μm / min or less, which is good. Smut was generated on the surface of the material, and both could not be put to practical use. In the peeling of the tin-copper alloy layer, good results were obtained when the thiourea content was 5 g / L or more, and no further improvement was observed in the peeling performance when the thiourea content was 10 g / L or more.

Example 4 The stripping solution of Example 1 (Sample 1
Instead of 70% methanesulfonic acid which is the component of 6),
A stripper (sample 4) having the following composition using ethanesulfonic acid was prepared.

Composition of stripping solution (sample 4): ethanesulfonic acid: 250 mL / L sodium metanitrobenzenesulfonate: 50 g / L thiourea: 30 g / L ion-exchanged water: balance

Next, as the iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-copper alloy layer having a thickness of μm. Using the above stripper (sample 4), bath temperature 40 ° C,
A treatment bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-copper alloy layer. The peeling rate of the tin-copper alloy layer, the dissolution rate of the 42 materials, and the appearance of the 42 materials after the peeling of the tin-copper alloy layer were measured and evaluated in this peeling treatment. As a result, despite the sufficiently high peeling rate of the tin-copper alloy layer of 4.00 μm / min, the dissolution rate of 42 materials was 0.01 μm / min or less, which was good. In addition, after removing the tin-copper alloy layer,
The surface condition of the two materials was good without discoloration or smut occurrence.

Next, after the tin-copper alloy layer was peeled off, 42 materials were subjected to alkaline electrolytic degreasing, and then a 10 μm-thick tin-copper alloy layer was formed under the same conditions as described above.
Heat treatment was performed at 150C for 15 hours. The appearance of the tin-copper alloy layer formed by re-plating after peeling was good without nodules, and the appearance of the tin-copper alloy layer after heat treatment was good without any abnormalities such as blisters and the like. . From the above results, it was confirmed that, even when ethanesulfonic acid was used as the alkanesulfonic acid, a stripper having the same performance as the stripper using methanesulfonic acid described above was obtained.

Example 5 The stripping solution of Example 2 (sample 2
A stripper having the following composition (sample 5) using metanitrobenzenesulfonic acid instead of sodium metanitrobenzenesulfonate as the component 7) was prepared.

Composition of stripping solution (sample 5): 70% methanesulfonic acid: 250 mL / L; metanitrobenzenesulfonic acid: 50 g / L; thiourea: 30 g / L; ion-exchanged water: balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-copper alloy layer having a thickness of μm. Using the above stripper (sample 5), bath temperature 40 ° C,
A treatment bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-copper alloy layer. The peeling rate of the tin-copper alloy layer, the dissolution rate of the 42 materials, and the appearance of the 42 materials after the peeling of the tin-copper alloy layer were measured and evaluated in this peeling treatment. As a result, the peeling rate of the tin-copper alloy layer was 4.00 μm / min, which was sufficiently large, and the dissolution rate of 42 materials was 0.01 μm / min or less, which was good. On the other hand, the surface condition of the 42 material after the peeling of the tin-copper alloy layer was favorable without discoloration or occurrence of smut.

Next, after the tin-copper alloy layer was peeled off, 42 materials were subjected to alkaline electrolytic degreasing, and then a tin-copper alloy layer having a thickness of 10 μm was formed under the same conditions as described above.
Heat treatment was performed at 150C for 15 hours. The appearance of the tin-copper alloy layer formed by replating after peeling was good without nodules, and the appearance of the tin-copper alloy layer after heat treatment was good without any abnormality such as blisters. From the above results,
It was confirmed that even when using metanitrobenzenesulfonic acid, a stripper having the same performance as the stripper using sodium metanitrobenzenesulfonate described above was obtained.

Example 6 The stripping solution of Example 3 (sample 3
A stripper (sample 6) having the following composition using dimethylthiourea instead of thiourea as the component 7) was prepared.

Composition of stripping solution (sample 6): 70% methanesulfonic acid: 220 mL / L sodium metanitrobenzenesulfonate: 50 g / L Dimethylthiourea: 30 g / L Ion-exchanged water: balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-copper alloy layer having a thickness of μm. Using the above stripper (sample 6), bath temperature 40 ° C,
A treatment bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-copper alloy layer. The peeling rate of the tin-copper alloy layer, the dissolution rate of the 42 materials, and the appearance of the 42 materials after the peeling of the tin-copper alloy layer were measured and evaluated in this peeling treatment. As a result, the peeling rate of the tin-copper alloy layer was sufficiently large at 4.00 μm / min.
The dissolution rate of the two materials was 0.01 μm / min or less, which was good. Moreover, the surface state of the 42 materials after the peeling of the tin-copper alloy layer was good without discoloration or smut generation.

Next, after the tin-copper alloy layer was peeled off, 42 materials were subjected to alkaline electrolytic degreasing, and a tin-copper alloy layer having a thickness of 10 μm was formed under the same conditions as described above.
Heat treatment was performed at 150C for 15 hours. The appearance of the tin-copper alloy layer formed by replating after peeling was good without nodules, and the appearance of the tin-copper alloy layer after heat treatment was good without any abnormality such as blisters. From the above results,
It was confirmed that a stripper having the same performance as the stripper using thiourea was obtained when dimethylthiourea was used.

Example 7 First, a stripping solution (sample 7) having the same composition as the stripping solution of Example 1 (sample 1-6) was prepared.

Composition of stripping solution (sample 7): 70% methanesulfonic acid: 250 mL / L sodium metanitrobenzenesulfonate: 50 g / L Thiourea: 30 g / L Ion exchanged water: balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. and SUS3 manufactured by Nippon Metal Industry Co., Ltd.
16, a nickel material and an iron material were prepared, and a tin-copper alloy layer having a thickness of 10 μm was formed on these materials to prepare a sample to be peeled. Next, a processing bath having a bath temperature of 40 ° C., a bath load of 0.5 dm ² / L, and a liquid volume of 500 mL was prepared using the above-mentioned stripping solution (sample 7), and each sample to be stripped was immersed in the bath. Then, the tin-copper alloy layer was peeled off. In this peeling treatment, the tin-copper alloy layer peeling speed, material dissolution speed,
The appearance of the material after peeling the tin-copper alloy layer was measured and evaluated, and the results are shown in Table 4 below.

After peeling off the tin-copper alloy layer, the material was subjected to alkaline electrolytic degreasing, and then a tin-copper alloy layer having a thickness of 10 μm was formed under the same conditions as described above. The appearance of the tin-copper alloy layer after further heat treatment at 170 ° C. for 15 hours was evaluated and is shown in Table 4 below.

[0082]

[Table 4]

As shown in Table 4, the stripping solution of the present invention (Sample 7) has a tin-copper alloy layer peeling speed of 2.00 μm with respect to a sample to be stripped whose material is nickel or an iron-nickel alloy. / Min or more, and the dissolution rate of the material was sufficiently small and good. In addition, the surface state of the material after peeling the tin-copper alloy layer was good without discoloration or occurrence of smut. Further, the appearance of the tin-copper alloy layer formed by the replating was good without nodules, and the appearance of the tin-copper alloy layer after the heat treatment was good without any abnormalities such as blisters. In the sample to be peeled whose material is SUS316, although the surface state after peeling the tin-copper alloy layer has some surface roughness, replating after peeling and heat treatment have no problem. It is judged to be a practical level.

However, the dissolution rate of the iron material is as large as 2.91 μm / min for the sample to be peeled, which is made of an iron material.
Nodules were found in the tin-copper alloy layer formed by re-plating after peeling, and the heat treatment gave blisters in the tin-copper alloy layer.

Example 8 As alkanesulfonic acid, 7
Using 0% methanesulfonic acid, and using sodium metanitrobenzenesulfonate, sodium chloride and benzotriazole, the concentration of 70% methanesulfonic acid was variously set as shown in Table 5 below, and 13 kinds of the following compositions were used. An aqueous solution was prepared to obtain a stripping solution (samples 8-1 to 8-13).

Composition of stripping solution (samples 8-1 to 8-13): 70% methanesulfonic acid: concentration shown in Table 5 sodium metanitrobenzenesulfonate : 50 g / L sodium chloride: 30 g / L (chlorine concentration = 0.51mol / L) ・ Benzotriazole ・ ・ ・ 4g / L ・ Ion-exchanged water ・ ・ ・ The rest

For comparison, two kinds of stripping solutions (samples A and B) having the same composition as in Example 1 were prepared. Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used, and a 10 μm-thick tin-bismuth alloy layer was formed on the 42 materials to prepare a sample to be peeled.

Then, the above-mentioned stripping solution (samples 8-1 to 8-
13), bath temperature 40 ° C, bath load 0.5 dm ²
/ L, a treatment bath having a liquid volume of 500 mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-bismuth alloy layer. Further, using the stripping solution (samples A and B), a bath temperature of 40 ° C., a bath load of 0.5 dm ² / L, and a liquid volume of 500 m
A treatment bath of L was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-bismuth alloy layer. The peeling rate of the tin-bismuth alloy layer, the dissolution rate of the 42 material, and the appearance of the 42 material after the peeling of the tin-bismuth alloy layer in these peeling treatments were measured and evaluated.

After the tin-bismuth alloy layer is peeled off,
A tin-bismuth alloy layer having a thickness of 10 μm was formed under the same conditions as described above, and the appearance of the tin-bismuth alloy layer, and the appearance of the tin-bismuth alloy layer after further heat treatment at 170 ° C. for 15 hours. The results are shown in Table 5 below.

[0090]

[Table 5]

As shown in Table 5, the stripping solution of the present invention containing methanesulfonic acid in the range of 35 to 420 mL / L (50 to 600 mL / L as 70% methanesulfonic acid) (sample 8-2) No. 8-12), the dissolution rate of the 42 material was 0.01 despite the high peeling rate of the tin-bismuth alloy layer exceeding 2 μm / min.
μm / min or less, which was good. Further, the surface state of the 42 material after peeling the tin-bismuth alloy layer was good without discoloration or smut generation. Further, the appearance of the tin-bismuth alloy layer formed by re-plating was good without nodules, and the appearance of the tin-bismuth alloy layer after the heat treatment was good without any abnormalities such as blisters.

On the other hand, in the stripping solution (sample 8-1) in which the content of methanesulfonic acid is less than the range of the present invention,
The peeling speed of the tin-bismuth alloy layer was 1 μm / min or less. Further, in the stripping solution (sample 8-13) in which the content of methanesulfonic acid exceeds the range of the present invention, it becomes difficult to dissolve 10 g / L or more of sodium metanitrobenzenesulfonate in the stripping solution, and the tin-bismuth alloy The layer peeling rate was 1 μm / min or less. On the other hand, in the sample A which is a conventional stripper, the tin-bismuth alloy layer could not be stripped, and the dissolution rate of the 42 material was as high as 0.04 μm / min. In addition, a sample B which is a conventional stripper is used.
In this case, the peeling speed of the tin-bismuth alloy layer is high,
The surface state of the 42 material after the bismuth alloy layer was peeled was good without discoloration or smut occurrence. However, the tin-bismuth alloy layer formed by replating had poor adhesion.

Example 9 Using 70% methanesulfonic acid as an alkanesulfonic acid, sodium metanitrobenzenesulfonate, sodium chloride and benzotriazole, the concentration of sodium metanitrobenzenesulfonate was as shown in Table 6 below. 13 of the following composition set variously
Preparation of aqueous solution of seeds and stripping solution (samples 9-1 to 9-13)
I got

Composition of stripping solution (samples 9-1 to 9-13): 70% methanesulfonic acid: 150 mL / L sodium metanitrobenzenesulfonate : concentration shown in Table 6: sodium chloride: 30 g / L (chlorine concentration = 0.51mol / L) ・ Benzotriazole ・ ・ ・ 4g / L ・ Ion-exchanged water ・ ・ ・ The rest

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-bismuth alloy layer having a thickness of μm. Using the stripping solution (samples 9-1 to 9-13), a bath temperature of 40 ° C., a bath load of 0.5 dm ² / L, and a liquid volume of 5
A treatment bath of 00 mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-bismuth alloy layer. The peeling rate of the tin-bismuth alloy layer, the dissolution rate of the 42 material, and the appearance of the 42 material after the peeling of the tin-bismuth alloy layer in this peeling treatment were measured and evaluated, and are shown in Table 6 below. After peeling off the tin-bismuth alloy layer, a thickness of 10 mm was obtained under the same conditions as above.
A tin-bismuth alloy layer having a thickness of μm was formed, and the appearance of the tin-bismuth alloy layer and the appearance after further heat treatment at 170 ° C. for 15 hours were evaluated. The results are shown in Table 6 below.

[0096]

[Table 6]

As shown in Table 6, the stripping solution of the present invention containing sodium metanitrobenzenesulfonate in the range of 10 to 250 g / L (samples 9-3 to 9-12)
Indicates that the tin-bismuth alloy layer peeling rate is 2 μm
/ Min, and the dissolution rate of the 42 material is 0.01 despite the high peeling rate of the tin-bismuth alloy layer.
μm / min or less, which was good. Further, the surface state of the 42 material after peeling the tin-bismuth alloy layer was good without discoloration or smut generation. Further, the appearance of the tin-bismuth alloy layer formed by re-plating was good without nodules, and the appearance of the tin-bismuth alloy layer after the heat treatment was good without any abnormalities such as blisters.

On the other hand, a stripper having a content of sodium metanitrobenzenesulfonate of less than 10 g / L (sample 9
In (-1, 9-2), the peeling rate of the tin-bismuth alloy layer was 1 μm / min or less. In sample 9-13,
The amount of sodium metanitrobenzenesulfonate added exceeded the solubility, and excess sodium metanitrobenzenesulfonate precipitated in the bath, resulting in material loss.

Example 10 Using sodium chloride as a chlorine source and 70% methanesulfonic acid, sodium metanitrobenzenesulfonate, and benzotriazole, the chloride ion concentration was as shown in Table 7 below. Thirteen types of aqueous solutions having various compositions described below were prepared to obtain stripping solutions (samples 10-1 to 10-13).

Composition of stripping solution (samples 10-1 to 10-13): 70% methanesulfonic acid: 220 mL / L sodium metanitrobenzenesulfonate: 50 g / L chloride ion (supply source: sodium chloride) Table 7・ Benzotriazole: 4 g / L ・ Ion-exchanged water: balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-bismuth alloy layer having a thickness of μm. Using the above stripping solution (samples 10-1 to 10-13), a treatment bath having a bath temperature of 40 ° C., a bath load of 0.5 dm ² / L, and a liquid volume of 500 mL was prepared, and the above-mentioned peeling was performed in the bath. The sample was immersed to peel off the tin-bismuth alloy layer. The peeling speed of the tin-bismuth alloy layer in this peeling treatment is 4
The dissolution rate of the two materials and the appearance of the 42 materials after peeling the tin-bismuth alloy layer were measured and evaluated, and are shown in Table 7 below. Further, after the tin-bismuth alloy layer was peeled off, a tin-bismuth alloy layer having a thickness of 10 μm was formed under the same conditions as described above.
The appearance of the bismuth alloy layer and the appearance of the tin-bismuth alloy layer after further heat treatment at 170 ° C. for 15 hours were evaluated and are shown in Table 7 below.

[0102]

[Table 7]

As shown in Table 7, the stripping solution of the present invention having a chlorine ion concentration of 0.09 mol / L (sodium chloride concentration 5 g / L) or more and within the solubility range (sample 10-2)
In all cases, the peeling rates of the tin-bismuth alloy layers exceeded 4 μm / min. Despite the high tin-bismuth alloy layer peeling rate,
The dissolution rate of the 42 materials was 0.01 μm / min or less, which was good. Further, the surface state of the 42 material after peeling the tin-bismuth alloy layer was good without discoloration or smut generation.
Further, the appearance of the tin-bismuth alloy layer formed by re-plating was good without nodules, and the appearance of the tin-bismuth alloy layer after the heat treatment was good without any abnormalities such as blisters.

On the other hand, the stripping solution containing no chlorine ion (sample 10-1) was not able to strip the tin-bismuth alloy layer. The chlorine ion concentration is 0.02m
In the case of the ol / L stripping solution (sample 10-2), the tin-bismuth alloy layer stripping speed exceeds 2 μm / min, and
The dissolution rate of the two materials was 0.01 μm / min or less, which was good. However, smut was generated on the surface of the 42 materials after the tin-bismuth alloy layer was peeled off, and both were not practically usable.
In the peeling of the tin-bismuth alloy layer, good results were obtained when the chloride ion concentration was 0.09 mol / L (sodium chloride concentration 5 g / L) or more, and 0.26 mol / L (sodium chloride concentration 15 g / L) or more. No further improvement in peeling performance was observed.

Example 11 Using 70% methanesulfonic acid as alkanesulfonic acid, sodium metanitrobenzenesulfonate, sodium chloride and benzotriazole, the concentration of benzotriazole was variously set as shown in Table 8 below. Nine kinds of aqueous solutions having the following compositions were prepared to obtain stripping solutions (samples 11-1 to 11-9).

Composition of stripper (samples 11-1 to 11-9): 70% methanesulfonic acid: 220 mL / L sodium metanitrobenzenesulfonate : 50 g / L sodium chloride: 30 g / L (chlorine concentration = 0. (51 mol / L) ・ Benzotriazole ... concentration shown in Table 8 ・ Ion-exchanged water ... balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-bismuth alloy layer having a thickness of μm. Using the above stripping solution (samples 11-1 to 11-9), a treatment bath having a bath temperature of 40 ° C., a bath load of 0.5 dm ² / L, and a liquid volume of 500 mL was prepared. The sample was immersed to peel off the tin-bismuth alloy layer. The peeling rate of the tin-bismuth alloy layer in this peeling treatment, 42
The material dissolution rate and the appearance of the 42 materials after peeling off the tin-bismuth alloy layer were measured and evaluated, and are shown in Table 8 below. In addition, tin
After the bismuth alloy layer is peeled off, a thickness of 1
A tin-bismuth alloy layer having a thickness of 0 μm was formed, and the appearance of the tin-bismuth alloy layer and the appearance after further heat treatment at 170 ° C. for 15 hours were evaluated. The results are shown in Table 8 below.

[0108]

[Table 8]

As shown in Table 8, the stripping solutions of the present invention (samples 11-2 to 11-8) containing benzotriazole at a concentration of 2 g / L or more and within the solubility range were all tin-based.
Bismuth alloy layer peeling speed is as large as 3 μm / min, and
The dissolution rate of the 42 materials was 0.01 μm / min or less, which was good. Further, the surface state of the 42 material after peeling the tin-bismuth alloy layer was good without discoloration or smut generation.
Further, the appearance of the tin-bismuth alloy layer formed by the replating was good without nodules, and the appearance of the tin-bismuth alloy layer after the heat treatment was good without any abnormality such as blisters.

On the other hand, in the stripping solution (sample 11-1) having a benzotriazole content of less than 2 g / L,
Peeling of the tin-bismuth alloy layer was impossible. Also,
In sample 11-9, the amount of benzotriazole added was higher than the solubility, and excess benzotriazole was precipitated in the bath, resulting in increased costs due to material loss. Therefore, in this example, it is preferable to set the concentration of benzotriazole in the range of 2 to 50 g / L.

Example 12 The stripping solution of Example 8 (sample 8
A stripper (sample 12) having the following composition and using potassium fluoride instead of sodium chloride as the component -4) was prepared.

Composition of stripping solution (sample 12): 70% methanesulfonic acid: 150 mL / L sodium metanitrobenzenesulfonate: 50 g / L Potassium fluoride: 10 g / L (fluorine ion = 0.18 mol / L) Benzotriazole: 4 g / L ・ Ion-exchanged water: balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-bismuth alloy layer having a thickness of μm. Using the above stripper (sample 12), bath temperature 4
A processing bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared at 0 ° C., and the sample to be peeled was immersed in the bath to peel off the tin-bismuth alloy layer. The peeling rate of the tin-bismuth alloy layer, the dissolution rate of the 42 material, and the appearance of the 42 material after the peeling of the tin-bismuth alloy layer in this peeling treatment were measured and evaluated. As a result, the tin-bismuth alloy layer peeling speed was 5.
71 μm / min was sufficiently large, and the dissolution rate of 42 materials was 0.01 μm / min or less, which was good. further,
The surface state of the 42 materials after the peeling of the tin-bismuth alloy layer was good without discoloration or smut generation.

Next, after peeling the tin-bismuth alloy layer,
Under the same conditions as above, a tin-bismuth alloy layer having a thickness of 10 μm was formed, and further subjected to a heat treatment at 170 ° C. for 15 hours. The appearance of the tin-bismuth alloy layer formed by re-plating after peeling was good without nodules, and the appearance of the tin-bismuth alloy layer after heat treatment was good without any abnormalities such as blisters. From the above results, it was confirmed that even when fluorine ions were used as the halogen ions, a stripping solution having the same performance as the stripping solution using the above-described chlorine ions was obtained.

Example 13 The stripping solution of Example 8 (sample 8
A stripper having the following composition (sample 13) using potassium bromide instead of sodium chloride as the component -4) was prepared.

Composition of stripping solution (sample 13): 70% methanesulfonic acid: 150 mL / L sodium metanitrobenzenesulfonate: 50 g / L Potassium bromide: 11 g / L (bromine ion = 0.09 mol / L) Benzotriazole: 4 g / L ・ Ion-exchanged water: balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-bismuth alloy layer having a thickness of μm. Using the above stripping solution (sample 13), bath temperature 4
A processing bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared at 0 ° C., and the sample to be peeled was immersed in the bath to peel off the tin-bismuth alloy layer. The peeling rate of the tin-bismuth alloy layer, the dissolution rate of the 42 material, and the appearance of the 42 material after the peeling of the tin-bismuth alloy layer in this peeling treatment were measured and evaluated. As a result, the tin-bismuth alloy layer peeling speed was 5.
71 μm / min is sufficiently large, and the dissolution rate of 42 materials is 0.1 μm.
It was good because it was 01 μm / min or less. Further, the surface state of the 42 material after peeling the tin-bismuth alloy layer was good without discoloration or smut generation.

Next, after peeling the tin-bismuth alloy layer,
Under the same conditions as above, a tin-bismuth alloy layer having a thickness of 10 μm was formed, and further subjected to a heat treatment at 170 ° C. for 15 hours. The appearance of the tin-bismuth alloy layer formed by re-plating after peeling was good without nodules, and the appearance of the tin-bismuth alloy layer after heat treatment was good without any abnormalities such as blisters. From the above results, it was confirmed that even when bromine ions were used as the halogen ions, a stripping solution having the same performance as the stripping solution using the above-described chlorine ions was obtained.

[Example 14] The stripping solution of Example 8 (sample 8
A stripper (sample 14) having the following composition using ethanesulfonic acid instead of 70% methanesulfonic acid as the component of -4) was prepared.

Composition of stripping solution (sample 14): ethanesulfonic acid: 150 mL / L sodium metanitrobenzenesulfonate: 50 g / L sodium chloride: 30 g / L (chlorine concentration = 0.51 mol / L) benzotriazole: 4g / L ・ Ion-exchanged water ... balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-bismuth alloy layer having a thickness of μm. Using the above stripper (sample 14), bath temperature 4
A processing bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared at 0 ° C., and the sample to be peeled was immersed in the bath to peel off the tin-bismuth alloy layer. The peeling rate of the tin-bismuth alloy layer, the dissolution rate of the 42 material, and the appearance of the 42 material after the peeling of the tin-bismuth alloy layer in this peeling treatment were measured and evaluated. As a result, the tin-bismuth alloy layer peeling speed was 5.
71 μm / min is sufficiently large, and the dissolution rate of 42 materials is 0.1 μm.
It was good because it was 01 μm / min or less. Further, the surface state of the 42 material after peeling the tin-bismuth alloy layer was good without discoloration or smut generation.

Next, after peeling the tin-bismuth alloy layer,
Under the same conditions as above, a tin-bismuth alloy layer having a thickness of 10 μm was formed, and further subjected to a heat treatment at 170 ° C. for 15 hours. The appearance of the tin-bismuth alloy layer formed by re-plating after peeling was good with no nodules, and the appearance of the tin-bismuth alloy layer after heat treatment was good without any abnormalities such as blisters. From the above results, it was confirmed that, even when ethanesulfonic acid was used as the alkanesulfonic acid, a stripper having the same performance as the stripper using methanesulfonic acid described above was obtained.

[Example 15] The stripping solution of Example 9 (sample 9
A stripper having the following composition (sample 15) using metanitrobenzenesulfonic acid instead of sodium metanitrobenzenesulfonate which is the component of -7) was prepared.

Composition of stripping solution (sample 15) 70% methanesulfonic acid 150 mL / L metanitrobenzenesulfonic acid 50 g / L Sodium chloride 30 g / L (chlorine concentration = 0.51 mol / L) Benzotriazole … 4g / L ・ Ion-exchanged water… balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-bismuth alloy layer having a thickness of μm. Using the above stripper (sample 15), bath temperature 4
A processing bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared at 0 ° C., and the sample to be peeled was immersed in the bath to peel off the tin-bismuth alloy layer. The peeling rate of the tin-bismuth alloy layer, the dissolution rate of the 42 material, and the appearance of the 42 material after the peeling of the tin-bismuth alloy layer in this peeling treatment were measured and evaluated. As a result, the tin-bismuth alloy layer peeling speed was 5.
71 μm / min was sufficiently large, and the dissolution rate of 42 materials was 0.01 μm / min or less, which was good. Further, the surface state of the 42 material after peeling the tin-bismuth alloy layer was good without discoloration or smut generation.

Next, after peeling the tin-bismuth alloy layer,
Under the same conditions as above, a tin-bismuth alloy layer having a thickness of 10 μm was formed, and further subjected to a heat treatment at 170 ° C. for 15 hours. As a result, the appearance of the tin-bismuth alloy layer formed by replating after peeling was good without nodules,
The appearance of the tin-bismuth alloy layer after the heat treatment was good without any abnormality such as blisters. From the above results, it was confirmed that even when metanitrobenzenesulfonic acid was used, a stripper having the same performance as the stripper using sodium metanitrobenzenesulfonate described above was obtained.

Example 16 A stripper having the following composition (sample 1) was prepared by using imidazole instead of benzotriazole as a component of the stripper (sample 11-3) of Example 11.
6) was prepared.

Composition of stripping solution (sample 16): 70% methanesulfonic acid: 220 mL / L sodium metanitrobenzenesulfonate: 50 g / L sodium chloride: 30 g / L (chlorine concentration = 0.51 mol / L) imidazole … 4g / L ・ Ion-exchanged water… balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-bismuth alloy layer having a thickness of μm. Using the above stripper (sample 16), bath temperature 4
A processing bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared at 0 ° C., and the sample to be peeled was immersed in the bath to peel off the tin-bismuth alloy layer. The peeling rate of the tin-bismuth alloy layer, the dissolution rate of the 42 material, and the appearance of the 42 material after the peeling of the tin-bismuth alloy layer in this peeling treatment were measured and evaluated. As a result, the tin-bismuth alloy layer peeling speed was 5.
71 μm / min is sufficiently large, and the dissolution rate of 42 materials is 0.1 μm.
It was good because it was 01 μm / min or less. Further, the surface state of the 42 material after peeling the tin-bismuth alloy layer was good without discoloration or smut generation.

Next, after peeling the tin-bismuth alloy layer,
Under the same conditions as above, a tin-bismuth alloy layer having a thickness of 10 μm was formed, and further subjected to a heat treatment at 170 ° C. for 15 hours. The appearance of the tin-bismuth alloy layer formed by re-plating after peeling was good without nodules, and the appearance of the tin-bismuth alloy layer after heat treatment was good without any abnormalities such as blisters. From the above results, it was confirmed that even when imidazole was used, a stripper having the same performance as the stripper using benzotriazole was obtained.

Example 17 First, a stripping solution (Sample 17) having the same composition as the stripping solution of Example 8 (Sample 8-4) was prepared.

Composition of stripper (sample 17) 70% methanesulfonic acid 150 mL / L sodium metanitrobenzenesulfonate 50 g / L sodium chloride 30 g / L (chlorine concentration = 0.51 mol / L) Benzo Triazole 4g / L ・ Ion-exchanged water… balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. and SUS3 manufactured by Nippon Metal Industry Co., Ltd.
16, a nickel material and an iron material were prepared, and a 10 μm-thick tin-bismuth alloy layer was formed on these materials to prepare a sample to be peeled. Next, the above-mentioned stripping solution (sample 1
7) using a bath temperature of 40 ° C. and a bath load of 0.5 dm ² /
L, a treatment bath having a liquid volume of 500 mL was prepared, and each of the samples to be peeled was immersed in the bath to peel off the tin-bismuth alloy layer. The peeling rate of the tin-bismuth alloy layer, the material dissolution rate, and the appearance of the material after peeling the tin-bismuth alloy layer in this peeling treatment were measured and evaluated. Also,
After peeling off the tin-bismuth alloy layer, a tin-bismuth alloy layer having a thickness of 10 μm was formed under the same conditions as above, and the appearance of the tin-bismuth copper alloy layer was further reduced to 170 ° C.
The appearance of the tin-bismuth alloy layer after the heat treatment for 5 hours was evaluated and the results are shown in Table 9 below.

[0134]

[Table 9]

As shown in Table 9, the stripping solution of the present invention (sample 17) has a tin-bismuth alloy layer peeling rate of 2.85 μm with respect to the sample to be stripped whose material is nickel or an iron-nickel alloy. / Min or more, and the dissolution rate of the material was sufficiently small and good. The surface condition of the material after peeling the tin-bismuth alloy layer was good without discoloration or smut generation. Further, the appearance of the tin-bismuth alloy layer formed by re-plating was good without nodules, and the appearance of the tin-bismuth alloy layer after the heat treatment was good without any abnormalities such as blisters. In the sample to be peeled whose material is SUS316, although the surface state after peeling off the tin-bismuth alloy layer shows some surface roughness, there is no problem in re-plating after peeling and heat treatment. It is judged to be a practical level.

However, the dissolution rate of the iron material was as large as 2.91 μm / min with respect to the sample to be peeled made of the iron material.
Nodules are found in the tin-bismuth alloy layer formed by re-plating after peeling, resulting in surface roughness.
The heat treatment caused blisters in the tin-bismuth alloy layer.

[Example 18] 70% methanesulfonic acid was used as alkanesulfonic acid, and sodium metanitrobenzenesulfonate, thiourea and 67.5% nitric acid were used to reduce the concentration of 70% methanesulfonic acid. Twelve kinds of aqueous solutions having the following compositions which were variously set as shown in Table 10 below were prepared to obtain stripping solutions (samples 18-1 to 18-12).

Composition of stripping solution (samples 18-1 to 18-12) 70% methanesulfonic acid: concentration shown in Table 10 sodium metanitrobenzenesulfonate : 50 g / L thiourea: 30 g / L 67.5 % Nitric acid… 20mL / L ・ Ion exchange water… The rest

As a comparison, two kinds of stripping solutions (samples A and B) having the same composition as in Example 1 were prepared. next,
As the iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used, and a 10 μm-thick tin-silver alloy layer was formed on the 42 materials to prepare a sample to be peeled.

The above stripper (samples 18-1 to 18-1)
Using 2), bath temperature 40 ° C, bath load 0.5 dm ² /
L, a processing bath having a liquid volume of 500 mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-silver alloy layer. Further, using the above-mentioned stripping solution (samples A and B), and using a bath temperature of 40
A treatment bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared, and the sample to be peeled was immersed in the bath.
The silver alloy layer was peeled off. The peeling rate of the tin-silver alloy layer, the dissolution rate of the 42 materials, and the appearance of the 42 materials after the peeling of the tin-silver alloy layer were measured and evaluated in these peeling treatments, and the results are shown in Table 1 below.
It was shown to.

After the tin-silver alloy layer was peeled off, 42 materials were subjected to alkaline electrolytic degreasing, and then a tin-silver alloy layer having a thickness of 10 μm was formed under the same conditions as described above. The appearance and the appearance of the tin-silver alloy layer after further heat treatment at 170 ° C. for 15 hours were evaluated and are shown in Table 10 below.

[0142]

[Table 10]

As shown in Table 10, the stripping solution of the present invention (sample 18-2) containing methanesulfonic acid in the range of 35 to 350 mL / L (50 to 500 mL / L as 70% methanesulfonic acid). In any of Examples Nos. To 18-11), the dissolution rate of the 42 material was 0.01 μm / min or less, which was good, though the tin-silver alloy layer peeling rate exceeded 1 μm / min. In particular, methanesulfonic acid is 70-
The stripping solution of the present invention (samples 18-3 to 18-11) in the range of 350 mL / L (the range of 100 to 500 mL / L as 70% methanesulfonic acid) has a tin-silver alloy layer peeling rate of 4 μm / It was expensive for more than a minute. Also,
The surface state of the 42 materials after the peeling of the tin-silver alloy layer was good without discoloration or occurrence of smut. Furthermore, the appearance of the tin-silver alloy layer formed by re-plating was good without nodules, and the appearance of the tin-silver alloy layer after the heat treatment was good without any abnormalities such as blisters.

On the other hand, the content of methanesulfonic acid was 35 mL / L (50% as 70% methanesulfonic acid).
(L / L), the stripping rate of the tin-silver alloy layer was 1 μm / min or less in the stripping solution (sample 18-1). Moreover, in the case of the stripping solution (sample 18-12) in which the content of methanesulfonic acid exceeds the range of the present invention, bath decomposition occurred during bathing, and building bath was impossible.

On the other hand, in the sample A which is a conventional stripping solution, the tin-silver alloy layer could not be stripped, and the dissolution rate of the 42 material was as large as 0.04 μm / min. Also, in Sample B, which is a conventional stripping solution, although the tin-silver alloy layer stripping rate is high, the dissolution rate of the 42 material at the time of stripping the tin-silver alloy layer is so large that it cannot be measured due to excessive reaction. there were. The surface state of the 42 material after peeling was rough, and the appearance of the tin-silver alloy layer formed by re-plating was poor.

Example 19 Using 70% methanesulfonic acid as alkanesulfonic acid, sodium metanitrobenzenesulfonate, thiourea and 67.5% nitric acid, the concentration of sodium metanitrobenzenesulfonate was determined in the following table. Preparation of 13 types of aqueous solutions having the following compositions variously set as in Example 11 and stripping solutions (Samples 19-1 to 19-13)
I got

Composition of stripping solution (samples 19-1 to 19-13): 70% methanesulfonic acid: 200 mL / L sodium metanitrobenzenesulfonate : concentration shown in Table 11; thiourea: 30 g / L; 67.5 % Nitric acid… 20mL / L ・ Ion exchange water… The rest

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-silver alloy layer of μm. Using the above-mentioned stripping solution (samples 19-1 to 19-13), bath temperature 40 ° C., bath load 0.5 dm ² / L, liquid volume 5
A treatment bath of 00 mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-silver alloy layer. The peeling rate of the tin-silver alloy layer, the dissolution rate of the 42 materials, and the appearance of the 42 materials after the peeling of the tin-silver alloy layer in this peeling treatment were measured and evaluated, and are shown in Table 11 below.

Further, after the tin-silver alloy layer was peeled off, the 42 material was subjected to alkaline electrolytic degreasing, and then a tin-silver alloy layer having a thickness of 10 μm was formed under the same conditions as described above. The appearance and the appearance after further heat treatment at 170 ° C. for 15 hours were evaluated and are shown in Table 11 below.

[0150]

[Table 11]

As shown in Table 11, the stripping solution of the present invention containing sodium metanitrobenzenesulfonate in the range of 5 to 250 g / L (samples 19-2 to 19-1)
2) In all cases, the tin-silver alloy layer peeling speed was 3 μm /
Over a minute. In spite of the high peeling rate of the tin-silver alloy layer, the dissolution rate of the 42 material was 0.1 mm.
It was good because it was 01 μm / min or less. Further, the surface state of the 42 materials after peeling of the tin-silver alloy layer was good without discoloration or smut generation. Furthermore, the appearance of the tin-silver alloy layer formed by re-plating was good without nodules, and the appearance of the tin-silver alloy layer after the heat treatment was good without any abnormalities such as blisters.

On the other hand, in the stripping solution (sample 19-1) in which the content of sodium metanitrobenzenesulfonate is less than 5 g / L, the stripping speed of the tin-silver alloy layer is 1%.
μm / min or less. In the case of a stripper having a sodium metanitrobenzenesulfonate content of more than 250 g / L (samples 19 to 13), a tin-silver alloy layer remained on the surface of the 42 material and could not be removed even if it was swung.

[Example 20] Using 70% methanesulfonic acid as alkanesulfonic acid, sodium metanitrobenzenesulfonate, thiourea and 67.5% nitric acid, the concentration of thiourea is shown in Table 12 below. , 13 types of aqueous solutions having the following compositions which were variously set were prepared to obtain stripping solutions (samples 20-1 to 20-13).

Composition of stripping solution (samples 20-1 to 20-13): 70% methanesulfonic acid: 220 mL / L sodium metanitrobenzenesulfonate : 50 g / L Thiourea: concentration shown in Table 12: 67.5 % Nitric acid… 20mL / L ・ Ion exchange water… The rest

Next, as the iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-silver alloy layer of μm. A bath temperature of 40 ° C., a bath load of 0.5 dm ² / L, and a liquid volume of 5 using the above-mentioned stripping solution (samples 20-1 to 20-13)
A treatment bath of 00 mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-silver alloy layer. The peeling rate of the tin-silver alloy layer, the dissolution rate of the 42 material, and the appearance of the 42 material after the peeling of the tin-silver alloy layer in this peeling treatment were measured and evaluated, and are shown in Table 12 below.

After the tin-silver alloy layer was peeled off, the 42 material was subjected to alkaline electrolytic degreasing, and then a tin-silver alloy layer having a thickness of 10 μm was formed under the same conditions as described above. The appearance of the layer and the appearance of the tin-silver alloy layer after further heat treatment at 170 ° C. for 15 hours were evaluated and are shown in Table 12 below.

[0157]

[Table 12]

As shown in Table 12, thiourea contained 20
Each of the stripping solutions of the present invention (samples 20-6 to 20-13) containing g / L or more in the solubility range had a tin-silver alloy layer stripping rate of more than 7 µm / min. Thus, despite the high peeling rate of the tin-silver alloy layer, the dissolution rate of the 42 material was 0.01 μm / min or less, which was good. Further, the surface state of the 42 materials after peeling of the tin-silver alloy layer was good without discoloration or smut generation. Furthermore, the appearance of the tin-silver alloy layer formed by re-plating was good without nodules, and the appearance of the tin-silver alloy layer after the heat treatment was good without any abnormalities such as blisters.

On the other hand, when the thiourea content was 5 g / L
In the following stripping solutions (samples 20-1 to 20-3), the stripping speed of the tin-silver alloy layer is 0.1 μm / min or less,
Smut was generated on the surface of the 42 material after the tin-silver alloy layer was peeled off, which was not practical. A stripper containing 10 to 15 g / L of thiourea (samples 20-4 and 20
-5) is good because the peeling speed of the tin-silver alloy layer is about 6 μm / min and the dissolution rate of the 42 material is 0.01 μm / min or less, but the surface of the 42 material after peeling the tin-silver alloy layer is good. And smut was generated, and both could not be put to practical use.
The tin-silver alloy layer was peeled off when the thiourea content was 20 g.
/ L or more gave good results, and no further improvement in peeling performance was observed even when the added amount was increased.

Example 21 Using 70% methanesulfonic acid as alkanesulfonic acid, sodium metanitrobenzenesulfonate, thiourea and 67.5% nitric acid, the concentration of 67.5% nitric acid was determined as shown in Table 13 below. As shown in Table 3, 11 kinds of aqueous solutions having various compositions shown below were prepared to obtain stripping solutions (samples 21-1 to 21-11).

Composition of stripper (samples 21-1 to 21-11): 70% methanesulfonic acid: 220 mL / L sodium metanitrobenzenesulfonate: 50 g / L thiourea: 30 g / L 67.5% nitric acid … Concentration shown in Table 13 ・ Ion-exchanged water… Remainder

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-silver alloy layer of μm. Using the above-mentioned stripping solution (samples 21-1 to 21-11), bath temperature 40 ° C, bath load 0.5 dm ² / L, liquid volume 5
A treatment bath of 00 mL was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-silver alloy layer. The peeling rate of the tin-silver alloy layer, the dissolution rate of the 42 materials, and the appearance of the 42 materials after the peeling of the tin-silver alloy layer in this peeling treatment were measured and evaluated, and are shown in Table 13 below.

After the tin-silver alloy layer was peeled off, 42 materials were subjected to alkaline electrolytic degreasing, and then a tin-silver alloy layer having a thickness of 10 μm was formed under the same conditions as described above. The appearance of the layer and the appearance of the tin-silver alloy layer after further heat treatment at 170 ° C. for 15 hours were evaluated and are shown in Table 13 below.

[0164]

[Table 13]

As shown in Table 13, the nitric acid content was 0.68.
４40.5 mL / L (1 as 67.5% nitric acid)
(In the range of ６０60 mL / L) of the present invention (samples 21-2 to 21-10) all had a tin-silver alloy layer peeling rate of more than 4 μm / min. In spite of the high peeling rate of the tin-silver alloy layer, 4
The dissolution rate of the two materials was 0.01 μm / min or less, which was good. Further, the surface state of the 42 materials after peeling of the tin-silver alloy layer was good without discoloration or smut generation. further,
The appearance of the tin-silver alloy layer formed by the re-plating was good without nodules, and the appearance of the tin-silver alloy layer after the heat treatment was good without any abnormalities such as blisters.

On the other hand, the nitric acid content was 0.68 mL /
In the stripping solution (sample 21-1) having a tin-silver alloy layer separation rate of less than 0.1 L / min (less than 1 mL / L as 67.5% nitric acid), the tin-silver alloy layer separation rate was 0.1 μm / min or less. Smut was generated on the surface of the later 42 materials, which was not practical. The nitric acid content was 40.5 mL / L (6
The stripping liquid (sample 21-11) exceeding 7.5 mL of 7.5% nitric acid has a tin-silver alloy layer peeling rate of 13 μm.
/ Min, but the dissolution rate of 42 materials is 0.01 μm /
Min, and smut was generated on the surface of the 42 material after the tin-silver alloy layer was peeled off, which was not practical.

Example 22 A stripper (sample 22) having the following composition was prepared using ethanesulfonic acid instead of 70% methanesulfonic acid, which is a component of the stripper (sample 18-5) of Example 18. did.

Composition of stripping solution (sample 22): ethanesulfonic acid: 200 mL / L sodium metanitrobenzenesulfonate: 50 g / L thiourea: 30 g / L 67.5% nitric acid: 20 mL / L ion-exchanged water … The rest

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-silver alloy layer of μm. Using the above stripper (sample 22), bath temperature 40
A treatment bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared, and the sample to be peeled was immersed in the bath.
The silver alloy layer was peeled off. Tin in this stripping process
The peeling speed of the silver alloy layer, the dissolution speed of the 42 materials, and the appearance of the 42 materials after the peeling of the tin-silver alloy layer were measured and evaluated. As a result, the peeling rate of the tin-silver alloy layer was sufficiently high at 7.06 μm / min, and the dissolution rate of the 42 materials was 0.01 μm / min or less, which was good. Further, the surface state of the 42 materials after peeling of the tin-silver alloy layer was good without discoloration or smut generation.

Next, after the tin-silver alloy layer was peeled off, 42 materials were subjected to alkaline electrolytic degreasing, and a tin-silver alloy layer having a thickness of 10 μm was formed under the same conditions as described above.
Heat treatment was performed at 150C for 15 hours. The appearance of the tin-silver alloy layer formed by re-plating after peeling was good without nodules, and the appearance of the tin-silver alloy layer after heat treatment was good without any abnormalities such as blisters. From the above results,
It was confirmed that, even when ethanesulfonic acid was used as the alkanesulfonic acid, a stripper having the same performance as that of the above-mentioned stripper using methanesulfonic acid was obtained.

Example 23 A stripper having the following composition (sample 23) using metanitrobenzenesulfonic acid instead of sodium metanitrobenzenesulfonate as a component of the stripper (sample 19-7) of Example 19 was used. Prepared.

Composition of stripping solution (Sample 23) 70% methanesulfonic acid: 200 mL / L Metanitrobenzenesulfonic acid: 50 g / L Thiourea: 30 g / L 67.5% nitric acid: 20 mL / L Ion exchange Water… the rest

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-silver alloy layer of μm. Using the above stripper (sample 23), bath temperature 40
A treatment bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared, and the sample to be peeled was immersed in the bath.
The silver alloy layer was peeled off. Tin in this stripping process
The peeling speed of the silver alloy layer, the dissolution speed of the 42 materials, and the appearance of the 42 materials after the peeling of the tin-silver alloy layer were measured and evaluated. As a result, the peeling rate of the tin-silver alloy layer was sufficiently high at 7.06 μm / min, and the dissolution rate of the 42 materials was 0.01 μm / min or less, which was good. Further, the surface state of the 42 materials after peeling of the tin-silver alloy layer was good without discoloration or smut generation.

Next, after the tin-silver alloy layer was peeled off, 42 materials were subjected to alkaline electrolytic degreasing, and a tin-silver alloy layer having a thickness of 10 μm was formed under the same conditions as described above.
Heat treatment was performed at 150C for 15 hours. The appearance of the tin-silver alloy layer formed by re-plating after peeling was good without nodules, and the appearance of the tin-silver alloy layer after heat treatment was good without any abnormalities such as blisters. From the above results,
It was confirmed that even when using metanitrobenzenesulfonic acid, a stripper having the same performance as the stripper using sodium metanitrobenzenesulfonate described above was obtained.

[Example 24] A stripper (sample 24) having the following composition was prepared using dimethylthiourea instead of thiourea as a component of the stripper (sample 20-7) of Example 20.

Composition of stripping solution (sample 24) 70% methanesulfonic acid: 220 mL / L sodium metanitrobenzenesulfonate: 50 g / L Dimethylthiourea: 30 g / L Ion-exchanged water: balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-silver alloy layer of μm. Next, using the stripping solution (sample 24), a bath temperature of 40 ° C., a bath load of 0.5 dm ² / L, and a liquid volume of 500 mL
Was prepared, and the sample to be peeled was immersed in the bath to peel off the tin-silver alloy layer. The peeling rate of the tin-silver alloy layer, the dissolution rate of the 42 materials, and the appearance of the 42 materials after the peeling of the tin-silver alloy layer in this peeling treatment were measured and evaluated. As a result, the peeling rate of the tin-silver alloy layer was sufficiently high at 7.06 μm / min, and the dissolution rate of the 42 materials was 0.01 μm / min or less, which was good. Also, 42 after peeling off the tin-silver alloy layer.
The surface condition of the material was good without discoloration or smut occurrence.

Next, after the tin-silver alloy layer was peeled off, 42 materials were subjected to alkaline electrolytic degreasing, and a tin-silver alloy layer having a thickness of 10 μm was formed under the same conditions as described above.
Heat treatment was performed at 150C for 15 hours. The appearance of the tin-silver alloy layer formed by re-plating after peeling was good without nodules, and the appearance of the tin-silver alloy layer after heat treatment was good without any abnormalities such as blisters. From the above results,
It was confirmed that a stripper having the same performance as the stripper using thiourea was obtained when dimethylthiourea was used.

[Example 25] First, a stripping solution (sample 25) having the same composition as the stripping solution of Example 18 (sample 18-5) and having the following composition:
Was prepared.

Composition of stripping solution (sample 25): 70% methanesulfonic acid: 200 mL / L sodium metanitrobenzenesulfonate: 50 g / L thiourea: 30 g / L 67.5% nitric acid: 20 mL / L Exchange water… balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. and SUS3 manufactured by Nippon Metal Industry Co., Ltd.
16, a nickel material and an iron material were prepared, and a tin-silver alloy layer having a thickness of 10 μm was formed on these materials to prepare a sample to be peeled. Next, a processing bath having a bath temperature of 40 ° C., a bath load of 0.5 dm ² / L, and a liquid volume of 500 mL was prepared using the above-mentioned stripping solution (sample 25), and each sample to be stripped was immersed in the bath. Then, the tin-silver alloy layer was peeled off. The peeling rate of the tin-silver alloy layer, the dissolution rate of the material, and the appearance of the material after peeling the tin-silver alloy layer in this peeling treatment were measured and evaluated.

After peeling off the tin-silver alloy layer, the material was subjected to alkaline electrolytic degreasing, and then a tin-silver alloy layer having a thickness of 10 μm was formed under the same conditions as described above. , And the appearance of the tin-silver alloy layer after further heat treatment at 170 ° C. for 15 hours was evaluated.
The results are shown in FIG.

[0183]

[Table 14]

As shown in Table 14, the stripping solution of the present invention (sample 25) has a tin-silver alloy layer peeling rate of 3.53 μm with respect to the sample to be stripped whose material is nickel or an iron-nickel alloy. / Min or more, and the dissolution rate of the material was sufficiently small and good. The surface state of the material after peeling the tin-silver alloy layer was good without discoloration or occurrence of smut. Furthermore, the appearance of the tin-silver alloy layer formed by re-plating was good without nodules, and the appearance of the tin-silver alloy layer after the heat treatment was good without any abnormalities such as blisters. In the sample to be peeled whose material is SUS316, the surface state after peeling the tin-silver alloy layer shows some surface roughness, but there is no problem in replating after peeling and heat treatment. It is judged to be a practical level.

However, the dissolution rate of the iron material was as large as 2.91 μm / min with respect to the sample to be peeled made of the iron material.
Nodules were observed in the tin-silver alloy layer formed by re-plating after peeling, and the heat treatment gave blisters in the tin-silver alloy layer.

[Example 26] First, a stripper (sample 26) having the same composition as the stripper of Example 18 (sample 18-6) and having the following composition:
Was prepared.

Composition of stripping solution (sample 26) 70% methanesulfonic acid 250 mL / L sodium metanitrobenzenesulfonate 50 g / L thiourea 30 g / L 67.5% nitric acid 20 mL / L Exchange water… balance

Next, as an iron-nickel alloy, 42 materials manufactured by Sumitomo Special Metals Co., Ltd. were used.
A sample to be peeled was prepared by forming a tin-copper alloy layer having a thickness of μm. Using the above stripper (sample 26), bath temperature 40
A treatment bath having a bath load of 0.5 dm ² / L and a liquid volume of 500 mL was prepared, and the sample to be peeled was immersed in the bath.
The copper alloy layer was peeled off. Tin in this stripping process
The copper alloy layer peeling speed, the 42 material dissolution speed, and the appearance of the 42 materials after the tin-copper alloy layer peeling were measured and evaluated. As a result, the peeling rate of the tin-copper alloy layer was sufficiently high at 4.00 μm / min, and the dissolution rate of the 42 materials was 0.01 μm / min or less, which was good. Moreover, the surface state of the 42 materials after the peeling of the tin-copper alloy layer was good without discoloration or smut generation.

Next, after the tin-copper alloy layer was peeled off, the 42 material was subjected to alkaline electrolytic degreasing, and then a 10 μm-thick tin-copper alloy layer was formed under the same conditions as described above.
Heat treatment was performed at 150C for 15 hours. The appearance of the tin-copper alloy layer formed by replating after peeling was good without nodules, and the appearance of the tin-copper alloy layer after heat treatment was good without any abnormality such as blisters. From the above results,
As in the case of the tin-silver alloy layer, it was confirmed that the tin-copper alloy layer also had excellent peeling performance.

[0190]

As described above in detail, according to the present invention, a lead-free tin alloy layer provided on nickel or an iron-nickel alloy or nickel (iron-nickel alloy) existing thereunder
The tin alloy layer can be reliably peeled off, and the dissolution of nickel or iron-nickel alloy can be extremely low (for example, 0.01 μm / min or less) in this peeling; The surface of the iron-nickel alloy becomes flat, and even if the lead-free tin alloy is plated again, the adhesion with nickel or the iron-nickel alloy is good, and a good adhesion state is maintained even after heat treatment. The effect is achieved.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mikio Shimada 2-3-1 Yoshino-cho, Omiya-shi, Saitama F-term in the Research Department, Meltex Co., Ltd. 4K057 WA04 WB01 WB15 WE11 WE17 WG03 WM03

Claims (7)

[Claims] 1. A stripping solution for stripping a tin-copper alloy which is a lead-free tin alloy, wherein at least alkanesulfonic acid is 35 to 420 mL / L.
Containing (meth) nitrobenzenesulfonic acid or a salt thereof in the range of 10 to 300 g / L,
Further, for removing lead-free tin alloys from nickel or iron-nickel alloys, containing at least one member selected from the group consisting of thioureas, alkylthioureas and aromatic thioureas in a solubility range of 5 g / L or more. Stripper. 2. An alkanesulfonic acid containing 70% methanesulfonic acid in the range of 50 to 600 mL / L and sodium metanitrobenzenesulfonate in an amount of 10 to 60 mL / L.
The stripping solution for stripping a lead-free tin alloy on nickel or an iron-nickel alloy according to claim 1, wherein the stripping solution contains 300 g / L and thiourea in a solubility range of 5 g / L or more. 3. A stripper for stripping a tin-bismuth alloy which is a lead-free tin alloy, wherein at least alkanesulfonic acid is 35 to 420 mL / L.
Containing (meth) nitrobenzenesulfonic acid or a salt thereof in a range of 10 to 250 g / L,
One of the group consisting of benzotriazole, benzimidazole, imidazole and derivatives thereof containing a halogen ion in a solubility range of 0.09 mol / L or more;
A stripper for stripping lead-free tin alloys on nickel or iron-nickel alloys, comprising at least 2 g / L of seeds in a solubility range. 4. The method according to claim 1, wherein 70% methanesulfonic acid is added in an amount of 50 to 600.
mL / L, sodium metanitrobenzenesulfonate in the range of 10-250 g / L,
4. A lead-free nickel or iron-nickel alloy according to claim 3, wherein chloride ions are contained in a solubility range of 0.09 mol / L or more and benzotriazole is contained in a solubility range of 2 g / L or more. Stripping solution for tin alloy stripping. 5. The stripping solution for stripping a lead-free tin alloy on nickel or iron-nickel alloy according to claim 4, wherein benzotriazole is contained in the range of 2 to 50 g / L. 6. A stripper for stripping tin-silver alloy and tin-copper alloy which are lead-free tin alloys, wherein at least alkanesulfonic acid is 35 to 350 mL / L.
In the range of 5 to 250 g / L of (meth) nitrobenzenesulfonic acid or a salt thereof, and one or more of thiourea, alkylthiourea and aromatic thiourea. Contains at least 20 g / L in the solubility range, and contains 0.68 to 40.5 mL / L of nitric acid.
A stripper for stripping lead-free tin alloys on nickel or iron-nickel alloys, characterized in that it is contained in the range of 7. A 50% to 500% methanesulfonic acid.
mL / L, sodium metanitrobenzenesulfonate in a range of 5-250 g / L, thiourea in a solubility range of 20 g / L or more,
The stripping solution for stripping a lead-free tin alloy on nickel or an iron-nickel alloy according to claim 6, wherein the stripping solution contains 7.5% nitric acid in a range of 1 to 60 mL / L.