Method for controlling thickness of wafer-like work pieces under lapping and a lapping machine therefor

摘要

The present invention relates to an improvement in the lapping method of wafer-like work pieces in a lapping machine to lap the work pieces by sandwiching them between relatively rotatable upper and lower surface plates, in which the thickness of the work pieces under lapping is determined by an in-machine manner with a sensor mounted on the upper surface plate. Different from conventional lapping methods with an in-machine measurement of the thickness, the thickness of the work pieces is computed only once at regular intervals corresponding to one relative revolution of the surface plates so that the errors due to the operation per se of the lapping machine such as the undulated revolution of the surface plates, vibration of the machine and the like can be eliminated and very much improved control means for the thickness of the work pieces under lapping can be obtained.