| This paper concerns the kinetics of the self-annealing mechanism in electroplated Cu thin films. The annealing kinetics of electroplated Cu thin films is characterized by monitoring the change in the sheet resistance and X-ray diffraction intensity with the variation of film thickness and temperature. The kinetic parameters of annealing, the time exponent and the activation energy, are determined by fitting the results to the KJMA (Kolmogorov, Johnson, Mehl and Avrami) model. It is found that the film thickness has little influence on the activation energy but does change the time exponent. From subsequent analysis of the final grain structure using transmission electron microscopy, it is then concluded that the self-annealing occurs mainly by the process of the recrystallization and that annealing kinetics dependence on film thickness stems from the hindering of grain boundary migration at the Cu/substrate interface. In case the film thickness is smaller than the nuclei size or when there is not enough stored energy in the film to drive nucleation and grain growth, the self-annealing may occur by recovery. |
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