In this paper, the feasibility of a large area exposure for the manufacturing of a NIL master (silicon wafer) dealing with a long writing time is shown. Fraunhofer CNT succeeded in a 355h exposure with a variable shaped e-beam using a commercially available positive tone chemically amplified resist. The wafer has been evaluated in terms of resist contrast and stability, CD uniformity, linearity, pattern quality and defectivity. Electron beam tool parameters like Wehnelt voltage and stage temperature have been analyzed. Different writing strategies and concepts will be considered to optimize the exposure and minimize stitching error defects.