Preparation Of Nano-copper Thin Film And Basic Research Of Its Laser Shock Modifing

Based on the mechanism of laser shock process(LSP) increasing comprehensive mechanical property of metal's surface,in this paper,the experimental research was made on LSP of Cu films with nanometer scale, and the mechanical and electrical properties of Cu films after LSP were studied.Some mainly achievements made as followed.Cu films were prepared by D.C magnetron sputtering on the GCr15 and glass substrate individually.The purity of the copper target is above 99.99%.We changed the processing parameters such as sputtering power, sputtering pressure,substrate temperature and so on to get all kinds of Cu films.The surface topography and texture of Cu films were analyzed by the high-resolution scanning electron microscopic(SEM) and X-ray diffraction instrument.The relationship between sputtering parameters and mechanical and electrical properties was analyzed by nanoindentation and four point resistivity test system.The best processing parameters of preparing Cu films were obtained.When the substrate were not heated and the other sputtering parameters were not changed,the sputtering speed was increased first and then decreased with the increasing of sputtering power,and the texture was weakened first and then enhanced,and the electrical resistivity was also reduced first and then enlarged,but the grain size was gradually increased. The pivotal point appeared when the sputtering power was 200W in this experiment.When the sputtering power reached 24W,Cu films were amorphous.When the substrates were heated,the Cu films' quality was improved obviously.The surface of Cu films were smooth and the texture was homogeneous and dense,and the electrical resistivity was lower one order of magnitude than the room-temperature substrates',when the temperature of substrates were 150℃and 200℃.We changed the sputtering pressure,heating the substrates' to 150℃,keeping the sputtering power was 40W to prepare Cu films.We found that the films' quality was better when the sputtering pressure was 0.5Pa.The Cu films which were sputtered on GCr15 substrates were not good because that the substrates were not heated and the films had innerstress.Their grain size was smaller than that sputtered on glass substrates.Two LSP devices were chosen to shock process the Cu films on glass substrate.The results showed that nanosecond micro-shock device was fit for the Cu films which we made.When the LSP parameters were set as follows:pulse width was 5ns,spot diameter was 2mm,energy was about 80mJ,and every sample was shocked 10 times on the same place,the surface topography of Cu films were changed obviously through SEM photographs,mechanical and electrical properties were also improved.