Hybrid approach to optical CD metrology of directed self-assembly lithography

Directed Self Assembly (DSA) for contact layers is a challenging process in need of reliable metrology for tight process control. Key parameters of interest are guide CD, polymer CD, and residual polymer thickness at the bottom of the guide cavity. We show that Optical CD (OCD) provides the needed performance for DSA contact metrology. The measurement, done with a multi-channel spectroscopic reflectometry (SR) system, is enhanced through elements of a Holistic Metrology approach such as Injection and Hybrid Metrology.