Study on fundamental polishing characteristics in chemical mechanical polishing of gallium arsenide (GaAs) wafer

Chemical mechanical polishing (CMP) experiments were carried out to evaluate the effect of the process parameters on the polishing characteristics of GaAs wafers. CMP of the GaAs wafers was conducted on a commercial polisher; the polishing slurry was freshly prepared from analytical grade materials prior to each experiment. The experimental results indicated that (1) the surface roughness Ra decreases on increasing the rotational speed of the polishing pad and polisher head, and polishing load; (2) the polishing load is one of the main factors that affect the total thickness variation (TTV). With the increase in the polishing load, the TTV of the wafer was reduced accordingly; (3) the material removal rate (MRR) increases on increasing of the rotational speed of the polishing pad, the rotational speed of polisher head, and the polishing load; the change of polishing load has the most obvious effect on the MRR.