LAPPING WORK METHOD

PROBLEM TO BE SOLVED: To maintain work accuracy of a wafer, and decrease generation of an inferior part, by using an overheat means in the outside or inside to perform the heat insulation of a ruler table action surface during the time when a machine base is stopped, and starting the machine base in such a state when its operation is restarted. SOLUTION: Afer the last work batch on the operation last day before holiday is ended, a surface temperature of a lower surface plate 2 is about 30 deg.C. A surface of an upper/lower surface plate 1, 2 is washed and dried, an electric blanket 7 is laid between the surfaces, in an interposing condition thereof, the upper surface plate 1 is lowered down, to be left as in a condition carrying a current in the electric blanket 7, in the early morning after two days, a surface 2 of the lower surface plate is held at about 30 deg. temperature. In condition, immediately work is started in a prescribed work condition. From a first batch, TTV (change of thickness in a sheet of workpiece) value is about 0.5 micron, thereafter also continuously, a value of equal degree is obtained.