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Ion-Enhanced Dry Etching of Magnetic Multilayers: Post-Etch Cleaning and Effects of UV Illumination

Published online by Cambridge University Press:  10 February 2011

H. Cho ,
K. P. Lee ,
K. B. Jung ,
F. Sharifi ,
J. Marburger  and
S. J. Pearton
H. Cho
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville FL 32611
K. P. Lee
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville FL 32611
K. B. Jung
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville FL 32611
F. Sharifi
Affiliation:
Department of Physics, University of Florida, Gainesville FL 32611
J. Marburger
Affiliation:
Department of Physics, University of Florida, Gainesville FL 32611
S. J. Pearton
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville FL 32611
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Abstract

Patterning of magnetic multilayer structures of the type used for MRAMs (e.g. NiFeCo/CoFe/Cu/CoFe/NiFeCo) is generally performed with ion milling, but this can degrade the coercivity of small (micron-size) MRAM elements and lead to sidewall redeposition. In high ion density reactive plasmas (Cl2/Ar) it is possible to produce ion-enhanced desorption of otherwise involatile halogenated reaction products, and achieve practical etch rates (∼600 Å/min) for the multilayers. However, removal of the chlorinated etch products from the feature sidewalls is critically important to avoid corrosion. We have used de-ionized water rinsing or in-situ exposure to H2, O2 or SF6 plasmas for removal of these etch residues. Some slight degradation in magnetization was observed in O2 plasma treated structures, but the other cleaning procedures produced no change in magnetic properties and excellent long-term stability. UV illumination of the sample surface during etching is also found to enhance etch rates, as has been reported previously for room temperature etching of Cu.[1]

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 585: Symposium L – Fundamental Mechanisms of Low-Energy-Beam Modified Surface , 1999 , 123
Copyright
Copyright © Materials Research Society 2000

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