An in-process measurement probe for profile generation with using no datum

This paper presents newly developed force controllable measurement probes which will be used for profile generation with using no external reference. These probes are able to perform measurement and fabrication simultaneously. Measurement ability of probe type 1, which has cantilever and lapping pad, is tested experimentally. The results of this experiment indicate that the repeatability error increases with measurement force, because the lapping pad inclines when it is pressed to the test surface. Probe type 2 is developed to solve this problem. Both lever ends of this probe are held by piezoelectric actuators, and the pad is attached to the center of the lever. Control system of this probe is decided form consideration of lever inclining. It is appeared that the probe type 2 has better measurement ability than probe type 1 from experimental result. In-process measurement by using probe type 2 is tested. A silicon wafer is machined by this probe under the non-linear control mode. Relation of machined amount between lapping force and machined amount between time are investigated basically.