Pattern transfer of electron beam modified self-assembled monolayers for high-resolution lithography

Self-assembled monolayers of octadecylsiloxane and octadecylthiol have been modified by high-resolution electron beam lithography. Focused electron beams from 1 to 50 keV and scanning tunneling microscopy at approx.10 eV have been used as patterning tools. The patterns have been transferred into many substrates by wet, dry, and combinations of wet and dry etches. Wet etching almost always results in a positive tone, but reactive ion etching of GaAs with Cl₂ at very low dc biases (<10 V) results in a negative tone. The effect of electron beam damage on the monolayers and the subsequent etching reactions has been explored through x-ray photoelectron spectroscopy.