Composite copper nickel alloys with improved solderability shelf life
AssigneeOlin Corporation
InventorsJulius C. Fister, John F. Breedis
Life of this patent
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Abstract
A composite structure having improved solderability shelf life and contact resistance is formed by coating a copper alloy substrate material with a tin-containing material. The copper alloy substrate material consists essentially of about 15% to about 30% nickel and the balance essentially copper. The copper alloy may further include up to about 25% zinc. The nickel in the alloy retards the growth of copper-tin and/or copper-zinc-tin intermetallic compounds and the diffusion of the copper through the coating. The coating may be formed from tin or tin alloys including tin solders, e.g. 60% Tin-40% lead solder.
Claims15
A composite structure having a reduced growth of copper-tin intermetallic compounds, said composite structure comprising:
- a substrate formed from a copper base alloy;
- said copper base alloy consisting essentially of 19% to about 28% nickel and the balance essentially copper;
- a coating covering at least a portion of said substrate;
- said coating being formed from a tin-containing material;
- and
- said nickel in said alloy retarding the growth of said copper-tin intermetallic compounds and diffusion of said copper through said coating and thereby improving the solderability shelf life and contact resistance of said structure.
An integrated circuit assembly for electrical applications, said assembly comprising:
- a lead frame formed from a composite structure;
- said composite structure having a substrate formed from a copper alloy consisting essentially of 19% to about 28% nickel and the balance essentially copper and a coating covering at least a portion of said substrate;
- said coating being formed from a tin-containing material;
- and
- said nickel in said alloy retarding the growth of copper-tin intermetallic compounds and diffusion of said copper through said coating.
Dependencies are inferred from the claim text.