Optical waveform probing is a critical component in flipchip diagnostics. There is a dramatic increase in the need for backside silicon probing of non-flipchip packaged devices. The effective way to implement this strategy is to package the die in a BGA carrier that allows backside analysis. Optical waveform probing has been used primarily as a digital waveform timing analysis tool. The capability of optical waveform probers can be extended to failsite isolation and qualitative analog signal analysis.