Experimenting and modeling of catastrophic failure in electromigration-induced resistance degradation for deep submicron dual-damascene copper interconnects

Atomic drift-less electromigration model for submicron copper interconnects

“…Voiding is the obvious effect of directional mass-transport from cathode side to anode side due to EM. The entire process of void growth phenomenon is well explained and verified by experiments [3,[26][27]. Recently, for submicron Cu dual-damascene interconnects, the process of void growth is established by Adhikari et al [26] and similar void growth process is considered in this work.…”

“…The entire process of void growth phenomenon is well explained and verified by experiments [3,[26][27]. Recently, for submicron Cu dual-damascene interconnects, the process of void growth is established by Adhikari et al [26] and similar void growth process is considered in this work. A schematic of the void growth process considered in this work is portrayed in Figure 1.…”

“…The instantaneous ratio of void length to that of thickness is represented by the symbol β (in Figure 1) and it is termed as the shape parameter. Next, based on the above-mentioned voiding process, we have formulated the resistance change profile as a function of void volume [26]. However, correlating resistance change profile with time, stress conditions, line geometry, microstructure etc.…”

“…The effect of barrier (or liner) is ignored and hence, the resistance increases mainly due to the voiding Cu near the cathode. Thus, the resistance change behaviour of interconnect under EM stressing is simply given by [26]…”

“…On the other hand, when the void expands more in the vertical direction than that of lateral direction, then catastrophic failure occurs. Readers are referred to the reference [26] and the references there in for substantial experimental evidences in favour of these experimental observations.…”