Holistic approach using accuracy of diffraction-based integrated metrology to improve on-product performance, reduce cycle time and cost at litho

High-end semiconductor lithography requirements for CD, focus and overlay control drive the need for diffraction-based metrology(1,2,3,4) and integrated metrology(5). In the advanced nodes, more complex lithography techniques (such as multiple patterning), use of multi-layer overlay measurements in process control, advanced device designs (such as advanced FinFET), as well as advanced materials (like hardmasks) are introduced. These pose new challenges for lithometro cycle time, cost, process control and metrology accuracy. In this publication a holistic approach is taken to face these challenges via a novel target design, a brand new implementation of multi-layer overlay measurement capability in diffraction-based mode and integrated metrology.