TWI279456B - Regeneration method for a plating solution - Google Patents

Abstract

The invention relates to a method of depositing a layer of metal and to a method of regenerating a solution containing metal ions in a high oxidation state. To regenerate tin ions consumed from a tin plating solution by metal deposition, it has been known in the art to carry the plating solution over metallic tin to cause tin (II) ions to form. However, the amount of tin contained in thus regenerated baths slowly and continuously increases. The solution to this problem is to utilize an electrolytic regeneration cell that is provided with at least one auxiliary cathode and with at least one auxiliary anode. Tin serving for regeneration is electrolytically deposited from the solution onto the at least one auxiliary cathode in the electrolytic regeneration cell. The solution is carried over the tin serving for regeneration in order to reduce formed tin (IV) ions to tin (II) ions.

Description

1279456 A7

1279456 A7 ___ B7 V. INSTRUCTIONS (2—)—— "一- Before the depression of the bonding strength is sufficient, the copper surface needs to be roughened. To achieve this, the surface has so far been surface-oxidized by treatment with so-called black oxide. Of course

However, the oxide layer formed thereby is insufficient to be resistant to acid, so that the inner layer which is cut in the process of drilling the PCB material is layered from the resin of the PCB material to form a layer. This problem is avoided when a tin layer is used to replace the black oxide layer. For production, the tin layer is deposited directly by bonding the copper surface to the circuit traces. In the post-treatment, if necessary, further bonding compounds are applied to the tin layer before the inner layer is pressed together by heat and pressure [for example, a mixture of urea-based stone garden and Ershi Xiyuan cross-linking agent (European Patent 〇 545 216 A2)]. In the second application mentioned, when the metal-free metal regions must be coated with tin, the tin or tin-lead alloy layers can be electrolytically deposited, respectively, in the first and last cases, Tin is not deposited by electrolysis because the copper areas coated by the metal are generally isolated from each other, making it difficult to establish electrical contact. For this reason, the so-called glue bath is used for tin coating. A coating bath of this type is described in U.S. Patent 4,715,894. In addition to the Sn(II) compound, this bath also contains a thiourea compound and a urea compound. According to European Patent 0 545 216 A2, sulphur urea, urea and its derivatives can also be used as a substitute. Further, the solution according to U.S. Patent No. 4,715,894 also contains a binder, a reducing agent and an acid. Therefore, the Sn(n) compound used is, for example, SnS〇4. According to European Patent No. 545 216 A2, the bath comprises an inorganic (mineral) acid Sn(II) compound, for example a compound containing sulfur, phosphorus and halogen acids; or an organic acid compound such as formic acid Sn(n) And acetic acid

Sn (II). According to European patent 〇 545 216 A2, the Sn(II) salt of sulfur-containing acid is -6 - 谏 paper scale applicable to China National Standard (CNS) A4 specification (210 X 4 7 dong) " ----- ! 279456 A7 B7 V. INSTRUCTIONS (: 3 preferred, ie, salts of sulfuric acid or aminosulfonic acid. Further, the bath may also contain an alkali metal stannate such as sodium stannate or potassium stannate. In addition, in the simplest case, 'sulfur urea and urea compounds are unsubstituted derivatives of sulfur-based urea and urea compounds, respectively. According to European Patent 〇 545 216 A2, when tin is deposited, it is wrong with sulfur-based urea. The Cu(I) ions are formed on the copper surface. Simultaneously, the metal tin is deposited by reduction of Sn(II) ions. In this reaction, copper is dissolved and the tin coating is simultaneously formed on the copper surface. European Patent 0 545 216 A2 reports that Cu(I) thiourea complex is enriched in solution. When oxygen from air is brought into solution, Sn(IV) ions are also enriched by oxidation of 3n(II) ions. Contained in solution. However, when the printed circuit board is only immersed in the solution for treatment, Cu(1) thiourea complex and Sn(iv) The concentration of ions does not exceed a fixed concentration value because the bath solution is permanently discharged by the circuit board and diluted with the water being brought in. However, if the bath fluid is sprayed onto the copper surface in the manner of a mouthpiece, relative to the The material flow rate of the bath volume is quite high. In these cases, the concentration of the Cu(1) thiourea complex increases to the extent that it reaches the solubility limit, and the complex precipitates as a deposit. The deposition blocks the nozzle and causes Problems in the movable mechanical parts of the factory. In the coating bath, when the air is brought into the bath solution by a spray to the printed circuit board, the Sn(iv) compound is also passed by the sn (11) Ions are gradually formed by oxidation of oxygen from the air. To reduce these problems, the following clauses are described in the publications mentioned: in order to reduce the concentration of Cu(1)thiourea complex, coating A portion of the bath solution is removed from the processing vessel into another tank where the beans are left to cool, and most of the complex is precipitated and thus separated.

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The solution, which is substantially free of complex, is then sent to a processing vessel. In order to further reduce the Sn(IV) ion concentration in the coating solution, a reservoir for coating a solution containing metal tin is provided. The solution contained in the reservoir is sprayed onto the copper surface, and the Sn(II) ions are reduced according to the reaction equation (1) proposed below, and the metal copper is simultaneously oxidized according to the reaction equation (2) also proposed below to form Cu(1) ions. The complex with thiourea or its derivative thus forms the same 犄' via the oxygen brought to the solution, part of the Sn(n) ion root

The Sn(IV) ion is formed by oxidation according to the reaction equation (3) proposed below. The sprayed solution is then sent to a storage tank. At this point, the Sn(IV) ion reacts with the metal tin to form a double amount of Sn(II) ions according to the reaction equation (4) proposed below. Order

The method of reclaiming tin coated glue bath is described in European Patent 545 545 216 ,, however it has been shown that the concentration of tin contained in the solution is continuously increased. Therefore, the concentration of Sn(II) ions in the solution must be controlled by permanent analysis. This is generally not easy under manufacturing conditions and is often prone to cause large variations in concentration. The result: the deposition of tin becomes uncontrollable. This is unacceptable. A method for overcoming this problem involves automatic monitoring of the concentration of Sn(n) ions and allows or eliminates contact between the coating solution and the tin metal in the reservoir, respectively, when the reference value of the pre-measurement range exceeds or does not reach. This is a very complicated device that requires considerable complexity. It is therefore an object of the present invention to overcome the problems mentioned and to find a method for allowing the copper surface to be coated by gluing without the Sn(II) ion content variation affecting the deposition of tin. The goal is to make it possible without using complicated devices.

1279456 V. Description of the invention (a solution to this purpose is mainly - the coating method of the patent range 1 of 4α - Λ疋 及 及 及 及 及 及 及 及 及 、 、 、 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 It is pointed out in the printed patent circumstance. The coated enamel according to the present invention is used to produce a metal layer, more specifically a tin-containing layer 'and preferably a pure tin layer. The β 玄 method can also be used. Depositing a layer comprising a tin alloy. The following method steps are involved: a. a metallization bath is more specifically a tin coating bath; a metal ion contained in a low oxidizing odor, more particularly a sn(n) ion; b. depositing a metal layer from the metal coating bath onto the work piece; c. providing an electrolytic regeneration battery comprising at least one auxiliary cathode and at least one auxiliary anode; d. in the electrolytic regeneration battery, electrolytic deposition from the metal coating bath as Regenerating the metal to at least one auxiliary cathode, the metal being more specifically metal tin, e. contacting the metal coating bath with the metal for regeneration, and striving to reduce the metal ion contained in the high oxidation state of the metal coating bath More specific; t is a Sn(IV) ion, which is a metal ion in a low oxidation state - more specifically a Sn(II) ion. A regeneration method of the invention is used to regenerate a metal ion containing a high oxidation state. The solution of ^V) ions, in order to reduce the metal ions in the high oxidation state, becomes a metal ion in a low oxidation state, more specifically as (9) ions. This includes the following method steps: a. providing an electrolytic regeneration battery 'containing at least one auxiliary cathode and at least one auxiliary anode; b. electrolytically regenerating the battery from the solution as a regenerated gold

X 297 mm) 1279456 V. Description of the invention (6 belongs to at least one auxiliary cathode; c) Contacting the present solution with the metal as a regenerative metal, and striving to reduce the highly oxidized genus ion is more specific to Sn(IV) ion, a metal ion in a low oxidation state, more specifically a Sn(II) ion. t thereafter a tin-containing layer, a tin coating bath or a tin coating solution, a metal tin, (II) an ion Sn(IV) ion, and a tin electrode or When the tin-containing electrodes are referred to, respectively, the same must be applied and replaced by metal, gold 4 coating bath, metal metal oxide, metal oxide or metal-containing electrode. The method can be used with a reducing agent, and more specifically for the electroless deposition of tin or tin alloys, for the electrolytic deposition of tin and tin alloys, and by the bonding of tin or tin alloys. Method 'This method means that the deposited metal obtains from the substrate metal the desired electrons for reduction to zero oxidation state, the substrate metal is simultaneously oxidized and preferably so dissolved. The method of the invention is more specific Tin-containing layer for coating The surface is applied to a printed circuit board or other circuit carrier. In the method described in European Patent No. 0 545 216, metal tin is added to the coating solution contained in the storage tank to convert % (1 ¥) into Sn(n) ions. In contrast to the method of the present invention, the metallic tin for regeneration is produced by electrocoating from a tin-coated bath. Therefore, the method of the present invention avoids variations in the concentration of Sn(II) ions contained in the coating bath. It is explained as follows: When tin is deposited from an electrodeless, glued or electrode tin bath, the following reaction occurs -10 - :Feng paper size is suitable for the country's standard (CNS) A4 specification (21GX297 public) 1279456 A7 B7 Description of the invention (7)

Sn2+ + 2 e"..........> 2 Sn (1) In electrodeposition, electrons are currents derived from an external source and are transmitted to the Sn(II) ions via the cathode. In the case of electrodeless tin coating, electrons that need to deposit metal are provided by a reducing agent. In the deposition by gluing, the electrons are derived from the dissolved substrate metal - in the present case copper, on which the tin is deposited: 2 Cu..........> 2 Cu+ + 2 e' (2) In an interfering side reaction, Sn(II) ions are oxidized in these baths via oxygen from air to form Sn(IV) ions:

Sn2++ 1/2 02 + H20..........> Sn4+ + 2 OH' (3) The formed Sn(IV) tends to precipitate the cassiterite (Sn02). The nozzles associated with the problems, particularly the nozzles used to transfer the coating solution to the copper surface, can become clogged and the function of the movable parts in the processing plant can be compromised, or the parts can be damaged even by precipitated solid matter. Furthermore, the Sn(IV) ion also has an unfavorable property: the tin layer freshly deposited according to the reaction equation (1) is attacked by the Sn(IV) ion according to the reaction equation (4) proposed herein. It is dissolved again, at least in part. In the contact of the coating solution with the metal tin, the Sn(IV) ions contained in the solution are reduced to Sn(II) ions according to the following equation proposed for the reaction, and the metal tin is dissolved in the process to be proportional to each other (comproportionation) :

Sn4+ + Sn ..........> 2 Sn2+ (4) This means that for each of Sn(IV) formed, two Sn(II) ions are formed. As a result, when the regeneration method according to European Patent No. 0 545 216 A2 is used, the concentration of tin contained in the coating solution is gradually increased. -11 - The paper scale applies to the Chinese National Standard (CNS) A4 specification (210X 297 mm)

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In carrying out the process of the present invention, in contrast, the metallic tin used to reduce the Sn(IV) ions is deposited by electrolysis from a tin coating solution. The result is that the tin balance of the bath is not disturbed by the regeneration according to equation (4). The metal tin used for regeneration is also formed from Sn(II) ions according to equation (1), and thus the concentration of Sn(II) is first reduced by electrolytic deposition, and Sn(II) consumed by the reaction (1) and side reaction (3) The ions are then produced by the regeneration reaction (4). Therefore, the content of Sn(II) ions is kept constant. The process of the present invention thus allows to avoid the deleterious consequences of Sn(IV) ion formation and simultaneously regenerate Sn(II) ions from Sn(IV) ions without complicated equipment and analytical expense. The coating solution essentially comprises at least one Sn(II) compound, at least one compound from the group comprising sulfur-based urea, urea and its derivatives, and at least one acid. If the tin alloy is deposited, the solution additionally comprises at least one additional deposited metal salt, such as one or more salts of nickel, lead, mercury and/or gold. Further, the tin coating solution may also contain a binder, a reducing agent, and other component parts such as a stabilizer for controlling deposition and for ensuring decomposition of the coating solution to be stable, and a surfactant. Typically, the solution is water soluble, i.e., the solvent contained in the solution comprises at least 5 volume percent water. It may also contain organic solvents such as, for example, alcohols and ether esters.

The Sn(II) compound is preferably a Sn(n) salt of an inorganic (mineral) acid, for example, an acid containing sulfur, phosphorus and/or a halogen; however, hydrogen halide must be avoided because of its corrosive action and its tendency to be added to the halogenation. Tin to the deposited tin. Further, the Sn(n) compound may also be a Sn(II) salt of an organic acid, such as a formic acid Sn(n), an acetic acid Sn(n) and a salt thereof, and a salt of an aromatic acid, more specifically a benzoic acid Sn. (n). Preferred •12· Zhang Scale Fit® Country Material (CNS) A4 Specification (21G X 297 public) ' --------- 1279456 A7

The salts are Sn(II) salts of sulfur-containing acids, that is, salts of sulfuric acid and aminosulfonic acid (SnS〇4 and Sn(OS〇2NH2)2). Further, the solution may comprise an alkali metal stannate such as sodium stannate or stannic acid. If the tin alloy is deposited, the tin coating solution additionally contains at least one other alloy metal compound such as a salt of nickel, lead, mercury and/or gold; the anions of these salts may be the same as those used for the tin salt. For compounds of the Sn(II) compound and other alloying metals, reference is made to U.S. Patent 4,715,894. The compounds disclosed therein are hereby incorporated by reference. The acid contained in the tin coating solution is preferably a mineral acid, but may also be an organic SiL, and the anion of the acid is usually the same as that of the tin salt, and if necessary, the same as the salt of the other alloy metal. The thiourea and urea compounds used are more particularly unsubstituted derivatives (thiourea, urea), and the solution usually contains only thiourea and/or its derivatives. Suitable derivatives of thiourea and urea are indicated in U.S. Patent 4,715,894. The derivatives disclosed herein are hereby incorporated by reference. The tin coating solution may also contain a miscible agent, as indicated in the Kirk-Othmer, Encyclopedia of Chemical Technology '3rd Edition', Vol. 5, pp. 339-368. Suitable for. The complexing agents disclosed herein are hereby incorporated by reference. More specifically, an aminocarboxylic acid and a hydroxycarboxylic acid can be used. The complexing agents disclosed herein are disclosed herein and are incorporated herein by reference. The solution may also contain a reducing agent, an aldehyde, for example, more specifically using meth and acetic acid. Further, the reducing agent is indicated in U.S. Patent 4,715,894. In the -13-! This paper scale applies to the Chinese National Standard (CNS) A4 specification (210 X 297 mm)

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Line 1279456 A7 _____ B7 V. INSTRUCTIONS (10) The reductants disclosed herein are hereby incorporated by reference. Anionic, cationic and amphoteric surfactants can be similarly used. It is only concerned that the surfactant is sufficient to reduce the surface tension of the coating solution. The tin metal used for regeneration can be deposited on an inert auxiliary cathode. The electrode separated by the inert cathode means that when the electrode is anodic-polarized, it contains a substance resistant to dissolution in the tin coating solution. More specifically, the auxiliary cathode can be made of platinized titanium. The auxiliary cathode can be shaped as a flat plate, a tube, an extended metal or a flat body such as a ribbed plate. The auxiliary cathode can also be formed in a smaller piece, for example, having a spherical shape with a radius of several millimeters to several centimeters. In the latter case, the sheets can be contained in separate containers, for example, a coating solution flows through the container. For this purpose, the sheet can be placed, for example, on a perforated bottom plate contained in a column through which the coating solution enters and flows through the column. Forming the auxiliary cathode into a smaller sheet allows the conversion rate of Sn(IV) ions to Sn(II) ions to be greatly increased. If an inert auxiliary cathode is used, the maximum amount of tin which can be redissolved in the regeneration reaction according to the reaction equation (4) is the amount previously deposited from the bath. As a result, the bath can be continuously regenerated without complicated analytical bath monitoring, and the tin concentration in the bath does not increase in accordance with the method of European Patent No. 545 216 A2. If, for example, the deposition of tin onto the platinized titanium, the cathode current density set for the auxiliary cathode is sufficiently high (e.g., 8 amps/cm 2 ), a tin coating in the form of a flat gauge crystal can be obtained. This crystal shape has a very large surface which is well adapted to the regeneration reaction according to equation (4) because it is relative to tin

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• 14-1279456 A7 -----B7 V. The weight of the invention (11) provides a very large surface. As a result, the large surface of the deposited tin can be provided in a pre-measured volume of the coating solution. When the auxiliary cathode is made of copper or a copper alloy such as silver, a similar scale of deposition is also observed when a high current density is generated on the auxiliary cathode. The advantage of copper overriding inert materials such as platinized titanium is that copper is relatively inexpensive. Although the longevity of this material in chemical tin coating solutions is limited. The auxiliary cathode is in electrical contact with the coating solution. An auxiliary cathode is also provided which is in electrical contact with the coating solution directly or in electrical contact with the coating solution via another solution. By using the voltage between the auxiliary cathode and the auxiliary anode, a current is generated between the two electrodes. When tin is deposited on the auxiliary cathode, the auxiliary cathode is cathodically polarized and the auxiliary anode is anodically polarized. If the tin accumulated on the auxiliary cathode is used directly to regenerate the tin coating solution, the auxiliary cathode is not cathodically polarized during true regeneration to allow the tin to dissolve from the auxiliary cathode. Thus, in this way, the auxiliary cathode is only intermittently cathodically polarized each time the tin is deposited on the auxiliary cathode. Once sufficient tin is deposited on the auxiliary cathode, the electrical connection between the auxiliary cathode and the auxiliary anode is interrupted to terminate the deposition process. Then, the dissolution reaction according to the equation (4) of this reaction is carried out under these conditions. The coating solution must be in contact with the auxiliary cathode. Once only a small amount of tin or a little tin is left on the auxiliary cathode, tin can be redeposited on the electrode. For the regeneration reaction, the metallic tin formed on the auxiliary cathode can be directly used to coat or be mechanically removed from the contact of the tantalum solution with the metal tin coated auxiliary cathode, and After removal, it is contacted with a tin coating solution. 1279456 A7 P______B7 V. INSTRUCTION DESCRIPTION (12) In order to mechanically remove the tin deposited on the auxiliary cathode, the auxiliary cathode is preferably «taken out of the factory' and the metal scales grown thereon are peeled off. The removed tin is then placed in a container for processing the printed circuit board, or in a reservoir containing a tin coating solution. In the processing vessel or reservoir, tin is dissolved' to form Sn(II) ions, while Sn(iv) ions are consumed in the process. Once all of the portion, or at least almost all of the tin disposed in the vessel or reservoir, is dissolved, additional tin deposited on the auxiliary cathode can be added. The rate of dissolution of tin from the auxiliary cathode or metal tin removed from the auxiliary cathode and placed in the treated vessel or reservoir depends on a number of parameters: the dissolution rate of tin depends inter alia on the combination The temperature of the material and the coating bath, the morphology of the electrolytically deposited tin, the geometric surface of the auxiliary cathode, and the flow conditions immediately approaching the dissolved tin. Therefore this rate can be optimized. The maximum rate of dissolution is always the target, so under these conditions, the Sn(IV) ions are truly reduced to the Sn(II) ions. This makes it possible to minimize the concentration of Sn(IV) ions contained in the coating solution. The higher the dissolution rate, the higher the acid concentration in the tin coating solution, the higher the temperature of the bath, the larger the tin surface deposited on the auxiliary cathode 'is the greater the geometrical surface of the auxiliary cathode relative to the weight of the tin, and The higher the transfer rate of the coating solution immediately approaching the dissolved tin. In order to optimize the method of the present invention, the space around the auxiliary anode (anode space) in the electrode regenerative battery can be separated from the space around the auxiliary cathode (cathode space) by a film. A preferred form of the film is one in which the cation (Sn(n)) ion and the Sn(IV) ion cannot pass. Thus, the film may more particularly be an anion exchange membrane or a monoselective ion exchange membrane. In a particularly preferred embodiment of the method according to the invention, there is a space in the anode space

1279456 A7 B7 V. INSTRUCTIONS (13) A ----- This is contained in the coating solution in the cathode space, and the acid contained in the anode space is the same. However, when the I contained in the tin coating solution is different from the acid contained in the anode space, very good regeneration results can be obtained. For example, a sulfuric acid solution containing a burnt acid tin and a sulfuric acid solution contained in the cathode have good results. There is fluid transfer between the cathode space and the area where the tin-containing layer is deposited onto the printed circuit board. These further improvements in the method according to the present invention allow for avoiding direct contact of the tin coated ' trough bath with the auxiliary anode. Therefore, the sn(iv) ions are prevented from being formed on the auxiliary anode, which otherwise reduces the efficiency of regeneration. For example, the auxiliary anode is immersed in an anode space separate from the cathode space, which surrounds the auxiliary cathode with an anion exchange membrane. The coating solution in the cathode space, which more specifically contains, for example, SnS〇4 and ΗΑ〇4, is inaccessible to the auxiliary anode because the film prevents the passage of Sn(II) ions. The acid solution also contained in the cathode space is also preferably filled into the anode space. In the present example, the acid is H2s〇4. When the current flows between the two spaces, the electrical neutrality is ensured by the transfer of the sulfate anion and the corresponding electrode reaction, ie by the tin coating reaction on the auxiliary cathode according to the reaction equation (1) And an oxidation reaction on the auxiliary anode, wherein oxygen is formed from water according to the reaction equation (5): 2 H20.......> 2 H+ + 2 e· + 02 (5) When Sn(II) ions When avoiding contact with the auxiliary anode, Sn(II) ion oxidation according to the following equation does not occur:

Sn2+ .........> Sn4+ + 2 e· (6) In addition, the auxiliary anode may also be in direct contact with the coating solution. In this case, in order to avoid the oxidation of Sn(II) ions according to the reaction equation (6), the -17-paper scale is applied to the Chinese National Standard (CNS) A4 specification (210X 297 mm) 14 ) 1279456 DESCRIPTION OF THE INVENTION (The amount of voltage must be high enough for this reaction. This can be achieved by a suitable geometric arrangement of the auxiliary anode relative to the auxiliary cathode, for example: lack of Sn(II) ions in a solution immediately adjacent to the auxiliary cathode, which can result in By concentrating the excess voltage, it is also possible to achieve that the anode space is accommodated in a container separated from the cathode space, and the two spaces are connected via a relatively small radius line. The above-mentioned concentrated excess voltage can also be achieved by increasing the current density on the auxiliary cathode. So that the Sn(II) ions are truly no longer accessible at the immediate vicinity of the cathode. Under these conditions, the Sn(II) ions do not oxidize to form Sn(IV) ions, but the water oxidizes the form of oxygen. The current density at the auxiliary anode is For example, by adding, rather than assisting the surface of the surface of the cathode, the surface of the anode is increased. In another embodiment of the invention, at least one of the inclusions is sunken. An electrode of tin, that is, an electrode such as a metal tin, may be in contact with the tin coating solution. The tin electrode is anodically polarized with respect to the other electrode such that the tin electrode dissolves at least a portion. The soluble tin electrode may include For example, p〇ured balls, which are housed in a suitable container, such as a titanium basket (valence (4) (10) to let (9). In this case, the tin electrode is at least intermittently opposite to the other electrode and the anode Polarization causes metal tin to dissolve to form Sn(II) ions. When a soluble tin electrode is used, Sn(II) ions may be generated by dissolution in the electrolytic deposition reaction, so that the total amount of tin contained in the coating solution The amount is kept constant. Once the desired concentration of Sn(II) ions contained in the solution is reached in the process of anodic dissolution, the anodic dissolution reaction at the tin electrode can be stopped by interrupting the flow of electricity w. After reaching the soluble tin electrode, Sn(IV) ions are also reduced on this electrode, resulting in metal with the electrode. 18 - ^ Paper scale applicable to China National Standard (CNS) A4 specification (210X297 mm) --- ---— 1279456

The tin reacts to form Sn(II) ions. When a tin electrode is used, however, the tin concentration contained in the coating solution, mainly the concentration of Sn(II) ions, must be accurately monitored and analyzed, because otherwise the dissolution of the tin electrode causes the tin contained in the coating solution. The concentration exceeds the reference value. In this case, the dissolution of the tin metal of the tin electrode is not automatically limited, which is the case when only the inert auxiliary cathode is used. The tin coating solution can be contacted with the workpiece in a different manner: in a conventional manner, the workpiece is immersed in a bath of coating solution filled in the container. In this case, the arrangement with the auxiliary cathode and the auxiliary anode is placed in the same container in the free space, or the coating solution flows through the respective containers therein. A fluid conduit is provided between the processing vessel and the other regeneration vessel for this purpose, wherein the coating solution is circulated between the processing vessel and the regeneration vessel. Further, the workpiece can be processed in a so-called horizontal factory with a coating chamber. In this horizontal factory, the work piece is transported through the chamber in a horizontal transport direction. In this case, when the workpiece is transported through the chamber, the coating bath is transported to the copper surface of the workpiece by means of a nozzle, such as a spray nozzle, a flow nozzle, a spray nozzle or the like. For this purpose, the solution is held in the reservoir by means of a pump from which it is transported to the nozzle. After the coating solution is in contact with the steel surface, it is discharged to the collection tank via the fluid conduit, from the supply tank to the collection tank. In this case, the arrangement of the auxiliary cathode and the auxiliary anode is accommodated in the storage tank, or in separate In the regeneration container. Therefore, a method of depositing a metal layer and a method of regenerating a solution containing a metal ion of a high oxidation state, in particular, a solution containing Sn(IV) ions, will be described. Although the specific embodiments are described, including: specific equipment, method steps, method parameters, substances, solutions, etc., different changes to the disclosed specific embodiments, It is obvious that this artist is reading this disclosure. Therefore, it is to be understood that the invention is not intended to be limited -20- , the paper scale applies to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) V· } ·

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Claims (1)

^94#69ΤΓΓ^655 Patent Application as Scope Replacement (September 95) g Fan Yuan '祝鳞承丨月HJ f ~ 1. A method of depositing tin or tin alloy layer, including the following method steps·· a. a tin or tin alloy coating bath comprising at least one inorganic acid or an organic acid of Sn(II), a salt and at least one acid having the same anion as the at least one tin salt; b. from the tin or tin alloy Depositing a tin or tin alloy layer onto the workpiece in the coating bath by contacting the workpiece with the tin or tin alloy coating bath to pass the workpiece through the tin contained in the processing vessel Or in a tin alloy coating bath or by processing the workpiece in a coating chamber in a horizontal factory; c. contacting the tin or tin alloy coating bath with the tin metal for regeneration to be included in The Sn(IV) ion of the tin or tin alloy coating bath is reduced to Sn(II) ions by moving the tin or tin alloy coating bath into an individual regeneration vessel containing an electrolytic regeneration battery, the regeneration The container contains tin metal for regeneration, and the regeneration container is Disposing the processing container separately and separately from the processing container or the coating chamber, or by contacting the tin or tin alloy coating bath with the tin metal in a processing container, the electrolytic regeneration battery being included in the treatment In the container, wherein the electrolytic regenerative battery is sinusoidal, 丨, 匕3, at least one inert auxiliary cathode or at least one 锸meng wind 夂 auxiliary cathode made of copper or copper alloy, and at least one auxiliary anode, and In the electrolytic regenerative battery, you can proceed to the following steps: i) to apply electricity from the tin or tin alloy coating bath by applying a voltage between the auxiliary cathode and the auxiliary rib to the auxiliary assisting electrode. a tin metal for regeneration is deposited on the at least one auxiliary cathode; and 11 the tin metal for regeneration is attached to the bath material of the 79082-950929.doc 蜀〃Child tin or tin alloy. Fresh (CNS) A4 specification (_ χ诺公董) A8 B8 C8 1279456 is contacted to reduce Sn(IV) ions to S n (11) ions by contact with the tin metal for regeneration, by mechanically removing the tin metal for regeneration from the auxiliary cathode, and thereafter The tin metal for regeneration is brought into contact with the tin or tin alloy coating bath, or by intermittently contacting the tin or tin alloy coating bath with the auxiliary cathode unpolarized. 2. The method of claim 2, wherein the at least one auxiliary cathode is made of platinized titanium. 3. The method of claim </ RTI> wherein the tin is deposited as a scale on the at least one auxiliary cathode by adjusting the cathode current density. 4. The method of claim i, wherein the at least one auxiliary anode is separated from the space surrounding the at least one auxiliary cathode by a film. 5. The method of claim 4, wherein the film is mounted such that the Sn(II) ion and the Sn(IV) ion do not penetrate the film. 6. The method of claim 4, wherein the film is an anion exchange film or a single selective ion exchange film. 7. The method of claim 4, wherein the acid is supplied to the space surrounding the at least one auxiliary cathode. 8. The method of claim 1, wherein the at least one electrode comprising tin is in contact with the tin or tin alloy coating bath, and wherein the at least one electrode is anodic polarized with respect to at least one other electrode, At least one of the electrodes comprising tin is at least partially dissolved. 9. The method of claiming the patent scope &quot; member, wherein the workpiece is used to sink 79082-950929.doc n Ϊ 279456, the patent application area The coating chamber of the metal sheet is transported in a horizontal direction. 〇 — — — — — 含 含 含 含 含 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液 溶液(II) wherein 'providing an electrolytic heterogeneous φ electrolytic regenerative battery comprising at least one inert auxiliary cathode or at least one auxiliary cathode made of copper or a copper alloy and a small number of auxiliary anodes, and the method comprises the following Method steps: 1) applying a voltage between the auxiliary auxiliary cathode and the auxiliary anode, so that the tin metal for regeneration from the tin or tin alloy coating bath is accumulated on the at least one auxiliary cathode丨和··) will. The metal tin for regeneration is contacted with the tin or tin alloy coating bath to bring the Sn(IV) ions into contact with the tin metal for regeneration to be reduced to S n (11) ions by mechanically from the auxiliary cathode Removing the tin metal for regeneration, and then contacting the tin metal for regeneration with the tin or tin alloy coating bath, or by intermittently coating the tin or tin alloy with the auxiliary cathode unpolarized Cover the bath to contact. -3 79082-950929.doc This paper is based on the Chinese National Standard (CNS) 银4 specification (210X 297 mm).