Latch-Up Induced Slit Voiding in Aluminum Metal Lines

Latch-up induced during High Temperature Operating Life (HTOL) test of a mixed signal device fabricated with 1.0 μm CMOS, double poly, double metal process caused failures due to an open in aluminum metal line. Metal lines revealed wedge voids of about 50% of the line width. Triggering of latch up mechanism during the HTOL test resulted in a several fold increase of current flowing through the ground metal line. This increase in current resulted in the growth of the wedge voids leading to failures due to open metal lines.