Custom Wafer Dose Patterning for Automated Process Control in Semiconductor Device Fabrication

VIISta ion implanters now offer a combination of nonuniform dose implantation (SuperScan 3) and advanced process control (APC) capabilities, which enables delivery of custom doses and/or patterns tailored to the individual wafer in a production environment. The APC implementation allows changing dose patterns without retuning the beam, thus minimizing the transition time between dose map changes. By implementing nonuniform mapping implants with APC in DRAM device fabrication, SK hynix has achieved significant improvement in within-wafer uniformity of peripheral-transistor on-current (I_on) and cell transistor threshold voltage (V_t).