Aggravated Electromigration of Copper Interconnection Lines in ULSI Devices Due to Crosstalk Noise

In this paper, the impact of crosstalk noise between two adjacent interconnection lines, namely, the aggressor and a victim line, upon electromigration (EM) and Joule-heating failure mechanisms in ULSI microchips has been studied. It was shown that the crosstalk noise leads to distortions of signal waveforms at the far end of the victim line, i.e., the signals supplied to the input of a far-end CMOS inverter. As a result, the shape of the inverter's currents, flowing through the next-stage line (i.e., the line that loads this inverter), is modified in such a way that both EM and Joule heating of the next-stage line are aggravated. The studies reveal that the most deleterious scenario of the crosstalk noise is when the victim and aggressor are switching in opposite directions and the aggressor begins to switch around the trip point of the victim's far-end CMOS inverter (i.e., when both nMOSFET and pMOSFET are open and in a triode mode). Thereby, the crosstalk noise is not only a signal integrity issue as it has been traditionally regarded but also a serious reliability concern that should be taken into account in corresponding reliability models.