Paper Title
Investigation of Abrasive Removal Depth and Surface Roughness of Sapphire Wafer using Different Polishing Pads for Chemical Mechanical Polishing with Different Abrasive Particle Sizes

Abstract
The study explores the effect of different abrasive particle sizes of slurry on the abrasive removal depth and surface roughness of sapphire wafer for chemical mechanical polishing using pattern-free polishing pad and hole-pattern polishing pad. Through experimental results of chemical mechanical polishing, with pattern-free polishing pad and holepattern polishing pad, regression equations for the average abrasive removal depths with abrasive particle sizes of slurry is obtained. From the experimental results and regression analysis, it is found that the increasing abrasive particle sizes of slurry, the average abrasive removal depth and is decreased and surface roughness is decreased. Besides, the surface roughness of using pattern-free polishing pad is smaller than that of using hole-pattern polishing pad with the same abrasive particle size of slurry. The abrasive removal depth of using pattern-free polishing pad is greater than that of using holepattern polishing pad with the same abrasive particle size. As seen from the current experimental results, when the abrasive particle size is smaller, under the same volumetric concentration of slurry there are more abrasive particles in the slurry, and hence a better abrasive removal amount will be achieved. Besides, when the abrasive particles of polishing slurry are smaller, under the same volumetric concentration of slurry, since there are more abrasive particles in the slurry, the scratches on the surface tend to be increased. Therefore, the surface roughness will be increased. Keywords -Chemical Mechanical Polishing, Sapphire Wafer, Abrasive Removal Depth, Surface Roughness, Abrasive Particle Size