Thermal scanning probe lithography

Scientists around Daniel Rugar and John Mamin at the IBM research laboratories in Almaden have been the pioneers in using heated AFM (atomic force microscope) probes for the modification of surfaces.

In 1992, they used microsecond laser pulses to heat AFM tips to write indents as small as 150 nm into the polymer PMMA at rates of 100 kHz.

[6][7] This thermo-mechanical data storage concept formed the basis of the Millipede project which was initialized by Peter Vettiger and Gerd Binnig at the IBM Research laboratories Zurich in 1995.

Such local evaporation of resist induced by a heated tip could be achieved for several materials like pentaerythritol tetranitrate,[9] cross-linked polycarbonates,[10] and Diels-Alder polymers.

[17] The integrated heaters enable in-situ metrology of the written patterns, allowing feedback control,[18] field stitching without the use of alignment markers[19] and using pre-patterned structures as reference for sub-5 nm overlay.