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Plating Solutions With Metal Suspensions for Thermal Exchange Plating

IP.com Disclosure Number: IPCOM000101701D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 79K

Publishing Venue

IBM

Related People

Vigliotti, DR: AUTHOR [+2]

Abstract

One of the requirements in the repair or plating of circuits using thermally driven exchange plating - the "thermobattery effect" - is that charge neutrality must be maintained in the solution. Consequently, for every ion in solution that becomes reduced and is plated out, another metallic atom must be ionized, i.e., give up an electron, and go into solution. Thus, when thermally driven exchange plating is carried out on copper lines that are part of a composite metallurgical structure or on metals which do not readily dissolve due to their position in the electronegativity table, it may become necessary to provide an additional donor source of ions to achieve the desired exchange plating.

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Plating Solutions With Metal Suspensions for Thermal Exchange Plating

       One of the requirements in the repair or plating of
circuits using thermally driven exchange plating  - the
"thermobattery effect" - is that charge neutrality must be maintained
in the solution.  Consequently, for every ion in solution that
becomes reduced and is plated out, another metallic atom must be
ionized, i.e., give up an electron, and go into solution.  Thus, when
thermally driven exchange plating is carried out on copper lines that
are part of a composite metallurgical structure or on metals which do
not readily dissolve due to their position in the electronegativity
table, it may become necessary to provide an additional donor source
of ions to achieve the desired exchange plating.

      Provision of such a donor source of metal ions for thermally
driven exchange plating has given rise to difficulties in the past.
For example, it has previously been suggested for thermally driven
exchange plating of copper that bulk copper be placed near the region
to be copper plated to act as a donor of metal ions for the exchange
plating.  However, for very small circuits, it is frequently
impractical to position bulk copper suitably for effective thermally
driven exchange plating.  The difficulties involved in positioning
bulk copper become compounded when there are several separated sites
in the circuit on which it is desired to plate copper.

      In this article an alternative method is disclosed for
achieving effective thermally driven exchange plating.  A fine
metallic powder is added to the plating solution to contribute the
requisite donor atoms for the exchange plating.  For example, copper
powder may be added to an acid copper solution to achieve thermally
driven exchange plating of copper.  In general, it should be possible
to use particles of any metal less noble tha...