Effect of FAP characteristics on fixed abrasive polishing of CaF2 crystal

Pad is an important factor, which bears pressure to mechanically remove material in chemical mechanical polishing process. Owing to the abrasives fixed in pad, fixed abrasive pad (FAP) becomes more important and influences material removal and surface quality of wafer. The characteristics of FAP, abrasive type, particle size and matrix hardness, were analysed and the effect on material removal rate (MRR) and surface quality was investigated in fixed abrasive polishing of CaF2 crystal. The results indicated that FAP with 3-5 μm diamond abrasive and soft matrix is suited to polish CaF2 crystal. And the better surface quality with surface roughness Sa 7.27 nm and material removal rate 192 nm/min, can be achieved in fixed abrasive polishing of CaF2 crystal.