Manufacturing: Surface Finishing

Polishing -

A chemical-mechanical-polishing CMP process, where a sample is smoothed or burnished to a glossy, finished surface using cerium oxide powder mixed with water or colloidal silica. Polished surfaces are denser, harder, and have more intrinsic stresses than lapped surfaces. Polishing creates more friction, more drag, and higher substrate/sample temperatures than lapping processes. Polishing to a glossy surface usually starts around the outside edges of a specimen/sample and works its way inward over time.

Either of two possible common schools-of-thought may be used to determine how much material you should seek to remove during polishing:

1. Remove a depth of material on your specimen/sample equal to at least one-half the abrasive-slurry grit-particle size (e.g. if 12 µm calcined alumina powder was used during lapping, remove at least 6 µm of material during polishing).
2. Remove a depth of material on your specimen/sample equal to at least three times the abrasive-slurry grit-particle size (e.g. if 9 µm calcined alumina powder was used during lapping, remove at least 27 µm of material during polishing). This depth of polishing is especially used to remove all material that may be within cracked valleys or cracked grooves caused by the abrasive slurry grit particles.