Apparatus and method for enhancing the uniform etching capability of an ion beam grid

摘要

A shaper for an ion beam gun is a thin, flat plate having a generally elongated, non-symmetrical profile with notches and tabs. The shaper is mounted flat to the surface of an ion beam grid having an array of holes. The shaper is oriented radially on the grid from its center to a perimeter of the grid and covers some of the holes in the grid. The grid is mounted to an ion beam gun above a specimen that is rotated beneath the ion beam gun. The large ion beam is filtered into smaller ion beamlets by the grid. The ion beamlets permeate the holes in the grid that are not covered by the shaper. The ion beamlets reach the specimen to etch it more uniformly than a grid that does not have a shaper. This phenomena is due to blockage of the higher ion beam density along the radial direction. The ion beamlets that ultimately arrive at the specimen are themselves more uniform and can produce the more uniform pattern on the specimen. The shaper may be further optimized for a particular grid via a trial-and-error process to even further refine the uniformity of etching depth.