Abstract

Resists used for soft x-ray projection lithography must achieve high resolution and exhibit both high sensitivity and reasonable exposure latitude. Additionally, to prevent the deposition of highly-absorbing molecular species on multilayer-coated reflective optics, photon-induced desorption from the resist must be minimized. Chemically amplified resists show promise, exhibiting excellent sensitivity and resolution for e-beam and keV x-ray exposures[1-4], although they have not yet been characterized at wavelengths appropriate to soft x-ray projection lithography (SXPL). One often-noted issue regarding these resists is that the diffusion length of the photogenerated catalysts may limit their ultimate resolution[4]. Characterization of the diffusion length, and its dependence on the post-exposure bake temperature, has not been performed at SXPL wavelengths, however. Lastly, the beam-induced evolution of neutral and ionic molecular species from resists is a well-known phenomenon [5], although such desorption has not been studied for incident extreme ultraviolet (XUV) and soft x-ray radiation.

© 1992 Optical Society of America