JP2559935B2 - Method and apparatus for tin or tin-lead alloy electroplating using insoluble anode - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to a tin or tin-lead alloy electroplating process using an insoluble anode and an apparatus for carrying out the process.

[0002]

2. Description of the Related Art Usually, when tin or tin-lead alloy electroplating is carried out, a cathode to be plated and a positive electrode of a soluble anode such as metal tin or a metal tin-lead alloy are used. The metal is replenished in the plating solution by dissolution from the.

In recent years, tin or tin-lead alloy electroplating has undergone technological progress such as speeding up of plating from the viewpoint of improving productivity. Along with this, an anode in electroplating and a cathode which is the counter electrode thereof are formed. The distance between the poles and is becoming shorter. Therefore, the above-mentioned soluble anode cannot change the shape of the electrode plate, and instead of this, an insoluble anode such as an electrode in which platinum is applied to titanium, a carbon electrode, or a ferrite electrode such as MO.Fe ₂ O ₃ is used. The use is increasing. The supply of tin and lead ions into the plating solution is based on frequent analysis, and is performed with a neutral tin compound such as tin oxide.

However, the problem when using an insoluble anode is the method of replenishing the metal. In such a case, the metal replenishment is performed by neutral tin compounds such as tin oxide, for example, stannous oxide (SnO), which is an equiaxed black crystal, has less influence on the plating film than other tin compounds. It is used because of its good solubility in the plating solution and its easy handling. However, in the case of supplying the metal with stannous oxide, there are the following problems. (1) The price of stannous oxide is high, which causes an increase in plating cost using this as a tin ion source. (2) When stannous oxide is stored in air for a long period of time, stannous oxide (SnO ₂ ) is likely to be generated due to the oxidation reaction, which causes the generation of sludge in the plating solution. (3) The inclusion of impurities contained in stannous oxide in the plating solution may adversely affect the plating.

For these reasons, there is a need for a method of metal replenishment using a soluble anode which is inexpensive and easy to operate, taking advantage of the advantages of the insoluble anode. This method is disclosed in JP-A-2-7008.
7, an anion exchange membrane is used and a solution containing anions constituting a metal compound is placed in the cathode chamber of the metal replenishing tank to provide electric conductivity. However, in this method, anions move through the anion exchange membrane to the anode chamber by electrodialysis, and the concentration of anions in the plating solution gradually increases. When the concentration of anions in the plating solution exceeds the normal usage concentration, adverse effects such as a decrease in current efficiency will begin to occur. Further, the movement of the anions in the cathode chamber to the anode chamber gradually reduces the concentration of anions in the cathode chamber, making it difficult to maintain the electrical conductivity.

The present inventors have previously used tin or tin-lead alloy electroplating, especially alkanesulfonic acid, using an insoluble anode.
Regarding a plating solution containing at least one organic sulfonic acid selected from alkanol sulfonic acids and aromatic sulfonic acids and having a divalent tin salt of these organic sulfonic acids or a divalent tin salt and a lead salt as a basic component Instead of replenishing with tin oxide, use an anion exchange membrane and a diffusion dialysis membrane in combination with tin or tin-
We have developed a method to replenish tin or lead ions by melting lead alloys.

That is, a metal replenishment tank is prepared separately from the plating tank, a metal tin or metal tin-lead alloy anode and a cathode serving as its counter electrode are installed therein, and a voltage is applied between the electrodes to remove tin or lead. Dissolves. However, if it is left as it is, tin or a tin-lead alloy will be deposited on the counter electrode. Therefore, the metal replenishment tank is divided into an anode chamber and a cathode chamber by an anion exchange membrane, metal tin or a metal tin-lead alloy is used as an anode in the anode chamber, and a cathode serving as the counter electrode is installed in the cathode chamber to cause electrolysis. Due to the anion exchange membrane, the dissolved tin ions or lead ions do not move into the cathode chamber but accumulate in the anode chamber. By circulating the plating tank and the anode chamber of the metal supply tank with a pump or other means, tin or lead of the plating solution in the plating tank can be supplied. In this case, a solution having the same composition as the plating solution in the plating tank is placed in the anode chamber of the metal replenishing tank, but metal is not deposited on the cathode in the cathode chamber and electric conductivity is provided. It is necessary to put a liquid containing only organic sulfonic acid in.

However, when electrolysis is carried out for the purpose of replenishing metal using this method, migration of cations such as tin ions or lead ions to the cathode chamber does not occur due to the anion exchange membrane in the metal replenishment tank, but In addition, the phenomenon that anions, organic sulfonate ions, move from the cathode chamber to the anode chamber by electrodialysis occurs.

As a result of further research to solve such problems, the present inventors have found that by installing a diffusion dialysis membrane in the metal replenishment tank, the inside of the metal replenishment tank can be
We focused on anion exchange membrane / anode chamber / diffusion dialysis membrane / diffusion dialysis chamber, and put a solution containing only organic sulfonic acid as a diffusion liquid in the diffusion dialysis chamber for electrolysis. Then, the concentration difference of the organic sulfonate ion between the diffusion dialysis chamber and the anode chamber containing the plating solution having the increased organic sulfonate ion concentration serves as a driving force, and the organic sulfonate ion in the plating solution is By moving the diffusion dialysis chamber to the diffusion dialysis chamber and circulating the diffusion dialysis chamber and the cathode chamber of the metal supply tank, the organic sulfonate ion can be supplied to the cathode chamber. It has been found that the ion concentration can be kept constant at all times, facilitating management.

[0010]

Thus, the present invention provides an insoluble anode in a bath containing an organic sulfonic acid and a divalent tin salt or a plating solution containing a divalent tin salt and a lead salt as basic components. And a method of forming a tin or tin-lead alloy plating film on the surface of the object to be plated by installing a cathode, which is the opposite electrode, as the object to be plated, and applying a voltage between the electrodes. Chamber / anion exchange membrane / anode chamber / diffusion dialysis membrane / diffusion dialysis room
A solution containing only organic sulfonic acid is placed in the cathode chamber and the diffusion dialysis chamber, the plating solution is placed in the anode chamber, and a metal tin or metal tin-lead anode is placed in the anode chamber and its counter electrode is placed in the cathode chamber. Characterized in that a voltage is applied between the electrodes to dissolve tin or a tin-lead anode, tin or lead ions are replenished to the plating bath, and an organic sulfonic acid recovered in a diffusion dialysis chamber is supplied to the cathode chamber. The present invention provides a tin or tin-lead alloy electroplating method.

In the above method, the anion exchange membrane and the ion exchange membrane for diffusion dialysis were provided in one tank, that is, the metal replenishment tank, but they can also be installed in another tank.
Thus, the present invention also provides a method for carrying out the method, which is provided outside the plating tank with a metal supply tank equipped with an anion exchange membrane and an organic sulfonic acid recovery tank equipped with an ion exchange membrane for diffusion dialysis.

The present invention further provides an apparatus used to carry out these methods.

The method and apparatus of the present invention will now be described in detail with reference to the drawings.

In the present invention, a plating solution containing an organic sulfonic acid and a divalent tin salt thereof or a divalent tin salt and a lead salt as basic components is used. As the organic sulfonic acid, at least one of alkane sulfonic acid, alkanol sulfonic acid, and aromatic sulfonic acid is used as described above. Examples of the alkanesulfonic acid include methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, 2-propanesulfonic acid, butanesulfonic acid, 2-butanesulfonic acid, pentanesulfonic acid,
Hexanesulfonic acid or the like is used. Of these, methanesulfonic acid is preferably used.

As the alkanol sulfonic acid, 2
-Hydroxyethyl-1-sulfonic acid, 2-hydroxypropyl-1-sulfonic acid, 3-hydroxypropyl-
Examples thereof include 1-sulfonic acid, 2-hydroxybutyl-1-sulfonic acid, 4-hydroxypentyl-1-sulfonic acid and 2-hydroxyhexyl-1-sulfonic acid.

Further, as the aromatic sulfonic acid, benzenesulfonic acid, 4-hydroxybenzenesulfonic acid (P-
Phenol sulfonic acid), 4-carboxybenzene sulfonic acid and the like are exemplified. In addition to these, aromatic disulfonic acids such as 2,5-dihydroxy-1,4-benzenedisulfonic acid and 4,5-dihydroxy-1,3-benzenedisulfonic acid can be exemplified.

Next, as the metal salt, a divalent tin salt of organic sulfonic acid and a lead salt are used. The same organic sulfonic acid is used for the tin salt and the lead salt of the organic sulfonic acid and the organic sulfonic acid as the metal salt.

Addition of organic sulfonic acid is effective for preventing the precipitation of the above metal salts, increasing the thickness of the deposited film, and preventing uneven deposition. The amount added is usually in the range of 5 to 300 g / l, of which the range of 50 to 200 g / l is preferred. On the other hand, the addition amount of tin salt and lead salt of organic sulfonic acid is usually in the range of 5 to 200 g / l, of which 30 to 100
A range of g / l is preferred. In the present invention, Sn60%,
A tin-lead alloy coating having a Pb of 40% or close thereto is desirable, so the tin salt and the lead salt of organic sulfonic acid are added in a corresponding ratio to each other. However, the present invention is also effective when a tin-lead alloy coating film having another ratio is desired if necessary, and in that case, the tin salt and the lead salt are used in the corresponding quantitative ratio.

Various additives such as a surfactant and an antioxidant can be added in addition to the divalent tin salt and the lead salt of the organic sulfonic acid and the organic sulfonic acid as the metal salt.

Now, FIG. 1 schematically shows an embodiment of the method and apparatus according to the present invention. This tin or tin-lead alloy electroplating apparatus is composed of a plating tank 1 and a tank 2 having both metal supply and organic sulfonic acid recovery. The plating bath 1 contains the plating solution 3 as described above, and the insoluble anode 4 in the plating solution 3 and the object to be plated 5 are installed on the cathode serving as the counter electrode. Insoluble anode 4
The object to be plated 5 of the cathode is electrically connected by a DC power supply 6. By applying a voltage between these electrodes, tin or tin-lead alloy is deposited on the object to be plated 5 by the reaction of Sn ²⁺ + 2e ⁻ → Sn or Pb ²⁺ + 2e ⁻ → Pb, and the insoluble anode is also formed. In No. 4, oxygen gas is generated by the reaction of H ₂ O + 2 (R-SO ₃ ⁻ ) → 1/2 (O ₂ ) ↑ + 2 (R—SO ₃ H) + 2e ⁻ (R: alkyl group).

The tank 2 is an anion exchange membrane 7 and a diffusion dialysis membrane 1.
4 is divided into cathode chamber 8 / anion exchange membrane 7 / anode chamber 9 / diffusion dialysis membrane 14 / diffusion dialysis chamber 15. A liquid containing only organic sulfonic acid is placed in the cathode chamber 8 and the cathode 10 is placed in the liquid.
Is installed. Further, the anode chamber 9 has a plating tank 1 and pipes 12, 1.
A plating solution 3 is circulated by means of 3 and metal tin or a metal tin-lead alloy 11 is installed as an anode in this plating solution. The cathode 10 and the metal tin or the metal tin-lead alloy 11 are electrically connected by the DC power supply 6, and by applying a voltage between the electrodes, the metal tin or the metal tin-lead alloy 11 as the anode is , Sn → Sn ²⁺ + 2e ⁻ or Pb → Pb ²⁺ + 2e ⁻ , tin or lead is dissolved as metal ions. Usually, tin or a tin-lead alloy is deposited on the cathode 10 which is the opposite electrode, but since the anion exchange membrane 7 separates the electrodes, a metal ion (Sn ²⁺⁾ which is a cation, Sn ⁴⁺ , Pb ²⁺ ) cannot move to the cathode chamber 8 and accumulate in the anode chamber 9. Since the plating tank 1 and the anode chamber 9 are circulated through the pipes 12 and 13, the plating tank 1
The tin ions or lead ions consumed by the electroplating are replenished from the anode chamber 9. Also, the cathode 1 of the cathode chamber 8
At 0, hydrogen gas is generated by the reaction of 2H ⁺ + 2e ⁻ → H ₂ ↑.

However, in this method, the cathode chamber 8 is electrolyzed.
Since the organic sulfonate ion, which is the anion of, passes through the anion exchange membrane 7 and moves to the anode chamber 9, the organic sulfonate ion whose concentration is increased by this movement is recovered,
It is necessary to supply this again to the cathode chamber 8.

The diffusion dialysis chamber 15 in the tank 2 is previously filled with a liquid containing only organic sulfonic acid as a diffusion liquid. Then, the diffusion dialysis chamber 15 and the anode chamber 9 containing the plating solution whose organic sulfonate ion concentration has been increased by electrodialysis from the cathode chamber 8
There is a difference in the concentration of organic sulfonic acid ions between them, and this acts as a driving force, and the organic sulfonic acid moves to the diffusion dialysis chamber 15 by diffusion dialysis. Since the plating solution 3 is circulated through the plating tank 1 and the pipes 12 and 13 in the anode chamber 9 of the tank 2, the organic sulfonate ion concentration in the plating solution 3 can be controlled to be constant. Since the cathode chamber 8 and the diffusion dialysis chamber 15 of the tank 2 are circulated by the pipes 16 and 17,
The organic sulfonate ion concentration in the cathode chamber 8 can be controlled to be constant.

As means for circulating the plating solution 3 in the pipes 12 and 13 or circulating the organic sulfonic acid solution in the pipes 16 and 17, an overflow, a pump or the like is used, but the means is not particularly limited. I'm good.

The plating bath and the metal replenishing bath form an electric circuit in series by one DC power source, but this is not particularly limited, and even if the DC power source is separately taken and each electric circuit is formed. good.

The anion exchange membrane is usually commercially available, and preferably has acid resistance, heat resistance and organic contamination resistance, for example, Neoceptor ACM and Neoceptor AMH.
(Product name of Tokuyama Soda Co., Ltd.) is used.

The diffusion dialysis membrane is a commercially available ion exchange membrane, and preferably has acid resistance, heat resistance, and organic contamination resistance, such as Neoceptor AFX (trade name of Tokuyama Soda Co., Ltd.).

In the example shown in FIG. 1, the anion exchange membrane and the diffusion dialysis membrane are installed in one tank. However, these are not particularly limited, and metal replenishment and organic sulfonic acid recovery may be performed in separate tanks.

FIG. 2 shows an example in which metal replenishment and organic sulfonic acid recovery are performed in separate tanks as described above, and a metal replenishment tank 18 having an anion exchange membrane 7 outside the plating tank 1 is provided.
And a diffusion dialysis tank (organic sulfonic acid recovery tank) 19 equipped with an anion exchange membrane 14 for diffusion dialysis. Metal supply tank 1
The ion exchange membrane 7 divides the cathode chamber 8 into a cathode chamber 8 having a cathode 10 and an anode chamber 9 having an anode 11. As the anode 11, metallic tin or metallic tin-lead alloy is used. On the other hand, in the diffusion dialysis tank 19, the diffusion dialysis membrane 15 separates the diffusion dialysis chamber 15 and the plating solution circulation chamber 20.

The anode chamber 9 of the plating tank 1 and the metal replenishment tank 18 and the plating solution circulation chamber 20 of the diffusion dialysis tank 19 have pipes 12 and 21.
And 22, the plating solution 3 is circulated. In the cathode chamber 8 of the metal replenishing tank 18 and the diffusion dialysis chamber 15 of the diffusion dialysis tank 19, the organic sulfonic acid is circulated through the pipes 16 and 17.

The plating solution 3 as described above is placed in the anode chambers of the plating tank 1 and the metal supply tank 18, and only the organic sulfonic acid solution is placed in the cathode chamber of the metal supply tank 18, and metal tin or metal tin is used as the anode. -When a lead alloy is used and its counter electrode such as stainless steel is installed on the cathode and then a voltage is applied between the electrodes, the anode of the metal replenishment tank dissolves to produce tin ions or lead ions, which are plated by the pipe 12. It is sent to the tank 1 and replenished in the plating solution.

On the other hand, the organic sulfonate ion in the cathode chamber 8 of the metal replenishment tank 18 moves to the anode chamber 9 through the anion exchange membrane 7 and passes through the pipe 12, the plating tank 1 and the pipe 21 to the circulation chamber 20 of the diffusion dialysis chamber 19. Further, it is recovered in the diffusion dialysis chamber 15 via the diffusion dialysis membrane 14 and supplied again to the cathode chamber 8.

Thus, in the tin or tin-lead alloy electroplating method according to the present invention, the replenishment of tin ion or lead ion to the plating solution having a reduced metal concentration is performed by using a metal tin or lead ion in a bath different from the plating bath. A voltage is applied between the metal-tin-lead alloy anode and its opposite cathode to dissolve tin or lead, and the recovery of organic sulfonate ions from the plating solution is also achieved by diffusion using a tank equipped with a diffusion dialysis membrane. It can be performed by dialysis. Therefore, it becomes easy to control the metal concentration and the organic sulfonate ion concentration, and the plating can be continuously performed without exchanging the plating solution or separately supplying the metal. Again 4
The generation of valent tin ions is small, and since electroplating can be performed with high efficiency, the cost can be kept low.

[0034]

EXAMPLES Specific examples will be shown below. [Example 1] Using the apparatus shown in Fig. 1, electrolytic tin plating was performed under the following conditions. (1) Composition of tin plating solution Stannous ion (added as stannous methanesulfonic acid) 60 g / L methanesulfonic acid 120 g / L additive Appropriate amount (polyoxyethylene glycol based surfactant is used as the above additive) (2) It contains hydroxybenzene, which has an antioxidant effect.) (2) Tin plating conditions Current: 10 A Cathode current density: 3 A / dm ² Anode: Insoluble anode with platinum on titanium Cathode: Copper plate (3) Metal tin anode dissolution conditions Current: 10 A Anode current density: 3 A / dm ² Anode: Metal tin anode Cathode: Stainless steel plate (SUS316) The tin plating solution of the above composition is placed in the anode chamber 9 of the plating tank 1 and tank 2 in FIG. It is circulated by 12 and 13. In addition, the cathode chamber 8 and the diffusion dialysis chamber 15 of the tank 2 have 150
A methanesulfonic acid solution of g / L is put therein and is circulated through pipes 16 and 17. The liquid temperature was kept constant at 30 ° C., and the electrolysis time was 5 hours.

The anion exchange membrane 7 is Neoceptor AMH (trade name of Tokuyama Soda Co., Ltd., effective area: 4 dm ² ), and the diffusion dialysis membrane is an ion exchange membrane, Neocepta AFX (trade name of Tokuyama Soda Co., Ltd., effective area: 5 dm). ² ) was used, but it is not limited to these.

The cathode 10 of the tank 2 is a stainless steel plate (SU
Although S316) is used, it is not limited to this.

The variation of the composition of the plating solution of Example 1 is shown in Table 1. Example 2 Next, tin-lead alloy electroplating was performed with the following composition using the apparatus shown in FIG.

Tin-lead alloy plating solution composition (90% tin-10% lead) Stannous ion (added as stannous methanesulfonate) 60 g / L Lead ion (added as lead methanesulfonate) 6 g / L methane Sulfonic acid 150 g / L Additive Amount (The above additives include a polyoxyethylene glycol-based surfactant and hydroxybenzene having an antioxidant effect.) The anode 11 in the tank 2 is a metal tin-lead alloy anode. Electrolysis was carried out for 5 hours under the same conditions as in Example 1 except for the above.

Table 2 shows the variation of the composition of the plating solution of Example 2. Example 3 Next, using the apparatus shown in FIG. 1, tin-lead alloy electroplating was performed with the following composition.

Tin-lead alloy plating solution composition (90% tin-10% lead) stannous ion (added as stannous P-phenol sulfonate) 60 g / L lead ion (added as lead P-phenol sulfonate) 6 g / L P-phenol sulfonic acid 180 g / L additive Appropriate amount (The above additives include a polyoxyethylene glycol-based surfactant and hydroxybenzene having an antioxidant effect.) The anode 12 in the tank 2 is Using a metal tin-lead alloy anode,
Others were electrolyzed under the same conditions as in Example 1 for 5 hours.

Table 3 shows the variation in the composition of the plating solution of Example 3. [Example 4] Next, using the apparatus shown in Fig. 2, tin-lead alloy electroplating was performed with the following composition.

Tin-lead alloy plating solution composition (90% tin-10% lead) Stannous ion (added as stannous methanesulfonate) 60 g / L Lead ion (added as lead methanesulfonate) 6 g / L methane Sulfonic acid 150 g / L Additive amount (The above additives include a polyoxyethylene glycol-based surfactant and hydroxybenzene having an antioxidant effect.) As is clear from FIG. 2, the plating tank 1 and metal supplementation Tank 18
The anode chamber 9 and the chamber 20 of the diffusion dialysis tank 19 are connected to the pipes 12, 2
1 and 22 circulate the tin-lead alloy plating solution having the above composition. Further, the cathode chamber 8 of the metal replenishment tank 18 and the diffusion dialysis chamber 15 of the organic sulfonic acid recovery tank 19 are connected to the pipes 16 and 17 respectively.
The organic sulfonic acid solution is circulated. Anode 11
Was a metal tin-lead alloy anode, and other conditions were the same as in Example 1, and electrolysis was performed for 5 hours. Table 4 shows the variation in the composition of the plating solution of Example 4.

_{Table 1} Composition of plating solution (g / L) ^{Initial composition Post-electrolytic composition Stannous ion 60 61 Methanesulfonic acid 120 118}

_{Table 2} Composition of plating solution (g / L) ^{Initial composition Post-electrolysis composition Stannous ion 60 62 Lead ion 6 6 Methanesulfonic acid 150 147} _{Table 3} Composition of plating solution (g / L) ^{Initial composition Post-electrolysis composition Stannous ion 60 61 Lead ion 6 6 Phenolsulfonic acid 180 178} _{Table 4} Composition of plating solution (g / L) ^{Initial composition After electrolysis Stannous ion 60 62 Lead ion 6 6 Methanesulfonic acid 150 146}

[0045]

As described above, the tin and tin-lead alloy electroplating method according to the present invention can easily and inexpensively supply insufficient metal without affecting the composition of the plating solution. I can.

The tin and tin-lead alloy electroplating apparatus according to the present invention can be continuously and easily controlled as a whole when the method of the present invention as described above is carried out.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an apparatus of the present invention.

FIG. 2 is a schematic view showing another example of the device of the present invention.

[Explanation of symbols]

 1 Plating Tank 2 Metal Supply and Organic Sulfonic Acid Recovery Tank 3 Plating Solution 4 Insoluble Anode 5 Plated Object 6 DC Power Supply 7 Anion Exchange Membrane 8 Cathode Chamber 9 Anode Chamber 10 Cathode 11 Metal Tin or Metal Tin-Lead Alloy Anode 14 Diffusion Dialysis membrane 15 Diffusion dialysis room 18 Metal supply tank 19 Organic sulfonic acid recovery tank 12, 13, 16, 17, 21, 22 Piping

Claims (6)

(57) [Claims] 1. An organic sulfonic acid and its divalent tin salt or 2
Surface of the object to be plated by placing an insoluble anode and a cathode, which is its counter electrode, as an object to be plated in a bath containing a plating solution containing a basic tin salt and a lead salt, and applying a voltage between the electrodes. In the method for forming a tin or tin-lead alloy plating film on a cathode, a metal replenishment tank having a cathode chamber / anion exchange membrane / anode chamber / diffusion dialysis membrane / diffusion dialysis chamber is provided separately from the plating bath, A solution containing only organic sulfonic acid is placed in the chamber and the diffusion dialysis chamber, the plating solution is placed in the anode chamber, and a metal tin or metal tin-lead anode is installed in the anode chamber and its counter electrode is installed in the cathode chamber, A voltage is applied between the electrodes to dissolve the tin or tin-lead anode, the tin or lead ions are replenished to the plating tank, and the organic sulfonic acid recovered in the diffusion dialysis chamber is supplied to the cathode chamber. Tin or tin-lead alloy electroplating method 2. In the metal replenishment tank, the organic sulfonate ions that have moved from the cathode chamber through the anion exchange membrane to the anode chamber are recovered in the diffusion dialysis chamber through the diffusion dialysis membrane and supplied again to the cathode chamber. The method according to claim 1, characterized in that 3. A plating tank having an insoluble anode and a cathode serving as an opposite electrode to be plated, and a cathode chamber / anion exchange membrane /
An anode chamber / diffusion dialysis membrane / diffusion dialysis chamber are provided in this order, a metal tin or metal tin-lead alloy anode is provided in the anode chamber, a metal replenishing tank is provided with a counter electrode in the cathode chamber, and an anode chamber of the metal replenishing tank. It has a device that circulates a plating solution between the metal plating tank and a plating tank, and a device that circulates an organic sulfonic acid solution between the cathode chamber and the diffusion dialysis chamber of the metal supply tank, and continuously supplies metal and sulfonic acid. A tin or tin-lead alloy electroplating apparatus characterized by the above. 4. An insoluble anode and its counter electrode are installed as an object to be plated in a bath containing a plating solution containing organic sulfonic acid and its divalent tin salt or divalent tin salt and lead salt as basic components. To the surface of the object to be plated by applying tin or tin-
In the method of forming a lead alloy plating film, a metal replenishment tank separated into an anode chamber and a cathode chamber by an anion exchange membrane separately from the plating tank and a diffusion dialysis membrane separately from the plating tank and the metal replenishment tank. Separated organic sulfonic acid recovery tanks are installed in the liquid circulation chamber and the diffusion dialysis chamber, a solution of organic sulfonic acid only is put in the cathode chamber and the diffusion dialysis chamber, and the plating solution is put in the anode chamber, and the metal supply is made up. A metal tin or metal tin-lead anode plate is installed in the anode chamber of the tank, and a counter electrode is installed in the cathode chamber to apply a voltage between the electrodes to dissolve the tin or tin-lead anode and supply tin or lead ions to the plating tank. And the organic sulfonic acid obtained in the organic sulfonic acid recovery tank is supplied to the cathode chamber of the metal replenishing tank. 5. In the metal replenishment tank, the organic sulfonate ions that have moved from the cathode chamber to the anode chamber through the anion exchange membrane are passed through the plating tank and from the plating solution circulation chamber of the organic sulfonic acid recovery tank through diffusion dialysis membrane to perform diffusion dialysis 5. The tin or tin-lead alloy electroplating method according to claim 4, wherein the tin or the tin-lead alloy electroplating is carried out by recovering in a chamber and supplying again to the cathode chamber. 6. A plating tank having an insoluble anode and a cathode which is an opposite electrode to the object to be plated, a metal supply tank divided into an anode chamber and a cathode chamber by an anion exchange membrane, and a plating solution circulation chamber by a diffusion dialysis membrane. And a device for circulating a plating solution between the plating tank and the plating solution circulation chamber of the sulfonic acid recovery tank and the anode chamber of the metal supply tank. The apparatus has a device for circulating an organic sulfonic acid between the diffusion dialysis chamber of the organic sulfonic acid recovery tank and the cathode chamber of the metal supply tank, and is configured to continuously supply the metal and the organic sulfonic acid. To do
Tin or tin-lead alloy electroplating equipment.