WAFER-LEVEL INTERCONNECT FOR HIGH MECHANICAL RELIABILITY APPLICATIONS

摘要

The structure described herein incorporates an interconnect positioned between two spaced electrical contacts. The interconnect comprises a lead (Pb)-free solder alloy consisting essentially of nickel (Ni), tin (Sn), silver (Ag), and copper (Cu). The nickel (Ni) content is sufficient to produce a smooth interfacial IMC layer in an under bump metallurgy (UBM) when disposed between the two contacts. An embodiment of the structure described herein is a device comprising a substrate, an under bump metallurgy (UBM) disposed on the substrate, a bulk solder body disposed on the under bump metallurgy (UBM), and a wafer device connected to the under bump metallurgy (UBM) through the bulk solder body. The bulk solder body comprises of nickel (Ni), tin (Sn), silver (Ag), and copper (Cu). The nickel (Ni) is in a range of 0.01 to 0.20 percent by weight (wt%).