Development of photomask fabrication for 100nm-design rule

130-100nm rule lithography has rendered the mask error enhancement factor (MEF) larger and required photomasks to have tight CD accuracy. We adopted the current best photomask technology to meet 100nm-design rule. We used a negative CAR resist, the 50kV EB machine, a new puddle development using the NS (No impact Stream) nozzle, and NLD(neutral loop discharge) dry etching. Consequently, we obtained the best performance in the full scanner area and we achieved the target CD uniformity.