Overlay metrology performance of dry photoresist towards high-NA EUV lithography

Abstract

In this work, we study the optical overlay metrology performance and impact of an integrated hard mask etch step using the dry resist process with High Numerical Aperture Extreme Ultraviolet Lithography (High NA EUVL)-related thicknesses. Diffraction-based overlay measurements were performed after dry development and integrated hard mask etching for different overlay target designs. The measurement precision for the after-dry development measurement is shown, and the benefits of using integrated hard mask etch overlay metrology with respect to after-dry development are discussed.