Improvement of signal to noise ratio in electro optical probing technique by wavelets filtering

Electro Optical Probing (EOP) technique is an efficient backside contactless technique to measure waveforms in modern VLSI circuits. The signal related intensity variation of the reflected beam is very weak therefore, to acquire a signal with enough Signal to Noise Ratio, averaging techniques are usually performed. Resulting acquisition time for one waveform is too long to implement point to point probing to image mode. To overcome this limitation, we have developed a new filtering by wavelets approach to keep a good SNR while significantly reducing this acquisition time. It opens the doors to new multipoint probing applications. In this paper, we describe the technique, its efficiency in terms of SNR, execution time and limits.