Pb-free solder alloy compositions comprising essentially tin(Sn), Silver(Ag), copper(Cu), and phosphorus(P)
AssigneeAoki Laboratories Ltd.
InventorWai Yin Leung
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Abstract
A Pb-free solder alloy based on Sn as matrix is provided, which is a metal that has no toxicity and is environmental friendly. The Pb-free solder comprises a tetra-nary composition consisting essentially of about 99.0 weight % Sn, 0.3 to 0.4 weight % Ag, and 0.6 to 0.7 weight % Cu, with off-eutectic melting temperature of 217 to 227 degree Celsius. The fourth component is a non-metallic phosphorus (P), and 0.01 to 1.0 weight % of phosphorus is added into said composition to improve better micro-structural stability and hence reduce the formation of dross when hand soldering, wave soldering and reflow soldering during the electronic assembly installation process.
Claims12
A Pb-free electrical conductor solder composition consisting essentially of about 0.3 to 0.4 weight % Ag, 0.6 to 0.7 weight % Cu, not more than 1.0 weight % P, balance Sn and unavoidable impurities, based on the weight of composition.
Dependencies are inferred from the claim text.