Electroless palladium plating liquid
View Patent ↗An electroless palladium plating liquid, with excellent bath stability, that can provide a film with excellent corrosion resistance, solder bondability, and wire bondability is provided. The invention is an electroless palladium plating liquid, containing: a water soluble palladium compound; at least one of ammonia, an amine compound, an aminocarboxylic acid compound, and carboxylic acid as a complexing agent; and bismuth or a bismuth compound as a stabilizer. Preferably the electroless palladium plating liquid further contains at least one of hypophosphorous acid, phosphorous acid, formic acid, acetic acid, hydrazine, a boron hydride compound, an amine borane compound, and salts thereof as a reducing agent.
1. An electroless palladium plating liquid, comprising:
a water-soluble palladium compound containing palladium as the sole metal to be plated;
at least one of ammonia, an amine compound, an aminocarboxylic acid compound and a carboxylic acid as a complexing agent; and
bismuth or a bismuth compound as a stabilizer.
2. The electroless palladium plating liquid according to claim 1 , further comprising at least one of hypophosphorous acid, phosphorous acid, formic acid, acetic acid, hydrazine, a boron hydride compound, an amine borane compound, and salts thereof, as a reducing agent.
3. A palladium plated article comprising a palladium layer formed from the electroless palladium plating liquid of claim 1 , provided between an electroless nickel plating layer and an electroless gold plating layer, the plated article having a discoloration of less than 1% in a corrosion resistance test.
4. A method of forming an electroless palladium plating on an article comprising a step of immersing the article in the electroless palladium plating liquid of claim 1 .