NanoMaker software is based on more than 20-year R&D activity performed
mainly in Institute of Microelectronics Technology RAS.
During this time improvements of e-beam technology processes and setup operating
were developed and implemented in the software in close contact with experimentalists
and technologists (see selected reference list below).
I. Contributions to electron beam lithography
proximity correction, guaranteed accuracy of the correction [1,
2, 8,
11]
Main advantage of the "simple compensation" method developed for
proximity correction in comparison to other correction procedures is its guaranteed
accuracy.
models and simulation methods for development of
positive [4, 5] and negative resists [6]
Simulation of development after exposure allows one to predict result of lithography
with high confidence
3D lithography (3D proximity correction and development) [8,
9, 11,
25]
Special methods and procedures were suggested to fabricate desirable relieves
(shape of resist surface) [8]
with main applications in diffractive optics (calculated holograms, photonic
structure) and cell biology.
direct measurements of proximity parameters [7, 10,
17] (data base of proximity
parameters)
Quality and accuracy of lithography depends on proper value of proximity parameters
[17]. NanoMaker contains a database for the parameters as function of substrate
material and accelerating voltage. The data base were accumulated for several
years as result of special experiments. Difficulty of experimental measurement
is defined by large difference in scale of the parameters (for example beam
diameter (Alpha) belongs to range ten(s) nanometer where as proximity distance
(Beta) is hundreds times larger). Special experimental method (fitting before
measurement) was developed for definition of the proximity parameters [7, 10].
Monte-Carlo calculation of proximity parameters for (arbitrary) layered
media Monte-Carlo method is implemented
to calculate the proximity parameters for
complicated layered substrates, it allows using more precise characterization
of proximity effect. For example depending on resist depth and acceleration
voltage such parameters as Alpha and Eta are different at top and bottom surfaces
of the resist. Effective method for consideration of depth dependence of the
proximity parameter is implemented in the NanoMaker what is very essential at
low energy (e.g. 5 keV) lithography.
II. Software improvements of lithographic machine operation
Much attention and efforts were devoted to elimination of sources and reasons
of accuracy losses of e-beam lithographs.
distortion correction [14]
One of such reasons is distortion (static nonlinear errors in beam position
far from the center of a scanfield). NanoMaker contains special procedures
for distortion compensation during writing. NanoMaker allows one to measure
(to characterize) distortion of a particular SEM (or a lithograph) with a
special procedure as well.
delays compensation [14]
Another source of accuracy loss is delay of beam position on exposed substrate
in comparison to desirable (addressed) value. A special procedure for measurement
of delay parameters of a lithograph is implemented in NanoMaker so NanoMaker
is able to compensate delay errors on "fly" what results to significant
reducing total exposure time and simplifying exposure (blank system now is
not necessary).
control of non-SEM lithographs [12, 13] and hysteresis compensation
in Scanning Probe (AFM) machines.
NanoMaker can control scanning devices of different types for example setup
of focused ion beam [12, 13] and scanning probe microscope. A new type of
errors is found in the latter device, NanoMaker contains a mode for compensation
of hysteresis (long-term temporary distortion) and procedures for hysteresis
parameters definition.
III. Applications of NanoMaker
diffractive optics
Ability to fabricate predisigned relieves based on 3D proximity correction
are using for fabrication of diffractive optics of the highest efficiency
like Fresnell zone plates, kinoform optics and calculated holograms [14, 15].
rainbow holograms for security and against counterfeiting
Exploitation of SEM-based e-beam lithography (NanoMaker) is able dramatically
to reduce cost of rainbow holograms fabrication making the cost comparable to
dot-matrix technique at much higher quality [27].
X-ray diffractive optics
Proximity correction implemented in NanoMaker turned to be very important
for fabrication of high quality X-ray diffractive optics [21, 22]
heating effects
Usage of high throughput e-beam machines with variable beam shape and ultimate
current density can result to temperature increasing at exposure area. Method
for consideration of e-beam heating contribution in exposure dose is developed
[18, 19]. Heating during exposure results to overexposure therefore an approach
for heating effect compensation is suggested [20].
Micro/Nano devices
Some selected examples of microdevices fabrication and testing could be found
in [13, 24, 25, 26].
VI. Contributions of FIB lithography
3D FIB strusturing
NanoMaker can be effectively used for 3D FIB patterning using special data
prepared by IonRevSim software which was developed in frame EC integrated
project CHARPAN (FP 6th) [28, 29].
S.V.Dubonos, B.N.Gaifullin, H.F.Raith, A.A.Svintsov, S.I.Zaitsev, Evaluation,
verification and error determination of proximity parameters (alpha,beta and
eta) in electron beam lithography, Microelectronic Engineering 21 (1993) 293-296
V.V. Aristov et al. A new approach to fabrication of nanostructures, Nanotechnology
6, 1995, p 35-39.
13.
A. Yu. Kasumov et al, Supercurrents through single-walled carbon nanotubes,
Science, v. 284 1999, pp 1508-1510
14.
S.V. Dubonos, H.F. Raith, A.A. Svintsov, S.I. Zaitsev, New Writing Routines
for SEM Based E-Beam Lithography, Microprocessing and Nanothechnology’99,
July 1999, Iokohama, Japan. (Award for the most impressive poster)
S.V.Babin, I.Kostitsh, A.A.Svintsov, Direct measurement of thermoeffect
influence of resist sensitivity in EBL. Microelectronic Engineering 17 (1992)
41-44
17.
S.V.Babin, and A.A.Svintsov, Effect of resist development process on the
determination of proximity function in electron lithography. Microelectronic
Engineering 17 (1992) 417-420
18.
S.V.Babin, I.Kostitsh, A.A.Svintsov, Model and measurement of resist heating
effect in EBL. SPIE Vol. 1671 (1992) 93-97
19.
A.A.Svintsov, S.I.Zaitsev, Simulation of heating in powerful electron lithography.
Microelectronic Engineering 27 (1995) 187-190
20.
A.A.Svintsov, and S.I.Zaitsev. Dose contribution of heating in electron
beam lithography J.Vac.Sci.Technol. B13(6),Nov/Dec 1995
21.
V. Aristov, M. Chukalina, A. Firsov, T. Ishikawa, S. Kikuta, Y. Kohmura,
A. Svintsov, S. Zaitsev, X-Ray Optics differential Contrast: design, optimization,
simulation, fabrication., XRM99, AIP Conference Proc. 507, 554-557, 2000
22.
A.A. Firsov, A.A. Svintsov, S.I. Zaitsev, A.Erko, V.V. Aristov, The first
synthetic X-ray hologram: results, Opt. Commun. 202(2002) 55-59
24.
A.K.Geim, S.V.Dubonos, I.V.Grigorieva, K.S.Novoselov, F.M.Peeters and V.A.Schweigert,
Non-quantized penetration of magnetic field in the vortex state of Superconductors,
Nature 407 (2000), p.55-57
25.
S.V.Dubonos, A.K.Geim, K.S.Novoselov and I.V.Grigorieva, Spontaneous magnetization
changes and nonlocal effects in mesoscopic ferromagnet-superconductor structures,
Phys.Rev.B 65 (2002) 2230513
26.
D.Y. Vodolazov, F.M. Peeters, S.V. Dubonos, and A.K. Geim, Multiple flux
jumps and irreversible behavior of thin Al superconducting rings, Phys. Rev.
B 67, (2003) 054506