Application of the Avrami rate equation to electromigration damage in Al–1%Si interconnections

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Abstract
Al–1%Si test stripes were subjected to life testing, and the resistance-versus-time behavior of individual conductors were collected for subsequent analysis. The failure times were log-normally distributed and the median time to failure decreased with increasing temperature. Analysis of the resistance-versus-time data was performed using the Avrami rate expression, R(t)=R0 exp[(Bt)n] proposed earlier by Rodbell, Rodriguez, and Ficalora [J. Appl. Phys. 61, 2844 (1987)]. It is found that values of the parameter n vary for identical conductors stressed under the same conditions. Thus the physical significance of this parameter with respect to identifying mechanisms of the rate-determining step is questionable. On the other hand, dramatic changes in the value of this parameter are observed over the temperature range of this study; this reflects changes in the growth geometry. It is suggested that such effects can be used to establish appropriate stressing conditions during life testing to avoid possible complications in the interpretation of the reliability data.