| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 89 === This dissertation aims to study the removal rate of the copper Chemical mechanical Polishing (CMP) from the viewpoint of chemical reaction in chief. The establishment of the CMP model is divided into the mechanical part、physical part and the chemical part. In mechanical part, the contact models among wafer and abrasive and polish pad are considered, they include the elastic deformation arising at asperities and substrate of polishing pad and the elastic-plastic deformation at the interface between wafer and abrasive during CMP. We also estimate the real contact pressure and the ratio of solid contact area of abrasive and asperity of pad at the same time. We develop the Reynolds equation considered the effect of micro-particle and surface roughness in the analysis of flow field between wafer and pad. We also estimate the distributions of the hydrodynamic pressure and the velocity of the fluid field by numerical analysis. In physical part, we considered the effect of abrasive aggregation of the slurry in the result of polishing to estimate the real contact pressure between wafer and aggregated abrasives with the real contact area. In the study of the chemical part, the rate constant of chemical reaction that is changed by the mechanical stresses from the viewpoint of tribochemistry is concerned. The concentration mass transfer equation was applied in the analysis of the reactant’s concentration of slurry during the CMP by numerical analysis.
In this study we considered the effect of the abrasive aggregation of the slurry in（1）the analysis of flow field between wafer and pad；（2）the contact situation between wafer and abrasives；（3）the surface roughness and contours after polishing. With the assumption of chemical reaction equivalent to the removal rate of copper CMP, we can examine the correct of theoretical model by the removal rate and surface roughness parameters from CMP experiment and wafer surface contour experiment.
Several parameters that were considered in this model include the attack angle of the wafer and the limiting strength of the copper in the slurry. They must be given in the theoretical analysis. The theoretical results obtained from the changes of these parameters are compared with the experimental removal rates. After we determined these parameters, the removal rate obtained from the theoretical analysis with the value of average secondary particle size estimated by the theory of abrasive aggregation can be compared with the results of experiment to prove the accuracy of this model. With the theoretical analysis before polishing, we can thus forecast the removal rate and non-uniformity after CMP.
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