Noncontact nanolithography using the atomic force microscope

We have demonstrated that the atomic force microscope (AFM) operating in air may be used to pattern narrow features in resist in a noncontact lithography mode. A micromachined AFM cantilever with an integrated silicon probe tip acts as a source of electrons. The field emission current from the tip is sensitive to the tip-to-sample spacing and is used as the feedback signal to control this spacing. Feature sizes below 30 nm have been patterned in 65-nm-thick resist and transferred through reactive ion etching into the silicon substrate. We show that the same AFM probe used for noncontact patterning can be used to image the sample. In addition to eliminating the problem of tip wear, this noncontact system is easily adapted to multiple-tip arrays where each cantilever has an integrated actuator to adjust the probe height. (C) 1998 American Institute of Physics. [S0003-6951(98)04643-9].