Small particle defect characterization on critical layers of 22nm Spacer Self-Aligned Double Patterning (SADP)

The 22nm Spacer Self Aligned Double Patterning (SADP) process developed at Applied Materials' Maydan Technology Center was used to characterize small particle defects in the four critical steps of the process flow: Lithography, APF Etch, Spacer Deposition, Spacer Open. Small Particle defect contamination poses a risk to yield in each of the SADP process steps (Lithography, Deposition and Etch) and requires an understanding of their sources and impact on each subsequent step. The defect inspection was carried out using two different inspection platforms; DFinder (TM) which is designed for detection of 3D defects and UVision (TM) 3 which is designed for detection of 2D defects. Small particle defects (smaller than 60nm), in the Lithography and APF Etch process steps were shown to become "killer" defects at the Spacer Open step. More study is needed to develop inspection strategies based on a wider range of defect types.