Research On Alkali CMP Slurry For Precise Polishing Of Copper Interconnect Of GLSI With Low Abrasive Concentration

With the continuous development of integrated circuit technology,multilayer copper wiring has replaced aluminum as the main mode of integrated circuit wiring.Copper has a lower resistivity than aluminum,and it is difficult to transfer electrons.But when the copper is electroplated,the surface of the wafer will form uneven shape.The wafer is rough polishing and precise polishing by CMP,and a large amount of copper is removed from the surface by rough polishing.The remaining copper is removed by precise polishing,and the barrier layer is retained.In this paper,the stability,removal rate and nouniformity of the wafer were studied in three aspects.Comparative analysis of the alkaline slurry FA/O II chelating agent system and glycine complexing agent system In each system,the effects of various factors on the stability,removal rate and surface roughness of the polishing slurry were determined by single factor experiments,and the influence of AEO-15 was mainly studied.The antioxidant effect of complexing agent,complexing agent in the slurry,can coexist with the oxidant,so as to realize the stability of alkaline slurry The slurry FA/O II chelating agent system has high removal rate,good passivating effects,the wafer surface roughness is reduced to 2.03nm;glycine complexing agent system of alkaline slurry in silica sol concentration 1wt%,AEO-15 3wt%,glycine content 0.5wt%,film agent is 100 ppm under the condition of stability 4 days.A weak alkaline polishing solution was proposed to solve the extension of the dishing in planarization,and the copper in the concave was effectively protected under the coordination of oxidation and passivation.An oxide film is formed on the surface of the wafer,A passive film is formed at the same time.According to the mutual influence of the two synergistic,select the optimal ratio in the glycine system for planarization experiments,the dishing is 945?,it has been corrected.The system provides a theoretical basis for chemical mechanical planarization,and provides important reference value for the study of weakly alkaline copper CMP in the future.