In situ plating and etching of materials covered with a surface film

• US 20080142367A1
• Filed: 06/22/2007
• Published: 06/19/2008
• Est. Priority Date: 02/08/2005
• Status: Active Grant

• Current Assignee: Alan C. West, Robert J Von Gutfeld
• Original Assignee: Alan C. West, Robert J Von Gutfeld
• Inventors: West, Alan C., Von Gutfeld, Robert J.
• Granted Patent: US 8,529,738 B2
• Time in Patent Office: Days
• US Class Current: 205/92
• CPC Class Codes: C25D 17/00 Constructional parts, or assemblies thereof, of cells for electrolytic coating
• CPC Class Codes: C25D 17/02 Tanks; Installations therefor
• CPC Class Codes: C25D 5/022 using masking means
• CPC Class Codes: C25D 5/08 Electroplating with moving electrolyte e.g. jet electroplating using locally applied jets of electrolyte C25D5/026
• CPC Class Codes: C25D 5/18 Electroplating using modulated, pulsed or reversing current
• CPC Class Codes: C25D 5/22 Electroplating combined with mechanical treatment during the deposition

Abstract

Systems and methods for plating and/or etching of hard-to-plate metals are provided. The systems and methods are designed to overcome the deleterious effect of superficial coating or oxide layers that interfere with the plating or etching of certain metal substrates. The systems and methods involve in situ removal of coating materials from the surfaces of the metal substrates while the substrates are either submerged in plating or etching solutions, or are positioned in a proximate enclosure just prior to submersion in the plating or etching solutions. Further, the substrates can be in contact with a suitable patterning mask to obtain patterned oxide-free regions for plating or etching. This in situ removal of coating layers may be achieved by pulse heating or photoablation of the substrate and the inhibiting coating layers. Electrical energy or laser light energy may be used for this purpose. Additionally or alternatively, the coating materials may be removed by mechanical means.

Claims

1. A system for metal-plating and etching a substrate by action of a chemical solution in a tank containing the chemical solution, the substrate covered by an interfering surface coating, the system comprising:

a substrate-holding fixture disposed relative to the tank so that the portions of the substrate are submerged in the contained chemical solution;

a surface-coating removal mechanism that is operable “

in situ”

on the submerged substrate portions to remove the interfering surface coating and expose uncoated substrate surfaces to the action of the contained chemical solution,

whereby metal-plating and etching can occur directly on the substrate without interference by the surface coating.

2. The system of claim 1, wherein the surface-coating removal mechanism comprises a device configured for directing an energy beam onto submerged substrate surfaces to generate heat, whereby the interfering surface coating is removed.

3. The system of claim 1, wherein the substrate comprises electrically conductive material, and wherein the surface-coating removal mechanism comprises an arrangement for passing electrical current through the submerged substrate to generate heat, whereby the interfering surface coating is removed.

4. The system of claim 1, wherein the substrate-holding fixture is further configured as an electrode and a counter-electrode is disposed in the tank forming an electrolytic cell, whereby the chemical solution contained in the tank can act to electroplate or electroetch exposed clean substrate surfaces.

5. The system of claim 4 wherein the electrolytic cell and the surface-coating removal mechanism are configured for one of sequential operation and concurrent operation.

6. The system of claim 1 comprising an arrangement for circulating the chemical solution in the tank, whereby formation of bubbles on surfaces of the submerged substrate is avoided.

7. The system of claim 1 wherein the surface-coating removal mechanism is operable “

in situ”

on the submerged substrate portions to mechanically remove the interfering surface coating and expose clean substrate surfaces to the action of the chemical solution.

8. The system of claim 7 wherein the surface-coating removal mechanism comprises:

a movable arm; and

a scribe with a sharpened end mounted on the moveable arm, wherein the sharpened end is disposed against a surface of the substrate and wherein the movable arm is operable to scan the sharpened end along the surface of the substrate to mechanically remove the interfering surface coating.

9. The system of claim 7 further configured for processing wire or flat stock substrates, wherein the surface-coating removal mechanism comprises a die having a sharp edge, and wherein the system further comprises a material handling arrangement which operates to draw the wire or flat stock substrates through the die so that the sharp edge mechanically removes the interfering surface coating.

10. The system of claim 9 wherein the material handling arrangement comprises a reel-to-reel material handling arrangement.

11. The system of claim 1 wherein the surface-coating removal mechanism is disposed proximate to the tank so that the substrate can be immersed in the chemical solution while its surfaces are uncoated, whereby metal-plating and etching can occur directly on the substrate by action of the chemical solution without interference by the surface coating.

12. The system of claim 11 wherein the surface-coating removal mechanism comprises at least one of a mechanical abrasion device, a laser, a stamping tool, an induction heating coil, a magnetron, and an ion gun.

13. The system of claim 1 further comprising:

a second tank containing the chemical solution;

a substrate transferor configured to move the substrate from the first fluid holding tank to the second fluid holding tank, the transferor disposed relative to the tanks so that the uncoated substrate surfaces are exposed to the action of the contained chemical solution in the second fluid holding tank,

whereby metal-plating and etching can occur directly on the substrate without interference by the surface coating.

14. A method for metal-plating or etching a substrate by action of a chemical solution, the substrate covered by an interfering surface coating, the method comprising:

submerging portions of the substrate in the chemical solution; and

removing the interfering surface coating “

in situ”

while portions of the substrate are submerged in the chemical solution to expose uncoated substrate material to the action of the chemical solution,

whereby metal-plating or etching can occur directly on the substrate without interference by the surface coating.

15. The method of claim 14 wherein removing the interfering surface coating comprises generating heat by one of passing electrical current through the submerged substrate, directing laser light onto surfaces of the submerged substrate, and directing an energy beam onto surfaces of the submerged substrate, whereby the interfering surface coating is removed.

16. The method of claim 14 wherein removing the interfering surface coating comprises drawing the submerged substrates through a die with a sharp edge disposed against the surfaces of the substrate, whereby the interfering surface coating is mechanically removed.

17. The method of claim 14 adapted for processing wire or flat stock substrates, further comprising the step of:

operating a material handling arrangement to draw the wire or flat stock substrates through a die having a sharp edge,

wherein the surface-coating removal step comprises drawing the wire or flat stock substrates through the die so that the sharp edge contacts surfaces of the drawn substrates to mechanically remove the interfering surface coating.

18. A method of claim 14 further comprising:

disposing the substrate in proximity of a tank holding the chemical solution;

removing the interfering surface coating on the substrate and exposing uncoated substrate surfaces, while the substrate is proximate to the tank holding the chemical solution; and

immersing the substrate in the chemical solution while its surfaces are uncoated, whereby metal-plating and etching can occur directly on the substrate by action of the chemical solution without interference by the surface coating.

19. A method of claim 14 wherein removing the interfering surface coating on the substrate in a first tank and exposing uncoated substrate surfaces comprises immersing the substrate in a second tank containing a fluid that is free of plating metal ions and moving the substrate to the tank containing the chemical solution so that uncoated substrate surfaces are exposed to the action of the chemical solution,

whereby metal plating or etching can occur directly on the substrate without interference by the surface coating.

20. A metal-plated article fabricated by the method of claim 14, wherein the metal-plated article comprises one of a refractory metal substrate, an aluminum substrate and wherein the metal plating comprises one of cadmium, zinc, silver, gold, tin, copper, nickel and chromium.

21. The method of claim 14, wherein the substrate has disposed thereon a contact patterning mask defining masked and mask opening regions, wherein removing the interfering surface coating “

in situ”

comprises removing interfering surface coatings in the mask opening regions, whereby metal-plating or etching can occur directly on the substrate in pattern.

22. A system for plating and etching of a substrate covered with an inhibiting coating, the system comprising:

a cell for holding an electrolyte solution in which the substrate is immersed, the substrate acting as an electrode;

a counter electrode disposed in the cell; and

a voltage source connected across the electrode and counter electrode, wherein the voltage source is configured to apply a first voltage pulse having a pulse width less than about 1 second and a voltage amplitude greater than about 20V across the electrode and counter electrode, and further configured to apply a lower voltage cw signal across the electrode and counter electrode.

23. The system of claim 22, wherein the voltage source is configured to apply a first voltage pulse having a voltage amplitude in the range of about 20V to 1000V across the electrode and counter electrode.

24. The system of claim 22, wherein the voltage source is configured to apply a first voltage pulse having a pulse width in the range of about 10 ns to 100 ms across the electrode and counter electrode.

25. The system of claim 22, wherein the voltage source is configured to apply a lower voltage modulated cw signal across the electrode and counter electrode.

26. The system of claim 22, wherein the voltage source is configured to apply a lower voltage cw signal which in the range of about +0.05 to 5 volts.

27. The system of claim 22, wherein the voltage source is a programmable voltage source.

28. A reel-to-reel system for plating and etching substrates covered with an inhibiting coating, the system comprising:

a cell holding an electrolyte;

a supply reel for continuously feeding a substrate into the electrolyte for processing, wherein the substrate acts as a working electrode in the electrolyte;

a split set of a first and second counter electrodes mounted opposite the working electrode in the electrolyte;

a take-up reel for continuously taking up the processed substrate from the electrolyte;

a programmable voltage source connected across the working electrode and the split set of counter electrodes, wherein the voltage source is configured to apply a first voltage pulse having a pulse width less than 1 second and a voltage greater than about 20V across the working electrode and the first counter electrode, and further configured to apply a lower voltage cw signal across the working electrode and the second counter electrode.

29. The system of claim 28, wherein the programmable voltage source is configured to apply a first voltage pulse having a pulse width on the order of 10 ns-100 ms and an amplitude in the range of about 20-100V.

30. The system of claim 28, wherein the programmable voltage source is configured to apply a lower voltage cw signal having voltage amplitude in the range of about 0.01 to 10 volts between the working electrode and the second counter electrode.

31. A method for plating and etching a substrate with an inhibiting coating, the method comprising:

immersing the substrate in an electrolyte, the substrate acting as a working electrode;

disposing a counter electrode opposite the working electrode in the electrolyte;

applying a high voltage pulse between the working and counter electrodes; and

applying a low voltage pulse of the same polarity as the high voltage pulse between said working and counter electrodes following the application of said high voltage pulse.

33. The system of claim 31 further comprising a voltage supply connected to said substrate and counter electrode.

34. The system of claim 31 further comprising a substrate holder which is movable to orient the held substrate relative to the incident electrolyte jet.

35. The system of claim 31 wherein the pulsed laser is configured to generate pulse widths in the range of about 10 ps to 10 ms and fluence in the range of about 1-5,000 mJ/pulse.

32. A system that affords plating and etching of a substrate covered with an inhibiting coating, the system comprising:

a chamber holding an electrolyte, wherein the chamber has an optical entrance window across from and aligned with an electrolyte exit nozzle, and wherein the chamber can be pressurized to form an electrolyte jet which is incident on the substrate through the nozzle, the substrate acting as an electrode;

a counter electrode disposed in the chamber holding the electrolyte; and

a pulsed laser configured to generate a laser beam which passes through the optical window and the nozzle, and along the interior of the electrolyte jet, so that the electrolyte jet and the laser beam are both incident on to the substrate.

36. A system that affords plating and etching of a substrate covered with an inhibiting coating, the system comprising:

an electrically insulating curtain which defines a volume of electrolyte in contact with a surface portion of the substrate, the substrate acting as an working electrode; and

a counter electrode disposed in the defined volume of electrolyte;

a pulsed laser configured to generate a laser beam which passes through the defined volume of electrolyte on to the surface portion of the substrate.

37. The system of claim 36 further comprising a voltage supply connected to said substrate and counter electrode.

38. The system of claim 36 further comprising a substrate holder which is movable to orient the held substrate relative to the defined volume of the electrolyte.

39. The system of claim 38 wherein the pulsed laser is configured to generate pulse widths in the range of about 10 ps-10 ms and fluence in the range of about 1-5,000 mJ/pulse.

40. A method for plating and/or etching a substrate with an inhibiting coating, the method comprising:

immersing the substrate in a chamber holding an electrolyte, wherein the chamber has an optical entrance window across from and aligned with an electrolyte exit nozzle, and wherein the chamber can be pressurized to form an electrolyte jet which is incident on the substrate through the nozzle, the substrate acting as an electrode;

disposing a counter electrode in the chamber holding the electrolyte; and

pulsing a laser beam through the optical window and the nozzle and along the interior of an electrolyte jet so that the electrolyte jet and the laser beam are both incident on to a surface portion the substrate, and so that the laser beam acts on the inhibiting coating to prepare the surface portion the substrate for electrolytic plating and/or etching action by the electrolyte jet.

41. A method for plating and etching a substrate with an inhibiting coating, the method of comprising:

using an electrically insulating curtain to define a volume of electrolyte in contact with a surface portion of the substrate, the substrate acting as a working electrode;

disposing a counter electrode in the defined volume of electrolyte; and

directing a pulsed laser beam through the defined volume of electrolyte on to the surface portion of the substrate, so that the pulsed laser beam acts on the inhibiting coating to prepare the surface portion of the substrate for electrolytic plating and/or etching action by the defined volume of electrolyte in contact with the surface portion of the substrate.