Abstract: The invention provides a technique and a device that dramatically improve joint reliability of miniature joints of fine electronic components. According to the invention, when producing a tin or a solder alloy used for electronic components, an ingot of a tin or a solder alloy is heated, melted and delivered to a reactor. Also, a solution containing organic acid having a carboxyl group (—COOH) is delivered to the reactor. After stirring and mixing the two liquids intensively, the mixed liquid is separated into a molten tin or a molten solder alloy liquid and an organic acid solution according to the difference in specific gravity. Then, the respective liquids are circulated to the reactor, and the metal oxides and the impurities existing in the molten tin or the molten solder alloy are removed, and the molten tin or the molten alloy is purified to have oxygen concentration of 5 ppm or less.

Abstract: A tin or solder alloy film is formed by ejecting molten tin liquid or molten solder alloy liquid in a jet state onto a copper surface of an electronic component. The overflowing molten tin or molten solder alloy liquid is transported to a stirrer. Then, cuprate and the like mixed in the overflowing molten tin or molten solder alloy liquid are taken in to the organic fatty acid solution by fiercely stirring and mixing the molten tin or molten solder alloy liquid in contact with a solution at a temperature of 180 to 350° C. containing 1 to 80 weight % of organic fatty acid having 12 to 20 carbon number that circulates in the stirrer to purify the overflowing molten tin or molten solder alloy liquid.