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Impact of the Unique Physical Properties of Copper in Silicon on Characterization of Copper Diffusion Barriers
Author(s) -
Istratov A.A.,
Flink C.,
Weber E.R.
Publication year - 2000
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200011)222:1<261::aid-pssb261>3.0.co;2-5
Subject(s) - copper , materials science , silicon , auger electron spectroscopy , penetration (warfare) , secondary ion mass spectrometry , spreading resistance profiling , annealing (glass) , diffusion barrier , metallurgy , analytical chemistry (journal) , ion , chemistry , nanotechnology , environmental chemistry , physics , organic chemistry , layer (electronics) , operations research , nuclear physics , engineering
In this paper, we establish a connection between the physical properties of copper in silicon substrates and the problems of characterization of copper diffusion barriers for ultra‐large scale integration (ULSI) technology. We show that many of the methods successfully used for detection of the failure of aluminum diffusion barriers are poorly suited for characterization of barriers for copper metallization technology. This is because the unique physical properties of copper make its diffusion and precipitation behavior in silicon significantly different from those of other metals. These properties must be taken into account in studies of the detrimental effect of copper on device yield and in development of thin diffusion barriers for copper metallization. The sensitivity of most depth profiling techniques (such as secondary ion mass spectrometry, Auger electron spectroscopy, or Rutherford backscattering) is not sufficient to detect barrier failure before the dissolved copper concentration in the bulk reaches its solubility limit at the back‐end processing temperature (e.g., 2 × 10 13 cm —3 at 450 °C). The electrical measurement techniques, such as analysis of I – V characteristics of p–n junctions formed by ion implantation under the barrier layers are more sensitive to penetration of copper than depth profiling techniques, but cannot determine the copper contamination level quantitatively. Emerging tools suitable for detection of copper penetration at technologically relevant levels are discussed.