Feasibility of measuring four profile parameters for metal-0 trench of DRAM by spectroscopic ellipsometry based profile technology

The feasibility of measuring four profile parameters, i.e,, total etch depth, critical dimension (CD), thickness of remaining poly hard mask, and sidewall angle, for the metal-0 trench of DRAM by a single technique was investigated in this study. Broadband spectroscopic ellipsometry was used to provide non-destructive profile information. The results prove its capability for providing the required profile information, traditionally measured on 4 different metrology tools, by a single measurement. This capability could significantly simplify the process flow for metal-0 trench.