63rd Annual Gaseous Electronics Conference and 7th International Conference on Reactive Plasmas
Volume 55, Number 7
Monday–Friday, October 4–8, 2010;
Paris, France
Session FT: Special Evening Session
8:00 PM–10:00 PM,
Tuesday, October 5, 2010
Room: 151
Chair: Makoto Sekine, Nagoya University
Abstract ID: BAPS.2010.GEC.FT.1
Abstract: FT.00001 : Plasma Processing for Nanoelectronics --- History and Prospects*
8:00 PM–8:35 PM
Preview Abstract
Abstract
Author:
Michael Lieberman
(UC Berkeley)
Plasma processing is a crucial technology for fabricating
trillions of nanometer-size transistors on a silicon wafer [1].
It evolved from humble beginnings in the early 1900's: the
silver-coating of mirrors by physical sputtering in dc glow
discharges. The late 1950's - early 1960's saw extensive studies
of physical and reactive sputtering in capacitive rf reactors.
Isotropic plasma etching, mainly for photoresist stripping, was
developed in the late 1960's - early 1970's, and etching of many
other important materials was demonstrated. Three key advances in
the late 1970's made plasma processing technology indispensable:
(a) the discovery of ion-enhanced (anisotropic) etching [2]; (b)
the development of SiO$_2$ etching with high SiO$_2$/Si selectivity
[3]; and (c) the controlled etching of passivating films, eg,
Al$_2$O$_3$ over Al [4]. As scale-down to current 32 nm (100
atom) transistor gate lengths proceeded, etching discharges
evolved from a first generation of ``low density'' reactors
capacitively driven by a single source, to a second generation of
``high density'' reactors (inductive and electron cyclotron
resonance) having two power sources, in order to control
independently the ion flux and ion bombarding energy to the
substrate. A third generation of ``moderate density'' reactors,
driven capacitively by multiple frequency sources, is now used to
further control processing characteristics, such as ion energy
distributions, uniformity, and selectivity. There
is yet much to be understood, e.g., the physics of
multiple-frequency sheaths, nonlinear frequency interactions, and
electromagnetic effects such as standing waves. Beyond the 6--11
nm transistor limit lies a decade of further improvements for
conventional nanoelectronics, and beyond that, a dimly-seen
future of spintronics, single-electron transistors, cross-bar
latches, and molecular electronics.
\\[4pt]
[1] H. Abe, M. Yoneda and N. Fujiwara, ``Developments of Plasma
Etching Technology for Fabricating Semiconductor Devices,'' Jpn.
J. Appl. Phys. 47, 1435 (2008).
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[2] N. Hosokawa, R. Matsuzaki and T. Asamaki, ``RF Sputter-Etching
by Fluoro-Chloro-Hydrocarbon Gases,'' Jpn. J. Appl. Phys. Suppl.
2, Pt. 1, 435 (1974).
\\[0pt]
[3] R.A.H. Heinecke, ``Control of Relative Etch Rates of SiO2 and
Si in Plasma Etching,'' Solid State Electronics 18, 1146 (1975).
\\[0pt]
[4] S.I.J. Ingrey, H.J. Nentwich, and R.G. Poulsen, ``Gaseous
Plasma Etching of Al and Al2O3,'' USP 4,030,967 (filed 1976).
*Supported by UC Discovery Grant ele07-10283 under the IMPACT program and the Department of Energy Office of Fusion Energy Science Contract DE-SC0001939; special thanks to J.W. Coburn
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.GEC.FT.1