CN1524132A - Regeneration method for a plating solution - Google Patents
Regeneration method for a plating solution Download PDFInfo
- Publication number
- CN1524132A CN1524132A CNA028135822A CN02813582A CN1524132A CN 1524132 A CN1524132 A CN 1524132A CN A028135822 A CNA028135822 A CN A028135822A CN 02813582 A CN02813582 A CN 02813582A CN 1524132 A CN1524132 A CN 1524132A
- Authority
- CN
- China
- Prior art keywords
- metal
- tin
- ions
- auxiliary cathode
- oxidation state
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/1601—Process or apparatus
- C23C18/1617—Purification and regeneration of coating baths
Landscapes
- Chemical & Material Sciences (AREA)
- Metallurgy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Electroplating Methods And Accessories (AREA)
- Chemically Coating (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Electrolytic Production Of Metals (AREA)
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
Technical Field
The invention relates to a method for depositing metal layers, more particularly tin-containing layers, in particular for producing printed circuit boards and other circuit carriers; and to a method for regenerating a solution containing metal ions in a high oxidation state, more particularly sn (iv) ions. The electroplating method is mainly used for the production of solderable layers and etch-resistant layers and for the deposition of conductive patterns made of copper, more particularly on the inner layers of printed circuit boards, by gluing a tin layer to join said inner layers together.
Background
For the manufacture of printed circuit boards, tin and tin alloy layers, more specifically tin-lead coatings, are deposited on copper surfaces for various purposes.
In one aspect, a tin-lead alloy coating is used as a solder pad on a printed circuit board where electronic components are soldered. In this case, the layer is locally deposited in those areas where the connection elements of lead or other component parts are electrically connected to the copper surface. After forming the solder areas on the copper surfaces, the components are secured to the pads where they are bonded. The solder is then remelted in an oven to allow for the formation of electronic interconnects.
Tin layers may also be used as etch resists, for example: a metal pattern is formed on a surface of the printed circuit board. For this purpose, a negative image of the conductive pattern may first be formed on the copper surface by means of a photo-patterned resist. A tin or tin-lead alloy layer is then deposited in the channel of the resist layer. After the resist is removed, the bare copper can be removed by etching so that only traces of the circuit and all other metal patterns remain under the tin or tin-lead alloy layer on the surface of the printed circuit board.
Furthermore, tin layers are also used as an interlayer between the inner copper surface of a multilayer circuit board and a dielectric region (typically a fiberglass reinforced layer of resin), and in order to provide a tight bond between the copper region and the dielectric, the copper surface needs to be roughened prior to extrusion in order to achieve sufficient bond strength between the copper and the resin. For this reason, the surface is currently surface-oxidized by a so-called black oxide treatment. However, the oxide layer thus formed is not sufficiently resistant to acid, so that the inner layer, which is cut during drilling of the PCB material, is delaminated from the resin of the PCB material, forming a delamination. This problem is avoided when a tin layer is used instead of the black oxide layer, which is deposited directly for production by gluing to the copper surface of the circuit trace. In a post-treatment, a further cementitious compound is applied to the tin layer (for example a mixture of ureido silane and disilane crosslinker (EP 0545216a2)) before the inner layers are pressed together by the action of heat and pressure, if desired.
Whereas in the second mentioned application tin or a tin-lead alloy layer, respectively, can be electrolytically deposited when the non-galvanically isolated metal areas have to be plated with tin, in the first and last mentioned case tin is not deposited by electrolytic methods, because the metal plated copper areas are usually electrically isolated from each other, so that they cannot establish an electrical contact. For this reason, so-called cementation baths are subsequently used for tin electroplating.
Such an electroplating bath is disclosed in US 4,715,894. In addition to the sn (ii) compounds, the bath also contains thiourea compounds and urea compounds, according to EP 0545216a2 thiourea, urea and derivatives thereof may also be used as alternatives. Furthermore, the solution according to US 4,715,894 also comprises a complexing agent, a reducing agent and an acid. The Sn (II) compounds used are, for example, SnSO4. According to EP 0545216a2, the bath comprises sn (ii) compounds of inorganic (mineral) acids, such as: acid compounds containing sulfur, phosphorus and halogen; or organic acid compounds, such as: sn (II) formate and Sn (II) acetate. According to EP 0545216a2, sn (ii) salts of sulfur-containing acids are preferred, i.e.: salts of sulfuric acid or sulfamic acid. Furthermore, the bath may also contain alkali metal stannates, such as: sodium stannate or potassium stannate. Furthermore, in the simplest case, thiourea and urea compounds are unsubstituted derivatives of thiourea and urea, respectively, which according to EP 0545216A2 form on the copper surface when tin is depositedCu (i) ions complexed with thiourea. At the same time, metallic tin is deposited by reduction of sn (ii) ions, in which reaction copper is dissolved, forming a tin coating on the copper surface.
EP 0545216a2 discloses that cu (i) thiourea complexes are enriched in solution. When oxygen from air is brought into solution, sn (iv) ions are also enriched in solution via oxidation of sn (ii) ions. However, when the printed circuit board is only immersed in the solution for treatment, the concentrations of the cu (i) thiourea complex and sn (iv) ions do not exceed a fixed concentration value because the bath solution is permanently drained by the board anddiluted by the entrained water. However, if the bath fluid is sprayed onto the copper surface in the form of a nozzle, the material circulation rate relative to the bath volume is rather high. In these cases, the concentration of the cu (i) thiourea complex increases to the point where it reaches the solubility limit, and the complex precipitates as a precipitate. Deposits block the nozzles and cause problems on the movable mechanical parts of the equipment, in the electroplating baths, when air is brought into the bath solution in larger portions by spraying the bath solution onto the printed circuit boards, sn (iv) compounds are also increasingly formed by oxidation of sn (ii) ions via oxygen from the air.
In order to reduce these problems, the following provisions are disclosed in the mentioned documents: in order to reduce the concentration of the cu (i) thiourea complex, a portion of the solution of the electroplating bath is carried from the treatment vessel to another tank where it is left to cool, so that a large portion of the complex precipitates and is thus isolated. The now substantially complex-free solution is then sent to a treatment vessel. To further reduce the concentration of Sn (IV) ions in the plating solution, a reservoir for the plating solution is provided which contains metallic tin. The solution contained in the reservoir is sprayed onto the copper surface, the sn (ii) ions are reduced according to the following reaction formula (1), and the metallic copper is simultaneously oxidized according to the following reaction formula (2) to form cu (i) ions. Complexes with thiourea or derivatives thereof, respectively, are thus formed. At the same time, by the oxygen brought into solution, part of the Sn (II) ions are oxidized according to the following reaction formula (3) to form Sn (IV) ions. The sprayed solution is then sent to a storage tank. Here, sn (iv) ions are reacted with metallic tin according to the following reaction formula (4) to form double times of sn (ii) ions.
However, the method of regenerating a tin electroplating cementation bath disclosed in EP 0545216a2 proved to result in a continuous increase in the concentration of tin contained in the solution. Therefore, the concentration of Sn (II) ions in the solution must be permanently analytically controlled. This is generally not possible under manufacturing conditions and often tends to result in widely varying concentrations. The result is: the deposition of tin may become uncontrollable. This is unacceptable. One approach to overcoming this problem involves automatic monitoring of the concentration of sn (ii) ions and allowing or excluding contact between the plating solution and metallic tin in the reservoir when a reference value of a pre-measured range is exceeded or not reached, respectively. This is very complex and requires a rather complex device.
Disclosure of Invention
It is therefore an object of the present invention to overcome the mentioned problems and to provide a method allowing for tin electroplating of copper surfaces by cementation without the variation of the sn (ii) ion content affecting the tin deposition. The aim is to make this possible without using complex devices.
One solution to this object is the electroplating method of claim 1 and the regeneration method of claim 14. Preferred embodiments of the invention are indicated in the dependent claims.
The electroplating method according to the invention is used to produce a metal layer, more particularly a tin-containing layer, and preferably a pure tin layer. The method can also be used to deposit layers composed of tin alloys. The method comprises the following steps:
a. providing a metal plating bath, more specifically a tin platingbath; comprising metal ions in a low oxidation state, more particularly Sn (II) ions;
b. depositing a metal layer from a metal plating bath onto a workpiece;
c. providing an electrolytic regeneration cell comprising at least one auxiliary cathode and at least one auxiliary anode;
d. in an electrolytic regeneration cell, electrolytically depositing a metal for regeneration, more particularly metallic tin, from a metal plating bath onto at least one auxiliary cathode;
e. the metal plating bath is contacted with the metal for regeneration in order to reduce the high oxidation state metal ions, in particular sn (iv) ions, contained in the metal plating bath to low oxidation state metal ions, more particularly sn (ii) ions.
The regeneration process of the present invention is used to regenerate a solution containing high oxidation state metal ions, more specifically sn (iv) ions, to reduce the high oxidation state metal ions to low oxidation state metal ions, more specifically sn (ii) ions. This comprises the following method steps:
a. providing an electrolytic regeneration cell comprising at least one auxiliary cathode and at least one auxiliary anode;
b. in an electrolytic regeneration cell, electrowinning a metal for regeneration, more particularly metallic tin, from a solution onto at least one auxiliary cathode;
c. the solution is contacted with a metal for regeneration to reduce the high oxidation state metal ions, more specifically sn (iv) ions, to low oxidation state metal ions, more specifically sn (ii) ions.
When a tin-containing layer, a tin plating bath or tin plating solution, metallic tin, sn (ii) ions, sn (iv) ions, and a tin electrode or tin-containing electrode, respectively, are hereinafter referred to, this should also be applied generally and replaced by a metallic layer, a metallic plating bath, a metal, low oxidation state metal ions, high oxidation state metal ions, a metal electrode, or a metal-containing electrode.
The method of the invention can be applied more particularly to the electroless deposition of tin or tin alloys, for the electrolytic deposition of tin and tin alloys, and deposition by cementation of tin or tin alloys, using reducing agents.
By a deposition method of cementation, it is meant that the metal to be deposited acquires the required electrons from the base metal for reduction to the oxidation state zero, which base metal is simultaneously oxidized and preferably thus dissolved.
The method of the present invention is more particularly useful for coating copper surfaces with tin-containing layers onto printed circuit boards or other circuit carriers.
In the method described in EP 0545216a2, metallic tin is added to a plating solution contained in a reservoir to convert sn (iv) ions to sn (ii) ions. In contrast, the metallic tin used for regeneration by the method of the present invention is produced by electroplating from a tin electroplating bath, and therefore the method of the present invention avoids variations in the concentration of Sn (II) ions contained in the electroplating bath. This can be explained as follows:
when tin is deposited from an electroless, cementitious or electrolytic tin bath, the following reactions occur
In electrodeposition, electrons are electrical current originating from an external source and pass through the cathode to the sn (ii) ions. In the case of electroless tin plating, the electrons neededto deposit the metal are provided by the reducing agent. In deposition by cementation, the electrons originate from dissolving the substrate metal. Copper in the present case, on which tin is deposited:
in an interfering side reaction, sn (ii) ions are oxidized in the baths via oxygen from air to form sn (iv) ions:
the Sn (IV) ions formed tend to precipitate cassiterite (SnO)2). Problems associated therewith are that, in particular, the nozzles used for delivering the plating solution to the copper surface can clog up and the function of the movable parts in the processing equipment can be impaired, or the parts can even be impaired by precipitated solid matter. Furthermore, the sn (iv) ions also have unfavorable properties: the freshly deposited tin layer according to equation (1) is attacked by the sn (iv) ions according to equation (4) set forth below, so that it is re-dissolved, at least in part.
In the contact of the plating solution with metallic tin, the sn (iv) ions contained in the solution are reduced to sn (ii) ions according to the following reaction formula proposed for this reaction, and metallic tin is dissolved in the process in proportion to each other (complexation):
this means that for each sn (iv) ion formed, two sn (ii) ions are formed, with the result that: when the regeneration method according to EP 0545216a2 is used, the tin concentration contained in the plating solution gradually increases.
In carrying out the method of the present invention, in contrast, the metallic tin used to reduce the Sn (IV) ions is derived from the tin plating solution via electrodeposition. The result is: the tin balance of the bath is not disturbed by the regeneration according to equation (4). Metallic tin for regeneration is also formed from sn (ii) ions according to equation (1), and thus the concentration of sn (ii) is first reduced by electrodeposition, sn (ii) ions consumed by this reaction (1) and side reaction (3), and then generated by the regeneration reaction (4). The sn (ii) ion content is thus maintained constant.
The method of the present invention thus allows avoiding the deleterious consequences caused by sn (iv) ion formation and at the same time regenerating sn (ii) ions from sn (iv) ions without complex equipment and analytical expenditure.
Detailed Description
The plating bath substantially comprises at least one sn (ii) compound, at least one compound from the group: thiourea, urea and derivatives thereof, and comprising at least one acid. If a tin alloy is deposited, the solution additionally contains at least one metal salt which is additionally deposited, for example: one or more salts of nickel, lead, mercury and/or gold. Furthermore, the tin plating solution may also contain complexing agents, reducing agents and other components, such as: stabilizers for controlling deposition and for ensuring stability of the plating bath against decomposition, and surfactants. Typically, the solution is aqueous, i.e. the solvent comprised in the solution consists of at least 50% by volume of water. It may also contain organic solvents, such as: alcohols and ether esters.
The sn (ii) compound is preferably a sn (ii) salt of an inorganic (mineral) acid, for example: containing sulfur,Acids of phosphorus and/or halogen; however, hydrogen halides must be avoided because of their corrosive effect and their tendency to add tin halides to the tin deposit. Furthermore, the Sn (II) compound may also be a Sn (II) salt of an organic acid, such as: salts of sn (ii) formate, sn (ii) acetate and homologues thereof and aromatic acids, more particularly sn (ii) benzoate, preferred salts are sn (ii) salts of sulphur-containing acids, i.e.: salts of sulfuric acid and sulfamic acid (SnSO)4And Sn (OSO)2NH2)2). The solution may also contain alkali metal stannates, such as: sodium stannate or potassium stannate.
If a tin alloy is deposited, the tin plating solution additionally contains a compound of at least one other alloying metal, such as: salts of nickel, lead, mercury and/or gold; the anions of these salts may be the same as those used for tin salts.
With regard to sn (ii) compounds and compounds of other alloying metals, reference is made to US 4,715,894. The compounds disclosed therein are incorporated herein by reference.
The acid contained in the tin plating bath is preferably a mineral acid, but may also be an organic acid, the anion of which is generally the same as the anion of the tin salt and, if necessary, of the salt of the other alloy metal.
The thiourea and urea used are more particularly unsubstituted derivatives (thiourea, urea), the solution usually only comprising thiourea and/or derivatives thereof, suitable derivatives of thiourea and urea are disclosed in US 4,715,894. The derivatives disclosed therein are incorporated herein by reference.
The tin electroplating solution may also contain complexing agents, particularly suitable being those indicated in Kirk-Othmer, Encyclopedia of chemical Technology, third edition, Vol.5, p.339-. The complexing agents disclosed therein are incorporated herein by reference. More specifically, aminocarboxylic acids and hydroxycarboxylic acids can be used. The complexing agents disclosed therein are incorporated herein by reference.
The solution may also contain reducing agents, aldehydes, such as: more specifically formaldehyde and acetaldehyde are used, and furthermore, a reducing agent is disclosed in US 4,715,894. The reductants disclosed therein are incorporated herein by reference.
Anionic, cationic and amphoteric surfactants can be similarly used. It is relevant only that the surfactant be sufficient to suitably reduce the surface tension of the plating solution.
The tin metal used for regeneration may be deposited on an inert auxiliary cathode. By inert cathode, a separate electrode is meant that when the electrode is anodically polarized, it contains a substance that is resistant to dissolution in the tin plating solution. More specifically, the auxiliary cathode may be made of platinized titanium.
The auxiliary cathode can be shaped as a flat plate, a tube, an extended metal or a formed body such as a flat plate with ribs. The auxiliary cathode may also be formed in a pellet shape, for example, having a spherical shape with a diameter of several millimeters to several centimeters. In the latter case, the tablets may be contained in separate containers, for example: plating solution flows through the vessel. For this purpose, the sheet can be placed, for example, on a perforated base plate accommodated in a tower, through which the plating solution enters and flows through the tower. Shaping the auxiliary cathode into smaller pieces allows for a substantial increase in the rate of conversion of sn (iv) ions to sn (ii) ions.
If an inert auxiliary cathode is used, the maximum amount of tin that can be redissolved in the regeneration reaction is the amount deposited from the bath as described above, according to equation (4). The result is: the bath can be continuously regenerated without complicated analytical bath monitoring and the tin concentration in the bath does not rise in comparison with the method according to EP 0545216a 2.
If, for example, tin is deposited on platinized titanium, the cathodic current density set for the auxiliary cathode is sufficiently high (for example: 8 amperes per square decimeter), it is possible to obtain a tin coating in the form of flat-scale crystals having a very large surface, which is well suited to the regeneration reaction according to equation (4), since it provides a very large surface with respect to the weight of tin. The result is: the large surface on which the tin is deposited may be provided in a predetermined volume of the plating solution. When the auxiliary cathode is made of copper or a copper alloy, for example with silver, a deposition of similar scale is also observed when a high current density is generated on the auxiliary cathode. An advantage of copper over inert materials such as platinized titanium is that copper is less expensive. Although the long-term life of this material in electroless tin plating solutions is limited.
The auxiliary cathode is in electrical contact with the electroplating solution. An auxiliary cathode is also provided which is in electrical contact with the plating solution either directly or via another solution. By applying a voltage between the auxiliary cathode and the auxiliary anode, a current is generated between these two electrodes, the auxiliary cathode being cathodically polarized and the auxiliary anode being anodically polarized when tin is deposited on the auxiliary cathode. If the tin deposited on the auxiliary cathode is used directly to regenerate the tin plating solution, the auxiliary cathode is not cathodically polarized during the actual regeneration to allow the tin to dissolve from the auxiliary cathode. Thus, in this way, the auxiliary cathode is cathodically polarized only intermittently each time tin is deposited on the auxiliary cathode. Once sufficient tin has been deposited on the auxiliary cathode, the electrical connection between the auxiliary cathode and the auxiliary anode is interrupted, so that the deposition process is halted. Then, the dissolution reaction of the reaction formula (4) according to this reaction is carried out under these conditions. The plating solution must be in contact with the auxiliary cathode. Once only a small amount of tin or no tin at all remains on the auxiliary cathode, tin can redeposit on the electrode.
For the regeneration reaction, the metallic tin formed on the auxiliary cathode may be used directly to bring the plating solution into contact with the auxiliary cathode plated with metallic tin, or mechanically removed from the electrode and, after its removal, brought into contact with the tin plating solution.
In order to mechanically remove the tin deposited on the auxiliary cathode, the auxiliary cathode is preferably removed from the apparatus and the metal scale grown thereon is exfoliated. The tin removed is then placed in a vessel for treating printed circuit boards or in a reservoir containing a tin plating solution. In the treatment vessel or reservoir, the tin dissolves to form Sn (II) ions, which are consumed in the process. Once all, or at least almost all, of the tin placed in the container or reservoir is dissolved, additional tin deposited on the auxiliary cathode may be added.
The rate of dissolution of tin from the auxiliary cathode, or metallic tin removed from the auxiliary cathode and placed in the processing vessel or reservoir, in the plating solution depends on a number of parameters: the rate of dissolution of tin depends, among other things, on the composition, on the temperature of the electroplating bath, the morphology of the electrolytically depositedtin, the geometric surface of the auxiliary cathode and the flow conditions immediately approaching that of the dissolved tin. The rate can be optimized. The maximum dissolution rate is always targeted because under these conditions, sn (iv) ions are truly quantitatively reduced to sn (ii) ions. This makes it possible to minimize the concentration of Sn (IV) ions contained in the plating solution. The higher the dissolution rate, the higher the acid concentration in the tin plating bath, the higher the temperature of the bath, the larger the tin surface deposited on the auxiliary cathode, the larger the geometric surface of the auxiliary cathode relative to the weight of tin, and the higher the convection of the plating bath immediately adjacent to the dissolved tin.
To optimize the process of the present invention, the space around the auxiliary anode (anode space) may be separated from the space around the auxiliary cathode (cathode space) by a membrane in an electrode regenerative cell. The membrane is preferably configured such that cations (Sn (II)) and Sn (IV)) are not able to pass through. Thus, the membrane may more specifically be an anion exchange membrane or a monoselective ion exchange membrane. In a particularly preferred embodiment of the process according to the invention, there is an acid in the anodic space. The acid contained in the plating solution in the cathode space may be the same as the acid contained in the anode space. However, very good regeneration results can also be obtained when the acid contained in the tin plating solution is different from the acid contained in the anode space. For example: the plating solution containing tin methane sulfonate and the sulfuric acid solution contained in the cathode space gave good results. There is a transfer of fluid between the cathode space and the area where the tin-containing layer is deposited onto the printed circuit board.
These further improvements of the method according to the invention allow to avoid that the tin electroplating bath directly contacts the auxiliary anode. The formation of sn (iv) ions on the auxiliary anode, which would otherwise reduce the efficiency of regeneration, is thus avoided. For example: the auxiliary anode may be immersed in an anode space separate from a cathode space surrounding the auxiliary cathode with an anion exchange membrane. An electroplating solution in the cathode space, which more specifically comprises, for example: SnSO4And H2SO4The auxiliary anode cannot be accessed because the film prevents the passage of sn (ii) ions. Also comprisesThe acid solution in the cathode space is also preferably filled into the anode space. In this example, the acid is H2SO4. When an electric current flows between the two spaces, electroneutrality is ensured by the transfer of sulfate anions and the corresponding electrode reactions, namely: by the tin electroplating reaction on the auxiliary cathode of the reaction formula (1) according to this reactionAnd an oxidation reaction at the auxiliary anode, wherein oxygen is formed from water according to equation (5):
when sn (ii) ions are avoided from contacting the auxiliary anode, oxidation of sn (ii) ions according to the following reaction formula does not occur:
alternatively, the auxiliary anode may be in direct contact with the tin plating solution. In this case, too, to avoid oxidation of sn (ii) ions according to equation (6), the concentration overpotential must be sufficiently high for this reaction. This can be achieved by a suitable geometrical configuration of the auxiliary anode with respect to the auxiliary cathode, for example: the lack of sn (ii) ions in the solution immediately adjacent to the auxiliary cathode, which would result in a concentration overpotential, can also be achieved by the anode space being contained in a container separate from the cathode space, the two spaces being in communication via a relatively small diameter tube.
The above-described concentration overpotential may also be achieved by substantially increasing the current density at the auxiliary cathode such that sn (ii) ions are not actually available in the immediate vicinity of the auxiliary cathode. Under these conditions, the Sn (II) ions do not oxidize to form Sn (IV) ions, but water oxidizes to form oxygen. The current density at the auxiliary anode is increased, for example, by reducing the surface of the auxiliary anode relative to the surface of the auxiliary cathode.
In another embodiment of the invention, at least one electrode comprising the tin to be deposited, i.e. for example an electrode of metallic tin, may be contacted with the tin electroplating solution. The tin electrode is anodically polarized relative to the other electrode such that the tin electrode dissolves at least a portion. Such soluble tin electrodes may comprise, for example, cast balls (potted balls) in a suitable container, such as: titanium basket (titanumbasket).
In this case, the tin electrode is anodically polarized at least intermittently relative to the other electrode such that the metallic tin dissolves to form sn (ii) ions.
When a soluble tin electrode is used, sn (ii) ions can be generated by dissolution consumed in the electrodeposition reaction so that the total amount of tin contained in the plating solution is kept constant. Once the desired concentration of sn (ii) ions contained in the solution is reached during anodic dissolution, the anodic dissolution reaction at the tin electrode can be terminated by interrupting the current flow. After the current is no longer supplied to the soluble tin electrode, the sn (iv) ions are also reduced at this electrode, causing them to react with the metallic tin of the electrode to form sn (ii) ions.
However, when tin electrodes are used, the concentration of tin contained in the plating solution, mainly the concentration of Sn (II) ions, must be accurately monitored analytically, since otherwise the dissolution of the tin electrode would cause the concentration of tin contained in the plating solution to exceed the reference value. In this case, the dissolution of metallic tin of the tin electrode is not automatically limited, which is the case when only an inert auxiliary cathode is used.
The tin plating solution can be contacted with the workpiece in different ways: in a conventional manner, the workpiece is immersed in a bath of plating liquid filled in a container. In this case, the auxiliary cathode and the auxiliary anode are arranged in the same container in free space or in separate containers through which the plating solution flows. For this purpose, a fluid conduit is provided between the treatment vessel and the other regeneration vessel, in which plating solution can be circulated between the treatment vessel and the regeneration vessel.
Furthermore, the workpieces can be processed in so-called horizontal apparatuses with coating chambers. In the horizontal apparatus, the workpiece is conveyed in a horizontal conveyance direction via the chamber. In this case, when the workpiece is transported through the chamber, the plating solution passes through nozzles such as: spray nozzles, flow nozzles, spray nozzles or the like are delivered to the copper surface of the workpiece. For this purpose, the solution is held in a reservoir, from which the solution is conveyed by a pump to the nozzle. After the plating solution contacts the copper surface, it is drained into a collection tank, from where it is returned to the reservoir via a fluid conduit. In this case, the arrangement of auxiliary cathode and auxiliary anode is housed in the reservoir, or in a separate regeneration vessel.
Accordingly, a method for depositing a metal layer and a method for regenerating a solution containing metal ions in a high oxidation state, in particular Sn (IV) ions, are disclosed. Although specific embodiments are described, including: specific equipment, method steps, method parameters, materials, solutions, etc., but different variations on the disclosed embodiments will be apparent to those skilled in the art upon reading this disclosure. Accordingly, it is to be understood that this embodiment is for purposes of illustration only and is not to be construed as limiting the broad invention, and that the invention is not to be limited to the specific embodiments described, but rather is to be defined by the scope of the appended claims.
Claims (15)
1. A method of depositing a metal layer, comprising the method steps of:
a. preparing a metal plating bath containing metal ions in a low oxidation state;
b. depositing a metal layer from a metal plating bath onto a workpiece;
c. bringing the metal plating bath into contact with a metal for regeneration, reducing the metal ions in a high oxidation state contained in the metal plating bath to metal ions in a low oxidation state,
wherein an electrolytic regeneration cell comprising at least one auxiliary cathode and at least one auxiliary anode is provided and the metal for regeneration is electrolytically deposited from the metal plating bath onto the at least one auxiliary cathode.
2. The method of claim 1, wherein the method is used to deposit a tin-containing layer and the metal ions in the low oxidation state are sn (ii) ions, the metal ions in the high oxidation state are sn (iv) ions, and the metal is metallic tin.
3. The method of claim 1 or 2, wherein said at least one auxiliary cathode is made of copper or a copper alloy.
4. The method of claim 1 or 2, wherein said at least one auxiliary cathode is made of an inert material.
5. The method of claim 4, wherein said at least one auxiliary cathode is made of platinized titanium.
6. The process according to any one of claims 1 to 5, wherein the metal is deposited on the at least one auxiliary cathode in the form of an oxide scale by adjusting the cathodic current density.
7. The process as claimed in any of claims 1 to 6, wherein the metal deposited on the at least one auxiliary cathode is mechanically removed and, after removal, wherein the metal is brought into contact with a metal plating bath, the metal ions in the higher oxidation state contained in the reduced metal plating bath are metal ions in the lower oxidation state.
8. The method according to any of claims 1 to 7, wherein the at least one auxiliary anode is separated from the space surrounding the at least one auxiliary cathode by a membrane.
9. The method of claim 8, wherein the membrane is configured such that the membrane is impermeable to metal ions.
10. A process according to claim 8 or 9 wherein the membrane is an anion exchange membrane or a monoselective ion exchange membrane.
11. The method of any one of claims 8-10, wherein acid is provided to a space surrounding the at least one auxiliary cathode.
12. The method of one of claims 1 to 11, wherein at least one electrode containing the metal to be deposited is in contact with a metal plating bath and the at least one electrode is anodically polarized with respect to at least one other electrode such that the at least one electrode containing the metal to be deposited is at least partially dissolved.
13. The method of one of claims 1 to 12, wherein the workpiece is transported in a horizontal direction through a coating chamber for depositing a metal layer.
14. A process for regenerating a solution containing metal ions in a high oxidation state, in which process the solution is contacted with a metal for regeneration to reduce the metal ions in the high oxidation state to metal ions in a low oxidation state,
wherein an electrolytic regeneration cell is provided comprising at least one auxiliary cathode and at least one auxiliary anode, and metal for regeneration is electrolytically deposited from solution onto the at least one auxiliary cathode.
15. The process of claim 14, wherein the process is used to regenerate a tin-containing solution and the metal ions in the low oxidation state are sn (ii) ions, the metal ions in the high oxidation state are sn (iv) ions, and the metal is metallic tin.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10132478.2 | 2001-07-03 | ||
| DE10132478A DE10132478C1 (en) | 2001-07-03 | 2001-07-03 | Process for depositing a metal layer and process for regenerating a solution containing metal ions in a high oxidation state |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1524132A true CN1524132A (en) | 2004-08-25 |
| CN1232677C CN1232677C (en) | 2005-12-21 |
Family
ID=7690626
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB028135822A Expired - Lifetime CN1232677C (en) | 2001-07-03 | 2002-06-17 | Regeneration method for a plating solution |
Country Status (16)
| Country | Link |
|---|---|
| US (1) | US20040245108A1 (en) |
| EP (1) | EP1427869B1 (en) |
| JP (1) | JP4157838B2 (en) |
| KR (1) | KR100827259B1 (en) |
| CN (1) | CN1232677C (en) |
| AT (1) | ATE289633T1 (en) |
| AU (1) | AU2002321069A1 (en) |
| BR (1) | BR0210829B1 (en) |
| CA (1) | CA2450258A1 (en) |
| DE (2) | DE10132478C1 (en) |
| ES (1) | ES2236552T3 (en) |
| HK (1) | HK1062926A1 (en) |
| MX (1) | MXPA03011772A (en) |
| MY (1) | MY130423A (en) |
| TW (1) | TWI279456B (en) |
| WO (1) | WO2003004725A2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102586851A (en) * | 2011-01-06 | 2012-07-18 | 宝山钢铁股份有限公司 | Electrolytic method for relieving and reducing tin sludge generated in tin plating solution |
| CN106011810A (en) * | 2016-06-02 | 2016-10-12 | 深圳市创智成功科技有限公司 | Removing process of tetravalent tin in chemical tin plating liquid of copper substrate |
| CN106811773A (en) * | 2015-05-12 | 2017-06-09 | 江苏理工学院 | Supercritical composite electroforming system recycling device |
| CN110387540A (en) * | 2019-08-30 | 2019-10-29 | 江苏上达电子有限公司 | Stannous replenishment system and method in a kind of tin dissolving slot |
| CN111676470A (en) * | 2020-05-29 | 2020-09-18 | 广东天承科技有限公司 | Simple and soluble high-valence tin reduction method |
| CN116288292A (en) * | 2023-03-20 | 2023-06-23 | 聂柱根 | Chemical tin liquid tin reduction regeneration copper removal device |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GEP20105122B (en) | 2003-07-16 | 2010-11-25 | Interdigital Tech Corp | Method and system for transferring information between network management entities of a wireless communication system |
| EP1630252A1 (en) * | 2004-08-27 | 2006-03-01 | ATOTECH Deutschland GmbH | Process for coating antimony containing substrate with tin or tin alloys |
| JP4998704B2 (en) | 2007-01-22 | 2012-08-15 | 上村工業株式会社 | Method for forming substituted tin alloy plating film, substituted tin alloy plating bath, and method for maintaining plating performance |
| EP2298960A1 (en) | 2009-08-24 | 2011-03-23 | ATOTECH Deutschland GmbH | Method for electroless plating of tin and tin alloys |
| DE102009060676B4 (en) | 2009-12-28 | 2015-07-23 | Atotech Deutschland Gmbh | Process and device for wet-chemical treatment of items to be treated |
| EP2671968B1 (en) * | 2012-06-05 | 2014-11-26 | ATOTECH Deutschland GmbH | Method and regeneration apparatus for regenerating a plating composition |
| WO2018077874A1 (en) * | 2016-10-24 | 2018-05-03 | Atotech Deutschland Gmbh | A method of depositing a tin layer on a metal substrate and a use of a structure comprising a nickel/phosphorous alloy underlayer and said tin layer with said method |
| CN114232030B (en) * | 2021-12-23 | 2023-04-18 | 广东鑫菱环境科技有限公司 | PCB methanesulfonic acid tin stripping waste liquid recycling method |
| WO2024116456A1 (en) * | 2022-11-28 | 2024-06-06 | 株式会社村田製作所 | Method and device for regenerating plating composition |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1527576A (en) * | 1923-02-19 | 1925-02-24 | Wheeling Steel & Iron Company | Process of coating conducting materials with tin |
| US3784455A (en) * | 1971-12-28 | 1974-01-08 | Western Electric Co | Methods of electrolytic regenerative etching and metal recovery |
| DE2401719B2 (en) * | 1974-01-15 | 1978-01-19 | Vereinigte Aluminium Werke Ag, 5300 Bonn | METHOD FOR REGENERATING AND INCREASING THE SERVICE LIFE OF TIN-CONTAINING METAL SALT SOLUTIONS USED FOR THE ELECTROLYTIC COLORING OF ANODISED ALUMINUM UNDER THE ACTION OF AC |
| JPS5226315A (en) * | 1975-08-25 | 1977-02-26 | Fuji Photo Film Co Ltd | Process for the recovery of silver from fixer |
| DE2742718C2 (en) * | 1977-09-22 | 1984-04-19 | ESTEL HOOGOVENS B.V., 1970 Ijmuiden | Method and device for regenerating a tin-plating electrolyte |
| US4432844A (en) * | 1982-01-28 | 1984-02-21 | Fujisash Company | Process for regeneration of electrolyte containing tin salts by reducing the same |
| US4715894A (en) * | 1985-08-29 | 1987-12-29 | Techno Instruments Investments 1983 Ltd. | Use of immersion tin and tin alloys as a bonding medium for multilayer circuits |
| DE3634710A1 (en) * | 1986-10-11 | 1988-04-21 | Ver Glaswerke Gmbh | DEVICE FOR VACUUM COATING A GLASS DISC BY REACTIVE CATHODAL SPRAYING |
| CA2083196C (en) * | 1991-11-27 | 1998-02-17 | Randal D. King | Process for extending the life of a displacement plating bath |
| JPH06256999A (en) * | 1993-03-05 | 1994-09-13 | Kawasaki Steel Corp | Method for recovering and regenerating tin plating liquid |
| US6280596B1 (en) * | 1995-05-23 | 2001-08-28 | Weirton Steel Corporation | Electrolytic tinplating of steel substrate and apparatus |
| US5705048A (en) * | 1996-03-27 | 1998-01-06 | Oxley Research, Inc. | Apparatus and a process for regenerating a CUCl2 etchant |
| DE19719020A1 (en) * | 1997-05-07 | 1998-11-12 | Km Europa Metal Ag | Method and device for regenerating tinning solutions |
| US6251255B1 (en) * | 1998-12-22 | 2001-06-26 | Precision Process Equipment, Inc. | Apparatus and method for electroplating tin with insoluble anodes |
| JP3455709B2 (en) * | 1999-04-06 | 2003-10-14 | 株式会社大和化成研究所 | Plating method and plating solution precursor used for it |
-
2001
- 2001-07-03 DE DE10132478A patent/DE10132478C1/en not_active Expired - Fee Related
-
2002
- 2002-06-17 KR KR1020037017284A patent/KR100827259B1/en active IP Right Grant
- 2002-06-17 AT AT02754692T patent/ATE289633T1/en active
- 2002-06-17 DE DE60203050T patent/DE60203050T2/en not_active Expired - Lifetime
- 2002-06-17 BR BRPI0210829-1A patent/BR0210829B1/en not_active IP Right Cessation
- 2002-06-17 EP EP02754692A patent/EP1427869B1/en not_active Expired - Lifetime
- 2002-06-17 US US10/494,217 patent/US20040245108A1/en not_active Abandoned
- 2002-06-17 MX MXPA03011772A patent/MXPA03011772A/en active IP Right Grant
- 2002-06-17 ES ES02754692T patent/ES2236552T3/en not_active Expired - Lifetime
- 2002-06-17 WO PCT/EP2002/006654 patent/WO2003004725A2/en active IP Right Grant
- 2002-06-17 AU AU2002321069A patent/AU2002321069A1/en not_active Abandoned
- 2002-06-17 CA CA002450258A patent/CA2450258A1/en not_active Abandoned
- 2002-06-17 CN CNB028135822A patent/CN1232677C/en not_active Expired - Lifetime
- 2002-06-17 JP JP2003510478A patent/JP4157838B2/en not_active Expired - Lifetime
- 2002-06-21 TW TW091113655A patent/TWI279456B/en not_active IP Right Cessation
- 2002-06-26 MY MYPI20022395A patent/MY130423A/en unknown
-
2004
- 2004-08-03 HK HK04105703A patent/HK1062926A1/en not_active IP Right Cessation
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102586851A (en) * | 2011-01-06 | 2012-07-18 | 宝山钢铁股份有限公司 | Electrolytic method for relieving and reducing tin sludge generated in tin plating solution |
| CN102586851B (en) * | 2011-01-06 | 2015-03-04 | 宝山钢铁股份有限公司 | Electrolytic method for relieving and reducing tin sludge generated in tin plating solution |
| CN106811773A (en) * | 2015-05-12 | 2017-06-09 | 江苏理工学院 | Supercritical composite electroforming system recycling device |
| CN106811773B (en) * | 2015-05-12 | 2018-06-08 | 江苏理工学院 | Supercritical composite electroforming system recycling device |
| CN106011810A (en) * | 2016-06-02 | 2016-10-12 | 深圳市创智成功科技有限公司 | Removing process of tetravalent tin in chemical tin plating liquid of copper substrate |
| CN106011810B (en) * | 2016-06-02 | 2019-01-11 | 东莞市智源电子科技有限公司 | Stannic removal technique in the chemical tinning solution of Copper base material |
| CN110387540A (en) * | 2019-08-30 | 2019-10-29 | 江苏上达电子有限公司 | Stannous replenishment system and method in a kind of tin dissolving slot |
| CN111676470A (en) * | 2020-05-29 | 2020-09-18 | 广东天承科技有限公司 | Simple and soluble high-valence tin reduction method |
| CN116288292A (en) * | 2023-03-20 | 2023-06-23 | 聂柱根 | Chemical tin liquid tin reduction regeneration copper removal device |
Also Published As
| Publication number | Publication date |
|---|---|
| DE10132478C1 (en) | 2003-04-30 |
| KR100827259B1 (en) | 2008-05-07 |
| HK1062926A1 (en) | 2004-12-03 |
| WO2003004725A2 (en) | 2003-01-16 |
| EP1427869B1 (en) | 2005-02-23 |
| ATE289633T1 (en) | 2005-03-15 |
| US20040245108A1 (en) | 2004-12-09 |
| DE60203050D1 (en) | 2005-03-31 |
| MY130423A (en) | 2007-06-29 |
| DE60203050T2 (en) | 2006-02-23 |
| BR0210829B1 (en) | 2011-07-26 |
| JP4157838B2 (en) | 2008-10-01 |
| CN1232677C (en) | 2005-12-21 |
| AU2002321069A1 (en) | 2003-01-21 |
| WO2003004725A3 (en) | 2004-04-15 |
| MXPA03011772A (en) | 2004-04-02 |
| CA2450258A1 (en) | 2003-01-16 |
| TWI279456B (en) | 2007-04-21 |
| KR20040030725A (en) | 2004-04-09 |
| ES2236552T3 (en) | 2005-07-16 |
| JP2004534151A (en) | 2004-11-11 |
| BR0210829A (en) | 2005-05-03 |
| EP1427869A2 (en) | 2004-06-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1524132A (en) | Regeneration method for a plating solution | |
| JP3455709B2 (en) | Plating method and plating solution precursor used for it | |
| JP4551994B2 (en) | Method for recovering tin, tin alloy or lead alloy from printed circuit board | |
| KR100292944B1 (en) | How to substitute plating metal surface with support metal | |
| US5217751A (en) | Stabilized spray displacement plating process | |
| EP0088852B1 (en) | A process for regenerating electroless plating bath and a regenerating apparatus of electroless plating bath | |
| CN1626703A (en) | Electrolytic copper-stripping liquid and electrolytic stripping method | |
| JPH05222540A (en) | Method for prolonging life of replacement plating bath | |
| CN111188070A (en) | Manufacturing method for electroplating nickel, silver and gold on IC packaging board | |
| EP2594662B1 (en) | Aqueous composition for etching of copper and copper alloys | |
| CN1802456A (en) | Method for regenerating etching solutions containing iron for the use in etching or pickling copper or copper alloys and an apparatus for carrying out said method | |
| CN113463143A (en) | Electrochemical copper plating method based on full addition method | |
| CN1637174A (en) | Electrolytic stripping method | |
| EP1807549B1 (en) | Method for coating substrates containing antimony compounds with tin and tin alloys | |
| CA1136084A (en) | Electrolytic metal deposition with addition of particulate metal sulphate | |
| CN1266314C (en) | Improvement of adhesive property and compounding method for direct metalization | |
| CN110129799A (en) | Recycling method of tin stripping waste liquid based on sulfuric acid-ferric salt system | |
| KR101049236B1 (en) | Electroless Plating Method Using Palladium | |
| JPH0236677B2 (en) | ||
| JP4462851B2 (en) | Manufacturing method of conductive member | |
| CZ281606B6 (en) | Electrolytically recoverable etching solution | |
| JP2007046092A (en) | Apparatus and method for plating copper on sheet-shaped workpiece | |
| KR100710481B1 (en) | Composition for stripping tin and stripping method using the same | |
| CN105463544A (en) | Electroplating method for iron-made frame | |
| CA2193007C (en) | Process for extending the life of a displacement plating bath |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20051221 |