Study Of Barrier Laver Technology Of Semicondutor Wiring Of Cu

With the continuous scaling down of the semiconductor feature size,the effective current carrying capacity of the interconnection increases sharply and the electromigration phenomenon becomes more and more obvious,which greatly affects the stability of the interconnection system.The traditional A1 interconnection has been difficult to meet the requirements of the integrated circuit Rapid development of the requirements,Cu Metal with the advantages of low resistivity,anti-electromigration ability gradually replace the Al,become the most widely used interconnect metal.However,Cu diffuses rapidly in Si and its oxides.Once it enters the Si device,it will become a deep level acceptor impurity and form a high-resistance compound,which causes the leakage current of the circuit system to increase and degradation or even failure of the performance of the device.Cu also has poor adhesion with silicon dioxide,silicon,and is easy to be oxidized in the air,resulting in increased resistivity of interconnection line.Therefore,it is necessary to add a layer between the Cu metal and the semiconductor substrate,which can effectively prevent the mutual diffusion.It is an important direction for the rapid development of integrated circuits and the main research contents of the research to design a diffusion barrier with low resistivity,high reliability and excellent performance,and use the structure with barrier layer/copper film as the interconnection system.In this paper,we use TiN-based composite film as the diffusion barrier,supplemented by Ti single metal layer as a transition layer,increasing the adhesion between the layers of the interconnection system,and reducing the contact resistance.We use Cu,Si as the interconnection metal and semiconductor substrates,magnetron sputtering as the main process.We study the influence of the Structure,sputtering process and annealing condition on the barrier properties.In addition,We studied the failure mechanism of the TiN barrier layer.Acomplete Cu-based semiconductor metallization system is prepared and the direct contact between the interconnection layer and the substrate Si is studied.Reliable experimental data were provided for the practical application of the Cu interconnect process.The main work and achievements are as follows:1,We analysised the diffusion and failure mechanism of copper interconnection system,designed and parpared the barrier layer with composite structure of Ti(15 nm)/TiN(15 nm)/Ti(15 nm).The experimental results showed that the this failure temperature of composite barrier Layer can be up to 900?.We also studied the effects of N2 flow rate on the deposition rate,film composition and grain orientation of TiN films prepared by magnetron sputtering by experiments.2,Based on the through understanding of magnetron sputtering technology,we fabricated the complete copper interconnection system with the structure of TiN/Cu/Ti/TiN/Ti/Si and analyzed the characteristics of the interconnection system with XRD,four probe.The copper interconnection system can be finished in one time in the same vacuum period,which has good operability and industrial application value.3,The TiN(20 nm)/Ti(15 nm)thin film samples were prepared on n-type and p-type silicon,respectively.Combining the annealing process,the effects of annealing on the contact of Ti with n,p-type Si were studied.And we also measure the the block resistance of the barrier and interconnect system.Experimental results indicate that an ohmic contact is formed when Ti is attached to n-type Si and p-type Si.