Experimental investigation of the formation of nano-indentations on thin polymer films

The 4th International Conference on Micro-Nanoelectronics, Nanotechnologies and MEMs, Athens, Greece, December 12-15, 2010.

Abstract: Scanning probes with nanometer-sharp tips have been used extensively the last few years for imaging and altering materials down at the nanoscale. Representative applications that use such techniques are nanolithography, nanopatterning and ultra-high-density data storage. The final formation of the material may vary significantly from the expected shape due to the motion of the tip and to the fact that material formation takes a short but considerable amount of time to be completed. In most ultra-high-density probe-based data storage systems, information is stored in the form of nano-indentations on thin polymer films. The shape of these indentations affects the accuracy of detecting the stored information, especially at high readback data rates. In this work, we experimentally investigate the effect of nanopositioning speed on the formation of nano-indentations on thin polymer films coated on a silicon wafer substrate. For the formation and fine 3-D imaging reconstruction of the nano-indentations an Atomic Force Microscope (AFM) based experimental set-up is used. The set-up comprises a piezo-actuated nanopositioner capable of nanometer-precise positioning of the polymer medium relative to a cantilever with integrated heaters for locally heating the polymer, as well as an optics stack for fast reading and high resolution imaging. First results demonstrate the way the 3-D shape and quality of the engraved indentations depend on the linear velocity of the nanopositioner motion used during the formation process. Additionally, based on the experimental data, a parametrical mathematical model is extracted, which is capable of capturing the three dimensional nano-indentation shape as well as its variants as a function of nanopositioning speed.

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