At moderate and high electric wind intensities, χ=25 −50 , the almost cylindrical in shape and small in size internal void forms, which slowly drifts towards the cathode end of the sample as illustrated in Figure. The size of these internal voids seems to be inversely proportional with the electron wind intensities. There is also strong tendency for the formation of multiple voids popping out from the same source, namely from the edge void, which may act as an continuous source up to certain extent. The incubation times for the creation of EM voids strongly depend on the applied electric field. At high electric fields, such as X=50, the small size void forms with relatively short incubation time. For the moderate electron wind intensities, the incubation time for the void creation becomes longer. At low electron wind intensities , a close observation shows that during long the incubation period, the slit like void embryo grows steadily, and finally detached from the mother edge-void, reaches the lower surface of the interconnect and causes fatal failure.