Electroless copper plating bath

Claim 2

The plating solution of claim 1 further characterized by containing an alkaline compound in amount sufficient to provide the solution with a pH in the range of 10 to 14.

Claim 3

The plating solution of claim 3 wherein the iodide ion is present in amount equivalent to about 0.0001-0.01 g./l. of sodium iodide or potassium iodide and the o-phenanthroline in amount of about 0.0001-0.01 g./l.

Claim 4

The plating solution of claim 3 wherein the alkaline compound is an alkali metal hydroxide.

Claim 5

The plating solution of claim 5 further characterized by containing an alkali metal carbonate in addition to the alkali metal hydroxide, and wherein the reducing agent is formaldehyde.

Claim 6

The plating solution of claim 5 wherein the alkali metal hydroxide is sodium hydroxide and the alkali metal carbonate is sodium carbonate.

Claim 7

The plating solution of claim 7 wherein the cupric ion complexing agent is Rochelle salt.

Claim 8

A composition for use in electroless copper plating baths comprising a mixture of o-phenanthroline and a source of iodide ions.

Claim 9

A liquid additive composition for electroless copper plating baths comprising a mixture of o-phenanthroline, iodide ions and an aqueous liquid solvent.

Claim 10

A concentrate composition especially well adapted for use in forming high stability electroless copper plating solutions comprising a mixture of a water-soluble copper salt, a reducing agent for ionic copper, o-phenanthroline, and a source of iodide ions, the amount of o-phenanthroline and of the iodide ion source being a small amount of each sufficient to stabilize the ultimate electroless copper plating solution against spontaneous decomposition but insufficient to prevent copper from depositing from said plating solution.

Claim 11

An aqueous acid concentrate solution especially well adapted for use in forming high stability electroless copper plating solutions comprising an aqueous acid solution of a water-soluble copper salt, a reducing agent for ionic copper, o-phenanthroline, and a water-soluble source of iodide ions, the pH of said concentrate solution being sufficiently below pH 7 to prevent any substantial precipitation of copper therefrom as a cupric hydroxide-containing precipitate and as metallic copper by a redox reaction, the amount of o-phenanthroline and of the iodide ion source being a small amount of each sufficient to stabilize the ultimate electroless copper plating solution against spontaneous decomposition but insufficient to prevent copper from depositing from said plating solution.

Claim 12

The concentrate of claim 12 wherein the source of iodide ions is a material selected from the group consisting of sodium iodide and potassium iodide.

Claim 13

The concentrate solution of claim 12 wherein the reducing agent for ionic copper is formaldehyde, and also conTaining an acid material in amount sufficient to maintain the pH of the concentrate solution sufficiently below pH7 to prevent any substantial precipitation of copper therefrom as a cupric hydroxide-containing precipitate and as metallic copper by a redox reaction.

Claim 14

An aqueous acid concentrate solution especially well adapted for use in forming high stability electroless copper plating solutions containing the following constituents in proportions within the percentage range specified: % by Weight H2SO4(Analytic reagent grade from about 0.02-0.04 CuSO4.5H2O from about 5-9 HCHO (37% concentration) from about 35-45o-Phenanthroline from about 3 X 10 5-3 X 10 3NaI or KI from about 3 X 10 5-3 X 10 3H2O balance, the pH of said concentrate solution being sufficiently below pH 7 to prevent any substantial precipitation of copper therefrom as a cupric hydroxide-containing precipitate and as metallic copper by a redox reaction.

Claim 15

An electroless copper aqueous alkaline plating solution containing the following constituents in amounts within the proportion ranges specified: Soluble Copper salt 20-26 g./l. Rochelle salt 40-55 g./l. Alkali metal hydroxide 10-18 g./l. Formaldehyde (37% concentra-tion 100-150 ml./l. o-Phenanthroline 1 X 10 4-1 X 10 2 g./l. Sodium iodide 1 X 10 4-1 X 10 2 g./l. Alkali metal carbonate 2-10 g./l. the solution having a pH in the range of 10 to 14.

Claim 16

The plating solution of claim 16 wherein the copper salt is copper sulfate.

Claim 17

An electroless copper aqueous alkaline plating solution containing the following constituents in amounts within the proportion ranges specified: Soluble Copper Salt 20-26 g./l. Rochelle salt 40-55 g./l. Alkali metal hydroxide 10-18 g./l. Formaldehyde (37% concentra-tion) 100-150 ml./l. o-Phenanthroline 1 X 10 4-1 X 10 2 g./l. Potassium iodide 1 X 10 4-1 X 10 2 g./l. Alkali metal carbonate 2-10 g./l. the solution having a pH in the range of 10 to 14.

Claim 18

An additive composition for electroless copper plating baths comprising a mixture of o-phenanthroline, a source of iodide ions, and an inert diluent.

Claim 19

The composition of claim 19 wherein the diluent is at least one material selected from the group consisting of an alkali metal hydroxide and an alkali metal carbonate.

Claim 20

The composition of claim 19 wherein the iodide ion source is an alkali metal iodide.

Claim 21

The composition of claim 21 wherein the alkali metal iodide is sodium iodide.

Claim 22

The composition of claim 21 wherein the alkali metal iodide is potassium iodide.