Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/02—Electroplating of selected surface areas
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/22—Secondary treatment of printed circuits
  • H05K3/24—Reinforcing the conductive pattern
  • H05K3/241—Reinforcing the conductive pattern characterised by the electroplating method; means therefor, e.g. baths or apparatus
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/54—Electroplating of non-metallic surfaces
  • C25D5/56—Electroplating of non-metallic surfaces of plastics
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D7/00—Electroplating characterised by the article coated
  • C25D7/06—Wires; Strips; Foils
  • C25D7/0614—Strips or foils

Definitions

• the invention refers to a process for electroplating a work piece, which is coated with an electrically conducting or modified polymer.
• the invention shows apparatus for carrying out this process.
• electroplating For the targeted change of the surface, or of the surface structure, of two and three dimensional work pieces, electroplating, even in the case of non- metallic surfaces, is a process which corresponds to the state of the art and which often is used in practice.
• metallizing and complete contact formation of the base material is achieved by electroplating.
• the base material consists of an insulator where a large portion of the surface, which is to be electroplated, is coated with an electrically conducting or modified, polymer.
• this problem is solved by connecting the work piece in the first step of the process to a current source by multiple adjacent contact elements and coating with a continuous, thin metal layer except at the contact locations covered by the contact elements.
• the contact elements are removed in a second process step, and an unbroken, continuous coat is formed.
• This has the advantage that an electrical field is generated even with only a low current density, which is sufficient for electroplating the surface.
• the electrically conducting polymer coating is connected to the current source so that an almost uniform electrical field is generated covering the entire surface of the work piece to be electroplated.
• a thin metal layer is formed on the electrically conducting polymer coating of the work piece to be electroplated.
• This metal layer is unbroken except for the contact points covered by the contact elements.
• the contact elements are laid out on the surface to be electroplated in such a manner that the metal layer deposited in the first step of the process extends over the entire surface and forms a continuous metal coat. Due to the multitude of the contact elements used, the build-up of the metal coat requires J only a relatively short electroplating time. It is of advantage that despite the reduction of the current density the electroplating time does not increase. To the contrary, the process described by the invention presents the possibility to also reduce the electroplating time despite the reduced current density.
• the disadvantages of the processes known from the current state of the art represented by a destruction of the polymer coating, due to an excess of current density or due to an excess of electroplating time can be entirely avoided by the use of the process described by the invention.
• the surface area to be electroplated is charged with current through the metal coat formed in the first process step.
• a metal deposit now also forms at the contact points covered by the contact elements during the first process step, so that a unbroken metal coat forms over the entire surface of the work piece to be electroplated.
• this second electroplating step also only relatively low current densities as well as short electroplating times are required since the metal coat formed in the first process step covers the surface area, and thus a generally homogeneous electrical field is built also with low current density.
• the metallic coat represents a good electrical conductor with a low specific resistance.
• the second process step intended for the formation of an unbrokenly continuous metal coat can be carried out in accordance with the invention in such a manner that the contact points not yet covered after the completion of the first step are provided with a metal coating, so that in this manner the contact points still remaining open are "closed", and an unbroken metal coat is formed in the second process step.
• the second process step can also be carried out in such a manner that the metal coat formed in the first process step keeps growing so that an unbroken metal coat is formed which also covers the contact points.
• the second process step can also be carried out using a different electrolyte composition, for example.
• connection of the work piece to be coated is by multiple adjoining contact elements so that a generally homogeneous electrical field is built over the entire surface.
• the contact points covered up by the contact elements of the surface to be coated can then be closed by the formation of an unbroken metal coating in a second process step.
• the individual contact elements on the surface to be electroplated are placed lattice-like next to each other.
• both in the first process step in which the surface to be coated is connected to the current source over the contact elements and also in the second process step when the current supply takes place over the metal coating formed in the first process step an extensive, evenly formed electrical field extends over the entire surface area to be electroplated.
• the metal coat to be formed in the first process step by itself constitutes a continuous electrical conductor. It is therefore suggested that it is especially advantageous if neighboring contact elements are laid out equidistant.
• a contact element carrier is used for the contact element layout, which comprises several contact elements.
• a quick placement of the contact elements on the surface to be electroplated is achieved in this manner
• the use of a contact element carrier permits extensive automation of the process described in the invention.
• the contact element carrier preferably is designed in such a manner that it comprises multiple adjoining contact elements which can be moved from their relative position for adjustment purposes, whereby adjustment of the contact elements relative to each other as well as to the contact element carrier itself is possible.
• a frame with mounted contact elements is used as a contact element carrier.
• Such a frame-like contact element carrier is especially suitable for electroplating of 2-dimensional work pieces such as, for example, circuit boards.
• a frame is rectangular in shape while other geometric shapes are conceivable, depending on the type of application.
• Multiple contact elements are mounted on the frame which are placed either on all or on individual components forming the frame. For the connection of the surface to be electroplated to the current source, this is contacted by the elements of the frame-shaped contact element carrier.
• several frames can be placed next to each other or on either side of the work piece to be electroplated. It is especially attractive in the case of circuit boards, to metal-coat the basic raw circuit board on both sides in the course of one process step.
• a fixture with multiple contact elements is used as contract element carrier.
• a fixture of this type especially serves the connection of a 3 -dimensional work piece. This is inserted into a fixture designed for this purpose and connected to the current source over the contact elements attached to the fixture. In this manner it is made possible to unbrokenly electroplate even a geometrically complex work piece in one process step. It is self-evident, of course, that in addition to the design of the contact element carrier as a frame or as a fixture other forms are conceivable. The deciding factor is that the surface of the work piece to be electroplated can be covered area-wide by the contact element carrier with multiple contact elements.
• the contact elements are designed to be movable in their relative position on the one hand to each other, as well as to the contact element carrier on the other hand; and that they can be adjusted for contact with the work piece to be electroplated for connection to the current source, depending on the work piece geometry.
• a metallic grate is used as the contact element carrier.
• the metallic grate is especially suited to horizontal applications in continuous processing facilities.
• This metallic grate constitutes a complete electrical conductor so that its placement on the surface to be electroplated leads to the build-up of a general, homogeneous electrical field.
• a metallic coat can be formed which basically constitutes a negative of the grid.
• the areas of the surface to be electroplated not covered by the grid are covered with a metal layer.
• the grid can then be removed and a closed metal coating formed on the surface.
• the surface to be electroplated is contacted by the grid, and the work piece together with the grid is fed through the electrolyte.
• the grid simultaneously also serves as a conveyor.
• counter anodes are supplied by which the metal deposited from the metallic grid is loosened from the work piece.
• the thickness of the metal coat produced by the process can be specified. This can be adjusted, on the one hand by the dwell time of the work piece in the electrolyte, and by the connected current density on the other.
• Fig. 1 is a schematic of the first step of the process described by the invention for the manufacture of a circuit board in the vertical process.
• Fig. 2 is a schematic of the second step of the process described by the invention for the manufacture of a circuit board in the vertical process.
• Fig. 3 is a schematic of a grate serving as a contact element carrier.
• Fig. 4 is a schematic of the first step of the process described by the invention for the manufacture of a circuit board in the horizontal process.
• Fig. 5 is a schematic section of a contact element in accordance with a first application design.
• Fig. 6 is a schematic section of a contact element in accordance with a second application design.
• Fig. 1 shows the manufacture of a circuit board 1 in accordance with the process described in the invention.
• the first step of the process is shown.
• electrolyte 2 generally perpendicular to the electrolyte surface 3
• a base body 4 made of an insulator and coated with an electrically conducting or modified polymer layer is inserted. Due to the fact that the base body 4 is moved generally perpendicular to the electrolyte surface 3, this process may also be referred to as a vertical process.
• the base body 4 is connected to the current source 8 over multiple contact elements 5. This is achieved by a branching electric wire 9.
• all contact elements 5 are placed onto the base body 4 which is to be electroplated and make electrical contact with the current source 8 by means of the contact element carriers 7.
• the figure shows three frame-shaped contact element carriers 7 with five contact elements 5 attached to each.
• the contact elements 5 are fixed to each of the contact element carriers in such a manner that they are movable both relative to each other and relative to the contact element carrier 7, so that individual adjustment of the contact elements 5 can be made with reference to the size or geometric shape of the base body 4 which is to be electroplated.
• Fig. 2 shows the second process step as described in the invention.
• the contact elements are removed and an unbroken metal coat is formed.
• the metal coat produced in the first process step is connected to the current source 8 by means of the electric wire 9.
• an also nearly homogeneous electrical field is built up which leads to the still void spots in the metal coat 10 being closed by metal deposition, and an unbroken metal coat is created.
• the base body 4 is again removed from the electrolyte 2.
• Fig. 3 shows an alternative version of a metallic grate 11 which serves as an area contact element and which is provided with insulation except for the contact points.
• the work piece to be electroplated is laid onto the grate 11 with the surface to be electroplated toward the grate and fed through the electrolyte 2 in the horizontal process.
• This is shown schematically in Fig. 4.
• This can be viewed as grate 11 forming an endless band which, at the same time, serves as the conveyor.
• the grate 1 1 is connected to a current source 8 by sliding contacts 15, for example.
• the base bodies 4 are laid on the grate 11 at the loading station 16.
• the loading station 16 is located outside the electrolyte tank 17.
• the base bodies 4 laying on the grate 11 are transported in direction 14 and inserted into electrolyte tank 17 and immersed in the electrolyte 2. Due to the fact that the grate 11 generally runs parallel to the electrolyte surface 3 this process is also referred to as the horizontal process, in contrast to the previously mentioned vertical process.
• the base bodies 4 are removed from the electrolyte tank 17 in the direction 14 and transported to the unloading station 18. There, the base bodies 4 are removed from the grate 1 1. In order to avoid permanent electroplating of the contact points, the metal deposited there can be dissolved by means of the counter anode 19. Subsequent to the completion of the first process step and the build-up of metal coats in accordance with Fig. 4, there follows in a manner similar to the vertical process already described above, the build-up of the unbroken metal covering.
• Fig. 5 and 6 each show two alternatives of a contact element 5 located on a contact element carrier 7.
• the contact elements shown in Fig. 5 and 6 differ due to their relative movability in the lifting direction 20. This is achieved by a suitable spring element.
• the contact elements are designed as follows: The current-carrying contact pin 21 is movable radially relative to the base body 4 (lifting direction 20). The contact pin 21 is surrounded by insulation 22 and attached to the contact element carrier 7 by a threaded connector 23.
• This design has the advantage of fitting the contact element 5 also to a non-level surface of the base body 4. By this method it is ensured that multiple contact elements 5 contact the base body 4, and thus an electrical connection is established between the base body 4 and the current source 6.

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• 2000
  • 2000-02-18 DE DE10007435A patent/DE10007435A1/de not_active Withdrawn
• 2001
  • 2001-02-20 KR KR1020017013256A patent/KR20020021629A/ko not_active Application Discontinuation
  • 2001-02-20 IL IL14589001A patent/IL145890A0/xx unknown
  • 2001-02-20 US US09/959,105 patent/US20020157959A1/en not_active Abandoned
  • 2001-02-20 BR BR0104544-0A patent/BR0104544A/pt not_active Application Discontinuation
  • 2001-02-20 AU AU2001237942A patent/AU2001237942A1/en not_active Abandoned
  • 2001-02-20 CA CA002369687A patent/CA2369687A1/en not_active Abandoned
  • 2001-02-20 CN CN01800987A patent/CN1366563A/zh active Pending
  • 2001-02-20 WO PCT/US2001/001235 patent/WO2001061079A1/en not_active Application Discontinuation
  • 2001-02-20 EP EP01910324A patent/EP1198624A4/de not_active Withdrawn
  • 2001-02-20 MX MXPA01010570A patent/MXPA01010570A/es not_active Application Discontinuation

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Non-Patent Citations (1)

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