Polishing amount control system and method for same

Abstract

A polishing amount control system and method for same which can quickly feed back the results of measurement of a coating layer of a workpiece to the next polishing work so as to improve the productivity of the workpieces and further enable high precision polishing work. The thicknesses of the plating layers of the two surfaces of a magnetic disk W polished by a double-side polishing apparatus 1 are measured by an X-ray thickness meter 2. The rotational speeds of the drive motors 15 and 18 of the double-side polishing apparatus 1 are controlled in accordance with the results of the measurement. Specifically, the polishing amounts of the plating layers of the upper surface and lower surface of the magnetic disk W polished next become within 1.8 .mu.m to 2.2 .mu.m by controlling the rotational speeds of the upper platen 13 and the lower platen 11. The thickness difference of the upper and lower surfaces of the same magnetic disk W become within -0.15 .mu.m to +0.15 .mu.m by controlling the rotational speed of one of the upper platen 13 and lower platen 11.