Abstract: The mechanism of CMP material removal is investigated.Katsuki has proposed wear behavior between a single slurry particle and the wafer surface based on atomic force microscopy (AFM) measurements.The scratch depth under real CMP conduction is on the order of 1e-11m,as determined from the linear regression mechanism.A spectroscopic ellipsometry (SE) tool was used to study the relationship between the thickness of the oxidized layer and the chemical action time,which was presented by Nishizawa.Since the real CMP chemical action time is on the order of 1.0e-8s,the thickness of the oxidized layer is on the order of 1e-13m,as evaluated by the theoretical model based on the experiment.A closed-form equation supported by previously published experimental data is also derived from the material removal rate in terms of the molecular mechanism.The experimental results,in combination with the calculations,indicate that the CMP material is removed at the molecular scale.These analyses are useful to substantiate the molecular-scale mechanism of CMP material removal in addition to its underlying theoretical foundation.

Key words: chemical mechanical polishing, molecular-scale mechanism experiment, theoretical model