Wear comparison of critical dimension-atomic force microscopy tips.

Nanoscale wear affects the performance of atomic force microscopy (AFM)-based measurements for all applications including process control measurements and nanoelectronics characterization. As such, methods to prevent or reduce AFM tip wear is an area of active research. However, most prior work has been on conventional AFMs rather than critical dimension AFM (CD-AFM). Hence, less is known about CD-AFM tip-wear. Given that tip-wear directly affects the accuracy of dimensional measurements, a basic understanding of CD-AFM tip wear is needed. Toward this goal, we evaluated the wear performance of electron beam deposited CD-AFM tips. Using a continuous scanning strategy, we evaluated the overall wear rate and tip lifetime and compared these with those of silicon-based CD-AFM tips. Our data show improved tip lifetime of as much as a factor of five and reduced wear rates of more than 17 times. Such improvements in wear rate means less measurement variability and lower cost.