Advances in optical densitometry for low dose measurements

The move to sub 130nm devices has driven the need to have a wafer level, high sensitivity low dose mapping capability for all species on large diameter silicon wafers. Sheet resistance mapping systems do not provide the feature sensitivity and matching capability required for precision 1E11 to 1E13 doses. The new CorMap Optical Densitometry System uses a 595nm LED light source to measure the development of dye in a photo resist polymer. The Core Systems unit bounces the light off of a coated, standard silicon wafer. After the exposure to the ion beam, a very high definition wafer level map is produced in 1 - 2 minutes (for 200mm wafers). This paper will review the areas where the CorMap (Model 200) offers unique applications for process diagnostics and ion implant monitoring for dose, energy and energy/species. Dose and energy sensitivity over a wide range (inc. 2.5 MeV+) of lower doses will be shown and compared.