Influence of Additive on Micro-structure and Nano-indentation Properties of Nanocrystalline Cu Films

The nanocrystalline Cu films of different grain sizes were prepared by brush plating.Transmission electron microscopy(TEM) was used to analyze the micro-structure of the nanocrystalline Cu films and calculate their grain size range.Room-temperature nano-indentation experiment was performed on the nanocrystalline Cu films by universal nano/micro material tester UNMT-1.The results show that additive has a great influence on the grain size and indentation hardness of the nanocrystalline Cu films.When the content of the additive is 45 g/L,the minimum average grain size of the films is about 32 nm and the indentation hardness 3.26 GPa,but when the content of the additive is 1 g/L,the grain size increases to around 150 nm and the indentation hardness decreases to 1.72 GPa.