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Quantitative electron spectroscopic imaging studies of microelectronic metallization layers
Author(s) -
J. Marien,
Jürgen M. Plitzko,
Ralph Spolenak,
R. Keller,
Joachim Mayer
Publication year - 1999
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.1999.00476.x
Subject(s) - microelectronics , materials science , focused ion beam , crystallite , tin , ion , analytical chemistry (journal) , optoelectronics , chemistry , metallurgy , organic chemistry , chromatography
The combination of focused ion beam (FIB) sample preparation and quantitative electron spectroscopic imaging is an ideal tool for the investigation of layered structures used in microelectronic metallization schemes. In the present work, Si 3 N 4 /Cu/Si 3 N 4 /SiO 2 /Si and Al/TiN/Ti/SiO 2 /Si metallization layers produced by physical vapour deposition are investigated. We apply series of energy filtered images in the low loss region for a mapping of the sample thickness which makes it possible to refine the parameters of the FIB process. We also show how series of energy filtered images in the core loss region can be used to obtain elemental distribution images and chemical bonding information on these samples on a nanometre scale. For materials with a small grain size and/or a strong variation in Bragg orientation, the intensity distribution of the elemental map is strongly influenced by the superimposed Bragg contrast. This detrimental effect can be reduced greatly by using hollow cone illumination, as is demonstrated for polycrystalline Cu. One striking feature observed in Cu layers prepared with FIB is strong, regularly arranged contrast variations caused by subsurface defects in the Cu grains. We suppose that these defects are a consequence of a strong interaction of Ga atoms from the FIB with Cu.