The electro-rheological (ER) fluid is recently used for micro polishing of 3-dimensional micro-aspherical lenses. It is also used for polishing small area defects on wide flat wafers. Since the ER fluid shows a behavior of viscosity changing under certain electric fields, micro polishing efficiency may be enhanced for certain cases. In this paper, a perfluorinated carbonyl fluoride oil based ER fluid was used to improve surface polishing rate and submicron scale accuracy. As polishing electrodes, micro size cylindrical tools had been used for maximizing the electric field. An experimental device, which was applied for micro polishing a number of wafers of 4 inches in size and other workpieces, was made on a precision milling machine. It consisted of a steel electrode, a wafer fixture, a 10 mA current and DC 5kV power supply unit, and a controller unit. From the experiments, the ER fluid is applicable for micro polishing of small parts.

The influence of a biasing electric field on the propagation of the lowest-order antisymmetrical a0 Lamb wave modes in a bi-layered piezoelectric plate is investigated in this paper. It is found that the velocity shifts for the a0 mode due to presence of the bias field on the 10- µm LiNbO3 film structure are comparable with those observed in surface acoustic waves and Lamb waves in LiNbO3 plates. The fractional change in phase velocity of the layered piezoelectric structure is a linear function of the biasing electric field and can be used in voltage sensors.