APPARATUS USING A BEAM OF POSITIVE IONS FOR CONTROLLED EROSION OF SURFACES

摘要

A process and apparatus for controllably eroding the surface of hard materials such as fused quartz, glass, metals and ceramics by the bombardment of the positive ions. Focused argon ions accelerated by potentials of up to 120,000 volts and with a constant beam current are controlled in direction to cause surface erosion of a workpiece to accuracies of up to one-one hundredth of a wavelength of green light. The workpiece is moved at a controlled rate in combination with the control of the beam direction to obtain a controlled erosion pattern over the surface of the workpiece. In another embodiment, an intensity modulated beam current is used. An electron beam is directed at the workpiece in a pattern which surrounds the ion beam to prevent the building up of a positive charge on the work surface. The progress of the erosion is observed and measured by an interferometer system. The movement of the ion beam and workpiece can follow a programmed automatic sequence.