Influence of electrodeposition parameters on the characteristics of NiMoP film

In the present work, NiMoP thin films have been electrodeposited from citrate bath onto Cu sheets for the application as diffusion barriers and metal capping layers in the copper interconnect technology. The study focused on the effect of the electrodeposition parameters including [MoO42 −]/Ni2 + molar ratio, temperature, pH and current density on the properties of NiMoP films. The morphology, textural components, and phase structures of the coatings were evaluated using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and X-ray diffraction (XRD), respectively. The results revealed that the maximum deposition rate was found at 0.122 [MoO42 −]/Ni2 + molar ratio. However, for the highest examined [MoO42 −]/Ni2 + molar ratio, a considerable decrease in the rate of the process is subsequently observed. The influences of deposition current density, solution pH and deposition temperature at a certain [MoO42 −]/Ni2 + molar ratio on the plating rate and chemical composition were studied. NiMoP alloys of high Mo at.% as-deposited films showed an irregular microcrack structure while those of low Mo at.% showed an amorphous/nanocrystalline structure. However, after heat treatment at 400 °C for 1 h, the deposited films converted into polycrystalline structure. The magnetic nature of coated materials has been studied by hysteresis loop measurements. The corrosion results were calculated from polarization Tafel lines and electrochemical impedance spectroscopy (EIS) for as-plated NiMoP coatings in a 3.5% NaCl solution.