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Process for Photochemical Catalysis of Electroless Copper Plating Onto Polymeric Substrates

IP.com Disclosure Number: IPCOM000102477D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Baum, TH: AUTHOR [+4]

Abstract

The selective fabrication of metallic films from electroless plating baths has been achieved via an iron/palladium catalytic mixture which is then photochemically activated. The use of potassium or ammonium iron (III) oxalate trihydrate in the presence of palladium (II) salts can be effectively used as a photoactive catalyst. Ultraviolet irradiation results in the formation of palladium metal in the exposed regions; the palladium then acts as a catalyst for the initiation of electroless plating of metals.

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Process for Photochemical Catalysis of Electroless Copper Plating Onto Polymeric Substrates

       The selective fabrication of metallic films from
electroless plating baths has been achieved via an iron/palladium
catalytic mixture which is then photochemically activated. The use of
potassium or ammonium iron (III) oxalate trihydrate in the presence
of palladium (II) salts can be effectively used as a photoactive
catalyst.  Ultraviolet irradiation results in the formation of
palladium metal in the exposed regions; the palladium then acts as a
catalyst for the initiation of electroless plating of metals.

      In the process described here, several sources of radiation may
be utilized with wavelengths in the ultraviolet (UV), ranging from
185 to 400 nms. The source of light may be a lamp or an excimer
laser. Other forms of energy may also be used such as X-ray, ion and
electron beams.  The primary requirement of the energetic source is
that the iron (III) oxalate is reduced to an iron (II) species which
in turn reduces the palladium (II) to palladium metal. The energetic
source could be imaged or focussed to produce selective regions of
exposure.

      This process has been achieved on a variety of substrates, such
as metals, semiconductors, ceramic and polymer or polymer composites.
The photoactive iron/palladium mixture can be sprayed, dipped or
spin- coated on to the desired substrate to be metallized. The UV
exposure dose will be determined by the surface concentration of the
photoactive mixture, the resolution of surface features or by the
desired plating activity of the latent photoimage.

      For metallization of polymer substrates, a thin adhesion layer
may be required to provide good metal-to-polymer adhesion of the
final metal...