The Defects Of Barrier Layer Planarization With Alkaline Slurry In GLSI Copper Interconnection

With the rapid development of integrated circuit industry,the small scale integrated circuit gradually developed into gigantic scale integrated circuit,GLSI.At present,internationally the feature size of gigantic scale integrated circuit(GLSI)is 28nm/22 nm which has been achieved large-scale production,the layer of multilayer metal interconnection up to more than 10 layers.In order to ensure the various parameters and device performance of final wafer to meet customer requirements,it requests to get better flatness of the wafer surface after each layer wiring.Chemical mechanical planarization(CMP)is recognized as a unique global planarization technology so far.While the manufacturing chemical mechanical processes required in integrated circuit planarization,barrier CMP is a key which ultimately decides the effect of the wafer CMP,and directly impacts the device performance and yield reduction.Due to barrier CMP involves a variety of different materials,the process is complex,and after polishing appears dishing,erosion and abnormal electrical parameters easily,which are the challenges of the barrier CMP,so the further research on the barrier CMP process has very important practical significance.In this paper,the effect of slurry components on removal rate of copper and tantalum,mechanism of chelating FA/O II on copper disk and galvanic corrosion problem between copper and tantalum are explored through single factor experiments and copper,tantalum electrochemical experiments.Then the novel alkaline barrier layer slurry is applied to the planarization experiment of 12 inch copper,TEOS blankets and 65 nm technology node copper pattern wafer,and detect surface defects of wafer polished,to research the effect of FA/O II chelating agent on removal rate of copper and dielectric,rate ratio,dishing,surface roughness and resistance,the effect of different slurry ratio on copper and dielectric removal rate consistency.At last,the slurry of best ratio is applied to copper pattern wafer and detect the correction of dishing/erosion after barrier polishing.The results indicate that the removal rate of Cu and TEOS increase with the increasing of FA/O II concentration,which improve the dishing correction ability;when the slurry consists of 0.7 ml/L FA/O II,60ml/L surfactant and 500ml/L colloid silica,copper blanket gets a lowest surface roughness,2.34 nm;when the volume fraction of FA/O II and surfactant is 0.7 ml/L and 60 ml/L,alkaline barrier slurry gets a better rate selection ratio and better consistency of removal rate,the consistency of copper and dielectric removal rate is 4.33% and 4.76%,respectly;the dishing of pattern is under 520 ?,and errosion is below 306 ?,which meet the requirements of industrial production.