To investigate the change of the mechanical properties of soft metals doped PVD (Physical Vapor Deposition) coatings after the migration of soft metal to the surface, TiN-Cu coating was deposited on Si (100) by magnetron sputtering. The microstructure and mechanical properties at room temperature and after vacuum heat treatment at 300 °C were investigated. The results showed that the grains were clustered and the microstructure was porous for TiN-Cu coating at room temperature, while many micro- and nano- sized Cu particles were observed on the surface after vacuum heat treatment at 300 °C. The elastic properties of the TiN-Cu coating after vacuum heat treatment at 300 °C degraded compared with that at room temperature. The hardness and elasticity modulus of TiN-Cu coating kept constant (3.7 GPa and 125.0 GPa, respectively) with the increase of nano-indentation depth, while the hardness and elasticity modulus of TiN-Cu coating after vacuum heat treatment at 300 °C increased gradually. Keywords: TiN-Cu coating, Vacuum heat treatment, Mechanical properties, Nano-indentation depth