Nanolithography
Nanolithography
The technique
of nanolithography is the patterning
of a thin film where the line resolution is
below 100 nm. There are 3 primary techniques that
are used for patterning in
the nanoscale regime.
Electron Beam Lithography
X-ray Lithoraphy
Scanning Probe
Microscopy
An overview of various lithographic
technologies.
Below in Figure 2 is a table that reviews the
various types of lithographic
technologies. The table shows the relative resolution
limits of the various
techniques and the ranges that the various techniques
correspond to.
Figure 2) Table showing the relation between technology
and line width.
The
X-axis is line with in nm. (ref 2)
Challenges in
achieving sub 100 nm electronic devices.
Optical
lithography is
limited by the wavelength of the light used. The UV radiation that is used
has a wavelength
of 193 nm. Lithographic patterns with line resolutions of
120 nm have been obtained in a 1Gbit DRAM chip in
a laboratory situation.
Limitations in line resolution also exist in the photoresist. Figure 3
shows
how existing and new resist technology can be brought together to reduce
line
resolutions to below 100 nm. Currently resist materials that are used in
the
semiconductor industry are polymeric.
Figure 3) Resolution limits obtained
experimentally with Electron beam lithography
and ion beam lithography. (ref 2)