Use of Corona Charge Photo-Conductance Decay (Charge-PCD) for fast metal contamination monitoring of high temperature processes

As the number of new materials employed in state-of-the-art CMOS circuits has increased substantially over the last few years, a clear need has emerged for fast and simple monitoring techniques that can detect electrically active metal contamination in the semiconductor substrate. In R&D facilities like IMEC, great effort is put into screening metallic contamination at different places in the process flow where contamination could potentially occur (high-k dielectrics, metal gate electrodes, new silicide materials, contact plug materials etc.). In the present work we discuss the use of a new method; corona charge photo-conductance decay (charge-PCD) for the monitoring of metallic impurities in 300 mm high temperature processing equipment, and we compare it to the conventional lifetime measurement technologies, mu-PCD and surface photo voltage (SPV). Correlation with conventional surface techniques which combine vapor phase decomposition droplet collection (VPD-DC) with total X-ray reflection fluorescence (TXRF) is also discussed.