Peeling liquid for coating of tin or tin alloy

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a stripping solution for stripping a tin or tin alloy film from a base metal substrate at a high speed.

【0002】

[Conventional technology]

From the viewpoint of recent environmental regulations, there is a strong tendency to not use lead, and the conventional lead-containing solder (tin: lead = 60: 40) is shifting to lead-free solder. The lead-free solder composition is mainly tin: silver, bismuth, copper, zinc, indium, etc., and the tin content is 95% or more, which is significantly different from the conventional lead-containing solder. Therefore, the lead-free solder film cannot be sufficiently peeled off with conventional immersion stripping solutions such as inorganic acid-hydrogen peroxide and hydrogen peroxide-fluoride, and electrolytic stripping solutions such as sulfuric acid-nitrobenzenesulfonic acid. .. It takes a long time to sufficiently peel off. For example, in a solder plating line, since the conduction jig is usually immersed in a plating solution, the jig is also plated.

【0003】

Lead-free solder plating cannot be sufficiently peeled off within the conventional lead-containing solder plating peeling time, so jigs that cannot be removed remain plated, and as a result, the conductivity changes and plating of the object to be plated. There is a problem because the thickness varies. Further, if the peeling time is lengthened to peel off the film plated on the jig, the productivity is lowered, which is also a problem. Therefore, in the field of plating, there is an urgent need for practical application of a treatment liquid capable of peeling a lead-free solder film at a speed equivalent to that of a lead-containing solder film.

【0004】

[Problems to be Solved by the Invention]

An object of the present invention is to provide a stripping liquid for stripping a tin or tin alloy film from a base metal substrate at a high speed.

【0005】

[Means to solve the problem]

As a result of diligent studies, the present inventors have found that tin or a tin alloy film can be peeled off at high speed by adding a peeling accelerator and a hydrogen peroxide stabilizer to a hydrogen peroxide-fluoride system. Reached.

【0006】

That is, the present invention comprises (a) hydrogen peroxide, (b) acidic ammonium fluoride, (c) inorganic acid, (d) amidosulfate or amidosulfate, and (e) a thioamide compound represented by the following formula (1). It relates to a tin or tin alloy film stripping solution which is an aqueous solution containing.

【0007】

[Chemical 2]

<img file="JP2002194574A_D0001.tif" />【0008】

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is an aqueous solution containing the following five types of components. The amount of hydrogen peroxide added to the component (a) is not particularly limited, but is preferably 1 to 30% by weight. If the addition amount is less than 1% by weight, the oxidative effect is insufficient and a sufficient peeling rate cannot be obtained, and if the addition amount exceeds 30% by weight, no further oxidative effect can be obtained, which is economically unfavorable.

【0009】

The amount of the acidic ammonium fluoride added as the component (b) is not particularly limited, but is preferably 1 to 35% by weight. If the addition amount is less than 1% by weight, a sufficient peeling speed cannot be obtained, and if the addition amount exceeds 35% by weight, further improvement in the peeling speed cannot be obtained, which is economically unfavorable.

【0010】

Examples of the inorganic acid of the component (c) include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid and the like, and among them, hydrochloric acid, sulfuric acid and nitric acid are preferable. The amount of the inorganic acid added to the component (c) is not particularly limited, but is preferably 1 to 40% by weight. If the addition amount is less than 1% by weight, a sufficient peeling speed cannot be obtained, and if the addition amount exceeds 40% by weight, further improvement in the peeling speed cannot be obtained, which is economically unfavorable.

【0011】

The amidosulfate or amidosulfate of the component (d) is effective as a peeling rate accelerator. The main ones include amidosulfate, potassium amidosulfate, sodium amidosulfate, calcium amidosulfate, ammonium amidosulfate and the like. Of these, preferred are amidosulfate, potassium amidosulfate and ammonium amidosulfate. The amount of amide sulfuric acid or amide sulfate added as component (d) is not particularly limited, but is preferably 1 to 30% by weight. If the addition amount is less than 1% by weight, a sufficient peeling speed cannot be obtained, and if the addition amount exceeds 30% by weight, further improvement in the peeling speed cannot be obtained, which is economically unfavorable.

【0012】

The thioamide compound of component (e) is effective as a stabilizer for hydrogen peroxide. By adding the amide sulfate or the amide sulfate of the component (d), the peeling rate with respect to the tin or tin alloy film is improved, but on the other hand, the decomposition of hydrogen peroxide occurs and the high peeling rate is maintained. I can't. Therefore, although it has been difficult to put it into practical use until now, it is possible to suppress the decomposition of hydrogen peroxide and maintain a high peeling rate by adding the thioamide compound of the component (e).

【0013】

The main ones are thioformamide, thioacetamide, thiopropionamide, thiobenzamide, thionicotinamide, thioacetanilide, thiobenzanilide, thiourea, 1,3-dimethylthiourea, 1,3-diethyl-2-thiourea. , 1-Phenyl-2-thiourea, 1,3-diphenyl-2-thiourea, thiocarbazide, thiosemicarbazide, 4,4-dimethyl-3-thiosemicarbazide, 2-mercaptoimidazoline, 2-thiouracil, 2-thiohydranthin , 3-thiourazole, 2-thiouramil, 4-thiouramil, thiopental, 2-thiobarbituric acid, thiocyanuric acid, 2-mercaptoquinoline, thiokumazone, thiocumothiazone, thiosaccharin, 2-mercaptobenzimidazole and the like. Of these, preferred are thioacetamide, thiourea, 2-thiouracil and thiocyanic acid, and more preferred are thiourea and thiocyanic acid.

【0014】

The amount of the thioamide compound added as the component (e) is not particularly limited, but is preferably 0.01 to 5% by weight. If the addition amount is less than 0.01% by weight, the effect of hydrogen peroxide as a stabilizer may not be sufficiently obtained, and if the addition amount exceeds 5% by weight, it is economically unfavorable. Only one kind of the thioamide compound of the component (e) may be added, or two or more kinds may be added. Furthermore, it can be used in combination with a generally known hydrogen peroxide stabilizer.

【0015】

The stripping solution of the present invention contains a generally known copper inhibitor such as azoles when the base metal of the tin or tin alloy film is copper or a copper alloy and it is desired to prevent the dissolution of those metals. be able to. The operating temperature of the stripping solution of the present invention is not particularly limited, but is preferably 20 to 60 ° C. The higher the operating temperature, the faster the peeling speed, but if it exceeds 60 ° C, the decomposition of hydrogen peroxide becomes severe, which is not preferable.

【0016】

[Example]

Examples and comparative examples are shown below, and the present invention will be specifically described, but the present invention is not limited to the following examples.

【0017】

Example 1 A sample in which 20 μm of a tin alloy (tin: bismuth = 97: 3) plating film was formed on a 100 × 30 × 0.3 mm SUS304 plate was prepared with 5% by weight of hydrogen peroxide, 15% by weight of acidic ammonium fluoride, and 5 of sulfuric acid. The strip was immersed in a stripping solution containing% by weight, 10% by weight of amidosulfuric acid, and 0.05% by weight of thiocyanuric acid at 35 ° C. for 30 seconds. Table 1 shows the peeling rate of the tin alloy film and the decomposition rate of hydrogen peroxide 24 hours after the peeling.

【0018】

[Number 1]

<img file="JP2002194574A_D0002.tif" />【0019】

Example 2 Instead of using a stripping solution containing 5% by weight of hydrochloric acid, 15% by weight of acidic ammonium fluoride, 5% by weight of sulfuric acid, 10% by weight of amide sulfuric acid, and 0.05% by weight of thiocyanic acid, 10% by weight of hydrochloric acid and acidic foot The procedure was carried out under the same conditions as in Example 1 except that a stripping solution containing 20% by weight of ammonium carbonate, 1% by weight of hydrochloric acid, 20% by weight of potassium amidosulfate and 0.2% by weight of thiourea was used. The results are shown in Table 1.

【0020】

Example 3 A sample in which 20 μm of a tin alloy (tin: silver = 96.5: 3.5) plating film was formed on a 100 × 30 × 0.3 mm SUS304 plate was prepared with 5% by weight of hydrogen peroxide, 15% by weight of acidic ammonium fluoride, and 5 of sulfuric acid. It was immersed in the stripping solution containing% by weight, 10% by weight of amidosulfuric acid, and 0.02% by weight of thiocyanuric acid at 35 ° C. for 30 seconds. The results are shown in Table 1.

【0021】

Example 4 Instead of using a stripping solution containing 5% by weight of hydrogen peroxide, 15% by weight of acidic ammonium fluoride, 5% by weight of sulfuric acid, 10% by weight of amide sulfuric acid, and 0.02% by weight of thiocyanic acid, 10% by weight of hydrogen peroxide and acidic foot The procedure was carried out under the same conditions as in Example 3 except that a stripping solution containing 20% by weight of ammonium carbonate, 20% by weight of nitric acid, 20% by weight of ammonium amidosulfate and 0.05% by weight of 2-thiouracil was used. The results are shown in Table 1.

【0022】

Example 5 A sample in which 20 μm of a tin alloy (tin: lead = 60: 40) plating film was formed on a 100 × 30 × 0.3 mm SUS304 plate was prepared with 5% by weight of hydrogen peroxide, 15% by weight of acidic ammonium fluoride, and 5 of sulfuric acid. It was immersed in the stripping solution containing% by weight, 10% by weight of amidosulfuric acid, and 0.02% by weight of thiocyanuric acid at 35 ° C. for 30 seconds. The results are shown in Table 1.

【0023】

Comparative example 1 Instead of using a stripping solution containing 5% by weight of hydrogen peroxide, 15% by weight of acidic ammonium fluoride, 5% by weight of sulfuric acid, 10% by weight of amide sulfuric acid, and 0.05% by weight of thiocyanic acid, 15% by weight of acidic ammonium fluoride and sulfuric acid The procedure was carried out under the same conditions as in Example 1 except that a stripping solution containing 5% by weight, 10% by weight of amidosulfuric acid and 0.05% by weight of thiocyanuric acid was used. The results are shown in Table 1.

【0024】

Comparative example 2 Instead of using a stripping solution containing 5% by weight of hydrogen peroxide, 15% by weight of acidic ammonium fluoride, 5% by weight of sulfuric acid, 10% by weight of amide sulfuric acid, and 0.05% by weight of thiocyanic acid, 5% by weight of hydrogen peroxide and 5% by weight of sulfuric acid The procedure was carried out under the same conditions as in Example 1 except that a stripping solution containing% by weight, 10% by weight of amidosulfuric acid and 0.05% by weight of thiocyanuric acid was used. The results are shown in Table 1.

【0025】

Comparative example 3 Instead of using a stripping solution containing 5% by weight of hydrogen peroxide, 15% by weight of acidic ammonium fluoride, 5% by weight of sulfuric acid, 10% by weight of amide sulfuric acid, and 0.02% by weight of thiocyanuric acid, 5% by weight of hydrogen peroxide and acidic foot The procedure was carried out under the same conditions as in Example 3 except that a stripping solution containing 15% by weight of hydrogen peroxide, 10% by weight of amidosulfuric acid and 0.02% by weight of thiocyanuric acid was used. The results are shown in Table 1.

【0026】

Comparative example 4 Instead of using a stripping solution containing 5% by weight of hydrogen peroxide, 15% by weight of acidic ammonium fluoride, 5% by weight of sulfuric acid, 10% by weight of amide sulfuric acid, and 0.02% by weight of thiocyanic acid, 5% by weight of hydrogen peroxide and acidic foot The procedure was carried out under the same conditions as in Example 3 except that a stripping solution containing 15% by weight of hydrogen peroxide, 5% by weight of sulfuric acid and 0.02% by weight of thiocyanic acid was used. The results are shown in Table 1.

【0027】

Comparative example 5 Instead of using a stripping solution containing 5% by weight of hydrogen peroxide, 15% by weight of acidic ammonium fluoride, 5% by weight of sulfuric acid, 10% by weight of amide sulfuric acid, and 0.02% by weight of thiocyanic acid, 5% by weight of hydrogen peroxide and acidic foot The procedure was carried out under the same conditions as in Example 3 except that a stripping solution containing 15% by weight of hydrogen peroxide, 5% by weight of sulfuric acid and 10% by weight of amide sulfuric acid was used. The results are shown in Table 1.

【0028】

Comparative example 6 Instead of using a stripping solution containing 5% by weight of hydrogen peroxide, 15% by weight of acidic ammonium fluoride, 5% by weight of sulfuric acid, 10% by weight of amide sulfuric acid, and 0.02% by weight of thiocyanic acid, 5% by weight of hydrogen peroxide and acidic foot The procedure was carried out under the same conditions as in Example 3 except that a stripping solution containing 15% by weight of ammonium carbonate, 5% by weight of sulfuric acid, 10% by weight of amide sulfuric acid and 0.1% by weight of ethylenediamine tetraacetic acid tetrasodium salt was used. The results are shown in Table 1.

【0029】

[table 1]

<img file="JP2002194574A_D0003.tif" />【0030】

[Effect of the invention]

By using the release agent of the present invention, it is possible to release a lead-free solder film at a speed equivalent to that of a lead-containing solder film.