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Laser-Enhanced Plating on Certain Aluminum Alloys using Copper Exchange Plating

IP.com Disclosure Number: IPCOM000104343D
Original Publication Date: 1993-Apr-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

von Gutfeld, RJ: AUTHOR [+4]

Abstract

In general, it is difficult, if not impossible, to plate directly onto aluminum without extensive pre-processing of the surface. However, with the small addition of copper to the aluminum (for example, by way of simultaneous sputtering or beam evaporation of the two constituents), it becomes possible to plate copper patterns using laser enhanced thermal exchange plating. The general mechanism for this type of plating relies on a small shift in local rest potential caused by a local temperature variation at the solution/substrate interface. Charge conservation is maintained through simultaneous etching that takes place from the surrounding unheated region. No external potential (or electrodes) is (are) applied.

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Laser-Enhanced Plating on Certain Aluminum Alloys using Copper Exchange Plating

      In general, it is difficult, if not impossible, to plate
directly onto aluminum without extensive pre-processing of the
surface.  However, with the small addition of copper to the aluminum
(for example, by way of simultaneous sputtering or beam evaporation
of the two constituents), it becomes possible to plate copper
patterns using laser enhanced thermal exchange plating.  The general
mechanism for this type of plating relies on a small shift in local
rest potential caused by a local temperature variation at the
solution/substrate interface.  Charge conservation is maintained
through simultaneous etching that takes place from the surrounding
unheated region.  No external potential (or electrodes) is (are)
applied.  To obtain the required temperature change, a focused laser
is directed onto the sample while the sample is submerged in an
electrolytic plating solution, in this case copper sulfate.  Under
appropriate conditions, selective copper deposition will occur in the
laser heated region [*].  Although aluminum is considerably less
noble than copper, a situation generally ideal for exchange plating,
it has been essentially impossible to plate copper from a copper
sulfate solution onto pure aluminum by this laser process.  However,
when aluminum is doped with &tilde.3% (or more) copper, the laser
thermal exchange process becomes effective.  This has been shown in a
number of...