Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D21/00—Processes for servicing or operating cells for electrolytic coating
  • C25D21/12—Process control or regulation
  • C25D21/14—Controlled addition of electrolyte components
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S205/00—Electrolysis: processes, compositions used therein, and methods of preparing the compositions
  • Y10S205/92—Electrolytic coating of circuit board or printed circuit, other than selected area coating

Definitions

• the invention relates to a method and a device for the electrolytic deposition of uniform metal layers, preferably made of copper, with certain physical-mechanical properties.
• the electrolytic metallization for example with copper, of workpieces which are at least superficially electrically conductive has been known for a long time.
• the workpieces to be coated are switched as a cathode and brought into contact with the electrolytic deposition solution together with anodes.
• an electrical current flow is generated between the anode and the cathode.
• Anodes made of the metal that is deposited from the deposition solution are usually used.
• the amount of metal deposited from the solution is returned to the deposition solution by dissolution at the anodes.
• SPARE BLADE for a given charge throughput is approximately the same. This method is simple to carry out, since at least in the case of copper only sporadic measurement and control of the metal ion concentrations of the deposition solution is required.
• German patent specification DD 215 589 B5 describes a process for electrolytic metal deposition using insoluble metal anodes, in which reversibly electrochemically convertible substances are added to the deposition solution, which are added to the anodes by intensive forced convection with the deposition solution Separation device transported, there converted electrochemically by the electrolysis current, after its conversion by means of intensive forced convection is conducted from the anodes into a regeneration space, in the regeneration space on the regeneration metal located in it with simultaneous electroless metal dissolution of the regeneration metal in its initial state, and is returned electrochemically in this initial state by means of intensive forced convection to the separating device.
• This method avoids the disadvantages indicated when using insoluble anodes. Instead of the corrosive gases, the substances added to the deposition solution are oxidized at the anode, so that the anodes are not attacked.
• the dissolution of the metal in the regeneration room is independent of the process of metal deposition on the material to be treated.
• the concentration of the metal ions to be deposited is therefore regulated by the effective metal surface in the regeneration space and by the flow rate in the circuit. If there is a lack of metal ions, the effective metal surface and / or the flow rate from the deposition space to the regeneration space is increased, or correspondingly reduced if the metal ions are excess.
• This method therefore presupposes that a high concentration of the reversibly electrochemically convertible substance is contained in the deposition solution. This means that the oxidized compounds of the additives (redox system) at the cathode are reduced again, so that the current efficiency is reduced.
• German patent application DE 31 10 320 AI describes a method for cation reduction by anode-assisted electrolysis of cations in the cathode compartment of a cell, the anode compartment containing iron (II) ions as a reducing agent and the anodes relative to that surrounding the anodes Anolytes are moved.
• German patent application DE 31 00 635 A1 describes a method and a device for supplementing a plating solution with a metal to be deposited in a plating device.
• the metal to be struck is provided in a plating solution accommodated in a plating container and a supply of the metal to be deposited is provided within an enclosed space, the gases generated in the plating container as the plating process progresses are passed together with the plating solution into the enclosed space and there to the metal supply whose dissolution is applied and then the dissolved metal supply is added back to the plating solution in the plating tank.
• the device required to carry out the method is very complex since, among other things, it must be gas-tight.
• the methods mentioned have the disadvantage that the deposition solutions to be regenerated do not contain any additive bonds, which, however, are usually required to control the physical and mechanical properties of the metal layers to be deposited. These substances are mainly organic substances.
• the publication DD 261 613 A1 describes a process for the electrolytic copper deposition from acidic electrolytes with a dimensionally stable anode using certain additives for producing copper layers with defined physical-mechanical properties, the deposition electrolyte also reversing the aforementioned electrochemically contains implementable additives.
• the present invention is therefore based on the problem of avoiding the disadvantages of the methods and arrangements according to the prior art and of an economical method and the device suitable for this purpose for the electrolytic deposition of metal layers, in particular of copper. to be found, wherein the metal layers deposited by the method and by means of the device have predetermined physical-mechanical properties by adding additive bonds to the deposition solution to control the metal layer properties and the metal layer properties do not change disadvantageously even after a long deposition time. Furthermore, the metal layer thicknesses should be almost the same at all points on the surface of the material to be treated and deposition with a high current yield should be possible.
• Insoluble, dimensionally stable anodes are used to achieve sufficiently uniform layer thicknesses on the surface of the material to be treated.
• a metal ion generator is used which contains parts of the metal to be deposited are.
• the deposition solution contains compounds of an electrochemically reversible redox system.
• the oxidizing compounds of the redox system forming.
• the solution is then passed through the metal ion generator, the oxidizing compounds reacting with the metal parts to form metal ions.
• the oxidizing compounds of the redox system are converted into the reduced form.
• the formation of the metal ions keeps the total concentration of the metal ion concentration contained in the deposition solution constant. From the metal ion generator, the deposition solution returns to the electrolyte space which is in contact with the cathodes and anodes .
• the solution also contains additive bonds for controlling the physical-mechanical layer properties.
• means are provided according to the invention with which the concentration of the oxidizing compounds of the redox system in the immediate vicinity of the cathode can be minimized, preferably to a value below about 0.015 mol / liter.
• the additive bonds can be decomposed by the oxidizing compounds of the redox system. On the one hand, this would reduce the concentration of additive compounds in an uncontrolled manner. Since the determination of the concentration of these compounds is generally very complex, but the content of the compounds has a very sensitive effect on the physico-mechanical properties of the layers, only layers with fluctuating properties could inevitably be deposited, since a sufficiently fast-acting one and precise analysis technology is not available for such requirements.
• the agents according to the invention with which the concentration of the oxidizing compounds in the vicinity of the cathode can be minimized, preferably to a value below about 0.015 mol / liter, are shown below:
• the total amount of the compounds of the redox system added to the deposition solution is such that practically the entire amount of the oxidizing compounds of the redox system fed to the metal ion generator with the deposition solution is required to dissolve the metal parts there with the formation of metal ions.
• the amount of metal ions supplied by the dissolution must just add to the proportion that is lost to the deposition solution by deposition. To maintain the metal ion concentration and to completely reduce the amount of oxidizing agent introduced into the metal ion generator
• a minimum size of the metal part surface in the metal ion generator is therefore required for connections.
• This surface can be enlarged as desired, but in particular it does not need to be variable. Refilling the metal parts into the metal ion generator in any amounts above the minimum amount mentioned is thus technically simple.
• the spatial distance between the anodes and the metal ion generator must be small, the connections for transferring the deposition solution flowing to the anodes to the metal ion generator and from the metal ion generator back into the electrolyte space must be short. This ensures that the sales because the time of the oxidizing compounds in the electrolyte space is short. As a result of the rapid transfer of the deposition solution containing the oxidizing compounds into the metal ion generator, these compounds only have a short life span until they are converted into the reduced compounds of the redox system.
• the flow rate of the deposition solution must be as high as possible, especially when transferring from the anodes to the metal ion generator.
• means for blowing air oxygen are provided in the lower region of the generator.
• Another possibility for supplementing the metal ions removed from the deposition solution by deposition is basically to add the metal ions to the deposition solution in the form of their compounds or salts.
• concentration of the anionic portions of the compounds or salts which are necessarily added with the metal ions increases continuously due to the continuous addition of the compounds, so that the solution is discarded after a certain time got to.
• the time until the solution is discarded can be quite long.
• a possible decomposition of the additive bonds is avoided or at least significantly reduced by the reduction in the service life of the oxidizing compounds of the redox system formed at the anode and the minimization of the concentration of the compounds.
• the metal ion concentration in the electrolyte compartment can also be influenced by a special circulation of the deposition solution.
• the reduced compounds of the redox system are located in the cathode compartment and are electrochemically converted to the oxidizing compounds at the anodes by the electrolysis current. The amount of oxidizing
• the other part of this solution which does not contain the oxidizing compounds, is passed directly into the metal ion generator.
• separate processes for the deposition solution, which are located in the vicinity of the cathode are provided.
• the solution branched off via the drains reaches the metal ion generator through suitable pipes.
• the surface of the metal to be dissolved is in turn dimensioned so sufficiently that all the oxidizing compounds introduced into the metal ion generator can be converted electrochemically.
• the flow conditions in the electrolyte chamber are to be designed such that, on the one hand, a flow of the deposition solution is directed from the cathode to the anode, and on the other hand, however, the deposition solution initially flows directly onto the cathode.
• the latter is necessary in order to be able to economically produce uniform layers with sufficiently high current densities and with specified physical-mechanical properties.
• the arrangement preferred for carrying out the method according to the invention comprises, in addition to the cathodes, insoluble, preferably perforated, dimensionally stable anodes, devices for the flow against the cathodes and anodes with the separation solution (nozzle sticks, surge nozzles), means for deflecting the flow to the anodes and Connection lines for transferring the deposition solution flowed to the anode to the metal ion generator and for transferring the deposition solution exiting the metal ion generator back into the electrolyte compartment.
• means for extracting the deposition solution can also be provided in order to increase the flow rate when the deposition solution is transferred from the anodes to the metal ion generator.
• the electrolyte space can also be divided into several compartments by ion-permeable partition walls (ion exchangers, diaphragms).
• the metal ion generator is preferably a tubular device which can be filled from above and which has a bottom in the lower region and at least one pipe socket with side openings for the electrolyte inflow and an overflow which opens into an electrolyte container in the upper region is.
• inclined, preferably perforated plates are attached inside the metal ion generator.
• the method is preferably suitable for the metallization of printed circuit boards.
• copper in particular is deposited on the surfaces and lateral surfaces of the boreholes.
• the basic composition of a copper bath can vary within relatively wide limits when using the method according to the invention.
• An aqueous solution of the following composition is generally used:
• Sulfuric acid conc. 50-350 g / liter, preferably 180-280 g / liter or
• copper sulfate instead of copper sulfate, other copper salts can also be used, at least in part.
• Some or all of the sulfuric acid can also be replaced by fluoroboric acid, methanesulfonic acid or other acids.
• the chloride ions are used as alkali chloride, for example sodium chloride, or in the form of hydrochloric acid, p.A. admitted.
• the addition of sodium chloride can be omitted in whole or in part if halogen ions are already present in the additives.
• the effective form is formed from iron (II) sulfate heptahydrate
• Fe + / Fe 3+ redox system It is excellently suitable for the regeneration of the copper ions in aqueous acidic copper baths.
• other water-soluble iron salts in particular iron (III) sulfate nonahydrate, can also be used, provided that the salts do not contain any biodegradable (hard) complexing agents in the compound, since the latter cause problems in the rinsing water disposal (for example iron ammonium ⁇ alum).
• compounds of the elements titanium, cerium, vanadium, manganese, chromium and others are also suitable as further redox systems.
• Compounds which can be used are in particular titanyl sulfuric acid, cerium (IV) sulfate, sodium metavanadate, manganese (II) sulfate and sodium chromate. Combinations of the aforementioned redox systems can also be used for special applications.
• the method according to the invention can otherwise be used known and proven elements of electrolytic metal deposition are retained. For example, customary brighteners, levelers and wetting agents can be added to the deposition solution. In order to obtain copper precipitates with specified physical-mechanical properties, at least one water-soluble sulfur compound and one oxygen-containing, high-molecular compound are added. Additive compounds, such as nitrogen-containing sulfur compounds, polymeric nitrogen compounds and / or polymeric phenazonium compounds, can also be used.
• the additive bonds are contained within the following concentration ranges in the deposition solution:
• Thiourea derivatives and / or polymeric phenazonium compounds and / or polymeric nitrogen compounds as additive compounds are used in the following concentrations:
• the deposition solution is moved by blowing air into the electrolyte space. Additional air flow to the anode and / or the cathode increases the convection in the area of the respective surfaces. This optimizes the mass transport in the vicinity of the cathode or anode, so that greater current densities can be achieved. Aggressive oxidizing agents, such as oxygen and chlorine, which may be formed in a small amount, are thereby removed from the anodes. Movement of the anodes and cathodes also improves the mass transfer on the respective surfaces. This ensures a constant diffusion-controlled deposition. The movements can take place horizontally, vertically, in a uniformly lateral movement and / or by vibration. A combination with the air flow is particularly effective.
• Inert material is used for the anodes.
• Anode materials that are chemically and electrochemically stable with respect to the deposition solution and the redox system used are suitable, for example titanium or tantalum as the base material, coated with platinum, iridium, ruthenium or their oxides or mixed oxides. Titanium anodes with an iridium oxide surface, which was irradiated with spherical bodies and thereby compressed free of pores, were sufficiently stable and therefore had a long service life. Due to the anodic current density or the voltage between the cathode and
• the anode-controlled anode potential determines the amount of the aggressive reaction products formed at the anode. Below 2 A / dm 2 , their formation rate is very small. In order not to exceed this value, large effective anode surfaces are sought. Therefore, in the case of limited spatial dimensions, perforated anodes, for example anode meshes or expanded metal, with a corresponding coating are preferably used. This will take advantage of large effective surface area combined with the simultaneous possibility of intensive flow through the anodes with the deposition solution, so that any aggressive reaction products that may arise can be removed. Anode networks and / or expanded metal can additionally be used in several layers. As a result, the effective surface area is increased accordingly, so that the anodic current density is reduced for a given electroplating current.
• Metal is added in a separate container, the metal ion generator, through which the deposition solution flows.
• the metal ion generator contains metallic copper parts, for example in the form of pieces, spheres or pellets.
• the metallic copper used for regeneration does not need to contain phosphorus, but phosphorus does not interfere either.
• the composition of the anode material is of great importance: in this case, the copper anodes must contain about 0.05% phosphorus. Such materials are expensive and the addition of phosphorus causes residues in the electrolytic cell, which have to be removed by additional filtering.
• electrolytic copper including copper scrap
• the copper-coated printed circuit board waste such as occurs in large quantities in the production of printed circuit boards, can also be used for this purpose, provided that they do not contain other metals. Because of the adhesive bond between the two materials, these wastes, consisting of the polymeric base material and the applied copper layers, can only be disposed of in a conventional manner at high costs. After the useful dissolution of the copper of these wastes in a metal ion generator suitable for this purpose, it is possible to dispose of the base material according to type. Similarly, reject boards can also be used be used.
• Filters for separating mechanical and / or chemical residues can also be inserted into the circulation of the separation solution. However, their need is lower in comparison to electrolytic cells with soluble anodes, because the anode sludge which arises from the addition of phosphorus to the anodes does not arise.
• FIG. 4 Guidance of the separation solution, FIG. 4 - principle of a device with horizontal transport of the material to be treated, FIG. 5 - metal ion generator on a device for immersion treatment, FIG. 6 - metal ion generator on a device for horizontal transport of the Treatable goods.
• Fig. 1 the inventive method is shown using a schematic device.
• the electrolyte space 1 is located in the container 3.
• the metal ion generator 2 is constructed and arranged with respect to the container 3 in such a way that there are short distances in the supply of the deposition solution from the anodes 5 to the metal ion generator and from there back into the electrolyte space surrender.
• the metal ion generator is shown in two parts in the present case and is arranged in the vicinity of the insoluble anodes.
• this division into two is not mandatory.
• it can also be used as a one-piece unit on the side or be arranged below the bath tank.
• the copper parts 8 to be dissolved are introduced in bulk into the metal ion generator in order to allow the deposition solution to be easily passed through the generator. On the other hand, this must not fall below a minimum loading with copper parts.
• the pump 11 conveys the separation solution in the circuit through the arrangement. It is essential that the treatment material 6 connected as cathode, as indicated by the arrows 14, is flown with the deposition solution enriched with copper ions via nozzle assemblies or surge nozzles, which are not shown here. This ensures that the copper layers are deposited on the surfaces of the material to be treated with the required quality and speed. Furthermore, a further flow arises within the electrolyte space from the space 15 in the vicinity of the material to be treated in the direction of the space 16 in the vicinity of the anodes.
• the deposition solution which has flowed to the anodes passes through them when it is are perforated anodes and, with the progressive flow, reaches outlet 4, which leads into the metal ion generator. It is thereby achieved that a transport of anodically formed oxidizing compounds of the redox system (iron (III) ions) into the cathode space 15 is minimized. This in turn reduces the harmful decomposition of the additive bonds while at the same time increasing the cathodic current yield.
• the aim is to have the shortest possible connection with a high flow rate of the deposition solution to the metal ion generator.
• the minimum loading of the metal ion generator with copper parts ensures that the oxidizing compounds formed within the metal ion generator are completely are set and the concentration of these compounds at the output of the metal ion generator is reduced to a value of approximately zero.
• the reduced connections of the redox system do not contribute to the decomposition of the additive bonds.
• the anodes are subject to a lower electrolyte exchange for a given total circulation capacity.
• the aggressive gases which may arise at the anodes are removed correspondingly more slowly, so that the corrosion of the anodes increases on the one hand, but is limited on the other hand by the following measures:
• FIG. 1 A further device according to the invention is shown in FIG. On the one hand, this differs from the arrangement according to FIG. 1 by a modified guidance of the deposition solution within the electrolyte space, which consists of a in the There is space 15 in the vicinity of the material to be treated, the cathode space, and spaces 16 in the vicinity of the anodes, the anode spaces. In the drawing, these spaces are separated by the dashed lines 17.
• the deposition solution which was enriched with copper ions in the reduction of Fe (III) to Fe (II) ions in the metal ion generator 2, flows separately into each room and passes through nozzle sticks or surge nozzles, not shown, accordingly Arrows 12 and 14 to the anodes 5 or to the cathodic material 6.
• the ion concentration in the cathode compartment is kept small, which is directly connected to the inlet to the metal ion generator 2, so that there is a short route from the anode compartment to the metal ion generator.
• the transport routes from the cathode compartment via the outlet 18 to the generators can be long, since there are no harmful interactions between the reduced connection contained in the deposition solution located in the cathode compartment and the additive connections.
• these spaces can be separated along the lines 17 by an ion-permeable partition (diaphragm), which in turn is not chemically changed by the deposition solution.
• the partitions are permeable to the separation solution only to a very small extent or not at all, so that they may only allow a slow compensation of different hydrostatic pressures in rooms 15 and 16.
• Polypropylene fabrics or other membranes with a permeability for metal ions and their corresponding counterions are suitable, for example.
• the deposition solution located in the anode compartment, which contains the Fe (III) ions formed there, is in turn transferred to the metal ion generator by the shortest route and enriched again with copper to form the Fe (II) ions.
• a state of equilibrium is set between the copper dissolution in the metal ion generator and the copper deposition on the material to be treated.
• FIG. 3 shows a further embodiment of the invention with a two-part metal ion generator.
• the deposition solution enriched with copper ions in the metal ion generator 2 is only introduced into the cathode space 15.
• This solution also contains only Fe (II) ions and no Fe (III) ions.
• the deposition solution is conducted serially from the cathode chamber 15 to the anode chamber 16.
• the Fe (II) ions formed in the metal ion generator therefore reach the anode compartment after passing through the cathode compartment with the deposition solution via a pump 19.
• the deposition solution is fed into the cathode space via a further pump 11.
• this serial guidance of the deposition solution allows the deposition solution withdrawn from the cathode compartment to be divided.
• part of the solution is fed directly into the metal ion generator via the lines 43 shown in broken lines. directs.
• This subset contains almost no oxidizing compounds of the redox system, so that the admixture of this portion into the solution stream, which comes from the anode compartment into the metal ion generator, reduces the copper dissolution rate.
• FIGS. 1 to 3 the introduction of the deposition solution enriched with copper ions into the container 3 is exemplified from below and into the metal ion generator 2 from above.
• the discharges through processes 4 and 18 from the container 3 above and from the metal ion generator 2 are shown below. Cycles of the deposition solution in other directions are also possible, such as the introduction of the solution into the metal ion generator from below.
• Another embodiment of the invention in particular for the electrolytic metallization of plate-like items to be treated, preferably of printed circuit boards, in the horizontal direction
• the section shown in the side view consists of the electrolytic part 20 and one below it shown metal ion generator 21 with copper filling.
• the electrolytic part 20 consists of several electrolytic individual cells. Four of these individual cells are shown in FIG. 4 with the reference numbers 22, 40, 41, 42, each with an insoluble anode 23 for the upper side and for the lower side of the material to be treated 24.
• the material to be treated is electrical with a rectifier (not shown) tric connected and cathodically polarized. It is transported through the system in the direction of arrow 25 by means of rollers or disks 26.
• the transport elements 26 are evenly distributed along the entire system. To simplify the illustration, these are only shown at the beginning and at the end of the transport route. There are also evenly distributed surge nozzles or flood pipes 27, 39 in the electrolytic cells. These correspond to the nozzle assemblies already mentioned above.
• the flood tubes 27, 39 are supplied with a separation solution coming from the metal ion generator 21 by means of pumps 29 via the pipes 28.
• the deposition solution flows to the surfaces of the material to be treated 24 through the outlet openings of the flood pipes or surge nozzles. Copper ions are reduced to metallic copper and deposited on the material to be treated as a metallic layer, and the iron (II) ions which are also present are removed with the flowing electrolytes promoted in the direction of the anodes 23.
• Various measures are provided to avoid backflow from the anodes to the cathodes, the implementation of which is shown schematically in FIG.
• the separation solution enriched with copper becomes the inflow to the
• Cathode material to be treated
• the solution stream is then deflected from the plate-shaped material to be treated in such a way that, as indicated by the arrows 30, it moves in the direction of the anodes.
• the solution passes through them and then reaches the metal ion generator again via suction pipes 31 and pipes 32.
• the anodes can consist, for example, of expanded metal or nets.
• Culverts 33 support the flow-through process.
• guide walls 34 which extend in the direction of the material to be treated, can be attached to the suction pipes.
• the remaining gap 35 between the guide walls and the material to be treated can be a few millimeters. From a fluidic point of view, this forms almost closed electrolytic cells with favorable flow conditions.
• the flood pipes 27 can also be provided with guide walls 36 in order to prevent further possible turbulence.
• the removal of the deposition solution from the anode compartment via the suction pipes 31 into the metal ion generator 21 can be done in the shortest possible way in order to keep the life of the iron (III) ions as short as possible. Therefore, the metal ion generator 21 is also arranged as close as possible to the electrolytic part 20. This results in short connection paths and short transport times.
• the construction principle can advantageously also be chosen so that the parts 20 and 21 form an overall system.
• Several flood tubes 27 are each fed by a pump 29, as in FIG. _-- l p
• gur 4 is shown.
• a single pump can also be used. This would lead to longer connection paths between the flood tubes 27, 39 and the metal ion generator 21.
• the separation solution in these connecting lines contains practically no oxidizing compounds of the redox system. The protection of additive bonds is also guaranteed in this area.
• the electroplating system is shown in FIG. 4 in a side view.
• the parts shown (anodes, pipes) extend langge ⁇ stretched in the depth of the drawing in, ie transversely to the transport direction over "the treated ⁇
• the splashing in elektri ⁇ field between the anode and cathode located parts, such as the flow tubes 27, made of electrically Their electrical dimming effect is not disturbing here because the material to be treated moves slowly through the system and is thus continuously exposed to the different electrical fields.
• FIG. 5 shows an arrangement according to the invention with two metal ion generators 44, an electrolyte compartment 1 and two further electrolyte containers 45.
• This arrangement is operated in the immersion process.
• the cell is constructed symmetrically for galvanizing the front and back of the material 6 to be treated.
• the two metal ion generators 44 shown in the figure and the electrolyte containers 45 can each also be provided individually and in this case can be assigned to both sides of the material to be treated.
• the metal ion generator 44 consists of a preferably round tubular body 46 with an upper opening 47. All of the materials used for this are resistant to the deposition solution and the additives contained in the solution.
• At least one pipe socket 49 projects through the bottom 48 of the metal ion generator into the interior of the metal ion generator. This pipe socket has lateral openings 50. These form a sieve, which on the one hand prevents metallic copper from penetrating into the pipe system and on the other others allow the deposition solution to pass into the metal ion generator.
• a small protruding roof closes the pipe socket at the top. The roof also keeps the lateral openings 50 free of fine copper granules located in this area of the metal ion generator.
• a mixing and collecting chamber 51 is located below the bottom.
• the chamber After opening the base plate 52, the chamber is accessible for cleaning purposes.
• air containing oxidizing oxygen can also be blown into the metal ion generator via lines 56.
• the chamber 51 also serves as a mixing chamber. The separation solution and possibly air get through the holes 50 of the pipe socket 49 into the interior of the metal ion generator. In the lower area of the generator there is predominantly fine copper granulate, which was created by dissolving the metallic copper. It has a very large specific
• the overflow 54 bends downwards in such a way that copper granules 53 which slide down from above cannot lead to the generator being blocked.
• the copper solution that flows through the overflow 54 into the electrolyte container 45 contains practically no Fe (III) ions.
• Such overdimensioning of the regeneration unit thus ensures that the attack of the Fe (III) ions on the additive bonds of the deposition solution has ended in the middle area of the generator.
• the metal ion generator is filled and refilled with metallic copper 53 from above through the funnel-shaped opening 47, for example. This can be closed with a lid.
• the "region above _des overflow 54 by any plating is located, is used to Bevor ⁇ consultancy of metallic copper to be dissolved rator in the metal ion generation.
• the filling rate and refilling can be done manually '.
• the arrangement is due to the Drucklosig
• the capacity at the filling opening 47 and the vertical or inclined installation is excellently suitable for automating the filling process. This can be done continuously or discontinuously.
• Conveyor belts or vibratory conveyors, not shown here, from conveyor technology transport the metallic copper into the openings 47 of the generators.
• An advantage of the invention is that copper parts of different geometric shapes can be dissolved in the metal ion generator. However, different shapes have different bulk behavior. Additional individual measures are possible to maintain the permeability of the bed for the deposition solution and to ensure a sufficiently large copper surface that is accessible to the solution:
• Plates 55 inclined downwards in the interior of the generator prevent excessive compression of the copper in the lower region.
• the plates are provided with openings, the dimensions of which are adapted to the size of the filled-in metallic copper parts.
• the breakthroughs are going from plate to Plate chosen smaller according to the copper resolution from top to bottom.
• the dimensions of the plates can increase from top to bottom.
• the angles of the inclined positions can also be adapted to the conditions of the copper pieces filled in the metal ion generator.
• Tilting the metal ion generator itself can do the same.
• a copper-dissolving substance in this case oxygen, is additionally introduced through the air injection 56 into the lower region of the metal ion generator or into the mixing and collecting chamber 51.
• the associated swirling of the copper granules in the metal ion generator increases the reduction in Fe (III) ions and the copper dissolution.
• the permeability for the deposition solution through the copper parts is increased.
• the vibrating movement can preferably be derived from an oscillating conveyor, with which the automatic filling is also provided. All the measures described above for trouble-free continuous operation of the metal ion generator can also be combined with one another.
• the electrolyte containers 45, 67 shown in FIGS. 5 and 6 serve to reduce the dependence of the flow of the deposition solution on the material to be treated 6, 69 on the flow through the metal ion generator 44, 66. This has the advantage that the amount of the separation solution and its speed can be individually adjusted in both circuits. These processes are described below with reference to FIG. 5.
• the separation solution is conveyed from the electrolyte container 45 into the electrolyte space 1 by means of a pump 57.
• the solution flows through the flood tubes 58 arranged there to the material 6 to be treated and from the flood tubes 59 to the liquid-permeable insoluble anodes 5.
• the solution stream is divided between the flood tubes 58 and 59 by here adjustable valves, not shown.
• the deposition solution flows out of the cathode chamber 15 via the outlet 18 through pipes 60 and the outlet 61 back into the electrolyte container 45.
• suction tubes 62 Immediately behind the anodes 5 are suction tubes 62, through which the deposition solution enriched with Fe (III) ions is sucked off by means of the pump 63 and conveyed into the metal ion generator at high speed. From there, the solution enriched with Fe (II) and Cu (II) ions then returns to the electrolyte container 45.
• the distribution of the currents to the flood tubes 58 and 59 is set so that there is an excess in the cathode space 15. This balances out towards the anode compartment 16. If the two rooms are separated by a partition 17, as shown in FIG. 5, at least one opening 64 in the partition ensures that the separation solutions in both rooms can be balanced in the direction of the arrow. To avoid mixing of the solutions in the electrolyte chamber 1 and convective transport of Fe (III) ions from the anode to the cathode chamber, it is therefore only necessary to ensure that a higher hydrostatic pressure in the deposition solution in the cathode chamber 15 compared to that in the Anode space 16 exists. This is a ⁇ appropriate adjustment of the partial flows through the flow tube 58 and through the flood pipes 59 of the pump 57 run Kreis ⁇ ensured. In addition, the circuits of pumps 57 and 63 are independent of one another.
• FIG. 6 A further embodiment of the device according to the invention The procedure for carrying out the method is shown in FIG. 6.
• This is a horizontal printed circuit board electroplating system shown in cross section.
• the figure shows the metal ion generator 66, an electrolyte container and a galvanizing cell 68.
• the circuit board 69 to be metallized is gripped in the arrangement of clamps 70 and conveyed horizontally through the system.
• the contacting of the circuit board with the negative pole of a rectifier, not shown, also takes place via these brackets. In another embodiment, the contact could also be made via contact wheels.
• a pump 71 conveys the deposition solution via flood pipes 72, 73 to the printed circuit boards and to the insoluble perforated anodes 74.
• the deposition solution is returned from the cathode compartment to the electrolyte container 67 via outlets 75.
• the pump 86 conveys the deposition solution enriched with Fe (III) ions through suction pipes 76 into the metal ion generator at high speed.
• An outlet 77 which is designed as an overflow for level control, ensures that excess deposition solution from the upper region of the anode space also reaches the circuit to the metal ion generator 66 and not the electrolyte container 67.
• the metal ion generator is constructed in the manner described with reference to FIG. 5.
• the separating solution returns to the electrolyte container 67 via the overflow 78.
• Partition walls 80 are also provided between the anode and cathode spaces. Openings 81 in these partition walls also ensure a compensation of the flows of the deposition solution from the cathode into the anode space. These flow directions are also set when there are no partition walls.
• Horizontal continuous systems, as shown in FIGS. 4 and 6, and vertical electroplating systems have dimensions of several meters in length of the electrolytic cells. Therefore, in practice, several rere metal ion generators arranged along the plant. This allows them to be installed in close proximity to the electro-lytic cell or a partial or complete interposition of the electrolytic cell, electrolyte container and metal ion generator.
• the clamps 70 are also metallized in the area of their contacts 82. This layer must be removed before the clips can be used again. This takes place in a known manner during the return of the clips to the beginning of the electroplating system.
• the returning brackets 83 pass through a separate compartment 84 which is connected to the deposition solution in the electrolytic cell 68.
• the clamps 83 are connected to the positive pole of a rectifier (not shown) via sliding contacts. The negative pole of this rectifier is connected to a cathode plate 85.
• the parameters for demetallization current and time are therefore set such that, for example, only 70% of the demetallization section is required to remove the metal layer.
• Fe 3+ ions are generated by the electrolysis current on the metallic and contacted parts of the clamps. These are located exactly where there may still be contactless copper deposits. You dissolve this copper without external current.
• a noticeable increase in Fe (III) ions in the electrolytic cell does not occur because only very small currents and areas are involved in comparison to the metallization of the material to be treated.
• the copper content in the deposition solution must be certain Limits are kept. This presupposes that the consumption rate and the rate of tracking copper ions correspond.
• the absorption capacity of the deposition solution can be measured at a wavelength of approximately 700 nm.
• the use of an ion-sensitive electrode has also proven successful.
• the measured variable obtained serves as the actual value of a controller, the manipulated variable of which is used to maintain the copper ion concentration in the respective described embodiments of the invention.
• a potential measurement can be carried out for analytically tracking the concentrations of the compounds of the redox system.
• a measuring cell is used, which is made up of a platinum electrode and a reference electrode.
• the respective concentration ratio can be determined by correspondingly calibrating the measured potential position with the concentration ratio of the oxidizing and the reduced compounds of the redox system for a given total concentration of the compounds.
• the measuring electrodes can be installed both in the anode and cathode compartments and in the pipes of the arrangement.
• a further measuring device can be provided in which the anode potential is measured with respect to a reference electrode.
• the anode is connected to the corresponding reference electrode via a potential measuring device.
• the continuous or discontinuous measurement-technical determination of further galvanotechnical parameters is expedient, such as the determination of the content of additive bonds by means of cyclic voltammetry. This means that temporary shifts in concentrations can occur after long breaks in operation. The knowledge of the current sizes can be used to incorrectly dose the supplements Avoid chemicals.
• a current yield of 84% was determined.
• the consumption was determined over 100 Ah / liter to:
• Example 1 The experiment of Example 1 was repeated in the arrangement shown in FIG. 3, the deposition solution being passed serially through the cathode and anode compartments. A current efficiency of 92% was achieved. The consumption, again averaged over 100 Ah / liter, was:
• the elongation at break improved to 20%.
• the coated printed circuit boards withstood a two-time solder shock test (10 seconds at 288 ° C. soldering temperature) without cracks in the area of the drill holes. The deposit was evenly shiny.
• Example 1 The experiment described in Example 1 was carried out in an electrolysis cell. The measures according to the invention were not discontinued, especially not the inflow of the cathodes and anodes according to the invention.
• Example 1 copper layers were deposited on printed circuit boards after copper had previously been deposited on the substrate from the solution over a longer period of time (2000 Ah / liter).
• circuit boards did not pass a double solder shock test (10 seconds at 288 ° C soldering temperature) without cracks. Uneven copper layers were also obtained. In Examples 1 to 3, copper layers with good to very good elongation could be deposited. The cathodic current yield and the consumption of the additive bonds which were added to the deposition solution to control the physical-mechanical layer properties were also satisfactory. The appearance of the copper layers was flawless and withstood the application tests.

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