IMMERSION TIN SILVER PLATING IN ELECTRONICS MANUFACTURE

摘要

A method is provided for depositing a whisker resistant tin-based coating layer on a surface of a copper substrate. The method is useful for preparing an article comprising a copper substrate having a surface; and a tin-based coating layer on the surface of the substrate, wherein the tin-based coating layer has a thickness between 0.5 micrometers and 1.5 micrometers and has a resistance to formation of copper-tin intermetallics, wherein said resistance to formation of copper-tin intermetallics is characterized in that, upon exposure of the article to at least seven heating and cooling cycles in which each cycle comprises subjecting the article to a temperature of at least 217°C followed by cooling to a temperature between about 20°C and about 28°C, there remains a region of the tin coating layer that is free of copper that is at least 0.25 micrometers thick.