Research For Aluminum Interconnected Line And Aluminum Plug Chemical Mechanical Polishing In ULSI

In the multilevel metalization techniques of the ULSI, the feature size is more and more smaller, so the wire become thinner and thinner., and the number of the interconnected layer become more and more .Aluminum will be used more and more popular as the first interlayer metal because of its high electronic conductor. Furthermore, the easier introduction of the process into existing factories, suits to fill in the contact and Via plug. For the IC character measure lower than 0.35μm,every interlayer metal must be global planarization. The Chemical mechanical Polishing (CMP) is the only global planarization techniques.. The aluminum CMP mechanism and slurry research is requisite.Aluminum slurries for the industry application are all acidity. It will erode the polishing equipment, bring metal ions, and cause environmental pollution. The alkaline slurry can decrease the erosion and have no metal ions. But the oxidant and the sedimentation issues baffle its appliance.In this paper, we first investigate the aluminum CMP mechanism, and analyze the alkaline slurry reaction dynamics. We advanced a mechanism model of AL CMP in the alkaline medium, which has the characters of strong chemical function, weak oxidation, easy dissolution with water, high removal rate, high selection lower destruction, high concentration, high planarization, small diameter and strong activity, with the H2O2 oxidant.. We selected alkaline slurry, which used silicon sol with diameter 15 nm to 20 nm as abrasives and hydrogen peroxide no metal ions as oxidant. We controlled removal rate by used organic alkali and it can avoid metal ion stain well. Through CMP experiment, we find the best oxidant. configuration whose concentration is lied between 2.5% and 3.0% and draw the conclusion that the aluminum removal rate reach the maximum when the PH value of slurry is between 10.8 and 11.2.In a word ,we design the new type slurries: steady small diameter silicon dioxide colloid slurry. The slurry have the advantages as no metal ions, no poison and no pollution, easier to clean, etc.