Stability Of The Alkaline Slurry For GLSI Multilayer Copper Interconnection

New devices, new materials and new technology are driving the rapid development with the integrated circuit according to Moore’s law. Higher and higher of the integration level, smaller and smaller of the feature sizes and larger and larger of the wafer area are also put forward higher challenge of the precision machining technology. So chemical mechanical planarization(CMP) as the most widely used global planarization method has become a research hotspot. And slurry is the main consumable material in the cmp process, its performance is directly determined the planarization efficiency of the whole wafer.The alkaline slurry for copper interconnect polishing invented by hebei university of technology, microelectronics technology and material institute has a better performance and excluding BTA. The dishing, erosion and surface roughness value can be effectively controlled under the high polishing rate. The slurry is also not bad for the environment which has a very good industrialization prospect. However, the alkaline slurry also exist a common problem of all the slurries- poor stability. The stability of the alkaline slurry mainly consists of the following two aspects:(1) The first is the stability of the original slurry, the original slurry is that kind of slurry which is without dilution and H2O2 oxidizing agent. The concentration of each component is relatively higher.(2) The second is the stability of the using slurry. The using slurry refers to the slurry which is after dilution and adding the H2O2 oxidizing agent. Stability problem is not solved, slurry is unable to realize industrialization.Aiming at these problems, the main following research works have been done:(1) First of all, the instability mechanism of the original slurry was analyzed. Then the influence of the concentration of chelating agent, surfactant, silica abrasive and configuration process to the original slurry were studied, respectively.(2) Secondly, the instability mechanism of the using slurry was analyzed. Then the influence of the concentration of chelating agent and H2O2 oxidant to the using slurry were also studied through the orthogonal experiment.(3) Thirdly, Analyzed the mechanism of different kinds of H2O2 stabilizer, and the effect of different kinds of H2O2 stabilizing agent on the the using slurry were also studied.(4) Finally, Com4 pared the different kinds of chelating agent on the stability of the using slurry. Through those works, the stability of the original slurry and using slurry were prolonged on the basis of predecessors’ research. Original slurry is stable for more than six months, the using slurry for P1 is stable for more than 12 hours and the using slurry for P2 is stable for more than 24 hours. So this paper has an important guiding significance for the further research.