Tracking the cross-linking mechanism of a metal-organic EUV photoresist using GISAXS

Extreme ultraviolet (EUV) lithography has entered high-volume manufacturing enabling the production of integrated circuits with few tens of nanometer sized features on wafers. However, the exposure mechanism of EUV photoresists is still not completely understood, which will limit the advancement for future technology nodes. Employing Grazing Incidence Small Angle X-Ray Scattering at the DUBBLE beamline we want to track and quantify the cross-linking of model tin-oxo cage photoresists upon EUV exposure by determining the particle size of resist thin films exposed at different doses and which have undergone different processing conditions. The particle (or unit) size of the cross-linked structure is a fundamental parameter that is linked to the spatial limit at which features can be printed in a photoresist. Resolving the evolution of the unit size during lithographic processing is critical for designing the highest resolution photoresist materials.