Line width calibration standard manufacturing and certifying method

摘要

A method of making and certifying submicron line width calibration standards includes steps of thermal growth of a silicon dioxide film layer on top and vertical side wall surfaces of silicon regions, e.g. strips or mounds, that are formed over a silicon dioxide layer on a silicon substrate, then optically measuring the top film layer thickness, removing the oxide film from the top surface of the silicon regions via a planarization technique that protects the film on the side walls, and finally removing at least some, and in most cases preferably all, of the silicon material to leave just the oxide film that was on the side walls of the former silicon regions as submicron linear features, such as extended isolated lines or connected line segments arranged in a polygon. The width of these linear features is certifiable via cross-section testing of samples that have been formed by the film layer growth by means of scanning electron or atomic force microscopy to obtain a ratio of top-to-side film thicknesses, so that the lines on the standard are determined to have widths calculated from that ratio and the optically measured top film thickness. In an alternate embodiment, an atomic force microscope probe tip determining standard can be made using the same formation steps as the line width standard except that a silicon layer with 100 top surface instead of 110 top surface for the line width standard is used. Sloping side walls on the silicon regions result so that the oxide film layer will form tilted upwardly projecting blade features when the silicon material is partially removed.