Research On The Experiments Of Copper Thin Films Onto Silicon Wafers Tread By Laser Shock Processing

Methods used to strengthen generally cause a pronounced decrease in electrical conductivity,so that a tradeoff must be made between conductivity and mechanical strength.In order to improve effectively electrical conductivity and mechanical properties of copper interconnects in the integrated circuit,this paper analyzed the influence of Cu films quality deposited on Si substrate on the DC magnetron sputtering processing parameters.High quality nano-copper films were prepared by optimizing sputtering processing parameters.The experimental research was made about nano-copper films being laser shock processing(LSP) on this basis.Some achievements were made as following.The deposition rate increased with the increase of sputtering power liner relationship.Deposition rate increased with the increase of sputtering pressure in the sputtering pressure to 0.3～0.5Pa,at the same time the film deposition rate reached maximum;Deposition rate decreased rapidly with the increase of sputtering pressure later.The surface roughness of Cu films appeared small value in sputtering power 60W～100W.While the surface roughness of Cu films appeared larger value with the increase of sputtering power laser.The Cu films were prepared when pressure was 0.5Pa and substrate temperature was 150℃. Because the substrate thermal effect and films particles diffusion increased and the islands between the islands connected and hollow is filled,The films surface become smooth and dense due to substrate thermal effects and films particles diffusion increased and the islands between the islands connected and hollow were filled.The intensity of (111) diffraction peak intensity was growing with the increase of sputtering power.It indicated that the increase of sputtering power made exaltation of film crystallinity.The hardness and elastic modulus of Cu films with the increase of sputtering power first increased and then decreased.Substrate temperature can inhibit the columnar mode and grain growth process.The XRD results show that grain preferred orientation (111) plane and(100) plane with increase of the temperature.The hardness and elastic modulus of Cu films increased with the increase of substrate temperature(＜150℃).The maximum of hardness and elastic modulus is 5.0GPa and 156.4GPa respectively when the temperature was 150℃.But the hardness and elastic modulus decreased with the temperature continues to rise to 300℃.The hardness and elastic modulus of Cu film was stable when the sputtering pressure was 0.5Pa.The resistivity of Cu films decreased with increase of sputtering power.As the substrate temperature "structure zone model" effect,the Cu film resistivity decreases when the substrate temperature was less than 150℃. The resistivities(ρ) begin to increase gradually at various temperatures ranging from 150℃to 300℃,but the rate of increase is not significant. The resistivity abnormal increased when the substrate temperature was 400℃.The resistivity of Cu films increased with argon pressure increased in the range of 0.15～2Pa.Laser Shock Processing was optimized to shock process the Cu film which deposited on Si substrate.Great changes occurred in the film after LSP.The results show that plastic deformation occurred in the film surface and the organizational structure became more compact and surface roughness reduced significantly.Nano-indentation test results show that the hardness and elastic modulus increased by the largest up to 106.58%and 138.82%,respectively.Four-probe test results show that the electrical properties of Cu films has been improved in the forming of varying degree and the highest resistivity decreased to 25.8%.