Early Stages of Void Formation in Aluminum-Copper Lines Studied Using Positron Annihilation

We have applied positron annihilation spectroscopy to examine the formation of voids in SiO sub 2 -passivated 1 mu m x 1 mu m Al-0.5 wt.% Cu lines. Samples were heat-treated both ex situ and in the positron beam to monitor void formation as a function of time and temperature. By measuring the fracti...

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Bibliographic Details
Published in:Applied physics letters 1994-07, Vol.65 (1), p.52-54
Main Authors: Simpson, P J, Umlor, M T, Lynn, K G, Rodbell, K P
Format: Article
Language:English
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Summary:We have applied positron annihilation spectroscopy to examine the formation of voids in SiO sub 2 -passivated 1 mu m x 1 mu m Al-0.5 wt.% Cu lines. Samples were heat-treated both ex situ and in the positron beam to monitor void formation as a function of time and temperature. By measuring the fraction of 3- gamma annihilations (a sensitive indicator of large open volume defects) we have established that voids are present at the interface between the aluminum alloy lines and the SiO sub 2 passivation before heat treatment. The 3- gamma fraction then grows to a maximum in < 1 h at a temperature of 300 deg C. Changes in the Doppler-broadening S parameter are also observed. Studies are underway to apply the same methodology to investigate electromigration.
ISSN:0003-6951