Electroless palladium plating solution and method of use
AssigneeOMG Americas, Inc.
InventorsAnthony M Piano, James Trainor
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Abstract
An electroless palladium plating solution includes a polar solvent, at least one palladium salt, at least one non-nitrogenated complexing agent, an alkaline adjusting agent that adjusts the plating solution to a pH of at least 8.0, and a reducing agent. The plating solution, which is used for forming a layer of palladium on a surface of a substrate, yields a substantially pure palladium deposit on the substrate. Precipitation of reduced palladium in the plating solution is substantially prevented.
Claims20
An electroless plating solution comprising:
- a polar solvent;
- at least one palladium salt;
- at least one non-nitrogenated complexing agent;
- an alkaline adjusting agent, wherein the adjusting agent adjusts the plating solution to a pH of at least 8.0;
- and
- a reducing agent.
A method of forming a layer of palladium on a surface of an article, the method comprising the steps of:
- providing an article having a metal surface, wherein the article is selected from the group consisting of a circuit board, a microelectrode and an electronic component;
- providing a working bath comprising a palladium salt at a pH of greater than 8.0;
- providing at least one non-nitrogenated complexing agent selected from the group consisting of sodium citrate, ammonium citrate, sodium malate, sodium phenol sulfonate, sodium tartrate, and potassium sodium tartrate;
- reducing the palladium from the bath by providing a reducing agent;
- and
- contacting the metal surface to the bath such that a layer of palladium is formed on at least a portion of the metal surface.
The method of 13, wherein the salt of formic acid is sodium formate.
An electroless plating solution comprising:
- water;
- palladium sulfate;
- ammonium citrate;
- ammonium hydroxide, wherein the ammonium hydroxide adjusts the plating solution to a pH of at least 8.0;
- sodium phenol sulfonate;
- and
- sodium formate.
Dependencies are inferred from the claim text.