Noncontact nanolithography using the atomic force microscope

Abstract

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.

Modeling near-field radiative heat transfer from sharp objects using a general three-dimensional numerical scattering technique

“…Our work is motivated by studies of non-contact thermal writing with a hot, sharp object [1,2]. Theory has predicted [3,4] and experiments have confirmed [5,6] that radiative heat transfer between two bodies at different temperatures is greatly enhanced as their separation is reduced to sub-micron scales, due to contributions from evanescent waves.…”

“…In order to examine this, we envision a scenario in which a critical magnitude of the z-directed Poynting flux is required in order for some change to occur on the plate, for example, the patterning of a thermal mask for later etching [2]. Figure 2 plots the Poynting flux at x = 0 as a function of z, which will tell us how far away the object must be before it can effect this patterning.…”

Nanolithography Study Using Scanning Probe Microscope

“…Manipulating surfaces, creating atomic assembly, fabricating chemical patterns and characterizing various mechanical properties of materials in nanometer regime are enabled by this technique (Hyon et al, 1999;Sadegh Hassani & Sobat, 2011;Bouchiat & Esteve, 1996). Nanolithography with AFM is also a tool to fabricate nanometer-scale structures with at least one lateral dimension between the size of an individual atom and approximately 100 nm on silicon or other surfaces (Wilder & Quate, 1998). This technique is used during the fabrication of leading edge semiconductor integrated circuits (Sugimura & Nakagiri, 1997) or nanoelectromechanical systems (NEMS).…”

Multi-Functional Probe Recording: Field-Induced Recording and Near-Field Optical Readout

“…In order to minimize damage to both the tip and sample during the recording, we introduce a noncontact AFM configuration. This allows us to locally heat the Au surface using the field-emission current [6] from the sharp and hard W 2 C coated tip and to manipulate the Au atoms or clusters without a mass transfer between the tip and sample [7], [8]. The recorded marks are then optically read out by using NSOM probes with a 100-nm spatial resolution.…”