Effect of pulsed plasma, pressure, and RF bias on electron shading damage

The electron shading damage mechanism as proposed by Hashimoto has been widely accepted as the major charge damage mechanism for the current device generation. Vahedi et al derived an analytic model that clarifies the contribution of plasma and device parameters in topography induced charging. The effects predicted by the analytic model have been verified by our previous work. This continuation of the work examines the role of plasma parameters on V_th-shifts in transistors fabricated with a Flash memory process where metal 1 was etched in a Lam TCP^TM 9600 PTX chamber. The roles of low pressure, RF bias, and pulsed plasmas in reducing damage were investigated using these antenna device wafers. Initial results appeared to contradict analytic mode predictions, but investigation of the topography changes during etch eliminated the contradictions and is leading to work on a refined analytic model taking dynamic effects into consideration