“…Cu could be one of the most promising candidates for low cost electrically conductive fillers, due to its low resistivity, low cost, and reduced electromigration compared to Ag (36,138). Other low cost electrically conductive fillers have also been developed to replace Ag for ICAs, including solder particles (59,139), a mixture of solder and Cu (59), Cu alloys (57,140,141), Cu coated with a thin layer of low melting point metals, Pb-free metals (such as Sn, In, Bi, Sb, Zn, and their alloys) (62), and Ag-coated Cu fillers (37)(38)(39)(141)(142)(143). The challenge associated with ICAs filled with the low cost conductive fillers lies in the oxidation and corrosion of the filler particles during curing and reliability tests.…”