Sn-PLATED COPPER SUBSTRATE, METHOD FOR MANUFACTURING Sn-PLATED COPPER SUBSTRATE, LEAD FRAME USING THE SAME, AND CONNECTOR TERMINAL

摘要

PROBLEM TO BE SOLVED: To provide an Sn-plated copper substrate which has a plated layer that hardly forms whisker even when an external stress is applied thereto and can be stably formed, is superior in solderability and does not include Pb.

SOLUTION: The Sn-plated copper substrate 1 has at least one plated film layer 5 formed by stacking an intermediate Sn-plated layer 3IL and a Cu-plated layer 4 in this order on any metal substrate 2 of a pure copper sheet, a copper alloy sheet and a copper-plated metal sheet, so as to have a layer thickness of 1.5μm or more; also has an outermost Sn-plated layer 3OL on the plated film layer 5 so that the layer thickness is 0.2 to 1.5μm and a total thickness including the plated film layer 5 is 3μm or more; and has an Sn-Cu alloy phase 6 which is made by diffusing Cu that originates in at least one of the Cu-plated layer 4 and the metal substrate 2, into at least any of a grain boundary 3g and a grain 3c of the intermediate Sn-plated layer 3IL and the outermost Sn-plated layer 3OL.

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