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AssigneeRichardson Chemical Company
InventorGlenn O. Mallory, Jr.
Estimating the term…
Polyalloy catalytic coating formulations are used for preparing a metallic substrate surface to enhance subsequent plating thereover of nickel, cobalt or polyalloys including nickel or cobalt. At the same time, these catalytic formulations can be rinsed subsequent to their application onto the substrate and prior to the electroless deposition thereover. Improved products such as printed wiring boards may be made with these catalytic formulations. Such boards are prepared by depositing metal and forming circuitry patterns by using resists, etching techniques and the like which typically leave copper specks on the non-conductive board. The invention discourages electroless deposition by a nickel-containing plating bath over embedded copper specks, thereby reducing the possibility of developing bridging within the circuitry and in general undesirably increasing the conductivity of the board at locations other than on the circuitry pattern to produce printed wiring boards that are extremely resistant to developing short circuiting problems.
A method for preparing a printed wiring board which comprises treating a wiring board having a circuitry pattern thereon with a polymetallic catalyzing agent bath including a deposition-enhancing metal selected from the group consisting of nickel, cobalt, and combinations thereof, and a secondary metal selected from the group consisting of tin, molybdenum, copper, tungsten, and combinations thereof, said catalyzing agent bath including copper only when it also includes one or more of tin, molybdenum or tungsten as said secondary metal, said bath including an ester complex of a polyhydric compound, said catalyzing agent bath enhancing subsequent overplating onto said circuitry pattern, said treating step lasting for a time period sufficient to nucleate the surface of the circuitry pattern and insufficient to deposit a generally continuous plating film thereon, said treating step being followed by rinsing said catalyzing agent bath treated circuit board with an aqueous rinsing agent, said treating step and said rinsing step cooperating to enhance catalyzing agent film formation onto said circuitry pattern in preference to portions of the wiring board that are not within the circuitry pattern to provide a preferentially catalyzed wiring board;
A method for catalyzing a non-catalytic metal surface comprising treating the non-catalytic metal surface with a polymetallic catalyzing agent bath including a deposition-enhancing metal selected from the group consisting of nickel, cobalt and combinations thereof, and a secondary metal selected from the group consisting of tin, molybdenum, copper, tungsten and combinations thereof, said catalyzing agent bath including copper only when it also includes one or more of tin, molybdenum or tungsten as said secondary metal, said bath including an ester complex of a polyhydric compound, said treating being under slightly acidic to generally alkaline conditions and being for a period of time sufficient to nucleate said non-catalytic metal surface and insufficient to deposit a generally continuous plating film thereonto, said treating step being followed by rinsing said nucleated metal surface with an aqueous rinsing agent for enhancing preferential catalyzing agent film formation onto said nucleated metal surface.
Dependencies are inferred from the claim text.