Method for imaging sidewalls by atomic force microscopy

We demonstrate a new method for imaging vertical and near vertical surface features by atomic force microscopy (AFM). It is based on an attractive force mode AFM, equipped with a special boot-shaped tip, coupled with a measurement of slope and with a special tracking technique. Surface profiling is achieved through a novel servo and scanning system. Mapping sidewall profile opens the door to measurement of critical dimensions (width and wall angles) of lines and trenches in integrated circuits, with high accuracy.