K. Kragler et al., SCANNING-TUNNELING-MICROSCOPY BASED LITHOGRAPHY EMPLOYING AMORPHOUS HYDROGENATED CARBON AS A HIGH-RESOLUTION RESIST MASK, Applied physics letters, 67(8), 1995, pp. 1163-1165
Amorphous hydrogenated carbon (a-C:H) is introduced as a constituent o
f a two-layer resist system for lithography with a scanning tunneling
microscope (STM) operating in air. The resist is made up of a thin ele
ctron sensitive and chemically amplified top resist (less than or equa
l to 50 nm) and a-C:H as a thick conducting and etchable bottom resist
. In this setup the bottom resist acts as the counter electrode allowi
ng in principle operation on insulating substrates. We show that it is
possible to generate structures with high aspect ratios by transferin
g the developed top resist patterns by means of oxygen reactive ion et
ching (RIE) into the bottom resist and halogen RIE into silicon substr
ates. Linewidths between 100 and 50 nm have been observed in the botto
m resist as well as in the substrates. (C) 1995 American Institute of
Physics.