Controllable large scaled nanotwin formation in Cu film at lower temperatures

By means of low temperature rapid annealing, it is found that an abrupt thermal stress relaxation occurs in Cu film at the beginning of cooling, which greatly increases the driving force for twin nucleation and growth. Consequently, high-density nanotwins (nt) are successfully produced in as-plated Cu film at wafer-level under temperatures as low as 300 °C, which is much lower than conventional processes (above 550 °C), making it fully compatible with the semiconductor industry. This enhanced annealing processing provides not only a cost-effective approach for large scaled void-free nt-Cu synthesis together with half-quantitatively controllable twin spacing, but demonstrates the prospect and significance of inconspicuous annealed nanotwins on the application of microelectronics.