Contrast evaluation of SCALPEL GHOST method in 100 kV electron projection lithography

Electron projection lithography (EPL) techniques, such as SCALPEL and PREVAIL, are expected to be candidates for fabricating 80-nm devices or less. In electron-beam lithography, the proximity effect correction (PEC) is the most critical issue for obtaining sufficient dimension accuracy and good resist pattern profiles. The SCALPEL GHOST method, proposed by Watson et al. (1995), has a remarkable advantage to throughput by doing both the pattern and correction exposures, simultaneously. This method, however, degrades the exposure intensity contrast due to a larger background dose than that in other PEC methods, such as pattern modification. In this paper, we investigate the essential conditions for the SCALPEL GHOST PEC to achieve 80-nm resolution in 100 kV EFL in terms of the exposure intensity contrast.