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EBID – innovative
nanostructuring
technology
Experiments in size-reducing electron
projection (Tübingen in 1971, Darmstadt
in 1984) made it clear that the
desired high resolution in electron
beam lithography could only be
achieved with a loss of sensitivity of
the registration procedure. The highest
resolution can be achieved when
small molecules are used for registration
by means of direct metallization
deposition. The EBID (Electron Beam
Induced Deposition) nanostructuring
technology involves directing a jet of
organo-metallic molecules onto the
substrate in a vacuum. The molecules
adsorbed in the substrate are then
decomposed by an electron beam
that is focused to a diameter of just a
few nanometers, thus delivering an
energy density of up to 2 MW/cm 2 .
Organometallic
molecules
or etching
gas
Evaporating
radicals
Innovation 16, Carl Zeiss AG, 2005
Jet
Mask
Within a few minutes, 3-dimensional
deposition products then grow from
the molecular fragments and atoms.
Since molecules are used individually,
the procedure is 1 million times slower
than conventional resist electron
beam lithography.
Nanostructuring was studied by
means of direct-write using single
beam lithography at the IBM T. J.
Watson Research Center in the USA,
and by electron shadow projection
and size-reducing electron projection
at the Technical University of Darmstadt,
Germany. The technique of
electron shadow projection has since
become known as EPL (Electron Projection
Lithography). Other fundamental
investigations and initial applications,
such as single beam deposition
and etching procedures, were
carried out at the Deutsche Telekom
Research Center, FTZ.
Electron beam
Etch dip
Residual gas
Deposit Adsorbed
molecules
2
special
Rapid prototyping
using EBID
Rapid prototyping procedures are
fabrication processes used to directly
and rapidly implement existing
design data to produce workpieces
with as little manual handling as
possible. The procedures that have
become known as rapid prototyping
since the 1980s are usually master
molding methods that use physical
and/or chemical effects to build
up the workpiece in layers from
materials that have no shape or are
neutral in shape.
Starting in the fall of 1997, a
research team at Deutsche Telekom
AG commissioned by USA-based
Corning Inc. developed a rapid
prototyping technology for spectral
filters based on photonic crystals.
Photonic crystals are 3-dimensional,
periodical, dielectric structures built
up using the EBID technique which
consist of rods with diameters of 1/5
of the wavelength that are arranged
at a distance of 1/3 of the wavelength
from each other. A PC filter
for infrared light with a wavelength
of 1.5 µm such as used in telecommunications
needs to consist of
approx. eighty 0.3 µm x 2 µm rods
that are spaced at 0.5 µm intervals
and made of a material with the
highest possible refractive index
(n > 2.8). The team developed and
patented the production of photonic
crystals (PC) and other miniaturized
planar optical components using
EBID technology. Spectral filters
(3 µm x 3 µm) were fabricated in as
little as 40 minutes and proved to
have nanometer precision in waveguide
measuring structures.
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