Resist performance in 5nm and 13nm soft X-ray projection lithography

Imaging experiments in 5nm and 13nm soft X-ray projection lithography (SXPL) were performed using two separate 32:1 reduction Schwarzschild optics with a Ni/CrC multilayer and a Mo/Si multilayer, respectively. The optics were illuminated with synchrotron radiation (SR) light source from the SORTEC ring. Sensitivities of [email protected] PMMA and ZEP are 285 and 34mJ/cm^2 at 5nm and those of [email protected] PMMA and ZEP are 134 and 38mJ/cm^2 at 13nm. Resist contrasts (@c-values) of [email protected] PMMA and ZEP are 2.5 and 1.6 at 5nm, and those of [email protected] PMMA and ZEP are 1.8 and 1.4 at 13nm. A [email protected] pattern can be replicated by 13nm exposure, while only just a [email protected] pattern can be replicated by 5nm exposure. The high resolution of [email protected] at 13nm is limited by diffraction, while that of [email protected] at 5nm is limited by the wavefront error of the multilayer-coated optics.