Non-contact, in-line monitoring of low dose and low energy ion implantation

Cycle time and cost demands associated with ultra-large and giga-scale integration have fueled the need for cost effective, fast, and accurate in-line characterization techniques across all processing areas. The work presented here, is a discussion of the capabilities of new generation non-contact tools to include low dose (<1.0E12 cm^-2) and low energy (<10 keV) implant monitoring. Under these conditions, the traditional Thermawave and sheet resistance techniques are not sensitive enough to be reliably used for implant monitoring. In particular, Quantox-Surface Photovoltage (SPV), SDI-Near Surface Doping (NSD), and Carrier Illumination (CI) measurements were performed. The low dose (<1E12 cm^-2) investigation focused on boron implants used in defining the threshold voltages of CMOS devices. Boron implants with energies ranging from 1 to 13 keV were also used to investigate the ability of the techniques to monitor low energy performance. Because the measurements are non-destructive and can possibly be performed on patterned wafers, these techniques have the potential to be used for in-line implant monitoring