Outer lead for a semiconductor IC package and a method of fabricating the same
AssigneeNgk Spark Plug Co., Ltd.
InventorsKazuhisa Sato, Kazuo Kimura
Life of this patent
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Abstract
An outer lead having a plurality of external leads 1 for electrically connecting the semiconductor IC of a semiconductor IC package to external devices comprises a base plate 11, a plated base structure formed over the surface of the base plate 11 and consisting of a plurality of plated base layers 12, 13 and 14 of Ni or a Ni alloy, and a surface layer 15 of Au or an Au alloy formed over the uppermost plated base layer 14 of the plated base structure. The number of the plated base layers is at least three. Each plated base layer 12, 13 and 14 of the plated base structure is subjected to crystal-growth annealing after being formed by plating to crystal-grow the grains thereof. A method of fabricating such an outer lead is provided.
Claims20
A method of fabricating an outer lead for a semiconductor IC package, comprising:
- providing a base plate having at least one surface;
- forming a first plated base layer over the surface of the base plate by plating;
- crystal-growing the grains of the first plated base layer by heat treatment;
- forming a second plated base layer over the heat treated first plated base layer by plating;
- crystal-growing the grains of the second plated base layer by heat treatment;
- forming a third plated base layer over the heat treated second plated base layer by plating;
- crystal-growing the grains of the third plated base layer by heat treatment;
- and
- forming a surface layer over the heat treated third plated base layer by plating.
A method of fabricating an outer lead for a semiconductor IC package, comprising:
- providing a base plate having at least one surface;
- forming a plated base layer over the surface of said base plate by plating;
- heat treating said plated base layer;
- repeating said forming and said heat treating so that a plurality of heat treated plated base layers laid one upon another are formed on said base plate;
- and
- forming a surface layer over said plurality of heat treated plated base layers by plating.
A method of fabricating a semiconductor IC package having at least one outer lead, comprising:
- providing an IC package with an outer lead base plate, said outer lead base plate having at least one surface;
- forming a plated base layer over the surface of said outer lead base plate by plating;
- heat treating said plated base layer;
- repeating said forming and said heat treating so that a plurality of heat treated base layers laid one upon another are formed on said outer lead base plate;
- and
- forming a surface layer over said plurality of heat treated plated base layers by plating.
Dependencies are inferred from the claim text.