Method for depositing a metal on a surface

Claim 1

A method for selectively metallizing a surface of a substrate comprising the steps of: (a) depositing on the surface a layer of a sensitizing composition by treating the surface with a solution comprising at least (a') a reducible salt of a non-noble metal, selected from the group consisting of a reducible salt of copper, a reducible salt of nickel and a reducible salt of cobalt and (b') a light radiation sensitive reducing agent for said salt; (b) exposing said layer-deposited surface to a source of light radiant energy to reduce said metal salt to a reduced metal salt species and wherein at least one of said treating steps is restricted to a selected pattern on the surface to produce a real image of the reduced metal salt species in the selected pattern which is capable of directly catalyzing the deposition thereon of a metal from an electroless metal deposition solution; and (c) treating said real image containing surface, prior to exposure thereof to an electroless metal deposition solution, with a fixing solution comprising a reducing agent selective for the non-noble metal ions of the salt, contained within the real image, selected from the group consisting of formaldehyde and paraformaldehyde when said salt is a reducible salt of copper, and formaldehyde, paraformaldehyde and a hypophosphite species when said salt is a reducible salt of nickel or cobalt, to stabilize the pattern.

Claim 2

A method for selectively metallizing a surface of a substrate comprising the steps of: (a) depositing on the surface a layer of a sensitizing composition by treating the surface with a solution comprising at least (a') a reducible salt of a non-noble metal, selected from the group consisting of a reducible salt of copper, a reducible salt of nickel and a reducible salt of cobalt and (b') a light radiation sensitive reducing agent for said salt; (b) exposing said layer-deposited surface to a source of light radiant energy to reduce said metal salt to a reduced metal salt species and wherein at least one of said treating steps is restricted to a selected pattern on the surface to produce a real image of the reduced metal salt species in the selected pattern which is capable of directly catalyzing the deposition thereon of a metal from an electroless metal deposition solution; and (c) treating said real image containing surface, prior to exposure thereof to an electroless metal deposition solution, with a fixing solution comprising a reducing agent selective for the non-noble metal ions of the salt, contained within the real image, selected from the group consisting of formaldehyde and paraformaldehyde when said salt is a reducible salt of copper, and formaldehyde, paraformaldehyde and a hypophosphite species when said salt is a reducible salt of nickel or cobalt, to stabilize the pattern.

Claim 13

A method for depositing a metal pattern on a dielectric surface which comprises: (a) treating the surface with a sensitizing solution comprising at least (1) a reducible salt of a non-noble metal, selected from the group consisting of a reducible salt of copper, a reducible salt of nickel and a reducible salt of cobalt, and (2) a light radiation sensitive reducing agent for said salt, to form a sensitized surface; (b) selectively exposing said sensitized surface to a source of light radiant energy to reduce said metal salt to produce a reduced metal salt species in the form of a real image corresponding to the desired metal pattern; and (c) treating said real image containing surface, prior to removing unexposed portions of said metal salt thereform, with a fixing solution comprising a selective reducing agent for said non-noble metal ions of said salt contained within the real image, selected from the group consisting of formaldehyde and paraformaldehyde when said salt is a reducible salt of copper, and formaldehyde, paraformaldehyde and a hypophosphite species when said salt is a reducible salt of nickel or of cobalt, to stabilize said real image.

Claim 14

A method for depositing a metal pattern on a dielectric surface which comprises: (a) treating the surface with a sensitizing solution comprising at least (1) a reducible salt of a non-noble metal, selected from the group consisting of a reducible salt of copper, a reducible salt of nickel and a reducible salt of cobalt, and (2) a light radiation sensitive reducing agent for said salt, to form a sensitized surface; (b) selectively exposing said sensitized surface to a source of light radiant energy to reduce said metal salt to produce a reduced metal salt species in the form of a real image corresponding to the desired metal pattern; and (c) treating said real image containing surface, prior to removing unexposed portions of said metal salt thereform, with a fixing solution comprising a selective reducing agent for said non-noble metal ions of said salt contained within the real image, selected from the group consisting of formaldehyde and paraformaldehyde when said salt is a reducible salt of copper, and formaldehyde, paraformaldehyde and a hypophosphite species when said salt is a reducible salt of nickel or of cobalt, to stabilize said real image.