In the present method of undertaking a self aligned source etch of a semiconductor
structure, a substrate has oxide thereon. First and second adjacent stacked gate
structures are provided on the substrate. Oxide spacers are provided on the respective
first and second adjacent sides of the first and second gate stacked structures,
and polysilicon spacers are provided on the respective oxide spacers. A self aligned
source etch is undertaken using the gate structures, oxide spacers, and polysilicon
spacers as a mask. The polysilicon spacers are then removed, and metal, for example
cobalt, is provided on the substrate, using the oxide spacers as a mask. A silicidation
step is undertaken to form metal silicide common source line on the substrate.