Focused Ion Beam Assisted Circuit Debug of a Video Graphics Chip

Abstract

Microchip circuit simulation modeling cannot always duplicate all of the independent variables found in a system level application. Sometimes, monitoring the logic states at multiple internal nodes when operating in the native environment is the only way of debugging a subtle design error. In this situation, Focused Ion Beam (FIB) technology was used to provide microprobe access points to deeply buried nets, allowing levels of real-time mapping not available by any other method. Data extraction was accomplished by probing the socketed chip on a rigidly mounted AT bus video card. The driver was a fully disassembled personal computer running a graphics intensive program. The close collaboration between failure analyst, applications engineering and the chip designers made this a truly unique experience.