Producer BARC open challenges and the baseline set up for FinFET

Multiple Vt tuning is necessary for SOC (system-on-a-chip) FinFET devices at 16nm technology node and beyond. To achieve this, BARC open, as a mask, for NMOS/PMOS implantation process is needed. Vertical profile with enough PR effective height is the key challenge of this process. Besides, WPH for run cost reduction is another major consideration from customer perspective. So gas N2/NH3 chemistry is adopted for its high etch rate, and thus high throughput. For this recipe to get a good etch uniformity on blanket wafer first to ensure good performance on the whole pattern wafer, each parameter was studied, that is, bias power, pressure, NH3 flow, N2 low, FRC, gap, and backside helium pressure. Finally, etch rate >1000A/min with good uniformity <;4% on blanket BARC wafer was got using optimized bias power and gap. Results on pattern wafer show performance is almost acceptable, it is near to vertical and PR effective height is enough.