Method for depositing a metal on a surface

Claim 1

A method of depositing a metal on a surface of a substrate including the walls of at least one aperture contained in the substrate, which comprises: (a) coating the surface with a sensitizing solution comprising at least a reducible salt of a non-noble metal dissolved in a binary solvent, for providing a continuous metal deposit on the walls, consisting essentially of water and an alcohol having a structural formula of ##STR3## where R 1 , R 2 , and R 3 are members selected from the group consisting of an alkyl group having 1 to 7 carbon atoms and the hydrogen atom, where said alcohol has a total of 2 to 8 carbon atoms and where said alcohol is present in an amount of at least 5 weight percent when said alcohol has two carbon atoms and in an amount of at least 0.1 weight percent when said alcohol has more than two carbon atoms; and

Claim 2

A method of depositing a metal on a surface of a substrate including the walls of at least one aperture contained in the substrate, which comprises: (a) coating the surface with a sensitizing solution comprising at least a reducible salt of a non-noble metal dissolved in a binary solvent, for providing a continuous metal deposit on the walls, consisting essentially of water and an alcohol having a structural formula of ##STR3## where R 1 , R 2 , and R 3 are members selected from the group consisting of an alkyl group having 1 to 7 carbon atoms and the hydrogen atom, where said alcohol has a total of 2 to 8 carbon atoms and where said alcohol is present in an amount of at least 5 weight percent when said alcohol has two carbon atoms and in an amount of at least 0.1 weight percent when said alcohol has more than two carbon atoms; and

Claim 27

A method for selectively metallizing a dielectric surface of a substrate having at least one aperture therein 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 reducible salt of a non-noble metal dissolved in a binary solvent, for providing an essentially void-free metallization on the walls of the aperture, consisting essentially of water and an alcohol having a structural formula of ##STR4## where R 1 , R 2 , and R 3 are members selected from the group consisting of an alkyl group having 1 to 7 carbon atoms and the hydrogen atom, where said alcohol has a total of 2 to 8 carbon atoms and where said alcohol is present in an amount of at least 5 weight percent when said alcohol has two carbon atoms and in an amount of at least 0.1 weight percent when said alcohol has more than two carbon atoms; and (b) treating said layer by (1) drying it and exposing it to a source of light radiant energy or (2) exposing it to a chemical reducing agent or (3) heating it to reduce said metal salt to metallic nuclei thereof, and wherein at least one of said treating steps (a) or (b) above, is restricted to a selected pattern on the surface to produce a real image of the metallic nuclei in the selected pattern which is capable of directly catalyzing the deposition thereon of a metal from an electroless metal deposition solution.

Claim 28

A method for selectively metallizing a dielectric surface of a substrate having at least one aperture therein 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 reducible salt of a non-noble metal dissolved in a binary solvent, for providing an essentially void-free metallization on the walls of the aperture, consisting essentially of water and an alcohol having a structural formula of ##STR4## where R 1 , R 2 , and R 3 are members selected from the group consisting of an alkyl group having 1 to 7 carbon atoms and the hydrogen atom, where said alcohol has a total of 2 to 8 carbon atoms and where said alcohol is present in an amount of at least 5 weight percent when said alcohol has two carbon atoms and in an amount of at least 0.1 weight percent when said alcohol has more than two carbon atoms; and (b) treating said layer by (1) drying it and exposing it to a source of light radiant energy or (2) exposing it to a chemical reducing agent or (3) heating it to reduce said metal salt to metallic nuclei thereof, and wherein at least one of said treating steps (a) or (b) above, is restricted to a selected pattern on the surface to produce a real image of the metallic nuclei in the selected pattern which is capable of directly catalyzing the deposition thereon of a metal from an electroless metal deposition solution.

Claim 48

A method for making printed circuit boards having at least one through hole therein, which comprises: (a) treating an electrically non-conductive base with a solution comprising a reducible salt of a non-noble metal, selected from the group consisting of reducible salts of copper, nickel, cobalt and iron, a light radiation-sensitive reducing compound and a secondary reducer, dissolved in a binary solvent, for providing an essentially void-free metallization on the walls of the aperture, consisting essentially of water and an alcohol having a structural formula of ##STR5## where R 1 , R 2 , and R 3 are members selected from the group consisting of an alkyl group having 1 to 7 carbon atoms and the hydrogen atom, where said alcohol has a total of 2 to 8 carbon atoms and where said alcohol is present in an amount of at least 5 weight percent when said alcohol has two carbon atoms and in an amount of at least 0.1 weight percent when said alcohol has more than two carbon atoms; and (b) drying said treated base; (c) exposing said dried base to light radiant energy in selected areas including the walls of the through hole to produce metallic nuclei in the form of a real image corresponding to the desired circuit pattern; (d) rinsing said exposed base to remove unexposed metal salts; and (e) exposing said real image to an electroless metal deposition solution to deposit an electroless metal thereon.

Claim 49

A method for making printed circuit boards having at least one through hole therein, which comprises: (a) treating an electrically non-conductive base with a solution comprising a reducible salt of a non-noble metal, selected from the group consisting of reducible salts of copper, nickel, cobalt and iron, a light radiation-sensitive reducing compound and a secondary reducer, dissolved in a binary solvent, for providing an essentially void-free metallization on the walls of the aperture, consisting essentially of water and an alcohol having a structural formula of ##STR5## where R 1 , R 2 , and R 3 are members selected from the group consisting of an alkyl group having 1 to 7 carbon atoms and the hydrogen atom, where said alcohol has a total of 2 to 8 carbon atoms and where said alcohol is present in an amount of at least 5 weight percent when said alcohol has two carbon atoms and in an amount of at least 0.1 weight percent when said alcohol has more than two carbon atoms; and (b) drying said treated base; (c) exposing said dried base to light radiant energy in selected areas including the walls of the through hole to produce metallic nuclei in the form of a real image corresponding to the desired circuit pattern; (d) rinsing said exposed base to remove unexposed metal salts; and (e) exposing said real image to an electroless metal deposition solution to deposit an electroless metal thereon.

Claim 57

A method of depositing a metal on a surface of a substrate comprising the steps of: (a) treating the surface with a light radiation-sensitive solution comprising a reducible salt of a non-noble metal, selected from the group consisting of copper, nickel, cobalt and iron, a radiation-sensitive reducing agent for said salt and a secondary reducer consisting essentially of lactose, dissolved in a binary solvent, consisting essentially of water and an alcohol having a structural formula of ##STR6## where R 1 , R 2 , and R 3 are members selected from the group consisting of an alkyl group having 1 to 7 carbon atoms and the hydrogen atom, where said alcohol has a total of 2 to 8 carbon atoms and where said alcohol is present in an amount of at least 5 weight percent when said alcohol has two carbon atoms and in an amount of at least 0.1 weight percent when said alcohol has more than two carbon atoms; and (b) exposing at least a portion of said solution treated surface, prior to drying thereof, to a source of light radiant energy for a period of time sufficient to reduce the metal salt to metallic nuclei thereof which are capable of directly catalyzing the deposition thereon of a metal from an electroless metal deposition solution.

Claim 58

A method of depositing a metal on a surface of a substrate comprising the steps of: (a) treating the surface with a light radiation-sensitive solution comprising a reducible salt of a non-noble metal, selected from the group consisting of copper, nickel, cobalt and iron, a radiation-sensitive reducing agent for said salt and a secondary reducer consisting essentially of lactose, dissolved in a binary solvent, consisting essentially of water and an alcohol having a structural formula of ##STR6## where R 1 , R 2 , and R 3 are members selected from the group consisting of an alkyl group having 1 to 7 carbon atoms and the hydrogen atom, where said alcohol has a total of 2 to 8 carbon atoms and where said alcohol is present in an amount of at least 5 weight percent when said alcohol has two carbon atoms and in an amount of at least 0.1 weight percent when said alcohol has more than two carbon atoms; and (b) exposing at least a portion of said solution treated surface, prior to drying thereof, to a source of light radiant energy for a period of time sufficient to reduce the metal salt to metallic nuclei thereof which are capable of directly catalyzing the deposition thereon of a metal from an electroless metal deposition solution.

Claim 59

A method of depositing a metal pattern on a surface of a substrate which comprises: (a) treating the surface with a solution comprising a reducible salt of a non-noble metal selected from the group consisting of reducible salts of copper, nickel, cobalt and iron, a radiation-sensitive reducing compound, and a suitable secondary reducer combined with a real image stabilizer comprising lactose; (b) drying said treated surface; and (c) selectively exposing said dried surface to a source of light radiant energy, wherein the improvement comprises: in step (a) the solution additionally comprises a real image former and stabilizer comprising lactose which permits the formation of metallic nuclei to form a stable real image.

Claim 60

A method of depositing a metal pattern on a surface of a substrate which comprises: (a) treating the surface with a solution comprising a reducible salt of a non-noble metal selected from the group consisting of reducible salts of copper, nickel, cobalt and iron, a radiation-sensitive reducing compound, and a suitable secondary reducer combined with a real image stabilizer comprising lactose; (b) drying said treated surface; and (c) selectively exposing said dried surface to a source of light radiant energy, wherein the improvement comprises: in step (a) the solution additionally comprises a real image former and stabilizer comprising lactose which permits the formation of metallic nuclei to form a stable real image.