Self-actuated, self-sensing cantilever for fast CD measurement

摘要

The conventional optical lever detection technique involves optical components and its precise mechanical alignment. An additional technical limit is the weight of the optical system, in case a top-scanner is used in high speed and high precision metrology. An alternative represents the application of self-actuated AFM cantilevers with integrated 2DEG piezoresistive deflection sensors. A significant improvement in performance of such cantilevers with respect to deflection sensitivity and temperature stability has been achieved by using an integrated Wheatstone bridge configuration. Due to employing effective cross-talk isolation and temperature drift compensation the performance of these cantilevers was significantly improved. In order to enhance the speed of AFM measurements we are presenting a fast cantilever-approach technology, Q-factor-control and novel adaptive scanning speed procedure. Examples of AFM measurements with high scanning speed (up to 200 lines/s) committed to advanced lithography process development are shown.