GOLD PLATING METHOD FOR BURN-IN SOCKET

摘要

PROBLEM TO BE SOLVED: To lessen the increase in the contact resistance of terminal parts in spite of repetition of burn-in tests and to diminish the insertion force of a semiconductor element into a socket by consisting the above material of an intermediate layer of alloy plating containing a specific ratio of P in a base metal of Cu or Cu alloy and consisting of the balance Ni or Ni and Co and an Au or Au alloy plating surface layer and imparting high heat resistance and good inserting and removing properties to the material. SOLUTION: The content of P in the intermediate layer of the plating material is specified to 0.05 to 20 wt.%. The intermediate layer preferably contains >=1 kinds among Cu, Zn and Sn at 10 to 60 wt.% in total in addition to P. Further, these elements are added to the material according to the case that a pressing property is desired to be improved by lowering the hardness of Ni-P, Ni-Co-P plating films. The intermediate layer may further preferably contains 0.05 to 20 wt.% B. The thickness of the intermediate layer is specified to >=0.3μm in terms of heat resistance and is preferably specified to <=3μm in terms of the pressing property. The thickness of the surface layer is specified to >=0.05μm in order to maintain the low contact resistance and is preferably specified to <=2μm in terms of a production cost.