Experimental Investigation into Double-disc and Chemically Assisted Magnetorheological Finishing Process

Abstract

A new hybrid finishing process, namely, double-disc chemical-assisted magnetorheological finishing (DDCAMRF) process has been developed for the polishing of monocrystalline silicon wafers combining the benefits of the two processes namely, chemical–mechanical polishing (CMP) and magneto-rheological finishing (MRF). In the present work, the bonding between the Si atoms gets weakened by the chemical action which further softens the work surface while the rotation of MR fluid provides the desired mechanical force which assists in the removal of material from the work surface. An experimental setup for the hybrid finishing has been designed and fabricated for achieving the nanometric finishing of silicon substrates. Also, the process was further established by carrying out the experimental study which involves analyzing the influence of different process factors viz., polishing speed, % CIP concentration, slurry flow rate, and working gap, on the surface roughness (R_a) of a monocrystalline silicon wafer. An improvement of over 88.96% was observed in the surface roughness of a silicon wafer and a nearly mirror-like finish was observed while carrying out the polishing with the developed DDCAMRF process. The developed process resulted in enhancing the process performance ensuring better surface finish (i.e., with minimal defects) and reduced polishing time compared to different polishing techniques available.