EFFECTS OF PHOTO-ELECTRON AND AUGER-ELECTRON SCATTERING ON RESOLUTION AND LINEWIDTH CONTROL IN SR LITHOGRAPHY

The effects of photo- and Auger electron scattering on resolution and linewidth control in X-ray lithography are quantitatively evaluated employing resist patterns replicated using a novel contact replication method. In this method, the effects of penumbral shadow and Fresnel diffraction can be neglected because exposure, development and SEM observation are carried out keeping the absorber pattern on the resist. The depth of the undercut of the resist pattern from the absorber pattern edge, which means the range of electron scattering in the lateral direction, increases from zero to the Bethe range as a function of exposure dose, and reaches 0.16 µm in SR lithography with spectra ranging from 0.2 to 1.4 nm. It is shown that the maximum range of photo- and Auger electron scattering does not determine the resolution directly, but rather affects the linewidth control. © 1990 IOP Publishing Ltd.