Low-k dielectrics: a non-destructive characterization by infrared spectroscopic ellipsometry

An infrared spectroscopic ellipsometer devoted to the characterization of silicon microelectronics has recently been developed at SOPRA. Its main feature is the ability to measure on a small spot (80×200 μm) with a high signal/noise ratio. An original patented optical design suppresses back face reflection and ensures good-quality spectral measurements in the 600–7000 cm^?1 range. The excellent signal/noise ratio allows the performance of measurements in less than 30 s. Automation and real-time analysis are included to offer an operator-orientated metrology tool. Details of the instrument are presented, and its use for the characterization of different kinds of low-k dielectrics.