MONTE-CARLO SIMULATION OF CHARGING EFFECTS ON LINEWIDTH METROLOGY

Charging effects of scanning electron microscopes on the linewidth met rology of polymethylmethacrylate (PMMA) insulator patterns are investi gated using Monte Carlo simulation. It is first revealed in detail how the nonunity yield of electron generation in the PMMA target leads to local charge accumulation and affects the image profile of secondary electrons as charging develops. Then the measurement offset due to cha rging effects is identified for various target patterns of isolated an d array types. Finally, it is concluded that the measurement uncertain ty caused by the measurement offset exceeds the error budget limit tha t will be allowed in the linewidth metrology of the next generation of semiconductors.