Abstract: The present invention aims to provide an etchant that can provide good deposition of a metal plating such as a nickel plating, despite its acidity, and a method of surface treatment of aluminum or an aluminum alloy using the etchant. Included is an etchant containing a zinc compound and a fluorine compound and having a pH of 4.5 to 6.5.

Abstract: The present invention aims to provide a metal displacement solution that can provide good adhesion to a plating film (metal film), and a method for surface treatment of aluminum or an aluminum alloy using the metal displacement solution. Included is a metal displacement solution which contains a zinc compound, a nickel compound, a germanium compound, and a fluorine compound.

Abstract: The electroless gold plating bath includes a gold sulfate, a thiosulfate, ascorbic acid compounds, and hydrazine compounds, the hydrazine compounds being at least one selected from the group consisting of adipic dihydrazide, propionic hydrazide, hydrazine sulfate, hydrazine monohydrochloride, hydrazine dihydrochloride, hydrazine carbonate, hydrazine monohydrate, sebacic dihydrazide, dodecanediohydrazide, isophthalic dihydrazide, hydrazide, 3-hydro-2-naphtboic hydrazide benzophenone hydrazone, phenylhydrazine, benzylhydrazine monohydrochloride, methylhydrazine sulfate, and isopropylhydrazine hydrochloride.

Abstract: A plating bath at least contains a palladium compound, a reducing agent, a complexing agent, and a stabilizer. The stabilizer is an organic compound in which a divalent sulfur compound is bonded to a compound with a heterocyclic structure, and the organic compound contains neither a thiol group nor a disulfide bond.

Abstract: The present invention provides a bump that can prevent diffusion of a metal used as a base conductive layer of the bump into a surface of an Au layer or an Ag layer. A conductive bump of the present invention is a conductive bump formed on a substrate. The conductive bump comprises, at least in order from the substrate: a base conductive layer; a Pd layer; a Pt layer; and an Au layer or an Ag layer having directly contact with the Pd layer, wherein a diameter of the conductive bump is 20 ?m or less.

Abstract: An object of the present invention is to provide an electroless plating bath having excellent property in plating film deposition without containing halides such as chloride in the electroless plating bath. A halogen-free electroless plating bath of the present invention comprising: a water soluble platinum compound or a water soluble palladium compound, and a reducing agent wherein the water soluble platinum compound is a tetraammine platinum (II) complex salt excluding a halide of the tetraammine platinum (II) complex salt, the water soluble palladium compound is a tetraammine palladium (II) complex salt excluding a halide of the tetraammine palladium (II) complex salt and tetraammine palladium (II) sulfate, the reducing agent is formic acid or its salts, and the electroless plating bath contains no halide as an additive.

Abstract: An object of the present invention is to provide an electroless plating bath having excellent property in plating film deposition without containing halides such as chloride in the electroless plating bath.

Abstract: The present invention provides a bump that can prevent diffusion of a metal used as a base conductive layer of the bump into a surface of an Au layer or an Ag layer. A conductive bump of the present invention is a conductive bump formed on a substrate. The conductive bump comprises, at least in order from the substrate: a base conductive layer; a Pd layer; a Pt layer; and an Au layer or an Ag layer having directly contact with the Pd layer, wherein a diameter of the conductive bump is 20 ?m or less.