SEM based automatic defect classification (ADC)

Automatic defect classification (ADC) on the optical defect detection and review tools have found increasing acceptance in the cleanroom for defect reduction during all phases of yield learning (process R&D, yield ramp and mature production). However at 180nm technology node, the optical tools are unable to classify the smaller defects of interest. SEM based ADC tools provide this capability through high resolution imaging and classification ((1)). This paper will provide an overview of past and future yield learning trends and challenges, role of ADC in the yield learning process and a detailed review of the SEM based ADC tool evaluation project conducted at SEMATECH during 1997/1998 which yielded the following beta results at a SEMATECH member company fab.