Challenges and Opportunities for Optical CD Metrology in Future Lithography Process

Abstract

As the IC industry is progressing towards 32 nm technology, Optical CD metrology will play an important role to help address many challenges in process control. OCD has the unique capability to characterize many critical dimensions in-line for complicated device structures nondestructively. Future process integration requires frequent W2W monitoring and feed forward / feedback control for critical layers. This makes integrated metrology (IM) a key option in process tools, and currently OCD is the only viable option for CD IM. In order to seize these opportunities, many improvements for OCD are need. Optical tools may need to be further optimized for better CD metrology performance. OCD modeling software should be able to model complicated structures and greatly boost ease of use. Furthermore, a well developed IM-SA OCD common platform is needed as the foundation for advanced process and equipment control.