Sub-20 nm x-ray nanolithography using conventional mask technologies on monochromatized synchrotron radiation

The optimal wavelength range for x-ray lithography is usually estimated between 0.8 and 1.4 nm. In this work, the use of a monochromator working at 1.1 nm on synchrotron radiation is reported. Replication results in this monochromatic mode are compared with results obtained for a polychromatic synchrotron radiation centered at 0.8 nm in terms of resolution and image contrast, Two conventional mask technologies are used for this study. The influence of the mask contrast is also studied. A nondestructive soft contact system was chosen to lower the gap below 1 mu m. An ultimate resolution of 20 nm is shown in PMMA resist as well as 35 nm in PMMA/MAA (8.5%) resist for the monochromatic mode. The effect of photoelectrons created in the substrate is also investigated by replications on Si substrates coated with a Cr/Au bilayer. In addition, the daughtering of high resolution masks at 1.1 nm is successfully performed in the 20 nm range by Au electroplating. (C) 1997 American Vacuum Society.