Evaluation of Shot Position Error in Electron Beam Lithography Using Overlay Metrology with `One-Shot' Inspection Mark

Electron Beam (EB) lithography is the most attractive tool for the development of the Ultra Large Scale Integrated Circuit (ULSI) devices with the finest pattern rule. It is necessary to estimate precisely the unsteadiness of the pattern positions in EB lithography. We measured shot unsteadiness in EB lithography using conventional overlay (O/L) technology with the one-shot inspection mark. The reproducibility of mark edge detection of the same mark pattern was found to have a standard deviation (σ) of less than 0.3 nano-meters (nm), and the steadiness of shot-positioning was estimated to have a σ of less than 3 nm.