Effectiveness of a periodic annealing method to coarsen Cu grains in very narrow trenches

[Display omitted] •We proposed a new annealing method to coarsen Cu grains in very narrow trenches.•We identified the best annealing pattern using the phase field simulation method.•The best conditions achieved a 98% increase in the diameter of the Cu grains.•A preliminary experiment confirmed the effectiveness of the new annealing method. We developed a new annealing method, periodic annealing, to effectively coarsen Cu grains in very narrow trenches. In the periodic annealing method, the temperature of the specimen is elevated at a rapid rate to a target temperature and the temperature is oscillated at a certain periodicity. We identified the best oscillation conditions for the system temperature using the phase field simulation method. The best conditions achieved a 98% increase in the grain diameter of the Cu trench model. A preliminary experiment using an actual 70nm width wire showed about a 10% increase in the grain diameter, confirming the effectiveness of the periodic annealing method to coarsen Cu grains in very narrow trenches.