• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.62-70
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• 2005

The nanoindenter and AFM have been used for nanofabrication, such as nanolithography, nanowriting, and nanopatterning, as well as measurement of mechanical properties and surface topology. Nanoscale indents can be used as cells for molecular electronics and drug delivery, slots for integration into nanodevices, and defects for tailoring the structure and properties. Therefore, it is very important to make indents of desired morphology (shape, size and depth). Indents of different shapes can be obtained by using indenters of different geometries such as a cube comer and conical and spherical tips. The depth and size of indents can be controlled by making indentations at different indentation loads. However, in case of viscoplastic viscoelastic materials such as polymethylmethacrylate (PMMA) the time dependent deformation (TDD) should also be considered. In this study, the effect of process parameters such as loading rate and hold-time at peak load on the indent morphology (maximum penetration depth, elastic recovery, transient creep recovery, residual depth pile-up height) of PMMA were studied for hyperfine pattern fabrication.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.23-26
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• 2004

Ag/Ni multilayers with different bilayer thickness between 3 and 100 nm produced by DC magnetron puttering have been studied by cross-sectional TEM and nanoindentation. The micrograph shows perfect layered structure with sharp interfaces between Ag and Ni layers. Absolute hardness is calculated as a reference value to compare hardness of specimens regardless of indent depth. A hardness enhancement of nearly $100\%$ over the rule-of-mixtures values, calculated from the measured hardness of single Ag and Ni thin films, is observed. The hardness increases with decreasing bilayer thickness until 8nm. This enhancement shows a good agreement with Hall-Petch relation using grain size (one half of the bilayer thickness) confined within a layer. The deformation behavior can be explained by dislocation pile-up in smaller grains.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.273-276
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• 2008

Thermoplastic resin takes place stress relaxation and creep according to temperature and time. In room temperature, time dependent deformation (TDD) of polymer was carried out at previous study. In this study, it evaluates time dependent deformation to relate temperature. Nanoscale indents can be used as cells for molecular electronics and drug delivery, slots for integration into nanodevices, and defects for tailoring the structure and properties. Therefore, it is important to control pattern depth for change of indent depth by creep when using Nanoindenter. For evaluating TDD at high temperature, it is occurred thermal-nanoindentation test by changing hold time at maximum load. Temperature is putted at $90^{\circ}C$, hold time at maximum loads are putted at 1, 10, 50, 100, 200, 300 and 500s.