Nucleation and growth of low resistivity copper thin films on polyimide substrates by low-temperature atomic layer deposition

•A multi-pulse process of Cu precursor for low-temperature ALD using Cu(hfac)2 and Et2Zn is developed.•A conformal and continuous copper seed layer with low-resistivity (5.6 μΩ·cm) is deposited on treated PI via ALD.•The adsorption of Cu(hfac)2 on the surface of PI is analyzed by XPS.•The microstructures and elemental composition across the Cu/treated PI interface is investigated by TEM equipped with EDX capabilities.•The nucleation and growth model of ALD-Cu thin films on polyimide substrates by low-temperature ALD is proposed.