Optimization of Ion Implanter Hardware for Metal Contamination Reduction

Metal contamination control is one of the most critical performance for ion implantation process, and any metal contamination introduced to junction will induce leakage current and device performance degradation. With CMOS technology developing, more and more aggressive requirements for metal contamination control of ion implantation process has been brought up, especially for CMOS image sensor product. In this work, metal contamination performance was evaluated for 300mm high current ion implantation tool. Experiments were designed to locate the metal contamination source for wafer mechanical transfer and on-beam process separately. Dedicated hardware modification was proposed and performed according to the results analysis. And after tool modification, the metal contamination, particle and SIMS-matching were characterized to evaluate its influence on ion implantation process. From the measured data, conclusion can be made that the metal contamination performance was greatly improved without any process performance degradation after hardware modification.