Investigation on the Chemical Mechanical Polish of Metal Os

Osmium (Os) may be used as new barrier material in copper interconnects of ultra-large scale integration. In this work, chemical mechanical polish experiments were done on Os disk using home-made slurry, the effect of pH value, down force, chelating agents, inhibitor species, the concentration of the inhibitor, H2O2 concentration and SiO2 concentration on material removal rate (MRR) was investigated. The results reveal that MRR is 13.1 nm/min when the slurry contains 1wt.% H2O2, 1wt.% SiO2, 1 wt.% citric acid, 1mM BTA and pH =9 and the down force was 1 psi. The influence of the BTA concentration on the corrosion on the surface of Os was analyzed using electrochemical analysis method; it was found that the maximum value of Ecorr appeared when the BTA concentration was 1.5 mm