Development of a polishing disc containing granulated fine abrasives

Polishing technology has provided the possibility of obtaining super smooth surfaces on semiconductor and other brittle materials for electronic and optical applications. In this study, a new manufacturing method for a polishing disc with fixed fine abrasive grains is proposed. This manufacturing method consists of three main processes. In the first process, an undiluted solution of abrasives is produced by adding some sodium alginate into the solution in which fine abrasive grains of SiO₂, Al₂O₃ and Cr₂O₃ are dispersed. Next, by dropping the undiluted abrasive solution into a lactic acid calcium solution, the fine abrasive grains are granulated into spheres having diameters of 2-3 mm. In the second process, the granulated spheres are combined using the same undiluted abrasive solution as a binder. In the last process, the combined body of granulation spheres is dried up and formed by a lathe. The polishing disc produced by this method has a bulk density of 0.5 g/cm³, a Vickers hardness less than HV10. Observations using a scanning electron microscope show that the polishing disc has a high-density and homogeneous structure and the bonding strength is low. Experimental results indicate that the developed polishing disc can be used in high efficiency polishing for silicon wafers.