Nano-photomask fabrication using focused ion beam direct writing

A novel nano-photomask fabrication method using focused ion beam direct writing (FIBDW) is proposed to normalize the dwell time of each pixel of the ion beam location with respect to the contrast of designed bitmaps. The removal mechanism is studied to develop the fabrication process. It has been confirmed that beam dwell time, astigmation and overlap are the most effective parameters for achieving the features in nanoscale. An approach for dot array milling is proposed also for inspecting and correcting the beam astigmatism. Photomasks with line width of 32 nm are employed for the purpose of successful application of this novel method in this study.