IC testing: From electron-beam and ion-beam techniques to scanned probe microscopes

Abstract

The rapid advance of IC design and fabrication technology is imposing increasing demands on the performance of electron beam testers and voltage contrast techniques. One industry survey predicts that the minimum feature size on IC's will be 0.1 μm by the year 2000. Current electron beam testers utilize a 0.1 μm electron probe to detect and measure surface voltages and thus will be inadequate for use on IC's with features of this size. Also, these small geometries result in very strong fields at the device surface. For instance, with a device line biased at 1 V adjacent to a grounded line and separated by 0.1 μm, the field strength near the surface is on the order of 10 kV/mm. Field strengths of this magnitude will make the collection of low energy secondary electrons very difficult and can cause significant beam deflections. Additionally, IC's in the near future may include up to 6 levels of metallization.