Effective Epi process window monitoring by high resolution massive CDU metrology: Topic: AM (Advanced metrology)

Advanced technology with shrinking design rules and increasing multi-patterning steps introduce challenging process tolerances. Process marginality is in the form of Edge Placement Errors (EPE), Line Edge Roughness (LER), Line Width Roughness (LWR), Overlay and process induced pattern defects. Advanced metrology and monitoring techniques are needed to trace process induced critical pattern distortion within die, field and wafer. Massive sampling of critical pattern features (i.e. hot spots) measurements can be the solution for tight process margins monitoring. Many measurements across die, field and wafer can reveal clear signature of the process tools from film deposition, lithography, etch, chemical mechanical polishing and epitaxial growth indicate immerging process window marginality issues. Clear signature can be built from thousands to millions measurements. High resolution and throughput metrology tool is needed to provide capabilities in critical dimension uniformity (CDU) and overlay shift for Edge Placement Errors. Channel strain in continuous fin pitch reduction introduces new challenges in crystalline epitaxy growth. It is one of the most challenging tasks in process monitoring and control for lateral growth dimension, abnormal growth and shapes. Epi growth monitoring includes many measurement types and defect detection. A study of new monitoring method based on massive hotspot and CDU measurements is introduced. Examples of its implementation in Epitaxial growth module are provided for engineers to make effective actions in time.