Investigation of the deposition mechanism of Cu seed layer atoms on the Ta (001) surface from the atomic perspective

Abstract

Ta barrier layers are commonly used in microelectronic devices to prevent direct Cu-Si contact. To better understand the deposition mechanism of Cu seed layers on Ta barriers, which is crucial for improving film quality, we conducted molecular dynamics simulations to analyze this process at the atomic level. The investigation focused on analyzing the effects of deposition temperature and incident energy on film surface roughness, interface mixing and dislocation defects, systematically elucidated the underlying mechanisms. Simulation results indicate that only a minor amount of interface mixing occurs when the deposition energy approaches 40 eV, confirming the effectiveness as a barrier material. At lower deposition energies, increasing the energy significantly reduces the surface roughness of the Cu seed layer, but beyond 5 eV, it stabilizes around 0.9 Å. Dislocation density continuously decreases substantially with increasing energy. The deposition temperature is positively correlated with the surface roughness, while dislocation defects fluctuate with temperature, peaking near 400 K and reaching minimal values near 600 K. With further increases in temperature, the dislocation density begins to rise slowly. Consequently, this work conducted a comprehensive analysis of the deposition mechanism, which has significant implications for practical deposition processes of Cu seed layers in semiconductor devices, offering novel insights for the microscopic analysis of deposition parameters applicable to thin film deposition in other contexts.