Immersion plating and plated structures
AssigneeInternational Business Machines Corporation
InventorsEmanuel I. Cooper, Charles C. Goldsmith, Stephen Kilpatrick, Carmen M. Mojica, Henry A. Nye, III
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Abstract
A first metal is plated onto a substrate comprising a second metal by immersing the substrate into a bath comprising a compound of the first metal and an organic diluent. The second metal is more electropositive than the first metal. The organic diluent has a boiling point higher than a eutectic point in a phase diagram of the first and second metals. The bath is operated above the eutectic point but below the melting point of the second metal. For example, bismuth is immersion plated onto lead-free tin-based solder balls, and subsequently redistributed by fluxless reflow. Plated structures are also provided.
Claims4
A tin-containing solder having a deposit of plated bismuth tenaciously adhered to a top surface and being alloyed with said tin-containing solder, wherein the amount of bismuth alloyed is about 0.1 to about 0.2% by weight.
Dependencies are inferred from the claim text.