Waveform Acquisition from the Backside of Silicon Using Electro-Optic Probing

A new tool (Schlumberger IDS 2000) has become available for acquiring waveforms from C4 (also known as flip chip) packaged IC’s. The waveform acquisition technique is based on electro-optic sampling through the backside of silicon. After explaining the physics of electro-optic sampling, the technique is demonstrated through the backside of Si on a simple diode test structure and a flip chip microprocessor. Also, many of the issues and challenges with this tool are discussed.