Controlling the profile of shallow doped layers is critical for obtaining desired performance from deep sub-micron devices. An especially difficult challenge is measuring depth uniformity of the activated implant over the full area of a wafer.

This paper demonstrates the capabilities of a new rapid, non-contact optical technique for measuring active doping depth of shallow implants. Employing a 2 Pim spot size, it provides a measurement of fine-scale spatial uniformity in dimensions approaching those of individual devices. By measuring multiple sites, it can rapidly characterize uniformity over large areas and edge-to-edge, without an edge exclusion zone.

Data will be presented showing performance on layers varying in depth from 200 to 1200 Å. Edge-to-edge diameter scans on 8” wafers with le15, B11 implants at energies in the range of 200 to 2,000 eV and various RTA temperatures show radially symmetric uniformity patterns of depth and edge effects in the outermost centimeter. Measurements are validated based on correlation to spreading resistance profiles for a number of samples.