An automated test system for fault location in VLSI circuits

Abstract

The use of stroboscopic voltage contrast imaging for the design validation of prototype integrated circuits and testing of commercial devices is widely accepted. However, as circuit complexities increase, the information content of such images increases significantly and image processing techniques have proved to be useful for revealing differences in the operation between 'golden' and faulty devices. Described in this paper is a test system for VLSI circuits which combines a conventional IC tester with an electron-beam probe system, a relatively low cost image processor and PC to provide immediate 'real-time' processing as well as a significant degree of automation for the detection of faults in both commercially sourced and custom designed circuits. Colour is used to encode voltage and timing information in images to assist in the location and analysis of faults.<>